STORAGE STABILITY OF SORGHUM FLOUR PRODUCED BY DIFFERENT METHODS

HIPCZG

Abstract

The effect of the method of sorghum flour production on its storage stability, assessed by moisture content, acidity by beaten-up flour and water, and acidity by aqueous-alcoholic extract, was studied. The following methods for increasing the storage stability of flour were investigated: partial removal of the hulls and germ during grain hulling and polishing, and hydrothermal treatment (HTT) of sorghum grain during its preparation for hulling. Two HTT methods were used: with intensive moistening under vacuum, grain resting and drying, and with grain steaming and drying. In addition, flour was produced from sorghum grain that was not subjected to HTT and did not undergo the hulling and polishing operation (whole grain flour). The grain and kernel were ground in a laboratory hammer mill with a built-in sieve No. 08. Freshly ground sorghum flour was sent for storage at a relative air humidity of 65±0.1% and a temperature of 20±0.5 and 40±1 ℃. The flour was stored in textile (cotton) bags and polyethylene packages.

It was found that the method for obtaining sorghum flour had virtually no effect on the equilibrium moisture content of sorghum flour stored at a constant temperature; the inclusion of hulling-polishing and hydrothermal treatment of grain in the technological scheme for preparing sorghum for grinding stabilized the properties of sorghum flour during storage: the growth of titratable acidity slowed down both for the acidity by beaten-up flour and water and for the acidity by aqueous-alcoholic extract; the best shelf life according to the studied quality indicators was noted for flour from grain that underwent HTT with steaming, followed by flour from grain that underwent HTT with vacuum humidification, then flour from hulled but not HTT-treated grain; whole grain flour had the lowest shelf life; packaging in polyethylene bags showed better preservation of sorghum flour compared to packaging in textile bags.