The Effect Of Hydrolysis On The Adsorption Properties Of Starch

As an adsorbent,starch is widely used in various fields due to its low price,wide source,and natural harmlessness.However,the ability of the original starch to absorb cannot meet the needs of the market,so it is necessary to systematically modify the starch.Porous starch is a new ideal adsorbent.In this paper,maize starch was used as raw material to prepare maize porous starch by citric acid and α-amylase hydrolysis.The effects of preparation conditions on the water absorption,oil absorption,and the amount of tartrazine absorbed by porous starch were studied.In the research,the citric acid was used to treat starch.The effects of citric acid concentration,hydrolysis time,and hydrolysis temperature on the water absorption,oil absorption,and the amount of tartrazine absorbed by the porous starch were investigated.The optimum preparation process parameters were determined by Orthogonal experiment,according to the absorbability of each kind of material.The water absorption rate was used as the performance indexto obtain the optimized process parameters: reaction temperature 45°C,reaction time 5 h,citric acid concentration 83.3 g/L,and water absorption rate 70%.The oil absorption rate was used as the performance index to obtain the optimized process parameters:the reaction temperature 45 °C,the citric acid concentration 83.3 g/L,the reaction time 5 h,and the oil absorption rate detected as 17%.The optimum process parameters were obtained with the amount of tartrazine as the performance index.The reaction temperature was 50 °C,the reaction time was 3 h,the citric acid concentration was 50.0g/L,and the absorption of tartrazine was 1.470 mg/g.The porous starch was prepared by α-amylase hydrolysis,and then the effects of enzyme dosage,hydrolysis time,hydrolysis temperature,and pH on the water absorption,oil absorption,and the adsorption of tartrazine were investigated.The optimum hydrolysis conditions were determined by orthogonal test with adsorption energy as the index.The water absorption rate was used as the performance index and the optimized process parameters were obtained.When the reaction temperature was 50 °C and the reaction time was 3 hours,the pH was 6.5,the α-amylase dosage was 4 g,and the water absorption rate was 95%.The oil absorption rate was used as the performance index to obtain the optimized process parameters:the reaction temperature 50 °C,the reaction time 4 h,the pH was 6.5,and the α-amylase dosage was 4 g,and the oil absorption rate detected as 38%.The optimum process parameters were obtained with the amount of tartrazine as the performance index.The reaction temperature was 50 °C,the reaction time was 3 h,the pH was 6.5,and the amount of α-amylase was 4 g,and the absorption of tartrazine was 1.408 mg/g.The results of the preparation of porous starch from acid-hydrolyzed starch and enzymolyzed starch were studied.The prepared porous starch was found to have increased starch adsorption due to an increase in pore size,an increase in the number of pores,and an increase in the depth of the pores.By SEM observation,the pore distribution formed by citric acid hydrolyzed starch has randomness and uncertainty.Alpha-amylase hydrolyzed starch formed even holes.The damage of citric acid hydrolysis to the starch grain structure was relatively mild than that of the control,with random pore formation position,relatively small number of pore formation,relatively small pore size;faster enzymatic hydrolysis rate,the complete pore formation,deeper pores,forming basically similar pore shape.This was also the reason why porous starch prepared by enzymatic hydrolysis had stronger adsorption than porous starch prepared by acid hydrolysis.