Preparation and Bioactivity of Walnut Peptides: A Review

Walnut is an important woody oil crop. Walnut meal left after oil extraction is rich in high-quality protein, but it is underutilized, causing a waste of resources. Bioactive peptides derived from walnut meal protein have the potential for food development and are a promising ingredient in functional foods owing to their diverse bioactivities such as antioxidant, cardiovascular protective and memory improving activities. The effective utilization of walnut meal protein, for example by developing bioactive peptides is of great significance to realize the comprehensive utilization of walnut meal and to improve the added value of products. This review summarizes previous studies on the preparation, purification, identification and biological activity of walnut peptides in order to provide a theoretical basis for the high-value utilization of walnut meal protein resources and in-depth studies of walnut protein peptides.