Flavonol Content Research Articles

Phytochemical constituent and oxidative potencies of acetone, methanol and aqueous leaf extracts of Acalypha Wilkesiana grown at the Kaura Namoda plant nursery

As a result of increased interest in the production of plant-based drugs for the treatment of many diseases has become a significant reason why people have become more coversant in the use of traditional medicine for the treatment of mild and serious illness. Due to increase in the thrust for the production of plant-based drugs, this present study was carried out to compare the phytochemical constituents and antioxidant potencies of acetone, methanol and aqueous leaf extracts of Acalypha wilkesiana collected from Kaura Namoda Botanical Garden in Zamfara State-Nigeria. The antioxidant activities was evaluated using various assays; The total phenolic content of aqueous, methanol and acetone leaf extract were 15.58 0.66 mg GAE/g, 14.10 2.17 mg GAE/g and 8.70 0.01 mg GAE/g respectively. Total flavonol contents; 207.10 11.53 mg QE/g, 196.08 5.53 mg QE/g and 112.04 8.27 mg QE/g respectively. Total flavonoid contents; 240.99 9.50 mg QE/g, 252.52 3.73 mg QE/g and 123.88 5.58 mg QE/g respectively. FRAP values were 679.14 0.45 mmol/g, 611.90 7.09 mmol/g and 292.07 11.38mmol/g respectively. ABTS activity of aqueous, methanol and acetone leaf extract were 24.30 5.86 mg AAE/g, 14.49 1.02 mg AAE/g and 7.00 0.57 mg AAE/g respectively, methanol leaf extract had the highest percentage DPPH Inhibition value of 42.64 5.13, followed by aqueous (31.77 4.08) at 0.25mg/ml while aqueous had the highest (52.63 0.67), followed by methanol extract (44.80 2.80) at 0.50mg/ml. Aqueous extract had the highest percentage inhibition of Nitric Oxide with a value of 59.74 1.30, followed by methanol extract (46.11 2.54) at 0.25mg/ml. inhibition for aqueous was also highest at 0.5 mg/ml. Aqueous extract had the highest percentage lipid peroxidation inhibition value of 22.66 2.93, followed by methanol leaf extract with the value of 18.89 0.80 while at 0.50mg/ml methanol leaf extract had the highest percentage inhibition of lipid peroxidation (39.42 3.10), followed by aqueous leaf extract with the value of 31.48 1.61. The results showed that aqueous and methanol leaf extract of Acalypha wilkesiana displayed potent antioxidant effects with the aqueous having an edge. This present study therefore supports the view that Acalypha wilkesiana can be used in the management of oxidative stress and other related diseases.

The impact of sustainable management regimes on amino acid profiles in grape juice, grape skin flavonoids and hydroxycinnamic acids

Organic and biodynamic management practices in viticulture have been sharply increasing worldwide for almost two decades and are seen as one possibility for environmentally friendly production. Consumers often presume that the quality of organically grown crops is different or higher compared to conventionally grown crops.In the current study, wine grape quality under integrated, organic and biodynamic viticulture was assessed in a long-term field trial in Geisenheim, Germany, starting seven years after conversion. Treatments substantially differed in their amino acid concentration in juice, flavonol content and their composition of hydroxycinnamic acids. Organic and biodynamic treatments showed significantly higher concentrations of all amino acids in juice and a significantly higher concentration of flavonols in berry skins. Major drivers of these changes are reductions of yield and pruning weight under organic and biodynamic management on the one hand and increased light exposure of bunches in the respective treatments on the other hand.Linking amino acid composition in juice, grape skin flavonoid and hydroxycinnamate concentration to canopy structure, vigour and yield enables growers to actively control and manipulate wine grape quality in the different management systems.

Key genes for phenylpropanoid metabolite biosynthesis during half-highbush blueberry (Vaccinium angustifolium×Vaccinium corymbosum) fruit development

BACKGROUND: Blueberry fruits contain large amounts of phenolic compounds derived from the phenylpropanoid pathway. Their biosynthesis is complex, involving many enzymes. OBJECTIVE: We sought to investigate the content of phenylpropanoid-derived compounds and identify key genes involved in the phenylpropanoid metabolite pathway during half-highbush blueberry fruit development. METHODS: Phenylpropanoid metabolite contents were determined by high-performance liquid chromatography (HPLC) and spectrophotometry. Gene expression was examined through reverse-transcription PCR. RESULTS: Phloretin, chlorogenic acid, total flavonol, quercetin, catechin, and proanthocyanidin contents were highest in small-sized green fruits; myricetin and epicatechin contents were highest in pink fruits; and lignin and anthocyanin were highest in blue fruits. Genes from the 4-coumarate CoA ligase (4CL) family regulate the biosynthesis of phenylpropanoid metabolites. Phenylalanine ammonia-lyase (PAL) and cinnamoyl-CoA reductase (CCR) are key genes in the lignin biosynthetic pathway. Flavonol synthase (FLS) is a key gene affecting total flavonols and the quercetin biosynthetic pathway. PAL and chalcone isomerase (CHI) are key genes in the epicatechin and anthocyanin biosynthetic pathways, respectively. CONCLUSION: Phenylpropanoid metabolites are regulated by multiple genes from the same or different families. Enzymes in different metabolic pathways compete for precursors to form a complex regulatory network for phenylalanine metabolism.

Photoselective Shade Films Mitigate Heat Wave Damage by Reducing Anthocyanin and Flavonol Degradation in Grapevine (Vitis vinifera L.) Berries

Wine grape production is challenged by forecasted increases in air temperature and droughts due to climate change and photoselective overhead shade films are promising tools in hot viticulture areas to overcome climate change related factors. The aim of this study was to evaluate the vulnerability of ‘Cabernet Sauvignon’ grape berries to solar radiation overexposure, optimize shade film use for preserving berry composition. An experiment was conducted for two years with four shade films (D1, D3, D4, D5) with differing solar radiation spectra transmittance and compared to an uncovered control (C0). Integrals for leaf gas exchange and mid-day stem water potential were unaffected by the shade films in both years. At harvest, berry primary metabolites were not affected by treatments applied in either year. Despite precipitation exclusion during the dormant seasons in shaded treatments, and cluster zone temperatures reaching 58°C in C0, yield was not affected. Berry skin anthocyanin and flavonol composition and content were measured by C18 reversed-phase HPLC. In 2020, total skin anthocyanins (mg·berry-1) in the shaded treatments were 27% greater than C0 during berry ripening and at harvest. Conversely, flavonol content in 2020 decreased in partially shaded grapevines compared to C0. Berry flavonoid content in 2021 increased until harvest while flavonol degradation was apparent from veraison to harvest in 2020 across partially shaded and control grapevines. Untreated control showed lower di- to tri-hydroxylated flavonol ratios closer to harvest. Our results provided evidence that overhead partial shading of vineyards mitigate anthocyanin degradation by reducing cluster zone temperatures and is a useful tool in combatting climate change in hot climate regions.

Effect of Covering Crops between Rows on the Vineyard Microclimate, Berry Composition and Wine Sensory Attributes of ‘Cabernet Sauvignon’ (Vitis vinifera L. cv.) Grapes in a Semi-Arid Climate of Northwest China

Covering crops was a commonly used viticultural technique to adjust the vineyard microclimate, thus affecting the grape and wine quality. In this two-year study, the purslane (Portulaca oleracea L.) was used to cover the lands between rows in the vineyards located in the semi-arid Northwest China, Xinjiang. Results showed that the photosynthetically active radiation around the fruit zone and the temperature with the purslane covering treatment decreased. Compared with the clean tillage, covering purslane had lower TSS and higher TA in the grape berries, while lower alcohol content and higher TA was also found in their corresponding wines. Covering purslane treatment significantly increased the contents of anthocyanin and flavonol in the grapes and wines in the year 2018, but no significant effect on flavanols was observed in the wines. Norisoprenoids, esters, and C6 alcohols in the grapes and wines were increased in the purslane covering treatment, respectively. Additionally, compared to the clean tillage, the purslane covering treatment significantly improved the sensory value of the wines, especially the floral aroma and the complexity of the wines. This study helped us to better understand the feasibility of applying covering purslane in viticulture in the semi-arid climate of Northwest China.

Non-Volatile and Volatile Bioactives of Salvia officinalis L., Thymus serpyllum L. and Laurus nobilis L. Extracts with Potential Use in the Development of Functional Beverages.

Functional beverages based on herbal extracts are highly demanded products due to the presence of bioactives with promising health benefits and interesting and characteristic sensory properties. Mediterranean medicinal and aromatic herbs contain a wide range of bioactives (non-volatile polyphenols, volatile terpenes) that are important constituents of herbal extracts and essential oils. The antioxidant capacity and potential health benefits of these bioactives could be associated with their synergistic effects. Therefore, this study aimed to characterize the non-volatile and volatile bioactives of sage (Salvia officinalis L.), wild thyme (Thymus serpyllum L.) and laurel (Laurus nobilis L.) aqueous extracts and their two- and three-component mixtures as well as their antioxidant capacity. The content of total phenols, flavonoids, hydroxycinnamic acids and flavonols was determined spectrophotometrically. Individual polyphenols were analyzed by LC-MS/MS, the volatiles were analyzed by HS-SPME/GC-MS, and the antioxidant capacity was analyzed by ORAC and DPPH assays. The results showed that aqueous extracts of all examined herbs and their mixtures contained a high content of phenolic compounds ranging from 0.97 to 2.79 g L−1 of the sample, among which the most common were flavonols. At the same time, mono- and sesquiterpenes were the main volatiles. All extracts showed high antioxidant capacity, especially L. nobilis (781.62 ± 5.19 μmol TE mL−1 of the sample in the DPPH assay; 1896.10 ± 8.77 μmol TE mL−1 of the sample in the ORAC assay) and the two-component mixture of L. nobilis and T. serpyllum (679.12 ± 5.19 μmol TE mL−1 in the DPPH assay; 1913.38 ± 8.77 μmol TE mL−1 in the ORAC assay). Mixtures of herbal extracts have been shown to possess additive or synergistic effects, consequently contributing to higher antioxidant capacity. Therefore, two-component mixtures of herbal extracts showed promising potential for the production of functional beverages.

Effect of Flavonoid Dynamic Changes on Flower Coloration of Tulipa gesneiana ‘Queen of Night’ during Flower Development

Tulipa gesneriana has rich cultivars with abundant flower colors; among them, black tulips have become precious cultivars for their rareness in nature. It is of great significance to understand its color formation mechanism for breeding new cultivars with a blackish flower color in the future. In this present study, petals at five developmental stages of Tulipa gesneriana ‘Queen of Night’ (shorted for ‘QN’), a typical black tulip cultivar, were collected to identity the flavonoid composition and compare the accumulation along with the flower development process, aiming to explore the metabolic mechanism of its flower coloration. By using UPLC-Q-TOF-MS, three anthocyanins and nineteen anthoxanthins (including eighteen flavonols and one flavone) were detected in the petals of ‘QN’. The anthocyanins were identified as delphinidin 3-o-rutinoside, cyanidin 3-o-rutinoside and pelargonidin 3-o-rutinoside, respectively. The main flavonols were identified as quercetin, kaempferol, isorhamnetin, naringin and their glycosides. The only one flavone substance was identified as an apigenin derivative. By comparing the content, anthocyanins were the most abundant substance in the petals of ‘QN’, and showed obvious regularity in the development process. With the flower opening, the anthocyanin content accumulated continuously, and reached the highest level at 3575.9 μg·g−1·FW at S5, accounting for 80% of the total flavonoids. Among them, delphinidin 3-o-rutinoside and cyanidin 3-o-rutinoside made the main contribution to the coloration of ‘QN’. The content of anthoxanthins increased first and then decreased, reaching the highest to 1114.8 μg·g−1·FW at S3. Quercetin and its glycosides were the most important flavonol substances in the petals of ‘QN’, accounting for more than 60% of the total anthoxanthins in the five stages. The content of a flavone identified was extremely low, suggesting a limited role in the flower color of ‘QN’. Taken together, the flower color presentation of ‘QN’ was closely related to the composition and accumulation of anthocyanins and flavonols; anthocyanins were the main substances that determine the petal coloration of ‘QN’, and the high content of flavonols played a role of co-pigmentation with these anthocyanins.

Two homeologous MATE transporter genes, NtMATE21 and NtMATE22, are involved in the modulation of plant growth and flavonol transport in Nicotiana tabacum.

The multidrug and toxic compound extrusion (MATE) protein family has been implicated in the transport of a diverse range of molecules, including specialized metabolites. In tobacco (Nicotiana tabacum), only a limited number of MATE transporters have been functionally characterized, and no MATE transporter has been studied in the context of flavonoid transport in this plant species so far. In the present study, we characterize two homeologous tobacco MATE genes, NtMATE21 and NtMATE22, and demonstrate their role in flavonol transport and in plant growth and development. The expression of these two genes was reported to be up-regulated in trichomes as compared with the trichome-free leaf. The transcript levels of NtMATE21 and NtMATE22 were found to be higher in flavonol overproducing tobacco transgenic lines as compared with wild type tobacco. The two transporters were demonstrated to be localized to the plasma membrane. Genetic manipulation of NtMATE21 and NtMATE22 led to altered growth phenotypes and modulated flavonol contents in N. tabacum. The β-glucuronidase and green fluorescent protein fusion transgenic lines of promoter regions suggested that NtMATE21 and NtMATE22 are exclusively expressed in the trichome heads in the leaf tissue and petals. Moreover, in a transient transactivation assay, NtMYB12, a flavonol-specific MYB transcription factor, was found to transactivate the expression of NtMATE21 and NtMATE22 genes. Together, our results strongly suggest the involvement of NtMATE21 and NtMATE22 in flavonol transport as well as in the regulation of plant growth and development.

Changes in the Composition of Flavonols and Organic Acids during Ripening for Three cv. Sauvignon Blanc Clones Grown in a Cool-Climate Valley

The influence of the geographical location and clone type on the contents of flavonols and organic acids of Sauvignon blanc grapes over the ripening process was investigated. The assay was carried out on three commercial clones of cv. Sauvignon blanc (Clone 242, Clone 107, and Clone 1-Davis) grown in two zones (referred to as low and high zones) in Casablanca Valley, Chile. The low zone is closer to the Pacific Ocean (i.e., 20 km away) than the high zone (which is 37 km away). Clear differences in the contents of total phenols, flavonols and organic acids of the grapes were observed during ripening. All the clones grown in the low zone exhibited a higher titratable acidity than those grown in the high zone. An analysis of the flavonol contents of the grape skins showed differences among clones associated with the geographical zone of cultivation. There was no difference in the tartaric acid concentration among clone types; however, a higher tartaric acid concentration was found in clones grown in the low zone than those grown in the high zone for all clone types. Similar results were found for the malic acid concentration. A discriminant analysis showed that the chemical analysis for the contents of total phenols, flavonols and organic acids influenced the classification based on the clone type. The results showed that grapes of different qualities can be grown in two geographical subunits into the larger area of Casablanca Valley.

Antioxidant potential of various extracts from 5 common European mosses and its correlation with phenolic compounds

Summary Introduction: This paper presents the results of research about the antioxidant properties of extracts from 5 moss species, namely Brachythecium rutabulum, Callicladium haldanianum, Hypnum cupressiforme, Orthodicranum montanum and Polytrichastrum formosum. The macerates of each above mentioned species in water and ethanol (50% and 96%) solutions were analysed. Objective: Total phenolic acids, total flavonoids and total flavonols concentrations and content of carotenoids was determined. Also some phenolic compounds were determined by HPLC. Methods: The 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activities and the advanced oxidation protein products (AOPP) formation inhibition were studied. Results: The obtained results showed that the extracts prepared with 50% ethanol had the strongest radical scavenging activities. Every 50% ethanol extract also inhibited formation of AOPP. 96% ethanol extracts had the lowest free radical scavenging activities, although B. rutabulum extract strongly inhibited protein oxidation. Pearson’s correlation showed that the radical scavenging effects of water extracts and extracts prepared with 50% ethanol are dependent on the presence of phenolic acids and flavonoids. Conclusion: The results suggest the moss extracts as materials for potential use in pharmacy or cosmetology.

Study on South African Indigenous Teas-Antioxidant Potential, Nutritional Content, and Hypoxia-Induced Cyclooxygenase Inhibition on U87 MG Cell Line.

Background: This study comparatively assessed seven indigenous traditional tea plants on several attributes that included antioxidant, nutritional, caffeine contents, and cyclooxygenase activity. Methodology: Nutritional content of all tea plants were determined for energy, fat, carbohydrates, total sugars, dietary fiber and amino acids. Antioxidant potential and the antioxidant potentiating secondary metabolites were also measured and compared. Further, we investigated the tea plants for any role they would have on cyclooxygenase (COX) activity on cobalt chloride (CoCl2) induced human glioma cell lines (U87MG). Results: The tea plants were found non-cytotoxic at concentrations tested against the human Chang liver and HeK 293 kidney cells and were found to be naturally caffeine free. The lowest and highest extraction yield among the tea plants was 7.1% for B. saligna and 15.48% for L. scaberrimma respectively. On average, the flavonol content was 12 to 8 QE/g, ORAC 800 µmol TE/g, TEAC 150 µmol TE/g, FRAP 155 µmol AAE/g, polyphenols 40 mg GAE/g, flavanols 0.35 mg CE/g, flavonols 12 mg QE/g and total flavonoid content (TFC) 180 µg QE/mg. The COX activity has been found to be inhibited by a dose-dependent manner by L. scaberrimma, B. saligna and L. javanica. Conclusion: The results further support competitive value of tea plants and need for improved and further development.

Genetic and chemical diversity analyses in tale grapes (Vitis vinifera L.)

Vitis vinifera L. is one of the economically important plant crops worldwide which is a valuable food source for humans. This precious plant species has several local varieties and accessions which are continuously under selection and cultivation. Due to these human activities, the grape faces genetic homogeneity and erosion. Therefore, it is important to investigate available genetic diversity in grape plants all over the world. We aimed to study the genetic structure and diversity as well as chemical differences of seven grape cultivars in the country. We used SSR, and SRAP molecular markers for genetic diversity analyses, as well as biochemical traits. Both molecular markers showed a medium to moderate genetic variability in the studied grape cultivars (about 20% genetic polymorphism). Similarly, both molecular markers differentiated the studied cultivars into two genetic groups. AMOVA indicated significant genetic difference in these cultivars. ANOVA analysis of flavonols (quercetin, myricetin, kaempferol, and rutin) contents of seeds extract by HPLC indicated the significant difference (P <0.01) among grape cultivars. PCA biplot of cultivars based on chemical features separated these cultivars into two major groups according to their flavone and flavonoid contents. Pairwise Mantel tests performed between molecular and chemical data showed a significant association between SSR and SRAP data, but no significant association was obtained between either SSR or SRAP data with chemical features in grape cultivars studied. A heat-map constructed based on combined molecular and chemical data revealed that some of the studied grape cultivars are distinct in their genetic and chemical features.

PALYNOLOGICAL ANALYSIS, PHENOLIC COMPONENTS AND ANTI-INFLAMMATORY ACTIVITY OF SOME BEE POLLENS COLLECTED FROM THE NORTHEAST REGION OF ALGERIA

Bee pollen is multiplex blend of floral pollen and nectar agglutinated by bee salivary substances. It is famously known for being high in proteins, carbs, lipids, vitamins, and phenolic compounds, among other physiologically dynamic components. Its composition fluctuates incredibly agreeing to both botanical origins and edaphoclimatic conditions. In this work, the botanical origin, the phenolic components and the anti-inflammatory activity in vivo of eight bee pollens intended for human consumption were taken from distinctive apiaries in Algeria’s northeast, were determined and compared. All samples were detected heterofloral based on the identification of forty pollen types belonging to 22 botanical families. Total phenolic contents varied between 752.94 ± 17.78 and 12247.06 ± 40.04 mg GAE/ 100g, while the total flavonoid contents ranged from 2680.55 ± 12.02 to 8506.94 ± 15.56 mg QE/ 100g, and the total flavonol contents were in the interval between 4978.87 ± 33.39 and 7903.75 ± 24.39 mg QE/ 100g. The obtained results showed that the bulk of the ethanolic extracts had a good anti-inflammatory activity. As a conclusion, all the aforementioned heterofloral bee pollen samples could significantly be a wealthy source of polyphenols with a potential anti-inflammatory activity.

Genetic Diversity for Quercetin, Myricetin, Cyanidin, and Delphinidin Concentrations in 38 Blackeye Pea (Vigna unguiculata L. Walp.) Genotypes for Potential Use as a Functional Health Vegetable

Blackeye peas (Vigna unguiculata L. Walp.) are mainly used as a vegetable throughout the world, however they may contain significant concentrations of quercetin, myricetin, cyanidin, and delphinidin for potential use as a functional vegetable. Thirty-eight blackeye pea genotypes were selected from the core collection in the USDA, ARS, Plant Genetic Resources Conservation Unit’s cold storage at 4 °C during 2016. Information regarding concentrations of quercetin, myricetin, cyanidin, delphindin, and correlations among these as well as additional seed traits including seed coat color, seed pattern color, seed pattern, seed texture, and years in storage would add value to the blackeye pea genotypes for use as a functional vegetable. Using high performance liquid chromatography (HPLC), the red seeded accession originating from Mozambique, PI 367927 produced the highest quercetin (469.53 µg/g) and myricetin (212.23 µg/g) concentrations. The black seeded genotype, PI 353236, originating from India, produced the highest cyanidin (1,388.82 µg/g) concentration. However, PI 353236 and the brown seeded genotype, PI 353352 from India produced the highest concentrations of delphinidin (1,343.27 and 1,353.94 µg/g), respectively. Several correlations were observed and interestingly only delphinidin showed a significant negative correlation (r = −0.293*) with years in cold storage indicating that delphinidin declined in the seeds stored the longest (from 4-45 years) at 4 °C. Principal component analysis (PCA) explained how the flavonols, anthocyanidins, and the additional seed traits contributed to the variation of the blackeye pea genotypes. The cluster analysis showed six clusters representing low to high phytochemical concentrations. The genetic parameters including σ2g, σ2p, GCV, PCV, h2 h, and GG indicate that improvement in these phytochemical traits is possible through selection. The genotypic and phenotypic correlations showed that improving one phytochemical significantly improved the other except for cyanidin with delphinidin. These results can be used by scientists to develop blackeye pea cultivars with high flavonol and anthocyanidin concentrations.

Impact of Leaf Removal on Phenolics and Antioxidant Activity of Trebbiano Berries (Vitis vinifera L.).

Leaf removal is a canopy management practice widely applied in viticulture to enhance the phenol composition and concentration of grapes, which then results in improved wine quality. Many studies were carried out on red berried varieties, but information on white ones is scanty. The aim of the study was to assess the effect of basal leaf defoliation in post fruit set on the phenol composition, ascorbate level and antioxidant activity of Trebbiano grapes. Electron paramagnetic resonance was also employed to monitor the decay kinetics of 1,1-diphenyl-2-picrylhydrazyl which allowed the identification of antioxidants with different action rates. The results show that defoliation caused an increase in the phenolic acid (hydroxycinnamic and hydroxybenzoic acids) and flavonol concentrations of berries without changes in the composition. Both ascorbate and antioxidant activity were also enhanced in the berries from defoliated vines. Besides increasing the number of fast-rate antioxidants, leaf removal resulted in the formation of intermediate-rate ones. In the Trebbiano variety, leaf removal in the post fruit set may represent an effective strategy to enhance the phenolic composition and the antioxidant defense system of berries.

Post-veraison different frequencies of water deficit strategies enhance Reliance grapes quality under root restriction

In this study, two water deficit treatments in the same amount of water but with different frequencies (T1: 2.5 L per 4 d and T2: 5 L per 8 d) were performed on Reliance grapevines from veraison until harvest to explore their effects on grape berries quality under root restriction. Results showed that glucose, fructose and sucrose contents were increased, while malic acid, tartaric acid and citric acid contents were decreased under two treatments. Meanwhile, water deficits also promoted the accumulation of phenylalanine and proline. For phenols, anthocyanins, resveratrol and flavonols contents in the water deficit groups were significantly higher than those in the control group. In addition, two water deficit treatments increased the characteristic aromas contents, especially the esters contents. Overall, T2 treatment had a better effect than T1 treatment. This study provided an idea for improving water use efficiency and grape quality.

Improving the Antioxidant Activity and Flavor of Faba (Vicia faba L.) Leaves by Domestic Cooking Methods.

Faba leaves are an unusual vegetable which contain not only a range of functional phytochemicals, but also certain undesirable flavors, which limit their consumption. In this study, several cooking methods (microwaving, roasting, steaming, and boiling), which are expected to reduce the odd flavors, were evaluated in terms of both health benefit effects and odd flavor factors, including antioxidant activities and the content of non-volatile and volatile organic compounds (VOCs). A cooking time of 5 min was selected because of the high content of l-dopa (l-3,4-dihydroxyphenylalanine) and aim of reducing the undesirable flavors of the cooked faba leaves. Microwaving and steaming significantly increased the l-dopa content by 24% and 19%, respectively. Roasting specifically increased the content of flavonols, exhibiting a 28% increase of kaempferol-3-O-arabinoside-7-O-rhamnoside, representatively, whereas boiling decreased about 50% of most phytochemicals evaluated. Microwaving and steaming treatments significantly increased the antioxidant activities. The l-dopa content and antioxidant activities of the processed faba leaves were strongly positively correlated with either an R2 = 0.863 of DPPH radical scavenging activity or an R2 = 0.856 value of ABTS radical scavenging activity, showing that l-dopa was a key antioxidant. All cooking methods potentially improved the flavor of the cooked faba leaves compared with that of the fresh leaves, because they significantly reduced the contents of VOCs such as alcohols, aldehydes, and ketones. These VOCs were the main components (>90%) in the fresh leaves. Adverse aromatic hydrocarbons were newly formed by the microwaving treatment, typically producing p-xylene, which is known to be a harmful dose-dependent compound, but they were not detected in leaves processed by the other cooking methods; therefore, although microwaving efficiently increased antioxidant activity, the chemical safety of the aromatic hydrocarbons produced need further study.

Bottle Aging Affected Aromatic and Phenolic Wine Composition More than Yeast Starter Strains

Volatile and phenolic compounds play a key role in the sensory properties of wine, especially aroma and color. During fermentation, yeasts produce enzymes that affect the skin’s phenolic compounds extraction and synthesize some of the most important wine volatile compounds. Generally, selected yeasts of the Saccharomyces cerevisiae (Sc) strains are inoculated, which are responsible for carrying out the wine fermentation, enhancing and highlighting its sensory characteristics and contributing to help achieve the wine typicity, according to the winemaker’s criteria. After fermentation, all wines require aging in a bottle to modulate their composition and stability over time. Thus, four different Sc strains (Sc1–Sc4) were inoculated into tanks with Tempranillo grapes to carry out, in duplicate, their fermentation and subsequent aging in bottles (9 months), comparing the aromatic and phenolic composition between them. Results showed differences in the fermentation process (kinetic, ethanol yield), CI, TPI and content of alcohols, esters, anthocyanins, flavonols and flavanols in wines from the different Sc strains studied. Moreover, in the content in wines of most groups of aromas and phenols, except for total acetate esters and flavonols, aging in a bottle had more influence than the yeast strain used for fermentation.

Soil and climate effects on winter wine produced under the tropical environmental conditions of southeastern Brazil

Southeastern Brazil is an emergent region in terms of the production of high-quality fine wines. To contribute to typicity assessment, the soils (morphology, mineralogy, chemical and physical analyses), parent material (geologic maps and portable X-ray fluorescence spectrometry) and climate (temperature and precipitation) were characterized in seven vineyards located in the state of Minas Gerais and São Paulo, Brazil, by carrying out state-of-the-art terroir analysis and assessing the environmental variations of the study sites. A soil profile was described and sampled in the central part of each vineyard. Principal Component Analysis (PCA) biplots were used to analyze the relationships between these factors and the composition of wines (2016, 2017 and 2018 harvests) produced from Syrah in commercial vineyards in different municipalities of Três Corações (TC), Cordislândia (COR), Andradas (AND), São Sebastião do Paraíso (SSP), Três Pontas (TP), Espírito Santo do Pinhal (PIN) and Itobí (ITO). The vineyards were grouped according to soil and climate characteristics. Group A was composed of COR, AND and PIN vineyards, which exhibited the highest correlation with soil Al3+ content and accumulated rainfall. The group’s wines had the lowest ash alkalinity, total polyphenol index (TPI) and pH values and the highest fixed acidity. Group B consisted of the TP and TC vineyards, which had the highest soil organic matter and boron contents and the highest thermal amplitude with similar values (15.4 °C in TC and 15.2 °C in TP); their wines showed average composition. Group C comprised ITO alone, which was characterized by the shallowest and least developed soils. Its wine had the highest flavonol content and high dry extract, color intensity, TPI, alcohol content and sugar values. Group D contained the SSP vineyard, in which the soil subsurface horizons were correlated with the highest wine pH. Late harvest in this vineyard caused the most dehydration of grapes and consequent concentration of most wine compounds (human effect on terroir). The terroir information produced in this study adds substantial value to the wines produced under the tropical environmental conditions of southeastern Brazil, for which such studies are very rare. By characterizing the natural factors (soil, soil parent material and climate) and human factors (vineyard management and wine characteristics) related to terroir, this study can also provide historical information about the wine from this emergent region (the historical factors). In addition, its results can be used to guide producers in their choice of vineyard cultivation sites according to preference in wine composition.

Transcriptome and metabolome changes in Chinese cedar during cold acclimation reveal the roles of flavonoids in needle discoloration and cold resistance

Cryptomeria fortunei growth and development are usually affected by low temperatures. Despite the evergreen nature of this species, most needles turn yellowish-brown in cold winters. The underlying discoloration mechanisms that cause this phenomenon in response to cold acclimation remain poorly understood. Here, we measured the pigment content and ultrastructure of normal wild-type (Wt) and evergreen mutant (GM) C. fortunei needles and performed integrated transcriptomic and metabolomic analyses to explore potential discoloration mechanisms. The results showed that the needle chlorophyll content of these two genotypes decreased in winter. Wt needles showed greater decrease in the chlorophyll content and local destruction of chloroplast ultrastructure and contained larger amounts of flavonoids than GM needles, as shown by metabolomics analysis. We subsequently identified key differentially expressed genes in the flavonoid biosynthesis pathway and observed significantly upregulated flavonol synthase expression in Wt needles compared with GM needles that significantly increased the anthoxanthin (flavones and flavonols) content, which is likely a key factor underlying the difference in needle color between these two genotypes. Therefore, flavonoid metabolism may play important roles in the cold resistance and needle discoloration of C. fortunei, and our results provide an excellent foundation for the molecular mechanism of C. fortunei in response to cold stress.