Extraction Optimization Of High-Amylose Corn Starch And Its Applications In Food

According to statistics,currently there are about 537 million adults with diabetes in the world,and 116 million diabetes patients in China.As a good source of resistant starch,highamylose corn starch can effectively slow the rise of blood sugar and is one of the ideal food materials for diabetes patients.In the traditional wet milling extraction process,the extraction rate of high-amylose corn starch(43%-53%)is lower than that of normal corn starch(65%-72%),and the protein content(>1%)is higher,which greatly limits the application of highamylose corn starch.Therefore,to reduce the production cost of high-amylose corn and expand product its application,it is necessary to explore an effective extraction process to improve the extraction rate and purity of high-amylose corn starch;Based on the slow sugar increase characteristics of high-amylose corn starch,it has been widely used in Western countries.However,due to insufficient raw material production and poor quality in China,its products have not been promoted domestically.Therefore,this study focuses on high-amylose corn as the main research object.On the basis of traditional wet milling processing,ultrasonic protease extraction of high-amylose corn starch was added,and its extraction process was optimized;The high amylose corn starch was used as raw material in soda cracker and instant noodles through different gradient addition and processing methods,and the effects of high amylose corn starch and processing methods on the texture,sensory and in-vitro starch digestibility characteristics of soda cracker and instant noodles were analyzed to provide basis for the related food application of high-amylose corn starch in China.To explore the effects of ultrasound power,protease dosage,treatment time,and treatment temperature on the yield and purity of high-amylose corn starch,based on the results of a single factor experiment,the Box-Behnken experimental design was used to optimize the ultrasound protease extraction process parameters.The optimal extraction process parameters were determined as follows: ultrasound power 120 W,protease dosage 0.3%,treatment time36 min and treatment temperature 55℃,the starch yield was increased to 61.27% and the starch protein content was decreased to 0.44% when compared to the conventional wet milling of high-amylose corn(48.94% and 1.75%,respectively).The high-amylose corn starch extracted from wet milling with simultaneous ultrasonication and protease treatment had a crystalline structure,relative crystallinity,pasting properties,thermal properties,and enzyme digestion similar to that extracted from the conventional wet-milling.To explore the effects of high-amylose corn starch addition(40%,50%,60%)and baking temperature(130℃,150℃,170℃)on the texture,sensory,and digestive characteristics of soda cracker.When the addition amount of high-amylose corn starch was 40%-60%,the specific volume of soda biscuits decreased by 0.8 mL/g-1.01 mL/g,and the breaking force decreased by 1506 g-3735 g.The overall color and sensory evaluation were lower than those of blank soda cracker.After 16 hours of simulated in-vitro digestion,the highest starch digestibility decreased by 36.67%,and some starch particles still maintained intact starch morphology through microscope observation;When the baking temperature increased from 130℃ to 70℃,the specific volume of high-amylose corn starch soda cracker increased by 0.15 mL/g-0.25 mL/g,the breaking force increased by 526 g-1189 g,and the starch digestibility increased by 6.91%-9.14%.High amylose corn starch has a negative impact on the texture and sensory properties of soda crackers,but increasing the baking temperature can achieve a certain degree of improvement.Compared to blank soda biscuits,high amylose corn starch enhances the digestive resistance of soda cracker.To explore the effects of high-amylose corn starch addition(30%,40%),steaming method(direct steaming,steaming cold storage steaming)and drying method(hot air,frying)on the texture,sensory and digestive characteristics of instant noodles.The addition of high-amylose corn starch made holes of different sizes in instant noodles.When the addition amount was 30%-40%,the chewiness of fried instant noodles increased by 25%-114%,and the tensile force decreased from 91.15 g to 46.17 g;The hardness of hot-air dried instant noodles decreased from 4777 g to 3185 g,the resilience decreased by 26.92%,the tensile force decreased from 88.52 g to 22.35 g,and the firmness decreased by 50.9%.Compared with the starch digestibility of blank fried and hot-air dried instant noodles(64.91%,73.82%),the highest digestibility of fried instant noodles with high amylose corn starch and hot-air dried instant noodles decreased by 21.19% and 30.87%,respectively;The restreaming processing method will further improve the digestibility of fried and hot-air dried high-amylose corn starch instant noodles,which can increase 1.39%-2.49% and 3.67-8.37% respectively,but has no significant impacts on texture and sensory;In addition,different drying methods have little effect on the anti-digestibility of instant noodles,but the high-amylose corn starch instant noodles produced by hot air drying are generally better than fried instant noodles in sensory scores.