聚乳酸基薄膜的制备及其在葡萄保鲜中的应用

Preparation of Poly(Lactic acid)Based Films and Their Application in Preservation of Grapes

目的改善聚乳酸基薄膜的包装性能,探究聚乳酸基薄膜对贮藏期间内葡萄的保鲜效果。方法在聚(L-乳酸)(Poly(L-Lactic Acid),PLLA)主链上通过熔融缩聚的方法引入聚衣康酸丁二醇酯(Poly(Itaconic Acid Butanediol),PBI),制备出聚乳酸共衣康酸丁二醇酯(Poly(L-Lactic Acid Itaconic Acid Butanediol),PLBI),进一步通过迈克尔加成反应在PLLA侧基嫁接3-氨基-1-丙醇(3-Amino-1-Propanol,3AP),制备出具有-OH为侧基的聚乳酸共聚物。探究PLLA/PLBI-3AP薄膜的热学性能、力学性能和气体透过性能。对包装后的葡萄进行贮藏,通过测定贮藏过程中葡萄的气氛组成、感官品质和质量损失率,探究不同包装膜对葡萄保鲜品质的影响。结果与PLLA薄膜相比,PLLA/PLBI-3AP薄膜的Tg降低了19.9℃,断裂伸长率增加为31倍,CO_(2)/O_(2)选择透过比升高到3.0,水蒸气透过率增加了44%。从葡萄保鲜结果表明,PLLA/PLBI-3AP薄膜可有效抑制葡萄果实的腐败变质,提高葡萄的感官品质。结论聚乳酸基薄膜应用于葡萄保鲜,可延长葡萄的货架期至21 d。

The work aims to improve the packaging properties of PLLA-based films and to investigate the effect of PLLA-based films on grape preservation during storage.Poly(L-Lactic Acid Itaconic Acid Butanediol)(PLBI)was prepared by introducing Poly(Itaconic Acid Butanediol)(PBI)on the main chain of Poly(L-Lactic Acid)(PLLA)by melt polycondensation.Poly(lactic acid)copolymer with-OH as a side group were prepared by grafting 3-amino-1-propanol(3AP)onto the side group of PLLA via Michael addition reaction to investigate the thermal,mechanical and gas permeability properties of PLLA/PLBI-3AP film.The grapes were stored after packaging.Through the determination of the composition of the atmosphere,sensory quality and quality loss rate of the grapes in the storage process,the effect of different packaging films on the preservation quality of grapes were explored.Compared with PLLA films,the Tg of PLLA/PLBI-3AP films decreased by 19.9℃,the elongation at break increased by 31 times,the CO_(2)/O_(2) selective permeability ratio increased to 3.0,and the water vapour permeability increased by 44%.The results showed that PLLA/PLBI-3AP films inhibited spoilage and improved sensory quality of grapes.The use of PLLA-based films can extend the shelf life of grapes to 21 days.