The Influence Of Different Processing Technology On Sweetpotato Dietary Fiber Properties

Sweetpotato plays an important role in our country’s economy crop, it has the largest harvest areaand the most production quantity in the world. Sweetpotato residues are major by-product with a largeamount from sweetpotato starch extraction processing, which has not been fully exploited through theages. The effects of dietary fiber are regulating blood lipid, preventing obesity and so on. Researchingand developing functional food which contained dietary fiber has a broad application prospect. Theexperiment took sweetpotato residue as raw material, and optimized the process of dietary fiberextraction respectively through alkali and enzyme extraction method. Then compared the influence ofdifferent processing methods on sweetpotato dietary fiber, analyzed the dietary fiber physicochemicalcharacteristics, functional properties and structural distinction. It also discussed the biscuit qualitywhich added by different levels of sweetpotato dietary fiber. The results are as follows:1. The alkali extraction method of dietary fiber was optimized through single-factor test andorthogonal design test. Results showed that optimal conditions were solid-liquid ratio1:15, time2h,pH12, temperature60℃. The enzyme extraction method of dietary fiber was optimized through thedesign of response surface. Results showed optimal conditions were ultrasonic time11.55min, alphaamylase dosage2940U/g, trypsin dosage107U/g, glucoamylase dosage8280U/g. The yield ofdietary fiber through enmyze method was higher than alkali method with low dissipation. The enzymemethod was selected as the extraction methods of dietary fiber in the subsequent experiment.2. To optimize the processing technology of dietary fiber, the results showed optimal processconditions were: atmospheric pressure cooking time20min, high pressure cooking time25min, whenmicrowave power is640w, microwave time of6min, solid-liquid ratio1:3, microwave cookingtechnology is the best, when32%material moisture, screw speed130r/min, extrusion temperature110℃, extrusion cooking process is the best. Comparing and analyzing the physic-chemical propertiesand structural properties of dietary fiber, the dietary fiber were got thought different cookingtechnologies. Results showed that the dietary fiber after cooking process increased its swelling capacity,water holding capacity, water binding capacity and et al, while its oil holding capacity and fat bindingcapacity were decreased. The analysis of dietary fiber struction showed that process of cooking make itssurface cellular structure fracture, but has little influence on its chemical component. Comprehensiveindicators, in four kinds of cooking methods, extrusion cooking obtained the optimal dietary fiberquality.3. According to the experiment of biscuit quality, following information were got: when4%and6%sweetpotato dietary fiber were added in the dough, the biscuits were better in sensory acceptability,physical properties and texture characterisitics. With this dosage, biscuit has maximum spread factorand uniform color, its hardness and chewiness properties were actually more accepting by people.