Produção de cerveja artesanal com adição de goiaba vermelha e flocos de aveia.

Abstract

Craft beers have special characteristics, and for this reason have been gaining more and more space in the national market and conquering the palate of many consumers. Fruits are rich in essential nutrients and micronutrients such as minerals, fiber and vitamins, and secondary compounds such as phenolics, called polyphenols. The use of fruit incorporates several sensorial characteristics in the beer, changing its flavor, aroma and color. Thus, the objective of the present work was to produce and standardize a craft beer recipe with the addition of red guava pulp and oat flakes and to perform the kinetic monitoring of the fermentation process. Unpasteurized craft beerhad the production process carried out at the Center for Sustainable Development of the Semi-Arid Region (CDSA), at the Federal University of Campina Grande (UFCG) in Sumé-PB. Mineral water, Pilsen malt, HallertauHallertau Blanc hops, Yeast Fermentis US-05, Guava and oat flakes were used as raw materials. During production, the steps of malt grinding, mashing, filtration, boiling, cooling, fermentation, maturation, priming, bottling and carbonationwere carried out. During the fermentation stage, aliquots were collected to carry out triplicate analyzes of pH, total soluble solids content (ºBrix) and cell concentration (g.L-1), in order to determine cell growth, substrate consumption and ethanol production . Fermentation took a total time of 100 hours and at the end the product had an alcohol content of 5.29% (ABV%) and a pH of 4.24. In craft beers with the addition of fruit pulp, the alcohol content as well as the pH can vary depending on the fermentable sugars and acidity of the fruit. After 48 hours, the concentrations of product and substrate maintained their values with small changes, this time was used as a basis for calculating the substrate-to-product conversion parameter, obtaining a value of 86%. As for the substrate conversion parameter in cells, times from 4 to 24 hours were used, in which the achieved conversion was 220%. The cell growth rate at this stage was 0.363 g.L-1.h, and the cell productivity was 0.329 g.L-1.h. Regarding the specific rate of cell growth (μx) in the interval from 4 to 24 hours of fermentation, a value of 0.074h-1 was obtained and, therefore, a generation time (t_g) of 9.635h. The value referring to the substrate consumption obtained was 0.139 g.L-1.h. Thus, it is possible to consider that the elaboration of artisanal beer with the addition of red guava pulp and oat flakes proved to be very promising. The beer had a light color with low levels of aroma and fruit flavor, this was due to the guava pulp having been added at the beginning of the boil, following the assumption that heat can vaporize or degrade important substances responsible for the characteristic aroma and flavors of the beer. fruit, however the addition of fruit at this stage was relevant, regarding the formation of ethanol and pH value. The yeast Fermentis US-05 showed compatibility with the environment and operating conditions, with higher productivity and formation speeds being observed than those found by other researchers, who also studied the production of artisanal beer with the addition of fruit.