含紫苏精油Pickering乳液活性膜的表征及其对冷鲜牛肉品质的影响

Characterization of active film containing Perilla essential oil Pickeringemulsion for improving storage of chilled beef

该研究以大豆分离蛋白(soy protein isolate, SPI)和壳聚糖纳米粒子(chitosan nanoparticles, CSNPs)为乳化剂制备负载紫苏精油(perilla essential oil, PEO)的Pickering乳液(SPI-CSNPs-PEO Pickering, SCEO),并测定了其粒径、Zeta电位和乳化指数,以进一步验证乳液的稳定性。结果表明,随着油相体积分数的增加,Pickering乳液的Zeta电位的绝对值和乳化指数增加,粒径减小。当油相体积分数为80%时粒径更小,乳滴分散均匀,体系更稳定。以细菌纤维素(bacterial cellulose, BC)和聚乙烯醇(polyvinyl alcohol, PVA)为基材,加入不同体积分数(1%、1.5%、2%、2.5%)的Pickering乳液制备BP/SCEO复合膜。红外光谱和扫描电镜结果显示,SCEO增加了膜表面的粗糙程度,与基膜之间形成氢键相互作用;差示扫描量热法分析表明,复合膜的热稳定性提高。此外,SCEO的加入降低了复合膜水蒸气透过率和拉伸强度而升高了断裂伸长率。其中,BP/SCEO3的性能最好。该方法在一定程度上降低了冷鲜牛肉的菌落总数,延缓了氧化酸败,并将其保质期延长了6 d。因此,负载PEO Pickering乳液的复合膜是一种很有前景的食品包装材料。

This study aimed to prepare Pickering emulsions(SCEO)loaded with perilla essential oil(PEO)using soy protein isolate(SPI)and chitosan nanoparticles(CSNPs)as emulsifiers.The particle size,zeta-potential,and emulsification index were determined to confirm the stability of the emulsions.Results showed that the absolute value of the zeta-potential and emulsification index of Pickering emulsion increased and the particle size decreased as the volume fraction of the oil phase increased.The particle size was smaller when the volume fraction of the oil phase was 80%,the emulsion droplets were uniformly dispersed,and the system was more stable.The composite films were prepared by adding different amounts(1%,1.5%,2%,2.5%,volume fraction)of Pickering emulsion with bacterial cellulose(BC)and polyvinyl alcohol(PVA)as substrates.The presence of SCEO increased the surface roughness of the films and formed hydrogen bonding interactions with the base film was shown by Fourier transform infrared spectroscopy and scanning electron microscope.The differential scanning calorimetry analysis showed that the thermal stability of the composite film was improved.Moreover,SCEO was incorporated to reduce the water vapor permeability and tensile strength of the composite film and increase the elongation at break.Interestingly,BP/SCEO3 has the optimal performance.It reduced the total viable count of chilled beef to a certain extent,delayed oxidative rancidity,and extended its shelf life by 6 days.Therefore,PEO Pickering emulsion-loaded composite films are a promising material for food packaging.