Antioxidant and α-Glucosidase Inhibitory Activity of Polyphenols in Peel and Core from Five Different Pear Varieties

Zhaohong Ci^{1, 2} and Michiyuki Kojima^{2, 3,}

¹Department of Food Science, Obihiro University of Agriculture and Veterinary Medicine, 11, Nishi-2-sen, Inada-machi, Obihiro, Hokkaido 080-8555, Japan

²United Graduate School of Agricultural Sciences, Iwate University, 3-18-8, Ueda, Morioka, Iwate 020-8550, Japan

³Department of Human Sciences, Obihiro University of Agriculture and Veterinary Medicine, 11, Nishi-2-sen, Inada-machi, Obihiro, Hokkaido 080-8555, Japan

Cite this paper:
Zhaohong Ci and Michiyuki Kojima. Antioxidant and α-Glucosidase Inhibitory Activity of Polyphenols in Peel and Core from Five Different Pear Varieties. Journal of Food and Nutrition Research. 2018; 6(9):546-550. doi: 10.12691/jfnr-6-9-1

Abstract

This study was performed to compare polyphenol content, DPPH radical scavenging activity and α-glucosidase inhibitory activity in peel, core and pulp of five different pear cultivars. Oligomeric polyphenols were the main polyphenols in core, which exhibited greater polyphenols, DPPH radical scavenging activity, and α-glucosidase inhibitory activity, compared to peel and pulp. For the peel, Japanese pears including Yasato, 20-Seki and Shinko pear contained relatively more polyphenol content and α-glucosidase inhibitory activity, compared to European pears including Starkrimson and Purekosu pear. Monomeric polyphenols were the main polyphenols in the peel of European pears, in contrast, oligomeric polyphenols were the main polyphenols in those of Japanese pears. The peel of Yasato pear had high ratios of non-monomeric polyphenols, and showed highest DPPH radical scavenging activity and α-glucosidase inhibitory activity amongst five pear cultivars. Thus DPPH radical scavenging activity and α-glucosidase inhibitory activity may be related with non-monomeric polyphenols in pears. Moreover, as comparing with peel, pulp had lower polyphenol content, DPPH radical scavenging activity and α-glucosidase inhibitory activity. All of the observations suggested that peel and core of pear contained abundant polyphenols and possess potential the values of reusing.

Keywords:
pear peel core polyphenol DPPH radical scavenging activity α-glucosidase

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