Lactic Acid Bacteria Fermented Modified Waxy Corn And Its Application

Waxy corn is rich in nutrients and is a coarse grain with high edible value.The sticky bean bun with waxy corn as the main raw material has a sweet taste and sticky texture,which is very regional.With the industrialization of traditional food production and the advocacy of a diversified diet structure of "coarse grains and fine production",sticky bean buns have become one of the focal points of Longjiang’s characteristic traditional foods.Waxy corn flour lacks gluten protein and has a high content of amylopectin,so it is difficult to form dough and has excessive viscosity,which makes it difficult for waxy corn to be widely processed and utilized.The production of traditional sticky bean buns relies on natural fermentation,the fermentation process is slow,the production cycle is long,and the product quality is difficult to control,which lays hidden dangers for food safety.Aiming at the above-mentioned problems,this study uses pure lactic acid bacteria fermentation method to improve waxy corn flour,and analyzes the influence of fermentation on its processing performance,physical properties,and molecular structure,and then optimizes the processing of sticky bean buns by adjusting the fermentation process parameters The conditions are as follows:(1)The pH of the fermentation broth,total acid content,and the basic composition and processing performance of waxy corn flour were measured at different fermentation times,and the microstructure of waxy corn flour was observed by scanning electron microscope.Lactic acid bacteria fermentation changed the waxy jade powder composition.With the extension of the fermentation time of lactic acid bacteria,the pH decreases and the total acid increases;under the action of fermentation,the crude protein,fat,cellulose and ash content of waxy corn meal decreases significantly,and the starch content increases;the water absorption index increases;the powdery color shallow.Scanning electron micrograph shows that the grain structure of waxy corn flour is loose after fermentation,the cross-linking between grains gradually disappears,the size of starch granules is different,there are more edges and corners,the surface is damaged,and some cracks and holes appear.(2)The alkali extraction method is used to extract starch from fermented waxy corn flour,and the physicochemical properties of waxy corn starch before and after fermentation(solubility,swelling power,transparency,retrogradation,freeze-thaw stability,gelatinization properties,and thermodynamic properties))Perform the measurement.Lactic acid bacteria fermentation changed the physical and chemical properties of waxy jade starch.Fermentation treatment increases the solubility and swelling power of waxy corn flour particles,enhances the condensability,and slightly reduces the freeze-thaw stability.The peak viscosity and disintegration value of starch gelatinization properties first increase and then decrease with the extension of fermentation time,and the final viscosity and retrogradation value increase.In the thermodynamic properties,the gelatinization start temperature decreases with the extension of the fermentation time,the enthalpy value increases with the extension of the fermentation time,and the heat resistance stability of starch granules is enhanced.Fermented modified waxy corn flour has significant improvements in thermal stability and retrogradation resistance.(3)Based on the preliminary exploration of the physicochemical properties of waxy corn starch,the molecular composition and structure of waxy corn starch were analyzed,including amylopectin content,molecular group,polarized cross and microstructure.The relative content of waxy corn starch amylopectin in the fermentation process is lower than that before fermentation.Fourier infrared spectroscopy results show that the waxy corn starch after fermentation has similar absorption peaks to unfermented starch molecules;the results observed by polarized light microscope show that the polarized light cross of starch has not been destroyed,which indicates that the microbial metabolism in the fermentation process,Produces organic acids and enzymes,acts on the amorphous area of starch,and the crystalline structure is not destroyed.Scanning electron microscopy results show that the surface of the waxy corn starch after fermentation has been eroded seriously,the holes and irregular shapes are obvious,and the proportion of damaged starch is increasing,but the granular nature of starch has not changed significantly.(4)The fermentation process for the production of sourdough with sticky beans is explored.The effects of fermentation time,fermentation temperature,strain addition,and raw material particle size on the quality of sticky bean buns were investigated through single factors,and response surface optimization experiments were designed on this basis to obtain the best fermentation process parameters:fermentation time was 7 d,fermentation The temperature is 17℃,the amount of bacteria added is 1.2%(m/m),and the raw material particle size is 4 mm.The sensory score of the sticky bean buns prepared under the optimal fermentation process parameters can reach 95.20,which is higher than that of the commercially available sticky bean buns.The texture measurement results show that compared with the commercially available natural fermented bean curd,the gum bean curd prepared under the best fermentation process parameters has better coordination in hardness,viscosity and elasticity,and the product has moderate hardness,good chewiness,rich taste and improved In addition,waxy corn foods are relatively sticky and not elastic,and they also have certain advantages in shortening the fermentation time.