Antioxidant Activity and Stability Study of Peptides from Enzymatically Hydrolyzed Male Silkmoth

Abstract

The antioxidant activity and stability of peptides from male silkmoth hydrolysates (MSH) was studied as antioxidant ingredients in potential food applications. MSH were isolated into five fractions: MSH‐I (MW > 30 kDa), MSH‐II (10–30 kDa), MSH‐III (5–10 kDa), MSH‐IV (3–5 kDa), and MSH‐V (<3 kDa) by ultrafiltration. The antioxidant activity, molecular weight distribution and amino acid contents of each fraction were evaluated. The effects of NaCl, temperature, pH, light intensity and simulated gastrointestinal digestion were assessed to determine the stability of peptides. The antioxidant capacity of MSH‐I as a major antioxidant component was 1,950 µmol/g in ORAC assay and 275 µmol/g in DPPH scavenging method. MSH showed good stability when salinity was less than 4%, temperature below 60C, and pH between 4 and 8. The antioxidant activity could retain about 80% after simulated gastrointestinal digestion. In conclusion, the MSH is a promising resource for stable antioxidant peptides applied in functional food processing and storage. Practical Applications In sericulture, the total cocoon yield has been 738,100 tons, the silk yield has been 93,000 tons, even about 60,000 tons of tussah moth cocoons produced in China in 2005. However, accompanied by the ascension of the silk consumpution, the sonsiderable amount of by‐product and sericulture waste presented rising trend yearly. While, moth as insect having allergy protein, which use has been limited, but it has an excellent protein and active peptides and other ingredients (to improve immunity and sexual function), comprehensive utilization of silkmoth turns into meaningful topics. Using enzyme technology or fermentation technology (Protein degradation) to develop its protein resource utilization in silkmoth becomes the effective tools to solve this problem. The present experiments studied antioxidant activity by ultrafiltration technology and stability study of peptides from enzymatically hydrolyzed male silkmoth.

Effect of processing conditions and simulated gastrointestinal digestion on the activity of angiotensin I-converting enzyme (ACE) inhibitory peptide derived from duck meat hydrolysate

“…As shown in Figure 2(d), there was no significant change in the activity of ACE-inhibitory peptide under different contents of NaCl (P > 0.05). It was reported that 6% NaCl could decrease the bioactivity of peptide through the reduction of solubility (Liu, Wan, Liu, Zou, & Liao, 2017b). The result in our study may be attributed to the good solubility of ACE-inhibitory peptide in NaCl solution.…”

Stability of antioxidant peptides from duck meat after post‐mortem ageing

“…The DPPH radical scavenging and FRAP of the samples significantly decreased ( P < 0.05) with the increase in pH value above 7. Similar results were also reported for antioxidant peptides extracted from Jinhua ham (Zhu et al ., ) and peptides from enzymatically hydrolysed male silk moth (Liu et al ., ).…”

“…() found that the Fe 2+ ‐chelating ability of antioxidant peptides extracted from Jinhua ham showed no significant change under various NaCl contents treatments. However, the antioxidant activity of male silk moth hydrolysates decreased with the increased concentration of NaCl, which may be caused by a salting phenomenon and reduced solubility of peptides resulted from the increased NaCl gradient (Liu et al ., ).…”

Structural and functional properties of food protein-derived antioxidant peptides

“…Given the growing interest in using underutilized foods as inexpensive sources for the production of bioactive peptides, there has been an upsurge in the number of studies examining the antioxidant properties of peptides generated from hitherto conventionally inedible or non‐conventional foods in recent years. These include hydrolyzates and peptides from the red alga Palmaria palmata (Harnedy et al, ), processed fish wash water (Zhou et al, ), chicken blood cells (Zheng, Si, Ahmad, Li, & Zhang, ), squid pen chitosan (Shavandi et al, ), abalone viscera (Je, Park, Hwang, & Ahn, ), pearl oysters (Ma, Wu, & Li, ), rice bran (Phongthai et al, ), mulberry leaf (Sun et al, ), and silkworm (Liu, Wan, Liu, Zou, & Liao, ). Others include microorganisms and single cell organisms (Alzahrani, Perera, & Hemar, ), blood clam (Chi, Hu, Wang, Li, & Ding, ), and echinoderm byproducts (Mamelona, Saint‐Louis, & Pelletier, ).…”