UNIQUE ORGANIC-ACID PROFILE OF RABBITEYE VS HIGHBUSH BLUEBERRIES

The fruit of six highbush (Vaccinium corymbosum L.) cultivars and eigh t rabbiteye (V. ashei Reade) cultivars and selections were evaluated b y high-performance liquid chromatography for levels of the commonly fo und organic acids, citric, malic, succinic, and quinic. The two cultiv ar groups possessed distinctive patterns of relative organic acid prop ortions that could unambiguously separate pure rabbiteye and highbush clones in a principal component analysis. Highbush clones were charact erized by high citric acid content, with percentages averaging 75% (ra nge 38% to 90%). Succinic acid was the second most plentiful acid, ave raging 17%. In contrast, rabbiteye cultivars and selections contained 10% citric acid, and no clone had >22%. Succinic acid and malic acid w ere found in greater quantities than in highbush, averaging 50 % and 3 4 %, respectively. Analysis of the fruit of seven albino-fruited highb ush selections exhibited a profile similar to standard highbush cultiv ars, but with a citric acid average of <50%, and proportionally greate r amounts of succinic and quinic acids. Given the differences in senso ry quality of these four acids, it is likely that acid partitioning pa tterns can largely account for some of the perceived flavor difference s between rabbiteye and highbush blueberries. Because several current breeding efforts involve hybridization between highbush and rabbiteye blueberries, a consideration of acid composition of breeding parents m ay be worthwhile.