Fermentation and enzyme treatments for sorghum

ABSTRACT

Sorghum (Sorghum bicolor Moench) is the fifth most produced cereal worldwide. However, some varieties of this cereal contain antinutritional factors, such as tannins and phytate that may form stable complexes with proteins and minerals which decreases digestibility and nutritional value. The present study sought to diminish antinutritional tannins and phytate present in sorghum grains. Three different treatments were studied for that purpose, using enzymes tannase (945 U/Kg sorghum), phytase (2640 U/Kg sorghum) and Paecilomyces variotii (1.6 X 10(7) spores/mL); A) Tannase, phytase and Paecilomyces variotii, during 5 and 10 days; B) An innovative blend made of tanase and phytase for 5 days followed by a Pv increase for 5 more days; C) a third treatment where the reversed order of B was used starting with Pv for 5 days and then the blend of tannase and phytase for 5 more days. The results have shown that on average the three treatments were able to reduce total phenols and both hydrolysable and condensed tannins by 40.6, 38.92 and 58.00 %, respectively. Phytase increased the amount of available inorganic phosphorous, on the average by 78.3 %. The most promising results concerning tannins and phytate decreases were obtained by the enzymes combination of tannase and phytase. The three treatments have shown effective on diminishing tannin and phytate contents in sorghum flour which leads us to affirm that the proposed treatments can be used to increase the nutritive value of sorghum grains destined for either animal feeds or human nutrition.