Lin Gu,Yuanzhang Jiang,Larry M.C. Chow,Zhen Liu,Wei Gao,Yanting Han,Cong Wang,Jinlian Hu
Spiders can produce different types of silks with different functions by tuning the hierarchical structure of spidroin. Inspired by the secondary structure of spider silk, a series of peptide-polyurethane/urea (PUU) hybrids with various peptide contents were synthesized in this work. By effective control of polymerization degree, simultaneous presence of α -helixes and β -sheets in the polymer was realized. The modulus of films increased with peptide loading and reached more than 200 MPa at 71.1% peptide content. Notably, the PUU hybrid with 41.5% peptide content (P-41.5) showed the highest tensile strength (6.6 MPa) and strain (1238%). At the same time, this film (P-41.5) exhibited shape memory effect at 37 °C, as well as excellent shape recovery ratio during successive cycles at 100% strain. Furthermore, Ag nanowires/P-41.5 hybrid film exhibited superb electric resistance stability under bending and stretching conditions, making it a promising material for strain sensors.
To investigate the umami mechanisms and characteristics of soy sauce flavor peptides, four fractions from natural brewed soy sauce were separated using ultrafiltration and Sephadex G-15 gel filtration chromatography. Sensory and ligand-receptor interaction tests showed that the umami strengths of the fractions were related as follows: U1 > U2, G3 > G2, and G3 > U1. Peptide identification revealed that the < 550-Da peptides might be the major contributors to the umami taste of U1 and G3. The higher umami strength of G3 might be attributable to its higher content of umami peptides. G3′s concentration-relative umami intensity curve was plotted using a two-alternative forced choice test. It was also revealed that less sourness, higher saltiness and cool (4 ℃) and hot (50 ℃) serving conditions were conductive to the umami perception of G3. The results could provide a reference for the application of soy-sauce flavor peptides in food.
危险品化学品经营许可证（带存储）