1. Introduction
The Mediterranean basin holds a rich reservoir of phenotypic tomato (Solanum lycopersicum L. var. lycopersicum) diversity and is considered a second center of diversification for this species [1,2]. This diversity emerged as a result of the evolution of the genetic variability that was initially introduced from America, plus new mutations that occurred during the plant’s long history of cultivation, shaped by the edaphoclimatic conditions found in Southern Europe and the pressure of selection impaired by the agricultural and gastronomic cultures that incorporated this new species in their fields and culinary traditions [1,3,4,5]. Although threatened by genetic erosion, a part of this diversity has been preserved up to current times and is still cultivated in the form of traditional varieties/landraces [6,7,8,9,10].
In the last 50 years, tomato landraces have been replaced by modern hybrids, characterized by higher yields, disease resistance genes and a better adaptation to commercial practices during the postharvest stage. Nonetheless, several landraces persist in local markets. The conservation of these traditional varieties is driven by cultural factors (the varieties are linked to traditional dishes) and by the existence of singular traits absent in modern varieties. Among them, flavor is usually mentioned by consumers as the key factor driving their preference for tomato landraces over modern varieties [11]. For instance, in Italy, the ‘San Marzano’ is a well-known landrace appreciated for its cooking properties [12], while other traditional varieties such as ‘Pomodoro di Sorrento’, ‘A Pera Abruzzese’ or ‘Pomodoro di Albenga’ are highly appreciated for fresh consumption [13,14,15,16]; in Spain, the ‘Pera de Girona-Montserrat’, ‘Muchamiel’ and ‘Valenciano’ varieties, among many others, are landraces distinguished by their sensory characteristics when consumed raw in a salad [17,18,19]. These sensorial differences are at the basis of landraces’ cultivation and can be explained by the different phenotypic selection strategies followed by farmers for landraces and by plant breeders for modern varieties [11], with consequent negative sensory trade-offs when selecting for high-yielding [20] and disease-resistant varieties [21]. Nevertheless, driven by consumer complaints about the lack of flavor in modern tomato varieties [20,22,23], in recent years, sensory quality has become a major focus of tomato plant breeding [24]. The advances in knowledge about the sensory traits that lead to higher consumer acceptance for fresh-market tomatoes [15,25,26] and about the genetic and chemical basis of these traits [22,26,27,28], and their inclusion in the ideotypes, seems to have narrowed the sensory distance between modern and traditional varieties [15].
The sensory ideotypes of the different tomato horticultural groups, fresh-market (cherry, salad) and processing, have been widely discussed in the literature [24,25,29,30,31,32]; nevertheless, few reports can be found for the long shelf-life (LSL) landraces cultivated in Southern Italy and Eastern Spain. LSL varieties can be defined as a differentiated tomato group [1,33] characterized by an extended fruit shelf-life, which can exceed 5 months (non-LSL tomatoes showing an average shelf-life of 1–2 weeks), under not controlled storing conditions; a small fruit size (<80 g) with a high agro-morphological diversity across accessions; and an abnormal ripening and postharvest behavior [34,35,36,37]. European LSL varieties can be classified into two main groups according to their geographic origin: the Italian group, generically referred to as ‘da Serbo’ landraces, and the Spanish group, including the ‘Penjar’ and the ‘Ramellet’ landraces [1,38]. According to Blanca et al. [1], both groups seem to have evolved from independent origins. Despite these different origins, the LSL landraces were incorporated in similar farmer traditions: anciently, they were cultivated in non-irrigated fields, harvested in bunches or individually and tied in a string to be hung in the ceilings of aerated rooms, and consumed after a storage period. The names of the varieties describe this typical method of preservation; for instance ‘Penjar’ (Catalunya region, Spain) or ‘da Appendere’ (general name used in Italy) refer to the hanging of the fruits, while ‘Ramellet’ (Balearic Islands, Spain), and ‘Piennolo’ (Campania region, Italy) refer to the harvest of the fruits in bunches [33].
The LSL phenotypes of some accessions of the ‘Penjar’ landraces from Catalonia and Valencia [37] and the ‘Ramellet’ landrace from the Balearic Islands [35] have been associated with the ripening mutation alcobaca (alc) in the coding sequence of NAC-NOR gene [39], initially described in the ‘Alcobaça’ landrace (reviewed by Conesa et al. [33]). However, the alc mutation has not been reported in Italian LSL landraces such as ‘Corbarino’ and ‘Lucariello’ [40], suggesting that other mutations might also be involved in the LSL phenotype. In fact, recently, a multi-omics study conducted on the LSL landrace ‘Lucariello’ identified the MADS-RIN gene as a possible key player in the gene regulatory network leading to the delayed fruit softening of this traditional variety [34].
Among all the tomato groups, the LSL group displays, most probably, one of the most diverse sensory landscapes within tomato. The LSL phenotype is not linked to a specific chemotype, and a wide diversity of chemical profiles have been described in the different LSL landraces. This sensory diversity is probably linked to the multiplicity of preferences and uses that these traditional varieties have across the Mediterranean basin [33]. In addition to the diversity at harvest, LSL fruits usually go through an ‘aging’ period (at least 1–2 months of storage) before they are consumed, which alters the composition of the fruit [16,36,41,42,43]. Thus, the sensory characteristics of the LSL fruits evolve during the postharvest stage, resulting in a sensory profile marked by organoleptic attributes not perceptible in fresh tomatoes at harvest. For instance, Casals et al. [44] described that during the postharvest phase, the volatile organic composition (VOC) of the ‘Penjar’ landrace was altered, resulting in the appearance of new aromas that were masked at the harvest stage.
Additionally, the LSL varieties are usually not consumed raw in a salad but used to prepare different traditional dishes. In Spain, the ‘Penjar’ and ‘Ramellet’ landraces are mainly used to prepare ‘bread with tomato’ (‘pa amb tomàquet’), while in Italy, the ‘Piennolo’ landraces are used to prepare numerous dishes, such as tomato sauces or as a pizza topping, and are only occasionally consumed raw with toasted bread (‘bruschetta’). Accordingly, the sensory expectations of consumers for these varieties are related to the quality they bring to these preparations, rather than their sensory value when eaten raw. This link between the sensory ideotype and the culinary use was previously described by a panel of chefs that evaluated ‘Penjar’ tomato landraces; in comparison with modern fresh-market varieties, they found that all the ‘Penjar’ landraces had better quality attributes for spreading the fruits on bread or preparing tomato jam but were not interesting for other purposes [45]. Despite the increasing interest in the tomato LSL group [46], to the best of our knowledge, no studies have used sensory panels (trained or consumers) to decipher the organoleptic traits that characterize these varieties at the time of consumption (i.e., after an aging period and using the traditional preparations). Thus, the sensory diversity found behind this tomato group remains unclear, as do the quality traits driving consumer preferences.
Building on these premises, the present study aimed to evaluate the effects of different agro-environmental and postharvest storage conditions on physicochemical attributes and shelf-life of the Italian ‘Piennolo’ and Spanish ‘Penjar-Ramellet’ LSL tomato fruits.
For this purpose, a partially common set of ‘Piennolo’ and ‘Penjar-Ramellet’ varieties was grown both in Italy and Spain. Moreover, to better understand the sensory attributes that drive consumers’ preferences for LSL tomatoes, the Italian ‘Piennolo’ varieties cultivated in Italy and the Spanish ‘Penjar-Ramellet’ varieties cultivated in Spain, were evaluated postharvest by trained and consumer panels as raw products, as well as processed products according to the country’s culinary tradition (cooked in Italy and spread on bread in Spain), in Italy and in Spain.
2. Materials and Methods
2.1. Plant Material
A partially common set of ‘Piennolo’ and ‘Penjar-Ramellet’ varieties was grown both in Italy and in Spain (Table 1), for a total of nine varieties cultivated in each country.
In Italy, the field trial was performed in the locality of Somma Vesuviana (Naples), on the slopes of Mount Vesuvius, in the DOP area of ‘Pomodorino del Piennolo del Vesuvio DOP’ (hereafter referred to as ‘Piennolo DOP’). The genotypes under study were cultivated during the spring–summer of 2017, in collaboration with ARCA2010 S.c.a.r.l. and a local farmer, according to the ‘seccagna’ (lack of irrigation) cultivation method traditionally adopted for ‘Piennolo DOP’. The genotypes under study were cultivated in open field, and the transplant was performed at the beginning of April. The principal stem is traditionally cut just above the first or second inflorescence to allow an early development of two–three new productive secondary shoots. Plant height is typically kept in the range of 60–100 cm.
In Italy, a total of nine varieties were grown, consisting of: (i) four Italian ‘Piennolo’ traditional varieties, Acampora (ACA), Riccia San Vito (RSV), Lucariello (LUC), Patanara (PAT) and their commercial counterpart Gran Borghese (GBO, open pollinated variety) and (ii) three Spanish ‘Penjar-Ramellet’ traditional varieties, Ramellet (RAM), Penjar 2 (PEN2) and De colgar (DEC) along with Palamós de Penjar (PdP, hybrid) as a modern counterpart (Table 1). An experimental design with 3 blocks and 63 plants per plot was used. Harvesting started at the end of June for the Italian varieties and at beginning of July for the Spanish ones.
In Spain, the field trial was performed in the locality of Palafolls (Barcelona) during the spring–summer of 2017 in collaboration with the farmers of the Conca de la Tordera cooperative. The genotypes under study were cultivated in open field, with plants conducted vertically at one stem and managed according to commercial practices of the area. Plants were fully irrigated (100% ETo) using a drip tape. Commercial fertilizers were provided via irrigation, adjusting the conductivity to about 2 dS/m, as described in Casals et al. [47].
In Spain, a total of nine genotypes were grown, consisting of: (i) three Italian ‘Piennolo’ traditional varieties, ACA, LUC and PAT, along with their commercial counterpart GBO, and (ii) three Spanish ‘Penjar-Ramellet’ traditional varieties, Ramellet (RAM), Penjar 2 (PEN2) and De colgar (DEC), along with PdP and 545 (both ‘Penjar’ hybrids) as modern counterparts (Table 1). An experimental design with 2 blocks and 50 plants per plot was used. Harvesting was carried out in July 2017, when all the plants had ripe fruits at the third truss.
2.2. Physicochemical Analyses at Harvest
In each country, 10–14 fruits at the red ripe stage (separated in 2–3 replicates in Italy; bulked in Spain) were phenotyped individually for fruit weight (FW, in g); fruit firmness (FIRM, in D.I.), measured with non-destructive durometers, Agrosta®100 USB in Italy and Agrosta®100 Field in Spain (Agrosta, Serqueux, France); and external fruit color (expressed as CIEL*a*b* coordinates and the color indices Chroma C* and Hue Angle h°), measured using Konica Minolta Chroma Meters, CR400 in Italy and CR410 in Spain (Konica Minolta. INC, Tokyo, Japan). Fruit color parameters and fruit firmness were measured on two different positions of the equatorial region of the fruit. Soluble solids content (SSC; 6 fruits measured individually in Spain; 3 pools of 6 fruits measured in bulk in Italy) was measured using a digital refractometer ATAGO PAL-1 (Atago, Tokyo, Japan) in Italy and a handheld Brix refractometer ERMA (0–18%) (Erma, Tokyo, Japan) in Spain.
2.3. Phenotypic Characterization during Postharvest
In Italy, according to the traditional practices, the whole trusses were harvested for the Italian varieties, while for the Spanish ones, single fruits were harvested at red ripe stage. In both cases the fruits were placed in wood boxes and kept in the farmer’s traditional storing facility, consisting of an aerated room without temperature and humidity conditioning. According to traditional practices, the fruits were left untouched for the first month, and then the decayed fruits were discarded. For the ‘Piennolo’ varieties, only the first fruits of each truss were sampled for the analyses. Due to fruit number limitations and to a very poor shelf-life, the Spanish varieties could be sampled and analyzed only at harvest (T0), with measurements taken on the 3 replicates. On the other hand, the five Italian varieties, which produced a higher number of fruits with a longer shelf-life, were sampled and analyzed at harvest (T0) and at T2 (4.5 months postharvest), the latter corresponding to the time when sensory analyses (by trained and consumer panels) were also conducted.
The trends for FW, FIRM, SSC and external fruit color were monitored at T0 and T2, as previously reported. In addition, at T2, titratable acidity (TA) was also measured. For this purpose, for each replicate, 6 fruits were cut longitudinally to obtain 2 halves; one half of each fruit was homogenized using a common kitchen blender Girmi FR75 (Girmi, Rimini, Italy) for 1 min. A part of the homogenate was centrifuged with a Rotina 420 R centrifuge (Hettich Zentrifugen, Tuttlingen, Germany) for 10 min at 4000 rpm, and the supernatant was used to measure TA (g citric acid/100 g) by potentiometric titration of the sample (titration to pH 8.1 with 0.1 M NaOH) using a FiveEasy pH-meter (Mettler Toledo, Columbus, OH, USA). Taste index (TI) was calculated according to Navez et al. [48] from the SS and TA values using the formula TI = TA + (SS/(20 × TA)).
In Spain, single fruits were harvested at the red ripe stage, placed in plastic boxes and stored at controlled temperature (19 °C) and relative humidity (90%) up to the time of the analyses. Fruits were surveyed weekly, and decayed fruits were eliminated. In Spain, the shelf-life (expressed as the % of sound fruits) of the two LSL tomato groups could be analyzed up to 2 months, as the ‘Piennolo’ varieties did not last longer than that. Moreover, 15 fruits per variety were stored separately and weighted individually at harvest and after 2 months to study the fruit weight loss (in %). Due to the reduced number of sound fruit of the ‘Piennolo’ group cultivated in Spain, fruit weight loss at 2 months postharvest could only be measured for the ‘Penjar-Ramellet’ varieties. For these fruits, individual measurements of the external color were also performed to study the color evolution, as previously reported.
2.4. Descriptive Analysis
In Italy, descriptive analysis (DA) by a trained panel was conducted in November, at 4.5 (T2) months after harvest, which falls within the representative period of greater sales for the ‘Piennolo’. The five ‘Piennolo’ varieties cultivated in Italy (ACA, LUC, PAT, RSV, GBO) were evaluated by a panel consisting of eight professional assessors specifically trained in the sensory evaluation of tomato [15,49]. The ‘Piennolo’ variety is usually consumed cooked, added to prepared dishes, and is only occasionally raw with toasted bread. For this reason, visual and olfactory descriptors were evaluated on the raw products, whereas ‘odor’ and ‘in mouth’ evaluations were performed on the baked tomatoes.
Raw tomatoes were removed from the stalk, washed with tap water, dried with a towel and served to panelists at room temperature (20 ± 2 °C) in containers coded with three-digit numbers. A whole tomato was presented; a kitchen knife was given to each judge. For evaluation of the cooked product, tomatoes were cut lengthwise into two pieces and baked in a professional multifunction combi oven (TOP 6x1/1GN GAS) (Angelo Po Grandi Cucine S.p.A., Modena, Italy) at 215 °C with 20% steam for 4 min. Participants were provided with two halves of baked tomatoes (40 ± 2 °C).
The lexicon included 21 descriptors: 7 attributes (3 appearance, 1 texture, 3 olfactory) were measured directly on the raw fruit (Table 2), while the other 14 were measured on the baked fruit (2 olfactory, 6 in mouth with the skin, and 6 in mouth after removing the skin) (Table 3). Each attribute was rated by using a continuous 0 to 9 line scale, with endpoint labels defined as shown in Table 2 and Table 3. Three evaluations were performed on each variety (one for each replicate). The samples were split over two days. Seven or eight products were evaluated in each day in monadic order and best balanced among participants. All the products were tasted, under white light, at CREA-AN sensory laboratory, conforming to international standards approved for sensory analysis [50].
In addition to the quantitative evaluations, in Italy, the olfactory impression on the raw products was also explained by 8 comments that the panel could check as either ‘yes or no’: pea/legume, herbaceous, stem (stalk, tomato leaf), floral, fruity, baked tomato (over ripe, tomato paste, tomato juice/sauce), undergrowth (hearty, musty, humus, mushroom) and diacetyl-like. The panel experts were allowed to give other perceptions, which they had to specify. Flavor impression of the baked products was explained by 2 comments: pea/legume and green/unripe (unripe fruit, grass, cut grass). Moreover, the panelists were asked to specify if they could perceive other flavor notes not included in the list.
In Spain, sensory analyses by the trained panel were conducted at three months (T2) after harvest. Previous studies determined this as the maximum storage period starting from which important sensory attributes are lost in the ‘Penjar’ tomato [44]. The five ‘Penjar-Ramellet’ varieties cultivated in Spain (DEC, PEN1, RAM, PdP, 545) were evaluated by a panel composed of seven panelists, specifically trained in the sensory evaluation of tomato [15,17].
‘Penjar’ and ‘Ramellet’ tomatoes are mainly used to prepare ‘bread with tomato’ (fruit is cut in 2 halves and rubbed on bread). For this reason, and to obtain a complete evaluation of the sensory profile, visual, olfactory and taste attributes were measured on the raw fruits (Table 2) and on the culinary preparation (‘bread with tomato’) (Table 4). Organoleptic traits describing the fruit quality for preparing ‘bread with tomato’ were added in the sensorial descriptions (i.e., ‘spreadability’, ‘seed presence on bread’) (Table 4).
For the evaluation of the raw tomatoes, a procedure similar the one described for the Italian trial was used, and whole fruits were also served in this case. To evaluate the quality of the different varieties for preparing ‘bread with tomato’, each panelist was served with a knife and a slice of bread, following the methodology previously described by Romero del Castillo et al. [45]. Panelists were asked to cut the fruit equatorially and then to rub the fruit halves onto the bread and score the ‘spreadability’.
Each sample was evaluated twice, using 17 sensory attributes: 10 attributes were measured directly on the raw fruit (Table 2), and the other 7 attributes were measured on the culinary preparation (‘spread on bread’) (Table 4). Each attribute was rated using a continuous 0 to 10 scale, with endpoint labels defined as shown in Table 2 and Table 4. Genotypes and their repetitions were distributed randomly in different sessions, comprising a maximum of five samples per session. Each panelist received a whole fruit to conduct the sensory test in a monadic sequence. Sensory sessions were carried out in a room designed for sensory analyses, under white light, conforming to international standards approved for sensory analysis [50]. Sensory sessions were held in October 2017 at the laboratories of the Barcelona School of Agricultural Engineering.
In addition to the quantitative evaluations, also in Spain, the olfactory impression on the raw products was explained by 8 comments that the panel could answer with ‘yes or no’ (Table 2).
2.5. Consumer Tests
In parallel to the DA, hedonic tests were conducted in one large city per country: Naples (at T2, 4.5 months postharvest) and Barcelona (at T2, 3 months postharvest).
The Italian consumers tasted the five ‘Piennolo’ varieties cultivated in Italy (ACA, LUC, PAT, RSV, GBO) and evaluated by the Italian trained panel, while the Spanish consumers tasted the five ‘Penjar-Ramellet’ varieties cultivated in Spain (DEC, PEN1, RAM, PdP, 545) and evaluated by the Spanish trained panel. In both countries, consumers’ recruitment criteria were the following: (i) consumption of the target product (at least once a month) and (ii) interest and willingness to participate. On the other hand, working in the food and drinks industry and suffering from eating disorders, food allergy or intolerance were exclusion criteria. At the screening stage, information on consumers’ socio-demographic data including education, responsibility in shopping and tomato consumption frequency, were also collected.
In Italy, hedonic tests were performed in November 2017 with a panel of 103 consumers, balanced for gender (49.5/50.5% F and M), recruited by a service provider in Naples. The distribution in the age classes was the following: 18–24 years: 15.5%; 25–34 years: 16.5%; 35–49 years: 34%; 50–64 years: 34%. Central Location Testing (CLT) was conducted, under white lighting, in a standard sensory lab designed for sensory analyses, according to ISO 8589 [50]. Groups of 9–10 people took part in one 40 min session during which they evaluated the 5 Italian tomato varieties, first as raw and then as baked. Mineral water with low saline content was served in between the samples to neutralize the palate. The same protocol as the one described for descriptive analysis was used for products preparation. The only difference concerned the cooking method, which, for practical reasons, was conducted in a microwave oven (NN-GD38HSSUG, Panasomic, Kadoma, Japan) at 900 W for 4 min (500 g of product). The two cooking procedures were preliminarily compared to ensure that no differences were induced due to the cooking method. The questionnaire comprised four hedonic judgments: ‘aspect liking’ and ‘odor liking’ (raw products), ‘flavor liking’ (baked products) and ‘overall liking’ (raw and baked products). A 9-point hedonic scale with three labelled categories was used: 1 = Dislike Extremely; 5 = Neither Like nor Dislike; 9 = Like Extremely. Consumers were also asked to answer a consumption habits questionnaire. The products were served in sequential monadic presentation and the order of testing was balanced (Williams Latin square). No dummy sample was served as a first product.
In Spain, the consumer test was held in October 2017 at the facilities of the Barcelona School of Agricultural Engineering (Polytechnic University of Catalonia). The test was carried out in a room designed for sensory analyses, according to ISO 8589 [50]. A total of 94 consumers performed the test, but in the end, 91 were considered valid for completeness of answers. Consumers were recruited by the sensory lab of the Barcelona School of Agricultural Engineering. Groups of 12 people took part in one 40 min session during which they evaluated the 5 Spanish tomato varieties, first as raw product and then as ‘bread with tomato’. Mineral water with low saline content was served in between the samples to neutralize the palate. The same product preparation protocol as the one described for descriptive analysis was used. The questionnaire comprised four hedonic judgements: ‘aspect liking’ and ‘odor liking’ (raw products), ‘overall-liking spreadability’ (i.e., acceptance in the process of rubbing the tomato on the bread), and ‘overall liking’ (spread on bread). A 9-point hedonic scale with three labelled categories was used: 1 = Dislike Extremely; 5 = Neither Like nor Dislike; 9 = Like Extremely.
The samples were presented in a random monadic sequence. Socio-economic data of the consumers show that participants had an equitable distribution between genders (41.6% male, 57% female, 1.4% not declared). Nevertheless, some categories were overrepresented in the population, such as young ages (18–24 years: 42%; 25–34 years: 15%; 35–49 years: 15%; 50–64 years: 20%; >65 years: 8%) or high education levels (high school: 48%; upper secondary school: 35%).
All subjects recruited in Italy and Spain gave their informed consent to participate in the study, which was approved by the CNR Research Ethics and Integrity Committee (IRB, Prot. N. 0070284/2021). Personal data were protected by anonymization according to National Data Protection Regulations.
2.6. Statistical Analyses
At harvest (T0), to study the phenotypic differences between the LSL varieties originating from the two countries, the Italian accessions (GBO, ACA, LUC, PAT, RSV) were referred to as the ‘Piennolo’ group and the Spanish ones (PdP, RAM, PEN1, PEN2, and DEC) were referred to as the ‘Penjar-Ramellet’ group. The phenotypic differences between genotypes and growing sites were studied by means of a mixed lineal model, considering the genotype × growing site as the whole fixed factor, and the genotypes as the within-unit random factor (lme4 R package [51]). Mean separation was performed with the Tukey’s honestly significant difference (HSD) post hoc test (p < 0.05). Subsequently, the effect of the growing site, Italy (ITA) or Spain (SP), on each individual genotype was assessed by using the Mann–Whitney–Wilcoxon pairwise test. Median of treatments and the deviation of individual values from the mean were plotted using boxplots with the ‘ggplot’ R package [52].
The effect of storage on fruit quality traits was recorded separately in each country: in Italy, the study was performed for the ‘Piennolo’ accessions (Piennolo_ITA) and in Spain for the ‘Penjar-Ramellet’ ones (Penjar_SP). Accordingly, data were analyzed separately for each country. General trends for each LSL group were studied between the data recorded at harvest (T0) and at the time of sensory analyses (T2 = 4.5 months in Italy, 3 months in Spain) using a linear ANOVA model considering the postharvest times as a fixed factor and the genotype as the random factor. To dig into genotype-by-postharvest interactions, we further analyzed the differences between T0 and T2 postharvest times separately for each genotype, using a one-way ANOVA. Finally, for the shelf-life trait recorded in the ‘Penjar-Ramellet’ and ‘Piennolo’ varieties grown in Spain, differences among genotypes were compared using a one-way ANOVA with the genotype as a fixed factor. Mean separation was performed using the Tukey’s test.
Sensory, consumer and physicochemical data, collected at 4.5 (T2) months postharvest in Italy and at 3 (T2) months in Spain, were analyzed using the XLStat (ver. 19.4; Addinsoft, New York, NY, USA) software package. Significance of differences (p < 0.05) was determined using ANOVA and Tukey’s test on quantitative variables and Kruskal–Wallis and multiple pairwise comparisons using Dunn’s procedure (two-tailed test) on categorical variables. Principal Component Analysis (PCA) was used to model product differences between the overall of physicochemical, descriptive sensory and hedonic data in Italy and between descriptive sensory and hedonic data in Spain. Consumers’ liking scores were analyzed with ANOVA and Fisher’s (LSD) post hoc test (p < 0.05).
3. Results
3.1. Characterization of LSL Tomato Varieties at Harvest
Regarding the evaluations conducted at harvest, the effect of the agro-environment was significant for both LSL groups (‘Piennolo’ and ‘Penjar-Ramellet’) and for all the traits measured (except for the b* color coordinate) (Figure 1).
When grown under their original conditions (ITA, low input and no irrigation), the ‘Piennolo’ accessions were characterized by significantly lower FW (14–16 g), higher SSC (9–10 ºBrix), lower FIRM (55–60% D.I.) and more intense redness (a*, 32–37) than when they were grown in Spain (SP) under high input and full irrigation (Figure 1). Similarly, significant differences were found with the ‘Penjar-Remellet’ accessions, which showed higher FW (67–110 g), lower SSC (3.2–5.2 °Brix), higher FIRM (74–80% D.I.), higher lightness (L*, 43–46) and lower redness (a*, 16–21) when grown in SP under their original management practices than when they were grown in ITA. Thus, phenotypically, both groups were clearly different when grown under their original agro-environmental conditions. These differences were confirmed when the genotypes were analyzed individually (Figure S1). The specific agro-environment of the ITA field, which included lack of irrigation and low-input conditions, determined in both LSL groups a significant increase in SSC and redness (a*) and a decrease in FW and FIRM, while lightness (L*) was solely affected in the ‘Penjar-Ramellet’ group (Figure 1).
3.2. Shelf-Life and Effect of Postharvest on Fruit Quality Traits
The strong impact of the typical agro-environment of each country trial on the postharvest behavior of the various genotypes has led to a reduced shelf-life of the Spanish genotypes bred in Italy and vice versa. Specifically, in the Italian trial, the ‘Penjar-Ramellet’ varieties showed a very poor shelf-life, which prevented postharvest evaluations of these genotypes. A similar trend was observed for the Spanish trial, where, after 2 months of storage, the ‘Piennolo’ varieties showed a significantly lower shelf-life (<25%) than the ‘Penjar-Ramellet’ varieties, which reached a shelf-life higher than 55% (Figure 2). In addition, fruit weight loss recorded on the ‘Penjar-Ramellet’ varieties during storage ranged between 6.0 (RAM) and 8.4% (PdP), with significant differences observed between genotypes (Figure S2).
With respect to the phenotypic traits recorded at T0 and T2 (4.5 months postharvest) on the five ‘Piennolo’ varieties cultivated in Italy, a clear mean reduction in FIRM (56%), SSC (22%) and FW (13%) was reported during storage (Figure S3). Furthermore, overall, significant increases were observed for the external fruit color coordinates L* and b*, while a* significantly decreased (Figure 3). For a*, the trend was confirmed for all genotypes, while for b*, it was observed for three of the five accessions, and for L*, only PAT showed a significant increase (Figure S4). In Spain, overall, the pattern of color evolution recorded on the four ‘Penjar-Ramellet’ varieties showed a significant difference only for the a* coordinate, which increased between T0 and T2 (3 months postharvest) (Figure 3). This trend was confirmed for all genotypes, except for PEN1, which showed a significant increase in the b* coordinate (Figure S4).
3.3. Sensory Quality and Consumer Preferences in Postharvest
To better understand the sensory attributes that drive consumers’ preferences for LSL varieties postharvest, the Italian and Spanish genotypes were characterized by an objective description of sensory properties and by a hedonic test. After a postharvest storage period, each variety was evaluated raw and as processed products according to the country’s culinary tradition (cooked in Italy and ‘spread on bread’ in Spain).
3.3.1. Italian Evaluation
In Italy, four ‘Piennolo’ landraces (ACA, LUC, PAT, RSV) and their commercial counterpart (GBO) were evaluated at 4.5 (T2) months after harvest, which falls within the representative period of higher sales for these LSL tomatoes.
ANOVA was performed on descriptive analysis data using sample, replicate and their interaction as variation factors. The analyses conducted on the raw products highlighted statistically significant differences among the varieties for the sensory descriptors ‘color intensity’, ‘shriveling’, ‘seeds’, ‘resistance to cut’, ‘green odor’ and ‘ripe tomato’. A significant replicate effect was found for ‘shriveling’ and ‘ripe odor’ (Table S1). With respect to baked tomatoes, a significant variety effect was observed only for ‘skin–bitter persistence’, which was scored higher in GBO (3.4) compared to the four ‘Piennolo’ landraces. In addition, a significant replicate effect was observed for ‘skin-sweet’, ‘skin-bitter’, ‘skin-bitter persistence’ and ‘bitter taste’ (Table S1).
The tomato products (raw and baked) were also characterized for olfactory and flavor notes. Occurrences of these sensory notes, expressed as percent frequencies, are illustrated in Table S2. For the raw products, ‘herbaceous’ and ‘stem’ odors were the most represented olfactory notes, which were confirmed in all varieties with a frequency higher than 72.7% and 40%, respectively. Statistically significant differences were observed only for the ‘green-unripe flavor’ note checked on baked tomato products; the frequency of this flavor note was significantly higher for PAT than for all other varieties.
As regards the physicochemical parameters, measured on the raw products at T2, a highly significant variety effect was observed for all parameters except for FW (Table S3). In addition, ANOVA showed a significant replicate effect on five traits: TA, pH, SSC, SSC/TA and TI.
The three sets of quantitative data (physicochemical, descriptive sensory and hedonic) obtained for the raw and baked ‘Piennolo’ products and samples were modelled in a PCA (Figure 4). The first (PC1) and second (PC2) principal components of the PCA accounted for 44.22% and 26.96% of the total variation in the data, respectively.
The PC1 was positively correlated mainly with FIRM, the five external color parameters (L*, a*, b*, ho and C*), ‘resistance to cut’, ‘aspect liking_R’ and ‘odor liking_R’. These attributes and hedonic judgments were opposed by the physicochemical parameters SHR and a*/b* and by the sensory attributes ‘shriveling’, ‘color intensity’, ‘seeds’ and ‘ripe odor’, all evaluated on raw products. In addition, the PC1 also correlated negatively with descriptors evaluated on the baked products with (‘skin-hardness’ and ‘skin-bitter taste’) and without the skin (‘overall odor’ and ‘bitter taste’).
The PC2 was positively associated mainly with ‘overall odor’, ‘green odor’, TA and pH when evaluated on the raw products and with numerous sensory attributes evaluated on baked products, including ‘overall flavor’, ‘acid taste’, ‘skin-bitter persistence’, ‘skin-bitter taste’ and ‘baked tomato odor’. The variables that contributed the most to the variance explained by the negative semi-axis of PC2 were: ‘skin-sweet taste’, SSC/TA, ‘ripe odor’ and taste index (TI). The projection of the five Italian ‘Piennolo’genotypes in the PCA plot revealed a clear separation of the three landraces PAT, LUC and ACA, showing higher positive coordinates along the PC1, from the landrace RSV and the commercial counterpart GBO. In addition, there is also a separation of RSV, and to a minor extent of ACA, on the negative semi-axis of PC2 from the other genotypes, particularly from GBO.
For the four consumers’ liking judgments, the average scores of the tomato products (raw and baked) ranged between 5.1 and 6.1, showing that no product was rejected (Table S4). However, the ANOVA results revealed small significant differences in appreciation only for ‘aspect liking’ evaluated on the raw tomato products, with consumers preferring the traditional varieties ACA and PAT compared to the commercial counterpart GBO (Table S4).
The analysis of the impact of socio-demographic factors on hedonic judgments showed a significant (p < 0.05) influence of gender and education level on ‘aspect liking’, ‘flavor liking’ and ‘overall liking’, with higher scores observed for males in all cases. Age significantly influenced only ‘flavor liking’ of the baked products, and the genotypes tested were appreciated more by elderly consumers (5.8) than by the young ones (4.9) (Table S5). In addition, socio-professional status had a significant (p < 0.05) effect on all liking judgments, with the highest scores recorded for the ‘retired’ consumers. Finally, the consumption frequency had a significant effect on ‘aspect’, ‘odor’ and ‘overall liking’.
3.3.2. Spanish Evaluation
In Spain, the five Spanish ‘Penjar-Ramellet’ varieties, three landraces (DEC, PEN1, RAM) and two modern counterparts (PdP and 545), were tested at T2 (3 months) after harvest, both as raw and processed (‘spread on bread’) products.
ANOVA conducted on descriptive analysis data revealed significant differences among varieties for 5 of the 10 sensory attributes evaluated on raw tomatoes: ‘color intensity’, ‘shriveling’, ‘overall odor’, ‘acid taste’ and ‘off-flavor’ (Table S6). On the other hand, for the processed products (tomatoes spread on bread), statistically significant differences were found for the sensory attributes ‘spreadability’, ‘seeds’ and ‘color intensity’ (Table S6). The landrace PEN1 showed a different sensory profile, with the highest values for ‘overall odor’ and the lowest values for ‘color intensity’ and ‘shriveling’. In addition, this genotype had good scores when spread on bread, showing an intermediate ‘spreadability’, low ‘seeds’ and high ‘sweet taste’. No significant session effect was found either for the raw or the processed tomatoes (Table S6).
The characterization by the Spanish trained panel of olfactory impression on raw tomatoes of the ‘Penjar-Ramellet’ group identified ‘fruity’, ‘floral’, ‘stem’ and ‘undergrowth’ as the most cited odor notes, with higher frequencies obtained for ‘fruity odor’ (>40%) (Table S7). The Kruskal–Wallis test did not reveal any significant difference between accessions; however, it is worth noting that the ‘baked tomato odor’ was perceived only in the modern variety PdP.
A PCA was conducted to map sample data, descriptive sensory data and consumer data obtained for the five ‘Penjar-Ramellet’ varieties (Figure 5).
The results show that the first two PCs accounted for 71.33% of the total variation in the data, with PC1 and PC2 representing 48.37% and 22.96% of the variance, respectively. The PC1 was positively correlated mainly with ‘color intensity’ of both raw and bread spread with tomato, ‘seeds’, ‘seeds_on bread’, ‘aspect liking‘ and ‘overall liking-spreadability’ related to ease of making bread with tomato. Whereas the negative semiaxis of PC1 was mainly associated with the sensory descriptors ‘sweet taste’, ‘ripe odor’, ‘overall odor’ and ‘acid taste’, all evaluated on raw products. The second axis (PC2) was positively correlated with ‘odor liking’ (raw product) and negatively with ‘overall odor’ and ‘green odor’. The projection of the five genotypes in the PCA plot showed a separation between 545 and RAM, positioned on the positive semi-axis of PC1, and the three genotypes PdP, DEC and PEN1.
Different liking judgments were scored by the consumers on raw (‘aspect liking’ and ‘odor liking’) and processed (‘spread on bread’) products (‘overall liking-spreadability’ and ‘overall liking’). Analysis of variance revealed that highly (p ≤ 0.001) significant differences in appreciation among the products were detected for ‘aspect liking’, ‘overall liking-spreadability’ and ‘overall liking_on bread’; additionally, significant (p < 0.05) differences were found also for ‘odor liking’. Specifically, the variety 545 and the landrace DEC were the most appreciated for ‘aspect liking’; however, while DEC was also appreciated in terms of ‘overall liking (on bread)’, 545 showed the lowest value for this liking judgment (Table S8).
The analysis of the impact of socio-demographic factors on hedonic judgments showed a highly significant (p < 0.001) effect of gender on all liking judgments, with higher scores observed for males in all cases. In addition, socio-professional status showed a significant (p < 0.05) influence on ‘overall liking-spreadability’ (Table S9).
4. Discussion
European LSL landraces represent a singular horticultural group within the diversity of cultivated tomato. Spain (e.g., ‘Penjar’, ‘Ramellet’, ‘de Colgar’) and Italy (e.g., ‘Piennolo’, ‘da Serbo’, ’da Appendere,’ ‘d’Inverno’) are the most important areas where these landraces are grown [33]. Italian and Spanish LSL landraces share common postharvest behaviors and consumption habits which generally involve the use of the fruit after a long storage period (2–6 months postharvest) and as an ingredient in different culinary preparations rather than as raw products. Despite these common properties, phenotypic [2] and genomic analyses [1,38] have revealed a clear distinction between these two tomato LSL groups. The uniqueness of each group is determined not only by genotypic characteristics but, above all, by the interaction of the genotypes with very peculiar local growing and consumption conditions. In fact, these LSL tomato groups have been selected for their adaptation to the local environmental conditions, for low-input cropping and for their use [16,53].
In this study, the effects of different agro-environmental and postharvest storage conditions on fruit quality attributes of Italian ‘Piennolo’ and Spanish ‘Penjar-Ramellet’ LSL tomato accessions have been evaluated at harvest and postharvest. Specifically, a subset of five Italian ‘Piennolo’ (four landraces and one commercial counterpart) and six Spanish ‘Penjar-Ramellet’ (four landraces, two modern varieties) genotypes were studied. The results obtained at harvest indicate that despite all being classified as LSL tomatoes, the ‘Piennolo’ and ‘Penjar-Ramellet’ groups showed clearly distinct fruit phenotypes. Furthermore, the ‘Piennolo’ group grown in Italy was characterized by a significantly lower FW (with very low variability among genotypes), higher SSC, lower FIRM and higher redness than when it was grown in Spain. On the other hand, the ‘Penjar-Ramellet’ group cultivated in Spain was characterized by significantly higher FW (with high variability among genotypes), lower SSC, higher FIRM and lower redness than when it was cultivated in Italy. These results are in accordance with those reported by Pons et al. [2] and Conesa et al. [33]; however, in the present study, the phenotypes of the two LSL groups were compared when grown under the original agro-environments, a condition which might have accentuated the differences.
Our results have shown that the agro-environmental conditions traditionally adopted for the ‘Piennolo’ variety, which also include a “seccagna” (lack of irrigation) cultivation method, significantly increased SSC and redness while reducing FW and FIRM in both the ‘Penjar-Ramellet’ and ‘Piennolo’ groups. These effects of water deficit on fruit quality traits have been widely reported in the literature for the LSL tomato group [36,54,55,56] and are similar to those described for tomatoes in general [24]. Taken together, our data show that the ‘Piennolo’ and ‘Penjar-Ramellet’ accessions analyzed in this study lost their peculiar phenotype when not cultivated in their original agro-environmental conditions.
The present study also revealed that the agro-environmental factors of each locality (Spain and Italy) impact the postharvest behavior of both ‘Piennolo’ and ‘Penjar-Ramellet’ groups. In fact, in Spain, the ‘Piennolo’ group did not express the long shelf-life trait, while in Italy, this trend was observed for the ‘Penjar-Ramellet’ group. This indicates that the long shelf-life of each LSL group has been selected and optimized under the original agro-environmental conditions, which may include both abiotic and biotic factors, and points to the effect of those conditions on the LSL trait. Previous works aiming to decipher the impact of preharvest factors on the LSL phenotype have revealed a positive impact of water deficit [57] and low-input conditions [47] on the shelf-life of Spanish LSL landraces. Of note, and as also highlighted in the present study, these effects are genotype-dependent, which has limited the advancements in deciphering the preharvest factors that drive a long storage in the tomato LSL group.
Regarding the evolution of fruit color during the postharvest period, the ‘Piennolo’ (grown in Italy) and ‘Penjar-Ramellet’ (grown in Spain) groups showed a different pattern, the most important being the increase and the decrease in redness for the ‘Penjar-Ramellet’ and the ‘Piennolo’ groups, respectively. Moreover, a reduction in SSC, FIRM and FW was observed during postharvest in the ‘Piennolo’ group; this trend was also previously described in ‘Penjar’ landraces [36,41].
In the past, tomato breeding has been focused on yield and resistance to biotic and abiotic stresses, neglecting the fruits’ sensory quality [11]. Consumer dissatisfaction with the flavor of modern tomato varieties has made sensory quality become another important goal of tomato breeding. Along these lines, in recent decades, several studies have outlined the main drivers of tomato liking for fresh-market tomatoes [15,25,26,49,58]. However, the identification of the sensory traits that determine consumer acceptance has not been addressed in the LSL tomato group, a fact that limits the drawing of ideotypes for breeding programs and the design of cultivation systems that maximize the quality of the fruits that are marketed.
To the best of our knowledge, the present work constitutes the first sensory description conducted postharvest of the Italian ‘Piennolo’ and Spanish ‘Penjar-Ramellet’ LSL tomato groups using both trained and consumer panels. Our results refer to the sensory profiles and consumer preferences obtained postharvest for the ‘Piennolo’ group, cultivated and evaluated in Italy, and the ‘Penjar-Ramellet’ group, cultivated and evaluated in Spain. The data show that apart from the different fruit physicochemical characteristics, the ‘Piennolo’ and ‘Penjar-Ramellet’ groups also present different sensory profiles. In fact, when the ‘Piennolo’ genotypes were evaluated raw, all the descriptors, except for ‘ripe odor’, were characterized by intermediate to high scores. In contrast, the ‘Penjar-Ramellet’ group was characterized by low scores for the descriptors ‘overall odor’ and ‘green odor’, as well as for ‘sweet taste’ and ‘acid taste’. The latter two, however, were not evaluated in the raw products of the ‘Piennolo’ genotypes, which are generally not eaten raw. Moreover, for the ‘Penjar-Ramellet’ group, a wide sensory variation was perceived by the panel for ‘color intensity’, ‘shriveling’ and ‘off-flavor’, and overall, this LSL group showed a weak flavor.
With regard to the evaluations of the culinary preparations, for the ‘Piennolo’ group, a reduction in sensory diversity among the genotypes was observed for the baked tomatoes compared to the raw products; in fact, for the baked tomatoes, only 1 (‘bitter persistence of skin’) out of 14 descriptors showed a statistically significant difference. In contrast, in the ‘Penjar-Ramellet‘ group, the raw products and the culinary preparations (bread with tomato) were both characterized by sensory diversity. Therefore, cooking might have flattened the sensory differences among the ‘Piennolo’ accessions. In line with these results, Hongsoongnern et al. [59] found that after a higher degree of tomato processing, the differences in flavor due to the genotypic effect became minimal.
In addition, ‘Piennolo’ baked tomatoes were characterized by intermediate ‘baked tomato’ odors and flavors, low taste intensity (‘sweet’, ‘acid’, ‘bitter’ and ‘salty’) and intense ‘overall flavor’. The skin was highly perceived in this culinary preparation (high ‘hardness’) and it seems to have an important contribution to the ‘overall flavor’. For the bread with tomato of the ‘Penjar-Ramellet’ group, a wide range of variation for ‘color intensity’ and ‘seeds’ was observed. For the other sensory traits, there was much less diversity, and the bread with tomato products were characterized by low ‘sweet taste’ and ‘acid taste’. Moreover, most of the ‘Penjar-Ramellet’ genotypes showed a high ‘spreadability’; this sensory characteristic can be related to the singular evolution of fruit firmness and turgidity in this LSL group, caused by the downregulation of most of the cell wall-modifying genes, as described by Kumar et al. [60].
The weak sweet taste and acid taste of both LSL tomato groups at the time of consumption (T2) are consistent with the decreases in reducing sugars (glucose, fructose) and organic acids (malic, citric) that occur during the postharvest period, as has been previously reported for the ‘Penjar’ [36,41,60], ‘Ramellet’ [35] and ‘Piennolo’ landraces [42,43]. As for the intensity of odor and flavor descriptors, evaluated in both raw fruits and culinary preparations, the ‘Piennolo’ group was characterized by higher scores than the ‘Penjar-Ramellet’ group. This can be the result of a different volatilome of the two LSL tomato groups after the storage period. In fact, despite the scarcity of studies analyzing the evolution of volatile organic compounds (VOC) in LSL tomato landraces during the postharvest period, the works of Casals et al. [44] on the ‘Penjar’ landraces and of Manzo et al. [43] and Parisi et al. [16] on the ‘Piennolo’ landraces point out a different VOC pattern between the two tomato LSL groups. For the ‘Penjar’ landraces, Casals et al. [44] described a general reduction in the concentration of all the VOCs (with some exceptions such as nonanal and α-pinene), while for the ‘Piennolo’ landraces, Parisi et al. [16] and Manzo et al. [43] reported a general increase in the main VOCs contributing to tomato odor and flavor (alcohols, carbonyl compounds, phenolic derivates, and terpenes) during storage. The high intensity of ‘green odor’ perceived by the Italian trained panel in the ‘Piennolo’ group is consistent with the high concentration of VOCs such as €-2-hexenal and hexanal previously reported in the ‘Piennolo’ landraces [16,43] and described as ‘green leaf volatiles’ for their characteristic ‘fresh aroma of cut grass’ [61].
To better understand the sensory attributes that drive consumers’ preferences for LSL tomato, in the present study, hedonic tests were conducted on both raw and culinary preparations of the ‘Piennolo’ and ‘Penjar-Ramellet’ genotypes. Overall, the PCAs revealed that sensory attributes driving consumer acceptance are specific for each LSL tomato group. For the ‘Piennolo’ group, there were differences only in the ‘aspect liking_on raw’ associated with the CIELAB color parameters (except a*/b*) and higher firmness (FIRM, and ‘resistance to cut’). In contrast, in the ‘Penjar-Ramellet’ group, the major contributors to ‘aspect liking_on raw’ were ‘color intensity’ and ‘seeds’ (evaluated on raw and on bread), ‘shriveling_on raw’ and ‘spreadability’ (evaluated on bread). Furthermore, in the ‘Penjar-Ramellet’ group, a negative relationship was observed between the hedonic judgments related to smell and taste (‘odor liking’, ‘overall liking_on bread’) and those related to appearance (‘aspect liking’).
In the ‘Piennolo’ group, the raw products of landraces ACA and PAT were preferred by consumers for their evaluated aspect attributes, while the commercial counterpart GBO was the least appreciated variety. This result was largely driven by the fruit textural characteristics, as GBO was perceived as the most ‘shriveled’ genotype, while ACA and PAT had the highest scores for ‘resistance to cut’ and instrumental FIRM. In contrast, in the ‘Penjar-Ramellet’ group, no clear separation linked to consumer preferences was observed between modern and traditional varieties. In fact, the modern variety PdP and the landrace DEC were both associated with ‘odor liking_on raw’ and ‘overall liking_on bread’; the least appreciated variety was the landrace PEN1. This latter variety received the lowest scores for ‘aspect liking_on raw’ and ‘overall liking-spreadability_on bread’ and for the sensory descriptors ‘color intensity’ (raw and on bread), ‘shiriveling_on raw’ and ‘seeds_on bread’. Several studies have compared the sensory profiles and/or the sensory-related instrumental traits of modern and traditional tomato varieties for fresh consumption [14,15,18,27,62,63,64], and in some cases, the traditional varieties have shown better properties [18,64]. However, this trend cannot be generalized because it can depend on the intra-landrace genetic variation and the choice of the modern varieties used in the comparison, which are often the result of successful breeding programs [15].
5. Conclusions and Future Work
The results obtained in this study showed that ‘Piennolo’ and ‘Penjar-Ramellet’ varieties lost their corresponding peculiar phenotypes in terms of physicochemical properties and postharvest behavior when not grown in their original agro-environmental conditions.
Sensory description by a trained panel of the raw and culinary preparations of both LSL tomato groups highlighted different sensory profiles. A reduction in sensory diversity among the genotypes was observed in the ‘Piennolo’ group for the baked tomatoes compared to the raw products, while this trend was not observed in the ‘Penjar-Ramellet‘ group. Cooking at high temperature (215 °C) by itself, modifying the consistency and chemical composition, could flatten the perceptible differences in the raw products.
These results point out the importance of studying sensory profiles using a culinary preparation as close as possible to that used by consumers (i.e., baked tomatoes, tomato spread on bread), as the results can be very different if they are studied on raw fruits. The participation of chefs and the inclusion of culinary traits in sensory studies can improve the efficiency of breeding programs [65].
Finally, hedonic tests conducted on both raw and culinary products revealed that sensory attributes driving consumer acceptance are specific to the ‘Piennolo’ and ‘Penjar-Ramellet’ genotypes. However, none of the tested varieties were associated with all the hedonic judgments, suggesting the need to develop breeding programs to obtain LSL tomato genotypes that fulfill consumer preferences.
Conceptualization, M.C., F.S., J.C. and S.G.; methodology, F.S., M.C., J.C., and S.G.; formal analysis, F.S. and J.C.; investigation, F.S., M.C., M.P., C.P., R.R.d.C., E.S.C., A.V., J.C. and S.G.; resources, A.G.; data curation, F.S., C.P., J.C. and M.C.; writing—original draft preparation, M.C., F.S., J.C. and S.G.; writing—review and editing, M.C., F.S., J.C., S.G. and A.G.; supervision, J.C. and S.G.; funding acquisition, A.G. All authors have read and agreed to the published version of the manuscript.
This study was approved for the two countries by the CNR Research Ethics and Integrity Committee (IRB, Prot. N. 0070284/2021).
The data that support the findings of this study are available from the corresponding authors upon reasonable request.
The authors acknowledge the service provider Adacta International (in Italy) for the recruitment of the participants in the consumer study. The authors also wish to express their gratitude to the sensory panel of CREA (Research Centre for Food and Nutrition), of Balandran CTIFL and of Barcelona School of Agricultural Engineering for carrying out the descriptive analysis of the tomato cultivars. We are grateful to Patrizia Spigno and Riccardo Riccardi (Arca 2010 Srl) for the kind assistance in field experiments.
The authors declare no conflict of interest.
Footnotes
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Enlarge this image.Figure 1. Fruit weight (FW), soluble solids content (SSC), firmness (FIRM) and fruit external color CIELAB coordinates (L*, a*, b*) of the ‘Penjar-Ramellet’ and ‘Piennolo’ varieties grown under low input and no irrigation in Italy (ITA) and high input and full irrigation in Spain (SP) (see Table 1), evaluated at harvest (T0). For each variable, different letters indicate significant differences (Tukey’s test, p < 0.05; ns, not significant).
Enlarge this image.Figure 2. Shelf-life (% sound fruits left) at 2 months postharvest of the ‘Piennolo’ and ‘Penjar-Ramellet’ varieties grown in Spain. Variety codes are listed in Table 1. Different letters indicate significant differences at p < 0.05 (Tukey’s HSD test).
Enlarge this image.Figure 3. Evolution of the fruit external color CIELAB coordinates L*(A), a* (B), b*(C) from harvest (T0) to the time sensory analyses were conducted in each country (T2 = 4.5 months in Italy, 3 months in Spain). Penjar_SP: ‘Penjar-Ramellet’ varieties grown in Spain; Piennolo_ITA: ‘Piennolo’ varieties grown in Italy. Comparisons between T0 and T2 were assessed using the Mann–Whitney–Wilcoxon (MWW) pairwise test. Significance levels: ** p < 0.01, **** p < 0.0001; ns, not significant.
Enlarge this image.Figure 4. Principal component analysis (PCA) Bi-plot of the physicochemical, sensory and consumers’ liking data of the raw and baked products of the five ‘Piennolo’ varieties tested in Italy (ACA, LUC, PAT, RSV, GBO). Sensory descriptors evaluated on the raw products are indicated in bold italics; sensory descriptors evaluated on the baked products are indicated in underlined italics and with a _B; consumers’ hedonic judgments are indicated in red (_R = raw; _B = baked). Traditional varieties are shown in red, while the commercial counterpart is indicated in blue. Physicochemical parameters evaluated on raw products: FW = fruit weight, FIRM = firmness; CIEL*a*b* coordinates (L*, a*, b*) and the color indices (C* and ho); SSC = soluble solids content, TA = titratable acidity, SHR = shriveling, TI = taste index. Variety codes are listed in Table 1.
Enlarge this image.Figure 5. Principal component analysis (PCA) Bi-plot of sensory attributes and consumers liking data of the raw and processed products of the five ‘Penjar-Ramellet’ varieties tested in Spain (DEC, PEN1, RAM, PdP, 545). Sensory descriptors evaluated on the raw products are indicated in bold italics; sensory descriptors evaluated on bread are indicated in italics underlined and with a_B; consumers’ hedonic judgments are indicated in red (_R = raw; _B = on bread). Traditional varieties are indicated in red, while modern varieties are indicated in blue. Variety codes are listed in Table 1.
List of LSL tomato varieties (Traditional and Modern/Commercial counterparts) analyzed in Italy and Spain.
| Variety | TRADITOM Pedigree N. | Code | Varietal a Group | Origin/Seed Company | Tested in Italy | Tested in Spain |
|---|---|---|---|---|---|---|
| Acampora | TRPO0040 | ACA | T | Campania (ITA) | √ | √ |
| Riccia San Vito | TRPO0130 | RSV | T | Campania (ITA) | √ | |
| Lucariello | TRPO0140 | LUC | T | Campania (ITA) | √ | √ |
| Patanara | TRPO0160 | PAT | T | Campania (ITA) | √ | √ |
| Gran Borghese | TRMC0470 | GBO | M (OP) | Four Sementi (ITA) | √ | √ |
| Ramellet | TRBA1140 | RAM | T | Balearic Islands (SP) | √ | √ |
| Penjar | TRCA0860 | PEN1 | T | Catalonia (SP) | √ | |
| Penjar | TRCA1060 | PEN2 | T | Catalonia (SP) | √ | |
| De colgar | TRVA0030 | DEC | T | Valencia (SP) | √ | √ |
| Palamós de Penjar | TRMC0540 | PdP | M (Hyb) | Semillas Fitó (SP) | √ | √ |
| 545 | N/A | 545 | M (Hyb) | Semillas Fitó (SP) | √ |
a T = Traditional; M = Modern/Commercial; OP = open pollinated; Hyb = hybrid; ITA = Italy; SP = Spain.
Description of sensory attributes used for sensory evaluation of raw fruit in Italy (continuous 0–9 scale) and in Spain (continuous 0–10 scale), and olfactory notes (qualitative measure, presence/absence).
| Category | Sensory |
Definition | Endpoint Labels | Italy | Spain | |
|---|---|---|---|---|---|---|
| Appearance | Color intensity | Visual examination of the tomato placed on the peduncular side. For tomatoes with a color other than red (green, orange, yellow, pink, streaked, etc.), this criterion was not scored | light red | full red | √ | √ |
| Shriveling | Wrinkling due to loss of moisture | not at all | completely | √ | √ | |
| Seeds | Amount of seeds in the internal locular portion | none | many | √ | √ | |
| Texture | Resistance to cut | Resistance of tomato flesh to penetration with a knife | no resistance | high resistance | √ | √ |
| Olfactory | Overall odor | Overall impression perceived by receptors of the olfactory system (via ortho-nasal) after cutting | weak | strong | √ | √ |
| Green odor | Odor resembling green vegetables, grass, stalk, leaf | weak | strong | √ | √ | |
| Ripe odor | Odor of tomato at full ripeness | weak | strong | √ | √ | |
| In-mouth evaluation | Sweet taste | Basic taste produced by sugars (e.g., fructose or glucose) | weak | strong | √ | |
| Acid taste | Basic taste produced by organic acids (e.g., citric or malic acids) | weak | strong | √ | ||
| Off-Flavor | Presence of aromatic compounds not characteristic of ripe tomato (e.g., decaying vegetation, metallic, chemical) | null | strong | √ | ||
|
Qualitative measure
|
||||||
| Pea, legume odor | yes | no | √ | √ | ||
| Herbaceous odor | yes | no | √ | √ | ||
| Stem (stalk, tomato leaf) odor | yes | no | √ | √ | ||
| Floral odor | yes | no | √ | √ | ||
| Fruity odor | yes | no | √ | √ | ||
| Baked tomato (over ripe, tomato paste, tomato juice/sauce) odor | yes | no | √ | √ | ||
| Undergrowth (hearty, musty, humus, mushroom) odor | yes | no | √ | √ | ||
| Diacetyl-like odor | yes | no | √ | √ | ||
| Other odor (to be specified) | ||||||
Description of sensory attributes used for sensory evaluation of tomato fruit processed according to the culinary tradition of Italy (baked) (continuous 0–9 scale), and flavor notes (qualitative measure, presence/absence).
| Category | Sensory Attribute | Definition | Endpoint Labels | |
|---|---|---|---|---|
| Olfactory | Overall odor | Intensity of the overall olfactory impression perceived via ortho-nasal | weak | strong |
| Baked tomato odor | Ortho-nasal olfactory intensity sensation of baked tomato | weak | strong | |
| In-mouth evaluation | ||||
| with the skin | Sweet taste | Basic taste sensation caused by sugars (e.g., sucrose) | weak | strong |
| Bitter taste | Basic taste caused by bitter substances (e.g., quinine) | weak | strong | |
| Overall flavor | Intensity of overall olfactory sensations perceived retro-nasally while chewing | weak | strong | |
| Baked tomato flavor | Retro-nasal olfactory sensation of baked tomato | weak | strong | |
| Hardness | Tactile characteristic of hard and thick skin perceived through mechanical and tactile receptors | tender | hard | |
| Bitter persistence (after swallowing) a,b | Basic taste persisting in the mouth after the substance that caused it is no longer present a,b | brief | long-lasting | |
| after removing the skin | Sweet taste | Basic taste sensation caused by sugars (e.g., sucrose) | weak | strong |
| Salty taste | Basic taste sensation caused by inorganic salts (e.g., sodium chloride) | weak | strong | |
| Acid taste | Basic taste sensation caused by acid substances (e.g., citric acid) | weak | strong | |
| Bitter taste | Basic taste caused by bitter substances (e.g., quinine) | weak | strong | |
| Overall flavor | Intensity of the overall olfactory impression perceived via retro-nasal | weak | strong | |
| Baked tomato flavor c,d | Retro-nasal olfactory sensation of baked tomato | weak | strong | |
Qualitative measure (presence/absence). a Skin-astringency: yes, no. b Skin-metallic: yes, no. c Pea, legume: yes, no. d Green, unripe (unripe fruit, grass, cut grass): yes, no.
Description of sensory attributes used for sensory evaluation of tomato fruit processed according to the culinary tradition of Spain (spread on bread) (continuous 0–10 scale).
| Category | Sensory Attribute | Definition | Endpoint Labels | |
|---|---|---|---|---|
| Olfactory | Overall odor | Intensity of the overall olfactory impression perceived via ortho-nasal | weak | strong |
| In-mouth evaluation | Sweet taste (on bread) | Basic taste produced by sugars (e.g., fructose or glucose) | weak | strong |
| Acid taste (on bread) | Basic taste produced by organic acids (e.g., citric or malic acids) | weak | strong | |
| Dish preparation | Spreadability (on bread) | Amount of bread (surface) that can be rubbed by one half of the fruit | low | high |
| Seeds (on bread) | Visual impression of the presence of seeds on the bread | none | many | |
| Color intensity (on bread) | Visual impression of the intensity of red color of the bread | light red | full red | |
| Overall flavor | Intensity of the overall olfactory impression perceived via retro-nasal | weak | strong | |
Supplementary Materials
The following supporting information can be downloaded at:
References
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; Peparaio, Marina 2 ; Pons, Clara 3 ; Roser Romero del Castillo 4
; Civitelli, Eleonora Saggia 2 ; Vitiello, Antonella 1 ; Granell, Antonio 3
; Casals, Joan 4
; Grandillo, Silvana 1
1 Institute of Biosciences and Bioresources (IBBR), Research Division Portici, National Research Council of Italy (CNR), Via Università 133, 80055 Portici, Italy;
2 Research Centre for Food and Nutrition, Council for Agricultural Research and Economics (CREA), Via Ardeatina 546, 00178 Roma, Italy;
3 Instituto de Biología Moleculary Celular de Plantas (IBMCP), Consejo Superior de Investigaciones Científicas (CSIC), Universitat Politècnica de València, 46022 València, Spain;
4 HorPTA, Department of Agri-Food Engineering and Biotechnology, Campus Baix Llobregat, Polytechnic University of Catalonia-BarcelonaTech, Esteve Terrades, 8, 08860 Castelldefels, Spain;