Comparing green extraction methods for the recovery of protein-rich fraction from peach seeds (Prunus persica)

Abstract

Peach processing generates significant volume of coproducts, such as the underutilized peach seeds, which are rich in fatty acids and protein. The recovery of protein-rich fractions from peach seeds is highly relevant because of the increasing demand for alternative non-animal protein sources. This study aimed to investigate different extraction techniques for protein recovery from the underestimated peach seeds, and evaluate the functionalities of the protein fraction. The peach seeds were defatted using the supercritical fluid extraction (SFE-CO2), with oily recovery up to 29.53% ± 0.45. Then, the protein fraction was recovered using the following methods: heat-stirred extraction (HSE) as a conventional method, and, as alternative procedures, microwave-assisted extraction (MAE), pressure liquid extraction (PLE), and ultrasound-assisted extraction (UAE) using NaOH solution as solvent. The PLE provided the highest protein content (95.10 % ± 0.98), followed by the HSE technique (55.09% ± 0.35). Furthermore, the PLE showed the best performance in techno-functional properties of the protein fraction: emulsion activity, foaming, turbidity, free sulfhydryl content, hydrophobicity, and color, compared to the classical HSE technique. Therefore, it is suggested that PLE (10 min) method recovered an isolated protein with better functional properties, providing promising result for protein purification. Therefore, PLE can be considered an alternative method to add value to underestimated peach seeds, conferring the upcycling concept.