45F-14 |
Anthocyanins and polyphenolics of fresh and processed cherries |
A. CHAOVANALIKIT and R. E. Wrolstad. Dept. of Food Science & Technology, Oregon State Univ., 100 Wiegand Hall, Corvallis, OR 97331-6602 Investigators have shown that cherries have high levels of polyphenolics and antioxidant activity, which may provide health benefit. In a previous study, we compared the total anthocyanins, total phenolics and antioxidant properties for sweet and sour cherries and how the levels were affected by freezing, canning, and brining. The purpose of this investigation was to address how individual anthocyanins and polyphenolics are affected. Our objectives were to characterize and determine the distribution of individual anthocyanins and polyphenolics in peel, flesh and pit. We also wanted to determine how they were affected by frozen storage, canning and sulfite-brining. Aqueous extracts, which had been stored at –70°C were available from the previous study. Samples included extracts of peel, flesh, and pit of Bing, Royal Anne, Rainier, and Montmorency cherries; frozen Bing cherries which had been stored for six months; canned Bing cherries; Royal Anne and Bing cherries which had been brined in sulfite brine. Solid phase extraction (C 18 Sep-Pak) was used to separate anthocyanin and polyphenolic fractions. Individual anthocyanins and polyphenolics were qualitatively and quantitatively analyzed using HPLC with UV-visible diode array detection. Electrospray mass-spectroscopy was used for identification. All cherry cultivars contained the anthocyanins: cyanidin-3-glucoside, cyanidin-3-rutinoside and peonidin-3-rutinoside, while Montmorency contained in addition cyanidin-3-sophoroside and cyanidin-3-glucosylrutinoside. The major cherry polyphenolics were chlorogenic acid and its isomer, p-coumaroylquinic acid, quercetin-3-glucoside, quercetin-3-rutinoside, catechin and epicatechin while procyanidins were additionally found only in Montmorency. The skin and flesh were similar qualitatively. The skin contained higher amounts of chlorogenic acid derivatives and quercetin glycosides. Quercetin glycosides were more stable to freezing and canning than chlorogenic acid. All polyphenolics were transformed to unidentified compounds during the brining. Processing wastes, such as spent cherry brine and cherry pits, are potential sources for nutraceuticals and natural colorants. Processing has less impact on polyphenolics than anthocyanins.
Session 45F, Fruit & Vegetable Products: Fruits (Fresh)
|