Folhas de mandioca cozidas: avaliação do processamento e estudo de uma etapa de detoxificação

Abstract

This study evaluated the technological processes used to produce cooked cassava leaves (cooked manioc) considering the insertion of a detoxification process (rest test), aiming at reducing the total cyanide content. Ten samples of cooked cassava leaves commercialized in the city of Belém-PA were collected, five from fairs and five from supermarkets, where analyzes of cyanogenic (total cyanide, non-glycosidic cyanide and free cyanide), microbiological and physical contents were performed. -chemistry. The processes for producing cassava leaves cooked at fairs and agro-industries were verified. Good Manufacturing Practices (GMP) were verified by applying a checklist to two agro-industries. To study the detoxification process (rest test) the leaves were ground and remained at rest without and with added water at the times: 1.5; 3; 4.5; 6 and 24h, being performed analysis of cyanogenic compounds in all tests and pH only in fresh leaves and homes of 24h. Four processes of production of cooked cassava leaves were reproduced on a laboratory scale: two used in fairs and agroindustries (1 and 2) and two considering the rest tests that showed greater elimination of cyanogenic compounds (3 and 4). In the product of each assay, pH, cyanogenic and microbiological compounds analyzes were performed. Cyanogenic compound contents were determined by spectrophotometric reading at 605 nm. Microbiological analyzes were performed of: Salmonella spp, Bacillus cereus counts, coagulase positive staphylococci, coliforms at 45 ° C, mesophilic aerobes and mold and yeast. The physicochemical analyzes of moisture, ashes, proteins, lipids, carbohydrates, fibers, pH determination by direct reading in potentiometer and Total Titratable Acidity (TTA) were performed. The results of the cyanogenic compounds will vary from 1.25 to 8.22 mg HCN / kg, being 100% above the free cyanide legislation. All samples complied with legislation for Salmonella spp, coagulase positive staphylococci and Bacillus cereus. For coliforms at 45 ° C, 60% of the fair samples and 20% of the supermarket were in compliance with the legislation. The results of mesophilic and mold aerobic and yeast ranged from <2.40 to 5.38 and <2.88 to 7.30 log CFU / g, respectively. The fair samples were below the minimum recommended for humidity, lipids and pH and the supermarket samples, below the established for ashes, lipids and pH. Agroindustries were considered to be at high risk compared to GMP. The results of the detoxification study show significant difference between the pH of fresh leaves and the resting time of 24 h. The 6h rest tests with and without water showed greater elimination of cyanogenic compounds, so they were used in laboratory scale processing. Regarding the results of the processes on laboratory scale, There was no significant difference in the pH of fresh leaves compared to the products of the processes nor between the products 1, 3 and 4, in relation to the cyanogenic compounds and microbiological parameters. Changes in processing influence the contents of cyanogenic compounds, as well as the scarcity of GMP preceded by contamination. Resting tests contributed to the elimination of part of the cyanogenic compounds, however much of the conversion and elimination of HCN occurred in the leaf milling process, being this primordial step for detoxification and the previous grinding cooking proved unsatisfactory in relation to the parameters. cyanogenic and microbiological.