|Khanal, Ramesh -|
|Howard, Luke -|
|Prior, Ronald -|
Submitted to: Food Research International
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 28, 2010
Publication Date: June 28, 2010
Citation: Khanal, R., Howard, L., Prior, R.L. 2010. Effect of heating on the stability of grape and blueberry pomace procyanidins and total anthocyanins. Food Research International. 43(5):1464-1469. Interpretive Summary: Fruit by-products are rich sources of procyanidins and anthocyanins known for potential health benefits. Pomace from blueberries and grapes, which is the material remaining after the processing of fruits for juice production, was used in this study to determine effects of heating and duration of extraction on some of the phytochemicals. Heating at temperatures above 40 C for 72 hours caused a loss of anthocyanins and procyanidins extracted from both blueberry and grape pomace. Results from this study can be used in developing extraction methods to recover phytochemicals in blueberry and grape pomace for use in dietary supplements.
Technical Abstract: Fruit by-products are rich sources of procyanidins and anthocyanins known for potential health benefits. Freeze dried blueberry pomace and grape pomace were heated in a forced air oven at 40, 60, 105, and 125 °C for 72, 48, 16, and 8 h respectively, to study the stability of procyanidins and total anthocyanins. Heating decreased procyanidin concentrations significantly (p < 0.05) in both blueberry and grape pomace, except when heated at 40 °C for 72 h. Reduction occurred when heated at 60 °C or above with no further reduction when heating temperature increased from 105 to 125 °C. Heating also affected total anthocyanin contents in both grape and blueberry pomace with no significant (p > 0.05) loss when heated at 40 °C. Total anthocyanin loss was highest at 125 °C for both blueberry (52%) and grape pomace (70%). Results suggested that while heating at lower temperatures for up to 3 days may not be detrimental, heating at higher temperatures for more than 8 h results in considerable loss of both the compounds.