Chitosan film incorporated with Garcinia atroviridis for the packaging of Indian mackerel (Rastrelliger kanagurta)

ABSTRACT Herbs and spices, having antimicrobial effect, can be incorporated into edible films, to extend product shelf life and the reduce the risk of microbial growth on food. The aim of this study is to develop chitosan film incorporated with Garcinia atroviridis, also known as ‘asam gelugur’, ‘asam gelugo’, or ‘asam keping’. The film with different concentrations of Garcinia atroviridis (1 to 5% v/v) with chitosan (1.5% w/v) were investigated for its physical, mechanical and antibacterial properties. With the increase of Garcinia atroviridis extract incorporated, water solubility of the films increases (from 21.17 to 53.61%). Increase of Garcinia atroviridis incorporated into chitosan film also increase the total color difference. Film with higher concentration of Garcinia atroviridis extract produced thicker film compared to the film without extract (from 0.048 to 0.143 mm). The film with 5% (v/v) Garcinia atroviridis possessed low tensile strength (3.28 MPa) and elongation at break (13.90%). Young’s modulus was decreased in value (from 0.72 to 0.24 MPa) as the higher concentration of Garcinia atroviridis extract was added. High Garcinia atroviridis extract (5% v/v) in the chitosan films demonstrated greater inhibitory activity against the bacteria strains (Pseudomonas aeruginosa, Bacillus subtilis and Staphylococcus aureus). With the edible film of 5% (v/v) Garcinia atroviridis applied, the Indian mackerel was found to have a longer shelf life (3.5 days) as compared to the control (2.5 days).摘要 具备抗菌活性的药草与香料可被掺入可食用膜中，以延长产品货架期并降低食品表面微生物滋生风险。本研究旨在开发添加大叶藤黄（Garcinia atroviridis，俗称‘asam gelugur’、‘asam gelugo’或‘asam keping’）的壳聚糖（chitosan）可食用膜。本研究考察了添加不同浓度（1%~5% v/v）大叶藤黄提取物与1.5% w/v壳聚糖的复合膜的物理、机械及抗菌性能。随着大叶藤黄提取物添加量的提升，复合膜的水溶性从21.17%升高至53.61%；总色差也随提取物添加量增加而增大。与未添加提取物的膜相比，大叶藤黄提取物浓度更高的复合膜厚度更厚（0.048 mm~0.143 mm）。添加5%（v/v）大叶藤黄的复合膜表现出较低的拉伸强度（3.28 MPa）与断裂伸长率（13.90%）；随着提取物浓度升高，复合膜的杨氏模量从0.72 MPa降至0.24 MPa。添加5%（v/v）大叶藤黄的壳聚糖膜对铜绿假单胞菌（Pseudomonas aeruginosa）、枯草芽孢杆菌（Bacillus subtilis）与金黄色葡萄球菌（Staphylococcus aureus）均表现出更强的抑菌活性。将该5%（v/v）大叶藤黄可食用膜应用于印度鲭鱼后，其货架期相较于对照组（2.5天）延长至3.5天。