超声波微波协同改性乳清蛋白/壳聚糖可食膜工艺优化

    Process optimization of whey protein concentrate-chitosan edible films modified by ultrasonic/microwave assisting treatment

    • 摘要: 为研究新型高性能可食膜及制备方法采用浓缩乳清蛋白(whey protein concentrate,WPC)和壳聚糖(chitosan,CS)为成膜基材,制备出可食膜,利用超声波微波协同作用对可食膜进行改性,试验结果表明超声波微波协同改性后的可食膜具有较低透气性;并研究成膜材料配比、山梨醇质量浓度、pH值和超声波微波协同作用时间对可食膜水蒸气透过系数(water vapor permeability,WVP)、氧气透过率(oxygen permeability,OP)抗拉强度(tensile strength,TS)、断裂伸长率(elongation,E)和透光率(transmittance,T)的影响。试验结果表明成膜材料配比WPC∶CS=5.8∶6.2、山梨醇质量浓度0.021 g/mL、pH值5.13、超声波微波协同作用5 min时,此时制备的可食膜透气性较低,且具有较好的物理性质,水蒸气透过系数为1.22×10-13 g/(cm·s·Pa),氧气透过率为1.29×10-5 cm3/(m2·d·Pa)。该文研究成果可为可食膜的研发提供新的参考。

       

      Abstract: Abstract: To preparing a new high-performance edible film, the edible films were made from whey protein concentrate (WPC) and chitosan (CS). The modified treatment with assistance of ultrasonic/microwave group was carried out. According to pre-test, the optimal ultrasonic power 90 W, microwave power 300 W, modified temperature 30℃, the edible films were prepared using WPC: CS=6:6, namely, whey protein concentrate 1.5 g and chitosan (CS) 1.5 g, sorbitol concentration 3 g, pH value 5. The results showed that water vapor permeability (WVP) of the edible films modified with assistance of ultrasonic/microwave was 1.18×10-13 g/(cm·s·Pa), lower than that of the control group (1.64×10-13 g/(cm·s·Pa)), in other words, water vapor permeability modified with assistance of ultrasonic/microwave group, was reduced by 27.9%, by contrast with ultrasound and microwave group water vapor permeability was reduced by 13.4% and 8.9%, respectively; oxygen permeability (OP) of the edible films modified with assistance of ultrasonic/microwave was 1.09×10-5 cm3/(m2·d·Pa), which was lower than 2.1×10-5 cm3/(m2·d·Pa) of the control group, namely, oxygen permeability was reduced by 48.1%, by contrast with ultrasound and microwave group oxygen permeability was reduced by 27.3% and 25.9%, respectively. The results showed that ultrasonic/microwave assisting treatment can reduce water vapor permeability and oxygen permeability of blend films of whey protein concentrate and chitosan.The paper analyzed the effects of factors on the tensile strength, elongation at break, transmittance, water vapor permeability and oxygen permeability by single factor experiments. Those factors included film-forming ratio WPC:CS, adding quantity of sorbitol (as plasticizer), the pH, and the time of ultrasonic/microwave assisting treatment. The optimal technology parameters were WPC:CS=5.8:6.2, sorbitol concentration 0.021 g/mL, pH value 5.13, and ultrasonic/microwave assisting treatment time 5 min; and under the conditions, the blend films exhibited good physical properties, and transmittance was 60.23%, WVP was 1.22×10-13 g/(cm·s·Pa), OP was 1.29×10-5 cm3/(m2·d·Pa), tensile strength was 20.53 MPa and elongation at break was 58.91%. According to the optimization results, WPC/CS edible films were prepared and performance test was executed. The measured average values from three parallel verification experiments were: Tensile strength (TS) 23.45 MPa, water vapor permeability 1.34×10-13 g/(cm·s·Pa), elongation at break 57.6%, oxygen permeability 1.15×10-5 cm3/(m2·d·Pa) and transmittance 61.5%. The relative error of transmittance was minimum which was only 2.07%, and the relative error of water vapor permeability was maximum which was 5.65%. It was found that the relative error experiment results can be used to predict. The results can provide a reference for the development of a new edible film.

       

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