Application of polyvinyl alcohol bionic films loaded with grape seed extract for postharvest preservation of Agaricus bisporus
Description
This study aimed to explore the loading of grape seed extract (GSE) into polyvinyl alcohol (PVA) using lotus leaf-like bionic structure for film engineering design. Through the casting and template method, a bionic composite film was fabricated and applied to the postharvest storage of Agaricus bisporus. Notably, the PVA film containing 40% GSE (BPG-40) showed good mechanical properties, with an elongation at break of 54.80%. Its antioxidant activity (64.18%) was significantly higher than that of the control film (3.44%), and it also demonstrated excellent antibacterial properties against Staphylococcus aureus and Escherichia coli. Meanwhile, cytotoxicity experiments demonstrated that the composite film exhibited no toxic side effects and possessed excellent biocompatibility, making it suitable for safe application in food storage applications. An experiment was conducted to evaluate the effects of the bionic composite film on Agaricus bisporus over a 12 days storage period at 4 ℃. The results indicated that the weight loss rate decreased from 6.62% in the control group to 2.05%, and the respiration rate declined from 355 mg/kg·h to 285 mg/kg·h of CO2. The retention rate of total phenolic content reached 0.72%, while polyphenol oxidase activity was merely 11.2 U/g, and malondialdehyde content was only 6 mmol/g. Therefore, the bionic composite film, characterized by good mechanical strength, antimicrobial and antioxidant properties, can effectively extend the shelf life of Agaricus bisporus and may serve as a potential material in the fields of food preservation and sustainable agriculture.
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Steps to reproduce
GSE (95% procyanidins) was purchased from Shandong Jinsheng Biotechnology Co., Ltd (Binzhou, China). PVA (Mw 20,000–150,000, 99% hydrolyzed) and polydimethylsiloxane (PDMS) were obtained from Dow Corning (USA). 1,1-diphenyl-2-benzhydrazine (DPPH) and 2,2-azino-4-(3-ethylbenzothiazol-6-sulfonic acid) disodium salt (ABTS) were purchased from Sigma-Aldrich (St. Louis, USA). Glycerol, phosphate buffer, potassium ferricyanide, anhydrous calcium chloride, trichloroacetic acid, potassium nitrate, ferric chloride, ethanol, nutrient agar, yeast extract, and peptone were obtained from Sinopharm Chemical Reagents Co., Ltd. (Shanghai, China). Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were provided by the Food Science and Engineering Laboratory of Jilin Agricultural University (Changchun, China). Agaricus bisporus was obtained from Walmart Supermarket in Changchun, China. GSE were dissolved in 100 mL of distilled water to make 10%, 20%, 30%, and 40% aqueous GSE solutions. A 5% PVA solution was prepared separately, and then the GSE and PVA solutions were mixed in a 1:1 ratio. To prepare the composite film solutions, 4% glycerol was added, and the mixture was magnetically stirred at 500 rpm for 1 h and then left to stand for 30 min. PDMS and its curing agent were mixed at a 10:1 ratio, magnetically stirred at 500 rpm for 2 h, and stabilized at 25 ℃ and 75% RH. The PDMS solution was coated on lotus leaf samples and dried at 110 ℃ for 1.5 h to form lotus leaf antistructured PDMS films. The composite film solution was coated on the PDMS film and dried at 80 ℃ for 6 h. The coated films were incubated in a constant temperature and humidity chamber at 25 ℃ and 75% RH for 24 h to get bionic films with leaf - like microstructure. The pure PVA film was used as the control. The bionic films with 0%, 10%, 20%, 30%, and 40% GSE were named BPG - 0, BPG - 10, BPG - 20, BPG - 30, and BPG - 40 respectively. Summary of Experiments and Instruments The experiments conducted mainly include the preparation of modified nanoparticles and composite antibacterial films, tests of film physical-mechanical properties, structural characterization, antioxidant and antibacterial properties, application in Agaricus bisporus postharvest preservation, cytotoxicity evaluation, and statistical analysis; the used instruments and equipment include spiral micrometer, colorimeter, UV spectrophotometer, electronic universal testing machine, SEM, FTIR, XRD, texture analyzer, centrifuge, ultrasonic cleaner, and relevant software (SPSS 26.0, Origin 2019), etc., for corresponding experimental operations.
Institutions
- Jilin Agricultural UniversityJilin, Changchun