Study of UV-C treatments on postharvest life of blueberries 'O'Neal' and correlation between structure and quality parameters

Protecting anthocyanins of postharvest blueberries through konjac glucomannan/low-acyl gellan gum coatings contained thymol microcapsule during low-temperature storage

In order to protect the anthocyanins in blueberries during low-temperature storage, TMs/KGM/LAG (TKL) coatings were developed by composite thymol/β-cyclodextrin (β-CD) microcapsules (TMs), konjac glucomannan (KGM), and low acyl gellan gum (LAG). The results showed that the TMs prolonged the release of thymol for at least 30 d. The TKL was effective in maintaining the color of blueberry skin by regulating the activities of key enzymes for anthocyanin synthesis and degradation. Among the different treatment groups, TKL60 (thymol concentration of 60 mg/L) was the most effective in protecting anthocyanin. At 42 d of storage, the TKL60 group showed the highest anthocyanin levels of malvidin-3-O-galactoside (718.38 μg/g), delphinidin-3-O-galactoside (343.75 μg/g) and cyanidin-3-O-galactoside (40.67 μg/g). In addition, TKL60 treatment still showed good maintain the qualities of blueberries (weight loss, decay, hardness and TSS). Thus, this study provides a new approach to protect anthocyanin in blueberries after harvest during low-temperature storage.

Composition, metabolism and postharvest function and regulation of fruit cuticle: A review

The cuticle of plants, a hydrophobic membrane that covers their aerial organs, is crucial to their ability to withstand biotic and abiotic stressors. Fruit is the reproductive organ of plants, and an important dietary source that can offer a variety of nutrients for the human body, and fruit cuticle performs a crucial protective role in fruit development and postharvest quality. This review discusses the universality and diversity of the fruit cuticle composition, and systematically summarizes the metabolic process of fruit cuticle, including the biosynthesis, transport and regulatory factors (including transcription factors, phytohormones and environmental elements) of fruit cuticle. Additionally, we emphasize the postharvest functions and postharvest regulatory technologies of fruit cuticle, and propose future research directions for fruit cuticle.

The Attenuation of Microbial Reduction in Blueberry Fruit Following UV-LED Treatment

Ultraviolet-C (UV-C) irradiation is a well-recognized technology for improving blueberry postharvest quality, and previous literature indicates that it has the potential for dual-use as an antimicrobial intervention for this industry. However, the practicality and feasibility of deploying this technology in fresh blueberry fruit are significantly hindered by the shadowing effect occurring at the blossom-end scar of the fruit. The purpose of this study was to determine if treating the blueberry fruit within a chamber fitted with UV-Light Emitting Diodes (LEDs) emitting a peak UV-C at 275 nm could minimize this shadowing and result in improved treatment efficacy. Ten blueberry fruits were dip-inoculated with E. coli at a concentration of 10⁵ CFU/mL and irradiated within the system at doses of 0, 1.617, 3.234, 9.702, and 16.17 mJ/cm² (0, 30, 60, 180, and 300 s). Statistical analysis was performed to characterize the extent of microbial survival as well as the UV-C inactivation kinetics. A maximum of 0.91-0.95 log reduction was observed, which attenuated after 60 s of treatment. The microbial inactivation and survival were thus modeled using the Geeraerd-tail model in Microsoft Excel with the GInaFIt add-in (RMSE = 0.2862). Temperatures fluctuated between 23 ± 0.5°C and 39.5°C ± 0.5°C during treatment but did not statistically impact the treatment efficacy (P = 0.0823). The data indicate that the design of a UV-LED system may improve the antimicrobial efficacy of UV-C technology for the surface decontamination of irregularly shaped fruits, and that further optimization could facilitate its use in the industry.

The Effect of UV-C Irradiation on the Mechanical and Physiological Properties of Potato Tuber and Different Products

Amongst the surface treatment technologies to emerge in the last few decades, UV-C radiation surface treatment is widely used in food process industries for the purpose of shelf life elongation, bacterial inactivation, and stimulation. However, the short wave application is highly dose-dependent and induces different properties of the product during exposure. Mechanical properties of the agricultural products and their derivatives represent the key indicator of acceptability by the end-user. This paper surveys the recent findings of the influence of UV-C on the stress response and physiological change concerning the mechanical and textural properties of miscellaneous agricultural products with a specific focus on a potato tuber. This paper also reviewed the hormetic effect of UV-C triggered at a different classification of doses studied so far on the amount of phenolic content, antioxidants, and other chemicals responsible for the stimulation process. The combined technologies with UV-C for product quality improvement are also highlighted. The review work draws the current challenges as well as future perspectives. Moreover, a way forward in the key areas of improvement of UV-C treatment technologies is suggested that can induce a favorable stress, enabling the product to achieve self-defense mechanisms against wound, impact, and mechanical damage.