The Study On Chemical Composition And Antioxidation Of Rice And Byproducts

The chemical composition and antioxidation of rice and byproducts from different producing area were studied in this paper. Fatty acids and volatile oil constituents of rice and byproducts were analyzed and compared by gas chromatograph-mass spectrometry.Oleic acid,linoleic acid and palmitic acid are the primary fatty acids. The voilatile oil are mostly constitute of aldehyde,ketone,ester compounds and alkyl compounds. The flavonoids content was determined by ultraviolet spectrophotometry. The results show that the flavonoids content in different rice ranges from 0.1984 to 0.3222 mg/g.The naringin content was quantitative analyzed using solid phase extraction-high performance liquid chromatograph.The naringin content ranges from 0.02720 to 0.1188μg/g .The microelements were determined by inductively coupled plasma-mass spectrometry.The microelement of Zn,Fe,Cu content are higher in rice.The antioxidant capacity was determined by fluorescence spectrophotometry.The results conclude that rice and byproducts have stronger antioxidation.The soxhlet extraction method was used to extract fatty acids in rice and byproducts ,then determined by GC-MS. Unsaturated fatty acids are the dominant fatty acids,Their content is different on account of different producing area.The steam distilled and simultaneous distilled extraction method were used to extract volatile oil in rice and byproducts.According to GC-MS analysing the volatile oil of rice are mostly constitute of butylated hydroxytoluene,butylated hydroxyanisole and alkyl compounds.The volatile oil of byproducts are mostly constitute of azulene,2-pentyl fural,nonanal and acetic acid octyl ester.The flavonoids were extracted by ultrasonic method. The optimum extraction condition were ascertained by orthogonal design experiment as follows: solid and liquid ratio is 1:10,ultrasonic temperature is 0℃,ultrasonic time is 15 min,ultrasonic times are 4. The flavnoids are determined using naringin as standard.The naringin in rice was quantitative analyzed by SPE-HPLC,The recovery ranges from 95.81% to 104.2%.The relative standard deviation is less than 1.768%.The sample was dealt with Microwave digestion.Through ICP-MS the microelements such as Fe,Zn,Cu,Ge,Se,Cd,Hg,Pb were determined. The recovery ranges from 91.18% to 111.3%.The relative standard deviation is less than 6.240%. The antioxidant capacity was observed and compared through FS,the system of benzenecarbonic acid-Cu+-peroxyl was used.While the pH of buffer solution is 6.50, the molar ratio of benzenecarbonic acid and peroxyl is 7:200,the concentration of Cu+is 0.8000×10-5 g/mL,the fluorescence intensity is the strongest.In this condition scavenging capacity of rice and byproducts to hydroxyl radicals ranges from 83.20% to 95.60%.