Original scientific paper
Aroma profiles and sensory evaluation of yogurt during storage
Mirjana Hruškar
; Prehrambeno-biotehnološki fakultet, Pierottijeva 6, 10000 Zagreb
Nada Vahčić
Milana Ritz
Abstract
It is known that more than 100 chemical compounds have been isolated from yogurt and related milk products but only a few (acetaldehyde, ethanol, aceton, diacetyl and butanon-2) have a high impact on the desired product flavour. The concentration of these typical flavour compounds changed during storage depending on duration and temperature in depot. In this article six commercial brands of plain yogurt were stored within 10 days on two different temperatures and every two days changes in acetaldehyde, diacetyl and ethanol were established. At the same time sensory evaluation was carried out as well. Acetaldehyde and ethanol concentration was determined using aldehyde dehydrogenase and alcohol dehydrogenase method. Diacetyl was measured according to Hill's modification of colorimetric method. A five member panel, performed sensory analysis using scoring system with weighted factors in the 20-points' scale. Expert panel's ratings were regressed against concentrations of aroma compounds for both temperature levels and linear relationship among them were determined. The most pronounced relationship expressed as correlation coefficients (r) between expert panel's ratings and concentrations of individual compounds was observed with ethanol (r=0.996) in yogurt sample stored at +4°C. Coefficients of correlation were generally high (from 0.824 to -0.996) and consequently very accurately predicting equations were obtained using regression analysis.
Keywords
aroma compounds; acetaldehyde; diacetyl; ethanol; sensory evaluation; correlation
Hrčak ID:
95051
URI
Publication date:
4.9.1995.
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