Influenţa negativă a temperaturii asupra compuşilor de aromă din vin

The aromatic profile of wine is offered by the variety of volatile chemical compounds, especially esters, alcohols, carboxylic acids and nitrogen compounds.These substancescan determine different aromas depending on concentration. One of the very important factors in forming aromasis the fermentation temperature whose which has anoptimal value between 15-17 °C. This study evaluated winessamples which were fermented without temperature control, reaching an average temperature inbetween 21-24°C. Following this experiment it was observed how the compounds that give floral and fruity aromas can give unwanted sensations in high concentrations. At the same time, several esters of the fatty acids were observe which give a heavy smell and cause the sensation of fats. The aromatic profile of the sample which was fermented at higher temperature is more affected, even becoming repulsive once the temperature is rising

Evaluarea compuşilor fenolici prin metode spectrometrice ecologice

The study aimed to analyse phenolic compounds from wine samples using “ecological” spectrometric methods (low consumption of chemical reagents) comparing a traditional UV-VIS spectrophotometer to a microplate reader spectrometer. Different experimental wine samples were obtained using active charcoal, gelatine and anionic resins. The used wines were produced from Fetească neagră grapes harvested at full maturity from Şuletea region, Vaslui County, with approx. 290 g/L concentration in fermenting substances.A total of 43 samples were analysed. The microplate reader was shown to be an extremely efficient and economic tool for analysing wines as the linearity of the used methods was shown to be comparative between devices. The time required for analysis is considerably reduced in this case and the versatility of the method allows better statistical evaluation of parameters within the limit of 10% of the relevant significance

Metode de evaluare a potenţialului în micotoxine din industria oenologică

Recent studies have confirmed that mycotoxins such as aflatoxins are present in foods and are responsible for most cases of liver cancer and modification of human DNA. These forms on foods where conditions of handling, transportation and storage promotemould growth, such as high temperature and humidity. There are four types of aflatoxins in food isolates (B1, B2, G1, G2) with B1 the most toxic. The study aims to assess methods of analysis for these important substances in human health and quality of wine. The maximum authorized concentration of this class of mycotoxins is 2 ppb. The determination of aflatoxins in the wine can be achieved by high performance liquid chromatography, thin layer chromatography, gas chromatography and ELISA. The purpose of this work is to stimulate risk awareness to the improper selection of harvest quality and the need to invest in the product safety

Rapid assessment of mycotoxins in wine by on-line SPE-UHPLC-FLD

According to the latest statistics, grapes are one of the largest fruit crops worldwide. In this regard, it is important to consider all factors influencing quality of grapes and wine. In the last years, scientist focused on the study of mycotoxins that can influence the quality of wine. It is considered that toxins produced by moulds, causing significant economic losses, affect approximately one quarter of the world grape production. If the selective sorting of infected grapes is not done adequately, wine will present a major risk to consumers, mycotoxins being considered by the “International Agency for Cancer Research” a carcinogenic compound. The main mycotoxins monitored in this study come from Aspergillus sp., and are represented by aflatoxins B1, B2, G1, G2 and ochratoxin A. This study purpose is to develop a faster method for the analysis of mycotoxins, in order to increase rapidity and efficiency for the evaluation of the degree of infestation in wine. The purposed method is using an on-line large volume injection coupled to pre-concentration of sample (SPE) which is directly transfer to the ultra-high-pressure liquid chromatography (UHPLC) column for separation and the detection by means of the fluorescence detector (FLD). As the maximum tolerated level for mycotoxins in wines is 2 ppm, this method is able to detect under this limits of quantification with RSD below 2%

Rapid assessment of mycotoxins in wine by on-line SPE-UHPLC-FLD

According to the latest statistics, grapes are one of the largest fruit crops worldwide. In this regard, it is important to consider all factors influencing quality of grapes and wine. In the last years, scientist focused on the study of mycotoxins that can influence the quality of wine. It is considered that toxins produced by moulds, causing significant economic losses, affect approximately one quarter of the world grape production. If the selective sorting of infected grapes is not done adequately, wine will present a major risk to consumers, mycotoxins being considered by the “International Agency for Cancer Research” a carcinogenic compound. The main mycotoxins monitored in this study come from Aspergillus sp., and are represented by aflatoxins B1, B2, G1, G2 and ochratoxin A. This study purpose is to develop a faster method for the analysis of mycotoxins, in order to increase rapidity and efficiency for the evaluation of the degree of infestation in wine. The purposed method is using an on-line large volume injection coupled to pre-concentration of sample (SPE) which is directly transfer to the ultra-high-pressure liquid chromatography (UHPLC) column for separation and the detection by means of the fluorescence detector (FLD). As the maximum tolerated level for mycotoxins in wines is 2 ppm, this method is able to detect under this limits of quantification with RSD below 2%

The Effect of Extraction Conditions on the Barrier and Mechanical Properties of Kefiran Films

Kefiran is an exopolysaccharide classified as a heteropolysaccharide comprising glucose and galactose in equimolar quantities, and it is classified as a water-soluble glucogalactan. This work aimed to investigate the effect of different extraction conditions of kefiran on the structural and physical properties of the edible films obtained. Fourier-transform infrared spectroscopy and scanning electron microscopy were performed, together with a determinations of moisture content, solubility, water vapor permeability and degree of swelling. The kefiran films presented values of the water vapor permeability between 0.93 and 4.38 × 10−11 g/m.s.Pa. These results can be attributed to the development of a more compact structure, where glycerol had no power to increase the free volume and the water vapor diffusion through their structure. The possible conformational changes in the kefiran film structure, due to the interspersing of the plasticizers and water molecules that they absorb, could be the reason for producing flexible kefiran films in the case of using glycerol as a plasticizer at 7.5% w/w. Moreover, it was observed that the extraction conditions are a significant factor in the properties of these films and their food technology applications

Succinic acid – A run-through of the latest perspectives of production from renewable biomass

Succinic acid (SA) production is continuously rising, as its applications in diverse end-product generation are getting broader and more expansive. SA is an eco-friendly bulk product that acts as a valuable intermediate in different processes and might substitute other petrochemical-based products due to the inner capacity of microbes to biosynthesize it. Moreover, large amounts of SA can be obtained through biotechnological ways starting from renewable resources, imprinting at the same time the concept of a circular economy. In this context, the target of the present review paper is to bring an overview of SA market demands, production, biotechnological approaches, new strategies of production, and last but not least, the possible limitations and the latest perspectives in terms of natural biosynthesis of SA