| Blueberry is a kind of emerging fruit with edible value. They are very popular due to their healthmoting substances. But blueberry is perishable in room temperature because of the soft fruit flesh soft and the high temperature and rainy season at harvest time. Therefore it is necessary to develop strategies to increase their storage life. Blueberries "bluecrop" as test materials and the MAP storage of blueberries, respiration model are studied in this article. The studies can be for blueberry fresh-keeping provides theory basis. The research content and the results are as follows:1. The common cold storage, the unsealed packaging storage and MAP were designed at (0.5±0.5)℃storage temperature. The nutrition and physiological indexes for blueberries of the three storage ways were determined in storage period, and the storage effect of blueberries was studied. The results indicate that at (0.5±0.5)℃, MAP can keep the VC and titration acid content, restrain PPO and PG activity, so as to reduce the fruit browning and the original pectin decomposition, and make the fruit has high hardness. At the same time MAP can keep a high POD activity, which can clear away free radicals which blueberry metabolism produced, so the aging of blueberries was delayed and the blueberry fruit storage period was extend. Therefore, the storage effect of MAP cold storage is better than that of normal cold storage and unsealed packaging cold storage.2. It was studied the influence of the atmosphere concentration in MAP for the film thickness and film area and storage weight by a single factor experiment in this paper. The results showed that there are good linear relationships between the film thickness, film area and storage weight with the gas concentration in MAP has good linear relationship. When the film area and storage weight are fixed, CO2concentration gradually rise and O2concentration gradually decrease along with the increase of the thin film thickness. When the film thickness and storage weight are fixed, with the increase of film area, O2, CO2concentration down; When the film thickness and film area are fixed, in MAP O2concentration fall, CO2concentration go up along with the increase of storage weight.3. The three-element quadratic regression orthogonal experiment was designed in this paper. The good fruit rate, CO2and O2concentration in MAP were as test indicators. The three regression equations about the film thickness, film area and storage weight with the test indicators were obtained through the SPSS software. The polyethylene MAP specifications, O2and CO2concentration that are appropriate for blueberry storage were calculated by the method of extremum. The results showed that at (0.5±0.5)℃, the optimal specification for the blueberry storage is a MAP for the film thickness of33μm, film area of9.72×10-2m2, the storage of0.762Kg; And CO2and O2concentration is2.8%,15.4%respectively were got when the optimal specification of MAP for the storage of blueberries.4. The respiratory rate of blueberries was determined and characterized in airtight system at (25±0.5)℃and (0.5±0.5)℃.The results showed that low temperature can effectively restrain the blueberry respiration; In the course of the experiments, respiratory rate no obvious climacteric peak, so the respiratory type of blueberries which were used for experiment is the nonclimacteric. The respiratory models of blueberries in airtight system at (25±0.5)℃and (0.5±0.5)℃are obtained through Michaetis-Menten application and multiple linear regressions. This research has certain directive significance for the design of the MAP. |
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