The objective of this study was to determine the effect of the moisture content and pellet mill type on the physical and chemical characteristics of Italian ryegrass (IRG) pellet. Moisture content of raw material significantly (p<0.05) affected IRG pellet formation. Moisture content at 25% was the best condition for IRG pellet formation in terms of shape, power load and temperature changes. The hardness of pellet was decreased when moisture content was increase. However, the hardness of pellet was not affected by pellet mill type. Moisture content at 30% dramatically (p<0.05) decreased the durability compared to moisture content at 25%. Dry matter content of IRG pellet was increased (p<0.05) after pelleting. Total count of microorganism was decreased in pellet due to pressure heat and moisture losses during the pelleting process. These results indicated that the proper moisture content of Italian ryegrass pelleting would be at 25%. In addition, Roll & flat die type would be more suitable than Ring die and Die & flat die type in IRG pelleting. Pelleting works would be beneficial for improving forage quality and long storage.

The effects of pellet moisture content on physical properties (expansion ratio, density and breaking strength) of vacuum-puffed Yukwa (non-oil puffed Yukwa) were investigated in this study. The Yukwa was made from the waxy rice steeped at 25 and 30oC for 3, 5 and 10 days with pellet drying times (6, 8 and 10.5 hr), respectively. As the drying time increased from 6 to 10.5 hr at 50oC, the highest value of pellet moisture content (29.4%) was found in the samples made from the steeped waxy rice at 25oC for 5 days after 6 hr drying, while the lowest value (16.3%) was found at 25oC for 3 days after 10.5 hr drying. Both redness and yellowness values of vacuum-puffed Yukwa increased as the drying time increased. The expansion ratio of Yukwa was greatly affected by drying time, ranging from 2.07 (26.8% pellet moisture content) to 7.01 (24.0% pellet moisture content). From the data, it was concluded that the pellet moisture content had a significant influence on the physical characteristics of vacuumpuffed Yukwa. With vacuum puffing condition of 3 min heating and 2 min puffing, the pellets with about 25% moisture content showed higher expansion ratio, and lower density and breaking strength.