Study On Preparation Of Instant Rice Bran Powder And Its Relative Properties

Rice bran is the main by-product of rice processing.It has large yield and rich nutrition,but the use ratio is low,which caused the waste of rice bran resources.This study choose whole rice bran as raw material,obtain the instant rice bran powder by extrusion,enzymatic hydrolysis and spray drying,then analyzed its nutrient composition,related properties and volatile flavor of raw rice bran,extruded rice bran powder and instant rice bran powder.Our aim is ready to provide theoretical basis for exploration and exploitation of rice bran.The main result were as follows:1.Base on the soluble dietary fiber(SDF)content of rice bran,though single factor and orthogonal experiments,the effects of barrel temperature,water content of the rice bran and screw speed on the content of SDF after extrusion were investigated.The results showed: the temperature of the extruded rice bran was 120?,the water content was 20% and the screw speed was 120r/min,the amount of enzyme SDF content is the highest.2.Base on the soluble carbohydrate content of rice bran,though single factor and orthogonal experiments,the effects of enzymatic hydrolysis temperature,enzymatic hydrolysis pH and enzyme dosage on ?-amylase enzymatic hydrolysis rice bran were investigated.The results showed: the content of soluble carbohydrate was the highest when the enzymatic hydrolysis temperature was 60?,pH 6.5 and enzyme dosage of5000 U/g.3.Base on the yield of instant rice bran powder,though single factor and response surface experiment,the effects of hot air temperature,hot air flow rate and feeding rate on spray drying rice bran hydrolysate liquid were investigated.The results showed: the yield of instant rice bran powder was the highest when the the dry air temperature was 160?,the hot air flow was 31.40 m3 /h,and the feeding rate was360 mL/h.4.The prepared instant rice bran powder is rich in nutrition.The content of fat,protein and ash in the dry base was 7.41%,11.98% and 7.40%,respectively.While the contents of K,Mg,Ca,Fe,Mn and Zn were 766.16 mg /100 g,377.56 mg/100 g,37.62 mg/100 g,12.05 mg/100 g and 5.83 mg/100 g,respectively.5.The particle property,basic property,powder property and rheological property of rice bran powder were analyzed.The results showed that the specific surface area of instant rice bran was significantly increased and the average particle size was significantly decreased compared with original rice bran,SEM images showthat the tissue structure of rice bran after extrusion is obviously expanded loose compared with original rice bran.The color difference of the three samples was small.The water holding capacity and oil holding capacity of instant rice bran were significantly decreased by compared with original rice bran,and the expansion force was not significantly different..The instant rice bran powder was reconstituted good,the wetting speed and the dispersing speed are fast,the solubility is good,and the quick solubility index is significantly different from that of original rice bran,the solubility is up to 77.60%.There were significant differences in the angle of repose,slip angle and bulk density of instant rice bran powder compared with original rice bran.The results of static rheology study show that the three rice bran samples belong to the pseudoplastic fluid at 20% concentration.6.The volatile flavor of rice bran samples were detected by SPME-GC-MS.The results showed that extruded rice bran powder had more than nine kinds of main flavor compounds compared with rice bran raw material.while the instant rice bran powder solution had less than nine kinds of main flavor compounds compared with rice bran raw material.