Total and Free Hydrogen Cyanide Content and Profile of Bioactive Amines in Commercial Tucupi, a Traditionally Derived Cassava Product Widely Consumed in Northern Brazil.

Tucupi is a broth derived from cassava roots which is produced after the spontaneous fermentation of manipueira (the liquid portion obtained by pressing cassava roots), followed by cooking. This product is widely consumed along with traditional dishes in the Brazilian Amazonia and is already used in different places worldwide. In this study, tucupi obtained from the markets of Belém (Pará, Brazil) and produced using agroindustrial (11 samples) and non-agroindustrial (11 samples) units were investigated to determine their physicochemical characteristics, total and free HCN contents, and free bioactive amine profiles. Most of the samples showed significant variations (p ≤ 0.05) in pH (2.82-4.67), total acidity (0.14-1.36 g lactic acid/100 mL), reducing sugars (up to 2.33 g/100 mL), and total sugars (up to 4.35 g/100 mL). Regarding the amines, four biogenic amines (0.5-4.2 mg/L tyramine, 1.0-23.1 mg/L putrescine, 0.5-66.8 mg/L histamine, and 0.6-2.9 mg/L tryptamine) and one polyamine (0.4-1.7 mg/L spermidine) were identified in the tucupi samples. Even in the tucupi produced using the agroindustrial units, which had quality seals provided by the local regulatory agency, high levels of biogenic amines (4.4-78.2 mg/L) were observed, as well as high dosages of total (8.87-114.66 mg/L) and free (0.80-38.38 mg/L) HCN. These facts highlight the need for better knowledge regarding the product manufacturing process to establish standardization and high-quality conditions for tucupi processing since high contents of biogenic amines and HCN are commonly associated with adverse health effects.

Lactic Acid Bacteria and Bioactive Amines Identified during Manipueira Fermentation for Tucupi Production.

There is scarce information regarding lactic acid bacteria (LAB) and the production of biogenic amines during manipueira fermentation for tucupi. Thus, the objective of this study was to isolate and identify LAB, and to determine their impact on bioactive amine formation. Spontaneous fermentation of manipueira was carried out at laboratory scale and selected LAB colonies were isolated and identified by sequencing techniques and comparison with sequences from a virtual database. Only two LAB species of the genus Lactobacillus were identified during fermentation: Lactobacillus fermentum and Lactobacillus plantarum. L. fermentum was the predominant, whereas L. plantarum was only detected in manipueira prior to fermentation. Spermidine and putrescine were detected throughout fermentation, whereas histamine was produced at the final stage. There was positive correlation between LAB counts and putrescine and histamine levels, suggesting that the identified LAB are responsible for the synthesis of these amines during manipueira fermentation. Genetic assays are needed to verify whether the LAB identified have the genes responsible for decarboxylation of amino acids.