Releasing Energy from Rice Bran by Enzyme Supplementation and Microwave Treatment

Abstract

Three experiments were conducted to determine whether various exogenous enzymes (xylanase, lipase, and phytase) would enhance the nutritive value of rice bran for poultry. Water soaking and microwave treatment of rice bran, in combination with xylanase supplementation, were also examined both 'in vitro' and 'in vivo'. Experiment 1 was conducted in two parts. First, the ability of commercial glycanases to release sugars from rice bran 'in vitro' was examined. Full-fat or de-fatted rice bran (50 g) was incubated with 100 mL of water containing either a multi-activity glycanase (enzymes A; recommended dosage rate 800 mL/kg or 2 x 800 mL/kg) or a xylanase-based glycanase (Enzyme B; recommended dosage rate 500 mL/kg or 2 x 500 mL/kg). The mixtures were continuously shaken at 40°C for 24h. Negligible amounts of sugars were released from both full-fat rice bran and de-fatted rice bran by both enzymes at two dosage rates. Second, specific frequencies of microwave energy (68°C) were applied to a mixture (50:50) of rice bran and Enzyme A for 5,10, 20 or 30 min. Five minutes of microwave treatment released 3.5% free sugars from rice bran. Longer periods of treatment did not lead to increased release of sugars.