In vivo assessment of immunomodulatory activity of hydrolysed peptides from Corylus heterophylla Fisch

Hazelnut dregs are by-products of hazelnut oil expression, which have not been fully exploited. This research aims to assess the immunomodulatory function of hazelnut hydrolysed peptides (HHPs).HHPs with a hydrolysis degree of 38.08% were divided into three fractions by ultra-filtration: the high molecular weight peptide (>10 kDa), medium molecular weight peptide (3 kDa to 10 kDa), and low molecular weight peptide (<3 kDa). Mice were fed daily with HHPs of different molecular weights at doses of 200, 400, and 800 mg kg(-1) body weight. On the 10th, 20th and 30th day of feeding, representative immune indexes were measured. Results showed that HHPs can regulate the immune system of mice, which is affected by the molecular weight of HHP and the feeding time. Generally, short-term feeding (10 d to 20 d) with HHPs of different molecular weights can improve most immune indexes (organ index, spleen lymphocyte proliferation, macrophage activity, secretory immunoglobulin A content, and number of CD4(+) and CD8(+) T cells), whereas during long-term feeding (30 d), low molecular weight HHP can better sustain immune regulation.HHPs exhibit potential immunomodulatory properties, which has promising implications for the development of new functional foods. © 2015 Society of Chemical Industry.