Incorporated α-amylase and starch in an edible chitosan–procyanidin complex film increased the release amount of procyanidins

Abstract

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.

The physicochemical properties of chitosan prepared by microwave heating

“…The XRD patterns and I CR % of commercially available chitin and chitosan, the chitosan produced by MW or WB for 10 min, 30 min, 60 min, 120 min, and 240 min (denoted as MW10, WB10, MW30, WB30, and so on, respectively), are presented in Figure 5. The spectra of chitosan WB and chitosan MW have the same positions of peaks (2θ = 11.92–12.29° and 2θ = 20.01–20.56°) as the commercial chitosan, concurring with the results given by Yen, Yang, and Mau (2009 and Zhang et al (2017), although one method took 240 min, while the other required 60 min.…”

Preparation and characterization of chitosan membranes

“…4 shows that the X-ray diffraction patterns of the neat chitosan and of those formed by means of the different regenerating agents. As can be seen from the figure, chitosan has three characteristic absorption peaks at 2 θ = 10.22°, 19.9° and 20.5°, 27 while the peaks of the ethanol-regenerated chitosan are observed at 2 θ = 10.2°, 19.02° and 21.2°. Thus, the X-ray diffraction profiles of the two films are basically the same, as the intensity of the peaks is also very close.…”

Effects of different alcohol and ultrasonic treatments on thermal and structural properties of zein‐starch sodium octenyl succinate composite nanoparticles

“…There are major heat absorption peaks in the interval between 80–180°C, which are due to the evaporation of bound water from the polymer (Zhang et al., 2017). The shift of the heat absorption peaks to the right indicates that the interaction between SSOS and zein molecules destroys the original structure.…”

“…The results are shown in Table 2 and reveal that ultrasonic treatment for 10 min improves the stability of ZSPs nanoparticles, and the thermal stability of EZSPs particles is greater than IZSPs particles. There are major heat absorption peaks in the interval between 80-180 • C, which are due to the evaporation of bound water from the polymer (Zhang et al, 2017). The shift of the heat absorption peaks to the right indicates that the interaction between SSOS and zein molecules destroys the original structure.…”