Extraction of antioxidant and antimicrobial compounds from Inga marginata Willd bark and pulp using different extraction techniques and phytochemical characterization

This study aimed to identify the least aggressive and highest yield extraction method to obtain bioactive compounds from Inga marginata Willd fruits, determine the chemical components, and evaluate the extracts’' antimicrobial and cytotoxic activity. The extraction efficiency was expressed by the total phenolic and total flavonoid content and antioxidant activity (DPPH, IC₅₀, and ORAC) using conventional, ultrasound, and microwave-assisted extraction. The highest bioactive compound content was achieved using 5 min at 60 °C for total phenolic content (214.98 mg GAE g⁻¹), total flavonoid content (22.90 mg EQ g⁻¹), DPPH (45.98 μmol TEAC g⁻¹), inhibitory capacity (0.80 mg mL⁻¹), and ORAC (167.25 μmol Trolox g⁻¹) using ultrasonic extraction, and the extract inhibited the growth of all microorganisms tested. Thirteen chemical compounds were determined by ESI-ToF-MS, confirming the high phytochemical capacity of the extract. Lastly, the Inga extract showed no cytotoxicity at the concentrations used.     

Antioxidant profiling of native and modified cereal brans

Bran is detached from cereals during roller-milling operations and considered as a byproduct of milling. Bran carries phenolics and antioxidants in appreciable quantities which can be heightened by modification. In the present project, four cereals were under study that is, wheat, barley, millet and sorghum. Bran was separated from cereal grains and was subjected to size reduction that is, fine (1 mm) and coarse (2 mm) and enzymatic modification by using xylanase and cellulase. Total phenolic content (TPC), total flavonoids content (TFC) and phytic acid were determined spectrophotometrically and phenolic acids through HPLC. TPC and TFC were recorded highest in xylanase-treated millet bran (0.304 mg GAE g⁻¹ and 211.42 μg g⁻¹ QE respectively). In vitro antioxidant activity assessed by DPPH and FRAP was found to be highest in coarse millet bran (89.51% inhibition) and native sorghum bran (722.52 μMFeSO4 g⁻¹) respectively. Phytic acid was observed highest in xylanase-treated barley bran (5.80 g per 100 g).     

Pleurotusostreatus and Agaricus subrufescens: investigation of chemical composition and antioxidant properties of these mushrooms cultivated with different handmade and commercial supplements

In this study, the chemical composition, total phenolic content and antioxidant activity (DPPH, ORAC and FRAP assays) of A. subrufescens and P. ostreatus, cultivated with handmade and commercials supplements, were compared. Additionally, the compounds ergosterol, saccharopine, and hexitol were identified in A. subrufescens by HPLC-MS/MS. The antioxidant compound p-coumaric acid and dihexoses was found in both mushroom species. A. subrufescens presented higher total phenolic content (73.8 ± 0.6 mg GAE 100 g⁻¹) and antioxidant activity than P. ostreatus (16.6 ± 0.5 mg GAE 100 g⁻¹). The handmade supplement based on the waste of noble grains presented statistically similar phenolic content to the mushrooms cultivated with commercial ones Spawn Mate II SE (86.1 ± 1.4 and 92.9 ± 0.3 mg GAE 100 g⁻¹, respectively). Therefore, the results support the use of handmade supplements based on agro-wastes as a viable alternative to the use of high-cost commercial ones.     

Comparison of lignans and phenolic acids in different varieties of germinated flaxseed (Linum usitatissimum L.)

The study aimed to evaluate the biosynthesis and accumulation of lignans, phenolic acids and also the antioxidant activities in 15 varieties of flax sprouts. The differential contents of lignans (13.30–8987 μg g⁻¹) and phenolic acids (72.55–597.1 μg g⁻¹) among 15 varieties of flax sprouts were observed. The total antioxidant activities ranged from 147.2 to 332.8 μmol TE g⁻¹ in the flax sprouts. The expression levels of five genes in the lignin synthetic pathway were analysed using RT-qPCR, and the results showed dramatical differences among different flax sprouts. Relatively dispersed analysis was showed by principal component analysis (PCA), and 15 flax sprouts were grouped by hierarchical cluster analysis (HCA) based on their phenolic acids, lignan compounds, length, gene expression and antioxidants after germination, primarily in relation to variety specificity. Present results would be instructive guidance for bio-fortification breeding and functional foods innovation in flaxseeds.     

Identification and quantification of phenolic compounds in kernels,oil and bagasse pellets of common walnut (Juglans regia L.)

Individual phenolic compounds, total phenolic content and antioxidant potential were assessed in kernels, oils and bagasse pellets (residues of oil pressing) of different walnut cultivars. Twenty-seven phenolic compounds were detected in kernels and pellets conducting high-performance liquid chromatography–tandem mass spectrometry. The main polyphenolic subclass comprised hydrolysable tannins, which accounted approximately 60.80% (kernels) and 61.66% (pellets) of the total phenolics identified (TPI). Walnut oil was poor in phenolics and contained only six different compounds but due to their low content (from 0.15 to 1.44 μg g^− 1) just two compounds have been identified. Glansreginin A and glansreginin B were detected in all analyzed walnut products. A comparison of average amount of total phenolic content revealed that walnut oil contains as much as 154 fold less phenolics (0.05 mg GAE g^− 1 FW) compared to kernels (7.7 mg GAE g^− 1 FW) or pellets (7.9 mg GAE g^− 1 FW).     

Microwave and ultrasound assisted extraction of phytocompounds from black jamun pulp: Kinetic and thermodynamics characteristics

The present study focuses on the extraction of phenolic compounds, anthocyanin and antioxidants from black jamun pulp by microwave and ultrasound assisted extraction process. The microwave-assisted extraction was carried out for 240 s at microwave power level of 100–400 W. The yield of total anthocyanin and total phenolic content in the microwave assisted extraction process at 400 W power level after an extraction period of 240 s was 8.197 mg of C3G g⁻¹ and 37.671 40.632 mg GAE g⁻¹, respectively. The ultrasound assisted extraction was performed at temperatures of 40, 50, 60, and 70 °C for 150 min. In the ultrasound assisted extraction at a sonication temperature of 70 °C, the yield of anthocyanin was 8.525 mg of C3G g⁻¹, while the yield of the phenolic compound was 47.331 mg GAE g⁻¹. The pseudo-second order model was found to be the most suitable model to represent the extraction kinetics of anthocyanin, phenolic compounds, and antioxidant activity of black jamun pulp. The effective diffusion coefficient for ultrasound assisted extraction of phenolic components, anthocyanin, and antioxidant activity in the temperature range of 40-70 °C was 5.704× 10⁻¹²–10.515 10⁻¹², 2.485× 10⁻¹² -8.507× 10⁻¹², and 2.061× 10⁻¹²–11.977 × 10⁻¹² m².s⁻¹ respectively. The negative Gibbs free energy change values for extraction of phenolic compounds and anthocyanin specified that the reaction was feasible and spontaneous. Thermodynamic parameters such as positive enthalpy change and positive entropy change indicated that the ultrasound assisted extraction process was endothermic and irreversible in nature.     

Quantitative UPLC‐MS/MS analysis of chlorogenic acid derivatives in antioxidant fractionates from dandelion (Taraxacum officinale) root

While qualitative studies have identified chlorogenic acids in antioxidant extracts, particularly ethyl acetate‐derived extracts, of Taraxacum officinale, quantitative analysis of these phenolic compounds remains largely unreported for this species. In this study, bioactivity‐guided fractionation of an antioxidant crude ethyl acetate extract (DPPH = 295.481 ± 0.955 mg TE g^?1 extract) from T. officinale root resulted in a number of reverse‐phase fractions that demonstrated high antioxidant activity (DPPH = 1058.733–1312.136 mg TE g^?1 extract), stronger than that of the synthetic antioxidant Trolox^®. UPLC‐MS/MS screening of these fractions for the presence of selected mono‐ and di‐caffeoylquinic acids revealed large quantities of 1,5‐dicaffeoylquinic acid present in several fractions (853.052–907.324 μg mg^?1), respectively. Due to the antioxidant potency and high levels of 1,5‐dicaffeoylquinic acid observed in these fractions, it was concluded that specifically this chlorogenic acid derivative is a major contributor to the antioxidant efficacy of dandelion root.     

The effect of simulated digestion on the composition of phenolic compounds and antioxidant activities in lychee pulp of different cultivars

Simulated gastric fluid (SGF) and intestinal fluid (SIF) digestion were used to evaluate the effects of digestion on the composition of phenolic compounds and antioxidant capacities of the pulp of six lychee cultivars. Caffeic acid, ferulic acid, procyanidin B2, epicatechin, A-type procyanidin trimer, procyanidin A2, quercetin-3-rutinose-7-rhamnoside, rutin and isoquercitrin were quantified using HPLC-DAD. Lychee pulp had high concentrations of procyanidin B2 (0.30~15.53 mg g⁻¹), procyanidin A2 (0.29~0.52 mg g⁻¹) and quercetin-3-rutinose-7-rhamnoside (0.16~0.45 mg g⁻¹). SGF and SIF Digestion, which significantly decreased the concentration of procyanidin B2, epicatechin and quercetin-3-rutinose-7-rhamnoside. But observably increased the concentration of procyanidin A2. Compared with deionized water treatment (DW), the total phenolic content (TPC) and total flavonoid content (TFC) of different lychee pulps significantly increased after SGF and SIF digestion. After SGF digestion, the ferric ion reducing antioxidant power (FRAP) of lychee pulps increased while the ABTS+ free radical scavenging ability (ABTS) had a slight decline. This shows that simulated digestion improves the bioactive component and antioxidant activity of different varieties of lychee pulp.     

Mango (Mangifera indica L.) leaf extracts as ingredient for the formulation of functional beverages with biological activity

The biological activity of mango leaf extracts from different mango varieties was evaluated in terms of total phenolic content, flavonoids, antioxidant activity and inhibition of α-amylase and α-glucosidase enzymes. Leaf extract-based beverages were formulated and evaluated for some physicochemical, microbiological and sensory properties. Results indicated that the extract from 'Tommy Atkins' mango leaves had the highest total phenols content (137.08 mg of GAE g⁻¹) and antioxidant activity (DDPH = 38.26 mg TEAC 100 g⁻¹; ABTS = 59.13 mg TEAC 100 g⁻¹). The beverage formulated with 20% leaf extract presented the highest percentage of antioxidant activity (38.63%) and inhibition of enzymes α-amylase (41.9%) and α-glucosidase (37.53%). All beverages presented a yellow hue and consumers rated it with a degree of liking between 4.8 and 7.3 according to a hedonic scale. Results showed that the biological properties of beverages could be an alternative for the control of free radicals and glucose levels.     

Bioactive compounds and antioxidant activities of Brazilian hop (Humulus lupulus L.) extracts

Bioactive compounds from Brazilian hop (Humulus lupulus L.) cultivars were extracted by ultrasound and their phenolic profile compared with commercial hop from the USA. The most effective extraction conditions (solution of ethanol 49%, at 52 °C and a solid/liquid ratio of 1 g per 34 mL) for the total phenolic compounds (TPC) were determined using a Central Composite Rotatable Design. The Brazilian hop showed higher content of TPC (33.93 ± 0.67 mg GAE g⁻¹), total flavonoids (54.47 ± 0.10 mg QE g⁻¹) and higher antioxidant activity (ABTS: EC₅₀ 21.29 ± 1.36 μL mL⁻¹; DPPH: EC₅₀ 3.91 ± 0.17 μL mL⁻¹) when compared with the USA hop. The main phenolic compounds present in the extracts were the flavonoids isoquercitrin and quercetin. The antioxidant properties of the Brazilian hop extract had not been reported yet in the literature for this raw material, thus showing potential to be incorporated in polymeric films used as active packaging.     

Evaluation of flavonoid and polyphenol constituents in mulberry leaves using HPLC fingerprint analysis

The mulberry leaf is a promising dietary source of antioxidants due to its high levels of beneficial compounds. To further examine its antioxidant properties, twelve batches of authenticated mulberry leaf, with total flavonoid contents (TFC) ranging from 24.34 mg g⁻¹ DW to 58.42 mg g⁻¹ DW and total polyphenol content (TPC) ranging from 11.49 mg g⁻¹ DW to 30.03 mg g⁻¹ DW, were investigated. According to Spearman’s coefficient, antioxidant activities, including the DPPH radical scavenging assay and the ferric reducing antioxidant power (FRAP), were positively correlated with TFC and TPC. The HPLC-DAD analysis results identified the characteristic fingerprint peaks in mulberry leaves as chlorogenic acid, rutin, quercetin 3-O-glucoside and kaempferol 3-O-glucoside, all of which directly contribute to the antioxidant capacity of mulberry leaves. Notably, young mulberry leaves showed higher antioxidant capacity than those of mature leaves. These promising results help create a compelling case for future development of mulberry leaf products.     

UHPLC-ESI-QTOF-MS phenolic profiling and antioxidant capacity of bee pollen from different botanical origin

In this work, bee pollen samples from different botanical origin were investigated for antioxidant capacity. Thereafter, a phenolic profiling was produced through a mass spectrometric untargeted metabolomic approach. Marked differences were identified in TPC, ranging from 4.2 (Magnolia) to 29.6 mg g⁻¹ GAE (Lamium). Wide differences were also recorded in antioxidant capacity (ORAC, ABTS and DPPH assays). Untargeted profiling allowed annotating 467 compounds with flavonoids being the most frequent class of phenolics followed by phenolic acids, tyrosols, lignans and other. OPLS-DA clearly discriminated the most represented floral families (Umbelliferae, Rosaceae and Fabaceae), suggesting, thus, that botanical origin leaves a characteristic phenolic signature in pollen. Overall, 35 phenolics accounted for most of the discrimination, with flavonoids being the most represented class. Despite the fact that further research is needed, the phenolic profile of bee pollen is a promising tool to investigate the botanical origin.     

Comparative study of the phenolics,antioxidant and metagenomic composition of novel soy whey-based beverages produced using three different water kefir microbiota

Water kefir microbiota was used to develop novel soy whey-based beverages that have antioxidant activity. In the present study, comparative phenolics, antioxidant and metagenomic composition of the soy whey beverages fermented using three different water kefir microbiota, named WKFS-A, WKFS-B and WKFS-C were investigated. WKFS-B beverage had the highest concentrations of isoflavone aglycones (208.73 ± 2.78 mg L⁻¹) and phenolic acids (132.33 ± 3.41 mg L⁻¹) compared with WKFS-A (193.88 ± 1.15 mg L⁻¹) and (91.73 ± 2.34 mg L⁻¹) and WKFS-C (160.63 ± 1.76 mg L⁻¹) and (97.13 ± 2.63 mg L⁻¹), respectively. The WKFS-B also showed higher DPPH and ABTS radical scavenging activity and ferric reducing antioxidant power compared with WKFS-A and WKFS-C beverages. Microbial species diversity index analysis showed that a higher concentration of isoflavone aglycones, phenolic acids and increased antioxidant activity in the WKFS-B beverage correlates with the higher relative abundance of Lactobacillus genus. This study thus revealed that Lactobacillus dominated water kefir microbiota produces soy whey beverages with high phenolic acids, isoflavone aglycones and antioxidant activity.     

An investigation into green coffee press cake as a renewable source of bioactive compounds

The residual biomass of coffee, obtained after the oil extraction from coffee beans, called coffee beans residual press cake, has been attracted interest as a source of compounds with antioxidant capacity. This study investigated the effects of ethanolic and methanol-acetone extracts of green coffee beans (GCB) and its residual press cake (GCC) on the phenolic composition and antioxidant capacity. Antioxidant capacity was assayed through five different methods (total phenolic compounds, •DPPH, ABTS, FRAP and β-carotene bleaching assay), and the phenolic profile of the samples through High Performance Liquid Cromatography. GCB and GCC enclosed chlorogenic (55.16 and 64.96 mg g⁻¹, respectively) and caffeic (25.07 and 44.37 mg g⁻¹, respectively) acids as the major components, and the cake presented higher antioxidant capacity than the actual green bean. Antioxidant capacity was higher for GCC extracted with methanol and acetone. This study on the evaluation of the effects of the type of solvent on the bioactive compounds from GCB and GCC showed that this by-product can be a source of new value-added products, such as phenolic antioxidant adjuncts for food or pharmaceutic processing.     

Production,iron analysis and consumer perception of functional Thai Sinlek iron rice (Oryza sativa) drink

We produced the iron rice (IR) drink, determined the relevant chemical composition and antioxidant activity and tested the consumers’ degree of satisfaction. IR grains were digested with α-amylase and analysed chemical composition and antioxidant activity, while the hydrolysate (pH 4.0) and flavouring agents were added for final preparation of the IR drink. The IR hydrolysate contained a total iron content of 13.9 mg g⁻¹, a total phenolic content of 1.33 ± 0.07 mg gallic acid equivalent g⁻¹ and γ-oryzanol of 70.12 ± 2.7 mg kg⁻¹ rice grain, all of which inhibited the generation of free radicals in a concentration-dependent manner. The IR drink was composed of flavonoids and phenolic acids for which kaempferol was predominant. The members of all three groups of elderly subjects who consumed the low-dose IR (1.47 mg iron/100 mL), high-dose IR (2.74 mg iron/100 mL) and white rice (WR; 0.5 mg iron/100 mL) drinks expressed satisfaction and interest with the beverages at 91.2%, 100% and 88.9%, respectively. In terms of sensory evaluation, the low-dose IR drink revealed a higher acceptance rating than high-dose IR and WR (P < 0.05). Notably, the Sinlek rice drink was abundant with iron, anti-oxidative phenolics and γ-oryzanol, for which consumers expressed an overall degree of acceptance (8.1 ± 1.1).     

Fabrication and stability of Pickering emulsions using moringa seed residue protein: Effect of pH and ionic strength

Food-grade Pickering emulsions stabilised by plant protein have low toxicity. In this study, to explore the potential of Moringa seed residue protein (MSRP) as Pickering particles, MSRP was obtained from Moringa seed residue and used to fabricate emulsions at different pH and ionic strength. The molecular weight of MSRP ranged between 5 and 25 kDa. The particle diameter of MSRP with positive charge was > 233 nm. The highest MSRP solubility was achieved at pH 5 (206.89 mg g⁻¹) and 0.2 M NaCl (202.55 mg g⁻¹). MSRP generated an excellent interfacial layer as verified by confocal laser scanning microscope imaging, and had lower droplet size, and formed well-developed elastic networks at pH 5 and 0.2 M NaCl. MSRP-stabilised emulsion through steric hindrance, possessing excellent tolerance in salt (< 0.2M) and weakly acid (pH 5–7) environment. Our study finds MSRP can be used as potential Pickering particles applying in food and beverages industries.     

Solvent extraction and in vitro simulated gastrointestinal digestion of phenolic compounds from purple sweet potato

The total content of phenolic compounds in purple sweet potato (PSP) was determined and the release of such compounds from PSP in gastrointestinal digestion was studied in vitro. The extraction conditions for the maximum recovery of free phenol (FP) and bound phenol (BP) from PSP were determined by response surface methodology (RSM). The maximum recovery of FPPSP was 14.16 ± 0.87 mg GAE per g short for dry weight (DW), which was obtained using 60% (v/v) ethanol maceration with a liquid–solid ratio of 57.21:1 (mL g⁻¹) at 51.93 °C for 2.12 h. The maximum recovery for BPPSP was 7.54 mg GAE per g DW, which was obtained upon hydrolysis with 1.87 mol L⁻¹ NaOH at a liquid–solid ratio of 35.93:1 (mL g⁻¹) for 4.74 h. The maximum phenolic content was released after 1 and 2 h for the in vitro gastric and intestinal digestion respectively. The release of the phenolics was promoted by pepsin and gastric acid during gastric digestion, while it was further promoted by trypsin during intestinal digestion.     

Evaluation of antioxidant activity of olive leaf extract obtained by ultrasound-assisted extraction and their antimicrobial activity against bacterial pathogens from food

The aim of the present study was to evaluate and compare the phenolic content and antioxidant and antimicrobial properties of olive leaf extracts obtained by ultrasound-assisted extraction (UAE) and conventional extraction (CSE). UAE of olive leaf extracts yielded a higher total phenolic content (TPC) and total flavonoid content (TFC) of 14.31% and 19.50%, respectively. Higher antioxidant activities were found from the extracts prepared with UAE (for 18.5%, 12.5%, 10.9% and 17.6% higher determined by DPPH, ABTS, FRAP and CUPRAC methods, respectively). Good antibacterial inhibitory activity (as MIC and MBC) was observed against both Y. enterocolitica and S. aureus (1.40 ± 0.40 mg mL⁻¹ and 4.00 ± 1.60 mg mL⁻¹, respectively) with the extract prepared with UAE. In conclusion, olive leaf extracts prepared with UAE exhibited higher antioxidant and antimicrobial activities against common food-borne pathogens than CSE extracts and thus could be beneficial in ensuring food quality and food safety.     

Effect of amino acids on Maillard reaction product formation and total antioxidant capacity in white pan bread

Maillard reaction products (MRPs) can be an important dietary antioxidant source. Bread is the most popular bakery product; however, limited information is available on the antioxidant activities of MRPs generated during bread-baking. This paper reports the effect of different amino acids on bread properties, melanoidin formation and antioxidant activities. Totally six amino acids at four different levels were evaluated. Increasing the amount of amino acid led to darker bread crust, higher melanoidin content and stronger antioxidant activity. Among the six amino acids, bread with glycine had the highest melanoidin content and ABTS radical scavenging activity up to 1079.77 ± 8.43 μmol TE mg⁻¹. Bread with lysine had the highest DPPH radical scavenging activity up to 281.97 ± 10.52 μmol TE mg⁻¹. Bread with alanine had the highest crust metal chelating activity compared with others. Adding certain dietary amino acids is a potential approach to enhance the antioxidant capacity of bread products.     

Effect of fermentation by Bacillus subtilis on antioxidant and cytotoxic activities of black rice bran

Black rice bran was fermented with Bacillus subtilis KU3 isolated from Korean traditional food, Kimchi. Antioxidant and cytotoxic activities of the fermented black rice bran were investigated. Total phenolic and anthocyanin contents decreased from 171.54 mg GAE g^?1 and 2.31 mg g^?1 to 139.13 mg GAE g^?1 and 2.12 mg g^?1, respectively, after fermentation. Antioxidant activities determined by 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) radical scavenging, β‐carotene bleaching and ferric thiocyanate assay were correlated with total phenolic and anthocyanin contents. Non‐fermented black rice bran extract (NFBE) showed greater antioxidant activities than fermented black rice bran extract (FBE). Cytotoxic activities measured by MTT assay showed that both NFBE and FBE had over 50% activities. The cytotoxic activities of FBE against MCF‐7 and HeLa cells were 71.65% and 68.07%, respectively, at 8.0 mg mL^?1, but those of NFBE were lower than 50%. These results suggested that the cytotoxic activity of black rice bran improved through fermentation, while antioxidant activity reduced.