Gourmet vinegars are versatile culinary ingredients that have aroused the interest of consumers not only for their unusual taste, but also for their health benefits. In this work, blueberry and honey wine was first obtained using a bench-scale bioreactor. This wine had high concentrations of phenolic compounds (706.18 mg GAE/mL) and appreciable free radical scavenging ability against DPPH (161.42 µmol trolox equivalent/100 mL) and ABTS•+ (356.41 µmol trolox equivalent/100 mL), as well as ferric-ion reducing antioxidant capacity (1419.86 µmol FeSO4/100 mL). In sequence, vinegar was produced from the wine in wooden barrels using successive acetification cycles. The average acetic acid concentration found in the vinegars was 4.4 g/100 mL, and the average acetic acid yield and volumetric productivity were 52.69% and 0.38 g/(L.h), respectively. Appreciable polyphenolic compounds (681.87 to 847.98 µg GAE/mL) and anthocyanin (12.8 to 15.39 mg/L) contents were found and high antioxidant activity. In addition, the vinegars demonstrated antimicrobial ability against Bacillus subtilis and Salmonella enterica Typhimurium.

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Syzygium malaccense belongs to the family Myrtaceae and it is popularly recognised as ‘jambo’ in Brazil. It is poorly studied regarding the bioactive compounds of fruits and leaves. This study aimed at optimizing the extraction and characterization of bioactives compounds from S. malaccense leaves. Extraction was optimized using a 23 full factorial design to evaluate the effect of ethanol concentration, time and temperature on polyphenols and antioxidants contents. Analyses of phenolic compounds content (Folin-Ciocalteau and HPLC-DAD), in vitro antioxidant capacities (DPPH, ABTS and FRAP), antimicrobial activity against bacteria and yeasts of ethanolic extract was carried out in optimal conditions of extraction. The optimized extraction condition was 45 min., 80°C and 40:60 (v v-1) ethanol:water. The extract showed high total phenolic content (0.074 mg GAE kg-1), DPPH (0.666 μmol TE kg-1) and ABTS (0.853 μmol TE kg-1) free radical scavenging ability and appreciable ferric reducing power (1.267 μmol Fe2+ kg-1). HPLC methodology allowed the identification of four bioactive compounds: gallic acid (0.00036 mg kg-1), catechin (0.00021 mg kg-1), rutin (0.00027 mg kg-1) and quercetin (0.00003 mg kg-1). The extract showed inhibitory activity against S. aureus (1 µg L-1); S. bongori (8 µg L-1), C. albicans and C. tropicalis (2 µg L-1). It also showed microbicidal potential against S. aureus; C. albicans and C. tropicalis.

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