In this study the effect of the ozonation procedure on the microbiological and antioxidant status of raspberries stored at room temperature was investigated. During the study, it was found that ozonation with a dose of 8–10 ppm for 30 min, every 12 hours, for 3 days effectively reduced the growth of aerobic mesophilic bacteria and fungi. On the last day of storage, infestation with Botrytis cinerea for control fruit amounted 100%, while for ozonated fruits it was only 12%. In addition, the ozonation process has preserved the high antioxidant potential of the fruits and reduced the loss of polyphenol compounds, including anthocyanin. The applied procedure was proven to be effective, showing the potential of ozone as a factor extending the high commercial and consumer value of fruit stored at room temperature.

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Multistage crystallization has been used for resolution of the racemic mixture of citalopram to obtain pure S-citalopram. The racemate was converted to a diasteromeric salt pair using (+)-O,O′-di-p-toluoyl-d-tartaric acid, (+)DTT, as a resolving agent. The obtained salts involved solid solutions almost within the entire range of the crystalline phase composition, which excluded the possibility of a single-stage resolution. Therefore, a multistep crystallization technique was employed that allowed enrichment of the racemate with the desired diastereomer in the liquid phase. Moreover, a procedure for restoring the 1:1 composition of the depleted solid phase has been developed. The procedure was based on formation of a diasteromeric salt pair with the opposite enantiomer of the resolving agent, i.e., (−)DTT. Copyright © 2012 American Chemical Societ

ABSTRACT:A procedure for the isolation of the most biologically active component of a stereoisomeric mixture of nafronyl -2-(diethylamino)ethyl 3-(naphthalen-1-yl)-2-((tetrahydrofuran-2-yl)methyl)propanoate, has been proposed. The molecule of nafronyl is a representative of compounds possessing two stereogenic centers, which may be produced in the form of a quaternary mixture that contains two pairs of racemates being diastereoisomers of one another. The components of such stereoisomeric mixtures usually differ in pharmacological activity, therefore, there is an interest in developing efficient methods for their resolution. The method suggested in this study comprised two sequential separation processes, including multistage cross-current crystallization and chiral chromatography.Crystallization was employed to enrich the raw material mixture with the target racemate, which contained the stereoisomer exhibiting the highest biological activity. To intensify the process, the mother liquors depleted with the target racemate were subjected to fast basecatalyzed diastereoisomeric conversion in melt, which provided equimolar mixtures of all four stereoisomers. The coupling of cross-current crystallization and diastereoisomeric conversion could improve yield of crystallization from 29% up to 84%. The purified racemate was further processed by chromatography to isolate finally the most active stereoisomer with 99% purity and total yield of 84%, at a relatively high throughput.

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The major aim of this study was to investigate the effect of ozonation process on the level of oxidative stress markers in blueberry fruit during cold storage (4 °C). Blueberry (Vaccinum corymbosum L.) fruit was ozonated with an ozone concentration of 15 ppm for 30 min, every 12 h for 28 days of storage at 4 °C. The results indicated that ozone treatment activated a defense mechanism against oxidative stress in blueberry fruit. Ozonated fruit was characterized by higher activity of antioxidant enzymes i.e. superoxide dismutase, glutathione peroxidase, and phenylalanine ammonia-lyase than non-ozonated fruit, over the first 21 days of storage. In turn, the level of superoxide anion radical and hydrogen peroxide in ozonated fruit was significantly lower compared with the untreated material. However, after 21 days of storage, ozone treatment contributed to the oxidative modification of protein which could be a reason of decreasing enzymes activity, involved in cell protection against oxidative stress.

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The aim of the study was to identify the effects of ozone treatment reflected by the microbial, mechanical properties and selected chemical parameters during the storage of rhubarb petioles. For this purpose, after they were harvested, rhubarb petioles were treated with gaseous ozone at concentrations of 10 and 100 ppm, for the duration of 5, 15 and 30 min. Subsequently, the plant material was stored at room temperature for 14 days. After this time, the raw material was subjected to a number of chemical and mechanical tests. It was shown that the rhubarb petioles treated with ozone at a rate of 100 ppm for 30 min were characterized by the lowest loss of water content. It was also found that, compared to the control, most samples subjected to ozone treatment presented better mechanical properties, as well as higher oxidative potential and contents of polyphenols and vitamin C. Based on these findings, it was determined that ozone treatment largely increases storage stability of rhubarb.