Anjaly Shankar M; Rachna Sehrawat; Sunil Pareek; Prabhat K Nema
Abstract
Mushrooms are characterized as the fruiting bodies of fungi and are fruitful source of high-quality protein and vitamins with low calories. Among the three most cultivated species, the oyster mushroom stands with limited shelf life (2-3 days at refrigerated conditions). Elevated quotients of browning ...
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Mushrooms are characterized as the fruiting bodies of fungi and are fruitful source of high-quality protein and vitamins with low calories. Among the three most cultivated species, the oyster mushroom stands with limited shelf life (2-3 days at refrigerated conditions). Elevated quotients of browning reaction and restricted shelf life obliges the preservation of species as a matter of concern. A suitable pre-treatment along with the drying method is very important to retain the bioactive compounds of oyster mushroom. Pre-treatment optimization prior to oyster mushroom drying was carried out in two steps which involved individual and combined effects of blanching (70 to 90 oC) and chemical treatments. Thereafter, it was dried in a recently developed multi-mode novel drying unit under hot air and vacuum drying (50-70oC) conditions. Pre-treatment with citric acid and blanching at 80 oC for 2 min resulted in the lowest residual activity of polyphenol oxidase. Retention of phenolics, flavonoids, ascorbic acid and antioxidant compounds were higher in the samples dried using vacuum drying. Increase in temperature from 50 to 70 oC significantly decreased the bioactive compounds and colour of vacuum dried samples. In samples dried using hot air-drying, the higher retention of bioactive compounds and colour was obtained at 60 oC as compared to 70 oC and 50 oC. Page model was found to be the best fitted model among the different models studied. Analysis inferred the usefulness of optimised pre-treatment and vacuum drying technique at low temperature for drying of oyster mushrooms.Abbreviations: AA, Ascorbic acid; BI, Browning index CA, Citric acid; FRAP, Ferric reducing antioxidant power; KMS, Potassium metabisulphite; MR, Moisture ratio; PPO, Polyphenol oxidase; RR, Rehydration ratio; RSA, Radical scavenging activity; TFC, Total flavonoid content; TPC, Total phenol content
Md. Saidee Rahman; Md. Kamrul Hassan; Fakhar Uddin Talukder; Md. Sohanur Rahman
Abstract
A large amount of oyster mushrooms is wasted every year due to post-harvest losses/decays. An experiment was conducted to observe the effect of low temperature to extend shelf life and nutritional quality of oyster mushroom. The experiment consisted of two treatments including: mushrooms stored at ambient ...
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A large amount of oyster mushrooms is wasted every year due to post-harvest losses/decays. An experiment was conducted to observe the effect of low temperature to extend shelf life and nutritional quality of oyster mushroom. The experiment consisted of two treatments including: mushrooms stored at ambient (25 °C) temperature or stored at 3 °C temperature. The experiment was laid out in a Completely Randomized Design (CRD) with three replications. Parameters investigated were color, firmness, freshness, appearance, flavor, texture, moisture and dry matter contents, weight loss, protein content, disease incidence, disease severity and shelf life. Highest moisture contents (85.3%) and shelf life (11.92 days) were recorded in mushrooms exposed to low temperature, while the highestdry matter content (35.25%), weight loss (15.28%), protein content(24.64%) were detected in mushrooms exposed to ambient temperature and the lowest moisture content (64.75%), shelf life (3.33%) were observed in mushrooms exposed to ambient temperature. Lowest dry matter content (14.97%) and weight loss (4%) were recorded in low temperature-exposed mushrooms. At 3 °C, mushrooms had the best quality especially in relation to weight loss, disease incidence and severity, color, firmness, freshness, appearance, flavor, texture, and dry matter content compared to those exposed to ambient temperature. Storage at 3 °C ultimately resulted in prolonged shelf life.