Effect of pH on physical properties of edible films from faba bean protein

摘要

Natural polymers derived from natural sources like proteins of plants, offer great opportunities for the food industry due their biodegradability and ability to supplement nutritional value of foods. In this study, the effect of different values of pH (7.0, 8.5 and 10.0) of film forming solution on physical properties of faba bean edible films was investigated. The edible films were prepared by the solution casting method with 3% w/w of faba bean protein concentrate (FPC) and glycerol (50%, w/w of FPC) as plasticizer. Films were evaluated for thickness, water content, soluble matter, protein solubility, puncture strength, elongation, water vapor permeability (WVP) and color. The pH value did not have significant influence on moisture content and thickness. The total soluble matter and protein solubility showed a significant increase as pH forming solution increased from 7.0 to 10.0. However, edible films obtained had a good stability since polymer did not exceed 26% of total solubility film, while the protein solubility was not greater than 3%. At alkaline conditions the edible films showed the lowest WVP (0.96×10~(-10) g mm/kPa h m~2) and the highest values of puncture strength (17.92 MPa) and elongation (44.43%). Edible protein films from faba bean had a lightly yellow color.