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In this study, the nonanthocyanin (poly)phenolic profile of an alcoholic-fermented strawberry beverage was characterized. High-performance liquid chromatography coupled with a triple-quadropole mass spectrometer and ultra-high-performance liquid chromatography coupled with a linear trap quadropole and an Orbitrap mass analyzer was used to identify nonanthocyanin phenolic compounds. Sixty-six compounds were identified, and 13 of these were identified for the first time in strawberry or its derived alcoholic fermented beverage: protocatechuic acid-4-O-β-hexoside, brevifolin carboxylic acid, ferulic acid glucuronide, dimer caffeic acid-O-hexoside, luteolin-3'-O-xyloside, isorhamnetin 3-O-glucoside, taxifolin-O-glucoside, (+)-aromadendrin rhamnoside, eriodictyol-7-O-glucoside, (+)-taxifolin, (+)-aromadendrin, eriodictyol, and homovanillic acid. The alcoholic fermentation process produced significant increases in certain compounds, such as homovanillic acid and p-hydroxybenzoic acid, while a significant decrease in galloyl bis-HHDP-glucose was observed. Linear discriminant analysis correctly classified samples initial, final, and pasteurized, which led to the conclusion that alcoholic fermentation induces significant changes in composition, mainly in relation to the 19 compounds represented in the tables of this work.

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The many uses of gluconic acid and some of its salts are arousing increasing interest in these compounds and in their production levels. Although gluconic acid and gluconates can be obtained chemically, they are currently almost exclusively biotechnologically produced, mostly by fungus based methods. There is, however, an ongoing search for alternative microorganisms to avoid the problems of using fungi for this purpose and to improve the productivity of the process. Especially promising in this respect are acetic acid bacteria, particularly Gluconobacter strains. This paper discusses the main variables and operating conditions to be considered in optimizing gluconic acid production by Gluconobacter.

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The nitrogen source for acetic acid bacteria is important during the vinegar making process. There can be great variation in the final result according to the specific source, the total nitrogen availability and the operational conditions. These bacteria use L-proline, L-leucine and ammonium ion as their main source of nitrogen from white wine. The effect of loading and air-flow rates on the changes in amino acids, urea and ammonium ion contents have been studied for a semi-batch submerged wine vinegar controlled production. Experiments were carried out in a Frings 8L fermenter working in a semi-batch mode. Amino acid contents were determined from their dansyl derivatives on an HPLC furnished with a C18 reversed-phase column. Urea and ammonium ion contents were quantified with an enzymatic kit. Specific nitrogen consumption is given for 25 amino acids and ammonium ion. In addition, profiles for main system variables as well as the three main nitrogen sources (ammonium ion, L-leucine and L-proline) are given. Type of loading and air-flow rates seemed to have a strong impact on the consumption of the nitrogen compounds tested. An increased loading rate and decreased air-flow rate resulted in greater overall consumption of available nitrogen due to different causes. Nitrogen requirement of the bacteria is proportional to the time spent in the acetification process. An acetification procedure involving relatively sudden changes in the fermentation medium may be desirable in order to reduce the formation of urea.

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