Effects of gradually increasing drying temperatures on energy aspects, fatty acids, chemical composition, and in vitro ruminal fermentation of acorn.

Acorns are commonly used to meet energy, protein, and mineral needs of livestock in various parts of the world. However, since acorns have quite a high moisture content at harvest, they should be stored as dried to prevent loss of nutrients and spoilage throughout storage periods. The aim of this study is to determine the drying kinetics, color, energy aspects, crude protein, crude ash, crude oil, fatty acid composition, ADF, NDF, condensed tannin, and mineral composition properties of acorns dried at gradually increasing drying temperatures. Drying processes were carried out in an air-convective dryer at temperatures of 40, 60, 80, 100, and 120 °C. The Logistic model was identified as the best model for describing current drying conditions. Increasing drying temperatures reduced L* (lightness) values and increased thermal efficiency and effective moisture diffusion values. In terms of energy efficiency, the best outcomes were achieved at 80 °C and 120 °C drying temperatures. Drying temperatures had highly significant effects on nutritional traits of acorn samples. Increasing drying temperatures increased fiber content, gas-methane production, and energy values and reduced crude protein and oil contents. Some minerals decreased and some others increased with increasing drying temperatures. Increasing drying temperatures caused slight changes in fatty acid compositions. In terms of animal drying and feeding characteristics, it was determined that a drying temperature of 80 °C was ideal for acorn drying.