Tianjia Jiang

Browning inhibition and quality preservation of button mushroom (Agaricus bisporus) by essential oils fumigation treatment

The effect of essential oil fumigation treatment on browning and postharvest quality of button mushrooms (Agaricus bisporus) was evaluated upon 16 days cold storage. Button mushrooms were fumigated with essential oils, including clove, cinnamaldehyde, and thyme. Changes in the browning index (BI), weight loss, firmness, percentage of open caps, total phenolics, ascorbic acid, microbial activity and activities of polyphenol oxidase (PPO), phenylalanine ammonia lyase (PAL), and peroxidase (POD) were measured. The results indicated that all essential oils could inhibit the senescence of mushrooms, and the most effective compound was cinnamaldehyde. Fumigation treatment with 5 μl l⁻¹ cinnamaldehyde decreased BI, delayed cap opening, reduced microorganism counts, promoted the accumulation of phenolics and ascorbic acid. In addition, 5 μl l⁻¹ cinnamaldehyde fumigation treatment inhibited the activities of PPO and POD, and increased PAL activity during the storage period. Thus, postharvest essential oil fumigation treatment has positive effects on improving the quality of button mushrooms.

Effects of tea polyphenol coating combined with ozone water washing on the storage quality of black sea bream (Sparus macrocephalus)

The present research evaluated the effects of tea polyphenol (TP) combined with ozone water (O(3)) on the quality of black sea bream (Sparus macrocephalus) over a period of 15 days storage at 4°C. A solution of TP (0.2%, w/v) was used to coat the fish after washing with ozone water (1mg/L). Fish physicochemical (pH, K value, peroxide value, thiobarbituric acid, total volatile basic nitrogen, trimethylamine, texture, and colour), sensory, and bacteriological characteristics were all analysed. TP+O(3) treatment effectively reduced nucleotide breakdown, lipid oxidation, protein decomposition, and microbial growth, and maintained better characteristics of texture, colour, and sensory compared with the control. The efficiency of TP+O(3) treatment was also better than that of TP treatment or O(3) treatment alone. Therefore, tea polyphenol coating combined with ozone water prewashing may be a promising method of maintaining the storage quality of black sea bream and of extending fish post-mortem shelf-life during 4°C storage.

Fumigation with essential oils improves sensory quality and enhanced antioxidant ability of shiitake mushroom (Lentinus edodes).

Several naturally occurring essential oils were evaluated for their effectiveness in maintaining sensory quality and increasing antioxidant levels and activities in shiitake (Lentinus edodes) mushrooms. Freshly harvested mushrooms were fumigated with 5 μl l(-)(1) clove, cinnamaldehyde and thyme oils at 10 °C for 1.5h and the antioxidant activities determined using assays of H2O2 content, O2(-) production rate, DPPH, and ABTS radical scavenging activity. The results showed that the antioxidant activities of the mushrooms fumigated with cinnamaldehyde were significantly increased when compared to the controls. Moreover, cinnamaldehyde fumigation significantly delayed losses of phenolic compounds and enhanced flavonoid content. The essential oil fumigation treatment also increased the antioxidant enzyme activities of CAT, SOD, APX and GR throughout the storage periods. All the fumigation treatments were effective in retarding mushroom sensory deterioration. These results indicate that postharvest application of essential oil fumigation can extend the shelf life and enhance the antioxidant capacity of shiitake mushrooms.

Effect of Chitosan Coating Enriched with Thyme Oil on Postharvest Quality and Shelf Life of Shiitake Mushroom (Lentinus edodes)

The effect of chitosan-oil coating on the postharvest quality and shelf life of shiitake (Lentinus edodes) mushrooms stored at 4 ± 1 °C for 16 days was investigated. Mushroom weight loss, firmness, total phenolics, ascorbic acid, malondialdehyde (MDA), electrolyte leakage rate, and microbial and sensory quality were measured. The results indicate that treatment with chitosan-oil coating maintained tissue firmness, inhibited increase of respiration rate, and reduced microorganism counts, such as yeasts and molds and pseudomonad, compared to control treatment. The efficiency was better than that of thyme oil treatment or chitosan coating. Furthermore, shiitake mushrooms treated with chitosan-oil coating also exhibited significantly higher levels of total phenolics, flavonoids, as well as individual phenolic compounds than control. Sensory evaluation proved the efficacy of chitosan-oil coating by maintaining the overall quality of shiitake mushroom during the storage period. Our study suggests that chitosan-oil coating might be a promising candidate for maintaining shiitake mushroom quality and extending their postharvest life.

Physicochemical responses and microbial characteristics of shiitake mushroom (Lentinus edodes) to gum arabic coating enriched with natamycin during storage

Physicochemical responses and microbial characteristics of shiitake mushroom (Lentinus edodes) to gum arabic (GA) coating incorporating natamycin (NA) during storage were investigated. Mushroom weight loss, firmness, total soluble solids, total sugar, reducing sugar, ascorbic acid, and microbial and sensory quality were measured. Mushroom coated with gum arabic+natamycin (GANA) maintained tissue firmness and showed reduction in microbial counts from yeasts and moulds compared with the control. In addition, GANA coating also delayed changes in the soluble solids concentration, total sugar and ascorbic acid. Sensory evaluation proved the efficacy of GANA coating by maintaining the overall quality of shiitake mushroom during the storage period. The efficiency was better than that of GA or NA treatment alone. Our study suggests that GANA has the potential to improve the quality of shiitake mushroom and extend its shelf-life up to 16d.

Effect of alginate/nano-Ag coating on microbial and physicochemical characteristics of shiitake mushroom (Lentinus edodes) during cold storage.

The effect of a novel alginate/nano-Ag coating material on the preservation quality of shiitake mushroom (Lentinus edodes) during 4±1°C storage was investigated. The results showed that the alginate/nano-Ag coating had quite a beneficial effect on the physicochemical and sensory quality, compared to the control treatment. After a 16-day storage, mushroom weight loss, softening, and browning of the alginate/nano-Ag coating were significantly inhibited. The lower microbial counts, including mesophilic, psychrophilic, pseudomonad, and yeasts and moulds, in treated mushrooms during storage should be attributed to the alginate/nano-Ag coating. Meanwhile, the contents of the reducing sugar, total sugar, total soluble solids and electrolyte leakage rate were increased to 3.9mg/g, 11.2mg/g, 5.1% and 16.5% for the alginate/nano-Ag coating and 3.7mg/g, 8.3mg/g, 6.3% and 31.7% for the control treatment. Therefore, the alginate/nano-Ag coating could be applied for preservation of the shiitake mushroom to expand its shelf life and improve its preservation quality.

Pre-harvest application of oxalic acid increases quality and resistance to Penicillium expansum in kiwifruit during postharvest storage

Kiwifruit (Actinidia deliciosa cv. Bruno) fruits were sprayed with 5mM oxalic acid (OA) at 130, 137, and 144 days after full blossom, and then harvested at commercial maturity [soluble solid content (SSC) around 10.0%] and stored at room temperature (20 ± 1 °C). Pre-harvest application of OA led to fruit with higher ascorbic acid content at harvest, slowed the decreases in fruit firmness and ascorbic acid content and increase in SSC during storage, and also decreased the natural disease incidence, lesion diameter, and patulin accumulation in fruit inoculated with Penicillium expansum, indicating that the OA treatment increased quality and induced disease resistance in kiwifruit. It was suggested that the increase in activities of defense-related enzymes and in levels of substances related to disease resistance might collectively contribute to resistance in kiwifruit against fungi such as P. expansum in storage.