Optimization Of Enzymatic Hydrolysis Of Castanea Henryi With Two Enzymes And Application Of Hydrolysates

Castanea henryi has high nutritional value,and can be eaten directly,but can also be used in cooking,making coleslaw and pastry.In recent years,as the intensive management of Castanea henryi seed industry,the number of Castanea henryi seeds has been increasing and the production had begun to take shape.As the scale of its production continues to expand,the higher requirements were also put forward in deep processing.Therefore,it is of great practical significance for the exploitation and utilization of Castanea henryi to carry out in-depth research on the theory and technology of processing characteristics and utilization of Castanea henryi.The seeds of Castanea henryi were wet-milled with a shear machine,and the physical chemistry characteristics of the seeds were determined.At the same time,based on the technology of wet-shearing,the enzymatic hydrolysates of Castanea henryi were prepared by double-enzyme method and added into bread.This study provided a theoretical basis for the application of Castanea henryi enzymatic hydrolysate in flour products.The results of the study are as follows:1.When the shearing parameters of the shearing machine were set to the shearing frequency 35 Hz,the shearing time 11 min,the ratio of material to liquid 1:10,the chestnut was sheared wet,the experiment set gelatinization time,adding amount of double enzyme,p H of enzyme,time of enzyme and temperature of enzyme action as five factors,and used L₉（3⁴）orthogonal table to carry out orthogonal optimization experiment,the sugar content,light transmittance and centrifugal precipitation rate were evaluated.The results showed that the gelatinization time was 30 min,the p H value of enzymatic hydrolysis was4.0,the addition of two enzymes was fungusα-amylase:glucoamylase=0.2 g/L:0.4 m L/L,the enzymatic hydrolysis temperature was 55℃,and the enzymatic hydrolysis time was 70 min.The enzymatic hydrolysis had the best effect,the sugar content and light transmittance of the solution system were the highest,the centrifugal precipitation rate was the highest,and the special aroma of Castanea henryi was maintained.2.Compared with the original starch,the starch obtained from theenzymatic hydrolysis of Castanea henryi has the following characteristics:（1）The surface of starch was flat and smooth,and no surface collapse,breakage and depression were observed,but the effect of other crushing methods could be achieved,and the particle size was about 10 pm.（2）The vibrational density of Castanea henryi starch obtained by shear enzymatic hydrolysis was higher than that of Castanea henryi starch without shear enzymatic hydrolysis,reaching 0.711 g/cm³.（3）Compared with the original starch,the water-holding capacity of Castanea henryi starch was 15.88%.（4）The light transmittance of Castanea henryi starch hydrolyzed by shear enzyme was obviously lower than that of unprocessed starch,and the aging rate of starch after shear treatment was slow according to the decrease of light transmittance coefficient.（5）The sedimentation rate of Castanea henryi starch was higher than that of untreated Castanea henryi starch.（6）The stability of chestnut starch obtained by shear enzymolysis was worse than that of original starch during freezing and thawing.（7）The peak viscosity of the starch prepared by shear enzymolysis was obviously higher than that of the original starch,and its resistance to high temperature was slightly lower than that of the original starch.Therefore,its disintegration value is also higher than that of the original starch,under different temperature conditions,it has better morphology and processability than original starch.（8）Enzyme-hydrolyzed starch is a high e GI food,reaching 92.48.Compared with high gluten wheat core flour,it can raise blood sugar quickly and is easy to be absorbed by human body.（9）The content of crude polysaccharide in the supernatant was increased to 31.2 mg/m L.3.On the basis of traditional bread making,nutritional bread was made by adding chestnut enzymatic hydrolysate.The effects of different contents of Castanea henryi hydrolysate,sugar,yeast and bread improver on the specific volume and comprehensive quality of bread were studied.In this paper,single factor experiment and quadric rotation orthogonal experiment were used to determine the scheme and improve the quality of bread.The best formula of bread was high gluten core wheat flour 100 g,yeast 1.54 g,sugar 4.64 g,egg 8g,milk powder 8 g,fat 8 g,bread improver 0.3 g,salt 1 g,90%chestnut hydrolysate 53 g.The bread prepared with this recipe had moderate volume,good texture index and high sensory evaluation score.The estimated Glycemic index e GI was108.66.