Redução de bactérias ácido-láticas (BAL) no permeado do soro do leite com a utilização da colônia simbiótica de bactérias e leveduras – (SCOBY)

Abstract

Daily, tons of liters of whey permeate are produced, the improper disposal of which significantly impacts the environment and public health due to the high load of lactose, salts, water, and other compounds. In light of this scenario, the use of Symbiotic Culture of Bacteria and Yeasts, known as SCOBY, can be a potential alternative for study, presenting SCOBYs as a natural, organic, and sustainable solution for repurposing whey permeate from a dairy industry. The industry seeks alternatives for the reuse of this waste, aiming for an appropriate destination for the byproduct, whey. SCOBY produces the beverage known as Kombucha. In this study, three (3) types of Kombucha SCOBYs were used: one (C) commercial, and two artisanal (A and B) from producers in the southwest region of Paraná. This work analyzed the physicochemical and microbiological characteristics of SCOBY in whey permeate, evaluating the reduction in the proliferation of lactic acid bacteria in the medium after 21 days. The experiment was distributed into treatments 1 to 10, using permeate from nanofiltration before being directed to the treatment lagoon. Ten (10) formulations were prepared for the analyses, varying from 20, 30, and 40 grams of SCOBY per liter of permeate, in addition to a formula without SCOBY inoculation, using only the permeate at a temperature of 26.8°C in an incubator. Physicochemical and microbiological analyses were conducted on the pure whey permeate and after 21 days treated with commercial and artisanal Kombucha SCOBYs. The results indicated a significant reduction in the microbial load in all the formulations evaluated, demonstrating a notable change in pH in the permeate, which ranged from 6.88 at the beginning of the experiment to a pH of 3.15 at the end for the "Commercial" SCOBY, pH 5.61 for "Artisanal A," and an increase in pH to 7.74 for "Artisanal B." This behavior suggests that the SCOBY promotes the acidity of the medium and contributes to the reduction of lactose present in the whey permeate. The acidity, measured in Dornic degrees, was inversely proportional to the pH, with higher values for the artisanal SCOBYs. In the microbiological analysis of the pure permeate, the presence of 1.4 x 10-4 CFU/mL of lactic acid bacteria (LAB) was found. All the formulations analyzed showed excellent performance in reducing LAB, with these being absent in the final product. Therefore, it can be stated that the SCOBY acidifies the medium and reduces the lactose in the whey permeate. This study highlights the potential of SCOBY as a viable alternative for the treatment and sustainable reuse of whey permeate, contributing to mitigating environmental impacts and promoting the valorization of industrial byproducts.