| Barley starch were isolated by wet milling method from seven kinds of barley varieties and theirgranule characteristics, pasting, gel texture and thermal properties were investigated. And barley RS3hadbeen prepared by heat-moisture treatment combined with enzyme. The main conclusions are as follows:(1) The average total starch, amylose and amylopectin content of seven barley varieties were95.78±2.33%,25.30±2.02%, and70.24±2.31%, respectively.The barley starch granules appeared to be smooth and displayed a disk, tabular or oval shape with themean percent of surface area, average surface and volume weighted diameters were0.36±0.08%,17.35±2.32m and20.21±0.87m, respectively. There existed A-and B-starch granules in barley starch.All starch granules exhibited a typical “Maltese cross” under polarized light, most of cross appearedcross-shaped, with a few X-shaped. The center of the cross is at the hilum, which communicated with thesurface of microchannels. The average releative crystallinity of barley starch was22.81±0.12%, and thecrystalline pattern was typically “A” type.Both solubility and swelling power increased with the temperature risen, and mean pastingtemperature was58.05±11.70averagely. The average peak viscosity, peak time, trough viscosity, finalviscosity, breakdown, setback and retrogradation volume of starch paste was272.55±18.93RVU,6.580.16min,213.06±17.66RVU,286.39±38.50RVU,63.57±14.90RVU,80.06±21.85RVU and18.88~22.62mL/100mL, individually. The thermal properties of barley starch including T0, Tp, Tc, Trand H was56.28±1.42,59.48±1.48,13.84±2.05and9.08±0.85J/g, respectively.(2) The effects of additive treatment on barley starch gelatinization viscosity characteristics weresignificant, which differed from different kinds of additive and barley. In general, negative effects ofmonoglyceride and sodium stearoyl lactylate on onset gelatinization temperature were observed, but effectsof xanthan gum, sodium alginate tech grade and alkaline condition on gelatinization temperature werepositive. Sodium stearoyl lactylate positively correlated to both peak viscosity and setback, Sodiumchloride had a negative effect on setback, while the effect of xanthan gum was positive; there were positiveeffects on peak viscosity, breakdown and setback of acid and alkali conditions.(3) The effect of addictives on barley starch gel differed from different kinds of additives and barleyvarieties. There was little difference in effects of sucrose or sodium chloride on starch gel springness andcohesiveness; the effects on gel hardness, adhesivenss, springness, resilience, cohesiveness and chewinessof starch type zangqing25, kunlun12, zangqing8were significantly different, and the difference of effects on other gel texture characteristics was not obvious. Significant difference could be seen between effects ofcalcium propionate, potassium sorbate and acidic conditions on gel hardness and chewiness of zangqing148and beiqing6, among three addictives treatment, acidic conditions had an obvious effect on starch geladhesiveness of beiqing6and zangqing320.(4) Fat and protein components in barley flour had a certain impact on RS3preparation. Albumin,globulin and gluten played a positive role in RS3preparation, while gliadin, residue protein and fat effectednegatively. With the use of pullulanase, the optimum reaction parameters of preparation process for was asfollows: barley flour content being20%, dosage of pullulanase enzyme being1.2PUN/g, the engmoysistemperature and time of enzyme being10h and40, then the content of RS3was4.13%, the content ofRS3increased124.24%after removing gliadin under these conditions. |
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