Zizyphus jujube-based edible film development by the depolymerization processes

Edible films were developed from jujube (Zizyphus jujube Miller) using depolymerization processes of ultrasound and high-pressure homogenization. A 4.6% (w/w) jujube hydrocolloid was treated by ultrasound (600W, 20 min) or homogenized at high pressure (172 MPa, 6 s) and mixed with whey protein isolate, glycerol, xanthan, and sucrose esters of fatty acids to form film-forming solutions from which films were formed by drying. The film prepared by highpressure homogenization (HPHfilm) produced more homogeneous films without particles than those prepared without depolymerization or with the ultrasound treatment. HPH films possessed the highest tensile strength (4.7MPa), the lowest water vapor permeability (2.9 g.mm/kPa.h.m²), and the most uniform and dense microstructures amongthe films.Flavor profiles of jujube powder and the films were distinguishable. Heat sealstrength and oxygen permeability of the HPH films were 44.4 N/m and 0.025 mL.μm/m²/day/Pa, respectively. Antioxidant activities of jujube power and HPHfilms were not significantly different.