Nutritional evaluation of baby corn (zea mays)

Abstract

Purpose - The purpose of this paper is to study nutritional composition of HM-4 variety of baby corn. Design/methodology/approach - Baby corn was analysed for proximate composition, available carbohydrates, dietary fiber constituents, in vitro digestibility, minerals, anti-nutrients, vitamin and amino acids. Findings - Baby corn contained 90.03, 17.96, 2.13, 5.30 and 5.89 percent moisture, protein, fat, ash and crude fibre, respectively. Total soluble sugars content was 23.43 g/100 gm and reducing sugars was 1.96 g/100 g. It contained 8.10 g/100 g of cellulose and 5.41 g/100 g of lignin. In vitro starch and protein digestibility was 28.80 mg maltose released per gram and 72.18 percent, respectively. Baby corn contained 5.43 mg/100 g of ascorbic acid and 670 μg/100 g of ß-carotene. Calcium, magnesium and phosphorus content of baby corn was 95.00, 345.00 and 898.62 mg/100 g, respectively, baby corn contained 0.05, 2.85 and 0.675μg/g of methionine, isoleucine and leucine, respectively. Originality/value - The study indicated that baby corn is good source of various nutrients like protein, crude fibre, carbohydrates and dietary fibres and its nutritional quality is at par or even superior to many other commonly used vegetables.

1 Introduction

Baby corn (Zea mays ) is the ear, harvested young, when the silks have either not emerged or just emerged and no fertilization has taken place. Baby corn besides being delicious and nutritious, is a valuable and attractive product in both national and international market. Baby corn may be consumed as raw or used as an ingredient in various preparations like soups, deep fried with meat or rice, sauted with other vegetables, pickles, etc. The nutritive value of baby corn is comparable to several high-priced vegetables like cauliflowers, cabbage, french beans, spinach, lady finger, brinjal, tomato, radish, etc. ([8] Paroda, 2001). Baby corn, a new vegetable not so popular yet, is an emerging potential crop among the progressive farmers around big cities. There is very less information available about the nutritional composition of baby corn. Hence, the present study was carried out to evaluate the nutritional potentials of baby corn.

2 Materials and methods

Sample of baby corn cultivar HM-4 was procured from the experimental farms at Regional Research Station, CCS HAU, Uchani, Karnal. Baby corn was cleaned off the husk material and chopped into small pieces and dried in the oven at 50°C till moisture free and then ground in an electric grinder and packed in air tight polypacks for further analysis. The sample was than analyzed for various nutritional parameters. Proximate compositions, ascorbic acid and ß-carotene were estimated using the standard method of analysis ([1] AOAC, 1995). Total soluble sugars were estimated by the method of [19] Yemm and Willis (1954) and reducing sugars by [14] Somogyi's (1945) modified method. Non-reducing sugars were calculated by difference. Starch and dietary fibre constituents were estimated by the method of [3] Clegg (1956) and [16] Van Soest and Wine (1967), respectively. In vitro protein and starch digestibility were estimated by method given by [7] Mertz et al. (1983) and [13] Singh et al. (1982), respevtively. Calcium, iron, zinc and magnesium were determined from acid digested sample by atomic absorption spectrophotometer 2380, Perkin Elmer (USA) according to the method of [6] Lindsey and Norwell (1969) and phosphorus was determined colorimetrically by the method of [2] Chen et al. (1956). Minerals were extracted in 0.03N HCl following the method of [9] Peterson et al. (1943). Phytic acid and tannins were determined by the method of [4] Davies and Reid (1979) and [12] Singh and Jambunathan (1981), respectively. Amino acids were analysed by HPLC technique by the method given by [15] Tarr (1989).

3 Results and discussions

3.1 Proximate composition

The results obtained for the proximate composition are depicted in Table I [Figure omitted. See Article Image.].

3.1.1 Moisture

Baby corn contained 90.03 percent moisture on fresh matter basis. [20] Yodpetch (1979) also reported 89.10 percent moisture in baby corn.

3.1.2 Crude protein

Crude protein content of baby corn was 17.90 g/100 g. Baby corn was observed to have a similar or slightly higher protein content than vegetables like cabbage (1.80 g/100 g), bitter gourd (1.60 g/100 g), brinjal (1.40 g/100 g), french beans (2.00 g/100 g) and spinach (1.90 g/100 g) as observed by [5] Gopalan et al. (1989).

3.1.3 Crude fat

Baby corn contained 2.13 g/100 g crude fat which was similar to commonly used vegetables like bitter gourd and ladies finger ([5] Gopalan et al. , 1989) and higher than tomato ([17] Vashisht, 1998), amaranthus leaves ([10] Punia et al. , 2004), cabbage and french beans ([5] Gopalan et al. , 1989).

3.1.4 Total ash

Total ash content of baby corn was 5.30 g/100 g which was higher than brinjal (0.30 g/100 g), cucumber (0.30 g/100 g), french beans (0.50 g/100 g) and green papaya (0.50 g/100 g) ([5] Goplan et al. , 1989).

3.1.5 Crude fibre

Baby corn contained 5.89 g/100 g of crude fibre which was higher than many common vegetables like lettuce, radish, spinach, bottle gourd, colocasia stem and ridge gourd ([5] Goplan et al. , 1989).

3.2 Available carbohydrates

Total soluble sugars and reducing sugars content was found to be 23.43 and 1.96 g/100 g, respectively. Non-reducing sugars content was 21.47 g/100 g. Baby corn contained comparatively less total soluble and reducing sugars and higher non-reducing sugar than tomato ([17] Vashisht, 1998) and cucumber ([18] Verma, 2000). Starch content of baby corn was 15.60 g/100 g (Table II [Figure omitted. See Article Image.]).

3.3 Dietary fibre constituents

Neutral detergent fibre and acid detergent fibre were found to be 27.12 g/100 g and 2.08 g/100 g, respectively. Hemicellulose and cellulose content was 25.04 and 8.10 g/100 g, respectively, whereas lignin content was 5.41 g/100 g (Table III [Figure omitted. See Article Image.]).

3.4 In vitro digestibility

In vitro protein digestibility of baby corn was found to be 72.18 percent and in vitro starch digestibility was 28.80 mg maltose released per gram (Table IV [Figure omitted. See Article Image.]).

3.5 Minerals

3.5.1 Total minerals

Calcium content of baby corn was 95.00 mg/100 g. Baby corn, when compared to other vegetables, thus contained calcium higher than tomato ([17] Vashisht, 1998); bitter gourd ([11] Sethi et al. , 2003); cabbage, lettuce, carrot, colocasia, radish, cucumber, brinjal and bitter gourd ([5] Gopalan et al. , 1989). Baby corn contained 6.91 mg/100 g of iron which was observed to be higher than a number of common vegetables like bitter gourd (0.61 mg/100 g), brinjal (0.38 mg/100 g), french beans (0.61 mg/100 g) and ladies finger (0.35 mg/100 g) as reported by [5] Gopalan et al. (1989). Baby corn contained 898.62 mg/100 g phosphorus which was found to be several times higher than the phosphorus content of cabbage, lettuce, spinach, bitter gourd, brinjal, cauliflower, french beans and ladies finger which are reported to have 44.00, 28.00, 26.00, 10.00, 47.00, 57.00, 28.00 and 56.00 mg phosphorus/100 g, respectively, ([5] Goplan et al. , 1989). Similar findings about higher phosphorus content were reported by [20] Yodpetch (1979). Baby corn contained 345.00 mg/100 g of magnesium and 6.25 mg/100 g of zinc (Table V [Figure omitted. See Article Image.]).

3.5.2 HCl-extractable minerals

HCl-extractable calcium, magnesium, zinc, iron and phosphorus content of baby corn was 38.67, 124.00, 4.94, 6.16 and 709.66 mg/100 g, respectively, (Table V [Figure omitted. See Article Image.]).

3.6 Anti-nutrients

Baby corn contained 398 mg/100 g of tannins and 275 mg/100 g of phytic acid (Table VI [Figure omitted. See Article Image.]).

3.7 Vitamin

Ascorbic acid and ß-carotene content of baby corn was 5.43 mg/100 g and 670.00 μg/100 g, respectively, (Table VII [Figure omitted. See Article Image.]).

Baby corn thus can supply ascorbic acid higher than carrot, colocasia stem, pumpkin and ridge gourd which supply 3.00, 3.00, 2.00 and 5.00 mg ascorbic acid/100 g, respectively, ([5] Gopalan et al. , 1989).

3.8 Amino acids

Methionine, lsoleucine, leucine, lysine and phenylalanine content of baby corn was 0.05, 2.85, 0.675, 0.225 and 0.3 μg/g, respectively, and tryphtophan was not detectable. Alanine, serine, arginine, glycine, aspergine, glutamine and threonine content were in the range of 1.075 to 3.65 μg/g whereas tyrosine, histidine and valine were in the range of 0.20 to 0.85 μg/g (Table VIII [Figure omitted. See Article Image.]).

4 Conclusions

The results of study indicated that baby corn is highly nutritive and its nutritional quality is at par or even superior to some of the seasonal vegetables like tomato, cabbage, lettuce, carrot, colocasia, radish cucumber, brinjal and bitter gourd. Besides protein, vitamins and iron, it is one of the richest source of phosphorus.

References

1. AOAC (1995), Official Methods of Analysis of the Association of Official Agricultural Chemists, Association of Analytical Chemists, Washington, DC, pp. 125-39.

2. Chen, P.S., Tosibara, T.Y. and Warner, H. (1956), "Micro-determination of phosphorus", Anal. Chem., Vol. 28, pp. 1756-9.

3. Clegg, K.M. (1956), "The application of anthrone reagent to the estimation of starch incereals", J. Sci. Food Chem. Agric., Vol. 7, pp. 40-4.

4. Davies, N.T. and Reid, H. (1979), "An evaluation of phytate, zinc, copper, iron, and manganese contents, availability of soya based textured vegetable protein meat substitutes or meat extrudes", Br. J. Nutr., Vol. 41, p. 579.

5. Gopalan, C., Rama Sastri, B.V., Balasubramanian, S.C., Narasinga Rao, B.S., Doesthale, Y.G. and Pant, K.C. (1989), Nutritive value of Indian Foods, National Institute of Nutrition, ICMR, Hyderabad.

6. Lindsey, W.L. and Norwell, M.A. (1969), "A new DPTA-TEA soil test for zinc and iron", Agron. Abst., Vol. 61, p. 48.

7. Mertz, E.T., Kirleis, A.W. and Sxtell, J.D. (1983), "In vitro digestibility of proteins in major food cereals", Fed. Proc., Vol. 42 No. 5, p. 6026.

8. Paroda, S. (2001), Bade kuposhan ka jawab nahni makka; Kheti, January, pp. 33-4.

9. Peterson, W.H., Skinner, J.T. and Strong, F.M. (1943), Elements of Food Biochemistry, Prentice-Hall, New York, NY, p. 73.

10. Punia, D., Yadav, S.K., Gupta, M. and Khetarpaul, N. (2004), "Nutrient composition of amaranth (Amaranthus tricolor) and kondhra (Digeria arvensis) leaves and their products", J. Food Sci. Technol., Vol. 41 No. 5, pp. 563-5.

11. Sethi, V., Singh, G. and Singh, J. (2003), "Effect of drying methods on mineral content of bitter gourd", Indian Food Packer, Vol. 57 No. 5, pp. 74-6.

12. Singh, U. and Jambunathan, R. (1981), "Studies on desi and kabuli chickpea (Cicer arietinum L.) cultivars. Levels of protease inhibitors, levels of polyphenolic components and in vitro protein digestibility", J. Food Sc., Vol. 46, pp. 1364-7.

13. Singh, U., Khedekar, M.S. and Jambunathan, R. (1982), "Studies on desi kabuli chickpea cultivars. The level of amylase inhibitors, levels of oligosaccharides and in vitro starch digestibility", J. Food Sc., Vol. 47, p. 510.

14. Somogyi, M. (1945), "A new reagent for the determination of sugar", J. Biol. Chem., Vol. 160, pp. 61-6.

15. Tarr, G.E. (1981), "Conditions for optimal separation of phenylthiohydantoin amino acids", Annals of Biochemistry, Vol. 111, p. 27.

16. Van Soest, P.I. and Wine, R.H. (1967), "Use of detergents in the analysis of fibrous foods. Determination of plant cell wall constituents", J. Assoc. Off. Anal. Chem., Vol. 50, pp. 50-1.

17. Vashisht, A. (1998), "Development of ready-to-drink tomato juice and instant soup from newly evolved tomato cultivars", MSc thesis, CCS Haryana Agricultural University, Hisar.

18. Verma, S. (2000), "Nutritional evaluation and utilization of pumpkin", MSc thesis, CCS Haryana Agricultural University, Hisar.

19. Yemm, E.W. and Willis, A.J. (1954), "The estimation of carbohydrates in plant extracts by anthrone", Biochem. J., Vol. 57, pp. 508-14.

20. Yodpetch, C. (1979), "Studies on sweet corn as potential young cob corn (Zea mays L.)", PhD thesis, University of Philippines, Quezon City.

Appendix

Corresponding author

Santosh Hooda can be contacted at: [email protected]

  

Illustration

Table I: Proximate composition of baby corn (dry matter basis)

  

Table II: Available carbohydrate content of baby corn (dry matter basis)

  

Table III: Dietary fibre content of baby corn (dry matter basis)

  

Table IV: In vitro starch and protein digestibility content baby corn (on dry matter basis)

  

Table V: Total and HCl-extractable mineral content of baby corn (mg/100 g on dry matter basis)

  

Table VI: Anti-nutrients content of baby corn (on dry matter basis)

  

Table VII: Vitamin content of baby corn

  

Table VIII: Amino acid composition of baby corn (dry matter basis)