Bioactive phytochemicals and antioxidant activity in fresh and dried lychee fractions1

Estela De Rezende Queiroz,Vinicius De Oliveira Ramos,Kelly Da Silva Oliveira,Celeste Maria Patto De Abreu,Rodrigo Martins Fráguas

doi:10.1590/s1806-66902015000100019

Abstract

Fruit of the lychee cv. Bengal are approximately 50% peel and seeds, which are discarded. These by-products have antioxidant compounds which are capable of blocking the harmful effects of free radicals in the body. Bioactive compounds (ascorbic acid, beta-carotene, lycopene and phenols) and antioxidant activity were evaluated in different extracts, both fresh and dried at 45 °C, of the skin, pulp and seeds of the lychee, which were subjected to principal component analysis to clarify which of the compounds are responsible for this activity. Principal component analysis explained 82.90% of the variance of the antioxidant profile of the lychee. The peel displayed higher levels of phenols, ascorbic acid, beta-carotene and antioxidant activity, while the seeds stood out due to their levels of lycopene. With drying, there was a decrease in the levels of ascorbic acid and beta-carotene and in antioxidant activity, with an increase in the levels of phenols and lycopene. The antioxidant activity found in the peel and seeds of the lychee is high, and is mainly due to ascorbic acid and beta-carotene, as demonstrated by principal component analysis, allowing the use of these fractions as sources of natural antioxidants.

Highlights

The lychee (Litchi chinensis Sonn.), a species of the Sapindaceae family suited to subtropical-climates, is of Chinese origin and is perfectly adapted to Brazilian climatic conditions
The peel and seed are rich in antioxidants such as ascorbic acid, phenolic compounds including gallic acid, flavonoids, and anthocyanins
Between the fractions in natura, the seed showed the lowest content for phenolic compounds (11.45 mg 100 g-1 dry matter (DM)), with no significant differences being found (p0.05) (Table 1), especially for the peel

Summary

Introduction

The lychee (Litchi chinensis Sonn.), a species of the Sapindaceae family suited to subtropical-climates, is of Chinese origin and is perfectly adapted to Brazilian climatic conditions. Bengal are about 50% peel and seed, which are discarded by both industry and consumers (KUMAR; KUMAR; SHARMA, 2012). Lychee production in the country has still not been determined (SMARSI et al, 2011), but is focused mainly in the southeast. In Brazil, industries that benefit from the lychee use the pulp in the preparation of ices and jams. Recent work has been carried out, aiming to evaluate the nutritional potential of the by-products of lychee fruit, with initial results indicating that the peel and seed have high energy and nutritional potential (QUEIROZ; ABREU; OLIVEIRA, 2012). Pharmacological studies indicate that the by-products of the lychee have various effects including anti-inflammatory, anti-hyperlipidemic, anti-hyperglycemic, hepatic and cardioprotective, as well as having high antioxidant activity (BHOOPAT et al, 2011; JIANG et al, 2013; XU et al, 2011)

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Conclusion