| Frozen storage,a low cost,widly application,hygienic and safe food preservation method,is come from the practice for long time.In this paper,exploring the influences of low voltage electric assisted immersion freezingin proteins,fats,color and texture and water-holding capacity of frozen chicken breast,based on the determination of chicken freezing point,selection of pre-cooling liquid immersion temperature and theparameters of low voltage electric assisted immersion freezing.The purpose of the study is to provide a theory basis for the freezing process and shelf life of frozen chicken meat.1.In the experiments of chooising appropriate refrigerant temperature to pre-cooling the meat up to-1.9?andthe determination of chicken breast freezing point.the results show that:the freezing point of chicken breast is-1.9?,andthe meat,which were precooled by refrigerant?-5?,-10?,-15??respectively,show deep difference??3.9??between meat surface and centre in-15?,however,it is slight difference??0.3??between meat surface and centre,and after pre-cooling,its cooking loss rate?17.21%?,drop loss rate?4.12%?,content of water-soluble proteins?2.02%?,L*?57.33?,hardness?2484.54?,adhesiveness?-99.22?,cohesiveness?0.5222?are reached significant level in comparison the other treatments,when the temperature of refrigerant is-5?.There are no significant differences in treatments among a*,b*,pH,springiness,resilience,chewiness?P>0.05?.2.Freezing chicken breast in different voltage parameters,the results show that whether adding pulser?170Hz?is no important influence in those indexs?P>0.05?.Under the same conditions,the effect of alternating current is better than direct current,but the difference is not significant?P>0.05?.When thevoltage is alternating current 6V,the drip loss rate?5.52%?,cooking lossrate?17.89%?are significantly less than other groups?P<0.05?,and there are no significant difference in comparing with the control group in freezing time and L*?P>0.05?.Generally,alternating current 6V is better for chicken breast in assisted freezing than others.3.Using air cooling freezing,immersion freezing and low voltage electric assisted immersion freezing to froze chicken breast,the results show that:after freezing,the sample's L*,hardness,springiness,adhesiveness,chewiness present a downward trend,and the cooking loss rate,drip loss rate,the soluble protein content are increased gradually.the L*?54.35?,hardness?2262.56?,Springiness?0.763?,chewiness?679.23?,adhesivenes?-133.24?,of conventional air cooling freezing are lower than immersion freezing and low voltage electric assisted freezing?P<0.05?.Different freezing methods have no significant effect on a*,b*,pH,resilience and cohesiveness?P<0.05?.4.Samples,which were frozen by air cooling freezing,immersion freezing and low voltage electric assisted immersion freezing,were 3 months for frozen storage in refrigerantor?-18??,the results show that:with the extension of storage time,the sample's TBARS,TVBN,b*,thawing loss rate,cooking loss rate,drip loss rate,the soluble protein content are increased,and the L*,hardness,springiness,chewinessaredecreased gradually.a*increases initially and decrea ses afterwards,but pHhas opposite trend.After 3months,there are obvious differences in the above indexs?besides pH?between air cooling freezing and immersion freezing and low voltage electric assisted freezing?P<0.05?.The sulpHydryl contents(5.85×10-5 mol/mg.pro),TBARS?0.143 mg/kg?,drop loss rate?5.18%?,L*?52.31?,hardness?1438.78?of low voltage electric assisted freezing exist obvious difference with the sample of air cooling freezing?P<0.05?.Generally,immersion freezing and low voltage electric assisted freezing are better for the quality of frozen meat than air cooling freezing,and the quality of meat frozen by immersion freezing and low voltage electric assisted freezing is no obvice difference?P>0.05?.5.Through the determination of chicken's TVBN and TBARS for 3 months in the frozen storag,the shelf life was deduced by linear equation,and if the TVBN?20 mg/100g?was used to reflect the shelf life,so the results of air cooling freezing,immersion freezing and low voltage electric assisted freezing were about 5.3 months,7.3 months,7.4 months respectively.However if the TBARS?0.5 mg/kg?was used to reflect the shelf life,the results of air cooling freezing,immersion freezing and low voltage electric assisted freezing were about 8.8months,10.6 months,12.1 months respectively.Generally,using the technology of low voltage electric assisted immersion freezing improves the quality and prolong the shelf life of frozen meat to some extent.With the deepening of the research,the techno logy would produce important guiding significance for production. |
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