Mechanical damage and microbial infestation were critical issues during strawberry transportation. This study prepared a modified polyvinyl formal (PVFM) vibration-damping material and investigated its application in strawberry transportation. This modified PVFM was primarily composed of polyvinyl alcohol, starch, formaldehyde, and allyl isothiocyanate. Our results showed that the modified PVFM had good vibration-damping and antifungal properties with 0.137 g/m 3 of density, a water absorption ratio value of 6.24, 278 Pa of tensile strength, 3.86 Pa of elastic modulus, a buffer coefficient of 0.318, and antifungal rates of 68.8% and 80.6% against Bacillus anthracis and Botrytis cinerea , respectively. Moreover, this modified PVFM could enhance the storage life of strawberry by improving PAL activity from 376 to 3,125 U/g, inhibiting POD activity with a maximum value of 3.1 U/g, and decreasing CAT activity from 324 to 35 U/g. The modified PVFM presented a good vibration-damping capacity and the potential to extend strawberry shelf life. Practical applications Berry fruits were vulnerable to mechanical damage caused by vibration during transportation, resulting in quality deterioration, rot, and aging. In this study, modified polyvinyl formal (PVFM) was prepared and was of low density and displayed good mechanical, vibration-damping, and antifungal properties. The modified PVFM could improve the storage life of strawberry. Thus, the modified PVFM could have potential application in berry fruits transportation.
Two low-methoxy pectins (LMPs) were obtained by local electrochemical pH modification using an H-type double-layer water bath sealed electrochemical cell at the voltage of 180 V for 3 h. The weight-average molecular weight (Mw) of citrus peel pectin (CPP) prepared in the anodic part at room temperature (CPP-A 5/RT ) and in the cathodic part at 5 °C (CPP-C 5/RT ) were 346 kDa and 328 kDa, respectively, and the degrees of methylation (DM) were 36.8 % and 11.9 %. Moreover, the second-order kinetic model was most appropriate for the degradation processes, as free radicals were generated in the anodic part and β -elimination occurred in the cathodic part. Subsequently, CPP-A 5/RT and CPP-C 5/RT were utilized to fabricate food packaging film blending with polyvinyl alcohol (PVA), bcZnO (ZnO coupled with bentonite and colophony) nanorods , and Ca 2+ ions by casting method. Then the prepared films were studied for their ability to maintain the freshness of strawberries. The addition of Ca 2+ ions and bcZnO nanorods increased the thickness, water contact angle (WCA), and mechanical properties of the composite films, while decreased water vapor permeability (WVP). Therefore, the CPP-based films, supplemented with bcZnO nanorods and crosslinked with Ca 2+ ions by “egg-box” model, can serve as an antibacterial food packaging material for food preservation.
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