Antioxidant and anti-inflammatory properties of yeasts fermented passion fruit and soursop pulps: A focus on bioactive volatile compounds profile

This work aimed to ferment pasteurized soursop (SF) and passion fruit (PF) pulps inoculated with different yeast strains (Saccharomyces cerevisiae subsp. boulardii CNCM I-745 and Saccharomyces bayanus Safcider AB-1) incubated at 37 °C for 30 h. Throughout fermentation, the concentration of viable cells, soluble solids, and pH were evaluated. In vitro antioxidant and anti-inflammatory activities were determined in the fermented pulps. Additionally, volatile compounds and fatty acids were analyzed by gas chromatography-mass spectrometry. Fermented pulps showed viable cell counts higher than 109 CFU/mL from 12 to 30 h of fermentation, with a significant decrease (p < 0.05) in soluble solids, and constant pH values (3.30 and 4.09 in PF and SF, respectively). PF and SF pulps fermented by S. boulardii, and PF pulp fermented by S. bayanus showed antioxidant activities of 5.142, 5.011, 5.142 and 1.615 mg eq. Trolox/mL by ABTS, respectively. PF pulp fermented by S. bayanus as well as PF and SF pulps fermented by S. boulardii showed antioxidant activities of 0.628, 0.811 and 1.170 mg eq. Trolox/mL by FRAP, respectively. The PF and SF pulps fermented by S. bayanus showed inhibition of protein denaturalization activity (ca. 70% and 85%, respectively), while in SF pulp fermented by S. boulardii the inhibition of heat-induced hemolysis was ca. 90%. Alcohols, esterified carboxylic acids, unsaturated fatty acids (linolenic > linoleic > oleic), and polyphenols were identified in fermented pulps. These findings demonstrate that through controlled yeast fermentation, the potential health-promoting properties of fruit pulps can be improved, generating new fermented functional foods.