Qu Chenling, Wang Xueke, Wang Ziwei, Yu Songcheng, Wang Dianxuan
College of Grain Oil and Food Science, Henan University of Technology.
College of Public Health, Zhengzhou University.
J Oleo Sci. 2020 May 2;69(5):403-412. doi: 10.5650/jos.ess19249. Epub 2020 Apr 13.
Peanuts are usually with high moisture after harvest and must be dried to prevent mildew. Hot air drying is the most commonly used method for peanut drying. The purpose of this study was to evaluate the drying temperatures on the peanut qualities. In this paper, fresh peanuts were dried with solar radiation (control group) and hot air at 35-60°C until the moisture content of peanut reduced below 10%. The physical (texture, damaged percentage of red testa and breakage percentage of peanut kernel), physiological (germination) and biochemical (the contents of vitamin E and aflatoxin B; acidity values, iodine values, peroxide values and fatty acid composition of peanut oil; solubility, emulsifying, foaming, water-holding capacity and oil-binding capacity of peanut protein) properties of peanut kernel were determined under different drying conditions (solar radiation, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C). The results showed that hot air temperatures had obvious influences on peanut qualities. The damaged percentage of red testa and breakage percentage of peanut kernel increased remarkably when the drying temperatures were above 45°C. Meanwhile, when drying temperatures were more than 45°C, the acid value and peroxide value of the extracted oil increased significantly. Furthermore, some properties exhibited prominent changes when the temperatures were higher than 50°C, such as hardness, brittleness, germination percentage, and the Vitamin E content of peanut kernel. In addition, the research results revealed that hot air can increase hydrophobicity of peanut protein and affect the functional properties of peanut protein. Therefore, it could be concluded that peanut should be dried by hot air below 45°C for quality maintenance. It also provided reference to choose suitable drying temperatures based on the final use of peanut.
花生收获后通常含水量较高，必须进行干燥以防止霉变。热风干燥是花生干燥最常用的方法。本研究的目的是评估干燥温度对花生品质的影响。本文采用太阳辐射（对照组）和35 - 60°C热风对新鲜花生进行干燥，直至花生含水量降至10%以下。测定了不同干燥条件（太阳辐射、35°C、40°C、45°C、50°C、55°C、60°C）下花生仁的物理性质（质地、红皮损伤率和花生仁破损率）、生理性质（发芽率）和生化性质（维生素E和黄曲霉毒素B的含量；花生油的酸值、碘值、过氧化值和脂肪酸组成；花生蛋白的溶解性、乳化性、起泡性、持水能力和结合油能力）。结果表明，热风温度对花生品质有显著影响。当干燥温度高于45°C时，红皮损伤率和花生仁破损率显著增加。同时，当干燥温度超过45°C时，提取油的酸值和过氧化值显著增加。此外，当温度高于50°C时，一些性质发生了显著变化，如花生仁的硬度、脆性、发芽率和维生素E含量。此外，研究结果表明热风会增加花生蛋白的疏水性并影响花生蛋白的功能性质。因此，可以得出结论，为保持品质，花生应采用45°C以下的热风干燥。这也为根据花生的最终用途选择合适的干燥温度提供了参考。
