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This study examined the effects of two fat-to-lean ratios (7:3 and 6:4) and five cooking times (30 min, 60 min, 90 min, 120 min and 150 min) on water migration in and the nutritional quality and fatty acid composition of traditional Chinese pork meatballs. Accordingly, this work has established a quality control reference for the industrial-scale research and development of pork meatball production. Low-field nuclear magnetic resonance was used to determine the distribution and migration of water in pork meatballs during the cooking process, and gas chromatography–mass spectrometry was used to determine the fatty acid composition of pork meatballs. The results show that the water in pork meatballs migrated and thus became more strongly bound as the cooking time increased. The relaxation time of water in pork meatballs with a fat-to-lean ratio of 7:3 was significantly higher than that of water in pork meatballs with a fat-to-lean ratio of 6:4 (P <.05). The length of cooking time did not have a significant effect on the protein or fat content of pork meatballs (P >.05). When the pork meatballs were cooked for 150 min, the calorie value of pork meatballs with a fat-to-lean ratio of 7:3 was significantly greater than that of pork meatballs with a fat-to-lean ratio of 6:4. The hardness and tenderness of pork meatballs with a fat-to-lean ratio of 7:3 were significantly lower than those of pork meatball with a fat-to-lean ratio of 6:4 (P <.05), but the elasticity and chewiness of the former were greater than that of the latter. During cooking, the improvement in the thiobarbituric acid reactive substances (fat oxidation) value of pork meatballs with a fat-to-lean ratio of 6:4 was greater than that of pork meatballs with a fat-to-lean ratio of 7:3. The main fatty acids in both types of pork meatballs were oleic acid (C18:1 n9c), linoleic acid (C18: 2), palmitic acid (C16:0) and stearic acid (C18:0), with oleic acid (C18:1n9c) being predominant. These results show that in terms of taste and textural requirements, and unsaturated fatty acid content, pork meatballs with a fat-to-lean ratio of 7:3 and a cooking time of 150 min can best meet the texture preferences and nutritional needs of consumers. [ABSTRACT FROM AUTHOR]

The effect of freeze-thaw cycling on the quality of pre-fermented red bean steamed bun (RBSB) dough and the cooked product were explored. For frozen dough samples, the changes in water distribution, frozen water content, starch crystallinity, layered structure, and protein secondary structure of the dough during freeze-thaw cycling were analyzed. The textures, colors, and relative amino acids contents of RBSBs, which were steamed from frozen dough, were analyzed. The results showed that the transverse relaxation time of weakly bound water,T22,increased as the number of freeze–thaw cycles increased, and the freezable water content reached its highest value (14.68%) after 1 cycle. The relative crystallinity of starch was increased by 13.6% compared with the control after 4 freeze-thaw cycles. The lamellar structure of starch increased by 4.33% after more than 5 freezing cycles. Freeze-thaw treatments caused significant and irregular changes in the secondary structure of the frozen dough. Freeze-thaw cycling accelerated an increase in the hardness of RBSB products. The brightness (L*) of RBSBs decreased significantly with increases in the number of freeze-thaw cycles, and these cycles also affected the amino acid contents of RBSBs. [ABSTRACT FROM AUTHOR]