Isolation And Charaterization Of Hull-less Barley Starches

This paper studied on the starch extraction process from hull-less barley (HB)rice and flour, further study of HB starch physicochemical properties, including: characteristics of starch granules, starch paste characteristics and starch digestion characteristics.Factors that had influenced on the yield of HB starch were mainly considered, including the solvent-water ratio, soaking time, homogenization speed, and cellulase and xylanase enzyme conditions (the amount of enzyme, hydrolysis time, hydrolysis temperature and pH), basis on the single factor experiments, technological parameters of the solvent-water ratio is 1:5, soaking time 24h, homogeneous speed 10000r/min, compared the role of two enzymes effect, The effect of cellulase was batter than that of xylanase. Identified the optimum conditions of cellulase enzyme for: hydrolysis time was 2h, pH 4.5, the amount of enzyme was 0.3%, hydrolysis temperature is 50℃, In these optimum conditions, the yield of starch was 51.03%. On the basis of starch extraction process from HB rice, the starch extraction process from HB flour was determined on, the yield of starch extraction from HB flour was lower than that of HB rice.After obtaining a HB starch extraction process, and extracted HB starch from three types of barley flour (Linzhoul48, Beiqing6, Kunlun6) and one type of HB rice(Zangqing320), and the physicochemical properties of four kinds of HB starches were studied, the study found:There were differences in the basic components of the different varieties of HB starch. Starch from HB rice had higher rate of damage starches, four kinds of HB starch were normal HB starch; The particle size of HB starches were from 2μm to 40μm, there were mainly large granule starch in HB barley starch, the surface of starches granule were smooth, shape of mostly HB starches were flat spherical and oval-shaped, the HB starch also contained a certain amount of small granule starches. The average particle diameter of starches granule starches were from17.49μm to 18.13μm. the starch of HB and wheat all displayed typical A-type X-ray diffraction patterns. The transparency of HB starch paste and wheat starch paste decreased with storage time, but the transparency of starch paste rapid decline at first, and then tends to slow the decline of transparency limits; The solubility and swelling power of all starches paste increased with the temperature; In general, the solubility of HB starch was positively correlated with amylose content, swelling power was negatively correlated with amylose content, the solubility and swelling power of starch was also restricted by the size of starch granules; the freeze-thaw stability of HB starch was negatively correlated with amylose content; The peak viscosity of HB starch was negatively correlated with solubility, pasting temperature was negatively correlated with swelling power. Zang-qing320 had the highest peak viscosity, lowest value of breakdown, the best of hot paste stability, but the pasting temperature was highest; In the liquefaction, the dextrose equivalent(DE) of HB starch was from 17.55 to19.33; After saccharification, DE of HB starch was from 80.04 to90.14; The difference in DE value of HB starch was because of grain size distribution of starch and damaged starch content; the trend of paste transparency, solubility and swelling power of HB starch and wheat starch was consistent, but there were differences in the rate of change; The thermal stability of HB starch paste was worse than wheat starch paste, HB starch was easy to aging; The degree of HB starch hydrolysis was lower than wheat starch.