Linamarase Research Articles

Use of Bacteria that Produce Linamarase in Cassava Processing for Gari

Assessment of the effectiveness of microorganisms involved in gari fermentation in the degradation of cyanogenic glucosides was studied. Alcaligenes faecalis, Lactobacillus plantarum, Bacillus subtilis and Leuconostoc cremoris were isolated from cassava waste water while standard analytical methods were used to monitor the fermentation for total cyanogens. The linamarase activity observed for the isolates ranged from 0.0416 imol/ml/nmol (Lactobacillus plantarum) to 0.2618 imol/ml/nmol (Leuconostoc cremoris). Bacillus subtilis did not express any activity for the enzyme. Values obtained for total cyanogenic glucosides differed significantly at 24 h and 48 h (p 0.05). At 24 h, the cyanohydrins did not differ among the fermenting organisms. However, the mixed culture had the least amounts from 48 h to 96 h. Free cyanide produced by each organism did not differ at 24 h and 48 h but visible differences were observed at 72 h and 96 h. B. subtilis had the highest amount at 96 h (38 mg HCN/ kg) while the mixed culture had the least amount (26 mg HCN/kg). There was no significant difference in the rate of degradation of the linamarin by the microorganisms. pH decreased with increase in time of fermentation with the mash fermented by the mixed culture having the lowest pH of 4.19 at the end of fermentation. Titrable acidity increased with increase in fermentation time with the highest value of 1.05% at 96 h of fermentation produced by the mixed culture of microorganisms. These results show that although these isolates produced linamarase, their activities did not significantly affect the breakdown of the cyanogens.

Effect of processing conditions on cyanide content and colour of cassava flours from West Africa

The evolution of cyanide content and colour were monitored during the processing of lafu, traditional flour and improved flour from five cassava cultivars from Benin. In addition, the total phenol, polyphenoloxidase (PPO), peroxydase (POD) and linamarase activities were assessed. The processing of cassava in lafu and improved flour proved superior for producing safe and white non-fermented and fermented cassava flours with total cyanide mean values of 16.6 and 11.4 mg HCN/kg, db and ΔE values of 9.2 and 12.1, respectively. Detoxification appeared to be only linked to processing, in particular to the size reduction level of cassava roots, regardless of the initial cyanide level and the linamarase activity of the fresh roots. Cassava flour yellowness was closely linked to the phenol content (r = 0.95) that decreased after steeping and pressing. The PPO and POD activities did not appear to be linked to flour discoloration.

Influence of media composition on linamarase production by some fungi.

Description de la production de linamarase (linamarin β-glucoside glycohydrolase) par cinq fungi: Aspergillus sydowi, Aspergillus oryzae, Aspergillus ochraceus, Penicillium stickii et Fusarium equiseti

Isolation of linamarin-lotaustralin from Trifolium repens

Linamarin and lotaustralin were isolated as a mixture from Trifolium repens L. and used as substrate for the assay of linamarase