Sweet peppers (Capsicum annuum L.) cv. Vergasa have been studied at four maturity stages (immature green, green, immature red, and red). The individual phenolics (hydroxycinnamic acids and flavonoids), vitamin C (ascorbic acid and dehydroascorbic acid), and individual carotenoids were characterized and quantified. Five hydroxycinnamic derivatives and 23 flavonoids were characterized and quantified from the pericarp of sweet pepper by high-performance liquid chromatography-diode array detection-electrospray ionization-mass spectrometry. Identification was carried out by their UV spectra, chromatographic comparisons with authentic markers, identification of hydrolysis products, and tandem mass spectrometry analysis. Hydroxycinnamic derivatives, O-glycosides of quercetin, luteolin, and chrysoeriol, and a large number of C-glycosyl flavones have been characterized. Some of these compounds were found for the first time in nature. Clear differences in the individual and total phenolic content were detected between the different maturity stages. Immature green pepper had a very high phenolic content while green, immature red, and red ripe peppers showed a 4-5-fold reduction. Ascorbic acid was the main form of vitamin C, and its content increased as the pepper reached maturity. The red ripe stage had a relevant impact on the carotenoids content. Thus, immature green peppers showed the highest content of polyphenols, while red ripe fruits had the highest content of vitamin C and provitamin A.

Cocoa is a food rich in polyphenols, mainly the flavonoid procyanidins and flavan-3-ols. The improvement of the cardiovascular function in humans upon cocoa consumption has been specifically linked to the presence of flavan-3-ol derived metabolites in plasma, especially epicatechin glucuronide. In this context, a flavonoid-enriched cocoa-derived product could potentially exert stronger health benefits. The aim of the present study was to obtain a cocoa powder with a higher flavonoid content (mainly enriched in monomer compounds) and assess its flavonoid bioavailability in humans. For this purpose, an unfermented, nonroasted, and blanch-treated cocoa powder (A) was obtained. The powder contained four times more procyanidins than a conventional (B) cocoa powder. Powder A contained eight times more epicatechin and procyanidin B2 than powder B. Cocoa milk drinks were prepared with powder A (MDA) and B (MDB). The bioavailability of flavonoids in both drinks was assessed in a crossover intervention with healthy volunteers. The content of epicatechin glucuronide, the main metabolite detected in plasma, was five-fold higher upon consumption of MDA as compared with MDB. The urinary excretion of metabolites, mainly methyl epicatechin sulfate, was higher upon MDA consumption as compared with MDB, ranging from two-to 12-fold higher depending on the metabolite. These results, together with previous reports regarding the cardiovascular benefits linked to the presence of procyanidin metabolites in plasma, suggest that further clinical trials to validate the health benefits of a flavonoid-enriched cocoa powder are warranted.

The use of ozonated water as a sanitizer to extend the shelf life of fresh-cut lettuce and the effect on the antioxidant constituents (polyphenols and vitamin C) were investigated. Fresh-cut iceberg lettuce (Lactuca sativa L.) was washed at 4 degrees C using three different ozonated water dips [10, 20, and 10 activated by ultraviolet C (UV-C) light mg L(-1) min total ozone dose], and the dips were compared with water and chlorine rinses. Treated lettuce was packaged in air or active modified atmosphere packaging (MAP) (4 kPa of O2 + 12 kPa of CO2 balanced with N2) and stored for 13 days at 4 degrees C. Despite its strong oxidizing activity, ozonated water did not stimulate the respiratory activity of fresh-cut lettuce. Moreover, ozonated water maintained the initial visual appearance of fresh-cut lettuce and controlled browning during storage in air. Initially, ozonated water and chlorine reduced the total mesophilic population by 1.6 and 2.1 log, respectively, when compared with water. Active MAP was effective in controlling total microbial growth, achieving 2.0 log reduction in relation to samples stored in air at the end of storage. On the other hand, active MAP caused a 2.0-3.5 reduction of coliforms on sanitized samples compared with water-washed samples. The most efficient treatments were ozone 20 and ozone 10 activated by UV-C, which were as effective as chlorine. Changes in individual phenolic compounds were independent of the washing treatments. In air, chlorogenic and isochlorogenic acid contents increased noticeably after 13 days while monocaffeoyltartaric and dicaffeoyltartaric acids remained unchanged. MAP effectively suppressed accumulation of caffeoylquinic derivatives, whereas caffeoyltartaric derivatives decreased during MAP storage to reach similar levels. The content of vitamin C (ascorbic acid and dehydroascorbic acid) decreased during storage, particularly under MAP. Ozonated water could be an alternative sanitizer to chlorine for fresh-cut lettuce due to good retention of sensorial quality and browning control with no detrimental reduction in the antioxidant constituents.

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The lack of consistency in homogeneous color throughout the season of pigmented baby leaf lettuce is a problem for growers because of the rejection of the product and consequently the economic loss. Changes in color as well as individual and total phenolic composition and content as a response to the climatic variables were studied following the analysis of three pigmented baby leaf lettuces over 16 consecutive weeks from February to May, which corresponded to the most important production season in winter in Europe. Color and phenolic content were significantly (P ≤ 0.001) affected by cultivar, harvest week, and climatic variables that occurred in the last week before harvest. Radiation and temperature showed positive correlations with the content of phenolic acids and flavonoids that increased in all three cultivars as the season progressed. Cyanidin-3-O-(6''-O-malonyl)-glucoside content showed positive correlations with temperature and radiation but only in Batavia cultivars whereas in red oak leaf the correlation was with cold temperatures. Regarding hue angle, a positive correlation was shown with the number of hours at temperatures lower than 7 °C. A relationship between hue angle and the content of anthocyanins was not possible to establish. These results suggest that the colorimetric measurement of color cannot be used as a good indicator of anthocyanin accumulation because other pigments such as chlorophylls and carotenoids may contribute as well to the leaf color of pigmented lettuce. This study provides information about the impact of genotype and environment interactions on the biosynthesis of phenolic compounds to explain the variability in the leaf color and product appearance.