Physical, Chemical and Sensory Characterization of Deep-Fried Fresh-Cut Potatoes Coated with Hydrocolloid/Herbal Extracts

Abstract

Research backgroundRecently, natural plant extracts have been used to increase the nutritional value of food and to potentially reduce the absorbed fat and the formation of acrylamide in fried foods. Literature data on the use of edible polymers with nettle or olive leaf extracts are scarce. Experimental approachThe effect of novel coatings on colour, fat absorption, phenolic and sugar content, and acrylamide formation in deep-fat-fried fresh-cut potatoes was evaluated. Extracts of olive and nettle leaves were incorporated in carboxymethyl cellulose (CMC) and gum arabic, used as coatings for potatoes and applied before frying. This aimed to improve the nutritional quality of deep-fat-fried fresh-cut potatoes. Results and conclusionsEnrichment of the edible coatings with extracts resulted in a significant change in the visible colour of the potatoes before frying. Significant effect of the extract amount on the sensory characteristics of potatoes was also observed. Most importantly, the perception of characteristic potato odour and taste was not significantly affected by the coating. Although higher amounts of the extract (1.5%) resulted in higher phenolic mass fraction in fried potatoes, the sensory scores decreased. After frying, fat mass fraction in the coated potatoes was reduced by about 15% compared to the uncoated samples. The type of extract affected the total sugar mass fraction in fried potatoes, which was lower in the samples with coatings enriched with olive leaf than in those with nettle leaf. Only gum arabic coating had a reducing effect on acrylamide mass fraction by 17%. Based on all the obtained results, CMC and gum arabic coatings did not influence sensory properties, so they can be recommended as carriers of functional compounds or as a frying pre-treatment for potatoes with favourable effect on fat and acrylamide content. Novelty and scientific contributionThe knowledge obtained in this study can be exploited for preparation of coatings with functional compounds used as a pre-treatment for fried food with favourable effect on fat and acrylamide content.

Alternate abstract:

Pozadina istraživanja. Iako se prirodni ekstrakti iz biljaka posljednjih godina koriste za povećanje nutritivne vrijednosti hrane te moguće smanjenje apsorpcije masnoće i nastanka akrilamida u prženoj hrani, malo je podataka u literaturi o uporabi jestivih polimera s ekstraktima koprive ili lista masline. Eksperimentalni pristup. Procijenjen je učinak novih jestivih prevlaka na boju, upijanje masti, udjele fenola i šećera te nastanak akrilamida u svježe rezanom i prženom krumpiru. Ekstrakti lišća masline i koprive ugrađeni su u karboksimetilcelulozu i gumu arabiku te upotrijebljeni kao premazi za krumpir. Svrha je postupka bila poboljšati nutritivnu kakvoću svježe rezanog prženog krumpira. Rezultati i zaključci. Obrada krumpira jestivim prevlakama obogaćenim ekstraktima znatno je promijenila boju krumpira prije prženja. Također je uočen značajan utjecaj količine ekstrakta na senzorska svojstva krumpira. Prevlaka nije bitno utjecala na percepciju karakterističnog mirisa i okusa krumpira. Iako su veće količine ekstrakta (1,5 %) rezultirale većim udjelom fenola u prženim krumpirima, to je negativno utjecalo na senzorska svojstva. Nakon prženja, udjel masti u krumpirima s prevlakama smanjen je za otprilike 15 % u usporedbi s uzorcima bez prevlaka. Vrsta ekstrakta utjecala je na maseni udjel ukupnih šećera u prženom krumpiru, koji je bio niži u uzorcima s prevlakama obogaćenim listom masline nego u onima s listom koprive. Jedino je prevlaka od gume arabike smanjila maseni udjel akrilamida za 17 %. Na osnovi ukupnih rezultata može se zaključiti da karboksimetil celuloza i guma arabika nisu utjecale na senzorska svojstva, pa se mogu preporučiti kao nositelji funkcionalnih spojeva ili upotrijebiti za obradu krumpira prije prženja, što povoljno utječe na udjele masti i akrilamida u njima. Novost i znanstveni doprinos. Spoznaje dobivene ovim istraživanjem mogu se iskoristiti u pripremi prevlaka s funkcionalnim spojevima koje se koriste u prethodnoj obradi pržene hrane s povoljnim učinkom na udjele masti i akrilamida.