EFFECTS OF LIPIDS AND PROCESSING CONDITIONS ON DEGREE OF STARCH GELATINIZATION OF EXTRUDED DRY PET FOOD

Effect of fat type (poultry fat and beef tallow), fat content (0-75 g/ kg) and processing conditions (initial water content 160-200 g/kg; scr ew speed 200-400 rpm) on the degree of starch gelatinization of extrud ed, dry pet food was investigated. Fat content had the most prominent influence on starch gelatinization of the samples. Increasing the fat content significantly decreased the degree of starch gelatinization of the extrudates. Addition of beef tallow resulted in a lower degree of starch gelatinization as compared to poultry fat. Increasing the init ial moisture decreased the degree of starch gelatinization of the extr udates. However, the effect was nor very significant within the range studied. Interactive effects of screw speed and fat content on starch gelatinization of dry pet foods were observed. (C) 1997 Academic Press Limited.