Original scientific paper

Antioxidant and Prebiotic Activity of Enzymatically Hydrolyzed Lychee Fruit Pulp

Naraporn Fasawang ; Program in Biotechnology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
Pranee Anprung ; Department of Food Technology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand

Abstract

The optimal extraction of bioactive compounds from lychee fruits using commercial Pectinex® Ultra SP-L pectinase hydrolysis of the fruit pulp homogenate was evaluated. The lychee fruit pulp was treated with the pectinase at volume per mass ratios between 0.5
and 2.5 % for 0.5–5 h. The degree of hydrolysis (DH), monitored as the level of released reducing sugar, increased with the increase of enzyme volume per mass ratio and time up to 2 % and 4 h, respectively, to give a maximum DH of 19 %. The antioxidant activity in lychee pulp hydrolysates increased with increasing DH, with the highest DH of 19 % displaying an EC50 of 0.25 μg of fresh mass (FM) per μg of diphenyl-(2,4,6-trinitrophenyl)- iminoazanium and 53.17 μM of Trolox equivalents per g of FM. The lychee hydrolysate with the DH of 19 % had the highest level of total phenolic acids (165.8 mg of gallic acid equivalents per 100 g of FM) and flavonoids (70.8 mg of catechin equivalents per 100 g of FM), and the highest prebiotic activity score of 1.68 and 0.82 of Bifidobacterium lactis Bb12
and Lactobacillus acidophilus La5, respectively. In accordance with the level of phenolic acids and flavonoids, the lychee hydrolysate with the DH of 19 % revealed a reasonably good level (72–77 %) of lipid peroxidation inhibition in soya bean, lard and olive oil. The lychee
hydrolysate with the DH of 19 % increased the number of detected volatile compounds to 37, with 11 new compounds that were not found in the lychee hydrolysate with the DH of 0 %. Moreover, the particle size and insoluble fibre level were reduced with a concomitant
increase in the soluble fibre level.

Keywords

pectinase; lychee pulp; antioxidation; prebiotics

Hrčak ID:

126175

URI

https://hrcak.srce.hr/126175

Publication date:

15.9.2014.

Article data in other languages: croatian

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