Improvement of Garri Quality by the Inoculation of Microorganisms into Cassava Mash

Abstract

Lactobacillus delbruckii, Lactobacillus coryneformis, and a Saccharomyces sp., previously found among 214 isolates to be the highest producers of linamarase, amylase, and lysine were inoculated separately or mixed into cassava mash and fermented with, or without dewatering, for 24, 48, 72, 96 and 120 h. At the end of the fermentation period, the mash was converted to garri by heating over a gas burner. The mash and the garri resulting from it were assessed for lysine and residual cyanide, while the garri was also studied for its organoleptic properties. The inoculation of the microorganisms into cassava mash produced a sharp drop in the cyanide content of the mash, particularly when the mixture of organisms was inoculated into undewatered cassava mash rather the single organisms. After 24 h, while the cyanide content of the control (uninoculated mash) mash was 3.06mg/g in the dewatered mash, and 4.24mg/g in the undewatered mash, the inoculation of a mixture of the three organisms caused the cyanide content in the inoculated mashes to drop by 150% to 1.96mg/g (dewatered mash) and by 300% to 1.43mg/g (undewatered mash). It also appears that the process of producing the garri from the mash by heating, caused a further reduction of the cyanide content: thus the garri always contained less cyanide than the mash from which it was made. The lysine content of the mash was also highest when all three organisms were mixed; it also tended to increase with increasing length of fermentation of the mash. Whereas the single organism most effective in reducing the cyanide content of mash was Lactobacillus delbruckii, in the case of lysine production, it was the yeast. The organoleptic properties of the garri which were assessed were flavour, texture, colour and general acceptability. In general these properties were superior at the P,0.01 level in garri made from the undewatered mash in comparison with that from dewatered mash, especially when the mixture of organisms was used. The inoculation of the mixture of the three organisms produced a dramatic reduction in the time (24 h) taken for the highest ‘general acceptability’ score to be given by the tasters when compared with the singly inoculated organisms and the control, which attained this characteristic after about 96 h of incubation in mash. Published by Elsevier Science B.V.