Concentrations Of Total Phenolic Acids Research Articles

Content of Phenolic Acid and Yielding of Hybrid Wheat in Response to Growing Year Under Integrated Management

Abstract Wheat grain has health-promoting properties that are related to the content of phenolic acids in its composition, among which ferulic acid, syringic acid, p-coumaric acid and vanillic acid predominate acting as potent natural antioxidants. The study evaluated the phenolic acid (PA) content and grain yield of hybrid wheat genotypes (Hyland, Hywin) compared to the common variety (Patras), grown under an integrated system at two nitrogen rates of 60 (N60) and 120 (N120) kg·ha−1, under varying hydrothermal conditions during three growing seasons. The effects of genotype, cultivar and the interaction of cultivar and hydrothermal conditions on the phenolic acid profile, except for synapic acid, phydroxybenzoic acid and salicylic acid, and grain yield were confirmed in favour of the hybrid cultivars. The concentration of total phenolic acids (TPAs) and ferulic acid in the grain of the hybrid cultivar Hyland was higher and, in addition, greater yield stability of this cultivar under varying hydrothermal conditions was shown in the analysed years of the study. The grain of the common variety Patras was characterised by advanced content of p-hydroxybenzoic acid, and that of the hybrid variety Hywin by p-coumaric, caffeic and syringic acids. Higher TPAs content and lower grain yield of the varieties were observed in the 2018/2019 drought season. Higher nitrogen fertilisation (N120) compared to N60 significantly increased TPAs content and grain yield of Hyland and Hywin hybrid varieties. Fertilisation with N120 compared to N60 increased TPAs content by 4.2% and promoted higher concentrations of ferulic and syringic acids in the wheat cultivars tested.

Effect the accumulation of bioactive constituents of a medicinal plant (Salvia Miltiorrhiza Bge.) by arbuscular mycorrhizal fungi community

BackgroundArbuscular mycorrhizal fungi (AMF) form symbiotic relationships with various terrestrial plants and have attracted considerable interest as biofertilizers for improving the quality and yield of medicinal plants. Despite the widespread distribution of AMFs in Salvia miltiorrhiza Bunge's roots, research on the impact of multiple AMFs on biomass and active ingredient accumulations has not been conducted. In this study, the effects of five native AMFs (Glomus formosanum, Septoglomus constrictum, Rhizophagus manihotis, Acaulospora laevis, and Ambispora gerdemannii) and twenty-six communities on the root biomass and active ingredient concentrations of S. miltiorrhiza were assessed using the total factor design method.ResultsThirty-one treatment groups formed symbiotic relationships with S. miltiorrhiza based on the pot culture results, and the colonization rate ranged from 54.83% to 89.97%. AMF communities had higher colonization rates and total phenolic acid concentration than single AMF, and communities also appeared to have higher root fresh weight, dry weight, and total phenolic acid concentration than single inoculations. As AMF richness increased, there was a rising trend in root biomass and total tanshinone accumulations (ATTS), while total phenolic acid accumulations (ATP) showed a decreasing trend. This suggests that plant productivity was influenced by the AMF richness, with higher inoculation benefits observed when the communities contained three or four AMFs. Additionally, the affinities of AMF members were also connected to plant productivity. The inoculation effect of closely related AMFs within the same family, such as G. formosanum, S. constrictum, and R. manihotis, consistently yielded lower than that of mono-inoculation when any combinations were applied. The co-inoculation of S. miltiorrhiza with nearby or distant AMFs from two families, such as G. formosanum, R. manihotis, and Ac. laevis or Am. gerdemannii resulted in an increase of ATP and ATTS by more than 50%. AMF communities appear to be more beneficial to the yield of bioactive constituents than the single AMF, but overall community inoculation effects are related to the composition of AMFs and the relationship between members.ConclusionThis study reveals that the AMF community has great potential to improve the productivity and the accumulation of bioactive constituents in S. miltiorrhiza, indicating that it is an effective way to achieve sustainable agricultural development through using the AMF community.

Analysis of the phytochemical components of Prunella vulgaris using high-performance liquid chromatography quadrupole time-of-flight mass spectrometry combined with molecular networking and assessment of their antioxidant and anti-α-glucosidase activities.

Prunella vulgaris has long been used in traditional medicine and is consumed as a tea in China. Here, the total phenolic and flavonoid concentrations of plants from different geographical regions were measured. It was found that the total phenolic acid concentration ranged from 4.15 to 8.82 g of gallic acid equivalent per 100 g of dry weight (DW), and the total flavonoid concentration was 4.67-7.33 g of rutin equivalent per 100 g DW. Antioxidant activities were measured using 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt, and the results ranged from 73.47% to 94.43% and 74.54% to 93.39%, respectively, whereas α-glucosidase inhibition was between 75.31% and 95.49%. Correlation analysis showed that the total flavonoids in P. vulgaris had superior antioxidant and anti-α-glucosidase activities compared to the total phenolic compounds. The active components of P. vulgaris were analyzed using high-performance liquid chromatography quadrupole time-of-flight mass spectrometry combined with both classical molecular networking and feature-based molecular networking on the Global Natural Products Social platform, identifying 32 compounds, namely 14 flavonoids, 12 phenolic compounds, and 6 other chemical components. These results could provide useful information on the use of P. vulgaris as a functional tea.

Concentration of Phenolic Compounds and Phenolic Acids of Various Spelt Cultivars in Response to Growing Years

The aims of this study were to evaluate and compare the radical scavenging activities (DPPH), phenolic concentrations and concentrations of selected phenolic acids (PAs) of spelt cultivars and breeding lines with common wheat in a three-year controlled field experiment under conditions of organic farming. No significant variations were observed in the total and free DPPH of Altgold, Ebners Rotkorn, Ostro and PN-1-36 with common wheat. The total DPPH ranged from 52.13% to the lowest value of 44.01% in Franckenkorn. Total, free and bound phenolic concentrations were the highest for common wheat (1902.55 µg FAE g−1 DM of total), while all spelt cultivars achieved significantly lower values (from 1434.94 µg FAE g−1 DM in Franckenkorn to 1650.22 µg FAE g−1 DM in Ebners Rotkorn). Bound phenolic compounds represented 86.3% of the total ones. An extremely dry and warm ripening period had a negative impact on the synthesis of phenolic compounds. The highest concentration of total PAs was observed in spelt Ebners Rotkorn (681.75 µg g−1 DM) and the lowest in common wheat (396.05 µg g−1 DM). The total share of free and bound PAs was 5.7% and 74.8%, respectively. The extremely dry and very warm grain filling period had a more evident negative impact on the concentration of free PAs compared to bound forms. The dominant free PA was ferulic (70.48%), followed by syringic (9.30%), p-HBA (5.59%), sinapic acid (5.40%), salicylic (4.18%), p-coumaric acid (3.22%) and caffeic acid (1.93%). Spelt cultivar Ebners Rotkorn was distinguished by the highest concentration of free and bound forms of PAs.

Response of different cultivars of apricots to gamma irradiation under different storage conditions

A study was carried out to evaluate the physicochemical and phytochemical characteristics of various apricot cultivars (CITH-1, CITH-2, and Tilton) as well as the effect of gamma irradiation on their quality and shelf life. After harvesting at the pre-climacteric stage from the Central Institute of Temperate Horticulture, J & K (UT), apricot cultivars were gamma-irradiated in the dosage range of 0.25–1.0 kGy at the Bhaba Atomic Research Centre (BARC), Srinagar, and then stored at ambient temperature (25 ± 2 °C, RH 70–80%) and refrigerated temperature (3 ± 1 °C, RH 80–85%). The apricots were evaluated for their physicochemical and phytochemical composition. According to the HPLC analysis, the total polyphenol content of the cultivars differed significantly (p < 0.05), with Tilton having the highest total phenolic acid concentration of 5.85 mg/kg FW, followed by CITH-1 (5.14 mg/kg FW) and CITH-2 (3.25 mg/kg FW). In terms of lower weight loss, inhibition of enzyme activity, colour values, and maintaining quality and extending storage stability, irradiation at 0.25 kGy and 0.5 kGy was found to be significantly (p < 0.05) more effective than 0.75 kGy and 1.0 kGy. At dose levels of 0.5 kGy and 0.75 kGy, gamma irradiation was found to be significantly (p < 0.05) efficient in maintaining the firmness and bio-yield point without affecting overall acceptability. However, the 1.0 kGy dosage was found to be ineffective in delaying the occurrence of fruit rot and prolonging shelf life in both ambient and refrigerated storage. Thus, low-dose gamma radiation in the range of 0.25 kGy–0.75 kGy can be used to improve the quality and shelf life of apricots while also enhancing their therapeutic constituents intact for up to 21 days at ambient storage and 42 days under refrigerated conditions.

Nutritional quality characterization of a set of durum wheat landraces from Iran and Mexico

Wheat grain represents an important source of bioactive components that are associated with different health benefits, notably: dietary fibers, micronutrients and phytochemicals. However, despite the importance of these components, limited data are available on their content and composition, especially in durum wheat. In this study, 82 durum wheat landraces from Iran and Mexico were analyzed for arabinoxylan, iron, zinc, phytate and phenolic acids content. In general, wide variation was identified among landraces for these traits. Specifically, values ranging from 1.4 to 2.7% and 0.3–1.0% were detected for total and water-extractable arabinoxylans, respectively, in flour. In the case of micronutrients varied from 32.7 to 46.1 mg/kg (iron) and from 46.7 to 83.9 mg/kg (zinc) in grain. Phytate, a major component limiting micronutrient bioavailability, varied from 0.7 to 1.1% in whole-meal flour and the resulting phytate:iron and phytate:zinc molar ratios were 13.7–26.6 and 11.6–21.9, respectively, with more than 70% of the landraces exhibiting a relatively high Zn bioavailability. Seven phenolic acids were identified, with a variation in total phenolic acid concentration ranging from 279 μg/g to 845 μg/g in whole-meal flour. Overall, these results indicate that the landraces analyzed here could serve as useful genetic resources for the improvement of wheat nutritional quality in breeding programs.

Effects of phenolic acids on soil nitrogen mineralization over successive rotations in Chinese fir plantations

Phenolic acids are secondary metabolites of plants that significantly affect nutrient cycling processes. To investigate such effects, the soil available nitrogen (N) content, phenolic acid content, and net N mineralization rate in three successive rotations of Chinese fir plantations in subtropical China were investigated. Net N mineralization and nitrification rates in soils treated with phenolic acids were measured in an ex situ experiment. Compared with first-rotation plantations (FCP), the contents of total soil nitrogen and nitrate in second (SCP)- and third-rotation plantations (TCP) decreased, and that of soil ammonium increased. Soil net N mineralization rates in the second- and third-rotation plantations also increased by 17.8% and 39.9%, respectively. In contrast, soil net nitrification rates decreased by 18.0% and 25.0%, respectively. The concentrations of total phenolic acids in the FCP soils (123.22 ± 6.02 nmol g−1) were 3.0% and 17.9% higher than in the SCP (119.68 ± 11.69 nmol g−1) and TCP (104.51 ± 8.57 nmol g−1, respectively). The total content of phenolic acids was significantly correlated with the rates of net soil N mineralization and net nitrification. The ex situ experiment showed that the net N mineralization rates in soils treated with high (HCPA, 0.07 mg N kg−1 day−1) and low (LCPA, 0.18 mg N kg−1 day−1) concentrations of phenolic acids significantly decreased by 78.6% and 42.6%, respectively, comparing with that in control (0.32 mg N kg−1 day−1). Soil net nitrification rates under HCPA and LCPA were significantly higher than that of the control. The results suggested that low contents of phenolic acids in soil over successive rotations increased soil net N mineralization rates and decreased net nitrification rates, leading to consequent reductions in the nitrate content and enhancement of the ammonium content, then resulting in enhancing the conservation of soil N of successive rotations in Chinese fir plantation.

Determination of phenolic acid profiles by HPLC-MS in vegetables commonly consumed in China.

This study aimed to establish a precise HPLC-MS approach to determine the concentrations and distribution of major phenolic acids in six categories of vegetables that are commonly consumed in China. We detected 17 phenolic acids within 15 min under optimized conditions. The method showed detection limits varying from 0.008 mg/L to 0.042 mg/L, average recoveries ranging from 71.0% to 110.7%, and a RSD of ≤9.98%. The average concentrations of total phenolic acids followed the order of flower > root > leafy > stem > bean > fruit vegetables. The phenolic acids were more abundant in the leafy, root, and stem vegetables than in the other vegetable samples. Furthermore, the levels of isoferulic acid, p-coumaric acid, and ferulic acid were greater than those of other phenolic acids in the vegetables. Free soluble phenolic acids were the dominant species in all vegetables (P < 0.001), except in the stem vegetables (P < 0.027).

Characterization of Free, Conjugated, and Bound Phenolic Acids in Seven Commonly Consumed Vegetables.

Phenolic acids are thought to be beneficial for human health and responsible for vegetables’ health-promoting properties. Free, conjugated, and bound phenolic acids of seven commonly consumed vegetables, including kidney bean, cow pea, snow pea, hyacinth bean, green soy bean, soybean sprouts and daylily, from the regions of Beijing, Hangzhou, and Guangzhou, were identified and quantified by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Three vegetables, namely green soy bean, soybean sprouts, and daylily (Hemerocallis fulva L.), from the Beijing region contained higher concentrations of total phenolic acids than those from the Hangzhou and Guangzhou regions. The results indicated that the phenolic acid content in the seven vegetables appeared to be species-dependent. The highest content of phenolic acids was found in daylily, followed by green soy bean, while the least amounts were identified in kidney bean and hyacinth bean. Typically, phenolic acids are predominantly found in conjugated forms. Principle component analysis (PCA) revealed some key compounds that differentiated the seven vegetables. Green soy bean, compared to the other six vegetables, was characterized by higher levels of syringic acid, ferulic acid, vanillic acid, and sinapic acid. Other compounds, particularly p-coumaric acid, neochlorogenic acid, and caffeic acid, exhibited significantly higher concentrations in daylily. In addition, p-coumaric acid was the characteristic substance in cow pea. Results from this study can contribute to the development of vegetables with specific phytochemicals and health benefits.

The Influence of Prefermentative Addition of Gallic Acid on the Phenolic Composition and Chromatic Characteristics of Cabernet Sauvignon Wines.

In this study, the prefermentative addition of gallic acid in Cabernet Sauvignon red winemaking was performed. The influence of gallic acid addition on wine phenolic composition, the ratio of copigmentation, and the color parameters were monitored throughout the winemaking process. The results showed that the prefermentative addition of gallic acid enhanced the extraction of total anthocyanins and the copigmentation effect, producing wines with more darkness, redness, yellowness, and saturation. Moreover, the addition of gallic acid contributed to the concentration of total phenolic acids. However, it had a negative effect on the concentrations of flavonols and flavan-3-ols in the final wines. Thus, the prefermentative addition of gallic acid at appropriate levels might be a promising enological technology to obtain wines with high color quality and aging potential.

Changes in the Phytochemicals Composition during Bread and Pancake Preparations from Whole and Refined Wheat Flours

In this study, we investigated the changes in the level of phytochemicals during bread and pancake preparations from refined and whole‐wheat flours of two wheat varieties. Phytochemicals were extracted with ultrasonic (UAE) and microwave (MAE) assisted extractions followed by analyses with spectroscopic and chromatographic methods. Comparison of the efficacy of two methods for hydrolysis and extraction of phenolic acids showed that yield of total phenolic acids (TPA) was ~10–25% higher among all varieties using UAE as compared to MAE. Most (&gt; 90%) of the phenolic acids in all wheat flour samples existed in insoluble bound form. Ferulic acid, lutein and α‐tocopherol were the predominant phenolic acid, carotenoid, and tocopherol, respectively, extracted from all fractions. The quantities of phenolic acids, carotenoids, and tocopherols were significantly higher in all fractions made from whole wheat flour than their corresponding refined wheat flour fractions. Ferulic acid was the most abundant phenolic acid, accounting for a mean of 85% and 90% of TPA among all RF (refined flour) and WW (whole wheat) samples, respectively. The concentration of TPA did not significantly changed during pancake and bread preparation. However, concentration of tocopherols and carotenoids was reduced. Thus the processing of wheat samples has varying effects on the concentration of phytochemicals in raw and finished products. This project was partially supported by the Agriculture and Food Research Initiative Grant no. 2009‐02347 from the USDA National Institute of Food and Agriculture.Support or Funding InformationThis project was partially supported by the Agriculture and Food Research Initiative Grant no. 2009‐02347 from the USDA National Institute of Food and Agriculture.

Genetic variation for phenolic acids concentration and composition in a tetraploid wheat (Triticum turgidum L.) collection

Phenolic acid intake through the consumption of whole-wheat foods provides important health benefits associated with reduced risks of cardiovascular diseases and colon cancer. The genetic variation for phenolic acids was extensively studied in common wheat, but a comprehensive survey in tetraploid wheat is lacking. In this study we evaluated the genetic variability for individual and total phenolic acids concentration existing in a large collection of tetraploid wheat (Triticum turgidum L.). A 2-year evaluation was undertaken on the whole-meal flour of 111 genotypes belonging to seven T. turgidum subspecies including cultivars, landraces and wild accessions. Durum cultivars [T. turgidum subsp. durum (Desf.) MacKey], had the highest average concentration of total phenolic acids (828.7 μg g−1 dm in 2012; 834.5 μg g−1 dm in 2013) with amounts varying from 550.9 μg g−1 dm to 1701.2 μg g−1 dm, indicating a variation of greater than threefold fold. The lowest concentration of phenolic acids was found in T. turgidum subsp. dicoccum (Schrank ex Schubler) Thell. Rivet wheat (T. turgidum L. subsp. turgidum) had phenolic acid concentrations similar to those in durum, but less variation was noted among the accessions. On the other hand, the accessions of the four remaining subspecies showed lower phenolic acid concentrations and variation among the accessions as compared to durum. A total of six phenolic acids were identified across the wheat genotypes. The effects of genotype, year and year × genotype were estimated by ANOVA and resulted significant for all phenolic acids. The ratio of genotypic variance to total variance suggested the possibility of improving phenolic acid content in elite wheat germplasm through appropriate breeding programs. Moreover, significant correlations between phenolic acids and other quality characteristics of the grain were detected.

Phytochemical Profile and Antiproliferative Activity of Dough and Bread Fractions Made from Refined and Whole Wheat Flours

Phytochemical profile (phenolic acids, carotenoids, and tocopherols) and antiproliferative properties of bread processing fractions, including the dough, crumb, and upper crust made from refined wheat and whole wheat flours were analyzed for two wheat cultivars. Ferulic acid, lutein, and α‐tocopherol were the predominant phenolic acid, carotenoid, and tocopherol, respectively, extracted from all fractions. The levels of all phytochemicals in whole wheat samples were over eightfold higher than their corresponding refined wheat samples. The concentrations of total phenolic acids (soluble and insoluble bound) were higher in the upper crust of refined (∼60–90%) and whole wheat (∼15–40%) breads than their corresponding dough fractions. However, the dough of whole wheat had higher levels of tocopherols and carotenoids compared with the crumb and upper crust, suggesting that phenolic acids were relatively stable during baking, whereas tocopherols (∼25–80%) and carotenoids (∼20–80%), were partially degraded. The antiproliferative activity of whole wheat bread extracts against HT‐29 cancer cells was weakly correlated with total phenolic acids but showed no correlations with total carotenoid and total tocopherol contents.

The influence of pectolytic enzyme addition and prefermentative mash heating during the winemaking process on the phenolic composition of Okuzgozu red wine

The effects of pectolytic enzyme addition and mash heating prior to fermentation on the phenolic component of Okuzgozu red wine during the winemaking and ageing processes were investigated. In general, the highest concentration of total phenolics was found in the mash-heated wines, whereas the total flavan-3-ol and total anthocyanin contents in all of the wines, decreased notably during the winemaking and ageing processes. As determined by HPLC, hydroxycinnamic acids were the major phenolic acids in the red wines. After 6months in the bottle, the enzyme-treated wines had lower phenolic acid concentrations than had the control and mash-heated wines, but no significant (p<0.05) differences were found in the concentration of total phenolic acids between the control and mash-heated wines. All of the phenolic acid levels decreased with the winemaking and ageing processes whereas only gallic acid increased. The wines treated by the pectolytic enzyme addition had a lower monomeric flavan-3-ol content than had the other wines, and the amount of monomeric anthocyanins extracted did not increase with the addition of enzymes.

Prediction of ‘Nules Clementine’ mandarin susceptibility to rind breakdown disorder using Vis/NIR spectroscopy

The use of diffuse reflectance visible and near infrared (Vis/NIR) spectroscopy was explored as a non-destructive technique to predict ‘Nules Clementine’ mandarin fruit susceptibility to rind breakdown (RBD) disorder by detecting rind physico-chemical properties of 80 intact fruit harvested from different canopy positions. Vis/NIR spectra were obtained using a LabSpec® spectrophotometer. Reference physico-chemical data of the fruit were obtained after 8 weeks of storage at 8°C using conventional methods and included RBD, hue angle, colour index, mass loss, rind dry matter, as well as carbohydrates (sucrose, glucose, fructose, total carbohydrates), and total phenolic acid concentrations. Principal component analysis (PCA) was applied to analyse spectral data to identify clusters in the PCA score plots and outliers. Partial least squares (PLS) regression was applied to spectral data after PCA to develop prediction models for each quality attribute. The spectra were subjected to a test set validation by dividing the data into calibration (n=48) and test validation (n=32) sets. An extra set of 40 fruit harvested from a different part of the orchard was used for external validation. PLS-discriminant analysis (PLS-DA) models were developed to sort fruit based on canopy position and RBD susceptibility. Fruit position within the canopy had a significant influence on rind biochemical properties. Outside fruit had higher rind carbohydrates, phenolic acids and dry matter content and lower RBD index than inside fruit. The data distribution in the PCA and PLS-DA models displayed four clusters that could easily be identified. These clusters allowed distinction between fruit from different preharvest treatments. NIR calibration and validation results demonstrated that colour index, dry matter, total carbohydrates and mass loss were predicted with significant accuracy, with residual predictive deviation (RPD) for prediction of 3.83, 3.58, 3.15 and 2.61, respectively. The good correlation between spectral information and carbohydrate content demonstrated the potential of Vis/NIR as a non-destructive tool to predict fruit susceptibility to RBD.

Phenolic Acids in Wheat Varieties in the HEALTHGRAIN Diversity Screen

The amounts and compositions of free, conjugated, bound, and total phenolic acids were determined in 175 samples of wheat flour grown on a single site in 2005. The highest contents of total phenolic acids were found in flours of winter wheat (1171 microg/g) with average levels of 658 microg/g total phenolics across all of the wheat genotypes. Winter wheats showed a range of >3.5-fold across the concentration range for total phenolic acids. Spelt genotypes displayed the narrowest (1.9-fold) range of total phenolic acid concentration. The concentrations of phenolic acids in the different phenolic acid fractions were in the order bound > conjugated > free, with bound phenolic acids making up around 77% of the total phenolic acid concentration and free phenolic acids constituting between 0.5 and 1%. The results indicate that there is genetic diversity in phenolic acid content and that it should be possible to selectively breed for lines with high contents of phenolic components.

Toward the Fingerprinting of Wines: Cultivar-Related Patterns of Polyphenolic Constituents in Ontario Wines

The concentrations of 15 polyphenols (the phenolic acids gentisic, vanillic, ferulic, m-coumaric, p-coumaric, caffeic, and gallic acid; the trihydroxystilbenes cis- and trans-resveratrol and cis- and trans-polydatin; and the flavonoids, catechin, epicatechin, quercetin, and morin) were measured in wines from a range of white (Chardonnay, Riesling, Seyval Blanc, Vidal) and red (Pinot Noir, Cabernet Sauvignon, Cabernet Franc, Merlot, Gamay Noir) cultivars grown in the viticultural region of Niagara, ON, Canada, to determine whether significant and characteristic differences in the content and relative patterns of individual polyphenols could be identified among the wines of various cultivars. An assay involving solid-phase extraction followed by derivatization and gas chromatography/mass spectrometry was used to quantify the polyphenols. Overlapping values between red and white wines were observed for gentisic, ferulic, p-coumaric, and caffeic acid; the concentrations of the other polyphenols were 5−20-fold higher in red wines, apart from m-coumaric acid and morin, which could not be detected in any of these wines. Ferulic acid was the highest of all phenolic acids in Riesling wine; in wines from the other three white grape cultivars, caffeic acid and p-coumaric acid were the highest, with caffeic acid being the highest in Chardonnay and Vidal wines and p-coumaric acid in those from Seyval Blanc. The latter had the lowest mean total phenolic acid concentration (0.035 mmol/L) compared with Chardonnay, Vidal, and Riesling (0.052, 0.066, and 0.075 mmol/L, respectively). The individual phenolic acids demonstrated a similar pattern among all of the red wines analyzed, with gallic acid being the highest and caffeic acid the second highest. Their mean total phenolic acid concentrations spanned a narrow range from 0.200 mmol/L (Gamay Noir) to 0.250 mmol/L (Pinot Noir). Of the hydroxystilbene components, Pinot Noir wines were notable in having by far the highest polydatin concentrations, whereas their concentrations of free resveratrol isomers were among the lowest in this study. Of the flavonoid components, Pinot Noir wines were highest in catechin and epicatechin concentrations, whereas wines from Cabernet Sauvignon that were lowest in the latter two flavonoids had the highest quercetin concentrations. Keywords: Phenolic acids; hydroxystilbenes; flavonoids; gas chromatography/mass spectrometry; Vitaceae

Distribution of insoluble bound phenolic acids in barley grain

AbstractInsoluble bound phenolic acids were analysed by g.l.c. and by h.p.l.c. in eight abraded fractions of barley grain. Vanillic, p‐coumaric, ferulic and diferulic acids were identified in all the fractions. Ferulic and p‐coumaric acids were quantitatively the most important. The outer layers, comprising husks, pericarp, testa and aleurone cells, contained the highest concentrations of total phenolic acids (0.6–0.9%) while their concentrations were considerably lower in the endosperm layers (0.1% or less). Calculated on the basis of the cell wall content in the fractions, the highest concentration of ferulic acid was found in fractions enriched with aleurone cells while the highest concentration of p‐coumaric acid was found in fractions containing high levels of husks.

Changes in microbial biomass and activity in soils amended with phenolic acids

The phenolic acids p-hydroxybenzoic, ferulic, caffeic and vanillic acid, were added to soil of the Countesswells series that had been fallow or carried crops of potatoes, peas or barley for two consecutive years. Changes in phenolic acid concentration, the soil biomass, the respiration rate, and soil amylase activity were measured over 28 days. All the phenolic acids were sorbed by the soils which was generally in the order caffeic > ferulic = vanillic > hydroxybenzoic acid. The phenolic acids stimulated soil respiration and increased the biomass as determined by the substrate-induced respiration method. but the fumigation method of biomass assessment gave anomalous results. The soil amylase activity was initially increased by phenolic acid amendments but soon decreased, and after 7 days was less than in non-amended soil although activity had increased again after 28 days. The rates of respiration and the total phenolic acid concentrations were similar to unamended controls after 28 days. The immediate respiration response, measured 1–6 h after amendment, indicated that caffeic acid gave the largest initial response of the phenolic tested, this being 55–72% of that given by glucose. Soil from the potato plot showed the highest immediate response to the phenolic acid amendments measured as a proportion of the respiration response to glucose. The findings suggest that some crops stimulate the growth of phenolic-acid degrading organisms.

Behavior of phenolic substances in the decaying process of plants

Abstract Phenolic compounds in the soils collected from 6 paddy fields and 9 forests were surveyed quantitatively by gas chromatography. The results are as follows: 1) p-Coumaric, ferulic, vanillic, p-hydroxybenzoic, syringic, salicylic, and protocatechuic acids were detected in all soils. Among these acids, p-coumaric acid was present in the largest quantity in most of the soils. Gallic, caffeic, and sinapic acids, resorcinol, and phloroglucinol were not detected. 2) The total amounts of individual phenolic acids in the forest soils (34-632 ppm) were markedly higher than those in the paddy soils (10-26 ppm). p-Coumaric acid content went up to 188 ppm in the forest soils and up to 7 ppm in the paddy soils. The average concentration of total phenolic acids per weight of organic matter in the forest soils was about 2 times as high as that in the paddy soils. 3) In the paddy soils, the concentrations of p-hydroxybenzoic, vanillik, syringic, p-coumarie, and ferulic acids, which have no chelating ability, were considerably related to the pH and the carbon content of the soil, but the concentrations of protocatechuic and salicylic acids, which are chelating agents, were not related to those of the soil. Also in A horizons of forest soils, the concentrations of many phenolic acids were related to carbon content, but not to pH. 4) In a forest soil surveyed, the concentrations of individual phenolics decreased with increasing depth. However, the ratios of the amounts of individual phenolics to the carbon content increased with depth.