Effect of heating temperature on barley forming process as pellet feed

Abstract. As a main application type of feed, pellet feed owns many considerable advantages such as better palatability, high return, and avoiding automatic grading compared to mash feed. In the granulation production of pellet feed, lots of changes are happened such as exchange of moisture and thermal, deformation in physic shape by compression and chemical change like protein denaturation, starch gelatinization which will bring great influence to the final quality of pellet feed product. With the dramatically increasing tendency of corn price which is the traditional source of energy feed, development of irregular resource of energy feed become an efficient way gradually to meet the problem of the shortage and requirements of raw material nowadays. The outcome of these explorations not only could improve the plain conformation of compound feed and ameliorate its quality, but also help easing the contradiction between supply and demand in corn market by decrease price of feed material. Due to the advantage of well adaptability and stress resistance, barley is widely planted in different regions of China. Moreover, some researches indicate that with barley substitution to corn and soybean meal in certain degree feeding pigs and poultry, there shows improvement in fat hardness as well as carcass quality in poultry meat production while reduce the cost of feed intake in the same time. Therefore, by assistant of a self-designed and made forming apparatus, mash barley samples are decided to be the subjects of this research; some processing parameters are selected to fit and describe the actual pelleting production that including samples moisture, time of thermal maintain, size of crushing particle, etc. The primary study factor is heating temperature which reflect the thermal condition in pelleting; test level are decided as 60℃, 70℃, 75℃, 80℃, 85℃, 90℃ to meet different application occasion of pellet making. In the condition of piston-style extrusion in single hole, pressure-deformation data are collected by the function of universal testing machine that the apparatus load on. After the compression stage, several representative indexes for pellet feed quality are measured including pellet hardness, powder content ratio and pellet compression density. Basing on these study results, the properties of particle size distribution of barley is analyzed and compared with corn in same condition of ground thus to indicate the influence law. Moreover, combining with the change situation of forming quality indexes of pellet feed with different temperatures, the influence of thermal condition on the mash barley forming process and its outcome is analyzed. Meantime, by the discussion on the compression curve constituted by pressure and deformation, the influence of temperature on the changing tendency, slope and peak value of curve are studied; and in view of the separate theory, the curve is parted by friable parts, transition parts, compression parts and elapse parts for directional discuss for the material changing law and effect on final form of each part by the help of fit function in SPSS software. The result of this study could provide the change law of mash barley showed in compression forming process of pellet feed production as well as the fundamental test data of influence pattern when affected by heating temperature, while the purpose of better application for barley replacing corn as new type of energy feed in industry could be realize by those theory reference and practical assistance.