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TIME‐TEMPERATURE INFLUENCE ON MUSCADINE GRAPE JUICE QUALITY
Author(s) -
FLORA L. F.
Publication year - 1976
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.1365-2621.1976.tb01160.x
Subject(s) - lightness , food science , chemistry , aroma , autoclave , anthocyanin , optics , physics , organic chemistry
Muscadine grape juice was heated in water baths or an autoclave at temperatures of 21, 46, 71, 96 and 121°C for times varying from 0–360 min. The ratio of spectrophotometric absorbances at 520 and 420 nm and tristimulus “a” correlated highly with panel scores (r = 0.982 and 0.953, respectively). Anthocyanin content, A520/A420 ratio, and tristimulus “a” value of juices decreased while lightness (“L”) and tristimulus “b” value increased with prolonged heating. Juice color became unacceptable as A520/A420 dropped below 3.4 or tristimulus “a” dropped below −22. Color damage from heating progressed in a roughly logarithmic fashion from 46°C to 121°C with a Q 10 rate change factor of approximately 1.4. Temperature rather than total heat Input had the greater effect on color changes. Aroma changes preceded unacceptable color changes In the heated juices.