Walnut (Juglans regia L.) contains approximately 20–25 % protein with abundant essential amino acids. The enzymatic hydrolysate of Persian walnut (Chandler) seed proteins was prepared by incubation with three different proteases, including pancreatic chymotrypsin and trypsin, and a microbial enzyme proteinase K. The hydrolysates were found to possess excellent antioxidant capacities. The peptide fractions scavenged the 2, 2′-anizo-bis-(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) free radicals and inhibited the activity of reactive oxygen species. Walnut protein hydrolysates were also tested, for the first time, against the viability of human breast (MDA-MB231) and colon (HT-29) cancer cell lines. MTT, [3–(4, 5dimethylthiazolyl)-2,5-diphenyl-tetrazolium bromide], assay was used to assess in vitro cancer cell viability upon treatment with the peptide fractions. The peptide fractions showed cell growth inhibition of 63 ± 1.73 % for breast cancer and 51 ± 1.45 % for colon cancer cells. Thus, a direct correlation between antioxidant and anticancer activities of walnut peptide fractions exists and supports their potential therapeutic benefit.

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The aim of this study was to evaluate the effects of enzymatic hydrolysis of camel whole casein on their antioxidant and angiotensin-converting enzyme (ACE)-inhibitory properties. Whole camel casein was hydrolyzed by proteinase K (PK), and the hydrolysates were fractionized by ultrafiltration membranes into three fractions. Semi-preparative reversed-phase high-performance liquid chromatography (RP-HPLC) was used to differentiate the mixture of peptides in the 3 kDa permeate fractions. A fraction (F4) with potentials of ACE-inhibitory activity (IC50 = 73 μg.mL −1 ) and radical scavenging activity (IC50 = 6.8 μg.mL −1 ) was selected for further purification and fractionation. The fraction F4C obtained from a second step purification of F4 showed strong ACE-inhibitory activity (IC 50 = 36 μg.mL −1 ) as well as radical scavenging activity (IC 50 = 3.3 μg.mL −1 ). The results of this study suggest that whole camel casein can be considered as a promising source for the production of peptides with potential of ACE-inhibitory and antioxidant activities.

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