College of Food Science, Sichuan Agricultural University, Yaan 625014, China.
College of Food Science and Technology, Sichuan Tourism University, Chengdu 610100, China.
Molecules. 2019 Apr 10;24(7):1408. doi: 10.3390/molecules24071408.
In this study, we fabricated polyvinyl alcohol (PVA)/chitosan (CS) bilayer films by casting and investigated the effects of preparation conditions and CS content (2, 2.5, or 3 wt.%) on the ability of these films to preserve packaged strawberries. The best performance was achieved at a CS loading of 2.5 wt.% (ultrasound time, 25 min); the strain and stress values were 143.15 ± 6.43% and 70.67 ± 0.85 MPa, respectively, oxygen permeability was 0.16 ± 0.08 cm²·m²·day·MPa, water vapor permeability was 14.93 ± 4.09 g·cm·s·Pa, and the shelf life of fresh strawberries packaged in the PVA/CS 2.5 wt.% bilayer film was determined to be 21 days at 5 ± 2 °C and a relative humidity of 60 ± 5%. Treatment with PVA/CS bilayer films prevented the decrease in the firmness of strawberries during storage (21 days). The evaluated physicochemical parameters (weight loss, decay, firmness, titratable acidity, soluble solid content, ascorbic acid content, and color) indicated that treatment with PVA/CS bilayer films led to better maintenance of the fruit quality. We believe that our study makes a significant contribution to literature because it paves the way to the fabrication of smart packaging materials and facilitates the commercialization of fresh strawberries as an important health food.
在这项研究中，我们通过浇铸法制备了聚乙烯醇（PVA）/壳聚糖（CS）双层膜，并研究了制备条件和 CS 含量（2、2.5 或 3wt.%）对这些膜包装草莓保鲜能力的影响。在 CS 负载量为 2.5wt.%（超声时间 25 分钟）时表现出最佳性能；应变和应力值分别为 143.15±6.43%和 70.67±0.85MPa，氧气渗透率为 0.16±0.08cm²·m²·day·MPa，水蒸气渗透率为 14.93±4.09g·cm·s·Pa，用 PVA/CS 2.5wt.%双层膜包装的新鲜草莓的货架期在 5±2°C 和相对湿度 60±5%下确定为 21 天。用 PVA/CS 双层膜处理可防止草莓在贮藏过程中硬度下降（21 天）。评估的物理化学参数（失重、腐烂、硬度、滴定酸度、可溶性固形物含量、抗坏血酸含量和颜色）表明，用 PVA/CS 双层膜处理可更好地保持果实品质。我们相信我们的研究对文献做出了重要贡献，因为它为制造智能包装材料铺平了道路，并促进了新鲜草莓作为一种重要的健康食品的商业化。
