Journal de la transformation et de la technologie des aliments

Abstrait

Evaluating Physicochemical and Rheological Characteristics and Microbial Community Dynamics during the Natural Fermentation of Cassava Starch

Karine H Rebouças, Laidson P Gomes, Analy MO Leite, Thais M Uekane, Claudia M de Rezende, Maria BT Inês, Eveline L Almeida, Eduardo M Del Aguila and Vânia MF Paschoalin

The traditional fermentation of cassava starch was investigated by a polyphasic approach combining (i) microbial community identification using conventional and molecular techniques, (ii) analyses of organic acids, volatile compounds, fermentation products and spin-lattice relation time and (iii) evaluation of technological properties, such as pasting properties, water absorption and water solubility indexes. Cassava fermentation microbiota was dominated by bacteria and yeasts genera. Bacteria genera include Lactobacillus, Leuconostoc, Lactococcus and Enterococcus. Lactobacillus was the prevalent genera responsible for the acidification of cassava fermentation by the production of organic acids and also aromatic compounds. Yeast community was dynamically adjusted through the cassava fermentation Pichia kudriavzevii and Issatchenkia orientalis were succeeded by Geotrichum candidum, Clavispora lusitaniae and Rhodotorula mucilaginosa. Candida rugosa, C. pararugosa, C. akabenensis, Cryptococcus albidus, Neurospora crassa and N. intermedia were found exclusively in sour cassava. The acidification of sour cassava was due to the production of acetic, lactic and succinic acids. Volatile compounds, including aliphatic and aromatic hydrocarbons, esters and terpenes contribute to the aroma and correspond to 23% of compounds found after fermentation and sun-drying treatment. The acidification and fermentation process reduced the peak viscosity, paste viscosity, breakdown viscosity and set back viscosity in cassava starch. Solid-state NMR relaxometry measures were associated to the expansion ability and indicated that the fermented and sun-dried products were more inclined to expansion. Loaf expansion ability and pasting temperatures were increased in sour cassava (fermented and sun-dried). The results showed here should be useful to standardize the manufacturing of cassava starch in Brazil, providing homogeneous and high quality products.