Application of activated hybrid zein/inulin nanofibers for packaging offresh beef

Introduction: Food packaging has undergone significant changes to enhance food quality andtackle environmental issues. In light of the present emphasis on innovative and sustainabletechniques, developing a "green" packaging approach using renewable and biodegradable materialsis crucial to solve the food supply's disposal issues. Moreover, there is an increasing tendency touse biodegradable films and nanofibers (NFs) as active food packaging. The objective of the presentstudy was to examine the possibility of the hybrid zein/inulin NFs incorporated with CuOnanoparticles (NPs) and Foeniculum vulgare essential oil (FEO) for packaging fresh beef byanalyzing the physicochemical and microbiological properties of the beef as it is stored.Methods: After determining the optimal electrospun ratio (Z۹۰/IN۱۰) for ideal spinningcapabilities, CuONPs and FEO were introduced to the polymer blend solution at a ratio of ۰.۲۵ and۰.۵ % w/w of total biopolymer content. Moreover, the mixtures were stirred at room temperaturefor ۱۲ hours. Finally, electrospinning was implemented with the solution. The prepared NFs wereemployed to wrap the fresh beef samples. Additionally, the control beef sample was enclosed withina transparent, sterile polyethylene bag of similar dimensions. The beef samples were preserved at ۴°C for ۱۲ days. They were then analyzed at three-day intervals, specifically on days ۳, ۶, ۹ and ۱۲for the measurement of pH, thiobarbituric acid reactive substances (TBARS), and total bacterialcount (TBC).Results: Both beef samples illustrated an increasing trend in pH levels over the period of storage.During the preservation of the control sample, the pH value experienced an increase from ۵.۳ to ۸,reaching the highest pH level. The rising pH trend can be attributed to the accumulation of nitrogencompounds resulting from protein denaturation produced by microbial enzyme activity, as well asthe release of volatile basic substances due to microbial growth. However, beef samples wrappedwith nanofiber sample had meaningfully (p<۰.۰۵) limited increase of pH during the storage. Thisnanofiber has antibacterial properties, which inhibit the growth of bacteria and hence decrease theaccumulation of bacterial metabolites. The TBARS values in both beef samples exh ibited aprogressive increase with the duration of storage, which may be attributed to the development oflipid oxidation products. Nevertheless, this increasing trend was controlled by packaging beefsamples with NFs. Both the control and nanofiber-treated samples had initial TBARS values of ۰.۳۱mg MDA/۱۰۰g. From the ۹th day, the control group had significantly higher TBARS values thanthe nanofiber-packed group (P < ۰.۰۵). At the end of the storage period, the TBARS value of thebeef samples wrapped in NFs (۰.۶۸ mg MDA/۱۰۰g) was lower at ۱۲ days compared to the control(۰.۷۷ mg MDA/۱۰۰g) (P < ۰.۰۵). The findings demonstrated that the prepared NFs exhibited potentantibacterial and antioxidant properties, which effectively inhibited lipid oxidation in beef samples.Furthermore, the microorganism's growth in the beef samples exhibited a consistent increase as thestorage duration extended. The primary TBC values were ۲.۵ log CFU/g, suggesting that the beef۸۳۸samples exhibited satisfactory microbiological quality. The TBC value of the control groupexceeded the standard limit by the end of the storage period, reaching ۷.۴ log CFU/g, which wassignificantly (P < ۰.۰۵) higher than the TBC value of the wrapped beef sample by NFs (۵.۳ logCFU/g). Therefore, the treated sample remained within the prescribed limit and was consideredacceptable from a microbiological standpoint after being stored for ۱۲ days. This outcomeconfirmed the effectiveness of the developed nanofiber in inhibiting bacterial growth.Conclusion: The potential of the developed active NFs was confirmed for packaging fresh beef andthe changes of important parameters including pH, TBRAS, and TBC were controlled duringstorage time by packaging with these NFs. However, we recommended that the potential of thisactive packaging material and other similar NFs should be more studied for different foodstuffs.

کلیدواژه ها:

Green Packaging ، Active Packaging ، Electrospinning ، Encapsulation