Estudo do aproveitamento do lactossoro de coagulação enzimática para fermentação e produção de aguardente.

Abstract

Cheese whey is a sub-product resulting from cheese production or from the extraction of casein and it contains approximately half of the solids present in milk. The usage of cheese whey is a way of minimizing the problems caused by its inadequate disposal, making this a highly interesting raw material in the manufacturing of innumerous products, and among them, a type of white-rum. The objective of this research was the production of this whiterum (a product which is much consumed in Brazil), using cheese whey as substrate, making it an alternative for small and medium-sized dairy industries. The ingredient used was the whey from a curdled type of fresh cheese produced in a dairy industry in the semiarid region of the Brazilian state of Paraíba. This whey was collected and packaged in a way that wouldn’t alter its composition. The whey was characterized, de-proteinized by the thermal acid method, in order to know its components, such as: minerals, proteins, lactose and total dry extract. Fermentation was performed in 6000 L Erlenmeyer containing 1000 L of de-proteinized whey, utilizing Saccharomyces cerevisiae yeast (commercial ferment), adding sucrose to the mean, knowing that S. cerevisiae doesn’t synthesize B-glycosidase, an enzyme capable of hydrolyzing lactose, which means that the whey presents itself essentially as a source of necessary minerals and amino acids necessary to the fermentative process. A study to verify the influences of the input variables (initial concentration of sucrose and initial concentration of innocuous) over the conversion response was performed, using an experimental planning method, observing that the best value found was of 76.14% of conversion in the experiment in which 130 g/L of sucrose and 1.8 g/L of innocuous were added. An increase in the scale in which the alcoholic fermentation was followed up during 44 hours was performed through the following determinations: pH, acidity (total, fixed, and volatile), total reducible sugars, soluble solid content, of ethanol and cellular concentration. From this fermentative process, 15 liters of ferment were obtained and it was centrifuged and distilled in a 20 L. copper distillery, being divided into fractions (head – 10%, heart – 80% and tail – 10%). The distilled product had a whitened aspect (clouded) and another distillation was necessary (bi-distillation). The product obtained was diluted and reintroduced to the distillery. The bi-distillation process didn’t have a different result from the original distillation, so a tridistillation was performed following the same process as the bi-distillation, and this produced limpid white- rum. In the physical-chemical analyses performed, both for the distilled white-rum and for the tri-distilled rum, a high proportion of ethyl carbamate and superior alcohols were observed, however the other secondary components (total esters, total aldehydes, furfural, methyl alcohol, acrolein, sec-butyl and n-butyl alcohols, cadmium, lead, and copper) are below the standards required by the Brazilian Legislation. The results obtained in the present paper show that the use of cheese whey is visibly promising for the production of white-rum. A more detailed study is necessary to minimize the undesirable components such as ethyl carbamate and the sum of the concentration of superior alcohols.