| Frozen food, for its characteristics of convenience, health and superior quality and beingin line with nowadays fast-paced lifestyle, is greatly popular with the majority of consumersand possess good market prospects. Dumplings, as one of our country’s staple food, aredelicious, nutritious and become the favorite to the public. Quick-frozen dumplings,belonging to the set of frozen prepared foods, not only have the characteristics of convenienceand health for quick-frozen food, but they also retain the flavor and quality of fresh dumplingsto maximum limits. As one main category of the quick-frozen food industry in our country,quality changes and control of quick-frozen dumplings in the process of production,processing, transportation and sales have a greatly important significance for the developmentof native quick-frozen food industry. Currently studies on quick-frozen dumplings mainlyfocused on quality changes and control of dumpling skin, while there’re relatively fewresearches in fillings. Above these, this paper selected minced pork of quick-frozen dumplingas the research subject, took the means of frozen storage and simulated repeated freezing andthawing caused by the rupture of cold strand in the actual process of circulation. Thawinglosses, cooking loss, texture and thiobarbituric acid value (TBARS) were measured todetermine the quality changes of the ground meat. On account of the phenomena of seriousjuice loss and oxidation deterioration, antioxidants butyl hydroxy anisd (BHA) and butylatedhydroxytoluene (BHT), emulsifier monostearin (GMS) and sucrose esters (SE) were added tocontrol quality deterioration.1．In the three-month frozen storage experiment of minced pork in quick-frozen dumplings,with the extension of frozen time, the water-holding capacity of ground meat decreased, asdemonstrated by thawing loss and cooking loss increased; ground meat tasted worse and theirhardness, elasticity, cohesiveness and chewiness dropped overall; fat oxidation aggravated.After three months of frozen storage, TBARS values of the filling reached2.03mg/kg（P<0.05） and has generated obvious off-flavors.2．In the repeated freezing and thawing experiment of ground meat, the results showed thatrepeated freezing and thawing greatly accelerated deterioration of the meat. After repeatedfreezing and thawing for eight times, water-holding capacity of the meat declined and theirtexture and degree of fat oxidation were far greater than those storaged under-18℃for thesame time without freezing and thawing. Whilst thawing loss, cooking losses and TBARSvalues of ground meat were4.83%,18.47%and1.24mg/kg respectively（P<0.05）.3．Whether in the process of frozen storage or freezing-thawing cycles, adding antioxidantsBHA and BHT have significantly inhibited fat oxidation. After three months of frozen storage, the TBARS values of minced pork added0.01%BHA and0.01%BHT were0.68mg/kg and0.75mg/kg after three months of frozen storage and were0.47mg/kg and0.51mg/kg afterrepeated freezing and thawing for eight times respectively, which were significantly lowerthan the control group（P<0.05）. The water-holding capacity also increased and changes intexture were smaller than the control. Besides, the composite adding of0.005%(BHA+BHT)had better effect than separately adding（P>0.05）.4．Adding emulsifier monostearin and sucrose esters reduced thawing loss and cooking loss,improved the water-holding capacity of the ground meat and meanwhile fat oxidation wasalso inhibited to some certain and had small degree of texture changes in both the process offrozen storage and repeated freezing-thawing cycles. Further, there’re a lot of water in mincedpork, forming a water-in-oil system. Sucrose esters, which is more hydrophilic, were moreeasily dispersed in ground meat, and therefore had a stronger effect on controlling andimproving the quality of ground meat as compared to monostearin. |
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