Abstract
Tartaric and citric acid solutions were used to extract anthocyanins from fresh grape skins, in a non continuous process. The type of solvent and concentration were significant factors in the extraction operation, and tartaric acid was more efficient than citric acid in the extraction yield. Comparative trials were conducted using sulphur dioxide and acidified ethanol as solvents. The extraction yields using the optimal tartaric acid solution differed slightly from those obtained with acidified ethanol but were higher than those obtained with sulphur dioxide. Total amounts of polyphenols, proanthocyanidins and flavans were determined in the extracts obtained from the tartaric acid solutions. Solvent concentration was not a significant factor for flavan extraction yield but was highly significant for the extraction of the other compounds. The stability of the anthocyanins was evaluated at four different storage temperatures and atmospheric conditions. The combined effects of low pH of the extract (2.4), low temperature (2.0°C) and modified atmosphere (N 2 ) provided a long shelf-life. Based on the results, a 0.75% tartaric acid solution is recommended for anthocyanin extraction from fresh grape skin, and could substitute the widely used sulphur dioxide.
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Claims 7
Claim · model-written summary
Tartaric acid produced greater anthocyanin extraction yield than citric acid.
Verbatim
e0“The type of solvent and concentration were significant factors in the extraction operation, and tartaric acid was more efficient than citric acid in the extraction yield.”
t0“GRAPE”
Claim · model-written summary
Optimal tartaric acid solution had extraction yield slightly different from acidified ethanol.
Verbatim
e0“The extraction yields using the optimal tartaric acid solution differed slightly from those obtained with acidified ethanol but were higher than those obtained with sulphur dioxide.”
t0“GRAPE”
Claim · model-written summary
Optimal tartaric acid solution yielded more extract than sulphur dioxide.
Verbatim
e0“The extraction yields using the optimal tartaric acid solution differed slightly from those obtained with acidified ethanol but were higher than those obtained with sulphur dioxide.”
t0“GRAPE”
Claim · model-written summary
Solvent concentration was not significant for flavan extraction yield.
Not reportedDirection
Verbatim
e0“Solvent concentration was not a significant factor for flavan extraction yield but was highly significant for the extraction of the other compounds.”
t0“GRAPE”
Claim · model-written summary
Solvent concentration was highly significant for extraction of other compounds.
Not reportedDirection
Verbatim
e0“Solvent concentration was not a significant factor for flavan extraction yield but was highly significant for the extraction of the other compounds.”
t0“GRAPE”
Claim · model-written summary
Low extract pH, low temperature, and modified atmosphere together provided a long shelf-life.
- Taxon
- GRAPEt0
- Treatment
- low pH of the extract (2.4), low temperature (2.0°C) and modified atmosphere (N 2 )e0
- Outcome
- long shelf-lifee0
Not reportedComparatorDirection
Verbatim
e0“The combined effects of low pH of the extract (2.4), low temperature (2.0°C) and modified atmosphere (N 2 ) provided a long shelf-life.”
t0“GRAPE”
Claim · model-written summary
The authors recommend 0.75% tartaric acid solution for anthocyanin extraction from fresh grape skin.
Verbatim
e0“a 0.75% tartaric acid solution is recommended for anthocyanin extraction from fresh grape skin, and could substitute the widely used sulphur dioxide.”
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