Proteolytic activities in togwa, a Tanzanian fermented food

• Published in: International journal of food microbiology Vol. 84; no. 1; pp. 1 - 12
• Main Authors: Mugula, J.K., Sørhaug, T., Stepaniak, L.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15-07-2003; Elsevier
• Subjects: Aminopeptidases - metabolism; Biological and medical sciences; Cereal and baking product industries; Chromatography, Liquid; Coculture Techniques; Edible Grain - enzymology; Edible Grain - microbiology; Electrophoresis, Polyacrylamide Gel; Endopeptidases - metabolism; Fermentation; Food Handling - methods; Food industries; Food Microbiology; Fruit and vegetable industries; Fundamental and applied biological sciences. Psychology; Lactic acid bacteria; Lactobacillus - enzymology; Lactobacillus - metabolism; Molecular Weight; Pediococcus - enzymology; Pediococcus - metabolism; Plant Proteins - metabolism; Proteolysis; Saccharomycetales - enzymology; Saccharomycetales - metabolism; Sorghum; Starter cultures; Tanzania; Togwa; Yeasts; Yeasts - enzymology; Yeasts - metabolism; Tanzania; Starter cultures; Yeasts; Sorghum; Lactic acid bacteria; Togwa; Proteolysis; Yeast; Enzyme; Aminopeptidases; Fermented product; Traditional food stuff; Peptidases; Enzymatic activity; Cereal product; Quality; Plant protein; Hydrolases; Cassava
• ISSN: 0168-1605; 1879-3460
• DOI: 10.1016/S0168-1605(02)00387-2

Proteolytic activities were investigated in sorghum-based
togwa prepared by natural fermentation and using starter cultures previously isolated from the native product, i.e.,
Lactobacillus brevis,
Lactobacillus cellobiosus,
Lactobacillus fermentum,
Lactobacillus plantarum,
Pediococcus pentosaceus, and
Issatchenkia orientalis in coculture with either
L. brevis or
L. plantarum.
Both proteinase and aminopeptidase activities were substantially higher in naturally fermented
togwa than in those with starters (14–30%, 12–70%, respectively). A variable but substantial part of the proteinase activity followed the particulate fraction of
togwa; aminopeptidase activity was mainly in that fraction. The breakdown of relatively high molecular mass protein (64 kDa) in
togwa was detected by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE); the products were mainly in the 14–30 kDa range. Reversed-phase fast-protein liquid chromatography (RP-FPLC)-protein/peptide patterns changed during fermentation with some variation between
togwa of different cultures. Supplementation of gruel with malt increased the concentration of total protein [from 9.5% to 11.0% (w/w) on dry weight basis)] and of most of the free amino acids. Fermentation had no effect on total protein content; however, the concentration of most of the amino acids was reduced, except for the proline content that increased. Natural fermentation also increased the concentration of glutamic acid and ornithine. Fermentation by
P. pentosaceus increased aspartic acid, while
L. cellobiosus,
L. fermentum, and
L. brevis in coculture with
I. orientalis increased the concentration of citrulline.