Quality improvement of minced pork during glassy-state frozen storage with high glass transition temperature induced by tara gum.

Abstract

Minced pork stored at -35 °C, -35 °C + 0.9% tara gum (TG, glassy state), and - 46 °C (glassy state) was used to evaluate the effect of TG on quality during glassy-state frozen storage (0-180 days) and its underlying mechanism. Adding 0.9% TG increased the glass transition temperature (Tg') of minced pork from -45.4 °C to -34.9 °C, thereby achieving a glassy state at -35 °C. Results showed that compared with the -35 °C group, the -35 °C + 0.9% TG group significantly alleviated quality deterioration (P < 0.05), and its preservation quality was comparable to that of the -46 °C group. Specifically, the -35 °C + 0.9% TG and - 46 °C group showed no significant differences (P > 0.05) in color, thawing loss, centrifugal loss, Ca2+-ATPase activity, free amino content, or ice crystal size. However, the TG treatment group more effectively inhibited water migration and the unfolding of myofibrillar protein (MP). Compared with the -46 °C group, the -35 °C + 0.9% TG group reduced the fluorescence peak wavelength, T21, and T22 relaxation times by 5.17%, 3.88%, and 5.67%, respectively, while increasing α-helix content by 2.58%. These findings provide theoretical support for reducing energy consumption in deep-freeze storage and expanding the application of natural polysaccharides in glassy-state frozen storage.