Location: Arkansas Children's Nutrition CenterTitle: Processing and storage effects on monomeric anthocyanins, percent polymeric color and antioxidant capacity of processed black raspberry products Author
Submitted to: Journal of Food Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/25/2008
Publication Date: 7/15/2008
Citation: Hager, A., Howard, L.R., Prior, R.L., Brownmiller, C.R. Processing and storage effects on monomeric anthocyanins, percent polymeric color and antioxidant capacity of processed black raspberry products. Journal of Food Science. 73(6):H134-H140. Interpretive Summary: Black raspberries, like other berries, are not only available fresh, but are also available for consumption in frozen and thermally processed (jellies, jams, juices, and purees) forms. Processing methods varying in the number of processing steps, and heating temperature and duration can markedly affect the concentrations of many of the health-promoting compounds found in berries. The purpose of this study was to evaluate the effects of various processing methods such as freezing, canning, and juicing on concentrations of some of the antioxidant components in black raspberries. Results from the study demonstrated that methods involving heat processing result in significant losses of bioactive components, and storage at room temperature following processing also resulted in significant losses of several of the components. Freezing was an effective way to preserve bioactive components.
Technical Abstract: This study evaluated the effects of processing and 6 mo of storage on total monomeric anthocyanins, percent polymeric color, and antioxidant capacity of black raspberries that were individually quick-frozen (IQF), canned-in-syrup, canned-in-water, pureed, and juiced (clarified and nonclarified). Total monomeric anthocyanins, percent polymeric color, and ORAC(FL) were determined 1 d postprocessing and after 1, 3, and 6 mo of storage. Thermal processing resulted in marked losses in total anthocyanins ranging from 37% in puree to 69% to 73% in nonclarified and clarified juices, respectively, but only the juices showed substantial losses (38% to 41%) in ORAC(FL). Storage at 25 degrees C of all thermally processed products resulted in dramatic losses in total anthocyanins ranging from 49% in canned-in-syrup to 75% in clarified juices. This coincided with marked increases in percent polymeric color values of these products over the 6-mo storage. ORAC(FL) values showed little change during storage, indicating that the formation of polymers compensated for the loss of antioxidant capacity due to anthocyanin degradation. Total anthocyanins and ORACFL of IQF berries were well retained during long-term storage at -20 degrees C.