Citrus fruits are significant sources of bioactive compounds, such as ascorbic acid, polyphenols and carotenoids, due to their antioxidant properties important for human nutrition. In addition, since oranges possess high sugar content (8-15%), making vinegars from alcoholic orange substrates, with functional characteristics is a possible development of novel products. The aim of this research work was to analyze changes in ascorbic acid, total phenolics, total carotenoids and antioxidant activity during orange vinegar processing. In order to analyze the influence of acetification and aging in these characteristics, samples were taken in three stages: orange alcoholic substrate for acetification (SNA), young orange vinegar or recently obtained (Vn0) and orange vinegar after six month-aging in bottles (Vn6). Statistically significant differences (p < 0.05) were found among bioactive compounds concentrations; antioxidant activity decreased along the process, but total phenolics and carotenoids remained constant during aging period (Vn0-Vn6). The highest reduction was recorded during the acetification stage, possibly due to components oxidation caused by continuous air flow to the system. A higher contribution (p < 0.05) to antioxidant activity was associated to ascorbic acid and phenolic compounds concentration.

Ascorbic acid, carotenoids and polyphenols stand out among the orange juice natural antioxidants. The winemaking process affects their bioavailability and bioactivity. Antioxidant activities (AA) were estimated in different process conditions to asses those properties. The AA and their correlation with ascorbic acid, total phenolics and carotenoids content were calculated. The variables and levels analyzed were: pasteurized and natural must (PJ and NJ), pH 3.5 and 4.0 and fermentation temperatures at 10°C and 20°C. Statistically significant differences (α=0.05) were found among bioactive compounds concentrations. Antioxidant compounds concentration was higher in raw material than in orange wine. Juice pasteurization caused the major losses while subsequent vinification affects them to a lesser extent. Highest antioxidants retention was measured in wines from JN fermented at pH 3.5 and 10 °C (JN-3.5-10) followed by wines from JP and fermented at the same conditions (JP-3.5-10). AA determined by DPPH showed a positive and close correlation with FRAP, while ABTS showed a low correlation with former assays. Juice pasteurization process and fermentation temperature influenced bioactive compound reduction which correlates with the AA variation.

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fermentó con Saccharomyces cerevisiae hasta 14 % v/v de alcohol. La bioxidación se realizó con Acetobacter sp., en cultivo sumergido, en biorreactor de laboratorio. Para evitar el efecto inhibidor del etanol sobre las bacterias acéticas, el vino de naranja fue diluido a 6 % v/v de alcohol con solución de minerales. La influencia de las variables se evaluó con diseño factorial 2 k. Se estudió caudal de aire/velocidad de agitación, ensayando los niveles 0.3-0.6 vvm y 200-400 rpm y luego, caudal de aire/temperatura, siendo los niveles para cada variable 0.4-0.6 vvm y 25-30 ºC, respectivamente. Cada tratamiento se realizó por duplicado, usando como respuestas productividad y rendimiento. El análisis del diseño (α<0.05) se efectuó mediante programa Statgraphics Centurion XV Corporate. En los tratamientos con 200 rpm y distintos caudales de aire, no hubo diferencias significativas respecto a la productividad. A mayor velocidad de agitación y caudal de aire, la productividad fue mayor. Los mayores rendimientos se obtuvieron con menores caudales de aire y mayores velocidades de agitación. Con respecto a la temperatura, los valores ensayados no presentaron diferencias significativas en las respuestas estudiadas. El mejor rendimiento se obtuvo con 400 rpm y 0.3 vvm a 25 ºC. Se concluye que la velocidad de agitación juega un rol muy importante para lograr una mejor productividad mientras que elevados flujos de aire disminuyen el rendimiento.

Sixteen acetic acid bacteria (AAB) were isolated from blueberries and citric fruits of the Salto Grande region (Concordia, Entre Ríos, Argentina) using enrichment techniques and plate isolation. Enrichment broths containing ethanol and acetic acid enabled maximum AAB recovery, since these components promote their growth. Biochemical tests allowed classification of the bacteria at genus level. PCR-RFLP of the 16S rRNA and PCR-RFLP of the 16S-23S rRNA intergenic spacer allowed further classification at the species level; this required treatment of the amplified products of 16S and 16S-23S ITS ribosomal genes with the following restriction enzymes: AluI, RsaI, HaeIII, MspI, TaqI, CfoI, and Tru9I. C7, C8, A80, A160, and A180 isolates were identified as Gluconobacter frateurii; C1, C2, C3, C4, C5, C6, A70, and A210 isolates as Acetobacter pasteurianus; A50 and A140 isolates as Acetobacter tropicalis; and C9 isolate as Acetobacter syzygii. The bacteria identified by 16S rRNA PCR-RFLP were validated by 16S-23S PCR-RFLP; however, the C1 isolate showed different restriction patterns during identification and validation. Partial sequencing of the 16S gene resolved the discrepancy.

Blueberries are widely recognized for their beneficial health effects due to their bioactive compounds content. In addition, balsamic vinegars trade developed quickly because of their wide acceptance in gourmet food. A novel product made with second quality berries, being suitable for human consumption, i.e., blueberry balsamic vinegar, was evaluated. This work aimed to assess changes in Total Anthocyanins (TA), Total Phenolics (TP), and antioxidant activity during production process of blueberry balsamic vinegar, at the following stages: raw material, blueberries juice after enzyme treatment, blueberries alcoholic substrate, blueberries vinegar, concentrated blueberry juice and blueberries balsamic vinegar. Additionally, three alternative evaporation systems, rotary vacuum evaporator, microwave and vacuum microwave, were evaluated in order to determine the concentration method that best retains TA and TP in blueberry juice for its further use in this process. The highest TA and TP retention was achieved by blueberry juice concentration with a rotary vacuum evaporator. On the other hand, both alcoholic fermentation and acetification negatively affected those compounds and antioxidant activity during vinegar production. However, mixing with concentrated juice to obtain blueberry balsamic vinegar allowed balancing nutrient concentration reductions due to processing. The present study showed that production of blueberry balsamic vinegar gives rise to an interesting possibility to reduce losses due to fruit waste while getting added value products with healthy qualities.

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Recently, there has been growing interest in the characterization of native yeasts for their use in production of wines with regional characteristics. This study aimed to investigate Saccharomyces and non-Saccharomyces yeasts present in the spontaneous fermentation of Tannat and Marselan grape musts collected from Concordia (Entre Ríos, Argentina) over 2019, 2020, and 2021 vintages. The evolution of these fermentative processes was carried out by measuring total soluble solids, total acidity, volatile acidity, pH, ethanol concentration, and total carbon content. Isolated Saccharomyces and non-Saccharomyces yeasts were identified based on colony morphology in WL medium, 5.8S-ITS-RFLP analysis, and 26S rDNA D1/D2 gene sequencing. Two hundred and ten yeast colonies were isolated and identified as Pichia kudriavzevii, Saccharomyces cerevisiae, Hanseniaspora uvarum, Metschnikowia pulcherrima, Candida albicans, Candida parasilopsis, Pichia occidentalis, Pichia bruneiensis, Hanseniaspora opuntiae, Issatchenkia terricola, and Hanseniaspora vineae. P. kudriavzevii isolated from all vintages was associated with the spontaneous fermentation of grape musts from the Concordia region.