Influence of barley variety and growing locality on the profile of flavonoid polyphenols in malt

Some polyphenol substances are important for beer production as well as for the health benefits of beer consumption. Hop polyphenols have been relatively well researched in the last decade, less attention has been paid to malt. Our study was aimed to determine the influence of the barley variety and growing locality on the profile of proanthocyanidins (PAC), monomeric flavanols, flavonols and their glycosides in malt. Laboratory malts from three barley cultivars grown in seven countries of the European Union were analyzed by the developed LC-HR / MS method with sample preparation by the QuEChERS technique. Dimers of (epi)catechin (37.0%) and dimers (epi)catechin – (epi) gallocatechin (36.4%) dominate the PAC profile of malt, monomer content being low. Flavanols (epi)catechin and (epi)catechin-O-glucoside have been identified and quantified in malts. The flavonols were quercetin and myricetin, their glycosides were not detected. The results suggest varietal dependence of the PAC, monomeric flavanols and flavonols profile and the lesser impact of the growing locality.

Lack of acute or chronic effects of epicatechin-rich and procyanidin-rich apple extracts on blood pressure and cardiometabolic biomarkers in adults with moderately elevated blood pressure: a randomized, placebo-controlled crossover trial

ABSTRACT Background The reported effects of flavanol-rich foods such as cocoa, dark chocolate, and apples on blood pressure and endothelial function may be due to the monomeric flavanols [mainly (–)-epicatechin (EC)], the oligomeric flavanols [procyanidins (PCs)], or other components. Reports of well-controlled intervention studies that test the effects of isolated oligomeric flavanols on biomarkers of cardiovascular health are lacking. Objective We studied the acute and chronic effects of an EC-rich apple flavanol extract and isolated apple PCs on systolic blood pressure (BP) and other cardiometabolic biomarkers. Design Forty-two healthy men and women with moderately elevated BP completed this randomized, double-blind, placebo-controlled, 4-arm crossover trial. Participants ingested a single dose of an apple flavanol extract (70 mg monomeric flavanols, 65 mg PCs), a double dose of this extract (140 mg monomeric flavanols, 130 mg PCs), an apple PC extract (130 mg PCs, 6.5 mg monomeric flavanols), or placebo capsules once daily for 4 wk, in random order. Biomarkers of cardiovascular disease risk and vascular function were measured before and 2 h after ingestion of the first dose and after the 4-wk intervention. Results Compared with placebo, none of the isolated flavanol treatments significantly (P < 0.05) changed systolic or diastolic BP (peripheral and aortic), plasma nitric oxide (NO) reaction products, or measures of arterial stiffness (carotid femoral pulse-wave velocity, brachial-ankle pulse-wave velocity, or Augmentation Index) after 2 h or 4 wk of the intervention. There were no changes in plasma endogenous metabolite profiles or circulating NO; endothelin 1; total, HDL, or LDL cholesterol; triglycerides; fasting glucose; fructosamine; or insulin after 4 wk of the intervention. Conclusions Our data suggest that, in isolation, neither monomeric flavanols nor PCs affect BP, blood lipid profiles, endothelial function, or glucose control in individuals with moderately elevated BP. The reported benefits of consuming flavanol-rich cocoa, chocolate, and apple products appear to be dependent on other components, which may work in combination with monomeric flavanols and PCs. This trial was registered at www.clinicaltrials.gov as NCT02013856.

Effect of the harvest season on phenolic composition and oenological parameters of grapes and wines cv. ‘Touriga Nacional’ (Vitis vinifera L.) produced under tropical semi-arid climate, in the state of Pernambuco, Brazil

The northeastern region of São Francisco Valley is the third largest wine producer in Brazil, differentiated by the production of at least two harvests per year, generally in the first and second semesters, respectively. The productive cycle of the vine in the first semester is higher than in the second semester, mainly due to differences in temperature, with maximum and average temperatures of approximately 30 ºC and 26 ºC, respectively. Second semester is characterized by higher temperatures (summer season) and that promote a rapid maturation of the grapes. The objective of this work was to evaluate the phenolic composition, other oenological parameters and the sensorial profile of grapes and wines of cv. 'Touriga Nacional' (Vitis vinifera L.), characterizing grapes and wines from four harvest seasons, two of them referring to the first half of the year and two referring to the second half of the year, using a broad analytical approach. The experimental design consisted of three randomized blocks, with sixty plants marked in different lines and positions (twenty plants in each block at the beginning, middle and end of the vineyard). The results showed that there was a harvesting effect for some of the grape chemical compounds (monomeric anthocyanins, organic acids, condensed tannins and monomeric flavanols, for example) as well as in wines (calcium, monomeric anthocyanins, condensed tannins and monomeric flavanols). Regarding the sensorial profile of the wines, it was possible to observe that higher scores were attributed to floral aroma in wines from the first harvest (first half of the year). Fruity, spice and empyreumatic aromas were higher in wines from second harvest season (second half of the year). For other attributes, there was a tendency for higher variations between the period of study (2014 – 2017) than between the harvest seasons.

Method for the Determination of Catechin and Epicatechin Enantiomers in Cocoa-Based Ingredients and Products by High-Performance Liquid Chromatography: Single-Laboratory Validation

A single-laboratory validation study was performed for an HPLC method to identify and quantify the flavanol enantiomers (+)- and (–)-epicatechin and (+)- and (–)-catechin in cocoa-based ingredients and products. These compounds were eluted isocratically with an ammonium acetate–methanol mobile phase applied to a modified β-cyclodextrin chiral stationary phase and detected using fluorescence. Spike recovery experiments using appropriate matrix blanks, along with cocoa extract, cocoa powder, and dark chocolate, were used to evaluate accuracy, repeatability, specificity, LOD, LOQ, and linearity of the method as performed by a single analyst on multiple days. In all samples analyzed, (–)-epicatechin was the predominant flavanol and represented 68–91% of the total monomeric flavanols detected. For the cocoa-based products, within-day (intraday) precision for (–)-epicatechin was between 1.46–3.22%, for (+)-catechin between 3.66–6.90%, and for (–)-catechin between 1.69–6.89%; (+)-epicatechin was not detected in these samples. Recoveries for the three sample types investigated ranged from 82.2 to 102.1% at the 50% spiking level, 83.7 to 102.0% at the 100% spiking level, and 80.4 to 101.1% at the 200% spiking level. Based on performance results, this method may be suitable for routine laboratory use in analysis of cocoa-based ingredients and products.