天然保鲜剂对蟠龙菜贮藏特性的影响

Effect of Natural Preservatives on the Storage Characteristics of Panlongcai,a Traditional Steamed Dish in Zhongxiang,Hubei

为提高蟠龙菜的贮藏品质并对其贮藏特性变化进行研究,选取迷迭香提取物、茶多酚、香芹酚、ε-聚赖氨酸(ε-poly-L-lysine,ε-PL)和乳酸链球菌素(nisin)作为保鲜剂,采用牛津杯法对蟠龙菜中分离纯化的腐败菌进行抑菌圈实验,筛选出抑菌效果好的保鲜剂应用于蟠龙菜中,测定添加不同保鲜剂的蟠龙菜在4℃贮藏0、5、10、15、20、25 d后的微生物、感官、理化和风味品质。结果表明:ε-PL、Nisin和香芹酚对蟠龙菜中优势腐败菌抑制效果较好,在贮藏过程中,添加香芹酚和ε-PL组pH值下降幅度较小,分别为0.11和0.06;通过分析总挥发性盐基氮含量和硫代巴比妥酸反应物值的变化,发现香芹酚和Nisin可以有效抑制蟠龙菜4℃贮藏过程中脂肪氧化和挥发性盐基氮的生成;使用偏最小二乘回归及熵权法结合加权灰色关联度对4项贮藏指标进行分析,贮藏25 d时,加权灰色关联度最高的是添加Nisin(0.4059)和香芹酚(0.3876)组,表明Nisin和香芹酚的添加能有效改善蟠龙菜贮藏过程中的微生物及理化品质;Nisin组和ε-PL组微观结构的孔隙较少且结构更为致密;电子鼻分析得出添加香芹酚的蟠龙菜风味相较于对照组差异较大;感官评价得出添加香芹酚会显著降低蟠龙菜的风味及可接受性评分(P<0.05)。因此,添加Nisin能在不改变蟠龙菜风味的同时有效抑制冷藏过程中微生物的生长繁殖并减少理化指标的变化,提高其贮藏品质。

To improve the storage quality and to study the changes in storage characteristics of Panlongcai,the bacteriostatic effects of rosemary extract,tea polyphenols,carvacrol,ε-poly-L-lysine(ε-PL)and nisin on spoilage bacteria isolated from Panlongcai were tested by the Oxford cup method.Panlongcai added with the preservatives with good bacteriostatic activity were stored at 4℃and evaluated for microbiological,organoleptic,physicochemical and flavor qualities after 0,5,10,15,20 and 25 days.The results showed thatε-PL,nisin and carvacrol had good inhibitory effects on the dominant spoilage bacteria in Panlongcai.During the storage process,the pH decrease was smaller in the carvacrol andε-PL addition groups,0.11 and 0.06,respectively.Carvacrol and nisin effectively inhibited lipid oxidation as assessed by thiobarbituric acid reactive substances(TBARS)value and total volatile basic nitrogen(TVB-N)generation.The total bacterial count(TBC),pH,TBARS and TVB-N data were analyzed by the combined use of partial least squares regression(PLSR),entropy weighting method and weighted grey correlation,and it was found that the highest weighted grey correlation occurred upon the addition of nisin(0.4059)and carvacrol(0.3876)after 25 days of storage,which indicates that the addition of nisin and carvacrol could effectively improve the microbiological and physicochemical qualities of Panlongcai during the storage process.Both nisin and carvacrol groups exhibited a less porous and denser microstructure.Electronic nose analysis showed a greater difference in the flavor of Panlongcai with the addition of carvacrol compared to the control group.Sensory evaluation showed that the addition of carvacrol significantly reduced the flavor and acceptability of Panlongcai(P<0.05).In conclusion,the addition of nisin could effectively inhibit the growth and reproduction of microorganisms and reduce the changes of physicochemical indexes during cold storage without altering the flavor of Panlongcai,and improve its storage quality.