Effect of Home-Cooking Methods on Phenolic Composition and Antioxidant Activity of Sweetpotato (Ipomoea batatas (L.) Lam.) Cultivars Grown in Egypt

Ateea A. Bellail, Omayma E. Shaltout, Mohammed M. Youssef, Ahmed M. A. El Gamal

Food Science Department, Faculty of Agriculture (Saba-Basha), Alexandria University, Alexandria, Egypt.
Food Technology Department, Faculty of Agriculture (El-Shatby), Alexandria University, Alexandria, Egypt.
Plant Production Department, Faculty of Agriculture (Saba-Bacha), Alexandria University, Alexandria, Egypt..

DOI: 10.4236/fns.2012.34069                

Abstract

Four sweetpotato (Ipomoea batatas (L.) Lam.) cultivars grown in Alexandria, Egypt, including Monofya 6, Monofya 66, Abeeis, and Beauregard were cooked using four different home-cooking methods (boiling, baking, microwaving, and deep-frying). The antioxidant contents (total phenolics by Folin-Denis, and individual phenolic acids by HPLC) as well as the antioxidant activity determined by reducing power (RP), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and 2,2’-azinobis(3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS) were measured in this study. Results indicated that total phenolic contents of raw flesh tissue by Folin-Denis ranged from 0.53 to 0.87 mg chlorogenic acid equivalent (mg ChAE)/g dry weight basis (dw). The RP ranged between 0.1 and 0.25 mg ChAE/g dw, DPPH and ABTS radical scavenging activities varied from 1.10 to 1.72 and 0.85 to 1.51 μmol trolox equivalent (TE)/g dw, respectively. Thermal processing significantly (P ≤ 0.05) increased the total phenolic content, as well as individual phenolic acids and antioxidant capacity of all the cultivars under study. In this respect, deep-frying exhibited the highest increment among the four processing methods. The most abundant individual phenolic acids in processed flesh roots tissues were chlorogenic acid followed by 3,5-dicaffeoylquinic acid. Total phenolic contents were highly correlated with RP, DPPH, and ABTS, also the correlation between the DPPH and ABTS values were significantly high.

Keywords

Sweetpotato; Total Phenolics; Antioxidant Activity; Chlorogenic Acid; Thermal Processing; HPLC

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	G. Padmaja, “Uses and Nutritional Data of Sweetpotato,” In: G. Loebenstein and G. Thottappilly, Eds., The Sweetpotato, Springer, Dordrecht, 2009, pp. 189-234. doi:10.1007/978-1-4020-9475-0_11
[2]	B. N. Ames, M. K. Shigenaga and T. M. Hagen, “Oxidants, Antioxidants, and the Degenerative Diseases of Aging,” Proceedings of the National Academy of Sciences, Vol. 90, No. 17, 1993, pp. 7915-7922. doi:10.1073/pnas.90.17.7915
[3]	J. W. Anderson, B. M. Johnstone and M. E. Cook-Newell, “Meta-Analysis of the Effects of Soy Protein Intake on Serum Lipids,” New England Journal of Medicine, Vol. 333, No. 5, 1995, pp. 276-282. doi:10.1056/NEJM199508033330502
[4]	J. A. Joseph, D. F. Bielinski and D. R. Fisher, “Blueberry Treatment Antagonizes C-2 Ceramide-Induced Stress Signaling in Muscarinic Receptor-Transfected COS-7 Cells,” Journal of Agricultural and Food Chemistry, Vol. 58, No. 6, 2010, pp. 3380-3392. doi:10.1021/jf9039155
[5]	R. Kurata, M. Adachi, O. Yamakawa and M. Yoshimoto, “Growth Suppression of Human Cancer Cells by Polyphenolics from Sweetpotato (Ipomoea batatas L.) Leaves,” Journal of Agricultural and Food Chemistry, Vol. 55, No. 1, 2007, pp. 185-190. doi:10.1021/jf0620259
[6]	A. Scalbert, C. Manach, C. Morand, C. Rémésy and L. Jiménez, “Dietary Polyphenols and the Prevention of Diseases,” Critical Reviews in Food Science and Nutrition, Vol. 45, No. 4, 2005, pp. 287-306. doi:10.1080/1040869059096
[7]	G. O. Rudkin and J. M. Nelson, “Chlorogenic Acid and Respiration of Sweet Potatoes,” Journal of the American Chemical Society, Vol. 69, No. 6, 1947, pp. 1470-1475. doi:10.1021/ja01198a065
[8]	I. Uritani and M. Miyano, “Derivatives of Caffeic Acid in Sweet Potato Attacked by Black Rot,” Nature, Vol. 175, No. 4462, 1955, pp. 812-812. doi:10.1038/175812a0
[9]	W. M. Walter, A. E. Purcell and G. K. McCollum, “Use of High-Pressure Liquid Chromatography for Analysis of Sweet Potato Phenolics,” Journal of Agricultural and Food Chemistry, Vol. 27, No. 5, 1979, pp. 938-941. doi:10.1021/jf60225a031
[10]	F. Hayase and H. Kato, “Antioxidative Components of Sweet Potatoes,” Journal of Nutritional Science and Vitaminology (Tokyo), Vol. 30, No. 1, 1984, pp. 37-46. doi:doi:10.3177/jnsv.30.37
[11]	K.-C. Son, R. F. Severson, M. E. Snook and S. J. Kays, “Root Carbohydrate, Organic Acids, and Phenolic Chemistry in Relation to Sweetpotato Weevil Resistance,” HortScience, Vol. 26, No. 10, 1991, pp. 1305-1308.
[12]	D. P. Thompson, “Chlorogenic Acid and Other Phenolic Compounds in Fourteen Sweet Potato Cultivars,” Journal of Food Science, Vol. 46, No. 3, 1981, pp. 738-740. doi:10.1111/j.1365-2621.1981.tb15338.x
[13]	M. Yoshimoto, R. Kurata-Azuma, M. Fujii, D.-X. Hou, K. Ikeda, T. Yoshidome and M. Osako, “Phenolic Composition and Radical Scavenging Activity of SweetpotatoDerived Shochu Distillery By-Products Treated with Koji,” Bioscience, Biotechnology, and Biochemistry, Vol. 68, No. 12, 2004, pp. 2477-2483. doi:10.1271/bbb.68.2477
[14]	J.-K. Jung, S.-U. Lee, N. Kozukue, C. E. Levin and M. Friedman, “Distribution of Phenolic Compounds and Antioxidative Activities in Parts of Sweet Potato (Ipomoea batata L.) Plants and in Home Processed Roots,” Journal of Food Composition and Analysis, Vol. 24, No. 1, 2011, pp. 29-37. doi:10.1016/j.jfca.2010.03.025
[15]	M. S. Padda and D. H. Picha, “Quantification of Phenolic Acids and Antioxidant Activity in Sweet Potato Genotypes,” Scientia Horticulturae, Vol. 119, No. 1, 2008, pp. 17-20. doi:10.1016/j.scienta.2008.07.008
[16]	M. Takenaka, K. Nanayama, S. Isobe and M. Murata, “Changes in Caffeic Acid Derivatives in Sweet Potato (Ipomoea batatas L.) during Cooking and Processing,” Bioscience, Biotechnology, and Biochemistry, Vol. 70, No. 1, 2006, pp. 172-177. doi:10.1271/bbb.70.172
[17]	V. D. Truong, R. F. McFeeters, R. T. Thompson, L. L. Dean and B. Shofran, “Phenolic Acid Content and Composition in Leaves and Roots of Common Commercial Sweetpotato (Ipomea batatas L.) Cultivars in the United States,” Journal of Food Science, Vol. 72, No. 6, 2007, pp. C343-C349. doi:10.1111/j.1750-3841.2007.00415.x
[18]	W. M. Walter and A. E. Purcell, “Evaluation of Several Methods for Analysis of Sweet Potato Phenolics,” Journal of Agricultural and Food Chemistry, Vol. 27, No. 5, 1979, pp. 942-946. doi:10.1021/jf60225a030
[19]	B. A. Cevallos-Casals and L. Cisneros-Zevallos, “Stoichiometric and Kinetic Studies of Phenolic Antioxidants from Andean Purple Corn and Red-Fleshed Sweetpotato,” Journal of Agricultural and Food Chemistry, Vol. 51, No. 11, 2003, pp. 3313-3319. doi:10.1021/jf034109c
[20]	T. Oki, M. Masuda, S. Furuta, Y. Nishiba, N. Terahara and I. Suda, “Involvement of Anthocyanins and Other Phenolic Compounds in Radical-Scavenging Activity of Purple-Fleshed Sweet Potato Cultivars,” Journal of Food Science, Vol. 67, No. 5, 2002, pp. 1752-1756. doi:10.1111/j.1365-2621.2002.tb08718.x
[21]	I. O. Rabah, D.-X. Hou, S.-I. Komine and M. Fujii, “Potential Chemopreventive Properties of Extract from Baked Sweet Potato (Ipomoea batatas Lam. Cv. Koganesengan),” Journal of Agricultural and Food Chemistry, Vol. 52, No. 23, 2004, pp. 7152-7157. doi:10.1021/jf049368w
[22]	R. L. Prior, X. Wu and K. Schaich, “Standardized Methods for the Determination of Antioxidant Capacity and Phenolics in Foods and Dietary Supplements,” Journal of Agricultural and Food Chemistry, Vol. 53, No. 10, 2005, pp. 4290-4302. doi:10.1021/jf0502698
[23]	F. Rautenbach, M. Faber, S. Laurie and R. Laurie, “Antioxidant Capacity and Antioxidant Content in Roots of 4 Sweetpotato Varieties,” Journal of Food Science, Vol. 75, No. 5, 2010, pp. C400-C405. doi:10.1111/j.1750-3841.2010.01631.x
[24]	S. Furuta, I. Suda, Y. Nishiba and O. Yamakawa, “High tert-Butylperoxyl Radical Scavenging Activities of Sweet Potato Cultivars with Purple Flesh,” Food Science and Technology International, Vol. 4, No. 1, 1998, pp. 33-35. doi:10.3136/fsti9596t9798.4.33
[25]	Y.-C. Huang, Y.-H. Chang and Y.-Y. Shao, “Effects of Genotype and Treatment on the Antioxidant Activity of Sweet Potato in Taiwan,” Food Chemistry, Vol. 98, No. 3, 2006, pp. 529-538. doi:10.1016/j.foodchem.2005.05.083
[26]	M. S. Padda and D. H. Picha, “Phenolic Composition and Antioxidant Capacity of Different Heat-Processed Forms of Sweetpotato cv. ‘Beauregard’,” International Journal of Food Science & Technology, Vol. 43, No. 8, 2008, pp. 1404-1409. doi:10.1111/j.1365-2621.2007.01663.x
[27]	T. Swain and W. E. Hillis, “The Phenolic Constituents of Prunus Domestica. I.—The Quantitative Analysis of Phenolic Constituents,” Journal of the Science of Food and Agriculture, Vol. 10, No. 1, 1959, pp. 63-68. doi:10.1002/jsfa.2740100110
[28]	M. S. Padda and D. H. Picha, “Methodology Optimization for Quantification of Total Phenolics and Individual Phenolic Acids in Sweetpotato (Ipomoea batatas L.) Roots,” Journal of Food Science, Vol. 72, No. 7, 2007, pp. C412-C416. doi:10.1111/j.1750-3841.2007.00448.x
[29]	C. F. R. Ferreira, P. Baptista, M. Vilas-Boas and L. Barros, “Free-Radical Scavenging Capacity and Reducing Power of Wild Edible Mushrooms from Northeast Portugal: Individual Cap and Stipe Activity,” Food Chemistry, Vol. 100, No. 4, 2007, pp. 1511-1516. doi:10.1016/j.foodchem.2005.11.043
[30]	W. Brand-Williams, M. E. Cuvelier and C. Berset, “Use of a Free Radical Method to Evaluate Antioxidant Activity,” Lebensmittel-Wissenschaft and Technologie, Vol. 28, No. 1, 1995, pp. 25-30. doi:10.1016/S0023-6438(95)80008-5
[31]	N. J. Miller and C. A. Rice-Evans, “Factors Influencing the Antioxidant Activity Determined by the ABTS?+ Radical Cation Assay,” Free Radical Research, Vol. 26, No. 3, 1997, pp. 195-199. doi:10.3109/10715769709097799
[32]	L. E. Steed and V. D. Truong, “Anthocyanin Content, Antioxidant Activity, and Selected Physical Properties of Flowable Purple-Fleshed Sweetpotato Purees,” Journal of Food Science, Vol. 73, No. 5, 2008, pp. S215-S221. doi:10.1111/j.1750-3841.2008.00774.x
[33]	C. C. Teow, V. Truong, R. F. McFeeters, R. L. Thompson, K. V. Pecota and G. C. Yencho, “Antioxidant Activities, Phenolic and β-Carotene Contents of Sweet Potato Genotypes with Varying Flesh Colours,” Food Chemistry, Vol. 103, No. 3, 2007, pp. 829-838. doi:10.1016/j.foodchem.2006.09.033