Estudo da bioconversão do mandacaru (Cereus jamacaru P.DC.) para produção de bioprodutos.

Abstract

This research had as its main objective the use of whole Cereus jamacaru (plant and fruit) in the manufacturing of byproducts (nutritional enrichment, wine and vinegar) aiming to value this crop. The protein enrichment process of the plant was performed by semi-solid fermentation and the elaboration of wine and vinegar of the Cereus jamacaru fruit was made by submersed fermentation. Cereus jamacaru was used as a substrate in protein enrichment by two different microorganisms. Initially, protein enrichment of Cereus jamacaru with Aspergillus niger by semi-solid fermentation was studied, and the influence of the thickness of the layer (1.3 and 5 cm.) and the temperature (30, 34 and 38°C) were evaluated, where seven experiments were performed, three of them being on the central point, according to the 2 2 factorial planning. The crude protein content and the protein increase were assessed, and the results submitted to variance analysis. The greatest protein increase occurred after 72 hours of fermentation at a temperature of 30°C and with a layer of 1 cm thick. Later, Cereus jamacaru protein enrichment with Saccharomyces cerevisia yeast in rotational drums, with a concentration of inoculums at 5% and room temperature of 25°C, was studied, evaluating the protein and sugar content throughout 26 hours of fermentation. A maximum protein content of 23% was observed after 10 hours of fermentation. The protein enrichment obtained in this study presented contents of crude protein around 23%, which agrees with the NCR animal food norms (1989), and can be used as a protein supplement for animals during food scarcity in the semi-arid region. In the study of Cereus jamacaru adsorption isotherms, the Herderson model presented the best adjustments to the experimental data at temperatures of 25, 35 and 40°C, with the exception of the temperature at 30°C, which had a better adjustment to the GAB model. The second part of the study consisted in making a physical and physical-chemical characterization of the Cereus jamacaru fruit, and studying the kinetics of alcoholic and acetic fermentation in the manufacturing of Cereus jamacaru wine and vinegar using Saccharomyces cerevisiae yeast and acetic bacteria, respectively. The utilization of the fruit in the production of wine and vinegar is viable because of the high content of total soluble solids ( 1 1 °8rix) and total reducing sugars (9.82%) present in the fruit. Alcoholic fermentation was conducted in a bioreactor, in a loading system, at a temperature of 30°C ± 2°C. The cellular concentration, the substrate concentration, product concentration, total soluble solids, pH and total acidity were assessed throughout 48 hours of fermentation, The kinetic parameters obtained were: Y»s=0.075; YP ; S=0.469; Mmax=0.082 h"1; % Conversion and productivity of 91.82% e 3.04g/L.h, respectively. Acetic fermentation was conducted in a bioreactor, in loads, at a room temperature of 27°C ± 2°C. Concentrations of total, volatile, and fixed acidity, and that of ethanol were monitored every 24 hours. The greatest yield (67.4%) and productivity (0.29g/L.h) percentiles in the production of vinegar were obtained for the initial concentrations of ethanol and volatile acidity of 6°GL and 2% acetic acid, respectively. Cereus jamacaru wine presented an ethanol concentration (10.4°GL) within the specifications required by Brazilian legislation. The obtained Cereus jamacaru vinegar is within standards required by Brazilian legislation, with a volatile acidity over 4%. The production of wine and vinegar is a promising alternative in the utilization of Cereus jamacaru fruit.