Resumo O presente trabalho teve como objetivo estudar a melhor composição do meio de fermentação para máxima produção de lactase por Saccharomyces fragilis IZ 275 usando diferentes fontes de carbono incluindo o soro de queijo em pó reconstituído. Primeiramente, um delineamento fatorial 24 foi aplicado para verificar dentre as variáveis estudadas as que apresentavam efeito significativo. Logo após, foi aplicado um delineamento de máxima inclinação ascendente e máxima inclinação descendente para obter a máxima atividade. Para otimizar o meio de fermentação, foi então, realizado um delineamento Composto Central Rotacional (DCCR) 24. Foi observado que o soro de queijo, um subproduto da indústria de lacticínios, e altamente poluidor para o meio ambiente, pode ser empregado como excelente meio de fermentação por leveduras, dentro do conceito de bioeconomia com valor agregado. O emprego da metodologia é uma ferramenta eficiente para otimizar o processo de produção da β-galactosidase. No meio de fermentação otimizado, a máxima produção de β-galactosidase (54,68 U/mL) por S. fragilis IZ 275 é obtida com 14 g/L sacarose, 17,7 g/L soro de queijo em pó reconstituído, 5,14 g/L extrato de levedura e 8,85 g/L peptona.

Abstract This study sought to create a better fermentation medium to maximize lactase production by Saccharomyces fragilis IZ 275 using different carbon sources, including reconstituted powdered cheese whey. A factorial design 24 was applied to evaluate the significant effects of variables which compose the fermentation medium. Then, a steepest descent-ascent design was applied to obtain the maximum activity. A Rotational Central Composite Design (RCCD) 24 was made to optimize the fermentation medium. We verified that the cheese whey, a by-product of the dairy industry, can be employed as an excellent fermentation medium by yeast, within the bioeconomy concept and used by the dairy industry as product with additional value. The employed methodology is an efficient tool in the optimization process for β-galactosidase production. In the optimized fermentation medium, the maximum production of β-galactosidase (54.68 U/mL) by S. fragilis IZ 275 is obtained with 14 g/L sucrose, 17.7 g/L reconstituted powdered cheese whey, 5.14 g/L yeast extract and 8.85 g/L peptone.

Abstract This work aimed to evaluate the performance of different drying methods in the development of phenolic compounds, methylxanthines, and antioxidant activity in cocoa bean and to evaluate the presence of ochratoxin A (OTA). Antioxidant activity was determined using DPPH, FRAP, ORAC and β-carotene-linoleic acid assays. Phenolic compounds and methylxanthines were determined using high-performance liquid chromatography with an ultraviolet detector (HPLC-UV). OTA was determined by ultra-performance liquid chromatography with fluorescence detection (UPLC-FLR). It was found that during cocoa drying, there was a reduction in antioxidant activity with reduced phenolic compound content (0.04 mg.g-1 of catechin before drying to 0.02 mg.g-1 after drying) and reduced methylxanthines (19.44 mg.g -1 of theobromine before drying to 11.71 mg.g-1 after drying). Only one sample showed contamination by OTA (7.1 μg.kg-1). The traditional drying method showed the highest conservation of antioxidant activity and methylxanthine and phenolic compound content.