A simple and convenient method for the preparation of antioxidant peptides from walnut (Juglans regia L.) protein hydrolysates

Ming-Chuan Liu,Chia-Hui Huang,Yun Lin,Da Hong,Min Liu,Sheng-Jie Yang,Jin-Ping Yang,Chao-Jih Wang

doi:10.1186/s13065-016-0184-x

Ming-Chuan Liu, Chia-Hui Huang + Show 6 more

Open Access

https://doi.org/10.1186/s13065-016-0184-x

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Journal: Chemistry Central Journal	Publication Date: Jun 21, 2016
Citations: 38	License type: CC BY 4.0

Affiliation: Shenyang Pharmaceutical University

Abstract

BackgroundWalnut (Juglans regia L.), that belongs to the Juglandaceae family, is one of the nuts commonly found in Chinese diets. Researchers had obtained peptides from walnut protein hydrolysates, and these peptides exhibited the high antioxidant activities. The objective of this study was to develop a simple and convenient method for a facile and reproducible preparation of antioxidant peptides from walnut protein hydrolysates.ResultsWalnut proteins were extracted from walnut kernels using continuous countercurrent extraction process, and were separately hydrolyzed with six types of proteases (neutrase, papain, bromelain, alcalase, pepsin, and pancreatin). Then, hydrolysates were purified by ultrafiltration. The yields and purity of the peptides prepared using neutrase and papain were 16 and 81 % at least, respectively, higher than others, and had low molecular weight, 99 % of which were less than 1500 Da. Furthermore, the bioassay indicated that the two peptides exhibited the high antioxidant activities in the DPPH (IC50 values: 59.40 and 31.02 µg/mL, respectively), ABTS (IC50 values: 80.36 and 62.22 µg/mL, respectively), and superoxide radical scavenging assay (IC50 values: 107.47 and 80.00 µg/mL, respectively).ConclusionsThe method combines the advantages of generality, rapidity, simplicity, and is useful for the mass production of walnut peptides.Graphical Preparation of antioxidant peptides from walnut (Juglans regia L.) protein hydrolysates

Highlights

Walnut (Juglans regia L.), that belongs to the Juglandaceae family, is one of the nuts commonly found in Chinese diets [22, 23]
The two types of proteases could hydrolyze walnut protein isolates (WPIs) efficiently, which should be selected for further use to prepare walnut peptides (WPs)
The peptides were further purified from protein hydrolysates through using an ultrafiltration membrane with molecular weight cut-off (MWCO) of 2 kDa

Summary

Introduction

Walnut (Juglans regia L.), that belongs to the Juglandaceae family, is one of the nuts commonly found in Chinese diets. Researchers had obtained peptides from walnut protein hydrolysates, and these peptides exhibited the high antioxidant activities. Reactive oxygen species are atoms, molecules, or ions with unpaired electrons or open-shell configurations, such as hydroxyl radical (·OH), superoxide anion radical (O2·−) [6, 7] Their formation has been associated with many human diseases, such as heart disease [8], stroke [9], Liu et al Chemistry Central Journal (2016) 10:39 antioxidant activity [17,18,19]. Researchers had purified peptides from walnut protein hydrolysates using gel chromatography, and these peptides exhibited the highest antioxidant activities and had angiotensin I-converting enzyme (ACE) inhibitor activity [40, 41]. Every method had its own advantages and disadvantages, so all of these led to our interesting in investigating a large-scale production suitable for walnut peptides

Objectives

Results

Conclusion