The inclusion of bioactive substances improved the characteristics of chitosan film or adds new functions to it. Chitosan dissolution is a dilemmatic problem because of the low pH of edible solvents and moderate pH of inedible solvents. Procyanidins, a-amylase and starch were added in the film to enhance the antioxidant ability. Sodium bicarbonate was also employed to adjust the pH of acetic acid solution (solvent). Constituent optimisation of the film-forming solution including the pH of solutions with different amounts of sodium bicarbonate, activity of a-amylase at different pH and addition of appropriate amounts of the three main ingredients was performed. The results showed that the solvent pH should be more than 4. The released amount of reducing sugar (starch hydrolyzate) increased with the increase in the amount of enzyme addition. a-Amylase exhibited a more significant effect than procyanidins, increasing the amount of procyanidins. Full-wavelength scanning, optical test, scanning electron microscopy, X-ray diffraction (XRD), infrared (IR) and differential scanning calorimetry (DSC) were performed to measure the film's characteristics. Even the absorbance peak of procyanidins at 280 nm was increased, following its increasing addition amount; the optical values showed no significant difference. Chitosan film containing starch, a-amylase and procyanidins (CSAPW) had a smoother surface than others. Moreover, the micropores observed on CSAPW can be induced by starch hydrolysis in water immersion. The results of X-ray diffraction (XRD), IR and DSC suggested that water immersion provided the environment for enzymes to hydrolyse the starch. In addition, the hydrolysis function induced the destruction of CSAPW's crystal structure, the change of vibration of hydrogen between chitosan, starch, procyanidins, water and the variation of water evaporation temperature.

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Edible chitosan film incorporated with rutin-bcyclodextrin was developed and characterized. The delivery of rutin was improved via the hydrolyzation function of glucoamylase, and the antioxidant activity of the chitosan film was enhanced by the addition of rutin. Sodium bicarbonate solution at different pHs (pH-adjusting reagent) was employed to afford the mild condition for the incorporated glucoamylase. The enzyme exhibited its hydrolyzation function to improve the release rate of rutin by destabilizing the rutin-b-cyclodextrin complex (RCC) in chitosan film. The optimum pH of glucoamylase was achieved with 5 mL addition amount of 0.5 mol/L sodium bicarbonate solution, and the glucoamylase improved the radical scavenging ratio of chitosan film. The yellowness of chitosan film was enhanced with the addition of RCC solution. The films prepared without water demonstrated & Dongliang Zhang

Aspergillus, being known as a protease producing fungi, is used in Chinese and Korean traditional fermentation. In this paper, Aspergillus 3.084, one of the most common fungi in China fermentation industry, was employed to produce protease and hydrolyze soybean protein, and then the optimum extraction condition of protease was determined by the antioxidant activities of protease extraction solution. The protease was extracted from the culture medium, and performed in hydrolyzing soybean protein isolation. Extract condition of protease, hydrolysis ability of proteases of Aspergillus in hydrolyzing soybean protein isolation and the antioxidant ability of hydrolysate were investigated by detecting enzyme activity, degree of hydrolysis, scavenging activities of OH•, O2•and DPPH•. Maximum protease activity was obtained at 60 min, pH 7.5 and 32°C in extraction step. Optimum protease hydrolyzing time, E/S, temperature and pH for degree of hydrolysis and scavenging activities was 3 h, 6000, 37°C and 7.5, respectively.