肉桂精油-壳聚糖涂膜协同气调包装对冷鲜肉品质的影响

Combined effect of cinnamon essential oil-chitosan coating and modified atmosphere packaging on the quality of chilled meat

为了延长冷鲜肉的货架期,以圆香黑猪肉为原材料,设置4个贮藏处理[处理组A:肉桂精油-壳聚糖涂膜+聚乙烯(polyethylene,PE)保鲜膜包装+0℃贮藏;处理组B:稀冰乙酸浸渍+聚偏二氯乙烯(polyvinyl dichloride,PVDC)低氧气调(50%CO2+35%O2+15%N2)包装+0℃贮藏;协同组:肉桂精油-壳聚糖涂膜+PVDC低氧气调(50%CO2+35%O2+15%N2)包装+0℃贮藏;对照组:稀冰乙酸浸渍+PE保鲜膜包装+0℃贮藏],通过考察冷鲜肉(猪背最长肌)贮藏期的pH、总挥发性盐基氮含量、菌落总数、假单胞菌数、热杀索丝菌数、红度值a*、弹性、汁液损失率等理化及生物指标,探究不同处理条件对冷鲜肉贮藏保鲜效果的影响,并对其贮藏期间品质指标进行主成分分析。结果表明:与对照组相比,处理组A、处理组B及协同组均可有效抑制pH、总挥发性盐基氮含量、菌落总数、假单胞菌数、热杀索丝菌数、汁液损失率的上升,同时可显著减缓红度值a*和弹性的下降(P<0.05),且贮藏后期(7~9 d),协同组的保鲜效果显著优于处理组A、B(P<0.05);与对照组比较,协同组可明显改善圆香黑猪肉贮藏品质,延长其货架期约4 d。通过对检测的8个指标进行主成分分析可知,pH、总挥发性盐基氮含量、菌落总数、假单胞菌数、热杀索丝菌数、汁液损失率之间呈显著正相关,但均与红度值a*及弹性呈显著负相关(P<0.01)。8个检测指标可简化为1个主成分,其方差贡献率为96.557%,能较好地反映原始信息,其中第1主成分中贡献率大小依次为假单胞菌数>热杀索丝菌数>菌落总数>汁液损失率>pH>弹性>总挥发性盐基氮含量>红度值a*,主要反映了冷鲜肉贮藏期间微生物增殖及蛋白质水解氧化程度;建立的关于第1主成分的线性回归函数为Y1=0.128X1+0.126X2+0.128X3+0.129X4+0.129X5-0.123X6-0.126X7+0.128X8。上述结果可为冷鲜肉的低温保鲜提供数据支持及参考。

In order to extend the shelf life of chilled meat,the effects of preservative treatment conditions on the quality of chilled meat were studied.Taking the meat from Yuanxiang black pigs as raw materials,the chilled meat(pork Longissimus dorsi muscle)were stored at 0℃with the treatments of cinnamon essential oil-chitosan coating and polyethylene(PE)fresh-keeping film packaging(treatment group A),impregnated in dilute glacial acetic acid and polyvinyl dichloride(PVDC)low-oxygen conditioning(50%CO2+35%O2+15%N2)packaging(treatment group B),cinnamon essential oil-chitosan coating and PVDC low-oxygen conditioning(50%CO2+35%O2+15%N2)packaging(synergistic group),and impregnated in dilute glacial acetic acid and PE freshkeeping flim packaging(control group).The physicochemical and biological indicators were investigated,including pH value,total volatile basic nitrogen content,total numbers of colony,the numbers of Pseudomonas and Brochothrix thermosphacta,redness value(a*),elasticity and juice loss rate during storage,and the principal component analysis was carried out.The results showed that:compared with the control group,the treatment group A,treatment group B and synergistic group could effectively inhibit the increase of pH,total volatile basic nitrogen content,total numbers of colony,Pseudomonas,B.thermosphacta,and juice loss rate;and they could significantly slow down the decrease of a*and elasticity(P<0.05).In the late storage period(7-9 d),the freshkeeping effect of synergistic group was significantly better than that of the treatment group A and B(P<0.05).Compared with the control group,the synergistic group could significantly improve the storage quality of chilled meat and prolong its shelf life for about 4 days.Through the principal component analysis of the eight indicators,the total volatile basic nitrogen content,total numbers of colony,pH,juice loss rate,the numbers of Pseudomonas and B.thermosphacta showed a positive correlation among these indicators.The above indicators were negatively correlated with a*and elasticity(P<0.01).The eight test indicators could be simplified into one principal component,and the variance contribution rate was 96.557%,which could better reflect the original information.The order of contribution rate in the first principal component was Pseudomonas count>B.thermosphacta count>total numbers of colony>juice loss rate>pH>elasticity>total volatile basic nitrogen content>a*.The first principal component mainly reflected the degree of microbial proliferation and protein hydrolysis and oxidation of the chilled meat during storage.The linear regression function for the first principal component was Y1=0.128X1+0.126X2+0.128X3+0.129X4+0.129X5-0.123X6-0.126X7+0.128X8,which can provide data support and reference for the low temperature preservation of chilled meat.