含五倍子水提物的魔芋葡甘聚糖/乙基纤维素膜理化性和抗菌性研究

Physical-mechanical and antimicrobial properties of konjac glucomannan/ethyl cellulose film incorporated with gallic water extract

以魔芋葡甘聚糖(KGM)和乙基纤维素(EC)为基材,添加五倍子提取物制备可食性抗菌膜。测定了复合膜的拉伸强度、断裂伸长率、水蒸汽透过率及阻氧性,并将其应用于生鲜鱼片保鲜包装,测定了储藏期内鱼肉的p H、挥发性盐基氮(TVB-N)值和菌落总数。结果表明,KGM/EC复合膜拉伸强度随五倍子水提物添加量的增大而显著降低,当五倍子水提物添加量大于15%时,其拉伸强度无显著变化(p<0.05)。随着五倍子水提物添加量从0%增加至20%时,复合膜断裂伸长率显著性增加且水蒸汽透过率显著性降低(p<0.05),另外,膜的阻氧性显著性提高(p<0.05)。采用添加20%五倍子提取物的复合膜(w/w)用于鱼片冷藏包装,鱼片保鲜的主要参考指标(p H、TVB-N值和菌落总数)与未用膜包装组和未添加五倍子复合膜组相比,均有显著性差异(p<0.05)。以菌落总数为参考指标,添加20%五倍子含量的复合膜包装的鱼片与未用膜包装鱼片相比,其4℃储藏条件下货架期延长了3 d。魔芋葡甘聚糖-乙基纤维素复合抗菌膜在食品保鲜上具有一定的应用前景。

Edible antibacterial film was prepared by adding gallnut water extract into konjac glucomannan（ KGM） /ethyl cellulose（ EC） sol.The tensile strength（ TS）,elongation at break（ EAB）,water vapor permeability（ WVP）,and oxygen barrier properties of composite films were measured.The composite films were used to package fish fillet stored at 4 ℃.The p H,total volatile basic nitrogen（ TVB- N）,and total numbers of colonies were tested at 0,2,7,10 and 15 day respectively to determine effects of edible antibacterial films on the storage of fish fillet. The results showed that with the increase of gall water extract content in composite film,TS of composite films decreased significantly（ P〈0.05）,when the contents of gallnut was more than 15%,TS showed no significantly difference.With the content of gallnut water extract content increasing from 0% to 20%,EAB and WVP were significantly increased and decreased（ P〈0.05）,respectively.Moreover,oxygen barrier properties were enhanced significantly（ P〈0.05）.KGM / EC films incorporated with 20% gallic water extract were used to fish fillet packaging,the values of p H,TVB- N,and total numbers of colonies of fish fillet had significantly difference,respectively,compared with fish fillet and fish fillet packaged with films without gallnut during storage（ P〈0.05）. Considering the total numbers of colonies as a reference index,KGM / EC composite film containing 20% gallnut water extract could prolong the shelf life of fish fillet stored at 4 ℃ for 3 days,compared with fish fillet without film packaging. Konjac glucan-mannan- ethyl cellulose antibacterial membrane had a certain application prospect in food preservation.