Evaluation of Physicochemical and Antioxidant Properties of Peanut Protein Hydrolysate

Lin Tang,Li Na Yu,Hui Cui Zhang,Qing Li Yang,Feng Zhu,Chu Shu Zhang,Shao Fang Liu,Jie Sun,Jie Bi,Vladimir N Uversky

doi:10.1371/journal.pone.0037863

Abstract

Peanut protein and its hydrolysate were compared with a view to their use as food additives. The effects of pH, temperature and protein concentration on some of their key physicochemical properties were investigated. Compared with peanut protein, peanut peptides exhibited a significantly higher solubility and significantly lower turbidity at pH values 2–12 and temperature between 30 and 80°C. Peanut peptide showed better emulsifying capacity, foam capacity and foam stability, but had lower water holding and fat adsorption capacities over a wide range of protein concentrations (2–5 g/100 ml) than peanut protein isolate. In addition, peanut peptide exhibited in vitro antioxidant properties measured in terms of reducing power, scavenging of hydroxyl radical, and scavenging of DPPH radical. These results suggest that peanut peptide appeared to have better functional and antioxidant properties and hence has a good potential as a food additive.

Highlights

Peanut is the world’s fourth most important source of edible vegetable oil and the third most important source of vegetable protein feed meal [1]
Peanut peptide and protein solubility Protein solubility (PS) of a given protein is directly related to pH of the solution as it depends on the pI of the protein
The PS of peanut peptide and peanut protein isolate were determined across a range of pH values in phosphate buffer (Fig. 1)

Summary

Introduction

Peanut is the world’s fourth most important source of edible vegetable oil and the third most important source of vegetable protein feed meal [1]. In China, peanuts have been grown as an oil seed crop for export and for production of the edible oil, while the protein residue in the form of oil cake is used as animal feed [2,3]. One of the notable features of peanut protein is its high nutritional value; but its functional properties, digestibility and bioactivity are relatively low [4]. Its hydrolysate which is peanut peptide could have better physicochemical properties such as the solubility, emulsifying capacity, foam capacity, etc. Certain peptide sequences that are correlated with potent antioxidative and radical scavenging functions have been identified by sequence comparison of various proteins and are present in peanut protein [5]

Methods

Results

Conclusion