ATENUATION OF L. ACIDOPHILUS USING OHMIC HEATING IMPROVES GENERATION OF BIOACTIVE COMPOUNDS IN MINAS FRESCAL CHEESE

Attenuation is an important strategy for controlling the metabolic activity of probiotic cultures through different treatments that delay or avoid undesirable effects on the food resulting from the probiotic's fermentative metabolism. To date, conventional heat treatment has been the most widely used attenuation method, while studies involving the use of emerging technologies to attenuate probiotics are scarce. In this context, this study investigated ohmic heating (OH; 4, 8 and 12 V/cm, 52oC / 6 min at 60 Hz) to attenuate Lactobacillus acidophilus LA 05 (8 log CFU/g) with subsequent addition to Minas Frescal cheese processing. Five cheeses were produced: without probiotic (CONT), with probiotic (PROB, 8 log CFU/g), and three with attenuated L. acidophilus (OH4, OH8, OH12). Proteolysis (OPA method) and biological activity were evaluated by in vitro antioxidant (2,2-Diphenyl-1-picrylhydrazyl [DPPH]), antidiabetic (α-amylase and α-glucosidase inhibition), and antihypertensive (Angiotensin-converting enzyme [ACE] inhibition) activities. All analyses were performed on storage days 1, 7, and 14. Attenuation was able to increase the bioactive compounds level (DPPH values, 45.6-35.1% against 13.2-26.2%), ACE values (29.7-26.7 against 5.7-19.9%), α-amylase values (23.9-19.5 against 12.76.78%), α-glucosidase values (27.8-22.4 against 18.6-8.90%) and proteolysis indexes (0.43-0.31 against 0.27-0.12), with this change observed along the storage time (14 days) and noticed mainly at low OH values, namely 4 V/cm. The results suggest that attenuation using ohmic heating may be an interesting option to increase the biological activity and consequently, the functional level of probiotic Minas Frescal cheese. Therefore, ohmic heating proved to be an effective technology for attenuating probiotic microorganisms, providing the development of a high-quality functional product.