Alkalization is an important process in cocoa powder production that affects color and flavor. In this study, the impact of alkalization temperature (60, 70, 80, 90, 100 °C), NaOH concentration ...(0.59, 1.17, 2.34, 3.59% w/w of cocoa powder) and alkalization time (1 and 10 min) on the physicochemical properties (pH, color) and phytochemical profile (theobromine, caffeine, epicatechin, catechin) of cocoa powder were investigated, while the aroma was studied on the corresponding cocoa drinks. High-performance liquid chromatography coupled to an ultra-violet detector (HPLC-UV) was used for screening the non-volatiles and headspace solid - phase microextraction - gas chromatography - mass spectrometry (HS-SPME-GC-MS) for the aromatic compounds. Major changes of the cocoa properties occurred during the first minute of alkalization. Increase of temperature and alkali concentration generally reduced the levels of epicatechin and the lightness (L*), while the pH of the cocoa powder was affected by changing the alkali concentration. On the other hand, the reddish (a*) and yellowish (b*) color component values and theobromine levels were not significantly affected by varying temperature and alkali concentration. A higher temperature did not affect the concentration of the volatile compounds, while a decrease in certain chemical classes was observed by increasing the alkali concentration.
•Cocoa powder alkalization is a rapid reaction but difficult to be controlled.•Most changes on pH, color and caffeine occur during the first min of alkalization.•High alkali concentrations have a negative effect on phytochemical content.•Volatiles change mainly when varying the alkali concentration than temperature.•Harsher temperatures or alkalization prior roasting could affect the volatiles.
Background: Prospective cohort studies have shown that the consumption of cocoa and tea is associated with lower risk of cardiovascular diseases (CVDs), and cocoa and tea have been shown to improve ...CVD risk factors in randomized controlled trials. Cocoa and tea are major dietary sources of the flavan-3-ol epicatechin.
Objective: We investigated the associations of dietary epicatechin intake with 25-y CVD mortality in elderly Dutch men.
Design: We used data from the Zutphen Elderly Study, which was a prospective cohort study of 774 men aged 65–84 y in 1985. Epicatechin intake was estimated 4 times in 15 y with the use of the crosscheck dietary history method. Time-dependent Cox proportional hazards models were used to investigate repeated measures of epicatechin intake in relation to 25-y CVD mortality.
Results: Mean intake of epicatechin was 15.2 ± 7.7 mg/d, and the major dietary sources were tea (51%), apples (28%), and cocoa (7%). During 25 y of follow-up, 329 men died from CVD, 148 died from coronary heart disease (CHD), and 72 men died from stroke. Risk of CHD mortality was 38% lower in men in the top tertile of epicatechin intake than in men in the bottom tertile of epicatechin intake (HR: 0.62; 95% CI: 0.39, 0.98). Epicatechin intake was also significantly associated with 46% lower risk of CVD mortality in men with prevalent CVD (HR: 0.54; 95% CI: 0.31, 0.96) but not in men who were free of CVD.
Conclusions: We show, for the first time to our knowledge, that epicatechin intake is inversely related to CHD mortality in elderly men and to CVD mortality in prevalent cases of CVD. More studies are needed before conclusions can be drawn.
• Poplar trees synthesize flavan-3-ols (catechin and proanthocyanidins) as a defense against foliar rust fungi, but the regulation of this defense response is poorly understood. Here, we investigated ...the role of hormones in regulating flavan-3-ol accumulation in poplar during rust infection.
• We profiled levels of defense hormones, signaling genes, and flavan-3-ol metabolites in black poplar leaves at different stages of rust infection. Hormone levels were manipulated by external sprays, genetic engineering, and drought to reveal their role in rust fungal defenses.
• Levels of salicylic acid (SA), jasmonic acid, and abscisic acid increased in rust-infected leaves and activated downstream signaling, with SA levels correlating closely with those of flavan-3-ols. Pretreatment with the SA analog benzothiadiazole increased flavan-3-ol accumulation by activating the MYB–bHLH–WD40 complex and reduced rust proliferation. Furthermore, transgenic poplar lines overproducing SA exhibited higher amounts of flavan-3-ols constitutively via the same transcriptional activation mechanism. These findings suggest a strong association among SA, flavan-3-ol biosynthesis, and rust resistance in poplars. Abscisic acid also promoted poplar defense against rust infection, but likely through stomatal immunity independent of flavan-3-ols. Jasmonic acid did not confer any apparent defense responses to the fungal pathogen.
• We conclude that SA activates flavan-3-ol biosynthesis in poplar against rust infection.
Astringency is a highly complex sensation which involves multiple mechanisms occurring simultaneously, such as the interaction between flavan-3-ols and salivary proteins (SP). Moreover, astringency ...development can be affected by the presence of polysaccharides such as mannoproteins (MP). The aim of this work was to evaluate the molecular mechanisms whereby MP could modulate the astringency elicited by tannins, using a cell-based model of the oral epithelium (TR146 cells), and the effect of salivary proteins on these interactions. The binding of flavan-3-ols to oral cells was evaluated by DMACA assay, while the content of unbound flavan-3-ols after the interactions was assessed by means of HPLC-DAD-MS. Results obtained confirm the existence of cell–tannin interactions, that can be partially inhibited by the presence of SP and/or MP. The most significant decrease was obtained in the system containing MPF (38.16%). Both mannoproteins assayed seem to have modulating effect on flavan-3-ol–SP interactions, acting by two different mechanisms: MPF would lead to the formation of SP/MPF/flavan-3-ols ternary soluble aggregates, while MPL seems to prevent flavan-3-ol–saliva interaction by a competitive mechanism, i.e., MPL would reduce cell–tannin interactions, similar to SP. This study suggests that mannoproteins with different compositional characteristics could exhibit preferential interaction with distinct flavan-3-ol families.
•Barley is an important dietary source of β-glucan, tocols and (poly)phenols.•A total of 64 (poly)phenolic compounds were identified in barley samples.7•One flavone glucoside and 3 anthocyanins are ...described for the first time in barley.•The geographic origin of barley genotypes determines the content of some minortocols.•Contents of some phenolics were influenced by grain colour and hull.
In the present study, 27 barley genotypes (Hordeum vulgare L.) grown in two geographic origins (Czech Republic and Spain) were analysed for their contents of β-glucan, tocols and phenolic compounds (free and bound). The samples included hulled, hull-less and coloured genotypes. The results showed that concentrations of β-glucan range from 2.40 to 7.42g/100g. Total tocol content of the barley samples ranged between 39.9 and 81.6μg/g. A total of 64 compounds were identified in the barley samples. These included 19 phenolic acids and aldehydes, 9 flavan 3-ols, 9 flavone glycosides, and 27 anthocyanins. The results showed a wide range of phenolic concentrations in the barley samples, highlighting the presence of considerable amounts of anthocyanins in purple barley genotypes. In synthesis, barley should be considered a good source of bioactive components, especially because of the broad spectrum of phytochemicals with potential health benefits besides the soluble fibre (β-glucan).
Tea, as one of the most popular beverages with various bioactivities, is commonly produced from the fresh leaves of two widely cultivated tea plants, Camellia sinensis and C. sinensis var. assamica. ...Both plants belong to the genus Camellia section Thea, which was considered to have 12 species and 6 varieties according to Min’s taxonomic system. Most species, except the cultivated species, are known as wild tea plants and have been exploited and utilized to produce tea by the local people of its growing areas. Thus far, six species and varieties have been phytochemically studied, leading to the identification of 398 compounds, including hydrolyzable tannins, flavan-3-ols, flavonoids, terpenoids, alkaloids, and other phenolic and related compounds. Various beneficial health effects were reported for tea and its components, involving antioxidant, antitumor, antimutagenic, antidiabetic, hypolipidemic, anti-inflammatory, antimicrobial, antiviral, antifungal, neuroprotective, hepatoprotective, etc. In this review, the geographical distribution of tea plants and the chemical constituents (1–398) reported from the genus Camellia section Thea and some tea products (green, black, oolong, and pu-erh tea) that have ever been studied between 1970 and 2018 have been summarized, taking species as the main hint, and the main biological activities are also discussed.
Avocado is a tropical fruit increasingly cultivated around the world due to global interest and rising consumption. Thus, there is also a surge in avocado by-products that needs assessment. The aim ...of this work is to compare the phenolic profile of avocado pulp, peel and seed when the fruit is at optimal ripeness for consumption and when overripe. Two analytical techniques were used: (1) HPLC-DAD-ESI-QTOF-MS was used for the first time to determine phenolic and other polar compounds in avocado peel and seed. Phenolic compounds quantified with these methods were in higher concentration in overripe than in pulp and seed of optimally ripe fruit. (2) HPLC-FLD-MS was used to specifically determine flavan-3-ols. Procyanidins to degree of polymerization 13 have been quantified singularly here for the first time. In addition, A- and B-type procyanidins from the degree of polymerization 2 to 6 were differentiated and quantified. The procyanidin concentration increased after ripening probably due to the release of tannins linked to cell-wall structures. Because of this situation and the presence of A-type procyanidins, avocado peel and seed from overripe fruit, the main by-products of avocado processing, hold interest for developing functional foods, nutraceuticals and cosmetics.
•Phenolic compounds of avocado peel and seed were determined by HPLC-DAD-ESI-qTOF-MS for the first time.•Phenolic compounds were more concentrated in over-ripped than in optimal avocado pulp and seed.•Procyanidins until degree of polymerization 13 have been quantified singularly for the first time.•A and B-type procyanidins from degree of polymerization 2 to 6 could be differed and quantified.
Jambolan fruit has been used in traditional Indian medicine and has recently attracted interest as a functional food. The comprehensive study by HPLC–DAD-ESI-MS/MS has revealed the occurrence of ...around 74 individual phenolic compounds in the edible parts of jambolan, including 9 anthocyanins (mainly based on delphinidin, petunidin and malvidin), 9 flavonols (myricetin, laricitrin and syringetin glycosides), 19 flavanonols (dihexosides of dihydromyricetin and its methylated derivatives), 8 flavan-3-ol monomers (mainly gallocatechin), 13 gallotanins and 13 ellagitanins, together with some proanthocyanidins (highly galloylated prodelphinidins) and free gallic and ellagic acids. No hydroxycinnamic acid derivatives were detected. The skin of the jambolan fruit accumulated great amounts of phenolic compounds, almost all of the non-tannin phenolics. In contrast, condensed tannins (proanthocyanidins) and hydrolyzable tannins (gallotannins and ellagitannins) were present in both edible parts, accounting for greater amounts in the skin. Overall, the main phenolics of jambolan were anthocyanins and hydrolyzable tannins (similar amounts of gallotannins and ellagitanins), followed by flavanonols, flavonols and flavan-3-ols.
•74 individual phenolics found in the edible parts of jambolan, mainly in the skin•Anthocyanins, gallotannins and ellagitannins are the main phenolics.•High amounts of flavanonols are also found in jambolan.•Jambolan flavonols derived from myricetin, laricitrin and syringetin•Condensed tannins are minor phenolics and hydroxycinnamates were not found.
•Effect of different dying methods on key quality parameters of dried jujube fruits.•Bioactive compounds, antioxidant capacity, and sensory attributes form quality.•The best quality of the dried ...product was found in fruits treated by FD and VMD 480–120W.
The aim of this study was to determine the effect of different dying methods, such as convective drying (CD: 50, 60, 70°C), vacuum-microwave drying (VMD: 120, 480, 480–120W), a combination of convective pre-drying and vacuum-microwave finish drying (CPD (60°C)-VMFD (480–120W), and freeze-drying (FD) on key quality parameters of dried jujube fruits (cv. “GAL”, “MSI”, and “PSI”). The parameters studied included bioactive compounds (flavan-3-ols and flavonols, identified by LC-PDA-MS, and vitamin C), antioxidant capacity (ABTS and FRAP), and sensory attributes (e.g. hardness, jujube-ID, and sweetness). The best quality of the dried product (high contents of bioactive compounds and high intensity of key sensory attributes) was found in fruits treated by FD and VMD 480–120W. The best cultivars were “PSI” and “GAL” from the point of view of bioactive content and sensory quality, respectively.
► Phenolic compounds in strawberry were identified and quantified by HPLC-DAD-MSn. ► The phenolic composition in fruits of 27 strawberry cultivars were determined. ► The concentration of all phenolic ...compounds were affected by cultivar. ► Levels of anthocyanins and cinnamic acid derivatives were most affected by ripening. ► The anthocyanin profiles were nearly unaffected by ripening and growing conditions.
Phenolic compounds in fruits of 27 cultivars of strawberry (Fragaria x ananassa Duch.) grown in Norway were characterised and quantified by HPLC-DAD-MSn. Total phenolic content, calculated as the sum of the individual compounds, varied 2.3-fold among cultivars, i.e., from 57 to 133mg/100g of fw. There were significant differences among cultivars in concentration of all phenolic compounds. The highest variation between cultivars was found for cinnamoyl glucose (0.6–24.9mg/100g of fw). Concentration of anthocyanins, the most abundant class of phenolic compounds in the majority of the cultivars, varied from 8.5 to 65.9mg/100g of fw. Flavan-3-ols (11–45mg/100g of fw) and ellagitannins (7.7–18.2mg/100g of fw) contributed on average 28% and 14% to total phenolic contents in the strawberry cultivars, respectively. In three cultivars harvested at three stages of ripeness, anthocyanins and cinnamic acid conjugates were the compounds most affected by ripening. The anthocyanin profile for the individual cultivars was only slightly affected by ripening and growing conditions.
PDF
