5 research outputs found
DETERMINATION OF FREE HYDROCYANIC ACID IN HOMEMADE FRUIT BRANDIES
No full textFruit brandy is a traditional alcoholic beverage widely consumed in the Republic of N. Macedonia and other Balkan countries, produced by distillation of fermented fruits such as plum, apricot, quince and apple, using either homemade or industrial methods. This study aimed to evaluate the safety of 24 homemade fruit brandy samples by determining the content of free hydrocyanic acid (HCN), a potentially toxic compound. HCN is formed during alcoholic fermentation as a result of enzymatic hydrolysis of cyanogenic glycosides naturally present in fruit seeds. The quantification of free HCN was performed spectrophotometrically using König reaction, a colorimetric method based on the formation of cyanogen chloride, which reacts with pyridine and barbituric acid to form a stable pink complex with maximum absorbance at 580 nm. results were recalculated to a 100% v/v ethanol basis to allowed comparison with the EU legal limit of 70 mg/L. All samples were within the permissible safety threshold. The highest HCN concentration were found in apricot and apple brandies (up to 9.81 mg/L), while plum and quince brandies contained significantly lower levels. A moderate correlation was observed between HCN levels and several chemical parameters, including methanol, aldehydes, ethanol, total esters, furfural and fusel alcohols. These results suggest that fruit type, fermentation conditions and the extend of seed contact during the preparation of the fruit mash prior to fermentation play a critical role in HCN formation. This highlights the importance of controlled processing practices to ensure the safety of traditional fruit brandies
INFLUENCE OF THE TYPE OF FERMENTER ON THE CHEMICAL COMPOSITION OF VRANEC AND MERLOT WINES
No full textIn this study, red wines from V. vinifera L. cv. Vranec and Merlot (harvest 2021) have been produced by three different fermentation methods, applying classical, roto and punch down fermenters, in order to study their influence on the wine quality. The chemical parameters that confirm the basic wine quality have been determined, including alcohol, dry extract, specific density, reducing sugars, total and volatile acidity, pH, free and total SO2. The Vranec wines contained relatively higher content of alcohol compared to the Merlot wines, due to the higher content of sugars in the grapes. Wines produced with roto fermenter presented higher values of dry extract and total acidity, compared to the wine produced with classical and punch down fermenters, which confirms that roto fermentation is most suitable for production of complex and structured wines. The alcohol content in all wines ranged from 12.08 to 12.4%, total acidity was between 5.8 to 6.3 g/L and the dry extract from 39 to 45 g/L, while the content of volatile acidity was in range from 0.41 to 0.45 g/L. All wines were dry wines, with content of reducing sugar lower than 4 g/L and all of them were well protected from the oxidation. It was concluded that the type of fermentation affected the wine quality, confirming that applied wine technology is important for production of quality red wines. 
Influence of the type of fermenter on the chemical composition of Vranec and Merlot wines
No full textIn this study, red wines from V. vinifera L. cv. Vranec and Merlot (harvest 2021) have been produced by
three different fermentation methods, applying classical, roto and punch down fermenters, in order to study
their influence on the wine quality. The chemical parameters that confirm the basic wine quality have been
determined, including alcohol, dry extract, specific density, reducing sugars, total and volatile acidity, pH, free
and total SO2
. The Vranec wines contained relatively higher content of alcohol compared to the Merlot wines,
due to the higher content of sugars in the grapes. Wines produced with roto fermenter presented higher values
of dry extract and total acidity, compared to the wine produced with classical and punch down fermenters,
which confirms that roto fermentation is most suitable for production of complex and structured wines. The
alcohol content in all wines ranged from 12.08 to 12.4%, total acidity was between 5.8 to 6.3 g/L and the dry
extract from 39 to 45 g/L, while the content of volatile acidity was in range from 0.41 to 0.45 g/L. All wines
were dry wines, with content of reducing sugar lower than 4 g/L and all of them were well protected from the
oxidation. It was concluded that the type of fermentation affected the wine quality, confirming that applied
wine technology is important for production of quality red wines
Determination of free hydrocyanic acid in homemade fruit brandies
No full textFruit brandy is a traditional alcoholic beverage widely consumed in the Republic of N. Macedonia and other Balkan countries, produced by distillation of fermented fruits such as plum, apricot, quince and apple, using either homemade or industrial technology. This study aimed to evaluate the safety of 24 homemade fruit brandy samples by determining the content of free hydrocyanic acid (HCN), a potentially toxic compound. HCN is formed during alcoholic fermentation as a result of enzymatic hydrolysis of cyanogenic glycosides naturally present in fruit seeds. The quantification of free HCN was performed spectrophotometrically using König reaction, a colorimetric method based on the formation of cyanogen chloride, which reacts with pyridine and barbituric acid to form a stable pink complex with maximum absorbance at 580 nm. Results were recalculated to a 100% v/v ethanol basis to allowed comparison with the EU legal limit of 70 mg/L. All samples were within the permissible safety threshold. The highest HCN concentration was found in apricot and apple brandies (up to 9.81 mg/L), while plum and quince brandies contained significantly lower levels. A moderate correlation was observed between HCN levels and several chemical parameters, including methanol, aldehydes, ethanol, total esters, furfural and fusel alcohols. These results suggest that fruit type, fermentation conditions and the duration of seed contact during the preparation of the fruit mash before the fermentation play a critical role in HCN formation. This highlights the importance of controlled processing practices to ensure the safety of traditional fruit brandies
Influence of different vinification techiques on the phenolic content of Vranec wines
No full textVranec is the most important red grape variety in Macedonia, representing about 70 % of red varieties grown in the country. From this grape variety, high quality red wines are produced, with a characteristic and deep purple colour, rich with phenolic compounds. Phenolic compounds such as anthocyanins, flavonoids and tannins are important constituents of red wine contributing to the taste, color, mouthfeel and quality. They are also associated with the health-promoting properties of red wine. The proportion of the different polyphenols in wine depends on grape variety, maturity, temperature of maceration and fermentation and the type of vinification. In this study, total phenols (TP), total antocianins (TA) and colour parameters of Vitis Vinifera red wines Vranec from vintage 2020, produced in the Republic of N. Macedonia, have been evaluated. The wines have been produced with three winemaking techniques, including classical fermentation, roto process and punch down technique, in order to study and compare the effect of vinification on the phenolic compounds. Total phenols were determined using the Folin-Ciocalteu method and expressed as gallic acid equivalents (GAE, mg/l) [1]. Determination of the total anthocyanins was realized by the method proposed of Di Stefano et al. [2]. The samples were diluted with a solution consisting of 70/30/1 (v/v/v) ethanol/water/HCl (concentrated) and the absorbance was measured at 540 nm. Colour parameters, including color intensity (CI) and hue (H) were determined by direct measurement of the wine absorbance at 420 nm, 520 nm and 620 nm. It was found that the applied vinification technique has an influence of the phenolic content, observing highest content of TP and TA in Vranec wines produced with punch down technique (TP: 1720 mg/l, TA: 254 mg/l) in comparison to Vranec wines produced with a roto technique (TP: 1222 mg/l, TA: 242 mg/l) and classical fermentation (TP: 1198 mg/L, TA: 211 mg/L). It was concluded that the punch down process gave the best results and highest content of total phenols, anthocyanins and colour parameters, in comparison with the other two techniques of vinification
