Analysis Of ?-amino Autyric Acid Content In Geminated Brown Rice And The Changes During Storage

Germinated brown rice is a nutrient-rich whole grain food,which has an important role in alleviatingsome chronic diseasesandhuman health because that it is rich in ?-aminobutyric acid(GABA)and a variety of nutrients.Domestic enterprises have been producing germinated brown rice and its products,however,there is no uniform method for the detection of GABA in germinated brown rice,and the content of GABA in the same germinated brown rice products is different by different method.In this dissertationthe pretreatment conditionswere selected,a high performance liquid chromatography(HPLC)method with online precolum derivatization for determination of GABAin germinated brown rice was established.Further the differnent of cultivars on edible quality of germinated brown rice was discusses.The changes of the contents of GABA in the baking,cooking and ultrahigh pressure process were studied.The changes of the nutrient quality,chrominance and volatile componentsin storage process of germinated brown rice with different moisture content at 4??25??35? were studied.Thus it plays the directive fuction of germination brown rice during the storage and processing.The results indicated that the ultrasonic extraction was the most stable and rapid among the five pretreatment methods.Then single factor test and Box-Behnken response surface was used for process optimization.By HPLC method with online precolum derivatization determinating GABA in germinated brown rice,Online pre-column derivation 2min were reacted by using orthophthalaldehyde(OPA)derived reagents and sample after mixing 10 times,sample was HPLC separated on acolumn.The retention time of GABA was about 16.9 min,good linearity was observed in the range of 5~50 mg/L.Detection limit of 0.33 mg/L,quantitative detect limit of1mg/L,the average recovery was 96.93%(RSD=2.13%).the precision and reproducibility were good.The germination rate,GABA content,basic components,chrominance,flavor,texture and sensory quality of different varieties of germinated brown rice were different.the GABA content of germination brown rice was Indica germinated brown rice> waxy germinated brown rice>japonica germinated brown rice and the southern> northern;the hardness,chewiness,cohesiveness and gumminess of japonica were the maximum.the resilience of waxy germinated brown rice wasthe maximum;the sensory score was waxy germinated brown rice> indica germinatedbrownrice> japonica germinated brown rice.The edible quality of 15 year germinationbrown rice was better than the 14 year' and the 13 year'.Baking and cooking processing significantly effected GABA content in germinated brown rice(P<0.05),the content of GABA decreased significantly with the increase of processing time,the high pressure cooking could lose more GABA than natural cooking under the sametime,the natural cooking germinationbrown rice could be considered.the effect of Ultrahigh pressure processing on GABA content was significant(p<0.05),GABAloss of high-pressure short-term treatment was less,and if appropriate time was selected,the content of GABA was increased.The falling range of moisture contentof 14.88%,17.89% of the germinated brown rice were high temperature(35 ?)> room temperature(25 ?)> low temperature(4 ?)during storage,the 8.67%,10.37% humidity of the germinated brown rice were relative stability;low temperature and low moisture content of germinated brown rice surface color changed little;germination brown rice rancidity were moisture content of 17.89% > moisture content of 14.88% > moisture content of10.37% > moisture content of 8.67%;the speed of rancidity of germinated brown rice was35 ?>25 ?>4 ?;GABA content loss rate 25? and 35?> 4?,low temperature could effectively inhibit the reduction of GABA content.The falling range of GABA content was moisture content of 17.89% and 8.67%> moisture content of 14.88% and 10.37% of the germinated brown rice,appropriate moisture content could effectively inhibit the reduction of GABA content;the volatile components increased gradually during storage,whichthe hydrocarbons was increasing,the unsaturated hydrocarbon chain gradually becomes saturated hydrocarbon chain,and the hydrocarbon chain length changed gradually,indicating that the oxidation reaction occurred.