Quality Changes Of Rice During Storage

As one of the important major crops in China, rice has a lot of processing performance, such as coarse grains processing, rice protein extraction, cooking process and so on. During storage, the each component which effected by rice storage environment, could lead to severe loss of nutrients of rice each, losing appearance quality,cooking and nature, resulting in a qualitative change in processing performance of rice each. In this paper, we select rice as the test material which come from Tianjin station, Du Li industry. By determining experiment, the optimal storage temperature of rice was defined. And we also studied the effect on rice quality at different packaging methods, such as modified atmosphere. The major rice storage environment and propose new methods of rice and other food industries were determined by studying the test. Detailed results and the main research contents are described as follows:1. The selection of the optimal storage temperatureUsing moisture content, fatty acid value, sugar, and other thermodynamic properties which were closely related to the quality of the rice storage as an important assessment indicators, supplemented after its storage physiological and biochemical indicators to determine the optimum storage temperature of rice. The results showed that there were some changes on the rice moisture content, fatty acid value and sugar at different storage temperature (1℃,5℃,15℃,25℃,35℃) When warranted on90d,Under1℃,5℃, the moisture content was an increase of0.7and0.4percentage points, but under15℃and25℃,there was a lower moisture content fell0.2and1.4percentage points. Stored at35℃,it’s reduced3.2percentage points. After75d. It can be concluded from the results that rice had lost its luster and the color yellow and exuded a more exciting smell and lost the rice aroma,It also could be determined that rice quality and appearance lost seriously eating quality. Also rice flour had high melting point when it pasting and require higher temperatures to achieve pasting temperature, however, there are severe deterioration of rice quality on high temperature. Compared with high temperature, low temperature (1℃、5℃) storage need high cost, and it’s not conducive to rice storage with high humidity environment. Therefore this chapter study only to75d under storage at35℃. After75d,rice has lost food value. However below15℃, it can be concluded that it can reduce the respiratory metabolism of rice, and a slow increase in the value of the fatty acids and reduce the increase of reducing sugars.2.The selection of the optimal storage modified atmosphere packagingThe modified atmosphere packaging contain the gas composition (100%CO2、100%N2 80%CO2+20%N2、50%CO2+50%N2and vacuum packaging) was studied in this chapter. The rice moisture content, fatty acid value and rice important sensory indicators:cooking quality which were related to rice quality were studied in this chapter. The result showed that compare with other packaging group, modified atmosphere packaging group could slow water loss, reduce the cooking quality and fatty acid oxidation,better maintain the quality of rice. Followed by vacuum packaging group, using vacuum packaging of its storage quality were slightly less than100%CO2group, but compared with other group, vacuum packaging group had better quality. Each operation had some differences because of human error, material and gas barrier and other reason. Through the study that we can find there are less difference between modified atmosphere packaging at100%CO2and vacuum packaging.3.explore the influence on the quality of rice between modified atmosphere packaging at100%CO2and vacuum packagingThis chapter main study vacuum packaging group, filling100%CO2packaging group and general packaging(herein referred to as:CK group) under the constant temperature and humidity chamber(temperature:15℃.relative humidity:50%).Rice viscosity, thermodynamic properties, aflatoxin and other physiological and biochemical changes was sample periodically to detect. The results showed that:Compared with ordinary packaging group, fuzzy rice sensory evaluation values were at the level to No.1(fuzzy values≥0.8), and it could delay an increase rice fatty acid value, reduce and sensory quality decreased LA enzyme activity under modified atmosphere packaging at100%CO2and vacuum packaging. Also there were more difficult to store rice paste and need more calories to make it completely gelatinized, and vacuum pack fully gelatinized heat required minimum. Therefore, we can know that both of modified atmosphere packaging at100%CO2and vacuum packaging can achieve rice storage preservation effect, the application of vacuum packaging or modified atmosphere packaging with100%CO2extended the storage duration of rice.