In Vitro Antioxidant and Antihypertensive Activity of Edible Insects Flours (Mealworm and Grasshopper) Fermented with <i>Lactococcus lactis</i> Strains

The objective of the present study was to evaluate the potential antioxidant and angiotensin converting enzyme inhibition (ACEI) activity of edible insect flours fermented with <i>Lactococcus lactis</i> strains. For the fermentation, mealworm and grasshoppers flours were dissolved (0.5% <i>w</i>/<i>v</i>) in buffer solution (pH 7.0) and individually inoculated (3%) with <i>Lactococcus lactis</i> strains (NRRL B-50571, NRRL B-50572). The samples were incubated for 72 h at 30 °C, and the pH was recorded. The degree of hydrolysis (DH) and protein content were determined. The total polyphenol compounds, antioxidant activity (ABTS, DPPH, ORAC, and FRAP), and ACEI of the <3 kDa fractions were analyzed. The pH of the fermented samples decreased to 3.5–3.9 (<i>p</i> < 0.05). The fermented grasshopper flour showed an increased DH (0.42%) and overall higher total polyphenol content (8.23 mg Gallic Acid Equivalent/mL). In general, the highest antioxidant activity was for the grasshopper fractions fermented for 24 h by <i>Lactococcus lactis</i> NRRL B-50572, which also showed 23.47% ACEI inhibition with an IC₅₀ of 0.97 mg/mL. The peptide profile obtained increased after fermentation, being higher for the mealworm flour fermented sample. This study presents, for the first time, the use of specific strains of <i>Lactococus lactis</i> for fermenting edible insect-derived products in the production of bioactive compounds with potential antioxidant and antihypertensive activity.