Effects of simulated digestion on the phenolic composition and antioxidant activity of different cultivars of lychee pericarp

Qingzhu Zeng,Ruifen Zhang,Mingrui Dai,Xiong Xiong,Xuejiao Cao,Mingwei Zhang,Dongxiao Su,Lihong Dong,Yang Yuan,Zhuohui Xu,Shan He

doi:10.1186/s13065-019-0544-4

Qingzhu Zeng, Ruifen Zhang + Show 9 more

Open Access

https://doi.org/10.1186/s13065-019-0544-4

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Abstract

BackgroundLychee pericarp is rich in phenolic and has good antioxidant activity. The effects of simulated gastric (SGF) and intestinal fluid (SIF) digestion on the contents, composition, and antioxidant activities of the phenolic substances in the pericarp of different lychee cultivars (cv Jizui, Lizhiwang, Guiwei, Yuhe, Nuomici and Guihong) were investigated.ResultsCompared with distilled water (DW) treatment, the total phenolic content (TPC) and total flavonoid content (TFC) in the pericarp of different lychee cultivars decreased after SGF digestion; especially, the TFC in “Lizhiwang” decreased by 41.5%. The TPC and TFC of lychee pericarp also decreased after SIF digestion. However, the TPC in “Jizui”, “Guiwei” and “Yuhe” increased. The SGF and SIF also had different effects on the FRAP and ABTS antioxidant activities of different lychee cultivars. The SGF digestion decreased the ABTS antioxidant capacity of lychee pericarp but enhanced the FRAP value of some lychee cultivars. However, the SIF digestion decreased the FRAP antioxidant activity of different lychee cultivar pericarps but enhanced the ABTS antioxidant capacity of lychee. The HPLC results showed that lychee pericarp had relatively high contents of procyanidin B2 and procyanidin A2. After SIF digestion, caffeic acid and isoquercitrin could not be detected in any of the lychee varieties. However, quercetin-3-rutinose-7-rhamnoside and isoquercitrin were increased after SGF digestion.ConclusionsLychee pericarp could be used as an inexpensive functional food ingredient.

Highlights

Lychee pericarp is rich in phenolic and has good antioxidant activity
The total phenolic content (TPC) in the pericarp of different lychee cultivars was significantly different after distilled water extraction and Simulated gastric fluid digestion (SGF) treatment (p < 0.05)
The results showed that the content of phenolic substances in lotus leaves at different growth stages increased after simulated intestinal fluid (SIF) digestion, which was similar to the results of this study

Summary

Introduction

Lychee pericarp is rich in phenolic and has good antioxidant activity. Lychee is a kind of fruit which is beneficial to human health [1]. It has brightly colored skin, translucent and congealed flesh, and a sweet and delicious taste, so it is very popular all over the world [2, 3]. Lychee is widely cultivated in tropical and subtropical countries [4], including China, India, Thailand, Vietnam and America. Among these countries, China has the highest yield and largest planting area. The TPC of lychee pericarp was about 51–102 mg/g [2], which was higher than lotus leaves [6] and grape skins [7]

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