Total Ferulic Acid Research Articles

An Attempt to Identify the Low Molecular Feruloylated Oligosaccharides in Beer

Ferulic acid (4-hydroxy-3-methoxycinnamic acid), predominantly in ester form in arabinoxylan chains, is the main phenolic acid present in barley and malt. Only about 1% of the total ferulic acid in barley is present in the free form. A number of previous works concerned the contents of free and esterified ferulic acid in a broad range of popular beers, but there is little information about the possible composition of feruloylated oligosaccharides in beers. The aim of this preliminary work was to purify the feruloylated oligosaccharides from lager beers (by the means of preparative chromatography) followed by composition elucidation using TLC, HPLC with RI or UV detection and 1 H-NMR. Indeed, the qualitative analyses of isolated fractions from beer revealed that the fractions contained ferulic acid in the ester form (as proven after mild alkaline hydrolysis). It was also shown that molecular masses of oligosaccharides present in the purified beer fractions were similar to the masses of arabinose and xylooligosaccharides in the range of xylose to xylohexaose. Although a number of purified beer samples contained oligosaccharides of higher molecular masses, these were not further characterized. Taking under consideration the presented results, it can be concluded that beer can be a good source of feruloylated oligosaccharides, significant in the context of human health benefits.

Phenolic Antioxidants Richly Contained in Corn Bran Are Slightly Bioavailable in Rats

Phenolic acids (PAs) have been shown to be beneficial to human health and are found most abundantly in corn bran ( approximately 4%, w/w), one of the main dietary fibers. This study therefore evaluated the bioavailabilities of phenolic antioxidants ferulic acid (FA) and p-coumaric acid (PCA) in refined corn bran (RCB) by determining their recovery in the plasma, urine, and feces of rats fed a single meal of a RCB diet containing 5% RCB or adapted to the RCB diet for 10 days. In both studies, 0.4-0.5% of ingested FA and 1.2-2.3% of ingested PCA were recovered in rat urine. By contrast, approximately 81% of FA and approximately 64% of PCA ingested with the single meal were excreted through the rat feces within 3 days after the ingestion. On the other hand, after rats were fed the RCB diet, total FA (all forms of FA) was recovered in plasma at a concentration of 35.0 +/- 2.0 microg/L, total FA and total PCA were excreted through urine at levels of 155.4 +/- 5.8 and 50.9 +/- 6.6 microg/day, respectively. These parameters showed no significant change (P = 0.93, 0.09, and 0.66, respectively) after rats were fed the RCB diet continuously for up to 10 days. These results suggest that the PAs in RCB are bioavailable in rats. Their bioavailabilities, however, are relatively low compared with their high content in RCB and not improved by the adaptation for 10 days to the enriched RCB diet. Additionally, comparison with the results of other studies revealed that high contents of FA and, especially, diferulic acids in cereal bran, which act as cross-links between bran cell wall polysaccharides, may not improve but, rather, limit the bioavailabilities of PAs in vivo.

Valor nutritivo de plantas de milho (<em>Zea mays</em> L.) sem espigas

Chemical-bromatologic composition and in vitro digestibility of five corn genotypes (F2, Lu16, F271, Lu5 and Lu6) were evaluated in Druelle-France, an area of in 150 m2 with two repetitions. All evaluations used whole corn plants without ears. A randomized experimental design was used. The Lu16 genotype showed higher values for in vitro dry matter digestibility (69.82%) and cell wall digestibility (48.05%). Lu6 genotype showed the lowest value for in vitro dry matter digestibility (50.38%). Dry matter and cell wall digestibility were estimated by an indirect method and they were negatively affected by lignin contents, p-coumaric acid and total ferulic acid, serving as strong or weak links between lignin and hemicelluloses. Using multiple regression analysis, results showed that acid detergent fiber and acid detergent lignin explained 98% of in vitro dry matter digestibility results and 96% of cell wall digestibility estimated for equation. Esterified p-coumeric acid and acid detergent lignin explained 99% of cell wall digestibility results

Phenolic acid profiles and antioxidant activities of wheat bran extracts and the effect of hydrolysis conditions

Four different types of wheat bran were extracted and analyzed for phenolic acids using the Folin–Ciocalteu method and HPLC. The extracts and their hydrolysis products were also evaluated for their antioxidant activities. The total phenolic content of the red wheat bran was higher than that of the white wheat. We found that the majority of the phenolic acids existed in a bound form in wheat bran. These phenolic acids can be released by hydrolyzing the bran under alkaline or acidic conditions; however, the former was more efficient in the release of free phenolic acids than the latter. Ferulic, vanillic, and syringic acids were the major individual phenolic acids in the studied wheat bran. The main portion of the total ferulic acid was from alkaline hydrolysis. The alkaline hydrolysable fractions had greater antioxidant activities, while the acid hydrolysable fractions showed lower activities in both the red and white bran. The antioxidant activity of bran extract was stronger than that of free phenolic acids.

Assay of free ferulic acid and total ferulic acid for quality assessment of Angelica sinensis

Activity of Chinese Danggui (DG), the processed root of Angelica sinensis (Oliv.) Diels, is linked to the ferulic acid content but the stability of ferulic acid during extraction for medicinal use is not known. The stabilities of ferulic acid and coniferyl ferulate were evaluated in the extracts of DG using a variety of extraction solvents. These included various combinations and proportions of methanol, water, formic acid, 1 M aqueous hydrochloric acid and 2% sodium hydrogen carbonate (NaHCO 3) in water. Coniferyl ferulate was found liable to hydrolyze into ferulic acid in neutral, strongly acidic and basic solvents, where heat and water could facilitate this hydrolysis. However, the hydrolysis was relatively resisted in weakly organic acid. Based on the stability evaluation, two new terms, namely: free ferulic acid and total ferulic acid, were suggested and defined. Free ferulic acid refers to the natural content of ferulic acid in herbs. Total ferulic acid means the sum of free ferulic acid plus the amount of related hydrolyzed components. Meanwhile, the high-performance liquid chromatographic (HPLC) method was developed to assay free ferulic acid and total ferulic acid in DG using methanol–formic acid (95:5) and methanol–2% NaHCO 3 in water (95:5) as extraction solvents, respectively. Ten DG samples were investigated on their contents of free and total ferulic acid. The results indicated that the amount variety of free ferulic acid was larger than that of their counterparts, and the ratio of total ferulic acid to free ferulic acid was 4.07 ± 2.73 (mean ± SD, n = 10). The chemical assay of DG using total ferulic acid content would be a better choice to assess the herbal quality and was recommended.

Sporotrichum thermophile type C feruloyl esterase (StFaeC): purification, characterization, and its use for phenolic acid (sugar) ester synthesis

A feruloyl esterase (StFaeC) produced by Sporotrichum thermophile was purified to homogeneity. The native StFaeC was homodimer with a subunit of M r 23,000 and pI 3.1. The enzyme activity was optimal at pH 6.0 and 55 °C. The esterase displayed remarkable stability at pH 10.0 and retained 50% of its activity after 133 and 55 min at 55 and 60 °C, respectively. Determination of k cat/ K m revealed that the enzyme had a broad spectrum of activity against the (hydroxyl) cinnamate esters indicating a type C feruloyl esterase. The enzyme was active on substrates containing ferulic acid ester linked to the C-5 and C-2 linkages of arabinofuranose and hydrolysed 4-nitrophenyl-5- O- trans-feruloyl-α- l-arabinofuranoside three times more efficiently than 4-nitrophenyl-2- O- trans-feruloyl-α- l-arabinofuranoside. Ferulic acid was efficiently released from wheat bran when the esterase was incubated together with xylanase from S. thermophile (a maximum of 41% total ferulic acid released after 1 h incubation). StFaeC by itself could release FA but at a level almost 10-fold lower than that obtained in the presence of xylanase. The potential of StFaeC for the synthesis of various phenolic acid esters was examined using as a reaction system a ternary water–organic mixture consisting of n-hexane, 1-butanol and water. Also StFaeC catalyzed the transfer of the feruloyl group to l-arabinose in a similar system using t-butanol, with about a 40% conversion of l-arabinose to feruloylated derivative was achieved. This work is the first example of enzymatic feruloylation of a carbohydrate.

Bio-functional components in the processed pre-germinated brown rice by a twin-screw extruder

Development of a novel foodstuff from pre-germinated brown rice by a twin-screw extruder was investigated. The characteristics of the components of the materials and the products are as follows: (1) Pre-germinated brown rice was prepared by soaking in water for 72 h at 30 °C followed by drying to 13–15% moisture content at 15 °C in a low-humidity artificial weather-control room. Total dietary fiber, total ferulic acid and gamma-aminobutyric acid (GABA) contents of the pre-germinated brown rice were higher than those of ordinary brown rice or polished rice. (2) The pre-germinated brown rice was processed with a twin-screw extruder. The puffed pre-germinated brown rice contained more oryzanol, inositol, total ferulic acid and total dietary fibers compared with the un-puffed polished rice. The product prepared by the co-extrusion of pre-germinated brown rice (90%) and beer yeast (10%) contained more free amino acids, such as GABA, glycine, alanine, aspartic acid and glutamic acid, compared with polished rice, brown rice and puffed pre-germinated brown rice. (3) Extrusion cooking was shown to sterilize the germinated brown rice by the incubation test, which would lead to the development of consumer-oriented rice products in terms of food safety. (4) The wheat bread prepared with 30% of the puffed pre-germinated brown rice contained more GABA, free sugars, such as maltose, compared with the ordinary wheat bread. The extrudate bread was shown to be sweeter ( P < 0.05 ) and equivalently palatable ( P < 0.05 ) as a result of organoleptic test. These results show that novel foodstuff from the extruded pre-germinated brown rice would be acceptable to consumers or the food industry as a promising foodstuff containing more nutritional and bio-functional components than ordinary rice products.

Bioavailability and pharmacokinetics of caffeoylquinic acids and flavonoids after oral administration of Artichoke leaf extracts in humans

Extracts from artichoke leaves are traditionally used in the treatment of dyspeptic and hepatic disorders. Various potential pharmacodynamic effects have been observed in vitro for mono- and dicaffeoylquinic acids (e.g. chlorogenic acid, cynarin), caffeic acid and flavonoids (e.g. luteolin-7-O-glucoside) which are the main phenolic constituents of artichoke leaf extract (ALE). However, in vivo not only the genuine extract constituents but also their metabolites may contribute to efficacy. Therefore, the evaluation of systemic availability of potential bioactive plant constituents is a major prerequisite for the interpretation of in vitro pharmacological testing. In order to get more detailed information about absorption, metabolism and disposition of ALE, two different extracts were administered to 14 healthy volunteers in a crossover study. Each subject received doses of both extracts. Extract A administered dose: caffeoylquinic acids equivalent to 107.0 mg caffeic acid and luteolin glycosides equivalent to 14.4 mg luteolin. Extract B administered dose: caffeoylquinic acids equivalent to 153.8 mg caffeic acid and luteolin glycosides equivalent to 35.2 mg luteolin. Urine and plasma analysis were performed by a validated HPLC method using 12-channel coulometric array detection. In human plasma or urine none of the genuine target extract constituents could be detected. However, caffeic acid (CA), its methylated derivates ferulic acid (FA) and isoferulic acid (IFA) and the hydrogenation products dihydrocaffeic acid (DHCA) and dihydroferulic acid (DHFA) were identified as metabolites derived from caffeoylquinic acids. Except of DHFA all of these compounds were present as sulfates or glucuronides. Peak plasma concentrations of total CA, FA and IFA were reached within 1 h and declined over 24 h showing almost biphasic profiles. In contrast maximum concentrations for total DHCA and DHFA were observed only after 6-7 h, indicating two different metabolic pathways for caffeoylquinic acids. Luteolin administered as glucoside was recovered from plasma and urine only as sulfate or glucuronide but neither in form of genuine glucosides nor as free luteolin. Peak plasma concentrations were reached rapidly within 0.5 h. The elimination showed a biphasic profile.

Ferulic Acid Is Quickly Absorbed from Rat Stomach as the Free Form and Then Conjugated Mainly in Liver

Ferulic acid (FA) is one of the most abundant phenolic antioxidants in the human diet. Many studies have documented its beneficial properties. It is therefore essential to understand the absorption and metabolism of FA in detail. The purpose of this study was to confirm the hypothesis that FA is absorbed in rat stomach and metabolized mainly in the liver. We determined the recovery of FA and its metabolites (FA sulfate/glucuronides) in rat gastric contents, gastric mucosa, portal vein plasma, celiac arterial plasma, bile, and urine after 2.25 micromol FA was administered in 0.5 mL physiological saline and incubated for 25 min in situ in the stomach of rats. Within 25 min, 74 +/- 11% of the administered FA disappeared from the stomach; later, FA was recovered in both free and conjugated forms in plasma, bile, and urine. On the other hand, only free FA was detected in the gastric contents and mucosa; it was also detected in the portal vein plasma as 49 +/- 5% of the total FA (all forms of FA). However, the proportion of free FA in the celiac arterial plasma, bile, and urine decreased to 5-8%. These results indicate that FA can be quickly absorbed from the rat stomach, and then is likely metabolized mainly in the liver. Such novel information would be helpful in the use of FA as a nutrient supplement. For example, oral administration of FA in capsule form or in a form bonded with sugar esters may provide a more appropriate concentration of FA in the circulation, which may improve its proposed efficacy in preventing chronic disease.

Phytochemical profiles and antioxidant activity of wheat varieties.

Whole grain consumption has been associated with reduced risk of chronic diseases, such as cardiovascular diseases and cancer. These beneficial effects have been attributed to the unique phytochemicals of grains that complement those found in fruits and vegetables. Wheat is one of the major grains in the human diet; however, little is known about the inherent varietal differences in phytochemical profiles, total phenolic and carotenoid contents, or total antioxidant activities of different wheat varieties, which ultimately influence the associated nutritional and health benefits of wheat and wheat products. The objectives of this study were to determine the phytochemical profiles and total antioxidant activity for 11 diverse wheat varieties and experimental lines. The profiles included free, soluble-conjugated, and insoluble-bound forms of total phenolics, flavonoids, and ferulic acids and carotenoid content including lutein, zeaxanthin, and beta-cryptoxanthin. The results showed that total phenolic content (709.8-860.0 micromol of gallic acid equiv/100 g of wheat), total antioxidant activity (37.6-46.4 micromol of vitamin C/g), and total flavonoid content (105.8-141.8 micromol of catechin equiv/100 g of wheat) did not vary greatly among the 11 wheat lines. However, significant differences in total ferulic acid content (p < 0.05) and carotenoid content (p < 0.05) among the varieties were observed, with carotenoid content exhibiting the greatest range of values. Carotenoid content among the 11 wheat varieties exhibited 5-fold, 3-fold, and 12-fold differences in lutein, zeaxanthin, and beta-cryptoxanthin, respectively. A synthetic wheat experimental line, W7985, gave the lowest carotenoid concentrations of any of the genotypes in this study. Such large genotypic differences in carotenoid content may open up new opportunities for breeding wheat varieties with higher nutritional value.

Purification and characterization of a type B feruloyl esterase (StFAE-A) from the thermophilic fungus Sporotrichum thermophile.

A feruloyl esterase (StFAE-A) produced by Sporotrichum thermophile was purified to homogeneity. The purified homogeneous preparation of native StFAE-A exhibited a molecular mass of 57.0+/-1.5 kDa, with a mass of 33+/-1 kDa on SDS-PAGE. The pI of the enzyme was estimated by cation-exchange chromatofocusing to be at pH 3.1. The enzyme activity was optimal at pH 6.0 and 55-60 degrees C. The purified esterase was stable at the pH range 5.0-7.0. The enzyme retained 70% of activity after 7 h at 50 degrees C and lost 50% of its activity after 45 min at 55 degrees C and after 12 min at 60 degrees C. Determination of k(cat)/ K(m) revealed that the enzyme hydrolyzed methyl p-coumarate 2.5- and 12-fold more efficiently than methyl caffeate and methyl ferulate, respectively. No activity on methyl sinapinate was detected. The enzyme was active on substrates containing ferulic acid ester linked to the C-5 and C-2 linkages of arabinofuranose and it hydrolyzed 4-nitrophenyl 5- O- trans-feruloyl-alpha- l-arabinofuranoside (NPh-5-Fe-Ara f) 2-fold more efficiently than NPh-2-Fe-Ara f. Ferulic acid (FA) was efficiently released from destarched wheat bran when the esterase was incubated together with xylanase from S. thermophile (a maximum of 34% total ferulic acid released after 1 h incubation). StFAE-A by itself could release FA, but at a level almost 47-fold lower than that obtained in the presence of xylanase. The potential of StFAE-A for the synthesis of various phenolic acid esters was tested using a ternary water-organic mixture consisting of n-hexane, 1-butanol and water as a reaction system.

Purification and characterization of a Fusarium oxysporum feruloyl esterase (FoFAE-I) catalysing transesterification of phenolic acid esters

An extracellular feruloyl esterase (FoFAE-I) from the culture filtrates of Fusarium oxysporum F3 was purified to homogeneity by ion-exchange, hydrophobic interaction and gel filtration chromatographies. The protein corresponded to molecular mass and p I values of 31 kDa and 9.5, respectively. The enzyme was optimally active at pH 7.0 and 55 °C. The purified esterase was fully stable at pH 7.0–9.0 and temperature up to 30 °C. Determination of k cat/ K m revealed that the enzyme hydrolysed methyl p-coumarate (M pCA) 4.5, 9, and 239 times more efficiently than methyl caffeate (MCA), methyl ferulate (MFA) and methyl sinapinate (MSA), respectively. The enzyme was active on substrates containing ferulic acid ester linked to the C-5 and C-2 linkages of arabinofuranose but showed preference for the ester at position 2. 4-Nitrophenyl-2- O- trans-feruloyl-α- l-arabinofuranoside (NPh-5-Fe-Araf) was hydrolysed 100 times more efficiently than 4-nitrophenyl-5- O- trans-feruloyl-α- l-arabinofuranoside (NPh-2-Fe-Araf). Ferulic acid (FA) was efficiently released from destarched wheat bran (DSWB) when the esterase was incubated together with xylanase from Sporotrichum thermophile (a maximum of 92% total ferulic acid released after 4 h incubation). FoFAE-I by itself could release FA but at a level almost five-fold lower than that obtained in the presence of xylanase. The potential of FAE-I for the synthesis of various phenolic acid esters was tested using as a reaction system a surfactantless microemulsions formed in ternary mixture consisting of n-hexane, 1-butanol and water.

Effect of storage on wall-bound phenolics in green asparagus.

The cell walls of green asparagus spears have been analyzed for their phenolic and carbohydrate composition as modified by postharvest storage. Esterified phenolic components were released by sequential alkaline hydrolysis and identified and quantified by diode array HPLC. Significant quantities of ferulic acid (FA) and its derivatives were found to increase at least 3-fold during storage, particularly in walls from the lower parts of the stem, where accompanying changes in sugar composition were also observed. In fresh asparagus, >60% of the total FA was in the form of diferulic acid, and this increased to approximately 70% after 3 days of storage. The main FA dehydrodimers were 8-8-, 8-O-4-, and 8-5-diferulates. These have been detected in other monocotyledonous and dicotyledonous plants, but as a smaller proportion of the total FA. The possible roles phenolic esters might have in relation to the mechanical, textural, and wound-response properties of asparagus spears are discussed.

Effect of laccase and manganese peroxidase on wheat gluten and pentosans during mixing

Wheat gluten and water extractable pentosans (WEP) were mixed in a batch-mixer in the presence of laccase or manganese peroxidase (MnP). The enzymes provoked different changes in mixing behaviour. Doughs were analysed at time to peak ( t) and over two t (2 t or overmixed). The effects of the oxidative enzymes were studied on ferulic acid (FA), arabinoxylans (AX), proteins and possible intermolecular associations in these dough systems. Changes in macromolecular structures were followed using reverse phase-high performance liquid chromatography of phenolic compounds, AX extractability and the viscosity measurements, size exclusion-high performance liquid chromatography and sodium dodecyl sulfate-polyacrylamide gel electrophoresis of proteins. The oxidative enzymes increased dough consistency, accelerated the loss in total FA, decreased AX water extractability and water extractable AX apparent intrinsic viscosity in the dough water extracts. The effects of laccase and MnP were similar on feruloylated AX when compared on a reaction time basis. No covalent complex between AX and protein was detected in mixed and oxidised gluten/WEP.

Effect of Phenolic Structures on the Degradability of Cell Walls Isolated from Newly Extended Apical Internode of Tall Fescue (Festuca arundinacea Schreb.)

Apical internodes of tall fescue (Festuca arundinacea Schreb. var. Clarine) harvested at flowering were sectioned into 5 or 10 equal parts to study in situ degradability and cell wall composition, respectively. The basal (youngest) section had the greatest primary wall content. Cell walls in the upper (older) sections had the highest xylose/arabinose ratio and lignin content and a lignin rich in syringyl units, all typical of extensive secondary wall development. Almost all of the p-coumaric (p-CA) and about half of the ferulic acid (FA) were released by 1 M NaOH and presumed to be ester-linked. The total FA content was approximately double that of p-CA in all sections other than the youngest with a distribution similar to that of total p-CA. However, the ratio of esterified to ether and ether plus ester linked (Et & Et+Es) FA differed with age. Whereas the esterified form remained essentially constant ( approximately 4.5 g/kg of cell wall), Et & Et+Es ferulate increased with increasing age of the tissue and was significantly related to lignin deposition (r = 0.79, P < 0.01). The extent of cell wall degradation after 48 h of incubation in the rumen was inversely related to maturity, falling from 835 g/kg of dry matter in the youngest section to 396 g/kg in the oldest. Both the rate and extent of cell wall degradation were significantly negatively related to the ratio of xylose to arabinose, lignin content, proportion of syringyl units present in lignin, and concentration of Et & Et+Es FA present. A positive relationship between Et & Et+Es FA was also found, with the rate (P < 0.01) being better correlated than the extent (P < 0.05) of cell wall degradation. Application of the newly extended internode model to fescue produced results consistent with the view that both the lignin content and the extent to which lignin was covalently bound to the other wall polymers crucially influenced the rate and extent of degradation.

Changes in the alkaline-labile phenolic compounds of wheat straw cell walls as affected by SO 2 treatment and passage through the gastro-intestine of sheep

Sheep were fed two rations based on untreated (WS) and SO 2-treated (SO 2-WS) wheat straw, and the effect of chemical treatment and passage through the gastro-intestine on the composition and degradation of ester and ether-linked cell wall (CW) phenolics was studied. The SO 2 treatment reduced the content of total ferulic acid (FA) and p-coumaric acid (PCA) by 35% while tripling the level of vanillin and increasing by 40% the concentration of protocatechuic acid. In WS most of the phenolic compounds were CW-bound, but 37% of the vanillic and 88% of the protocatechuic acids were in the alcohol soluble (AS) fraction. The solubilising effect of the treatment was expressed in releasing the phenolics from the CW mainly as AS-lignins. Most of the FA (62%) was ether-linked, whereas most of the PCA (78%) was ester-linked in the CW of WS. The other minor components were either entirely or mostly, etherified units. The SO 2 treatment was more effective in cleaving the ester than the ether bonds of the cinnamic acids. Ester-linked FA was more extensively degraded in the rumen than ester-linked PCA. Ester-linked FA and PCA were more extensively degraded in the rumen than the respective ether-linked compounds. Nevertheless, substantial amounts of ether-linked FA, PCA and other phenolics were removed from CW in the rumen, most likely as oligo-lignols. Phenolic compounds were determined in rumen liquor of sheep fed the WS and WS-SO 2 rations. FA was not detected and PCA was at a very low (20–40 μM) concentration. Phenyl-propanoic acid (PPA) was the major monomeric phenolic compound detected, at concentrations of 580 and 380 μM in the rumen of WS and WS-SO 2 sheep, respectively. It is suggested that hydrogenation of PCA and combined hydrogenation and demethoxylation of FA were responsible for the production of PPA in the rumen.

Distribution and Exudation of Allelochemicals in Wheat Triticum aestivum

Wheat allelopathy has potential for weed suppression. Allelochemicals were identified in wheat seedlings, and they were exuded from seedlings into agar growth medium. p-Hydroxybenzoic, trans-p-coumaric, cis-p-coumaric, syringic, vanillic, trans-ferulic, and cis-ferulic acids and 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA) were identified in both the shoots and roots of 17-day-old wheat seedlings and their associated agar growth medium. Wheat accessions with previously identified allelopathic activity tended to contain higher levels of allelochemicals than poorly allelopathic ones. The allelopathic compounds present in the shoots generally also were identified in the roots and in the agar medium. Allelochemicals were distributed differentially in wheat, with roots normally containing higher levels of allelochemicals than the shoots. When the eight allelochemicals were grouped into benzoic acid and cinnamic acid derivatives, DIMBOA, total coumaric, and total ferulic acids, the amount of each group of allelochemicals was correlated between the roots and the shoots. Most of the allelochemicals identified in the shoots and roots could be exuded by the living roots of wheat seedling into the agar growth medium. However, the amounts of allelochemicals in the agar growth medium were not proportional to those in the roots. Results suggest that wheat plants may retain allelochemicals once synthesized. The presence of allelochemicals in the agar growth medium demonstrated that wheat seedlings were able to synthesize and to exude phytotoxic compounds through their root system that could inhibit the root growth of annual ryegrass.

Ferulic Acid Contents in Mugi Miso (Barley-koji Miso) and Antioxidative Activity of Mugi Koji (Barley-koji)

An investigation of the concentration of total ferulic acid (TFA) and free ferulic acid (FFA) in 23 mugi miso (barley-koji miso) and 10 kome miso (rice-koji miso) was performed using high performance liquid chromatograph (HPLC).Mugi miso and kome misocontained 34.8-163.1 (mean 66.2), μg/g and 13.9-33.2 (mean 25.6), μg/g of TFA and 1.4-29.2 (mean 10.7), μg/g and 1.5-12.7 (mean 6.0), μg/g of FFA, respectively. With proliferation ofmugi koji (barley-koji), the amounts of TFA were decreased from 350μg/g to 198ug/g, however, FFA were increased and reached a maximum (80μg/g) after 30 h of culture. The radical scavenging activity of themugi kojiextract (100μM ascorbic acid) was significantly higher than that of non-inoculated barley extract (25μM) and the longer barleymugi kojicultivated, the period cultivatingmugi kojiwas, the higher the scavenging activity became. The radical scavenging efficacy of ethanolic extract ofmugi kojiseemed to be correlated with the amounts of ferulic acid and the other phenolic compounds.

Barley spent grain: release of hydroxycinnamic acids (ferulic andp-coumaric acids) by commercial enzyme preparations

Barley spent grain is a residue from the brewing process. In this paper, four different commercial enzyme preparations (Viscozyme L, Ultraflo L, Termamyl and Lallzyme) were tested for their ability to release hydroxycinnamic acids, ferulic acid (FA) and p-coumaric acid (PCA), from barley spent grain. The cinnamic acid esterase activities of the enzyme preparations were measured against the model substrate methyl ferulate. Termamyl was the only enzyme preparation that showed no esterase activity. Incubation of Ultraflo L (1.3 U g - 1 substrate, 24 h) with barley spent grain released 70% of the total alkali-extractable FA and 8% of the total alkali-extractable PCA. Under the same conditions, Viscozyme L and Lallzyme released, respectively, 33 and 55% of the total alkali-extractable FA, and 0.8 and 1.6% of the total alkali-extractable PCA. For FA release, enzyme concentrations higher than 1.3U g -1 were saturating. However, for the release of PCA, a continuos increase was observed until 13 U g -1 . The percentages of the FA released by Viscozyme L, Ultraflo L and Lallzyme were higher than those obtained by pure ferulic acid esterases. These three enzyme preparations could be employed for the effective release of hydroxycinnamic acids from barley spent grain.

Determination of Ferulic and p-Coumaric Acids in Wheat Straw and the Amounts Released by Mild Acid and Alkaline Peroxide Treatment

Ferulic acid (FA) and p-coumaric acid (PCA) are two major phenolic acids in a wide variety of graminaceous plants. Particularly, FA has been implicated in cross-linking cell wall polymers. In the present paper, the variations in FA and PCA contents of wheat straw upon various treatments relevant to the process of producing paper-making fibers were investigated. Wheat straw contained 0.48% FA and 0.42% PCA on the basis of dry material. Among them, of the total FA, 56% was esterified only and 44% was etherified. In contrast, >80% of the PCA was esterified only. In general, the phenolic acids had a high tendency to dissolve in hot water or alkaline peroxide solution, as compared to lignin. Nevertheless, the two-step pulping process, a mild acid wash followed by alkaline peroxide bleaching, removed <40% of FA and <20% of PCA. The phenolic acids remaining attached to the lignin might have an effect on the properties of wheat straw fibers made according to this method. Keywords: Ferulic acid; p-coumaric acid; lignin; wheat straw; alkaline peroxide bleaching