柠檬皮/聚乙烯醇/细菌纤维素复合膜的制备及性能研究

Preparation and properties of lemon peel/polyvinyl alcohol/bacterial cellulose composite membrane

该研究首先利用木糖驹形氏杆菌(Taonella mepensis)发酵制备细菌纤维素(bacterial cellulose,BC),然后将其与柠檬皮(lemon peel,LP)、聚乙烯醇(polyvinyl alcohol,PVA)以不同比例混合后制备了一种新型的LP/PVA/BC生物复合膜。分别考察了该复合膜的结构特点、物化特性(热稳定性、厚度、密度、溶胀性、溶解度和孔隙率)、机械性能(抗拉强度和断裂伸长率)以及抑菌活性。结果表明,不同含量的BC对复合膜的微观结构有显著影响,红外光谱和X-射线衍射结果表明,成功地制备了LP/PVA/BC复合膜。复合膜中添加BC可显著降低膜的溶胀性(70.94%~76.68%),提高热稳定性,并对其孔隙率产生影响。同时,还可提升膜的抗拉强度(93.41%~341.57%)和断裂伸长率(4.11%~44.03%)。采用物化特性和机械性能较优的4.8%BC复合膜进行抑菌实验,结果显示该复合膜对沙门氏菌、枯草芽孢杆菌、大肠杆菌及金黄葡萄球菌的抑制率分别为35.93%、48.98%、62.12%和94.93%。以上结果表明,该复合膜显示了较优的物化特性、机械性能和抑菌特性,具有在食品包装材料领域的应用潜力。

In this study,bacterial cellulose(BC)was prepared by fermentation with Taonella mepensis firstly and then mixed with lemon peel(LP)and polyvinyl alcohol(PVA)in different proportions to obtain a new kind of LP/PVA/BC biocomposite membrane.The structural characteristics,physicochemical properties(thermal stability,thickness,density,swelling,solubility,and porosity),mechanical properties(tensile strength and elongation at break),and antibacterial activity of the composite membrane were investigated.Results showed that the different content of BC had a significant effect on the microstructure of the composite membrane by the scanning electron microscopy analysis.The results of Fourier transform infrared spectrometer and X-ray diffraction showed that the LP/PVA/BC composite film had been successfully prepared.The addition of BC could significantly reduce the swelling property(from 70.94%to 76.68%),improve the thermal stability,affect the porosity of the composite membrane,and also increase the tensile strength(from 93.41%to 341.57%)and the elongation at break(from 4.11%to 44.03%)of the membrane.The inhibition rates of 4.8%BC composite membrane against Salmonella,Bacillus subtilis,Escherichia coli,and Staphylococcus aureus were 35.93%,48.98%,62.12%,and 94.93%,respectively.The above results indicated that the composite membrane exhibited excellent physicochemical,mechanical,and antibacterial properties,and had high potential for application in food packaging.