Coating on postharvest fruits is a new emerging technique to extend the shelf-life of fruits.In this experiment,tangerine fruits were first dipped in chitosan (CS) and chitosan/nanodiamond (CS/ND) (ND content was 2％) composite coating solution for 2-3 min.After drying,they were stored with the untreated group (CK) and commercial fresh-keeping agent (FA) treated group at 10 ± 3 ℃,a relative humidity of 65％ ± 10％.Changes of weight loss,ascorbic acid content,total soluble solids content,titratable acid content,internal CO2 concentration and rotting rate of fruits were monitored.Moreover,the surface morphologies of peels and coatings of fruits were investigated periodically during storage.Results showed that CS/ND coating decreased the rotting rate of fruits during the whole storage,while CS coating was effective only during the first 7 days.Fruits with CS/ND coating showed higher content of absorbic acid and total soluble solids at the first stage of storage,but had higher content of titratable acid during the whole storage,compared to other groups.Moreover,fruit coated by CS or CS/ND also presented higher CO2 concentration.These results revealed that CS/ND coating effectively extended the storage time and maintained qualities of tangerine.Micropores were observed on the coatings layers with the increasing of storage time.Additional ND in the coating enhanced the stability and delayed the appearance of micropores,therefore extended the preservation time.%对采后水果进行涂膜是延长其贮藏期的新型保鲜技术.试验将红桔分别在纯壳聚糖涂膜液(CS)和壳聚糖/纳米金刚石(CS/ND)复合涂膜液(纳米金刚石质量分数为2％)中分别浸泡浸泡2～3 min后晾干,置于温度为(10±3)℃,湿度为(65±10)％的环境中贮藏,并与商业保鲜剂(FA)处理组和未处理组(CK)进行对照.定期测定红桔的失重率、抗坏血酸含量、可溶性固体含量、可滴定酸含量、内部二氧化碳浓度以及腐烂个数,并采用扫描电镜(SEM)观测果皮的微观形貌变化.结果表明,CS/ND涂膜使红桔的腐烂率在整个贮藏期间均显著降低,但CS涂膜仅在前7d有效.CS/ND涂膜组的抗坏血酸和可溶性固形物含量在贮藏前期较高,可滴定酸含量则在整个贮藏期间均可维持较高水平,且CS和CS/ND涂膜组内部CO2浓度均高于其余2组.说明复合涂膜能有效地延长果实的贮藏期,保持较好的果实品质.随贮藏时间的延长,涂膜表面均出现微孔.在涂膜中添加纳米金刚石可提高涂膜稳定性,延缓微孔的出现,从而保鲜效果更持久.
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