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Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Food & Machinery is the property of Food & Machinery Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Infrared blanching is a new pretreatment method for fruits and vegetables apple slices drying. However, the influence of the air medium properties on the infrared blanching is not clear, which is not conducive to developing the infrared blanching technology. In order to reveal the mechanism of the heat and mass transfer of infrared blanching pretreatment of apple slices and that effects on the drying process, the air medium humidity control technology was used in infrared blanching of apple slices in this paper. Numerical simulation was used to analyze the law of heat and mass transfer during infrared blanching of apple slices under different air relative humidity. The convection heat and mass transfer between air and material was obtained by Newton’s law of cooling, and the radiation heat transfer between infrared radiation source and material was solved by Stefan-Boltzmann’s law. According to Fick’s diffusion law and Fourier’s heat conduction law, the moisture diffusion and heat transfer in apple slice were calculated. The effect of infrared blanching under medium humidity control on drying efficiency and the color of products were studied by combining blanching and drying experiments. The results showed that the heat and mass transfer of infrared blanching for apple slices could be described by the mathematical model, which based on the heat transfer of infrared radiation and air convection, and considering moisture evaporation and vapor condensation. The model fitted well with the apple slice moisture and temperature data with average relative errors of 0.54% and 0.39%, respectively. The heat and mass transfer during infrared blanching involved the interaction of infrared radiation source, air medium and apple slice. At constant 120℃ of infrared heating temperature, the relative humidity of medium had effect on the heat and mass transfer during infrared blanching, drying rate after blanching, and product quality. Under the condition of low humidity (1% relative humidity), the water vapor partial pressure of the air medium was lower than that of the material surface. The moisture in material was transferred from the surface of the material to the air medium via diffusion, and the heat consumption of water evaporation accounted for 40% of the total absorbed heat of material, resulted in slow heating rate of material. At the constant temperature, the higher relative humidity, the more water vapor content in the equal amount of dry air. Increasing the relative humidity of the medium to 50% could effectively restrain the water evaporation of the apple slice that could greatly improve the heating rate of material at the initial stage of blanching. In 50% relative humidity, The center temperature of the material increased to 86.8℃ after blanching for 120 s. The drying rate and color quality of the apple chips could be improved by infrared blanching under high air relative humidity. Compared with 1% relative humidity, the pre-drying time of the apple slice was shortened by 8.3% under 50%IRB, and color difference and browning index of apple slice were reduced by 55.6% and 37.4%, respectively. The results provided a new idea for the development of infrared blanching pretreatment technology of fruits and vegetables to achieve high quality and efficient drying. [ABSTRACT FROM AUTHOR]

Heavy moisture content in the Huang-Huai Plain of China has posed great difficulty in the storage of maize ear, particularly easy to mildew. Scientific storage of fresh maize free from drying has become a high demand to reduce postharvest loss in the actual production of maize in the current cooperative society (co-op). In this study, a feasible storage warehouse with mechanical ventilation was developed for the storage of maize ear. A field test was also conducted. Precipitation with a strong wind at ambient temperature was utilized to specially design the air channel of Positive Pressure Ventilation (PPV), Negative Pressure Ventilation (NPV), and natural ventilation (NV) in a storage warehouse. A blowing machine and an Induced Draft (ID) fan ran alternately to achieve the air exchange in a storage warehouse. Some sensors were utilized to monitor the temperature and humidity of the storage warehouse in real time. A PLC control system was selected to match the alternate work of air exchange and regain consciousness, further to keep dry and quality on a large quantity of fresh corncob. In the niblet (kernel of corn), the moisture, fatty acid, and volume weight were measured to explore the change of mildew and quality, together with the moisture of corncob, and then to evaluate the storage character and loss, finally to establish predicted models during the storage. The test results showed that this storage warehouse with mechanical ventilation and temperature control can implement for 80-day dry storage of maize niblet. The parameters presented suitable for storage, where the moisture content was lower than the standard safe value, with maize fatty acid of 39.9 mg/100g, volume weight of 740g/L, mildew rate of 0.6%, broken rate of 0.4%, impurity rate of 0.07%, normal color and taste. The storage warehouses demonstrated the stable performance of waterproof, mildew resistant, and pest-proof, thereby reducing the postharvest loss and saving energy for the better quality of stored maize. The price was 0.2-0.25 Yuan/500g higher than that in the harvest season. As such, the farmers can keep maize in storage for a better price to sell. [ABSTRACT FROM AUTHOR]