Study On The Modification And Processing Technology Of Ultra-high Pressure On The Germinated Brown Rice

Germinated brown rice refers to brown rice sprouting to proper shoot buds,mainly constituted by two parts,the germ and the endosperm with skin.Germinated brown rice is rich in nutrition,and contain a variety of bioactive components with health care function,for example,gamma aminobutyric acid(GABA).The nutritional and economic value of Germinated brown rice is higher than milled rice,and has a large market demand in domestic and abroad.Germinated brown rice sold on the market mostly is dry,when cooking,the rehydration is poor,and not easy to be digested.The author designs the rice production process without drying process for the energy saving and quality improvement of the germination and brown rice in the industrial production.However,making food with wet germinated brown rice need to eliminate odor from germination.Germination of brown rice is so rich in bran powder that difficult to swallow,it is necessary to improve its palatability and digestibility.In this paper,the taste of germinated brown rice was improved by adjusting the degree of germination,controlling the intensity of washing,and the high pressure treatment:1)The germination time was shortened to 18 h and the content of GABA remained unchangedThe traditional germination time of germinated brown rice was 24 h.Taking the aroma evaluation and GABA content of germinated brown rice as the index.By controlling the germination depth and washing intensity,the germination brown rice was optimized by orthogonal test.The method was as follows: immersed in citric acid / citric acid buffer solution at pH 6.0 for 4 h,then rinsing the clean acid solution,after germinating for 18 h at 32 °C,the rice was washed twice and the aroma was rich.The GABA retention rates were 81.10,81.78 mg/100 g dry roots in brown rice with germination time of 24 h and 18 h,respectively.There was no difference between the two,but the shallow germination could reduce the endosperm consumption.2)Light germination can reduce the panning strength,and remove the odor in brown rice.The odor substances of germinated brown rice are mainly 2-pentylfuran,2,3-dihydrobenzofuran and 4-vinyl-2-methoxyphenol.The relative content of 4-vinyl-2-methoxyphenol was 1.05%,2,3,9-dihydrobenzofuran was 6.89%,and 2-pentylfuran was 1.25% after germination for 24 h and rinsing for 3 times.The relative content of 4-vinyl-2-methoxyphenol,2,3-dihydrobenzofuran,2-pentylfuran were reduced to 0.84%,5.00% and 1.32%,respectively,after germination for 18 h and rinsing for 2 times and no rice bran flavor and smell.There is no detectable smell with the light germination.Reducing the washing time not only can avoid the loss of nutrients and active substances,but also save water and improve production efficiency.3)Ultra-high pressure treatment can improve the palatability of germinated brown riceReduced the rice bran powder of germinated brown rice surface,rice hardness and enhanced elasticity can improve the palatability of rice.The light transmittance of the extracted rice was increased from 95.30% to 98.37% in the rice treated with 400 MPa/5 min,which indicated that the ultrahigh pressure treatment can restrain the bran powder from the free surface of rice.Reduce its stimulation of the mouth when eating.The use of 200~400 MPa can significantly reduce the hardness and chewiness of germinated brown rice,enhance the elasticity,there had the lowest hardness and chewiness at 400MPa/15 min,indicating that high pressure treatment can improve the palatability of chewing the germinated brown rice.Germination brown rice was also easy to retrogradate,resulted in poor appetite.The rejuvenation can be characterized by the gelatinization characteristics of germinated brown rice.The gelatinization parameters of germinated brown rice were greatly reduced,and then decreased further after ultrahigh pressure treatment.There had lowest gelatinization temperature and final viscosity at 300 MPa/5min,lowest peak viscosity at 400 MPa/5min.The thermal stability and cold stability of the sprouted brown rice cereal were significantly improved with 300 MPa and 400 MPa for 5 min and the rate of regeneration was also inhibited.4)Ultrahigh pressure treatment can improve the digestibility of germinated brown rice in vitro.It is not easy to digest the germinated brown rice.If the relative content of fast digestible starch(RDS)is increased and the resistant starch(RS)is reduced,then the digestibility of brown rice will be improved.The content of RDS and RS in germinated brown rice treated with 300 MPa/5 min was 64.32% and 7.29%,respectively,while it was 55.41% and 11.86% in untreated group.The content of RDS in germinated brown rice stored for 2 days was still 61.43% at 400 MPa/5 min,which was much higher than that of the untreated group(47.47%);The RS starch content in treated group was 8.50%,which was lower than that untreated group(16.68%)under 400 MPa.It is obvious that high pressure treatment can improve the digestibility of germinated brown rice in vitro.