Cellulosic films reinforced by chitosan-citric complex for meat preservation: Influence of nonenzymatic browning

Microbiological, physicochemical and structural characteristics of natural salted casings treated with antibacterial agents

“…The bands peaked at around 1719 cm −1 , which was relative to the C‐O stretching of citric acid, but no C‐O stretching signal of citric acid was observed between 1750 and 1700 cm ‐1 in Fig. 5A, indicating that citric acid was not fixed in the salted casing (Song et al ., 2021). The absorption bands for the typical structure of chitosan oligosaccharide in the FTIR spectra peaked between 1600 and 1650 cm −1 because of amide II (N‐H) and amide I (C = O), and 1380 cm −1 due to the distorting vibration of C‐CH 3 .…”

“…Nisin solutions were prepared by dissolving 0.01, 0.02 and 0.03 g of nisin in 100 g of sterile water. The selected concentration of citric acid, tea polyphenols and nisin was based on the Chinese National Standard (GB2760‐2014), and the concentration of chitosan oligosaccharide was based on previous studies (Rao et al ., 2008; Bhat et al ., 2021; Song et al ., 2021). Next, 10 g casings were soaked in 10 g antibacterial agent solution, and then placed in the CNC ultrasonic cleaner (KQ‐600DE; Kunshan Ultrasonic Instrument Co., Ltd., Suzhou, China) at 100 Hz for 5 min (Feng et al ., 2014).…”

Poly(vinyl alcohol) antibacterial films containing cross‐linked chitosan‐citric and photosensitive curcumin

“…Prior to SEM observation, each film was placed on a stub and coated by a thin layer of gold. 31 2.3.9 | Atomic force microscope (AFM)…”

“…The surface images of PVA-CS-Cur x films under vacuum-drying at 80 C were obtained by using an atomic force microscope (AFM, Oxford Cipher VRS, UK). 31 2.3.10 | Oxygen transmission rate (OTR) and oxygen permeability (OP)…”

“…30 When adding chitosan-citric into PVA structure and increasing the drying temperature of film preparation, the water-resistant and oxygen-barrier capabilities of PVA films can be improved, probably owing to the existence of cross-linked ionic bonds and the nonenzymatic browning of polysaccharide occurring at high temperature. 31 In our present work, the effect of nonenzymatic browning of chitosan-citric on the water resistance, thermal stability and tensile strength of PVA films were investigated. The synergistic antibacterial effect of curcumin and chitosan-citric in films and potential application of films in realizing the rapid bacteriostatic effect during meat preservation was verified.…”