Identification and quantification of soluble free, soluble conjugated, and insoluble bound phenolic acids in durum wheat (Triticum turgidum L. var. durum) and derived products by RP-HPLC on a semimicro separation scale

Wild Garlic (Allium ursinum) Preparations in the Design of Novel Functional Pasta

This study investigated the design of novel pasta enriched with different forms of wild garlic (WG): a powder, an extract and an encapsulated extract applied at three enrichment levels (low/middle/high). The effect of cooking on changes in the content of bioactive compounds, antioxidative activity, cooking behaviour, texture, colour and sensory properties of the cooked pasta was evaluated. WG preparations significantly increased the antioxidant potential (by 185-600%) as well as the content of phenolics (by 26-146%), flavonoids (by 40-360%) and potassium (up to three-fold) in the cooked pasta, depending on WG type and enrichment level. Flavonoids were dominantly present in the free form. Cooking resulted in a significant loss of flavonoids (39-75%) whereas phenolics were liberated from the matrix. The highest increase in total phenolics and antioxidant activity was exerted by the WG powder and extract. Pasta hardness and adhesiveness were increased, but encapsulated WG deteriorated cooking behaviour. The best-scored enriched pasta regarding sensory quality and texture was that enriched with WG powder at the low/moderate level.

Antihyaluronidase and Antioxidant Potential of Atriplex sagittata Borkh. in Relation to Phenolic Compounds and Triterpene Saponins

The genus Atriplex provides species that are used as food and natural remedies. In this work, the levels of soluble phenolic acids (free and conjugated) and flavonoids in extracts from roots, stems, leaves and flowers of the unexplored Atriplex sagittata Borkh were investigated by LC-ESI-MS/MS, together with their antioxidant and antihyaluronidase activity. Phenolic acids were present in all parts of A. sagittata; and were most abundant in the leaves (225.24 μg/g dw.), whereas the highest content of flavonoids were found in the flowers (242.71 μg/g dw.). The most common phenolics were 4-hydroxybenzoic and salicylic acids, kaempferol-3-glucoside-7-rhamnoside, kaempferol-3-rutinoside and the rare narcissoside, which was present in almost all morphotic parts. The stem extract had the highest antioxidant activity and total phenolic content (611.86 mg/100 g dw.), whereas flower extract exerted the most potent antihyaluronidase effect (IC₅₀ = 84.67 µg/mL; control-quercetin: IC₅₀ = 514.28 μg/mL). Phytochemical analysis of the flower extract led to the isolation of two triterpene saponins that were shown to be strong hyaluronidase inhibitors (IC₅₀ = 33.77 and 168.15 µg/mL; control-escin: IC₅₀ = 307.38 µg/mL). This is the first report on the presence of phenolics and saponins in A. sagittata. The results suggest that both groups of metabolites may contribute to the overall activity of this plant species.

Antioxidant Capacity and Profiles of Phenolic Acids in Various Genotypes of Purple Wheat

The total phenolic content, phenolic compositions, and antioxidant capacity in the grain of 40 purple wheat genotypes were studied. In this study, purple wheats were investigated in terms of their composition of free and bound phenolic acids and 2,2-diphenyl-1-picrylhydrazyl radical scavenging capacity. The free phenolic content ranged from 164.25 to 271.05 mg GAE/100 g DW and the bound phenolic content was between 182.89-565.62 mg GAE/100 g wheat. The total phenolic content of purple wheat samples ranged from 352.65 to 771.83 mg GAE/100 g wheat. Gallic acid, protocatechuic acid, catechin, 4-hydroxybenzoic acid, syringic acid, ellagic acid, m-coumaric acid, o-coumaric acid, chrysin, caffeic acid, p-coumaric acid, ferulic acid, quercetin, kaempferol, rutin, sinapic acid, and chlorogenic acid were detected by HPLC system. Gallic acid, benzoic acid derivatives, and dominant phenolics, which are frequently found in cereals, were also dominant in purple wheat samples and were found in free fractions. The antioxidant capacity was assessed using the DPPH method. The antioxidant capacity (AA%) in the free phenolic extracts of the purple wheats was between 39.7% and 59.5%, and the AA% values of bound phenolic extract of the purple wheat varied between 42.6% and 62.7%. This study suggested that purple wheat samples have high phenolic compound content as antioxidant potential and therefore consumption of purple wheat-containing food products may provide health benefits.

Development and Optimisation of Solid-Phase Extraction of Extractable and Bound Phenolic Acids in Spelt (Triticum spelta L.) Seeds

A solid-phase extraction (SPE) technique was developed and optimised for isolation and concentration of extractable and bound phenolic acids from germinated spelt seeds, for analysis by liquid chromatography–mass spectrometry. Samples initially underwent solvent extraction under different conditions to maximise the yield of phenolic antioxidants. Optimal extraction conditions for extractable phenolics were absolute methanol as solvent, sample-to-methanol ratio 1:9, and reconstitution in non-acidified water. The bound phenolics were extracted from sample pellets using hydrolysis with 2 M NaOH, acidification of the hydrolysate with formic acid, and simultaneous isolation and purification using Strata X polymeric RP tubes. Compared to liquid-liquid extraction, this direct SPE protocol has significant advantages in terms of higher extraction efficiencies of total and individual phenolics and their antioxidant activities. These data suggest that direct SPE represents a rapid and reliable method for quantitative analysis of both the extractable and the commonly overlooked bound phenolics in Triticum spelta seeds.

Studies on the Impact of Malting and Mashing on the Free, Soluble Ester-Bound, and Insoluble Ester-Bound Forms of Desired and Undesired Phenolic Acids Aiming at Styrene Mitigation during Wheat Beer Brewing

Mitigation studies on styrene in wheat beer found no correlation between the free phenolic acid contents in the processing steps and the final concentrations of the toxicologically relevant styrene and the desired aroma-active vinyl aromatics in beer, which can be explained by the presence of phenolic acid releasing enzymes that are still active after kiln-drying and by the yeast's own feruloyl esterase activity. The present study contributed to a better understanding of the coherence between the free, soluble ester-bound, and insoluble ester-bound forms of cinnamic, p-coumaric, and ferulic acid during malting and mashing of barley and wheat varieties. Concentration differences in malt by factors of up to 1700 were found between the total cinnamic acid contents (an undesired precursor of the toxicologically relevant styrene) and the total contents of p-coumaric and ferulic acid (both desired precursors of the aroma-active compounds 4-vinylphenol and 2-methoxy-4-vinylphenol). In grain and malt, cinnamic acid occurred predominantly in a soluble form, whereas the desired precursors were mainly insoluble ester-bound. This had a direct effect on the transfer rates from malt into wort, which were found to be >100% for cinnamic acid, revealing that a complete transfer was accompanied by an additional biosynthesis, but only <8% for the desired phenolic acids. Interestingly, in the wort, cinnamic and p-coumaric acid contents were dominated by the free form, while ferulic acid was mostly still soluble ester-bound. Overall, the use of barley malts led to an introduction of cinnamic, p-coumaric, and ferulic acid into the wort in a ratio of 2:14:84, and the use of wheat malt in a ratio of 1:2:97.

Distribution of free and bound phenolic compounds, and alkylresorcinols in wheat aleurone enriched fractions

Several companies have focused their attention on the development of technologies able to enrich/isolate the wheat aleuronic layer because it is a source of bioactive compounds. In this work two different wheat bran fractions enriched in aleurone (AF1, 55-70% aleurone and AF2, 75-90% aleurone) were obtained by a dry fractionation based on air classification. Free and bound phenolic compounds, and alkylresorcinols were determined in the two fractions by HPLC-DAD-ESI-TOF-MS and GC-MS, respectively. To our knowledge, feruloyl di-hexoside was described for the first time in wheat aleurone and flavonoids were quantified for the first time in this fraction. The results have shown that the most concentrated free phenolic compounds were flavonoids, and AF1 was the fraction that presented the highest flavonoid content; whereas trans ferulic acid was the most abundant bound phenolic acid, which highest content was obtained in AF2. Besides, total content of ferulic acid monomers in AF2 was 33.63% higher than in AF1, whereas total content of ferulic acid dimers/trimers in AF1 was 33.9% higher than in AF2. The highest content of alkylresorcinols was obtained in AF1 and it was 10.30% higher than the obtained in AF2. Therefore, it can be stated that this green technology could be used to produce enriched aleurone fractions as source of phenolic and alkylresorcinol compounds. These fractions could be of great interest for the formulation of enriched foods.

Elevated CO2 Impact on Common Wheat (Triticum aestivum L.) Yield, Wholemeal Quality, and Sanitary Risk

The rising atmospheric CO_2, concentration is expected to exert a strong impact on crop production, enhancing crop growth but threatening food security and safety. An improver wheat, a hybrid, and its parents were grown at elevated CO_2, e[CO₂] in open field, and their yield and rheological, nutritional, and sanitary quality were assessed. For all cultivars, grain yield increased (+16%) and protein content decreased (-7%), accompanied by a reduction in dough strength. Grain nitrogen yield increased (+24%) only in ordinary bread making cultivars. e[CO₂] did not result in significant changes in phenolic acid content and composition, whereas it produced a significant increase in the deoxynivalenol content. Different responses to e[CO₂] between cultivars were found for yield parameters, while the effect on qualitative traits was quite similar. In the upcoming wheat cropping systems, agronomic practices and cultivar selection suited to guarantee higher nitrogen responsiveness and minimization of sanitary risk are required.

Bioactive compounds, nutritional benefits and food applications of colored wheat: a comprehensive review

The consumers' demands have changed from energy providing diet to a diet with a balanced nutrient profile along with metabolic, physiological and functional health benefits. They are seeking colorants derived from natural sources to enhance the nutritional and antioxidant value of foods. Colored wheat (Triticum aestivum) contains many phytochemicals, responsible for numerous health benefits. Colored wheat (blue, black, purple and red) contains a good amount of anthocyanins and carotenoids that are primarily located in the outer aleurone layer. Food regulatory and safety authorities and food processing industries are trying to minimize the usage of synthetic food colorants and dyes. Colored wheat is imperative for food processing industries as high-value pigments present in the bran layer (milling industry co-product) can easily be extracted and utilized as functional foods and natural colorants. The extracted pigments such as anthocyanin can replace synthetic dyes currently used in food, drug and cosmetics. Additionally, natural additives improve the nutritional value, appearance, texture, flavor, and storage properties of food products. This review presents a brief knowledge of the nutritional composition of colored wheat including phytochemicals and bioactive compounds like flavonoids, phenolic compounds, their health benefits, methods and technologies used for processing and extraction as well as the effects of processing on these compounds.

Assessment of phytochemical compounds in functional couscous: Determination of free and bound phenols and alkylresorcinols

The aim of this study was to evaluate the content of free and bound phenols and alkylresorcinols in functional couscous enriched with barley coarse fraction obtained by air classification. Two different levels of enriched barley flour (20 and 30%) were used for the formulation of couscous and they were compared with a control couscous made with 100% of semolina. HPLC-ESI-TOF-MS was used to determine the phenolic composition in couscous samples. Total free phenolic compounds content in control couscous was 182 μg/100 g d.m. This amount increases significantly when coarse barley flour is added reaching value of 2273 μg/100 g d.m. and 2978 μg/100 g d.m. when 20 and 30% of barley coarse fraction was used, respectively. Moreover, the main free phenolic compounds in enriched barley samples are represented by flavan-3-ols. Bound phenols ranged from 5242 μg/100 g d.m. for control couscous to 27,092 μg/100 g d.m. for couscous with 30% of barley coarse fraction with a strong prevalence of phenolic acids. Finally, regarding alkylresorcinol compounds, they ranged from 1.01 mg/g d.m. for control couscous to 2.46 mg/g d.m. for couscous with 30% of barley coarse fraction. In conclusion, on the basis of obtained results, barley coarse fraction can be considered a good ingredient to develop functional couscous naturally enriched of phenolic compounds and alkylresorcinols.

Effect of In Vitro Digestion on Phytochemical Profiles and Cellular Antioxidant Activity of Whole Grains

Most of the previous in vitro digestion treatments were conducted directly to whole grains without extraction of free phenolics, thus the bioaccessible phenolics contained both free phenolics that survived the digestion and digested phenolics released by digestion. However, the profiles of digested phenolics released by digestion remain unknown. This study was designed to investigate the phytochemical contents, peroxyl radical scavenging capacities (PSCs), and cellular antioxidant activities (CAAs) of free, digested, and bound fractions of whole grains. Total phenolic contents of whole grains were highest in digested fraction, followed by free and bound fractions. The predominant phenolics were 12 phenolic acids and one flavonoid, which mostly existed in bound forms, then in digested and free forms. The digested phenolics bound to proteins were in conjugated form. The bound fractions had the highest PSCs, followed by free and digested fractions. CAAs were highest in bound fractions, followed by digested and free fractions.

Determination of Free Soluble Phenolic Compounds in Grains of Ancient Wheat Varieties ( Triticum sp. pl.) by Liquid Chromatography-Tandem Mass Spectrometry

A method of liquid chromatography coupled with tandem mass spectrometry was developed and validated for the determination of free soluble phenolic compounds in eight ancient varieties of wheat ( Triticum sp. pl.): Autonomia, Gentil rosso, Inallettabile, Leone aristato, Mentana, Poulard di Ciano, Risciola, and Terminillo. Trace compounds such as two conjugated flavones, vitexin (17.13-34.32 μg/kg) and isovitexin (9.76-30.01 μg/kg), were also determined. Poulard di Ciano, presumably an autochthonous wheat of the Reggio Emilia province (northern Italy), showed a peculiar quali/quantitative phenolic profile (7097.03 μg/kg sum of total phenolic compounds and 1.97 sum of hydroxycinnamic acids to sum of hydroxybenzoic acids ratio) along with a tetraploid genome. Terminillo, Risciola, Gentil rosso, Mentana, and Leone aristato showed hexaploid genomes and high concentrations of phenolic compounds (ranging from 6796.12 to 7605.78 μg/kg), also in comparison with two modern varieties of bread wheat, Bolero and Blasco. The targeted metabolomic approach proved to be effective to determine some secondary metabolites of wheat. The richness in phenolic compounds combined with high rusticity and adaptability to marginal soils showed by ancient wheat varieties make them suitable for sustainable agricultural and organic cultivation.

Determination of phenolic compounds in ancient and modern durum wheat genotypes

Due to its significant amount of antioxidants, durum wheat (Triticum turgidum ssp. durum) could potentially contribute to the protection against a number of chronic diseases, such as diabetes, cardiovascular disease, and cancer. The increasing interest toward healthy food among both consumers and scientists has moved the focus toward the phytochemical content of whole wheat grains. The aim of this study was to identify the phytochemical composition of 22 cultivars belonging to old and modern durum wheat genotypes, including antioxidant capacity (DPPH and FRAP tests). In addition, five phenolic acids involved in the vanillin biosynthesis pathway and in the defence mechanism of plants were screened using UHPLC-MS/MS. Remarkable quantitative differences in the amount of the five phenolic acids analysed (p < 0.05) were detected among the wheat genotypes investigated. Results showed that among the investigated phenolic compounds, trans-ferulic acid was the most abundant, ranging from 13.28 to 324.69 μg/g; all the other identified compounds were present at lower concentrations. Moreover, significant differences on the antioxidant activity were observed. Collected data suggested possible differences between biosynthetic pathway of secondary metabolites among durum wheat genotypes.

Sustainable Electrochemical Depolymerization of Lignin in Reusable Ionic Liquids

Lignin's aromatic building blocks provide a chemical resource that is, in theory, ideal for substitution of aromatic petrochemicals. Moreover, degradation and valorization of lignin has the potential to generate many high-value chemicals for technical applications. In this study, electrochemical degradation of alkali and Organosolv lignin was performed using the ionic liquids 1-ethyl-3-methylimidazolium trifluoromethanesulfonate and triethylammonium methanesulfonate. The extensive degradation of the investigated lignins with simultaneous almost full recovery of the electrolyte materials provided a sustainable alternative to more common lignin degradation processes. We demonstrate here that both the presence (and the absence) of water during electrolysis and proton transport reactions had significant impact on the degradation efficiency. Hydrogen peroxide radical formation promoted certain electrochemical mechanisms in electrolyte systems "contaminated" with water and increased yields of low molecular weight products significantly. The proposed mechanisms were tentatively confirmed by determining product distributions using a combination of liquid chromatography-mass spectrometry and gas-chromatography-mass spectrometry, allowing measurement of both polar versus non-polar as well as volatile versus non-volatile components in the mixtures.

Binary Solvent Extraction of Tocols, γ-Oryzanol, and Ferulic Acid from Rice Bran Using Alkaline Treatment Combined with Ultrasonication

Alkaline treatment (Alk) combined with ultrasound-assisted extraction (UAE) (Alk+UAE) was examined as a means of extracting tocols and γ-oryzanol from rice bran into an organic phase while simultaneously recovering ferulic acid into an aqueous phase. The tocols and γ-oryzanol/ferulic acid yields were determined using high-performance liquid chromatography with fluorescence and UV detection. The effects of extraction conditions were evaluated by varying the Alk treatment temperature and extraction duration. The maximum yields of tocols and γ-oryzanol were obtained at 25 °C over a time span of 30 min. When the temperature was increased to 80 °C, the yield of ferulic acid increased dramatically, whereas the recovery of γ-oryzanol slightly decreased. Employing the Alk+UAE procedure, the recovered concentrations of tocols, γ-oryzanol, and ferulic acid were in the ranges of 146-518, 1591-3629, and 352-970 μg/g, respectively. These results are in good agreement with those reported for rice bran samples from Thailand.

From seed to cooked pasta: influence of traditional and non-conventional transformation processes on total antioxidant capacity and phenolic acid content

The aim of this work was to compare the traditional with a non-conventional (i.e. kernel micronisation) durum wheat milling process by monitoring the content of bound, conjugated and free phenolic acids (PAs) and the level of the total antioxidant capacity (TAC) occurring in the durum wheat pasta production chain, from seed to cooked pasta. The traditional transformation processes negatively influenced TAC and PA content (40% and 89% decrease from seed to cooked pasta, respectively), mainly during the milling process (25% and 84% decrease of TAC and PA, respectively), which has been related to the removal of external layers of kernels. Conversely, the micronisation applied on durum wheat kernels allowed to obtain whole-wheat pasta that preserved the seed endowment of antioxidant compounds even in cooked pasta. These results indicate the micronisation as a valuable approach to produce pasta with improved nutritional value and potential health-promoting effects compared to the traditional pasta.

Use of bran fractions and debranned kernels for the development of pasta with high nutritional and healthy potential

The quality of pasta produced with debranning products (bran fractions, BF, and debranned kernels, DK) of durum wheat was investigated by evaluating their total antioxidant capacity, occurrence of nutritional and bioactive compounds, and sensory properties. Two pasta samples, produced with BF-enriched semolina (BF pasta) or only with micronized DK (DK pasta), respectively, were compared with pasta made with traditional semolina (control pasta). BF pasta and DK pasta displayed significantly higher content of bioactive compounds, such as phenolic compounds and dietary fibre, than control pasta, to a different extent for the diverse compounds. The present study indicates that the debranning process allows to produce pasta with a high content of healthy compounds and minimal effects on sensory properties, using only the natural endowment of durum wheat. This approach is suitable to produce cereal-based foods with the potential nutritional and health benefits of partially refined cereals and limitation of their main drawbacks.

Comparative Analysis of Phenolic Compound Characterization and Their Biosynthesis Genes between Two Diverse Bread Wheat (Triticum aestivum) Varieties Differing for Chapatti (Unleavened Flat Bread) Quality

Phenolic compounds (PCs) affect the bread quality and can also affect the other types of end-use food products such as chapatti (unleavened flat bread), now globally recognized wheat-based food product. The detailed analysis of PCs and their biosynthesis genes in diverse bread wheat (Triticum aestivum) varieties differing for chapatti quality have not been studied. In this study, the identification and quantification of PCs using UPLC-QTOF-MS and/or MS/MS and functional genomics techniques such as microarrays and qRT-PCR of their biosynthesis genes have been studied in a good chapatti variety, "C 306" and a poor chapatti variety, "Sonalika." About 80% (69/87) of plant phenolic compounds were tentatively identified in these varieties. Nine PCs (hinokinin, coutaric acid, fertaric acid, p-coumaroylqunic acid, kaempferide, isorhamnetin, epigallocatechin gallate, methyl isoorientin-2'-O-rhamnoside, and cyanidin-3-rutinoside) were identified only in the good chapatti variety and four PCs (tricin, apigenindin, quercetin-3-O-glucuronide, and myricetin-3-glucoside) in the poor chapatti variety. Therefore, about 20% of the identified PCs are unique to each other and may be "variety or genotype" specific PCs. Fourteen PCs used for quantification showed high variation between the varieties. The microarray data of 44 phenolic compound biosynthesis genes and 17 of them on qRT-PCR showed variation in expression level during seed development and majority of them showed low expression in the good chapatti variety. The expression pattern in the good chapatti variety was largely in agreement with that of phenolic compounds. The level of variation of 12 genes was high between the good and poor chapatti quality varieties and has potential in development of markers. The information generated in this study can be extended onto a larger germplasm set for development of molecular markers using QTL and/or association mapping approaches for their application in wheat breeding.

Performance of broiler chickens offered nutritionally-equivalent diets based on two red grain sorghums with quantified kafirin concentrations as intact pellets or re-ground mash following steam-pelleting at 65 or 97°C conditioning temperatures

The Liverpool Plains is a fertile agricultural region in New South Wales, Australia. Two sorghums from the 2009 Liverpool Plains harvest, sorghums #3 and #5, were extensively characterised which included concentrations of kafirin and phenolic compounds plus rapid visco-analysis (RVA) starch pasting profiles. Diets based on these two sorghums were formulated to be iso-nitrogenous and iso-energetic and were offered to male Ross 308 broiler chicks from 7 to 28 days post--hatch as either intact pellets or reground mash following steam-pelleting at conditioning temperatures of either 65 or 97°C. Thus the feeding study consisted of a 2 × 2 × 2 factorial array of dietary treatments: two sorghum varieties, two feed forms and two conditioning temperatures. Each of the eight treatments was replicated six times with six birds per replicate cage. Assessed parameters included growth performance, nutrient utilisation, apparent starch and protein (N) digestibility coefficients and disappearance rates from the distal jejunum and distal ileum. Intact pellets supported higher (P < 0.001) feed intakes and weight gains by 9.83 and 9.08%, respectively, than reground mash diets. Feed conversion ratios of broilers offered diets steam-conditioned at 97°C were 2.46% inferior (P < 0.001) in comparison to 65°C diets and both apparent metabolizable energy (AME) and N-corrected AME (AMEn) were compromised. Broilers offered sorghum #3-based diets significantly (P < 0.001) outperformed their sorghum #5 counterparts in terms of weight gain by 3.75% (1,334 versus 1,223 g/bird), FCR by 4.81% (1.524 versus 1.601), AME by 1.06 MJ (13.61 versus 12.55 MJ/kg), ME:GE ratio (ME:GE) by 4.81% (0.806 versus 0.769) and AMEn by 1.03 MJ (12.38 versus 11.35 MJ/kg). The inferiority of sorghum #5 appeared to be associated with higher concentrations of kafirin (61.5 versus 50.7 g/kg) and conjugated phenolic acids, including ferulic acid (31.1 versus 25.6 µg/g). There were no significant differences in jejunal and ileal starch and protein (N) digestibility coefficients between the two sorghums. However, starch to protein (N) disappearance rate ratios from the distal jejunum were significantly (P < 0.001) correlated with ME:GE and AME. The multiple linear regression equations indicated that energy utilisation was enhanced by coupling rapidly digestible protein with slowly digestible starch, which suggests that bilateral bioavailability of starch and protein is pivotal to efficient energy utilisation.