Reference : Effect of the use of dilute alkaline prior to Bacillus subtilis-based biocontrol stee...
Scientific journals : Article
Life sciences : Food science
Effect of the use of dilute alkaline prior to Bacillus subtilis-based biocontrol steeping and germination conditions on red sorghum malt β-glucanase activities and residual β-glucans
Bwanganga Tawaba, Jean-Claude mailto [Université de Liège - ULiège > > > Doct. sc. agro. & ingé. biol.]
Destain, Jacqueline mailto [Université de Liège - ULiège > Chimie et bio-industries > Bio-industries >]
Malumba Kamba, Paul mailto [Université de Liège - ULiège > Chimie et bio-industries > Labo. d'Ingénierie des procédés agro-alim. >]
Bera, François mailto [Université de Liège - ULiège > Chimie et bio-industries > Science des alim. et formul. >]
Thonart, Philippe mailto [Université de Liège - ULiège > Département des sciences de la vie > Biochimie et microbiologie industrielles >]
Journal of Cereal Science
Academic Press
Yes (verified by ORBi)
United Kingdom
[en] Dilute alkaline, Bacillus subtilis biocontrol ; β-glucans and β-glucanase ; red sorghum malting
[en] Malting is the ideal stage to deal with β-glucans. Their hydrolysis is very important as the diffusion of both hormones and hydrolytic enzymes in the endosperm of germinated grain depend on it. A high malt β-glucanase activity is not a guarantee of an extensive hydrolysis of β-glucans. When Bacillus subtilis is used to control mould growth, red sorghum malt β-glucanase activity (measured using carboxymethylcellulose as the substrate) was improved without significantly affecting the hydrolysis of malt β-glucans. Thus, in order to reduce the residual β-glucans content, soaking in 0.2% NaOH was combined with a biocontrol. Soaking in 0.2% NaOH is recognized as capable of improving grain hydration by opening-up the endosperm cell walls. The combined use of 0.2% NaOH with Bacillus subtilis-based biocontrol treatments during red sorghum malting, leads to malt with increased β-glucanase activity and a significant reduction of residual β-glucans when compared with the 16 h biocontrol steeping without prior steeping in 0.2% NaOH. β-glucanase activity increases with increased germination temperature and time while, conversely, the residual β-glucans content of the malts decreases. Indeed, while the level of β-glucanase was not vastly different between the malts obtained after steeping in distilled water and those obtained after 8 h steeping in 0.2% NaOH followed by 8 h resteeping in distilled water (NaOH+H2O treatment), their residual β-glucans levels differ significantly. Bacillus subtilis-based treatment leads to malt with improved β-(1-3)- and β-(1-4)-glucanase activities without significantly improved malt β-(1-3),(1-4)-glucanase activity. While malts obtained after 84 h germination weren’t significantly different in terms of malt β-(1-3),(1-4)-glucanase activities for all steeping treatments, the use of 0.2% NaOH steeping prior to resteeping led to malts with improved β-glucans content. Combining the steeping in dilute alkaline and biocontrol enables taking advantage of the dilute alkaline effect on residual β-glucans content, due probably to the opening-up the cell walls and the improvement of water uptake, and that of the biocontrol (improvement of β-glucanase synthesis).
Université de Liège
Researchers ; Professionals ; Students

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