Aproveitamento de produtos derivados de levedura (Saccharomyces spp.) para o enriquecimento nutricional de alimentos à base de mandioca (Manihot esculenta CRANTZ)

Abstract

The yeast (Saccharomyces spp.) are used in various processes fermentativos. O Brazil currently produces a large amount of yeast biomass as a byproduct of the brewing industry. In the process of beer production, after maturation, these microorganisms are removed from the fermented mash of surplus generating cells, which are discarded in the environment or primarily used in animal feed. Yeasts have a nutritional potential, especially in protein, B vitamins and minerals, which thus could be utilized as a nutritional ingredient for human consumption, such as regional foods derived from cassava (Manihot esculenta CRANTZ). The cassava flour and tapioca are widely consumed by the population in the Northeast, but have low protein content, being considered only as an energy source. The objective of this study was to evaluate the nutritional status and potential use of derivatives of secondary yeast in the brewing industry as an ingredient in nutritious food, preparing cassava flour and tapioca added dried yeast and evaluate the nutritional enrichment and sensory acceptance of regional products. The samples were provided by a brewery in Feira de Santana, BA, at two times (batch 1 and 2) and subjected to an alkaline treatment (0.3% NaOH), centrifugation and washing with disposal of the supernatant to obtain a reduction of bitterness and clean biomass (BMT). A portion of the sample was not subjected to this treatment for nutritional assessment of potential losses. The biomass was lyophilized to obtain BMNL (before treatment) and BMTL (after treatment). The chemical composition was performed in triplicate in wet biomass in freeze-dried products and regional standard (freeze-dried without addition of yeast) and enriched by BMTL concentrations of 5 and 10%. Measurements of minerals and B vitamins were performed in triplicate, in a lot of BMNL and BMTL. The minerals were determined by atomic absorption spectrometry and the B vitamins by high performance liquid chromatography. Microbiological tests were performed in the flour and tapioca default, the freeze-dried biomass and in compliance with current legislation, to ensure their safety for consumption. The sensory test was carried out by untrained panelists using a hedonic scale from 1 to 9 points, and evaluated the attributes: color, taste, bitter taste, texture and overall quality and standard of enriched products. The purchase intention was assessed using a scale of 1 to 5 points. Samples of food were served as manioc and tapioca artificially colored and flavored. It can be inferred that biomass, and especially, the pellet is characterized by an important source of protein, respectively 11.4 and 35.2 g% g% with the possibility of an ingredient to add nutritional value of food protein. The alkaline treatment had no effect on protein losses. The BMTL showed excellent levels of calcium (699mg%), iron (10.59 mg%), selenium (0.5 mg%) and zinc (9.68 mg%), and composition of vitamins B1 (0.45 mg%), B2 (2.34 mg%), B3 (0.70 mg%), B6 (9.99 mg%) and B9 (0.25 mg%). Generally, the treatment cleaning and reduction of bitterness influenced in significant losses of minerals and vitamins. Fortified foods showed a significant increase in protein content compared to the same standard products, and found to be safe for sensory testing, according to the microbiological analysis. The average acceptance test were inversely proportional to the addition of dried yeast. The product enriched with better acceptance and better average purchase intent was the crumbs with 5% lyophilized. The dried yeast can be considered as a nutritional supplement with the potential to be used as a form of food enrichment. Techniques to minimize the bitter taste this derivative and the addition of plant extracts and other xviii flavorings could improve the acceptance of the preparations, and enable its use for improving the nutritional value, especially of proteins in foods. Keywords: brewer's yeast, a byproduct, dried yeast, enriched cassava flour, cassava bread enriched