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DIFFERENTIAL SCANNING CALORIMETRY (DSC) STUDIES ON THE STRUCTURES OF WATER‐ETHANOL MIXTURES AND AGED WHISKEY
Author(s) -
KOGA KUNIMASA,
YOSHIZUMI HAJIME
Publication year - 1977
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1365-2621.1977.tb14462.x
Subject(s) - differential scanning calorimetry , endotherm , ethanol , chemistry , melting point , calorimetry , dehydration , analytical chemistry (journal) , chromatography , thermodynamics , organic chemistry , biochemistry , physics
DSC measurements of water‐ethanol mixture in various ethanol concentrations were made in the temperature range from ‐160°C to +10°C. In the entire concentration range, eight peaks (peaks 1–8) were observed. The heat of every peak (J/g) remarkably changed at 40(V/V)% and 60% ethanol concentrations. At 40% ethanol concentration, the heat of peak 3 (endotherm at ‐58°C) was at its maximum, while the heat of peak 6 (exotherm at ‐100°C) was at its minimum. The melting point of ethanol in the mixture was ‐74°C when the concentration was below 40%, and ‐62°C when the concentration was above 40%. At 60%, the heats of peak 2 (exotherm at ‐52°C) and peak 6 were at their maxima. It is, therefore, considered that structural alterations of the mixture occur at 40% and 60%. Peak 3 was ascribed to the melting of strongly‐interacted water and ethanol. Similar thermogram patterns were obtamed by the DSC measurements of barley malt whiskey aged for 7 yr in a new oak barrel which was burnt brown and had previously been treated with sherry. However, by comparing the heat of peak 3 of whiskey with that of the mixture, it was known that the interaction between water and ethanol in the aged whiskey was more stronger than that in the water‐ethanol mixture.