Quality Changes Of High-oil Soybeans During Storage

As the main source of people's edible oil and vegetable protein,soybean is also one of the main grain reserves in China.Because it is rich in fat and protein,it has poor storage durability,and safety problems are prone to occur during storage.By studying the quality changes of high-oil soybeans during storage,In this paper,domestic high-oil soybeans and Argentine imported high-oil soybeans are selected as the research objects,and domestic ordinary soybeans are used as controls.After conditioning to target moisture(13.0%,15.0%),store at different temperatures(25°C,35°C),take regular samples and check the physiological and biochemical indicators,nutritional components and processed products of high-oil soybeans under different storage conditions(Oil,tofu)quality indicators are measured and analyzed in order to provide data reference for the safe storage of high-oil soybeans.the result shows:(1)With the extension of storage time,the moisture content of imported high-oil soybeans with a storage temperature of 35°C and an initial moisture of 15.0% showed a downward trend and then an upward trend.The electrical conductivity and malondialdehyde content of imported high-oil soybeans with two moisture levels showed a trend of first increasing and then decreasing.The moisture content,CAT activity,POD activity and PPO activity of the three kinds of soybeans stored under other conditions all showed a downward trend,while the electrical conductivity and malondialdehyde content all showed an upward trend.Correlation and factor analysis of variance show that the initial moisture has a very significant correlation with the CAT activity of the three kinds of soybeans,the storage temperature has a very significant correlation with the electrical conductivity and malondialdehyde,and the storage time has a significant or a very significant correlation with the physical and chemical indexes of the three kinds of soybeans.(2)With the extension of storage time,the crude fat content of the three soybeans under various storage conditions did not change significantly,the crude protein content showed a slight increase trend,the water-soluble protein content and NSI both showed a downward trend,The content of saturated fatty acids increased,but the content of unsaturated fatty acids decreased.Among them,the most significant changes were linoleic acid and oleic acid,and the total amount of amino acids decreased,but the protein secondary structure did not change significantly.And the higher the initial moisture content and the higher the storage environment temperature,the more significant the changes in nutrient components.The watersoluble protein content and NSI of the nutritional indicators of domestic high-oil soybeans and ordinary soybeans are mainly affected by storage temperature,while the water-soluble protein content and NSI of imported high-oil soybeans are greatly affected by the dual of initial moisture content and storage temperature.(3)When exploring the influence of high-oil soybeans on the oil quality during storage,The acid value and peroxide value of the three kinds of soybeans showed an upward trend with the extension of storage time,and the iodine value did not change significantly.Comprehensive comparison shows that high-oil soybeans,especially imported high-oil soybeans,have serious quality deterioration in all aspects during the storage process.When the raw grain is stored in the warehouse,the moisture of soybean grains should be reduced as much as possible,and the storage temperature should be kept low to ensure the safe storage of high-oil soybeans.Under the same storage conditions,the quality deterioration of domestic high-oil soybean oil is similar to that of ordinary soybean oil,and the oil quality deterioration of imported high-oil soybeans is more significant than that of the other two kinds of soybeans.The acid value of the three types of soybeans is significantly affected by the storage time,initial moisture content and storage temperature,and the peroxide value is significantly affected by the storage time.In addition,the acid value of imported high-oil soybeans stored under high temperature and high moisture conditions at the end of the storage period has been >3.5 mg/g,which is slightly unsuitable for storage.When exploring the effect of highoil soybeans on tofu quality during storage,the tofu yield and tasting scores of the three types of soybeans showed a downward trend,and the hardness,chewiness and glueiness of the texture characteristics showed an upward trend.The tasting score of domestic high-oil soybeans under high temperature and high moisture conditions has been lower than 70 points,which is slightly unsuitable for storage.The tasting score of imported high-oil soybeans with two moistures under high temperature conditions is lower than 70 or even lower than 60 points,reaching mild and severe levels and not suitable for storage.The tofu quality of ordinary soybeans is better than the other two soybeans at the end of the storage period..Tofu yield and tasting score are significantly or extremely significantly affected by storage time and storage temperature.Hardness,chewiness and glueiness are extremely significantly affected by storage time,and there is a significant correlation between tofu indicators.