Individual Phenolic Compounds Research Articles

Grumixama (Eugenia brasiliensis Lamarck) functional phytochemicals: Effect of environmental conditions and ripening process

Grumixama (Eugenia brasiliensis Lamarck) is a native fruit of the Atlantic rain forest that belongs to Myrtaceae family. It presents economic potential due to the attractive sensory attributes and bioactive compounds. This study determined physicochemical characteristics, minerals (K, Na, Ca, Mg, Mn), sugars (fructose, glucose, sucrose), total content of phenolics, proanthocyanidins, and anthocyanins, individual phenolic compounds, and antioxidant capacity at three ripening stages of grumixama from two growing locations (Florianópolis and São Ludgero, Santa Catarina state, Brazil). Of the 23 phenolic compounds quantified, gallic acid, ellagic acid, quercetin, and isoquercetrin were the major (with values up to 69.08 mg/100 g fresh weight). Fructose (up to 5.28 g/100 g fresh weight) was the main sugar, and K (up to 589.30 mg/100 g fresh weight) was the major mineral, followed by Ca, Na, and Mg (up to 149.02, 117.52, and 80.18 mg/100 g fresh weight, respectively). More mature fruits had the highest levels of total phenolics (up to 469.18 mg gallic acid equivalent/100 g fresh weight), anthocyanins (up to 518.64 mg cyanidin 3-glucoside equivalent/100 g fresh weight), and proanthocyanidins (up to 420.70 mg catechin equivalent/100 g fresh weight). The influence of growing location and ripening on nutritional and physicochemical characteristics was confirmed. There was a statistically significant interaction (p < 0.05) between both factors for almost all parameters evaluated. The results showed that grumixama fruits could contribute to the daily intake of nutritional and bioactive compounds for consumers' health.

Castor Bean (Ricinus communis L.) Polyphenolic Extracts Exhibited Anti-inflammatory Effects on LPS-Stimulated RAW 264.7 Macrophages

ObjectivesThis research aimed to explore the anti-inflammatory properties of two different aqueous extracts from Mexican Castor bean leaves accessions (R1 and R2) in lipopolysaccharide (LPS)-challenged murine RAW 264.7 cells. MethodsTwo leaves accessions (S1 and S2) grown in Amazcala (Mexico) were washed, sun-dried (35–60 °C), ground, and screened (250 mm particle size). Aqueous extracts were prepared by dissolving 100 mg of the powders in 10 mL distilled water and maintained in a water bath (40 °C) under stirring for 1 h. Samples were then centrifuged (3500 g, 15 min, 4 °C). Total phenolics (TP), total flavonoids (TF), condensed tannins (CT), and antioxidant capacity measurements (ABTS and DPPH) were quantified spectrophotometrically. Individual phenolics were quantified by HPLC-DAD, and metabolomic analysis from gas chromatography (GC)-MS was conducted using MetaboAnalyst. The extracts were assayed against LPS-induced RAW 264.7 cells, whereas cell viability (MTT) and nitric oxide (Griess reaction) measurements were carried out. ResultsThe total polyphenolic composition of the extracts showed no differences (P < 0.05) on their TF and CT composition, but S2 displayed a higher TF content than S1. Identifying individual phenolic compounds by HPLC-DAD highlighted ellagic and gallic acids (17.13–28.77 mg/g dry weight) as the primary phenolic acids, whereas S2 showed the highest abundance of (+)-catechin. S1 was the extract with the highest DPPH antioxidant capacity (P < 0.05) (80.17%). None of the extracts was cytotoxic at the evaluated concentrations (10–50% v/v), but S2 was more effective in inhibiting nitric oxide production (44.94%). ConclusionsThe extracts showed anti-inflammatory potential by inhibiting NO production and could be used to manufacture bioactive compounds-rich food-grade-based ingredients. However, as ricinine, a toxic protein, has been reported in the leaves, methods eliminating ricinine from the extracts are required for safely using the extracts. Funding SourcesThe authors acknowledge “Fondos para el Desarrollo del Conocimiento (FONDEC) from Universidad Autónoma de Querétaro (UAQ) 8289, Registry SVSU-DV-2021–09) for the provided resources.

A novel bicyclic lactone and other polyphenols from the commercially important vegetable Anthriscus cerefolium

Garden chervil, Anthriscus cerefolium (L.) Hoffm. is an important herb commonly applied in Norwegian large-scale commercial kitchens. This species is a highly enriched source of phenolics, containing 1260 mg gallic acid equivalents (GAE) 100–1 g DM, however, the individual phenolic compounds have been scarcely characterized. Here we report on the qualitative and quantitative content of phenolics in garden chervil. The structure of the main phenolic compound was elucidated to be the previously undescribed compound 1,3-dicaffeoyl-5-malonyl-δ-quinide (1) by means of 1D- and 2D NMR and high-resolution mass spectrometry. The known flavones apigenin 7-O-β-(2″-apiofuranosylglucopyranoside) (= apiin) (2), apigenin 7-(2″-apiosyl-6″-malonylglucoside) (3) and luteolin 7-glucoside (4) were also identified. Compound 3 is reported for the first time from this plant species. The main phenolic compound, 1,3-dicaffeoyl-5-malonyl-δ-quinide, exhibited moderate cytotoxicity towards acute monocytic leukaemia cells (MOLM-13) and rat kidney epithelial cells (NRK) with EC50 between 400 and 600 µM.

Determination of Biochemical Characteristics, Antioxidant Activities, and Individual Phenolic Compounds of 13 Native Turkish Grape Juices

Determination of Biochemical Characteristics, Antioxidant Activities, and Individual Phenolic Compounds of 13 Native Turkish Grape Juices

Impact of vacuum drying on drying characteristics and functional properties of beetroot (Beta vulgaris)

Beetroot has been considered as an attractive raw material to dehydrate owing to possessing valuable essential nutrients. In the present work, it was appraised whether vacuum drying (VD) could be a proper alternative to freeze-drying (FD). Hence, the impact of both drying techniques on the physicochemical properties, betalainic pigments, antioxidant potential and individual phenolic compounds of beetroot was studied. Vacuum drying kinetics for obtaining the predominant drying rate period of beetroot was also evaluated. Results showed that the increase of temperature conducive to an increase of drying rate and effectively shorten drying time. In general, VD samples retained the proximate composition content of beetroot better than FD. FD and VD samples led to a better conservation of betacyanin content and antioxidant capacity (DPPH) at 50 and 80°C, respectively. Nevertheless, VD (50°C) stands out above FD in the Total Polyphenol Content (TPC) and the Oxygen Radical Absorbance Capacity (ORAC) values. In addition, the syringic acid appears identified and quantified in VD samples at 50°C but not in FD samples. In consequence, this work shows that for vacuum dried beetroot, 50°C can be a suitable drying temperature in replacement of freeze-drying.

Chemical Composition, Antioxidant and Anti-Enzymatic Activity of Golden Root (Rhodiola rosea L.) Commercial Samples

The aim of the study was to compare the chemical composition of the water and hydromethanolic extracts of R. rosea commercial samples in relation to their biological activity. For this purpose, the HPLC method was used for the determination of eleven phenolic compounds and AAS/AES was used for determination of five essential elements. Moreover, the contents of total phenolic, total flavonoid, total phenolic acids, and L(+)-ascorbic acid were determined. The antioxidant activity was assessed by DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS radical scavenging activity, ferric-reducing/antioxidant power (FRAP), and cupric-reducing antioxidant capacity (CUPRAC) assays, while the inhibitory activity against AChE and BChE enzymes was determined using Ellman’s method. The results showed that the hydromethanolic extracts of R. rosea were richer in phenolic compounds and showed higher antioxidant and neurobiological activity than the water extracts. However, the water extracts gave higher contents of determined elements. Among the individual phenolic compounds gallic acid (2.33 mg/g DW) and sinapic acid (386.44 µg/g DW) had the highest concentrations in the hydromethanolic and water extracts, respectively. Moreover, the most extracts were observed to be more efficient on BChE. Moreover, the correlation analysis indicated a high positive relationship between chemical composition and biological activity in both extracts of R. rosea.

The effect of different drying methods on total bioactive properties, individual phenolic compounds, rehydration ability, color, and microstructural characteristics of Asian pear

This study aimed to investigate the effects of FD (freeze drying), USVD (ultrasound-assisted vacuum drying), HAD (hot air drying). and IRD (infrared drying) methods on drying behavior, total phenolic antioxidant activity, individual phenolic distribution, rehydration capacity, Scanning Electron Microscopy image, and color quality of Asian pear. HAD showed the longest drying period with 420 min and followed by USVD with 345 and IRD with 240 min. The method difference had a significant effect on the total phenolic and antioxidant activity values of the samples (p < 0.05). The TPC, DPPH, and CUPRAC value were found as 111.59–316.40 mg/100 g GAE, 336.94–559.41 mg/100 g TE, and 161.00–859.73 mg/100 g TE, respectively. Samples dried with FD showed the highest TPC and AA values, followed by USVD, IRD, and HAD. The effect of drying techniques on the distribution of phenolic compounds was found to be significant (p < 0.05). HAD and the IRD process caused a decrease in the amount of all identified phenolic compounds. While USVD caused an increase in the amount of Chlorogenic acid, FD did not cause a significant change. Higher HMF results were found in samples dried via IRD followed by HAD. While the porous structure was preserved in the samples dried with FD and USVD, the porosity structure of the samples dried with HAD and IRD completely disappeared. FD and HAD showed the highest and lowest rehydration capacity, respectively. FD and USVD showed lower color change than IRD and HAD. The results of this study showed that USVD and FD can be used as an alternative method to HAD in drying Asian pear. Practical Application Pear fruit is one of the most consumed fruits worldwide. Pear fruit is very sensitive to microbial and enzymatic degradation due to its high sugar, bioactive component, and moisture content. To increase the shelf life of the pear fruit and to ensure consumption throughout the year, it must be subjected to a preservation technique. Drying is one of the main methods used to extend the long shelf life of fruits and vegetables. Undesirable changes may occur in the quality characteristics of fruits during drying. Therefore, determining the appropriate drying method is vital for the quality of the final product. In this study, the effects of different drying methods on many quality characteristics of pear fruit were investigated. This study has the potential to provide a new perspective on the drying of pear fruit.

Green and highly extraction of phenolic compounds and antioxidant capacity from kinkeliba (Combretum micranthum G. Don) by natural deep eutectic solvents (NADESs) using maceration, ultrasound-assisted extraction and homogenate-assisted extraction

Kinkeliba (C. micranthum) is a tropical plant widely used for its tremendous phytochemicals and biological activities. In the present study, three green carboxylic acid-based natural deep eutectic solvents (NADESs) were used to assess the extraction of phenolic compounds in terms of total phenolic content (TPC), total flavonoid content (TFC), individual phenolic compounds and antioxidant capacity (DPPH and FRAP assays) from dried C. micranthum leaves. For the synthesis of NADESs choline chloride was used as hydrogen bond acceptors (HBA) in combination with lactic acid (ChLa), acetic acid (ChAa) and tartaric acid (ChTa) as hydrogen bond donors (HBDs). The conventional solvents including distilled water, pure methanol and pure ethanol were used for comparison. Three extraction methods including maceration extraction (ME), homogenate-assisted extraction (HAE) and ultrasound-assisted extraction (UAE) were tested to determine the best extraction conditions. The solvents combined with the extraction methods were successfully applied for the recovery of phenolic compounds from C. micranthum leaves. ChLa exhibited the highest performance giving the TPC (21.12 ± 0.13–23.62 ± 0.58 mg GAE/g, followed by ChAc (15.49 ± 0.13–18.85 ± 0.39 mg GAE/g), water (17.08 ± 0.32–18.13 ± 0.13 mg GAE/g), ChTa (14.49 ± 0.26–17.44 ± 0.19 mg GAE/g), methanol (7.46 ± 0.45–11.64 ± 0.32 mg GAE/g) and ethanol (2.88 ± 0.39–4.60 ± 0.39 mg GAE/g), respectively. For TFC, ChLa (4.38 ± 0.09–5.01 ± 0.09 mg ECE/g) was the most prominent solvent, followed by ChAc (2.84 ± 0.04–5.01 ± 0.36 mg ECE/g), methanol (1.93 ± 053–4.85 ± 0.04 mg ECE/g), ethanol (1.49 ± 0.36–4.16 ± 0.04 mg ECE/g), ChTa (1.09 ± 0.04–3.22 ± 0.13 mg ECE/g) and water (1.15 ± 0.04–1.37 ± 0.44 mg ECE/g), respectively. The acidic NADESs especially ChLa and ChAa exhibited the best efficiencies compared to the conventional solvents. Furthermore, UAE and HAE provided good extraction efficiency in a short extraction time (30 min) in terms of the TPC, TFC, individual phenolic compounds and the antioxidant capacity compared to ME which gave a similar yield with 12 h of extraction time. Principal component analysis (PCA) showed that C. micranthum extracts could clearly be discriminated in terms of phytochemical compounds and antioxidant capacity and UAE, HAE or ME combined with ChLa ChAc or ChTa were the best choices to higher extraction efficiency.

Determination of Cabernet Sauvignon wine quality parameters in Chile by Absorbance-Transmission and fluorescence Excitation Emission Matrix (A-TEEM) spectroscopy

A-TEEM spectroscopy is presented as a novel rapid quantitative analysis method for 44 individual phenolic and basic wine chemistry compounds. To date no practical and combined analysis method for these recognized quality parameters important to the wine industry exists. The method was implemented in a Lambert-Beer linear concentration range to facilitate traceable absorbance and fluorescence spectral signatures. Both components were comparatively analyzed as single- and combined multi-block variable sets, and regressed against HPLC–DAD, UV–vis spectroscopy and other analytical reference data, using the Extreme Gradient Boost Regression (XGBR) and Partial Least Squares Regression (PLSR) algorithms. The approach was applied on 126 wines, and subsequently validated by a random split of 13% of the set and an additional independent set of 16 wines. XGBR with multi-block data organization systematically yielded the highest prediction accuracy and precision with respective overall valid fits indicated by mean R2 and relative bias of 0.94 ± 0.04 and 4.1 ± 1.8%.

Quantification of Amino Acids, Phenolic Compounds Profiling from Nine Rice Varieties and Their Antioxidant Potential.

In recent years, the health benefits of the pigmented rice varieties have been reported due to the richness of their bioactive compounds. Therefore, this study evaluated the antioxidant, total flavonoid, total phenolic, anthocyanin content, amino acid and individual phenolic compound quantification of nine Korean-grown rice varieties using spectrophotometric, HPLC-FLD-MS/MS and UHPLC Q-TOF-MS/MS methods. Our research found that the free fractions of DM29 (red rice) had the highest free radical scavenging ability of ABTS and DPPH. In contrast, the highest ferric reducing antioxidant power was observed in the 01708 brown rice variety. The majority of phenolic compounds such as quercetin, ferulic acid, p-coumaric acid, ascorbic acid, caffeic acid and genistein were found in the DM29 sample. The phenolic content of rice varies depending on its color, with DM29 red rice having the highest TPC, TFC and TAC levels. At the same time, the presence of the majority of amino acids was quantified in the 01708 and GR (Gangwon) brown rice varieties. According to this study, colored rice varieties are high in amino acids, phenolic compounds and antioxidants. This research would be beneficial in furthering our understanding of the nutritional value of different colors of rice and their high potential as a natural antioxidant.

How steaming and drying processes affect the active compounds and antioxidant types of Gastrodia elata Bl. f. glauca S. chow

As both a traditional medicine and food material, fresh Gastrodia elata requires a curing process for quality improvement. The effects of steaming and various drying methods (sun-, hot-air-, microwave-vacuum-, freeze- and vacuum-drying) on the total phenolic, total flavonoid, ascorbic acid, adenosine, and phenolic compound contents, antioxidant activities (scavenging DPPH•, ABTS+•, OH• and reducing power) and microstructures were investigated in this study. The contents of adenosine and individual phenolic compounds were analyzed using high-performance liquid chromatography. The results showed that steaming had adverse effects on the total phenolic, total flavonoid, adenosine, parishin C, vanillyl alcohol, quercetin and cinnamic acid contents, while subsequent hot-air- and freeze-drying showed compensatory effects. Steaming significantly increased the levels of gastrodin, p-hydroxybenzylalcohol, p-hydroxybenzaldehyde, parishins (A, B and E) and catechin (by 3.4-, 1.1-, 1.1-, 3.8-, 6-, 1.4- and 1.5-fold, respectively, p < 0.05) compared to the fresh samples, which were further increased by hot-air- and freeze-drying. Hot-air- and freeze-drying significantly increased the levels of adenosine, gastrodin, p-hydroxybenzylalcohol, p-hydroxybenzaldehyde, parishins (A, B and C), vanillyl alcohol, catechin, caffeic acid, quercetin and cinnamic acid by 1.1–11.6-fold (p < 0.05) compared to steaming treatment. Steaming reduced all the antioxidant activities, which were restored partially by hot-air- and freeze-drying. Principal component and clustering analyses revealed the relationship among the samples, phenolics, and antioxidant activities, which suggested a steaming-then-drying action mechanism in which steaming changes enzymes and starch hydrolysis and drying promote condensation reactions. Collectively, steaming-then-hot-air- or freeze-drying is a promising method for enhancing the quality of Gastrodia elata for food applications.

Fractionation of foam-mat dried rice bean hydrolysates using membrane filtration and solid phase extraction: Peptide- and phenolic-based fractions with bioactive potential

Flavourzyme was used to hydrolyze the germinated rice bean, and the hydrolysates were separated using membrane ultrafiltration with a molecular weight (MW) cut-off of 3 kDa. The ultrafiltration permeate fraction (UFP), non-fractionated hydrolysate (RH), and ultrafiltration retentate fraction (UFR) were foam-mat dried at two temperatures, 60 and 70 °C. The content of each phenolic composition in dried RH samples decreased with increasing drying temperature particularly gallic acid, p-coumaric acid, vanillin, rutin, and, quercetin dropped by 27, 24, 21, 35 and 33%, however the kind of phenolic compositions identified in dried samples was unaffected by drying temperature. Dried UFR and dried UFP had different chromatograms. When the dried UFP and dried UFR chromatograms were examined, it was discovered that the intensity of the peaks in the dried UFR chromatogram was much lower. The majority of phenolics can pass through ultrafiltration membranes with a molecular weight cut-off of 3 kDa, according to this finding. Individual phenolic compound levels in dried UFP samples were similar to RH, implying that the majority of phenolic components in dried rice bean protein hydrolysate were smaller than 3 kDa. With increasing drying temperature, gallic acid, p-coumaric acid, catechol, epicatechin and naringenin levels in dried UFP samples were decreased. The antioxidant capacity of dried rice bean hydrolysate was discovered to be due to phenolic components (gallic acid, epicatechin, catechol, ferulic acid, and rutin), which were found to be more prevalent than peptide fractions. As a result, rice bean hydrolysates could bring novel health advantages, which could lead to the development of nutraceuticals and food products.

A Comprehensive Survey of Phenolic Constituents Reported in Monofloral Honeys around the Globe.

The aim of this review is to provide a comprehensive overview of the large variety of phenolic compounds that have to date been identified in a wide range of monofloral honeys found globally. The collated information is structured along several themes, including the botanical family and genus of the monofloral honeys for which phenolic constituents have been reported, the chemical classes the phenolic compounds can be attributed to, and the analytical method employed in compound determination as well as countries with a particular research focus on phenolic honey constituents. This review covers 130 research papers that detail the phenolic constituents of a total of 556 monofloral honeys. Based on the findings of this review, it can be concluded that most of these honeys belong to the Myrtaceae and Fabaceae families and that Robinia (Robinia pseudoacacia, Fabaceae), Manuka (Leptospermum scoparium, Myrtaceae), and Chestnut (Castanea sp., Fagaceae) honeys are to date the most studied honeys for phenolic compound determination. China, Italy, and Turkey are the major honey phenolic research hubs. To date, 161 individual phenolic compounds belonging to five major compound groups have been reported, with caffeic acid, gallic acid, ferulic acid and quercetin being the most widely reported among them. HPLC with photodiode array detection appears to be the most popular method for chemical structure identification.

Novel Bio-Functional Aloe vera Beverages Fermented by Probiotic Enterococcus faecium and Lactobacillus lactis.

Aloe vera has been medicinally used for centuries. Its bioactive compounds have been shown to be very effective in the treatment of numerous diseases. In this work, a novel functional beverage was developed and characterized to combine the health benefits of probiotic bacteria with the Aloe vera plant itself. Two Aloe vera juices were obtained by fermentation either by a novel isolated Enterococcus faecium or a commercial Lactococcus lactis. The extraction of Aloe vera biocompounds for further fermentation was optimized. Extraction with water plus cellulase enhanced the carbohydrates and phenolic compounds in the obtained extracts. The biotransformation of the bioactive compounds from the extracts during fermentation was assessed. Both probiotic bacteria were able to grow on the Aloe vera extract. Lactic acid and short-chain fatty acids (SCFA) together with fourteen individual phenolic compounds were quantified in the produced Aloe vera juice, mainly epicatechin, aloin, ellagic acid, and hesperidin. The amount of total phenolic compounds was maintained through fermentation. The antioxidant activity was significantly increased in the produced juice by the ABTS method. The novel produced Aloe vera juice showed great potential as a functional beverage containing probiotics, prebiotics, SCFA, and phenolic compounds in its final composition.

Browning Development and Antioxidant Compounds in White Wines after Selenium, Iron, and Peroxide Addition

The effect of oxidation on the organoleptic properties of white wines mostly involves increased browning color, loss of the fruity aromas, and appearance of unpleasant odors. Browning, however, is known to be related with polyphenol oxidation and therefore it may be delayed by the presence of antioxidants such as selenium (Se) and SO2. On the other hand, the presence of oxidants such as metal ions and H2O2 can accelerate browning and oxidation phenomena. The browning capacity, the phenolic composition (both total and individual contents of flavanols and hydroxycinnamic acids), the antioxidant activity, and the SO2 content of Assyrtiko white wines were studied after the addition of Fe2+ and H2O2 and Se at two temperatures, employing an accelerated test. Browning was approached from a kinetic point of view, and the study was focused on the implication of oxidants and antioxidants on browning rate, paying particular attention to the content of major redox-active polyphenols, including substances with an o-diphenol feature, such as flavanols and hydroxycinnamic acids. The results showed that after the addition of oxidants it was possible to significantly accelerate the rate of browning development (up to 4.7 and six times) depending on the temperature and the concentration of the added compounds. The presence of Se protected wine color and preserved total SO2 at 35 °C, while at 50 °C, these effects were not observed. Total flavanol content decreased upon heating, while total hydroxycinnamic content showed a slight increase. Similarly, the content of the individual phenolic compounds (with the exception of caffeic acid and (+)-catechin at 35 °C) was decreased with oxidant addition, while Se addition was not adequate to prevent or even promote their oxidation.

Genotypic and environmental variations in phenolic acid and avenanthramide content of Canadian oat (Avena sativa)

Phenolic compounds (PC) in oat may possess health promoting properties. This study evaluated the effect of genotype, environment, and their interaction on the phenolic acid and avenanthramide (AVN) concentration in Canadian oat. Six cultivars were grown at eight locations across Canada in a randomised complete block design with three field replicates. Free PCs were extracted from oat groat flour and analysed using a UPLC–PDA system. The cumulative concentration of free PCs and AVN ranged from 58 to 350 and 9 to 244 µg/g, respectively. The effect of environment was significant (p < 0.0001) for the concentration of all PCs. Cultivar differences significantly influenced the concentration of all PCs but AVNs A and B. The growing location explained > 68% of the variation in the concentration of AVN. Thus understanding the genotypic and environmental triggers of individual PCs may help agronomists and breeders strategize in selecting and growing oat cultivars of interest.

Extraction of Bioactive Metabolites from Achillea millefolium L. with Choline Chloride Based Natural Deep Eutectic Solvents: A Study of the Antioxidant and Antimicrobial Activity

In this study, the extraction efficiency of natural deep eutectic solvents (NADES) based on choline chloride as a hydrogen bond acceptor (HBA) and five different hydrogen bond donors (HBD; lactic acid, 1,4-butanediol, 1,2-propanediol, fructose and urea) was evaluated for the first time for the isolation of valuable bioactive compounds from Achillea millefolium L. The phytochemical profiles of NADES extracts obtained after ultrasound-assisted extraction were evaluated both spectrophotometrically (total phenolic content (TPC) and antioxidant assays) and chromatographically (UHPLC-MS and HPLC-UV). The results were compared with those obtained with 80% ethanol, 80% methanol, and water. The highest TPC value was found in the lactic acid-based NADES (ChCl-LA), which correlated with the highest antioxidant activity determined by the FRAP analysis. On the other hand, the highest antiradical potential against ABTS+• was determined for urea-based NADES. Phenolic acids (chlorogenic acid and dicaffeoylquinic acid isomers), flavones (luteolin and apigenin), and their corresponding glucosides were determined as the dominant individual phenolic compounds in all extracts. The antibacterial and antifungal properties of the extracts obtained against four bacterial cultures and two yeasts were evaluated using two methods: the agar dilution method to obtain the minimum inhibitory concentration (MIC) and the minimum bactericidal or fungicidal concentration (MBC or MFC), and the disc diffusion method. ChCl-LA had the lowest MIC and MBC/MFC with respect to all microorganisms, with an MIC ranging from 0.05 mg mL−1 to 0.8 mg mL−1, while the water extract had the weakest inhibitory activity with MIC and MBC/MFC higher than 3.2 mg mL−1.

Quercus ilex leaf as a functional ingredient: Polyphenolic profile and antioxidant activity throughout simulated gastrointestinal digestion and antimicrobial activity

Quercus ilex leaf constitute a rich source of bioactive compounds, especially phenolic compounds, with health and technological properties. In this study, the influence of in vitro gastrointestinal digestion on the bioaccessibility and bioactivity of phenolic compounds from ground leaf (GL) and leaf powder extract (PE) was evaluated for the first time. The GL showed an increase in antioxidant capacity, total phenolic content and individual phenolic compounds identified in the oral and gastric phase, decreasing in the intestinal and absorption (dialysis) phases, while PE showed a slight decrease in the oral and gastric phase and a more pronounced reduction in the last phases. Although the content of phenolic compounds and the antioxidant capacity were higher in the initial PE, the bioaccessibility (55.27% in GL vs. 34.23% in PE) and the recovery in the last step of the gastrointestinal tract in the colon-available fraction (29.24% in GL vs. 27.90% in PE) were higher in GL. The PE showed high antimicrobial activity against Escherichia coli, Listeria monocytogenes, Salmonella Typhimurium, Yersinia enterocolitica and Staphylococcus aureus, showing minimum inhibitory concentration values between 1 and 5 mg/mL. These results showed the complexity and richness of Q. ilex PE and GL in phenolics with high antioxidant and antimicrobial activity, underlining their use as a source of biofunctional compounds for the development of novel food additives and nutraceuticals.

Impact of Different Drying Temperatures onIn VitroAntioxidant and Antidiabetic Activities and Phenolic Compounds of Wild Guava Leaves Collected in the Central Highland of Vietnam

Most biologically natural compounds are very sensitive and easily degradable under drying conditions. This study aimed to investigate the effect of drying temperature on the contents of phenolic compounds and in vitro antioxidant and antidiabetic activities of wild guava leaves. Wild guava leaves were dried at 40 °C, 50 °C, 60 °C, 70 °C, and 80 °C, as well as sun drying (SD). The total phenolic and flavonoid contents (TPC and TFC) were measured using the colorimetric method. Antioxidant activity was determined by the 2,2-diphenyl-2-picrylhydrazyl hydrate (DPPH) and 2,2-azino-bis(3-ethylbenzothazoline-6-sulfonic acid (ABTS) radical scavenging activity assays. In vitro antidiabetic activity was measured by assessing α-glucosidase and α-amylase inhibitory activities. The contents of individual phenolic compounds were determined using ultra-performance liquid chromatography (UPLC). The principal component analysis (PCA) results revealed that hot air drying at different temperatures had significantly different effects on the bioactive compounds and biological properties of guava leaves. Drying at high or low temperatures resulted in a higher degradable rate of bioactive compounds leading to a weakening of the biological properties. Drying at 50 °C resulted in high TPC and TFC as well as the highest in vitro antioxidant and antidiabetic activities. Furthermore, the highest contents of gallic acid, catechin, rutin, quercetin, apigenin, quercitrin, vitexin, and apigenin-7- O-D-glucopyranoside were found in samples dried at 50 °C, whereas the highest contents of chlorogenic acid, epicatechin, and ellagic acid were observed in samples dried at 60 °C. Therefore, drying at 50 °C was the suitable temperature for retaining valuable biological compounds in wild guava leaves.

Influence of the time of bilberry (Vaccinium myrtillus L.) addition on the phenolic and protein profile of beer.

In recent years, there has been an increased fruit addition to the brewing process, especially in craft breweries. Fruit addition leads to changes in the organoleptic characteristics and chemical composition of beers. Bilberries are rich in phenolic compounds and possess significant antioxidant capacity. The effects of bilberry addition and brewing process parameters on the changes in the phenolic and protein profile of beer have not been sufficiently studied. The aim of this research was to investigate the changes in the individual phenolic compounds and the protein fractions in beer when bilberries were added at different maturation stages. An infusion mashing method was applied for the purpose of obtaining wort with an original extract of 14&deg;P after boiling. Pilsner malt, bitter and aromatic hops 60/40 (Perle and Cascade, respectively), dry yeast Saccharomyces pastorianus (carlsbergensis) Saflager W 34/70, and bilberries (Vaccinium myrtillus L.) were used. All processes were conducted in a Home Brew 50 all-in-one 50 dm3 brewing system. The fermentation was carried out in a stainless steel cylindroconical fermenter at a temperature of 14&deg;C. The &ldquo;green beer&rdquo; was transferred to small stainless-steel fermenters after 60% of the original wort extract had been fermented. The maturation continued for 14 days at 14&deg;C, and the beer lagering for 5 days at 2&deg;C. The bilberries were pasteurised in a water bath for 10 minutes at 70&deg;C. After cooling, they were added to small fermenters at a concentration of 167 g/dm3 at the beginning and on the seventh day of beer maturation. All variants were carried out in duplicate. After lagering, the beer was bottled using a &ldquo;beer gun&rdquo;. The beer samples from the experiments were filtered on the day of bottling and frozen until analysis. HPLC/UV-VIS and electrophoresis were used to determine the phenolics and proteins, respectively. The total monomeric anthocyanins were determined by the pH differential method. The original wort extract and alcohol concentration were evaluated, and the sensory analysis was performed according to EBC standard methods. The changes in 10 phenolic acids, 7 flavonoids, and 10 protein fractions in beer with bilberries added at the beginning and on the seventh day of maturation were studied. The addition of bilberries led to an increase in the phenolic acid (3-fold) and flavonoid (6.2-fold) concentrations. The highest enrichment was observed in terms of rutin, chlorogenic, caffeic, and 3,4-dihydrobenzoic acids. Rosmarinic acid and monomeric anthocyanins were only detected in the bilberry beers. Chlorogenic and neochlorogenic acids, rutin, and catechin dominated in the bilberry beers. Neochlorogenic and gallic acids, epicatechin, and catechin dominated in the bilberry-free beers. The addition of bilberries reduced the protein content by 93 to 96%. The number of protein fractions decreased from 10 to 4. The influence of the bilberry addition time on the phenolics and proteins was different, and it affected the individual protein fractions in a different way. More phenolic acids and flavonoids were determined when bilberries were added at the beginning of maturation. The losses of some protein fractions were higher at the beginning of maturation and of others on the seventh day of maturation, whereas the addition time did not matter for some of the fractions. This study provides new information related to the changes in the phenolic and protein profile of beer with bilberries depending on the time of bilberry addition during beer maturation. The protein concentration and number of protein fractions decreased dramatically. In spite of the significant protein losses, the bilberry addition improved the phenolic profile of the beer and its organoleptic characteristics. The presence of more phenolic compounds is related to the antioxidant capacity respective to the biological value of beer. Further research in this direction is needed.