Shakour Nastaran, Khoshkhoo Zhaleh, Akhondzadeh Basti Afshin, Khanjari Ali, Mahasti Shotorbani Peyman
Department of Food Science and Technology North Tehran Branch Islamic Azad University Tehran Iran.
Department of Food Hygiene Faculty of Veterinary Medicine University of Tehran Tehran Iran.
Food Sci Nutr. 2021 Jan 9;9(3):1299-1311. doi: 10.1002/fsn3.2053. eCollection 2021 Mar.
The present study aimed to investigate the impact of polylactic acid (PLA) integrated with nanochitosan (NC) composite film and Ziziphora Clinopodioides essential oil (ZCEO) on oxidative spoilage of rainbow trout fillets during a 9-day refrigeration period. For this purpose, first, six degradable films including T1: PLA, T2: PLA + NC, T3: PLA + NC + 1% ZCEO, T4: PLA + NC + 1.5% ZCEO, T5: PLA + 1% ZCEO, and T6: PLA + 1.5% ZCEO were prepared. Next, the properties of the films were investigated. The results of the mechanical tests showed that ZCEO decreased the tensile strength and increased the elongation at the break of the PLA films. However, adding NC improved the mechanical characteristics of the PLA film. The outcomes of physical tests including moisture content (14.02%), solubility (17.41%), water vapor permeability (1.14 × 10 g s m Pa), and oxygen transmission rate (21.54 cm.mm/m.24 hr) showed that adding 1% ZCEO improved the film physical characteristics. Nevertheless, by adding 1.5% concentration EO to the PLA film, the values of water vapor permeability, porosity (according to the scanning electron microscopy), and turbidity increased and cross-sectional pores were observed. Moreover, the films had high antioxidant properties (84.33%). In the next step, the effects of the mentioned films on the oxidative spoilage of rainbow trout fillets were investigated. The results of the chemical analysis in PLA film with the EO compared with the control treatment revealed the increasing trend of oxidation indices, in general. Moreover, increasing the concentration yielded better results such that all treatments containing EO showed satisfactory results up until the storage period ends. In most cases, adding NC affected the mentioned characteristics positively, and the best results were observed in T4 and then in T3. However, based on economics and the better mechanical and physical properties of T3, the film can be applied as an active packaging in fishery products.
本研究旨在探讨聚乳酸（PLA）与纳米壳聚糖（NC）复合膜及薄荷精油（ZCEO）对虹鳟鱼片在9天冷藏期内氧化变质的影响。为此，首先制备了六种可降解膜，包括T1：PLA、T2：PLA + NC、T3：PLA + NC + 1% ZCEO、T4：PLA + NC + 1.5% ZCEO、T5：PLA + 1% ZCEO和T6：PLA + 1.5% ZCEO。接下来，对这些膜的性能进行了研究。力学测试结果表明，ZCEO降低了PLA膜的拉伸强度，增加了其断裂伸长率。然而，添加NC改善了PLA膜的力学性能。包括水分含量（14.02%）、溶解度（17.41%）、水蒸气透过率（1.14×10 g s m Pa）和氧气透过率（21.54 cm.mm/m.24 hr）在内的物理测试结果表明，添加1% ZCEO改善了膜的物理性能。然而，在PLA膜中添加1.5%浓度的EO后，水蒸气透过率、孔隙率（根据扫描电子显微镜观察）和浊度值增加，并观察到横截面孔隙。此外，这些膜具有较高的抗氧化性能（84.33%）。下一步，研究了上述膜对虹鳟鱼片氧化变质的影响。与对照处理相比，含EO的PLA膜的化学分析结果总体上显示氧化指标呈上升趋势。此外，浓度增加产生了更好的效果，以至于所有含EO的处理在储存期结束前都显示出令人满意的结果。在大多数情况下，添加NC对上述特性有积极影响，在T4中观察到最佳结果，其次是T3。然而，基于经济性以及T3更好的机械和物理性能，该膜可作为水产品的活性包装应用。
