Glicerol e açúcares totais em aguardentes de cana de açúcar

Abstract

There is a consensus among enologists that glycerol contributes to the body and sweet taste of wine, by analogy; it was proposed to investigate the presence and role of glycerol in sugar cane spirits. The adapted method for glycerol quantification, which involved the samples derivatization with benzoyl chloride, a further solid phase extraction (SPE) step for samples clean-up and analysis by HPLC-DAD showed good sensitivity (limits of detection and quantification of 0.25 and 0.74 mg L-1 , respectively), 97.5 % of accuracy and 93.5 % of precision. The derivatization reaction between glycerol and benzoyl chloride, studied through liquid chromatography hyphenated to mass spectrometry, was quantitative with esterification of the three hydroxyls of the molecule. Before evaluating the influence of glycerol in cachaça's sweet taste, total sugar concentrations were measured by DNS method (limits of detection and quantification were 37 and 125 mg L-1 , respectively). It was verified that there was no correlation between the contents of glycerol and total sugars with the sweet score, determined by the samples sensory analysis, to the samples which no sugar was added. Based on a triangular test, there was no significant sensory difference between a cachaça without glycerol and another with glycerol concentration up to 35 g L-1. The median glycerol concentration detected in 51 samples of cachaça was 4.3 mg L-1. The median level of total sugars for 59 samples of cachaça without sugar addition was below the limit of quantification. The median level of total sugar for 8 samples of cachaça with sugar addition was 17 g L-1 , expressed as glucose.