Effects Of Different Hydrocolloids On The Properties Of Chestnut Starch Gel And Vermicelli Formation

Chestnut,rich in nutrients,has biological activities such as preventing high blood pressure,osteoporosis,and delaying aging,and has wide application prospects in the field of food.Chestnut starch is the most important ingredient in chestnut,which is easy to retrogradation when heated,and the heating is unstable,which limits its application range.Therefore,starch modification is necessary during starch processing.Chemical modification will have chemical residues during modification,while enzymatic modification is expensive,and physical modification is widely used because of its simplicity and convenience.Studies have shown that hydrocolloids can significantly improve the properties of starch and expand its application range.However,most of them are modified with a single hydrocolloid,and most of them focus on the modification of common grain starch.The improvement of the physicochemical properties of chestnut starch is unknown.Therefore,in this study,chestnut starch was used as the research object to explore the effects of different hydrocolloids(Mesona chinensis Benth polysaccharide carboxymethyl chitosan,xanthan gum,sodium alginate)on starch gelatinization,rheology,and its structural properties,and on this basis,combined with dry heat treatment to explore its effects on the gelatinization,structure and digestibility properties of chestnut starch,and added hydrocolloids as additives to the preparation of vermicelli to evaluate its effect on the quality of vermicelli.The main findings are as follows:(1)Chestnut starch was prepared by water extraction,and the basic physicochemical properties of chestnut starch were explored.It was found that the starch content of chestnut starch was 98.09%,the amylose content was 16.23%,and the protein content was 1.3%.After high temperature treatment,the starch showed a higher degree of swelling.Scanning electron microscope results also showed that starch was in an irregular state.(2)The effects of Mesona chinensis Benth polysaccharide on the gelatinization,rheology and microstructure properties of chestnut starch were studied.It was found that the addition of Mesona chinensis Benth polysaccharide increased the pasting viscosity and viscoelasticity of chestnut starch.The addition of Mesona chinensis Benth polysaccharide significantly promoted the formation of chestnut starch gel,and promoted the transition of water in the sample from free state to bound state,and reduced the spin-spin relaxation time value of the sample.The infrared spectrum of the compound system showed similar peak shapes,which indicated that there was no new covalent bond between starch and Mesona chinensis Benth polysaccharide,and the main force was hydrogen bond.In addition,the addition of Mesona chinensis Benth polysaccharide also improved the thermal stability of starch.X-ray diffraction results showed that the ungelatinized chestnut starch showed a typical C-type crystal structure,while the original crystal structure was destroyed after gelatinization,showing an amorphous state.The addition of Mesona chinensis Benth polysaccharide did not change this amorphous state.At the same time,the results of scanning electron microscopy showed that the addition of Mesona chinensis Benth polysaccharide promoted the formation of a regular network structure.This will be helpful for improving starch properties and can promote the development of starch-based foods.(3)The effects of three different hydrocolloids(carboxymethyl chitosan,xanthan gum and sodium alginate)on the gelatinization,rheology,and structural properties of chestnut starch were compared.It was showed that the addition of xanthan gum and sodium alginate significantly increased the pasting viscosity,viscoelasticity,gel strength and hardness of starch,and promote the formation of gel.And it can reduce the spin-spin relaxation time value,so that the free water in the system changes to the bound water.But with the same amount of xanthan gum and sodium alginate added,the effect of xanthan gum was more obvious.However,the addition of carboxymethyl chitosan showed an opposite decreasing trend,but like xanthan gum and sodium alginate,it cannot form covalent bonding with starch during gelatinization,and did not generate new functional groups.The crystal structure disappeared after gelatinization.However,the addition of carboxymethyl chitosan increased the spin-spin relaxation time value of the chestnut starch gel,showing a porous and loose honeycomb structure.This will provide some theoretical basis for the modification of chestnut starch by hydrocolloids,and also provide theoretical references for hydrocolloids to improve other starches.(4)The effects of the combination of xanthan gum and dry heat treatment on the gelatinization,structure and functional properties of chestnut starch were explored.The results showed that the gelatinization viscosity of chestnut starch after dry heat treatment,including peak viscosity,trough viscosity,final viscosity and setback viscosity,viscoelasticity,gel strength and hardness,all decreased,which were negatively correlated with treatment time.Dry heat treatment is detrimental to gel formation,whereas xanthan gum promotes the formation of gel.X-ray diffraction results indicated that gelatinization would destroy the crystal structure of chestnut starch gel.Scanning electron microscopy showed that the structure of chestnut starch gel became homogeneous after dry heat treatment and xanthan gum combined treatment.Dry heat treatment and xanthan gum had a synergistic effect on reducing in vitro digestibility,and the content of resistant starch was increased to 64.36%through treatment,which can provide ideas for the preparation of resistant starch and the development of low GI food.(5)Based on the good improvement properties of several hydrocolloids on starch,the effects of four kinds of hydrocolloids,namely Mesona chinensis Benth polysaccharide,carboxymethyl chitosan,xanthan gum and sodium alginate were investigated.And Fourier Transform Infrared,scanning electron microscope,X-ray diffraction,elongation at break were characterized and sensory evaluation were carried out,which showed that compared with pure vermicelli,the addition of hydrocolloids can reduce the elongation at break of vermicelli,and present a smooth structure,among which the effect of xanthan gum was the most significant.Through the sensory evaluation score,it is obtained that the addition of xanthan gum has the highest score,followed by carboxymethyl chitosan.This research shows that hydrocolloids can improve the characteristics of vermicelli and can improve the quality of vermicelli,which will provide broad application prospects for the production of vermicelli products and the development of starch-based foods.