Preparation Of Rice Starch-glycerol Monopalmitate Complex And Its Effect On The Quality Of Rice Cake

Rice starch is an important raw material in food processing and production,and the ageing of rice starch plays a decisive role in the processing characteristics and edible quality of rice starch products,so it is important to improve the anti-aging property of rice starch to expand the application of rice starch.To slow down the aging of rice starch during food processing and extend the shelf life of rice starch products,this thesis systematically investigated the effect of glycerol monopalmitate on the aging properties of rice starch and its mechanism by using glycerol monopalmitate as an additive and studied the effect of rice starch-glycerol monopalmitate complex on the properties of rice cake,the main research contents and results are as follows:(1)The effects of rice starch compounded with monoglycerides of different chain lengths on its aging properties were investigated by using the compounding index,freeze-thaw stability and pasting properties as indicators.The results showed that glycerol monolaurate,glycerol monopalmitate and glycerol monostearate all had significant inhibitory effects on the aging of rice starch,with glycerol monopalmitate having the best anti-aging effect.The optimal conditions were 5%addition of glycerol monopalmitate,30 min compounding time and 80℃,and the compounding index was 86.54%and the water bleeding rate was 22.86%.(2)The solubility,swelling,freeze-thaw stability,pasting properties,rheological properties,thermal properties,microstructure,short-range ordering,crystalline structure and moisture distribution of rice starch and rice starch-glycerol monopalmitate complexes were determined using a rapid viscosity analyzer,rheometer,differential scanning calorimeter,scanning electron microscope,Fourier infrared spectrometer,X-ray diffractometer and lowfield nuclear magnetic resonance spectroscopy.The results showed that the solubility and swelling of rice starch decreased after compounding with glycerol monopalmitate;the freezethaw stability was improved;the peak viscosity,minimum viscosity,final viscosity,decay value and regeneration value decreased;the loss angle tangent value tan δ increased but was still less than 1;the paste start temperature TO,peak temperature TP,end temperature TC and enthalpy change AH all changed significantly;the short-range orderliness of starch The orderliness was reduced;the crystallinity was reduced by changing from A-type crystalline complex to V-type crystalline complex;the free water content was reduced and the aging resistance was enhanced.(3)The effect of the rice starch-glycerol monopalmitate complex on the quality of rice cake was investigated.The results showed that the peak viscosity,minimum viscosity,final viscosity and regeneration value of rice flour increased and then decreased with the addition of rice starch-glycerol monopalmitate complex,and the attenuation value did not change significantly;the storage modulus gradually increased,and the loss modulus and loss angle tangent value increased and then decreased;the specific gravity of rice cake batter and the weight loss of rice cake batter was the smallest at 15%addition.The rice starch-glycerol monopalmitate complex had significant effects(P<0.05)on the specific volume,sensory score,texture,aging properties and moisture distribution of rice cake.The quality of rice cake decreased with the increase of storage time,and the quality of rice cake was the worst at 7 d of storage,with the highest hardness and chewiness,and the lowest elasticity and cohesiveness,733.52,389.54,0.92 and 0.58,respectively;the aging enthalpy was the highest,and the content of bound and non-fluid water was the lowest;however,with the increase of rice starch-glycerol monopalmitate complex addition,the quality of rice cake However,with the increase of rice starch-glycerol monopalmitate complex addition,the quality of rice cake improved significantly.At 7 d of storage and 15%of complex addition,the rice cake had the least hardness and chewiness,the greatest elasticity and cohesiveness,483.12,276.87,0.93 and 0.62,respectively;the least aging enthalpy,the most bound water and non-flowable water content,the least specific volume,and the highest sensory score,and the best quality of rice cake.