Response Surface Methodology (RSM) was used to study the effect
of two variables, sugar level (12-16 °Brix) and acid level (0.3-0.7
% T.A.) on sensory qualities and desirability of blackberry juice
drinks. Three blackberry juice levels (10%, 15%, and 20%) were used
to study the influence of juice flavor on sensory qualities and
desirability of the juice drinks. A trained panel evaluated three
attributes, blackberry flavor, sweetness, and sourness intensities,
of the juice drinks. The consumer panel gave desirability and three
attributes just-right ratings. A Balanced Complete Block Design was
used.
Blackberry flavor intensity was enhanced by sugar level.
Blackberry flavor intensity was enhanced by acid level to a point
about 0.5% T.A., and then decreased. Blackberry flavor intensity was not related to °Brix:acid ratio and was only related to the
sweetness:sourness ratio at the 20% juice level. Sweetness and
sourness intensities increased with increasing sugar and acid
levels. There was a suppression effect of sugar and acid on each
other in the juice drink. The relationships of sweetness, sourness,
and sweetness:sourness ratios to °Brix:acid ratios were all
linear. Desirability rating was related to °Brix:acid and
sweetness:sourness ratios for the 10% and 20% juice levels, for 15%
juice level no association was found. The formula which received the
closest to "just right" ratings and highest overall desirability
rating had in a °Brix of 15.4 and a % titratable acidity of 0.64,
resulting in a °Brix:acid ratio of 24 and a corresponding
sweetness:sourness ratio of slightly less than 1.0. In general, the
15% juice level was the best because of its sugar and acid tolerance
and high desirability. / Graduation date: 1989
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/27240 |
| Date | 08 July 1988 |
| Creators | Perng, Chiou-mey |
| Contributors | McDaniel, Mina R. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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