Effect of Maceration Regime on Phenolic Compound Quantity and Color Quality of Madrasa Wine Samples

Abstract

Along with the well-known "Madrasa" natural wine, the kagor "Shamakhi" is made from the autochthonous red Madrasa grape variety native to the Mountainous Shirvan region of Azerbaijan. The type of wine produced depends on the processing characteristics of this variety, specifically, the mode of maceration of the solid parts of the grape with juice. In this regard, the study of the influence of the maceration period of the mash on the color quality of the wine and the amount of phenolic compounds is relevant and is of scientific and practical importance. The research aimed to explore the influence of the maceration regime of the mash on the amount of phenolic compounds and color indicators in autochthonous Madrasa wine samples. For 96 and 144 hours, maceration was performed at low heat (30ºC), room temperature (20ºC), and cellar temperature (10ºC). The highest amount of phenolic compounds was observed during the maceration of the mash for 144 hours under room conditions (20ºC) and 96 hours under cellar conditions (10ºC).The highest indicator, 88 mg/dm3, in total flavonoids was observed in samples obtained by maceration at 30ºC temperature for 144 hours, and the lowest indicator, 62 mg/dm3 under room conditions by maceration for 144 hours. In both processing methods, 7 phenolic acids were detected. Compared to others, the amount of catechin, gallic acid, and epicatechin was more. The amount of catechin varied from 34.90 to 39.80, galacturonic acid from 12.60 to 16.00, and epicatechin from 5.01 to 6.91 mg/dm3. The amount of other four phenolic acids were found to be many times less abundant. In addition to natural adhesives such as bentonite and gelatin, polyvinylpolypyrrolidone (PVPP) was used to remove polyphenols, and the best results were obtained in this case. The total amount of phenolic compounds in the initial wine sample was 520 mg/dm³ and anthocyanins 83 mg/dm³, while those indicators were reduced by 14.4% and 20.5%, respectively, when treated with PVPP. We can note that bentonite is the second adhesive according to the degree of effect on phenolic compounds.