| Fried glutinous-rice food is a kind of popular traditional Chinese snack,but its related research is very rare.In this study,pure waxy rice and water were used as raw materials to make fried waxy rice cakes,and studied the influence of frying time,temperature and water content on its quality.In order to research further on the reaction between starch and oil during frying,took high amylose corn starch as control group.The combination of starch and lipids in frying process was studied,and the effect of initial moisture content on the formation of two kinds of starch complexes also were explored.The properties of starch-lipid complexes in the process of frying were studied and its structure was analyzed.The results showed as follows:1.Based on sensory score as the benchmark,the factors of frying time,frying temperature and water adding amount were taken as influencing factors.The optimal preparation process was obtained by single factor and orthogonal test:The water addition amount was 65g for per 100g glutinous rice flour,the frying temperature was 170?,the frying time was 6 min,respectively.The sensory score for the resulting product was 80.5.2.The quality of the fried waxy rice cake is influenced by the frying time,temperature and the amount of water added.Results show that the frying time mainly affected the viscosity and elasticity of cakes.Frying temperature had a significant effect on brittleness of cakes,while moisture content had influence on the brittleness,viscosity and elasticity.The longer the fryting time was,the higher the oil absorption rate of the rice cakes had.When temperature was 160? the oil absorption rate of cakes was lowest,while the water addition amount was 65 g/100 g waxy rice flour the rate was least,too high or too low would cause rising in oil absorption.3.The method of headspace solid-phase microextraction(HS-SPME)was optimized to extract the flavor substances of fried waxy rice cake.The results detected by GC-MS showed:there are 68 kinds of flavor compounds in fried rice cake were obtained,including 11 hydrocarbons,6 alcohols,20 aldehydes,2 acids,9 kinds of ketones,5 kinds of esters,11 Pyrazine,2 furans,1 furan and 1 morpholine.The main compounds of these compounds are aldehydes,Pyrazine and ketones,the relative content is 68.71%,8.36%and 7.63%,respectively.The second is 2.99%of alcohols,2.98%hydrocarbons,the least content is esters,furans,acids and other,the content is 2.20%,2.15%,0.57%and 0.74%respectively.4.Waxy rice starch and high-amylose corn starch were fiyed in refined rapeseed oil respectively to obtaine starch-oil complex before defatting and smashing.The properties and morphology of complexes were detected.The results of complexing index and fourier transform infrared spectroscopy showed that both waxy rice starch and corn starch were able to form complexes with oil during the frying,and the initial moisture content has an important influence on the compound degree.Under the condition of the initial moisture?22%,both starches could be compounded with the oil,and the maximum complexing index was found when the water content was 40%.Fatty acids amount in complexes analysed by the GS-MS showed that the type and content of the complexed fatty acids were related to the fatty acid composition of the frying oil,and the high-amylose corn starch was able to complex more fat than the waxy rice starch,and the complexes were more stabler than that of the waxy rice starch.Scanning electron microscopy showed that the apparent morphology of waxy rice starch changed significantly when the initial water content up to 22%,while some corn starch puffed to rupture.The two kinds of starch both lost the starch particle morphology and produced intricate pore structure when water content came to 40%.After Nile red staining,under the fluorescence microscopy,the fat in complex showed gold yellow fluorescence.The fluorescence in corn starch group were significantly brighter than the waxy rice group.Fluorescence microscopy and confocal laser scanning microscopy showed that the lipid distribution of complexes were different between the two kinds of starch.Oil droplets in waxy rice starch presented finely small and scattered distribution,whereas the bigger range and more uniform oil distribution showed in corn starch. |
PDF Full Text Request