The effect of cultivation practices on fruit quality and antioxidant capacity in highbush blueberries var. Bluecrop (Vaccinium corymbosum L.) was evaluated from random samples of commercial late harvest fields in New Jersey. Results from this study showed that blueberry fruit grown from organic culture yielded significantly higher sugars (fructose and glucose), malic acid, total phenolics, total anthocyanins, and antioxidant activity (ORAC) than fruit from the conventional culture. In organically cultured fruit, the average values for the ORAC, total anthocyanins, and total phenolic content were 46.14 micromol of Trolox (TE)/g of fresh weight (fwt), 131.2 mg/100 g of fwt, and 319.3 mg/100 g of fwt, respectively. In conventionally cultured fruit, the average values for the ORAC, total anthocyanin, and total phenol content were 30.8 micromol of TE/g of fwt, 82.4 mg/100 g of fwt, and 190.3 mg/100 g of fwt, respectively. The organic culture also produced fruit with higher contents of myricetin 3-arabinoside, quercetin 3-glucoside, delphinidin 3-galactoside, delphinidin 3-glucoside, delphinidin 3-arabinoside, petunidin 3-galactoside, petunidin 3-glucoside, and malvidin 3-arabinoside than conventional culture. There was a significant correlation between the ORAC values and total phenolics and total anthocyanins. These results indicate that even though there were variations in phytonutrient content among individual farms within each cultural system, significant differences between two cultivation practices were evident.

High-performance liquid chromatography coupled with ultraviolet and electrospray ionization mass spectrometry (HPLC/UV/ESI-MSD) was applied to the study of isoflavones in both Edamame and Tofu soy varieties, from which the immature fresh soybeans or the mature soybean seeds are consumed, respectively. Positive atmospheric pressure interface (API) MS and MS/MS were used to provide molecular mass information and led to the identification of a total 16 isoflavones, including three aglycones, three glycosides, two glycoside acetates, and eight glycoside malonates. The major isoflavones in soybean seeds were daidzein and genistein glycoside and their malonate conjugates. Trace levels of daidzein and genistein acetyl glycosides were found only in the mature dry soybean seeds. To facilitate quantitative analysis, acid hydrolysis during extraction of soy samples was selected to convert the various phytoestrogen conjugates into their respective isoflavone aglycones, allowing accurate quantitation of total phytoestrogens as aglycones. On the basis of HPLC combined with UV and MS detection, all three targeted soy isoflavone aglycones, daidzein, genistein and glycitein in hydrolyzed extracts were successfully quantified within 25 min with formononetin used as the internal standard. The standard curves of UV detection were fitted in the range of 14.16-29000 ng/mL for daidzein, 15.38-31500 ng/mL for genistein, and 11.72-24000 ng/mL for glycitein. For MS detection, the standard curves were established in the range of 3.54-1812.5 ng/mL for daidzein, 3.85-1968.75 ng/mL for genistein, and 2.93-1500 ng/mL for glycitein. Good linearities (r(2) > 0.999 for UV and r(2) > 0.99 for MS) for standard curves were achieved for each isoflavone. The accuracy and precision (RSD) were within 10% for UV detection and 15% for MS detection (n = 10). Using this method, the phytoestrogen levels of total isoflavone aglycones from 30 soybean seed varieties were then evaluated for confirmation of the technique. Total isoflavones ranged across the varieties from 0.02 to 0.12% in the Edamame varieties, which are harvested while the seeds are still immature, and from 0.16 to 0.25% in Tofu varieties, harvested when the seeds are physiologically mature. While the literature has focused on the isoflavone content of soy products and processing soy, this report provides a reliable analytical technique for screening of authenticated fresh immature Edamame soybeans and Tofu soybeans.

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