将橘皮提取液还原制备的纳米银,按照0.5％,1.0％,2.0％的质量分数分别添加到壳聚糖溶液中,制成复合涂膜液,对鸡蛋进行涂膜,分别记为CS/Ag 0.5、CS/Ag 1.0、CS/Ag 2.0,纯壳聚糖涂膜组记为CS.将涂膜组与未处理组(CK1)、清水清洗组(CK2)置于温度25℃、相对湿度70％的条件下贮藏.定期对鸡蛋内容物的外观、失重率、气室高度、相对密度、哈夫单位(HU)、蛋清pH、蛋黄指数(YI)、鸡蛋内容物菌落总数以及蛋壳外表面微观形貌等指标进行测定.结果表明,纳米银在涂膜中的质量分数为1.0％时,涂膜鸡蛋可维持较低的失重率和气室高度,稳定的蛋清pH值,较高的相对密度、哈夫单位和蛋黄指数值.同时,该复合涂膜可显著抑制鸡蛋内容物中微生物的滋生,并能有效维持涂膜结构在贮藏期间的稳定性,从而提高保鲜效果的持续性.因此,CS/Ag 1.0组鸡蛋在25℃时的货架期可长达79 d,相较于CS组延长了至少34 d,而相较于CK1和CK2则至少延长了69 d.%Nano-silver particles were prepared using the extract of cit rus peels were added to chitosan solutions with weight ratios of 0.5％,1.0％,and 2.0％,separately,as the composite coating solu tions.Eggs were coated two tiues by the neat chitosan solution and composite coating solutions,separately,and was designated as CS,CS/Ag 0.5,CS/Ag 1.0,and CS/Ag 2.0,accordingly.They were stored with the two control groups (untreated eggs (CK1) and eggs washed by water (CK2) at 25 ℃ with the relative humidity of 70％.The appearance of internal content,weight loss,air cell height,spe cific gravity,albumen pH,Haugh unit (HU),yolk index (YI),total plate count of internal content and the micro-morphologies of the egg outer-shells were measured regularly during the storage.The results showed that,the coated eggs presented low weight loss and air cell height,stable albumen pH,high values of specific gravity,HU and YI when coated with 1.0％ nano-silver.Furthermore,it was found that the composite coating containing nano-silver could effec tively inhibit the microbial growth in the internal content of eggs,and stabilized the structure of coating resulting in enhanced durability of preservation effects.Therefore,the shelf life of CS/Ag 1.0 was as long as 79 days at 25 ℃,which was at least 34 days longer than that of CS,and 69 days longer than those of CK1 and CK2.
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