29B-16 |
Effect of processing and storage on antioxidant capacity of honey |
X. H. WANG1, N. Gheldof2, and N. J. Engeseth2. (1) Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, 259 ERML, 1201 W. Gregory, Urbana, IL 61801, (2) Dept. of Food Science & Human Nutrition, Univ. of Illinois, Urbana-Champaign, 259 ERML, 1201 W. Gregory Dr., Urbana, IL 61801 Honey serves as a source of natural antioxidants. Previous antioxidant capacity research focused primarily on processed honeys. Honey is often heated to prevent fermentation by sugar-tolerant yeast and to delay crystallization. The impact of heat treatments and filtration on antioxidant capacity of honey, in general and in storage, is not well understood. The overall objective was to determine the impact of processing on antioxidant capacity of honey during storage, evaluating temperature and containers effects. Processed and raw clover and buckwheat honeys were stored at different temperatures in plastic, clear glass and amber glass bottles for six months. Analysis of initial and stored samples included ORAC assay, total phenolics, HMF, gluconic acid, peroxide accumulation. No significant differences were observed in ORAC values initially between processed and raw clover honey (5.74±0.97 and 6.03±1.34, respectively). After six months, stored clover honeys exhibited lower ORAC values (3.48 to 4.63); however, no treatment or container differences were observed. The ORAC value for raw buckwheat honey (12.68±1.69) was higher initially than that for processed buckwheat honey (8.45±1.55); after storage these differences were not apparent. All stored buckwheat honeys had lower ORAC values after storage (5.73 to 6.97), with no treatment or container differences. Phenolic profiles, characterized by HPLC will be presented. Peroxide accumulation of raw clover and buckwheat honeys was affected by storage temperature and container. HMF was also impacted by storage temperature and container in all clover and buckwheat honeys to different extents. Gluconic acid and total phenolics were not dramatically altered by storage temperature and container. These specific differences will be highlighted. Storage of processed and raw honeys had a complex impact on antioxidant capacity of honeys. Characterization of these alterations assists in the understanding of their antioxidant capacities and thus helps determine optimal processing and storage conditions.
Session 29B, Food Chemistry: Lipids, antioxidants and emulsifiers
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