One-Step Synthesis of Poly(L-Lactic Acid)-Based Soft Films with Gas Permselectivity for White Mushrooms (Agaricus bisporus) Preservation

Effects of 60Coγ-irradiation combined with sodium dehydrogenate on post-harvest preservation and physiological indices of Volvariella volvacea

Volvariella volvacea is a mushroom known for its high palatability and nutritional value. However, it is susceptible to spoilage thus making it challenging to preserve and keep fresh after harvest, resulting in constraints in long-distance transportation and long-term storage. This study aimed to investigate the feasibility of using irradiation and sodium dehydrogenate (SD) as a preservative in the preservation process of V. volvacea. The effects of three treatments of 0.8 kGy 60Coγ irradiation (B), 0.04% SD (C), combined with 0.04% SD and 0.8 kGy 60Coγ irradiation (A) on the postharvest freshness of V. volvacea were investigated. The assessment indices for V. volvacea, including appearance, browning rate, weight loss, respiration rate, MDA content, antioxidant enzyme activities, vitamin C (Vc), and soluble protein content, were measured and compared. The three treatments were compared to determine the changes in storage time over 7 days post-harvest. The results demonstrated that the hardness of the fruiting body exhibited a significant increase of 81.19%, 97.96% and 168.81% in comparison to the control, B and C, respectively, following the application of the treatment A. Compared to the control group, the soluble protein content was significantly increased by 20.28%. Respiration intensity and browning rate were significantly lower in the control treatment, decreasing by 35.07% and 45.49% respectively. On the 6th day of storage, the activities of SOD and POD increased by 81.06% and 73.71%, respectively, compared to the control, which significantly delayed the senescence of the fruiting bodies. The Vc content was significantly increased by 50.27%, 133.90%, and 101.39% in treatment B, which received 0.8 kGy 60Coγ irradiation alone, compared to the control, treatment A, and treatment C, respectively. The treatment C alone significantly reduced respiratory intensity and MDA variables by 39.55% and 31.01%, respectively, compared to the control. The findings can provide theoretical references and technical support for extending the preservation period of V. volvacea after harvesting by using irradiation and sodium dehydrogenate as a preservative.

Preparation of hydroxypropyl methylcellulose/pueraria-based modified atmosphere film and its influence on delaying the senescent process of postharvest Agaricus bisporus

Based on the key factor of spontaneous modified atmosphere packaging (MAP)-gas permeability, a spontaneous MAP film was created for the preservation of Agaricus bisporus by delaying the senescence of white mushrooms. Compared with other mixed films, hydroxypropyl methylcellulose (HPMC)/pueraria (P)-2 showed better mechanical properties, barrier properties and thermal stability energy. Applying the HPMC/P-2 film for preserving white mushrooms can spontaneously adjust the internal gas environment. Moreover, the O2 concentration in the package remained stable at 1-2 %, and the CO2 concentration was between 8 % and 14 %. The film can effectively reduce the respiration rate of white mushrooms, inhibit enzymatic browning, maintain their good color and texture, and delay their aging. In conclusion, the HPMC/P-2 film can be used not only for fruit and vegetables preservation but also provide theoretical basis for sustainable food packaging.

Investigating the Respiratory and Energy Metabolism Mechanisms behind ε-Poly-L-lysine Chitosan Coating's Improved Preservation Effectiveness on Tremella fuciformis

Freshly harvested Tremella fuciformis contains high water content with an unprotected outer surface and exhibits high respiration rates, which renders it prone to moisture and nutrient loss, leading to decay during storage. Our research utilized ε-poly-L-lysine (ε-PL) and chitosan as a composite coating preservative on fresh T. fuciformis. The findings revealed that the ε-PL + chitosan composite coating preservative effectively delayed the development of diseases and reduced weight loss during storage compared to the control group. Furthermore, this treatment significantly decreased the respiration rate of T. fuciformis and the activity of respiratory metabolism-related enzymes, such as alternative oxidase (AOX), cytochrome c oxidase (CCO), succinic dehydrogenase (SDH), 6-phosphogluconate dehydrogenase, and glucose-6-phosphate dehydrogenase (6-PGDH and G-6-PDH). Additionally, the composite coating preservative also delayed the depletion of ATP and ADP and maintained higher levels of the energy charge while preserving low levels of AMP. It also sustained heightened activities of Mg2+-ATPase, Ca2+-ATPase, and H+-ATPase enzymes. These results demonstrate that utilizing the ε-PL + chitosan composite coating preservative can serve as a sufficiently safe and efficient method for prolonging the shelf life of post-harvest fresh T. fuciformis.

Circular Bioeconomy: Novel Processes and Materials for Food Preservation

Food preservation is a set of procedures and resources aimed at blocking the action of external and internal agents that may alter the original characteristics of food [...].

Effect of Controlled Atmosphere Packaging on the Physiology and Quality of Fresh-Cut Dictyophora rubrovolvata

Dictyophora rubrovolvata is a typical edible fungus of Guizhou Province and is very popular due to its unique taste and texture. In this study, the effect of a controlled atmosphere (CA) on fresh-cut D. rubrovolvata shelf life was investigated. Firstly, this study addresses the influence of different O₂ concentrations (5%, 20%, 35%, 50%, 65%, 80%, or 95%) with N₂ balance on fresh-cut D. rubrovolvata quality while stored at 4 ± 1 °C for 7 d. Then, on the basis of the determined O₂ concentration (5%), CO₂ (0%, 5%, 10%, 15%, or 20%) was involved and stored for 8 d at 4 ± 1 °C. Evaluations of physiology parameters, texture, browning degree, nutritional, umami, volatile components, and total colony numbers were determined in fresh-cut D. rubrovolvata. From the results of water migration, the sample of 5% O₂/5% CO₂/90% N₂ was closer to 0 d than other groups at 8 days. Meanwhile, the polyphenol oxidase (2.26 ± 0.07 U/(g·min)), and catalase activity (4.66 ± 0.08 U/(g·min·FW)) were superior to the samples of other treatment groups on the eighth day (3.04 ± 0.06 to 3.84 ± 0.10 U/(g·min), 4.02 ± 0.07 to 4.07 ± 0.07 U/(g·min·FW)). Therefore, we found that a gas environment with 5% O₂/5% CO₂/90% N₂ could ensure the membrane integrity, oxidation, and prevent the browning of fresh-cut D. rubrovolvata, thus better maintaining the physiological parameters. Meanwhile, it also maintained the samples' texture, color, nutritional value, and umami taste. Furthermore, it inhibited the increase in total colony numbers. The volatile components were closer to the initial level compared with other groups. The results indicate that fresh-cut D. rubrovolvata could maintain its shelf life and quality when stored in 5% O₂/5% CO₂/90% N₂ at 4 ± 1 °C.