Effects of grape seed extract on the properties of pullulan polysaccharide/xanthan gum active films for apple preservation.

Grape seed extract (GSE) was added to pullulan polysaccharide (PP)/xanthan gum (XG) as composite film (PP/XG/GSE or PXG). The observed composite morphology indicated their biocompatibility. Sample PXG100 (contain 100 mg/L GSE) demonstrated the best mechanical properties, with tensile strength of 16.62 ± 1.27 MPa, and the elongation at break of (22.60 ± 0.48)%. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging activity of PXG150 were the highest at (81.52 ± 1.57)% and (90.85 ± 1.54)%, respectively. PXG films also demonstrated inhibitory effects on Staphylococcus aureus, Escherichia coli, and Bacillus subtilis. The PXG films could also prolong the shelf life of fresh-cut apples because it could decrease the rate of weight loss and retain more vitamin C and total polyphenol even on the 5th day. The weight loss rate of PXG150 was decreased from (8.58 ± 0.6)% (control) to (4.15 ± 0.19)%. It was able to achieve vitamin C and total polyphenol retention rate of 91 % and 72 %, respectively, which was significantly higher that the control sample. Therefore, GSE had contributed in enhancing the antibacterial, antioxidant properties, mechanical strength, UV protection and water resistance in PXG composite films. This effectively extend the shelf life of fresh-cut apples, which it will be an excellent food packaging material.

Effects of Polygonatum cyrtonema extracts on the antioxidant ability, physical and structure properties of carboxymethyl cellulose-xanthan gum-flaxseed gum active packaging films.

A novel film composed of Polygonatum cyrtonema extracts (PCE), xanthan gum (XG), flaxseed gum (FG) and carboxymethyl cellulose (CMC) was prepared (XFCP). Addition of PCE has decreased the light transmittance, while enhanced the UV blocking performance, antioxidant activity, tensile strength and elongation at break of XFCP due to polysaccharides, polyphenols, and flavonoid in PCE. Structural analyses by FTIR and XRD indicated the hydrogen-bonding interaction between PCE, XG, FG and CMC. It was found that compared with the control sample, XFCP2.5% with the lowest WVTR was able to prolong the shelf life of mango. The overall quality of mango was also improved in terms of lower decay rate, weight loss rate, total soluble solid, and polyphenol oxidase, higher titratable acidity, Vc, and superoxide dismutase than control mango upon 8 days of storage. This effectively expanded the application of PCE into food packaging in addition to merely as Chinese traditional medicine herbs.

Development of xanthan gum/hydroxypropyl methyl cellulose composite films incorporating tea polyphenol and its application on fresh-cut green bell peppers preservation.

The aim of this work was to develop an edible packaging material with good performance that can be used for fresh-cut vegetables preservation. The xanthan (XG)-hydroxypropyl methylcellulose (HPMC)-tea polyphenols (TP) composite film (XHT) was prepared by adding TP to the composite film-forming solution of XG and HPMC. At optimum TP dosage of 6% (XHT6), the tensile strength and elongation at break were at the maximum. The antioxidant activity and antibacterial properties were also enhanced, demonstrated good inhibitory ability to Staphylococcus aureus. After 8 days, the amount of Vitamin C that was retained by XHT6 was 127.81% and 7.83% higher than unpackaged and XHT0, respectively. Additionally, the MDA content in green peppers were 39.16% and 78.87% higher than that of unpackaged and XHT0, respectively. Practical applications of XHT films in preserving fresh-cut bell peppers had also shown positive results, making it possible as potential food packaging.