Xu Chen,Ling Li,Fujia Yang,Jinhong Wu,Shaoyun Wang
Cold stage adversely affects cell proliferation and cell viability of probiotics such as Streptococcus thermophilus in food industry, new type of cryoprotectants continues to be needed. Gelatin-based antifreeze peptide becomes a popular topic because of its cryoprotective effects on cold-stressed probiotics. In this study the effects of tilapia scales antifreeze peptides (TSAPP) on cell viability and oxidant stress of S. thermophilus during cold stage were investigated. The results showed that the percentage of viable cells was increased 10.85 folds compared with control groups. Addition of TSAPP activated the activities of ATPases, relieved the hyperpolarization of cell membrane potential and regulated the intracellular Ca 2+ concentration. Furthermore, TSAPP significantly inhibited reactive oxygen species level and malonaldehyde content in cells. Under cryopreservation with TSAPP, cells of S. thermophilus maintained higher activities of antioxidant enzymes including catalase , peroxidase and total antioxidant capacity . These findings indicate that TSAPP likely offered its cellular protection by maintaining membrane integrity and alleviation of oxidative stress .
RiBang Wu,CuiLing Wu,Dan Liu,XingHao Yang,JiaFeng Huang,Jiang Zhang,Binqiang Liao,HaiLun He
Extracted salmon skin collagen was hydrolysed with the free or immobilized extracellular protease of Vibrio sp. SQS2-3. The hydrolysate exhibited anti-freezing activity (>3 kDa) and antioxidant activity (<3000 Da) after ultrafiltration. The antioxidant peptide was further purified by size-exclusion chromatography and found to scavenge DPPH (73.29 ± 1.03%), OH (72.73 ± 3.34%,), and intracellular ROS in HUVECs; protect DNA against oxidation-induced damage; and have an ORAC of 2.78 ± 0.28 mmol TE/g. The antioxidant peptide fraction was identified using mass spectrometry, and nineteen salmon collagen-sourced peptides were obtained. Of these, the peptide Pro-Met-Arg-Gly-Gly-Gly-Gly-Tyr-His-Tyr is a novel sequence and was the major component; this peptide was shown to have antioxidant activity via the ORAC assay (2.51 ± 0.14 mmol TE/g). These results suggested that the protease from Vibrio sp. SQS2-3 is suitable for preparation of anti-freezing peptides and antioxidant peptides in a single step and represents a comprehensive use of fish skin collagen.
危险品化学品经营许可证（带存储）