Effects of Triple-Pass Drum Dryer on Enzyme Activity and Quality of Forage Oats

HighlightsOats retain better quality under outlet conditions of 100°C to 110°C and 0.169 to 0.172 kg water/kg dry air.Inactivation of POD maintaining the pectin content increases the oats’ hardness.The color-changing is alleviated when higher RH and high-temperature drying.DARE-EM method can evaluate the forage oats’ overall quality.Abstract. Mechanical drying processing influences the quality changing of the materials. To investigate the differences, the qualities of mechanical dried and naturally dried forage oats were evaluated. The changes in dried oats' enzyme activity, color, texture, and nutritional value were analyzed. A combined analysis of the decision alternative ratia evaluation system (DARE) and entropy weight method (EM) were adopted to evaluate the overall qualities of oats. The results showed that the drum drying process performed better than the natural drying process. Compared with natural drying, oat grass can inactivate enzymes such as CAT and POD quickly during drum drying, shorten the time of browning reaction, and further reduce the loss of color and nutrients. Research showed that the dryer's outlet air temperature and relative humidity severely affected the quality of dried oats. The most suitable conditions were the outlet air temperature of 100°C to 110°C and humidity ratio of 0.169 to 0.172 kg water/kg dry air. Under these conditions, the dried oats’ color change was alleviated, and antioxidant enzymes were inactivated. The retention of the plant cell wall and pigment ensured the quality of oat hay. These results can provide the reference for producing high-quality forages. Keywords: Color, DARE-EM, Enzyme activity, Forage oats, Nutrient content, Triple-pass drum drying.