Hossein Meighani; Mohammad Sadat-Hosseini
Abstract
Indian jujubes are perishable fruits with a short storage life after harvest. In this study, Indian jujube fruits were stored at 5 °C and 90% RH for 30 days after treating the fruits with 1% chitosan (CHS), 1 mM putrescine (PUT), and a combination of 1% CHS and 1 mM PUT (CHS+ PUT). Physicochemical ...
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Indian jujubes are perishable fruits with a short storage life after harvest. In this study, Indian jujube fruits were stored at 5 °C and 90% RH for 30 days after treating the fruits with 1% chitosan (CHS), 1 mM putrescine (PUT), and a combination of 1% CHS and 1 mM PUT (CHS+ PUT). Physicochemical characteristics and cell wall degrading enzymes were measured at 10-day intervals. The results indicated that the efficiency of the CHS+PUT was better than CHS or PUT as individual treatments. The CHS+PUT treatment substantially decreased weight loss, decay incidence, and malondialdehyde content in Indian jujube fruits. The CHS+PUT treatment minimized losses of bioactive compounds (ascorbic acid and phenols), total antioxidant activity, and titratable acidity. In addition, CHS+PUT treatment delayed fruit softening by suppressing polygalacturonase activity and pectin methylesterase enzymes. Soluble solids content significantly increased through storage time, but applying CHS and PUT individually or in combination inhibited this increase. These results confirmed that the 1% CHS and 1 mM PUT treatments maintained the postharvest quality of Indian jujube fruits in cold storage.
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
