RU2088333C1 - Method for preparing and processing of rice grains - Google Patents

Abstract

FIELD: food-processing industry. SUBSTANCE: method involves removing contaminants from rice grains; treating with vapors of propionic acid for 1-15 min; softening; slightly drying and simultaneously heating rice grains prior to processing for producing rice grout; shelling and polishing to obtain groat. EFFECT: increased efficiency, simplified method and improved quality of product.

Description

 The invention relates to the technology of postharvest storage and processing of rice grains.

 A known method of preparation and processing of rice grains, including cleaning from impurities, drying, treatment with propionic acid in an aerosol state, baking and processing into cereals by peeling and grinding.

 The disadvantages of this method are the preservation in the cereal of propionic acid, the difficulty of peeling and the high consumption of propionic acid.

 The objective of the invention is to eliminate the absorption of propionic acid by the endosperm during the curing process, to facilitate peeling and reduce the consumption of propionic acid.

 This is solved by the fact that in the method of preparing and processing rice grain, including purification from impurities, drying, treatment with propionic acid, curing and processing into cereals by peeling and grinding, according to the invention, the treatment is carried out with propionic acid in a vapor state for 1-15 minutes and drying is carried out with the simultaneous heating of rice grains immediately before processing into cereals.

 This eliminates the ingress of propionic acid into the cereal by reducing or eliminating the precipitation of propionic acid on the grain, which simultaneously reduces its consumption, and facilitate peeling by removing moisture and precipitated on the grain of propionic acid when the husk is peeled from the endosperm.

 The method is implemented as follows.

 Freshly harvested rice grain is cleaned of coarse mechanical and magnetic impurities and treated with vapors of propionic acid for 1-15 minutes, depending on the temperature of rice grain and vapors of propionic acid. If the temperature of the rice grain is higher than or equal to the temperature of the propionic acid vapor during processing, then precipitation of propionic acid on the grain surface does not occur. Otherwise, part of the propionic acid vapor condenses with the release of the heat of condensation and the formation of a thin film of propionic acid on the grain surface. The combined thermal and chemical effects on the microflora allows sterilization of grain in a shorter period of time. At the maximum temperature difference between rice grain and propionic acid, which does not lead to morphological changes in grain tissues, its sterilization time is 1 min, which is confirmed by experimental data. In the absence of condensation of propionic acid vapors on the grain surface, its sterilization time is maximum and equal to 15 minutes.

 The increase in processing time above 15 min is impractical due to the sorption of propionic acid by the grain, which affects the quality of the cereal due to the accumulation of propionic acid in it. The reduction in processing time during the condensation of propionic acid vapors on the grain surface obviously excludes sterilization of the latter and reduces the time for possible curing before processing with a simultaneous deterioration in the quality of the obtained cereals, which is visually determined by the detection of moldy grain during long curing, or leads to a sharp increase in yellow grains in the resulting cereal .

 Sterilized rice grain, regardless of whether propionic acid was condensed on its surface or not, is stored until processing without changing consumer properties from 2 to 6 months.

 The consumption of propionic acid for the conservation of rice grains ranges from 0.01-0.05% by weight of the grain. It depends on sterilization conditions, that is, on the temperature difference between rice grains and propionic acid vapors. The minimum consumption of propionic acid corresponds to the sterilization mode in the absence of condensation of propionic acid on the surface of the grain. At the maximum rate of condensation of propionic acid vapors on the grain surface during sterilization, the consumption of propionic acid corresponds to the upper limit. According to the prototype method, the consumption of propionic acid is twice as high as the above for the proposed method.

 Before processing rice grains into cereals, it is subjected to heat drying. In this treatment, propionic acid adsorbed or condensed by grain is removed together with excess moisture, and the upper layers of the grain, which dry and shrink faster than the inside, that is, peeling waste exfoliates from the endosperm and crack, partially detached from the endosperm even before peeling. Dried grain is processed into groats by peeling and grinding. In the process of peeling, the endosperm, which has a slightly higher humidity, is easily separated from the waste and does not crack. Grinding removes the surface layers of the endosperm containing traces of propionic acid not removed during the drying process. Chemical analysis data indicate the complete absence of propionic acid introduced into the grain during the conservation process according to the proposed method, in the obtained cereal.

 Thus, the proposed method allows to reduce the consumption of propionic acid, to facilitate peeling of the grain and to prevent the accumulation of propionic acid in the resulting cereal.

Claims (1)

 A method of preparing and processing rice grain, including purification from impurities, drying, treatment with propionic acid, baking and processing into cereals by peeling and grinding, characterized in that the treatment is carried out with propionic acid in a vapor state for 1 to 15 minutes, and drying is carried out with simultaneous heating of rice grains immediately before processing into cereals.