发芽处理对糙米营养品质、理化特性与微观结构的影响OA

To explore the changes in nutritional components,physicochemical properties,and microstructure of brown rice during germination,this study identified the nutritional components of brown rice at different time points(0,24,and 48 h)of germination.The gelatinization property and microstructure of brown rice were studied through a rapid viscosity analyzer(RVA)and a scanning electron microscope(SEM).The short-range order and crystallization of brown rice during germination were analyzed by Fourier transform infrared spectroscopy(FTIR)and X-ray diffraction spectroscopy(XRD).The results showed that germination significantly enhanced the α-amylase activity of brown rice.The α-amylase activity of brown rice germinated for 48 h was 5.47 U/g,which was 8.7 times that of brown rice germinated at 0 h.Compared with germinated brown rice at 0 h,the brown rice germinated for 48 h showed decreases of 11.97 and 1.80 percentage points in the content of total starch and amylose,while the reducing sugar content and total free amino acid content increased from 1.04%to 4.81%and from 0.085%to 0.330%,respectively.Meanwhile,the content of mineral ions including calcium and sodium also increased.Notably,the γ-aminobutyric acid(GABA)content in brown rice increased from 77.70 mg/kg to 322.57 mg/kg after germination for 48 h.Germination treatment significantly reduced the short-range ordered structure and relative crystallinity of brown rice,accompanied by an increase of the amorphous region.SEM observations further indicated that the microstructure of germinated brown rice became looser.The RVA data showed that the viscosity parameters of germinated brown rice significantly decreased.This demonstrated that germination promoted the degradation of starch,which made it easier to gelatinize,enhanced its thermal stability and retarded the starch retrogradation.In conclusion,germination treatment destroyed the compact structure of brown rice and effectively improved its nutritional value.