Ultrasonic Enzymatic Reaction of Brown Rice Grains

Experimental method (1) Under room temperature conditions, the brown rice kernels (water content 14.8%) were soaked for 0, 15, 30, 45, 60, 75, 90 and 105 min with deionized water, centrifuged, and the surface of the rice grains was wiped off with filter paper. Moisture, moisture measurement. Each sample. (2) At room temperature, in the ultrasonic field (25W, 30kHz), the brown rice seeds (water 14.8%) were soaked for 0, 15, 30, 45, 60, 75, and 90 minutes with deionized water, and then centrifuged. The moisture on the surface of the rice grain was wiped off with a filter paper to measure moisture and organic phosphorus.

Two parallel samples were taken for each sample, and the arithmetic mean was taken as the result. (3) Weigh 5g of brown rice into a 100ml triangle bottle, add 50ml of deionized water, add 0.4U/ml phytase working solution 4ml, soak for 0, 15, 30, 45, 60, 75 and 90min respectively, centrifuge The water on the surface of the rice grain was wiped off with a filter paper to measure the phosphorus.

Two parallel samples were taken for each sample, and the arithmetic mean was taken as the result. (4) Weigh 5g of brown rice into a 100ml triangle bottle, add 50ml of deionized water, add 0.4U/ml phytase working solution 4ml, and treat it by ultrasound (25W, 30kHz) 0, 15, 30, 45, 60 respectively. After 75 and 90 min, the cells were centrifuged, and the water on the surface of the rice grains was wiped off with a filter paper to measure the phosphorus. Two parallel samples were taken for each sample, and the arithmetic mean was taken as the result. (5) Since more than 90% of the organic phosphorus in the brown rice exists in the form of phytate phosphorus, the content of organic phosphorus in the brown rice can be calculated by the difference method between total phosphorus and inorganic phosphorus.

The sample is not digested during the determination of inorganic phosphorus, and the determination of total phosphorus is subject to digestion. Results and Discussion Effect of Ultrasound on Water Absorption of Brown Rice Grains The reaction of phytase to hydrolyze phytic acid must be carried out with the participation of water molecules. The phytase hydrolysis reaction is not only related to the moisture content of the system, but more importantly to the availability of water in the reaction system. Enzyme-based enzymatic reaction, in addition to having a substrate effect, water can also act as a transport medium and promote the activation of enzymes and substrates by hydration.

After 30 minutes of ultrasonic treatment, the moisture content of brown rice seeds was 17.9%, an increase of 20.9%, which was 10 times of the moisture increase (2.1%) of brown rice without ultrasonication. After 30 minutes of ultrasonic treatment, the water absorption speed suddenly increased and the water absorption was rapid. The increase may be due to the fact that the endosperm starch begins to absorb water and swell. It can be seen that the ultrasonic wave can effectively strengthen the mass transfer process and accelerate the penetration rate or mass transfer rate of the foreign matter. According to Fig. 2, it can be judged that after the ultrasonic action for 30 minutes, the foreign matter has penetrated into the aleurone layer, and the exogenous phytase can directly act on the substrate (phytic acid), thereby realizing the purpose of enzymatic hydrolysis and anti-nutritional factors. Ultrasonic can enhance the mass transfer process mainly depends on cavitation and its effects.

After the phytic acid molecule is degraded by phytase, the main product formed is inositol diphosphate. Phosphorus in brown rice samples includes inorganic phosphorus, phytate phosphorus, phospholipids, etc., so there is also a certain amount of phosphorus in the brown rice sample. Conclusion Ultrasonic has the function of strengthening the mass transfer process, which can accelerate the penetration rate of brown rice exogenous materials and shorten the reaction time. The appropriate power ultrasonic wave can catalyze the enzyme activity and promote the enzymatic hydrolysis reaction. Studies have shown that when phytase hydrolyzes phytic acid in brown rice, the suitable parameters are ultrasonic power 25W and ultrasonic action time 30min.