15E-16 |
Ascorbic acid and dehydroascorbic acid analysis of extracts of acerola cherry Malphigia glabra and a proprietary processed tropical fruit by HPLC |
P. G. DAVID1, K. W. Gellenbeck, D. J. Pusateri, and J. E. Franco. (1) Concentrate Development, Access Business Group, LLC, 19600 6th St., Lakeview, CA 92567-8403 Vitamin C is an umbrella term for ascorbic acid and dehydroascorbic acid. Ascorbic acid is the dominant reduced form of Vitamin C and dehydroascorbic acid is the oxidized form. These are found to be in equilibrium in most food products. This nutrient is found to be abundant in tropical fruits such as acerola cherries. Processed acerola and a proprietary blend were found to contain as much as 25 % to 30% of total Vitamin C, both from ascorbic and dehydroascorbic acid combined. A simple, reliable and rapid HPLC method utilized an indirect measurement of dehydroascorbic acid by subtraction of the measured ascorbic acid concentration from the total ascorbic acid determined after reduction of the dehydroascorbic acid present. The method uses a water soluble, non-volatile and odorless reductant, Tris [(2-carboxyethyl) phosphine hydrochloride], TCEP.HCl as the reducing agent. The TCEP was compared with the commonly used dithiothreitol (DTT) and found to be more stable and effective. The chromatographic conditions applied allowed separation of the majority of the other organic acids: malic, oxalic, fumaric and tartaric acids commonly present in a fruit concentrate, as well as the reducing agent TCEP.HCL.
Session 15E, Nutraceuticals & Functional Foods I
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