Estudo Econômico e Cinético de Duas Lactases Comerciais

Abstract

Lactose is the main sugar in milk, being divided into glucose and galactose by the action of the enzyme lactase. Some people have deficiency of this enzyme in the body, therefore, causing lactose intolerance. In this context, there is a need to produce zero lactose foods, due to the need to optimize manufacturing processes, as well as the production of quality and safe food to the consumer. In this work, the hydrolysis of lactose by the commercial enzymes β-galactosidase of yeast origin Kluyveromyces lactis, and the filamentous fungus Aspergillus oryzae was evaluated. In this scenario, a Rotational Composite Central Design (DCCR) was used to study the hydrolysis of lactose, analyzed in 5 levels of variation to evaluate the effect of different factors, and the concentration and time were the same for the two lactases, and the temperature the central point where the highest activity of each enzyme occurs. For K. lactis, temperatures of 9.8; 20; 35; 50; and 60.2°C and for A. oryzae 29.8; 40; 55; 70; and 80.2°C. After the tests were carried out according to the design, the quantification of the lactose was performed by High Efficiency Liquid Chromatography, with refractive index detector (HPLC-RID). The results were evaluated by (ANOVA) and response surfaces, with significance limit of 5% (p <0.05). The regression models of lactose hydrolysis adequately explained at the 95% level, obtaining a variation of the data of R2 = 0.8159, for K. lactis and R2 = 0.8895 for A. oryzae, taking into account that the linear (temperature and concentration) and quadratic (temperature) terms were significant in both enzymes. The maximum hydrolysis reached by the experiments was 98.59% for K. lactis at 35 ° C and 94.14% for A. oryzae at 55 ° C for both the concentration 0.70% (v/v) and the time 195 minutes, were the same. With these variables, response surface graphs were generated to analyze the best optimized conditions according to the experimental model, with 145 minutes for both, a concentration of 0.49% (v/v) at 30,80°C for K. lactis (100%) and 0.51% (v/v) concentration at 41.40°C for A. oryzae (98.24%). Despite the high hydrolysis values obtained, only K. lactis can meet RDC No. 135/2017 for zero lactose products. Therefore, the final product had 0.07 g / 100 ml, a result below that required. Therefore, taking into account that the enzymes used were purchased locally, the purpose is to provide the consumer with the cost-benefit information of the product used to control lactose intolerance, which in this case K. lactis was economically more viable.