Study On Preparation Of Enzymatic Helix Dextrin And Its Application

Deep processing is an important method to increase value of starch and provide different starch derivatives for industrial raw material. Based on the native starch as material, using the enzyme technology, the present researches mainly focus on preparing of the enzymatic helix dextrin（HD） with complexation capability. The results showed that the inclusion complexation capability of four kinds of starch was cassava starch, potato starch, corn starch, waxy corn starch from high to low in turn. A series of HD with different molecular weight distribution was got with the method of alcohol sink. DP decreased with the alcohol concentration increasing and the lower DP value of HD had the stronger complexing ability. The highest inclusion complexation capability HD was applied as an inclusion carrier of quercetin. The main results were as follows:The effect of reaction parameters such as reaction time, reaction temperature, reaction pH and addition amount of quercetin solution on the quercetin content and conversion rate was investigated. The results showed that the optimal conditions for preparing HD/quercetin complexes were: reaction time 4 h, reaction temperature 60 ℃, reaction pH 6.0 and the addition amount of quercetin solution 5%（w/w）. The content and inclusion rate of quercetin prepared under the optimal conditions were 38.43 mg/g and 82.80%, respectively. The process conditions were optimized by using the response surface method. The response surface results showed that the optimal conditions for preparing HD/quercetin complexes were: reaction time 4.5 h, reaction temperature 64 ℃, reaction pH 6.5 and the addition amount of quercetin solution 5%（w/w）. The content and inclusion rate of quercetin prepared under the optimal conditions were 41.57 mg/g and 87.32%, respectively.The formation, thermodynamic property and appearance of HD/quercetin inclusion complexes were confirmed by the results of FT-IR、XRD、¹³C CP/MAS NMR、DSC、DTG、SEM and CLSM. The results of FT-IR spectrum suggested that HD/quercetin inclusion complexes had a C-O stretch vibration absorption spectra at 1264 cm-1,which indicated that HD really reacted with quercetin. XRD results showed that HD/quercetin inclusion complexe overall crystal size became smaller with V crystal structure as the similar amylose inclusion complexes. The results of 13 C CP/MAS NMR spectrum suggested that the C-4 absorption peak of HD/quercetin inclusion complexes was weaken, which indicated the HD reacted with quercetin in the combination of chemical bond. The results of DSC curve indicated that the HD/quercetin inclusion complexes had a new material melting peak at 314.8 ℃, the melting peak of quercetin and the decomposition peak of HD were disappeared. DTG curves showed that weight loss of HD/quercetin inclusion complexes was 18.07% higher than mixture at the process of degradation. The results of SEM photos showed that the surface of HD/quercetin inclusion complexes was smooth and neat with edges; spherical particles were more apparent, quercetin fiber strips were weaken with disappearance, rough surface morphology of HD was improved. CLSM showed the pictures of HD/quercetin inclusion complexes could be observed with the red and green fluorescent material, red part existed in the middle of green fluorescence. These results suggested that HD really reacted with quercetin and the quercetin presented in the cavity of the HD.The solubility, hygroscopicity, vitro digestibility, degradability, stability, oxidation resistance and releasing characteristics of HD/quercetin inclusion complexes were studied. The solubility of quercetin in HD/quercetin inclusion complexes was higher than the sample without quercetin. HD/quercetin inclusion complexes presented a strong resistance to digestion. The thermal stability, acid or alkali stability, light stability and oxygenin stability of HD/quercetin inclusion complexes were improved. The results of degradability experiments showed that HD/quercetin inclusion complexes were mainly released in the small intestine.