Production, bioactivities and bioavailability of bioactive peptides derived from walnut origin by-products: a review

Walnut-origin by-products obtained from walnut oil extraction industry are high in proteins with various physiological functions and pharmacological properties and an extensive potential for usage in producing bioactive peptides. This review presents the current research status of bioactive peptides derived from walnut by-products, including preparation, separation, purification, identification, bioactivities, and bioavailability. A plethora of walnut peptides with multiple biological activities, including antioxidative, antihypertensive, neuroprotective, antidiabetic, anticancer, and antihyperuricemia activities, were obtained from walnut-origin by-products by enzymatic hydrolysis, fermentation, and synthesis. Different bioactive peptides show various structural characteristics and amino acid composition due to their diverse mechanism of action. Furthermore, walnut protein and its hydrolysate present a high bioavailability in human gastrointestinal digestive system. Improving the bioavailability of walnut peptides is needful in the development of walnut industry. However, future research still needs to exploit energy conservation, high efficiency, environmentally friendly and low-cost production method of walnut bioactive peptide. The molecular mechanisms of different bioactive walnut peptides still need to be explored at the cell and gene levels. Additionally, the digestion, absorption, and metabolism processes of walnut peptides are also the focus of future research.

Automated summary

This review provides an overview of the current research status of bioactive peptides derived from walnut by-products. The review covers the preparation, separation, purification, identification, bioactivities, and bioavailability of these peptides. It highlights the various biological activities exhibited by walnut peptides, including antioxidative, antihypertensive, neuroprotective, antidiabetic, anticancer, and antihyperuricemia activities. The review also emphasizes the need for further research in improving the bioavailability of walnut peptides and exploring their molecular mechanisms. Digestion, absorption, and metabolism processes of walnut peptides are also identified as important areas for future research.