Functionality, physicochemical properties, and applications of chitosan/nano-hydroxyapatite-tea polyphenol films

Abstract

An active chitosan (CS) film containing a nano-hydroxyapatite-tea polyphenol (HAP-TP) complex was designed and prepared. The effects of HAP-TP loading on the structural and physicochemical properties of the CS-based film were evaluated. The mechanical and thermal properties of the film were significantly improved by the resulting intermolecular interactions and formation of hydrogen bonds between HAP-TP and CS, which reduced the water vapor and oxygen permeabilities of the film by 29.78 and 35.59 %, respectively. The CS-HAP-TP film exhibited excellent slow-release behavior and antioxidant activity, with a cumulative release rate at 700 h 6.79 % lower than that of CS-TP films. The CS-HAP-TP film significantly inhibited the deterioration of semi-dried golden pompano, and thus helped to retain the taste of umami and sweet amino acids in fish samples, while reducing off-flavor generation. The film therefore shows considerable potential as an active packaging material for the preservation of semi-dried fish products.

Keywords: Antioxidant activity; Chitosan-nano hydroxyapatite-tea polyphenol (CS-HAP-TP) films; Flavor; Physicochemical properties; Preservation; Sustained-release performance.

Fig. 1

Surface and cross-sectional SEM images of CS (A), CS-0.1 %HAP (B), CS-0.2 %TP (C), CS-0.1 %HAP-0.2 %TP (D), CS-0.1 %HAP-0.4 %TP (E) films.

Fig. 2

Fourier transform infrared (FTIR) spectra (A), differential scanning calorimetry (DSC) (B), thermogravimetric analysis (TGA) (C) and derivative thermogravimetric (DTG) analysis (D) of films.

Fig. 3

Properties of CS-HAP-TP flms: Tensile strength (TS) (A), elongation at break (EB) (B), water vapor permeation (WVP) (C), oxygen permeation (OP) (D), cumulative release rate of TP in food simulants (E), and scavenging of free radicals by DPPH (F) and ABTS (G). The different lower-case letters indicate statistically significant differences between different samples (P < 0.05).

Fig. 4

Total viable count (TVC) (A), total volatile base nitrogen (TVB-N) (B), thiobarbituric acid reactive substances (TBARS) (C), protein carbonyls (D), total sulfhydryl groups (E), and pH (F) of semi-dried golden pompano in the control and coated groups during storage. The different lowercase letters indicate statistically significant differences between different samples (P < 0.05).

Fig. 5

Cluster analysis plot (A) and species variation (B) of FAA during ambient storage of semi-dried golden pomfret in control and wrapped groups. UAA: umami amino acid, SAA: sweet amino acid, BAA: bitter amino acid, TFAA: total free amino acid.

Fig. 6

Thermograms (A), PCA (B) and PLS-DA (C), VIP score (D) and categorical bar graphs (E) of volatile organic compounds (VOCs) of semi-dried golden pompano fish in control and wrapped groups during storage. A: The color of each square in different rows indicate the relative concentration of VOCs in different samples. Red squares indicate higher levels of VOC, whereas blue squares indicate lower levels of VOC. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)

Fig. 6

Thermograms (A), PCA (B) and PLS-DA (C), VIP score (D) and categorical bar graphs (E) of volatile organic compounds (VOCs) of semi-dried golden pompano fish in control and wrapped groups during storage. A: The color of each square in different rows indicate the relative concentration of VOCs in different samples. Red squares indicate higher levels of VOC, whereas blue squares indicate lower levels of VOC. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)