Electrochemical studies on the stability and corrosion resistance of two austenitic stainless steels for soft drinks containers

Austenitic stainless steel alloys are used in different food industry applications, including the preparation and storage of acidified carbonated soft drinks. Yet, austenitic stainless steels are not inert materials in contact with these drinks, and eventual modifications of these alloys must be investigated. Three carbonated soft drinks were investigated as for their effect on the stability of FeCrNi and FeCrNiMo alloys using two electrochemical techniques, namely linear potentiodynamic polarization (LPP) and electrochemical impedance spectroscopy (EIS), at 25 ºC. The high corrosion resistance of the austenitic stainless steel alloys in the soft drinks was provided by the formation of a rather stable passive film formed by metal oxides. Also, the electrochemical behaviour was related to an inhibitory action by caffeine as evidenced using potentiodynamic polarization and electrochemical impedance spectroscopy methods, with good correlations between the

Analysis of aflatoxins in rustically wines from eastern Romania using the direct real time method (DART)

Romania has a long tradition regarding the production of wine rustically or household products. Each householder has the possibility for making its own wine from its own grape vines. Most of them are made and kept using almost no interventions or treatments no corrections or added substances, which could protect them from eventual diseases, which may appear during the winemaking process. The grapes are collected manually by each family alone and it can be called is itself a ritual specific to the each area and a symbol of autumn. In this context, several samples of wine were collected from households located in five Romania eastern counties (Iaşi, Vaslui, Galaţi, Brăila, Ialomiţa and Tulcea). The samples were neither filtered, nor treated against the developing secondary fermentations. This fact increases the risk of infestation with mycotoxins. Twenty samples belonging to the aforementioned regions were analysed using the direct real time method (DART). This method is very fast and does not require any prior preparation of the samples. The goal was to identify the aflatoxins B1, B2, G1 and G2 that are known to be frequently present in wines. From the total of the analysed samples, in four of them it was detected a concentration greater than 20 μg/kg

Analysis of aflatoxins in rustically wines from eastern Romania using the direct real time method (DART)

Romania has a long tradition regarding the production of wine rustically or household products. Each householder has the possibility for making its own wine from its own grape vines. Most of them are made and kept using almost no interventions or treatments no corrections or added substances, which could protect them from eventual diseases, which may appear during the winemaking process. The grapes are collected manually by each family alone and it can be called is itself a ritual specific to the each area and a symbol of autumn. In this context, several samples of wine were collected from households located in five Romania eastern counties (Iaşi, Vaslui, Galaţi, Brăila, Ialomiţa and Tulcea). The samples were neither filtered, nor treated against the developing secondary fermentations. This fact increases the risk of infestation with mycotoxins. Twenty samples belonging to the aforementioned regions were analysed using the direct real time method (DART). This method is very fast and does not require any prior preparation of the samples. The goal was to identify the aflatoxins B1, B2, G1 and G2 that are known to be frequently present in wines. From the total of the analysed samples, in four of them it was detected a concentration greater than 20 μg/kg

Quantification of toxic metals during different winemaking stages

Heavy metals in beverages can constitute serious problems to human health. Consumption of wine may contribute to the daily dietary intake of pollutants, especially of toxic (heavy) metals. These compounds are also known as priority pollutants due to their potential toxic effects, if concentrations are not kept under allowable limits. Many characteristics such as: quality, origin, aroma and health safety of wine are influenced by environmental and anthropogenic factors. Hence, the contamination of wine by priority pollutants may occur at different stages of vine-growing, due to the application of agricultural chemicals, or at different stage of winemaking and ageing, because of the extended contact of wine with winemaking equipment materials (aluminium, brass, glass, stainless steel and wood, etc.), or chemicals used for cleaning and sanitation. The aim of this study is to identify and quantify the heavy metal ions from red wines. A particular focus was attributed to Zn and Cd from destemming-pressing-filtration-bottling stages in Fetească neagră grape variety from Cotnari vine growing region of Romania. Results indicated that heavy metals were linked to diverse Zn and Cd sources and complexes during the winemaking processes. Concentration of Zn and Cd were generally higher in must than in wine, although heavy metals concentrations were lower than the limits recommended by the International Organization of Vine and Wine for human health safety

Evaluation of byproducts from the wine-making industry by identification of bioactive compounds

Byproducts obtained after wine production constitute an important source for the extraction of antioxidant compounds. Phenolic compounds showed a wide spectrum of biological actions for the human health, often associated with neuroprotective, cardioprotective, antimicrobial and other health-related effects. The aim of the present study was to determine the phenolic compounds content and antioxidant activity of grape marc from selected grapes from Iaşi vineyard. The total phenolic content of the extracts was measured using the Folin-Ciocâlteu method, with some modifications. The DPPH (2,2-diphenyl-1-picrylhydrazyl) assay was used to evaluate radical scavenging activity, by bleaching of purple methanolic solution of the stable radical. All extracts were able to reduce DPPH radical with different degrees of scavenging activity. The highest radical scavenging activity was determined for the extract obtained from Merlot and Fetească Neagră (98.142 μg/mL, and 115.78 μg/mL respectively), with positive correlation between scavenging activity on DPPH and total phenolic content. The total phenolic content varied among the analysed extracts, with a higher concentration in extracts obtained from Merlot, Fetească Neagră and Traminer rosé (2.42 GAE/mL, 1.45 GAE/mL and 1.24 GAE/mL respectively), followed by Sauvignon Blanc and Muscat Ottonel extracts with comparable amounts. The FRAP (ferric reducing antioxidant power) method relies on the color change of a complex with Fe+3 ion of the 2,4,6-tri(2-pyridyl) – 1,3,5-triazine (TPTZ) radical due to the reduction of the ferric ion to the ferrous iron (Fe+2) in this complex. The highest radical scavenging activity was determined in the extract obtained from Merlot and Fetească Neagră (1164.22 μM Trolox/100 mL and 782.09 μM Trolox/100 mL respectively), a positive correlation between scavenging activity determined by FRAP method and total phenolic content being observed.Statistical analysis showed a close relationship between content of phenolic compounds and antioxidant capacity, the marc of Merlot and Fetească Neagră had the highest contents of anthocyanins. The results suggested that grape pomace may be exploited as antioxindant source

Influence of enzymatic treatments on white wine composition

Most biochemical reactions involved in the wine-making process are catalyzed by enzymes. The use of enzymes of exogenous origin in wine production is due to the numerous technological and economical advantages demonstrated over time in the winemaking process. Understanding the important role played by enzymes in wine making technology contributes to the development of optimization strategies for the production process to improve the final quality of the wine. In order to accomplish this study, the influence of five oenological preparations with pectolytic and β-glucosidases enzymes types on the volatile compounds of white wines obtained from Fetească regală variety was analyzed by monitoring their evolution during the alcoholic fermentation to the final product. Wine samples have been physically and chemically analysed (pH, acidity, alcoholic strength, density, malic acid, lactic acid, sugar content, SO2, total dry extract and non-reducing extract) according to OIV Standards. Separation and identification of flavor compounds was performed using an Agilent 7890 gas chromatograph coupled to a 5975 C inert XL EI/CI MSD spectrophotometer. The organoleptic evaluation of wines was made according to a wide range of sensory descriptors. An important evolution of volatile compounds during fermentation was observed, depending on the type of enzyme administered, compared to the control sample. Enzymatic treatments did not significantly affect the physico-chemical composition of the wines obtained. The chromatic parameters of the wine samples varied according to the type of enzyme applied. The results of the study showed a significant influence of the enzymes on the organoleptic characteristics of the wines. Therefore, the aromatic quality of a wine is directly proportional to the chemical composition of the grapes and to the technology

Antioxidant and antimicrobial effects of grape pomace extracts

The use of antioxidants and antibacterials in food industry has become increasingly necessary to ensure the high quality of food. Grape pomace is the main by-product of winemaking industry that concentrates bioactive metabolites with more studied antioxidant activity and possible antibacterial activity. The grape pomace contains fragmented skin, broken cells, pulp remains, stalks and seeds with high amount of phenolic compounds due to their poor extraction during the winemaking process. Anthocyanins, catechins, flavonol glycosides, phenolic acids, alcohols and stilbenes have been identified among the compounds present in grape pomace. In this study, antibacterial activity against different pathogens (Escherichia coli ATCC 25922, Candida albicansATCC 90028, Pseudomonas aeruginosa ATCC 27853 and Staphylococcus aureus ATCC 25923) was evaluated and the relation with polyphenols content and antioxidant activity of grape pomace from selected grapes from Iaşi vineyard was studied. The grape pomace samples were obtained after the fermentation process from the 2017 harvest of Sauvignon Blanc, Traminer, Busuioacă de Bohotin, Cabernet Sauvignon, Merlot, Fetească Neagră and Fetească Regală grape varieties. The antioxidant properties were evaluated using the DPPH method, FRAP assay and Folin Ciocalteu method. The content of resveratrol was quantified using an HPLC method. Samples with antioxidant activity showed the highest phenolics content. This study reveals that grape pomace is a potential source of natural antioxidant agents. The pomace extracts were tested to establish the effects on Gram-positive and Gram-negative bacteria. The analysed samples exhibited insignificant antibacterial activity and the method requires optimization. Grape marc represents an important source of resveratrol and other bioactive compounds that could be a valuable source of antioxidants for further utilization in food and pharmaceutical industry