Low-field nuclear magnetic resonance analysis of the effects of heating temperature and time on braised beef

Summary We investigated the characteristics of water mobility and distribution in Chinese braised beef after treatment at different temperatures for different times using low-field nuclear magnetic resonance (LF-NMR). The beef was heated at 45, 55, 65, 75, 85 or 95 °C for 30, 60, 90 and 120 min. Results showed that T2 changed significantly with heating temperature. T21 and A21 decreased significantly with increasing temperature below 65 °C, with a steady phase from 75 to 95 °C, which agreed with cooking loss. Inversely, T22 had no changes below 65 °C and changed apparently from 75 to 95 °C. The change in T21 below 65 °C may be related to proteins denaturation and shrinkage and, above 65 °C, T22 possibly induced by the dissolution of connective tissue. The characteristics of braised beef at 65 °C were different from those at other temperatures in T2 distributions. The findings could provide a theoretical basis for the processing of Chinese braised beef.