Gelling properties and structure modification of tilapia skin gelatin by the addition of γ‐polyglutamic acid at different pH levels

Abstract

Fish gelatin (FG) has similar functional properties to mammalian gelatin and is a potential mammalian gelatin substitute. However, its poor gelling properties limit its application in many fields. Early on, cpolyglutamic acid (c-PGA) was found to be effective in improving the gel properties of FG. Therefore, the gelling properties and structure of c-PGA to FG under different pH levels were further studied in this article. When the pH of the system is 3, c-PGA is positively charged; when the pH of the system is ≥5, c-PGA is negatively charged, while FG is positively charged, so the change of the pH of the system affects the electrostatic binding ability of FG and c-PGA. A c-PGA concentration of 0.04% (w/v) and FG at pH 5 yielded the best gelling properties. Moreover, pH affected the formation of helices during gelatin gelation, and it had a significant effect on the nanostructure of FG. The relationship between structure and physicochemical properties was proposed as a schematic model.

Improving gelling properties of fish gelatin by γ‐polyglutamic acid with four different molecular weights

“…It has been suggested that due to the fact excessive molecular weight γ‐PGA (Mw > 1000 kDa) has excessive viscosity, it is used as a thickening agent in food (Wang et al ., 2022). Because γ‐PGA enhanced the viscosity within the FG‐γ‐PGA system and strengthened the gel network structure of FG (Hu et al ., 2021b). Therefore, the larger molecular weight of γ‐PGA added to FG, the greater gel strength of FG.…”

“…It indicated FG and γ‐PGA were bonded through non‐covalent bonds. This is in line with previous findings by other researchers (Hu et al ., 2021b). Because of the large molecular weight of γ‐PGA polymer, little electrophoretic migration occurred within the electrophoretic band, thus FG‐γ‐PGA only showed the electrophoretic band of FG in electrophoresis (Yamaguchi et al ., 1996).…”

Development of fish gelatin-chitooligosaccharide conjugates through the Maillard reaction for the encapsulation of curcumin

“…Fish gelatin (FG) is mostly obtained from fish products waste such as fish skin, bones, scales, and gills ( Hu et al, 2021 ). It is considered to be the ideal and most potential substitute for mammalian gelatin ( Lv et al, 2019 ).…”