Efficacy of Two Stabilizers in Nanoemulsions with Whey Proteins and Thyme Essential Oil as Edible Coatings for Zucchini

Abstract

Edible coatings are important for horticulture crops preservation and reducing food waste. Application of edible coatings followed by low-temperature storage prolongs the storability, preserves quality, and decreases the overall postharvest losses. This study evaluated the efficacy of two nanoemulsions formulae containing thyme essential oil and whey proteins as coatings for zucchini, with the purpose of extending their shelf-life. The nanoemulsions were rheologically evaluated and the formula with guar and arabic gum mix stabilizer (S) showed a better capacity to restructure after strain compared to the formulae with Tween 20 (T). The S coating material had a better capacity to integrate nanoparticles compared to T. However, when applied on zucchini, T coating was more effective in reducing weight loss showing 16% weight loss compared to 21% in S, after 42 days. At the end of storage at 10 °C, the T-coated zucchini had better firmness (p < 0.05) compared with S and both coatings were superior to control (p < 0.05). POD (peroxidase) activity was high in peel at the end of storage when also CAT (catalase) showed a sudden increase. On the 42nd day of storage, the highest enzymes activity (CAT, POD, and APX (ascorbate peroxidase)) was present in the S-coated zucchini peel. The most abundant volatile in T coating was α-pinene and 4-carene in S. Sensory analysis showed that T coating delayed the appearance of senescence while S exhibited surface cracks.

Monitoring the metabolite content of seasoned zucchinis during storage by NMR-based metabolomics

“…Concerning zucchinis, some studies focus on the possibility of extending their SL improving the conservation with different approaches. For example, the effect of different coatings on the quality of fresh zucchini during storage was investigated by evaluating physicochemical, visual [ 17 ] and sensorial properties [ 18 ]. The effects of individually shrink wrapping zucchini fruits on different quality parameters, namely cold tolerance, chilling injury, the loss of weight and firmness during storage at 4 °C, were also investigated [ 19 ] as well as the effects of other different treatments on fresh zucchini.…”

Development, RSM-based modeling, and process optimization of an ultrasonic coating system for extending the storage life of fresh fruits

“…In addition, GA has a low viscosity with high emulsification properties and strong stability, which can be used as an excellent film-forming material in food and non-food applications, e.g., bakery, beverages, fruits and vegetables, pharmaceuticals, and cosmetics (Kawhena et al, 2021;Taher et al, 2022). The effects of GA as an edible coating on the quality and shelf life of tomato (Ali et al, 2013), summer squash (Bleoanca et al, 2022), plum (Fawole et al, 2020), pomegranate (Kawhena et al, 2021), kaki (Saleem et al, 2023), peach (Taher et al, 2022), apple (Soppelsa et al, 2023), acid lime (Beheiry et al, 2023), strawberries (De Bruno et al, 2023), guava (El-Gioushy et al, 2022), banana (Maqbool et al, 2011), and papaya (Maqbool et al, 2011) have been investigated. The findings of the previous studies revealed that coating with GA delayed the ripening, decreased weight loss, reduced shrivel, postponed microbial spoilage, preserved the antioxidants, lowered browning and chilling damage, and prolonged the shelf life of fruits during storage.…”

Controlled Release of β-CD-Encapsulated Thyme Essential Oil from Whey Protein Edible Packaging

“…However, the EOs' high volatility, oxidizability, and thermosensitivity call for alternative protection techniques to counteract these negative traits. Several techniques are available for EO protection that are already used for active packaging, like their inclusion in composite materials (e.g., zeolite-thymol antimicrobial composites [13]); nanoemulsion formation (e.g., EF/TEO nanoemulsion used for zucchini active coating [14]); thymol nanoemulsion included in gelatin films [15] or encapsulation (e.g., edible coating with encapsulated TEO in liposomal chitosan applied to cheese [16]); and antimicrobial packaging with coriander EO encapsulated in cyclodextrin nano-sponges [17].…”