Digestibility of protein and starch from sorghum (Sorghum bicolor) is linked to biochemical and structural features of grain endosperm

Bioconversion of degraded husked sorghum grains to ethanol

“…3b). These results correspond with previously reported ethanol concentrations of 30-35 g/L for P. stipitis fermentation with starch as substrates [23,[31][32][33]. However, S. cerevisiae fermentation with SSV2, KSV8 and KSV3 as substrates yielded 42 g/L, 50 g/L and 45 g/L ethanol, respectively (Fig.…”

“…Although supplementation with Batch-2 enzyme cocktail, that contains additional thermostable amylases and proteases, yielded higher levels of FAN and sugars ( Table 4) the costs of using additional enzymes in this cocktail may have an adverse impact on the overall economics of the process. While amylases further degrade starch to monomeric sugars, proteases breakdown complex protein polymers to simple molecules such as free amino acids and peptone [16,23]. However, no significant increase was observed in concentration level of xylose, this may be due to the lack of exogenous hemicellulase enzymes in either of the prepared enzyme cocktails.…”

“…Generally, proteins are the nitrogenous sources by liberating more sugars [21], while KSV8 control substrate favoured higher proteolytic enzyme activity (Table 4). The significantly higher FAN level of KSV8 mash may largely be attributed to combinations of its relatively higher albumin and globulin protein contents [23]. However, on digestion of the substrates with Batch-1 enzyme cocktails, notable increases in levels of glucose and FAN were observed ( Table 4).…”

“…Finally, SSV2 starch exhibited comparatively different pasting profiles and low setback viscosities. The pasting characteristics of SSV2 may be due to lignin interference during pasting [16,23]. Table 3 shows that SSV2 had significantly higher lignin content than both KSV8 and KSV3 substrates.…”

Effect of popping on sorghum starch digestibility and predicted glycemic index

“…In the corneous endosperm of native sorghum, the nonkafirins (albumins, globulins and glutelins) effectively "glue" the bodies into a matrix surrounding the starch granules. However, sorghum proteins contain a higher proportion of cross-linked fractions of kafirins and are more hydrophobic that explain their higher propensity to form disulphide bonds (Wong et al 2009). Perhaps the disruption of cell wall and damage to these gluing substances make the soluble proteins available for digestion by pepsin to enhance protein digestibility.…”