Intensification of process of water-thermal treatment of wheat grain before bread flour milling

摘要

Water-thermal grain treatment in flour-milling processing is enough a passive and long-term stage that iscaused by the anatomical constitution and properties of wheat grain. Therefore large containers are necessaryfor water-thermal treatment (WTT). Nowadays the concept of quick WTT of grain is implemented by manytechnologies which allow to reduce considerably the duration of WTT, to balance the productivity ofpreparatory and milling sections, to vary a batch of wheat with the characteristics necessary to make the kindof flour immediately in a stream, to reduce floor spaces etc.The purpose of our research is to work out a new way of the intensive WTT hastening, which means wheatgrain treatment by wide interval acoustical waves (from 1 to hundreds kHz) in the conditions of the reducedpressure over a grain surface.The influence of the new way of grain treatment was defined by the study of grain processing properties:flour-milling and baking properties. The grain hardness at axial compression, grain swelling degree, the yieldintermediate milling products, the yield of flour and its whiteness, milling process energy were studied forthe flour-milling properties characteristic. To identify grain baking properties the dough physical propertieswere studied using the farinograph, the alveograph. Besides the quantity and quality of gluten, asedimentation index, amylolytic transformations in grain were studied with the amylograph and "Fallingnumber" device. Also it was carried out a trial laboratory baking to understand how the new way of the wheatgrain WTT influences the flour and its final products quality.The variation factors of the new WTT process are impulse power, pressure index, treatment duration which isdirectly bound to the quantity of pulsing oscillations. The WTT was carried out in the pneumopulsing device.A grain moistening operation follows the removal of superfluous humidity from grain before first breakerrolls.While researching approximate variation intervals of the major parameters have been defined. It is revealed,that treatment effectiveness raises under high rarefaction conditions. And the impulse quantity, which isnecessary for preparing processing properties of grain to optimum indexes before the milling process,depends on grain vitreousness: the more is this index, the longer is grain treatment. Some grain indexes afterthe new WTT at certain parameters are equal to the appropriate confirming indexes of grain which wassubjected to traditional cold WTT. Some indexes surpass control values, for example, flour strength raises alittle.The intensive way of effect on wheat grain by acoustical waves under vacuum conditions allows to reducethe duration of soaking of wheat grain in water to several minutes and to improve some indexes of grain andflour.