| Edible natural pigment is more and more popular because of its safety and reliability,natural color and bioactive ingredients.Castanea henryi shell is a by-product of processing of Castanea henryi,which contains certain brown pigment,which is used for coloring brown food such as cola,chocolate,wine and so on.Therefore,the pigment has high value of development and utilization and application prospect.In this study,using Jianou Castanea henryi shell as raw material,the extraction conditions of pigment from Castanea henryi shell by ultrasonic-assisted extraction were optimized by response surface method,and the crude pigment was purified by macroporous adsorption resin.The antioxidant activity of crude and purified pigment from Castanea henryi shell in vitro and their antioxidation ability to lard and other oils were studied.The main contents and conclusions were as follows:(1)Using dried Castanea henryi shell powder as raw material,ultrasonic-assisted sodium carbonate extraction was used to extract the pigment from Castanea henryi shell.Based on the single factor experiment,ultrasonic time,ultrasonic temperature,ultrasonic power was selected as independent variable,and extraction rate was as response value.By using Box-Behnken center combination design of response surface,the effects of various factors and their interactions on the extraction of pigment from Castanea henryi shell were studied,and the prediction model of quadratic polynomial regression equation was obtained.The optimum extraction technology was determined as follows:ultrasonic time 47 min,ultrasonic temperature 82 ?,ultrasonic power 450 W.Under these conditions,the actual extraction rate of pigment from Castanea henryi shell was 38.41%,which was close to the predicted value of 39.18%.Hence,the prediction model had some practical significance.(2)Seven types of macroporous resin(XAD-7?D4020?D101?DA-201?NKA-9?X-5?AB-8)were comparatively studied for their adsorption and desorption effects on crudely extracted Castanea henryi shell pigment in this paper.The optimum macroporous resin was selected and the optimal dynamic adsorption technological conditions were investigated by single factor experiment and orthogonal experiment.The results showed that D101 macroporous resin had better adsorption and desorption effect on the crudely extracted Castanea henryi shell pigment,and the optimum process conditions for dynamic adsorption and purification of pigment were as follows:adsorption column diameter-height ratio 1:10,sample flow rate 1.5 mL/min,sample concentration 0.100 mg/mL.Using 80%ethanol solution as eluant,desorption rate was the highest when the elution flow rate was 1.0 mL/min.Under the above purification conditions,the color value of Castanea henryi shell pigment was increased from 31.2 to 74.3,and the purity increased by 1.38 times.Purified pigment was easily dissolved and its solution was crimson brown,clear and bright,and stable.(3)Taking Vc as positive control,the reduction ability,the clearance effect on ·OH,O2· and DPPH· and the antioxidation effect on lard and other oils of crude and purified pigment from Castanea henryi shell was studied.The results showed that the crude and purified pigment from Castanea henryi shell had a certain reductio1 capacity of Fe3+,and the reductive power of purified pigment was higher than that of crude pigment at the same concentration.The scavenging rate of crude pigment,purified pigment and Vc to · OH and DPPH · was positively correlated with the concentration.At the same concentration,the scavenging rate of purified pigment to DPPH· was higher than that of crude pigment and Vc,and the scavenging rate of purified pigment to · OH was higher than that of crude pigment.At the concentration of 0.5?2 mg/mL,the scavenging rate of purified pigment to ·OH was higher than that of Vc.The crude and purified pigment also had a certain ability of scavenging O2-,purified pigment was obviously superior to the crude pigment,but the scavenging effect decreased with the increase of concentration.The crude and purified pigment had some antioxidant effect on lard,peanut oil and soybean oil,and at the pigment concentration of 0.02%,0.01%and 0.01%exhibited the greatest antioxidant effect for lard,peanut oil and soybean oil.At the same dosage,the antioxidant effect of crude and purified pigment was weaker than that of TBHQ,BHT and Vc,but the antioxidant effect of purified pigment was greater than that of crude pigment. |
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