Article

Multi-laboratory validation of a standard method for quantifying proanthocyanidins in cranberry powders.

USDA-ARS, Arkansas Children's Nutrition Center, Little Rock, AR 72202, USA.
Journal of the Science of Food and Agriculture (Impact Factor: 1.88). 07/2010; 90(9):1473-8. DOI: 10.1002/jsfa.3966
Source: PubMed

ABSTRACT The objective of this study was to validate an improved 4-dimethylaminocinnamaldehyde (DMAC) colorimetric method using a commercially available standard (procyanidin A2), for the standard method for quantification of proanthocyanidins (PACs) in cranberry powders, in order to establish dosage guidelines for the uropathogenic bacterial anti-adhesion effect of cranberry.
Commercially available cranberry samples were obtained (five from U.S. sources and six from European sources) for PAC quantification in five different analytical laboratories. Each laboratory extracted and analyzed the samples using the improved DMAC method. Within-laboratory variation (mean +/- SD) was 4.1 +/- 1.7% RSD (range, 2.3-6.1% RSD) and the between laboratory variability was 16.9 +/- 8.5% RSD (range, 8-32% RSD). For comparative purposes, the cranberry samples were alternatively quantified using weights of extracted PACs (gravimetric). The correlation coefficient between the two methods was 0.989.
This improved DMAC method provides a simple, robust and relatively specific spectrophotometric assay for total PACs in cranberry samples using commercially available procyanidin A2 dimer as a standard. DMAC is most useful within a given type of food such as cranberries, but may not be appropriate for comparing concentrations across different food types, particularly in those cases where large differences exist among the relative amounts of each oligomer and polymer.

1 Follower
 · 
473 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The objectives of this work were to characterize polyphenols and α- and γ-tocopherols in several commercial cultivars of Elaeagnus umbellate (autumn olive) berry. Acidic aqueous acetone extraction yielded the highest total phenol recovery, ranging from 190 to 275 mg gallic acid equivalents (GAE)/100 g fresh weight among berry cultivars. Berries were found to contain proanthocyanidins by reaction with 4-(dimethylamino)cinnamaldehyde. Normal phase HPLC analysis confirmed that the total proanthocyanidin content of berries ranged from 68 to 225 catechin equivalents/100 g dry weight. Proanthocyanidins were composed of 64 to 89% polymers with degree of polymerization >10, with lesser amounts of monomers through 5-mers. Total α- and γ-tocopherol ranged between 9 and 23 mg/100 g oil. The ratio of α- to γ-tocopherol varied from ~3:1 to 10:1 among autumn olive cultivars. Thus, the presence of highly polymerized proanthocyanidins and tocopherols should be considered in formulating functional foods with autumn olive berry.
    Journal of Functional Foods 06/2015; 16:305-314. DOI:10.1016/j.jff.2015.04.028 · 4.48 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Haskap (Lonicera caerulea L.) berries have long been used for their health promoting properties against chronic conditions. The current study investigated the effect of Canadian haskap berry extracts on pro-inflammatory cytokines using a human monocytic cell line THP-1 derived macrophages stimulated by lipopolysaccharide. Methanol extracts of haskap from different growing locations in Canada were prepared and characterized for their total phenolic profile using colorimetric assays and liquid chromatography—Mass spectrometry (UPLC-MS/MS). Human THP-1 monocytes were seeded in 24-well plates (5 × 10 5 /well) and treated with phorbol 12-myristate 13-acetate (PMA, 0.1 ȝg/mL) for 48 h to induce macrophage differentiation. After 48 h, the differentiated macrophages were washed with Hank's buffer and treated with various concentrations of test compounds for 4 h, followed by the lipopolysaccharide (LPS)-stimulation (18 h). Borealis cultivar showed the highest phenolic content, flavonoid content and anthocyanin content (p < 0.05). A negative correlation existed between the polyphenol concentration of the extracts and pro-inflammatory cytokines: Interleukin-6 (IL-6), tumour necrosis factor-alpha (TNF-Į), prostaglandin (PGE2), and cyclooxygenase-2 (COX-2) enzyme. Borealis exhibited comparable anti-inflammatory OPEN ACCESS Biomolecules 2015, 5 1080 effects to COX inhibitory drug, diclofenac. The results showed that haskap berry polyphenols has the potential to act as an effective inflammation inhibitor.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: This study presents the evaluation of an emergent co-product generated during the production of jaboticaba juice by steam drag: the jaboticaba pomace. A comparison of physicochemical, technological and morphological properties of the jaboticaba powders obtained from the pomace, from the whole fruit and from the peel was performed. All the powder samples underwent the same processing: freeze-drying, milling and sieving. The powders appeared reddish, with an average diameter of approximately 64.83–103.51 μm and pH values of 3.45–3.74, water activity of 0.3133–0.3270, water holding capacity of 2.63–4.28 g H2O/g and oil holding capacity of 2.79–2.98 g oil/g. Differential scanning calorimetry analysis showed that the endothermic peak temperature was 158.9–164.4 °C. Proximate composition analysis showed a large amount of total dietary fibre and insoluble dietary fibre in jaboticaba pomace (20.54 and 16.42 g/100 g, respectively), while jaboticaba peel had a good amount of soluble dietary fibre (10.72 g/100 g). Jaboticaba pomace had a large quantity of phenolic compounds (43.39 mg GAE/g d.w.), especially monomeric anthocyanin (3.92 mg cyanidin-3-glucoside/g d.w.), compared to the whole fruit. Jaboticaba pomace is valuable due to its high phenolic content (2.5 times higher than the whole fruit) and total dietary fibre content (2.2 times higher than the whole fruit). The results obtained in this study reinforce the idea that this co-product could be re-used in the development of functional ingredients and show that the industrialisation of these materials is one possible alternative for food diversification. Pomace powder could be added to many types of foods, such as cereals, snacks, drink mixes, and breads, or could be used for pharmaceuticals, such as slow-release antioxidants in packaging films.
    Food Research International 08/2014; 62:786-792. DOI:10.1016/j.foodres.2014.04.042 · 3.05 Impact Factor