Effect of decortication and protease treatment on physicochemical and functional characteristics of red sorghum (Sorghum bicolor) and yellow maize (Zea maiz) starches

Abstract

Sorghum is a cereal from which starch is not commonly isolated; however, its functional characteristics are similar to other cereal starches such as maize. Red sorghum kernels were processed with and without mechanical decortication followed by steeping in a sodium bisulfite solution to 50% solids, with and without a commercial protease following by wet milling. For comparison purposes, yellow maize kernels were also protease treated and wet milled. Results indicate a significant increase on starch yield in both cereals when the decorticated sorghum or maize flours were treated with the protease from 59.11 to 63.21% and 43.59 to 58.89%, as well as purity from 96.52 to 98.45 and 95.95 to 98.75% for maize and sorghum, respectively. The combination of mechanical decortication and protease treatments increase starch gelatinization temperature from 77.5 to 81.5°C, as well as a decrease on the final viscosity, indicating that the protein associated to the starch granules restricted swelling and amylose leaching during pasting. Isolated starch from decorticated sorghum kernels was lighter in color due to the removal of pericarp rich in phenolics. The mechanical decortication prior to wet milling presented the advantage of the removal of stable sorghum bran that contains an array of nutraceutical and antioxidant compounds, whereas the use of the proposed decortication followed by enzyme treatment promote higher yields of refined starch.

Sugary Endosperm is Modulated by Starch Branching Enzyme IIa in Rice (Oryza sativa L.)

“…The reason for the phenotypic similarity between su-1 mutant by Nakamura et al (1997) and sug-h mutant in this study remains to be comparatively studied. Recently, a rice novel endosperm mutant, named as sugary-2 , was reported (Nakagami et al 2016), in which the results on the activity of BE in the sugary-2 mutant was unlike the sug-h mutant, indicating that the sugary-2 mutant was different from the sug-h mutant.…”

“…The sug-h mutant was induced by N-methyl-N-nitrosourea (MNU) treatment on the Korean japonica cultivar Hwacheong (Koh and Heu 1994; The sug-2 was renamed in this study as sug-h to avoid confusion with Nakagami et al (2016)). The F 2 population was derived from a cross between the sug-h mutant and M.23.…”

“…Grains of the sug-h mutant have better quality for subsequent processing and higher yield than sug-1 . In addition, palatability, protein and amylose content which are crucial for breeding were increased in sug-h mutant (Yoon et al 2009; sug-2 was renamed as sug-h to avoid confusion with Nakagami et al (2016)). Therefore, sug-h mutants could be valuable for practical applications and nutritional aspects.…”

Methods for Extracting Cereal Starches from Different Sources: A Review

“…Chew‐Guevara proposed a method in order to increase starch yield and recovery performance from red sorghum kernels subjected to mechanical decortication and with the use of a protease during the sulfur dioxide wet‐milling process. A significant increase on starch yield (from 59.11% to 63.21%) and the starch purity (from 96.52% to 98.45%) were observed when the decorticated sorghum flour was treated with the protease.…”

Comparison of Isolation Methods and Physicochemical Characteristics of Starches Isolated from Red and White Sorghum Hybrids

“…These results indicate that the maceration with sulfite/lactic acid solution and the combination of maceration with protein hydrolysis promoted the release of starch granules from the protein matrix, improving yield and starch recovery. Chew-Guevara et al [10] evaluated starch isolation with and without protease hydrolysis from decorticated red sorghum. They reported yields and recoveries of 49.12% and www.advancedsciencenews.com www.starch-journal.com 73.36% for the isolation method without proteases (24 h steeping at 50°C), which were similar than the values found in our study.…”