ارزیابی ویژگیهاي کاغذهاي کرافت پوششدهی شده با محلولهاي پروتئینی حاوي پودر عصاره چاي با فناوري لایه به لایه خود شکل گیرنده

Layer by layer self-assembly techniqueis one of the newest methods to produce multilayer films relying on the placement of the liquid layers on solid substance. The purpose of this studies is to manufacture multilayer kraftbased on protein biopolymers (zein and whey isolate protein) containing of green tea extract phenolic compounds by utilizing layer by layer self- assembly technique and evaluation antibacterial, physical-mechanical properties and release of phenolic compounds from coated kraft at refrigerator temperature inpH of4.5 and 7. The minimum inhibitory concentrationof green tea powder demonstrates thatEscherichia coli (5mg/ml) compared to Listeria monocytogenes (10mg/ml) is more sensitive. The results of physical properties ofkrafts coated paper showed that thickness, grammage and bulk density increased by coating process. Also, the presence of zein in outer layer caused a significant reduction in WVP and increased air resistance. Evaluation of phenolic compounds release from coated krafts demonstrated that release rate in acidic food stimulant was more than the neutral one. Also, release content of kraft paper with zein as outer layers respect to whey isolated protein was higher in the first days and continued in a longer time. Log reduction value of coated kraft with active bilayer zein against Escherichia coli and Listeria monocytogeneswas 0.25 and 0.06 respectively. According to the results of this study, active zein bilayer kraft is recommended as a carrier of phenolic compounds for the packaging of food products. [ABSTRACT FROM AUTHOR]