Processo de biofermentação da polpa de juá e reaproveitamento do subproduto para alimentação.

Abstract

The present work was carried out with the objective of producing an alcoholic beverage of juá (Ziziphusjoazeiro) and elaborating a flour from the residue (peel and seed).After the collection, selection and sanitization of the fruits, it was realized the pulp extraction and physical-chemical characterization(water content, ash, proteins, lipids, carbohydrates, calories, total acidity, vitamin C, dietary fiber, reducing sugars, total sugars and non-reducing sugars). Before starting the fermentation process, the juá pulp was adjusted to the desired values of °Brix (11, 12, 13 and 14).Then, 3 L of the diluted pulpwas added in each bioreactor (4) with a capacity of 10 L, where the granulated yeast (Saccharomyces cerevisiae) was first placed.In each bioreactor, the cell concentration was 20 g / L. The same procedure was repeated for fresh yeast. A completely randomized design was used, in a 4 x 2 factorial scheme: four values of °Brix (11, 12, 13 and 14) and two types of yeasts (granulated and fresh).In this study, it was assessed the influence of the independent variables (values of ºBrix and yeast type) on the dependent ones (pH, residual Brix, cell count and alcohol content). After fermentation, the following steps were taken: racking to bottles, decantation and centrifugation of the supernatant. Then, the second part of the work was done: the distillation, carrying out the physical-chemical and chromatographic analyzes of the distillate, following the legislation for fruit spirits. The residue (peel and seed) was dried to produce the flour. This step aimed to study the drying behavior of the residue (peel and seed) of juá, at different temperatures and to define the temperature that reaches the breaking point (fragmentation) in less time, preserving the original characteristics of the raw material. For drying the product, the thin-layer method was used, at temperatures of 40, 50, 60 and 70 ° C.During this process, mass loss was monitored through periodic weighing, up to constant mass. The residues, both of the peel and of the seed, submitted to the four drying temperatures were ground (fragmented) until obtaining a uniform material.It wasconcluded that the physical-chemical characterization of the juá pulp presented the highest fractions for water content, carbohydrates and vitamin C, with values of 77.41%, 19.27% and 11.24%, respectively. Fermentation using both granulated and fresh yeast had an alcohol content of less than 4 ºGL (limit established by legislation to wait for fruit). Comparing the two types of yeasts, the granulated yeast had a better performance for alcohol content, conversion, biomass yield and productivity. In relation to ºBrix (input variable), there was no statistical difference between ºBrix 13 and 14, showing the best performance for both dependent variables and kinetic parameters. In the analysis of the distillate, the alcohol content, methanol and acetic acid are not in accordance with the legislation,however the other parameters (acetaldehydes, acetone, ethyl acetate and higher alcohols) are within the scope of the legislation for fruit spirits. All the tested models can be used to dry the peel and seed, and the Cavalcanti Mata model, in particular, was the one that best fit the data on the drying kinetics of the juá.The flours resulting from the experiment at a temperature of 70 ºC, for both peel and seeds, showed the best nutritional characteristics of proteins, ash and carbohydrates, in addition to having a water content within the value required by the legislation for flours, which is up to 15%.