ARS | Publication request: Proximate and polyphenolic characterization of cranberry pomace

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 19, 2010
Publication Date: December 18, 2009
Citation: White, B.L., Howard, L.R., Prior, R.L. 2009. Proximate and polyphenolic characterization of cranberry pomace. Journal of Agricultural and Food Chemistry. 58(7):4030-4036.

Interpretive Summary: Cranberry pomace is the by-product of the cranberry processing industry and is composed of skin, seeds, and stems, which remain after the fruit has been pressed for juice or prepared for canning. Applications for cranberry pomace are limited. Its low protein content makes it unsuitable for animal feeds, and its low pH presents problems when it is disposed of in the soil. Cranberries are recognized for their ability to prevent urinary tract infections which has been attributed to the presence of polyphenolic compounds, notably procyanidins. These compounds are found primarily in the seeds and skins of the fruit; thus, many are retained in the pomace. The purpose of this study was to determine the amounts of moisture, protein, ash, and fat in cranberry pomace and to identify and quantify polyphenolic compounds contained in dried cranberry pomace. Cranberry pomace contained numerous polyphenolic compounds including 6 anthocyanins, 13 flavonols, and the aglycones forms of myricetin and quercetin were prominent. Procyanidins were identified, the most abundant being a dimmer with A-type linkage in its structure. Cranberry pomace should be explored as a good source of polyphenolic compounds.

Technical Abstract: The proximate composition and identification and quantification of polyphenolic compounds in dried cranberry pomace were determined. Proximate analysis was conducted based on AOAC methods for moisture, protein, fat, and ash. Total carbohydrates were determined by the difference method. Polyphenolic compounds were identified and quantified by HPLC-ESI-MS. The composition of dried cranberry pomace was 4.5% moisture, 2.2% protein, 12.0% fat, 80.1% carbohydrate, and 1.1% ash. It contained six anthocyanins (111.5 mg/100 g DW) including derivatives of cyanidin and peonidin. Thirteen flavonols were identified (256.6 mg/100 g DW), and the aglycones myricetin (52.2 mg/100 g DW) and quercetin (138.6 mg/100 g DW) were the most prominent. Procyanidins with degrees of polymerization (DP) of 1 – 6 were identified (167.3 mg/100 g DW), the most abundant being an A-type of DP2 (82.6 mg/100 g DW).