Search Results (433)

This study investigated the effects of thermal processing and extraction solvents on the phytochemical composition, antioxidant potential, and cytotoxic activity of Sukhothai fragrant rice (Oryza sativa L.). Rice subjected to three processing methods, unprocessed (raw), popped/puffed and steam-cooked, was extracted using hot water or 70% (v/v) ethanol, yielding six extracts. Trans-ferulic acid, γ-oryzanol and anthocyanins were quantified using HPLC-DAD and HPLC-ESI-MS, while total phenolic and flavonoid contents, and antioxidant activities were evaluated using Folin–Ciocalteu, aluminium chloride, DPPH and ABTS assays. Cytotoxicity was assessed in Huh7 hepatocellular carcinoma cells. Water extracts consistently produced higher yields and contained greater total phenolic, flavonoid and anthocyanin contents, resulting in stronger antioxidant activity. Unprocessed rice water extract exhibited the highest trans-ferulic acid recovery and antioxidant capacity. Thermal processing, particularly steamed cooking, markedly reduced phytochemical contents, likely due to heat-induced degradation. In contrast, ethanolic extracts yielded lower quantities but higher concentrations of less polar bioactive compounds and exhibited greater cytotoxic effects. Overall, minimal thermal processing combined with aqueous extraction best preserved antioxidant compounds, while ethanolic extraction enhanced biological potency. These findings highlight the importance of processing intensity and solvent polarity in optimizing the nutraceutical and functional potential of black rice. Full article

Polyphenols, particularly anthocyanins, are associated with metabolic health benefits; however, whether anthocyanin extracts provide greater bioaccessibility than whole foods remain unclear. This study investigated the role of the food matrix in açaí berry, one of the richest natural sources of anthocyanins, by comparing polyphenol and anthocyanin bioaccessibility across freeze-dried whole fruit, crude extract, and purified extract. All samples underwent standardised INFOGEST in vitro digestion, and total polyphenol content (TPC), anthocyanins (ACN), and antioxidant activity were quantified using Folin–Ciocalteu, pH-differential, and DPPH assays, respectively. Intestinal-phase TPC % bioaccessibility was similar in whole fruit (58%) and crude extract (58%) but significantly lower in pure extract (43%). ACN bioaccessibility showed a pronounced matrix effect, with the highest retention in whole fruit (44%), followed by crude extract (32%), and the lowest retention in pure extract (12%). Antioxidant activity after intestinal digestion mirrored these patterns. Overall, these findings demonstrate that the natural açaí food matrix substantially preserves anthocyanin stability during digestion, resulting in higher bioaccessible levels than matrix-free extracts, suggesting that incorporating matrix components into anthocyanin-rich nutraceuticals may help support greater functional recovery during gastrointestinal digestion. Full article

Tiger nut (Cyperus esculentus L.) is a relatively neglected tuber crop with notable nutritional, functional, and ecological value. The primary objective of this study was to evaluate the biological properties and selected nutritional parameters of tiger nut tubers and oil, including antioxidant activity, total phenolic content (TPC), fatty acid (FA) profile, health-related lipid indices, and mineral composition. Methods: Natural and peeled tiger nut tubers, as well as commercially available tiger nut oil (yellow variety, Valencia, Spain), were analyzed. Antioxidant activity was measured spectrophotometrically using the DPPH method. The content of TPC was determined using the Folin–Ciocalteu assay. Fatty acid composition was analyzed by gas chromatography coupled with flame ionization detection, and these data were used to calculate the PUFA/SFA (P/S) ratio, atherogenicity (AI), thrombogenicity (TI) index, and hypocholesterolemic/hypercholesterolemic (h/H) ratio. Macro- and microelement contents were quantified using inductively coupled plasma optical emission spectrometry. Estimated daily intake (EDI), target hazard quotient (THQ), and total THQ (TTHQ) were calculated to assess potential health risks. Results: Natural tiger nut tubers exhibited substantially higher antioxidant activity and TPC compared to peeled tubers, suggesting that the peel is the primary reservoir of phenolic compounds. Strong antioxidant activity was observed in tiger nut oil (64.82 ± 2.59 mg TEAC/L). Oleic acid (C18:1cis n-9) was identified as the predominant FA across all samples, thus contributing positively to favorable health lipid indices (P/S > 0.50, low AI and TI, high h/H ratio). Potassium was the most abundant macroelement in natural and peeled tiger nut tubers. The overall trend of microelement levels in these samples was as follows: Al > Fe > Zn > Cu > Sr > Mn > Li > Ba > Se > As > Cr. All THQ and TTHQ values were below 1, indicating no appreciable health risk associated with consumption. Conclusions: These findings support the use of tiger nuts as a functionally valuable ingredient in health-oriented food products. Full article

Kombucha is a millennia-old beverage crafted from green or black tea and saccharides and fermented with a symbiotic culture of bacteria and yeast (SCOBY). This functional drink boasts health benefits, such as improved intestinal flora function, hepatoprotection and inhibition of amyloid fibers. It contains bioactive antioxidants, such as catechins, ascorbic acid, vitamins and other polyphenolic compounds. With kombucha’s rising popularity, the Food and Drug Administration (FDA) has implemented control procedures to ensure the quality and safety of this food product. Due to the antioxidant properties of the major bioactive compounds in kombucha, feasible and low-cost electroanalytical methods emerge as promising alternatives. The objective of this study was to evaluate the voltammetric behavior of kombucha samples to establish and compare their redox profiles and antioxidant activities. Thus, 18 kombucha samples were used, comprising commercial samples and samples prepared in the laboratory from different SCOBYs purchased from different countries, and analyzed by differential pulse voltammetry (DPV) and square wave voltammetry (SWV) on a carbon paste electrode (CPE). The electrochemical index (EI) values determined from the samples were used to establish their antioxidant activities. The EI values were also compared with spectrophotometric data from Folin–Ciocalteu (FC) and Ferric Reducing Antioxidant Power (FRAP) assays. Full article

Salvia dumetorum Andrz. ex Besser is a promising non-pharmacopoeial plant species with traditional medicinal potential. This study aimed to determine the optimal microwave-assisted extraction (MAE) conditions for obtaining a polyphenol-rich ethanolic extract from the S. dumetorum leaves. Dried and powdered leaves were extracted using 40% ethanol with different power of microwaves varying from 200 to 800 W and time of extraction 2–8 min. The extract was filtered, concentrated, and evaluated for yield, identification of phenolic compounds using high-performance liquid chromatography (HPLC), total phenolic content (TPC), and total flavonoid content (TFC). Extraction yields ranged from 2.20% to 25.80% based on dry weight. TPC and TFC were determined using Folin–Ciocalteu and aluminum chloride colorimetric assays, respectively, and are expressed as mg GAE/g and mg RUE/g of dry extract. The antioxidant activity of the extracts was evaluated using the DPPH (2,2-diphenyl-1-picrylhydrazyl radical) assay. According to HPLC analysis, the main phenolic components of the extracts were rosmarinic acid (1.78–2.95 mg/mL), chlorogenic acid (0.31–0.54 mg/mL), caffeic acid (0.11–0.20 mg/mL), rutin (up to 0.47 mg/mL) and ferulic acid (0.13–0.33 mg/mL); traces of myricetin were found only in isolated samples. The optimum extraction conditions were found to be 400 W microwave power, 8 min extraction time, one MAE cycle, and a 1:30 g/mL solvent-to-material loading ratio; TPC and TFC were evaluated as 35.23 ± 0.50 mg GAE/g DW and 19.94 ± 0.14 mg RuE/g DW, respectively, indicating the highest yield of polyphenolic compounds, antioxidant potential inhibiting 96.68% ± 0.27 of DPPH radicals, and IC₅₀ = 10.24 µg/mL. These findings highlight the efficiency of MAE in producing a bioactive ethanolic extract of S. dumetorum, which can be further explored for potential applications as a natural antioxidant in pharmaceutical or cosmetic formulations. Full article

Sustaining irrigated agriculture under drought conditions with alternative water sources such as saline groundwater requires understanding their effects on salt-tolerant crops like pistachio. During recent California droughts, pistachio trees planted in 2002, 2009, and 2011 were irrigated with high-saline water containing traces of boron (B) and selenium (Se). In 2018, irrigation was divided so that half of the trees received low-saline water, while the others continued under high-saline irrigation. Three years later, nuts were harvested to evaluate how irrigation quality affected seed coats, the main storage site of phenolic antioxidants. Sixty seed coat extracts from both irrigation treatments were analyzed for antioxidant capacity (ABTS, DPPH, FRAP and Folin–Ciocalteu assays). Nuts from the oldest trees (planted in 2002) had the highest antioxidant capacity. High-performance liquid chromatography (HPLC) identified gallic acid and nine flavonoids. Catechin, procyanidin B1, cyanidin-3-O-galactoside, and eriodictyol were most abundant in the oldest trees. Irrigation salinity significantly affected gallic acid, quercetin, and isoquercetin, with higher concentrations detected in seed coats from trees receiving continued high-saline irrigation. These compound-specific shifts, together with strong age-dependent patterns, provide insight into how long-term salinity exposure influences phenolic composition in pistachio seed coats. Full article

This study aimed to develop an efficient and environmentally sustainable method for extracting bioactive compounds from juçara palm (Euterpe edulis Mart.) fruit residues using deep eutectic solvents (DES) and conventional solvents, combined with ultrasound-assisted extraction (UAE). Seven DES formulations based on choline chloride (ChCl) and different hydrogen bond donors (glycerol, glucose, and organic acids) were prepared, and their performance was compared with water, ethanol, and ethanol/water mixtures. The phenolic composition, anthocyanins and antioxidant activity of the extracts were determined using spectrophotometric assays (Folin–Ciocalteu, DPPH, ABTS, and FRAP) and ESI–MS/MS analysis. The results showed that DES exhibited higher efficiency in recovering total phenolic compounds, anthocyanins and ABTS compared to conventional solvents, particularly in the ChCl–glycerol system. ESI–MS/MS analyses monitored around 40 phenolic compounds, including phenolic acids, flavanones, flavonoids, and anthocyanins. Acidic solvents favored anthocyanin extraction and stability, while ethanol- and glycerol-based systems provided broader compound profiles. The use of DES proved to be a green and selective alternative for obtaining extracts rich in bioactive compounds, enhancing the value of juçara residues and contributing to the sustainability of the species production chain. Full article

Background: Cereal bars are convenient vehicles for incorporating ingredients with functional value. In this context, the study aimed to formulate bars enriched with quinoa, amaranth, and calafate (Berberis microphylla) and evaluate their instrumental texture, total phenolic compounds, antioxidant capacity, nutritional composition, and sensory evaluation. Methods: Four formulations were developed, a baseline cereal bar with balanced ingredients (F1), a pseudocereal-enriched bar (F2), a high-calafate bar (F3), and an oat-only control bar (F4). Texture was measured using uniaxial compression, total phenolic compounds (TPC) were determined by the Folin–Ciocalteu method, and antioxidant capacity was assessed by the DPPH assay. The nutritional composition was theoretically estimated using food composition tables and dietary reference intakes (DRIs). Sensory evaluation was performed using affective tests, including acceptability, preference, purchase intention, and sensory attributes. Results: The formulations differed significantly in instrumental hardness. F3 had the highest total phenol content and the highest antioxidant capacity. The estimated nutritional composition showed that the bars provide adequate energy and relevant micronutrients (Ca, Mg, Fe, Zn), as well as bioactive compounds from calafate. Sensory evaluation showed that F2 obtained the highest overall acceptance and the highest acceptability index. Purchase intention did not differ between formulations. In the evaluation of attributes, the results indicate that intermediate hardness maximizes acceptance, while softer (F1) or harder (F3–F4) bars are less preferred. Conclusions: The incorporation of calafate enhances the phenolic and antioxidant profile in F3, while an intermediate hardness linked to the greater use of expanded pseudocereals favors consumer acceptance in F2. The observed differences confirm that the formulation design enables the modulation of functional, mechanical, and sensory properties in cereal bars. Full article

High-throughput colourimetric assays are widely used to screen phenolic phytonutrients in foods and plants, supporting discovery, quality control, and preliminary nutraceutical assessment. This review summarises the historical development, operating principles, and limitations of phenolic-based benchtop methods, and reports practical guidance for defensible application. The following colourimetric approaches are critically evaluated: Folin–Ciocalteu for total phenolics; AlCl₃-based and alternative total flavonoid methods; the pH-differential procedure for total monomeric anthocyanins; and tannin assays including vanillin–HCl, butanol–HCl (Porter), DMACA, protein-precipitation, and hydrolysable-tannin (rhodanine/ellagic-acid) protocols. For each method, common biases are identified, matrix interferences, reagent cross-reactivity, oxidative artefacts, dependence on calibration standard, and the chemical meaning of the readout is clarified. A best-practice framework is proposed: define the analytical target; pair complementary assays; pre-clean extracts; justify standards and wavelengths; control oxidation; validate spike-recovery and conversion checks; and contextualise outcomes using functional measures. A consistent conclusion emerges: no single method quantifies “total tannins” or “total flavonoids” across diverse matrices, and transparent reporting with method triangulation is essential for comparability and credible nutraceutical interpretation. The guidance consolidated here aims to standardise practice, minimise over- and underestimation artefacts, and strengthen the evidentiary value of data in food and nutraceutical research. Full article

Carrot (Daucus carota L.) is a widely consumed root vegetable, yet its aerial parts, including leaves and stems, are typically discarded as agricultural by-products, despite their potential biological value. This study comparatively evaluated the antioxidant and immunomodulatory properties of carrot aerial and root parts extracted using hot water or 50% ethanol. Four extracts were prepared: aerial part hot-water (AP-W), aerial part ethanol (AP-E), underground part hot-water (UP-W), and underground part ethanol (UP-E). The total phenolic content (TPC, expressed as gallic acid equivalents; GAE) and total flavonoid content (TFC, expressed as quercetin equivalents; QE) were quantified using the Folin–Ciocalteu and aluminum nitrate colorimetric methods, respectively. Antioxidant capacities were determined by ABTS and DPPH radical scavenging assays, cytotoxicity was assessed in RAW 264.7 macrophages via the MTT assay, nitric oxide (NO) levels were measured using the Griess reaction, and cytokine (IL-6, TNF-α) concentrations were analyzed by ELISA. Among the extracts, AP-E exhibited the highest TPC (28.3 ± 0.3 µg GAE/mg extract) and TFC (18.2 ± 2.3 µg QE/mg extract), corresponding to the strongest ABTS (92.3 ± 2.5%) and DPPH (72.4 ± 7.3%) radical scavenging activities. None of the extracts demonstrated cytotoxicity below 400 µg/mL. Under basal conditions, AP-W and UP-W significantly enhanced NO production (9.5 ± 1.3 µM and 7.7 ± 1.2 µM, respectively), while co-treatment with LPS markedly reduced NO levels in AS-E (2.3 ± 0.2 µM). Consistently, AP-W and UP-W elevated cytokine secretion (IL-6: 3462.1 ± 349.7 pg/mL and 1749.4 ± 55.4 pg/mL; TNF-α: 15,245.2 ± 771.0 pg/mL and 14,719.1 ± 329.8 pg/mL), whereas AP-E (400 µg/mL) significantly suppressed IL-6 (3938.6 ± 268.7 pg/mL) and TNF-α (11,869.0 ± 721.1 pg/mL) under LPS-stimulated conditions. Collectively, these results indicate that hot-water extracts of carrot parts exert immunostimulatory activity, whereas ethanol extracts possess potent anti-inflammatory potential. The aerial parts of carrots, often regarded as waste biomass, exhibit comparable or superior bioactivities to the roots, underscoring their potential utility as promising functional food ingredients. Full article

Substantial agro-industrial waste is generated by the food industry, including pistachio green hulls (PGH), which can constitute 40% to 60% of the fresh fruit weight. This by-product contains bioactive functional components, especially phenolic compounds (PCs). An overview of research focused on PCs extracted from PGH is presented, highlighting their chemical composition, extraction methods, compound identification, and antioxidant and antibacterial activities. Extraction techniques such as ultrasound, microwave-assisted extraction, and solid-state fermentation are utilized, with mild organic solvents like water, ethanol, methanol, or their mixtures employed. The quantification of PCs is commonly performed using the Folin–Ciocalteu assay, HCl-Butanol technique, and aluminum chloride colorimetric assays. Furthermore, identification of compounds is generally accomplished through high-performance liquid chromatography (HPLC) or gas chromatography (GC), often coupled with mass spectrometry or photodiode-array detectors to enhance accuracy and reliability. Gallic acid, kaempferol, quercetin, cyanidin, and catechin are the main PCs identified, with their antioxidant activity validated by ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)), DPPH (2,2-diphenyl-1-picrylhydrazyl), and FRAP (ferric-reducing antioxidant power) assays. Antibacterial effectiveness has been demonstrated against bacteria using disk diffusion and minimum inhibitory concentration methods. These findings indicate potential uses of PGH by-products in the food, cosmetic, and pharmaceutical industries, contributing to a circular economy and enhancing agro-industrial waste management. Full article

Rapeseed pomace, a by-product of oil processing, is a rich source of bioactive compounds with potential antioxidant properties. This study aimed to evaluate the tocopherol content and antioxidant capacity of rapeseed pomace in comparison with commonly used edible oils. Chromatographic analysis using high-performance liquid chromatography with electrochemical detection (HPLC–ED), spectrophotometric assays including 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and the Folin–Ciocalteu method, as well as electrochemical approaches such as cyclic voltammetry (CV) and differential pulse voltammetry (DPV), were applied to provide a comprehensive assessment. Rapeseed pomace exhibited the highest total tocopherol concentration (>70 mg/100 g) and strong antioxidant activity confirmed across all assays. Significant correlations (r ≈ 0.9) between spectrophotometric and electrochemical results demonstrated the reliability of the applied techniques. In addition, methanol extraction was applied as an alternative to saponification, providing a straightforward approach for tocopherol determination. The findings highlight rapeseed pomace as a valuable natural antioxidant source and support the applicability of electrochemical methods for the evaluation of edible oils. Full article

Wine lees, a winemaking by-product, have high potential for reuse due to their significant phenolic content and antioxidant capacity. To preserve their composition and enhance their feasibility for incorporation into food products, this study evaluated the effects of oven drying (40 °C) and freeze-drying on the physicochemical and nutritional characteristics of malolactic lees, as well as the impact of the storage time. Samples were analyzed at 0, 45, and 90 days of storage at 25 °C under light exposure conditions. Total phenolic content was determined by Folin–Ciocalteu, antioxidant activity by DPPH and FRAP assays, and phenolic groups by HPLC-DAD-FD. Both methods preserved a high protein content (~20%), with 44.66% essential amino acids and an essential amino acid index of 1.55, indicating high-quality proteins. The freeze-dried lees showed a higher phenolic content (77.92 mg GAE/g), whereas the oven-dried lees exhibited greater antioxidant activity, likely due to the formation or release of bound phenolic compounds induced by thermal processing. Among the phenolic groups, tannins were the most favored in terms of preservation. Storage time significantly influenced the parameters evaluated, indicating the impact of drying on stability. While freeze-drying better preserved phenolic compounds, oven drying was considered the most suitable option for large-scale application. Full article

Phenolic compounds are regarded as one of the components responsible for olive oil’s functional properties and health benefits. These chemicals act as antioxidants and anti-inflammatories, and prevent chronic diseases. The Folin–Ciocalteu reagent or HPLC procedures are commonly used to determine the concentration of total phenolic compounds in olive oil. The use of ethyl lactate or lactic acid ethyl ester (LAEE) instead of methanol (MeOH) was examined in terms of green chemistry. Six extra virgin olive oils (EVOOs) with phenolic content ranging from 20 to 350 mg/L, were first extracted with 1:4, 2:3, 3:2, 4:1, and 5:0 MeOH or LAEE/water, (v/v), to determine total phenolic content (TPC) and antiradical activity (%RSA) using the Folin–Ciocalteu reagent and DPPH assay, respectively. The concentration of extracted phenolics or extracts’ RSA increased as the water content in the organic solvent mixture decreased. Also, TPC values were greater when extracted with LAEE than MeOH, while the differences were modest. The HPLC profiles of EVOO phenolic extracts produced by 4:1 MeOH or LAEE/water, (v/v), were indistinguishable in principal component analysis. Simplification of the phenolic profile via acid hydrolysis, resulting in increased hydroxytyrosol and tyrosol content liberated from the corresponding bound forms, showed that both organic solvents equally recovered the predominating phenols of the polar fraction. A noted limitation of LAEE extraction is the need for freeze-drying to remove it prior to HPLC analysis of aqueous extracts. Nonetheless, these findings support LAEE as an effective and environmentally friendly alternative to MeOH for EVOO phenolic extraction in both analytical and industrial contexts. Full article

This study explores the valorization of chestnut burrs (Castanea sativa), an abundant agro-industrial residue, as a natural filler for polylactic acid (PLA)-based biocomposites with potential applications in additive manufacturing. PLA/chestnut burr composite filaments were prepared by melt extrusion with filler contents of 2.5%, 5%, 10%, and 15% w/w, and their chemical, thermal, morphological, and mechanical properties were systematically characterized. ATR-FTIR confirmed the absence of major chemical modifications of the PLA matrix. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), the latter performed on both the extruded filaments and the material after fused deposition modeling (FDM) 3D printing, revealed a slight decrease in thermal stability with increasing filler content, coupled with enhanced crystallinity. Mechanical properties analysis showed that the addition of chestnut burrs did not negatively impact the viscoelastic behavior of the filaments. Scanning electron microscopy (SEM) highlighted good filler dispersion up to 5% loading, while higher percentages led to increased surface roughness and microvoids. Importantly, antioxidant activity assays (DPPH, ABTS, FRAP, and Folin–Ciocâlteu) demonstrated that the incorporation of chestnut burr significantly enhanced the radical-scavenging capacity, reducing power, and total phenolic content (TPC) of PLA. These functionalities were preserved, and in some cases amplified, after FDM 3D printing, indicating that the processing conditions did not degrade the bioactive constituents. Overall, chestnut burrs are confirmed as an effective multifunctional filler for PLA, improving its antioxidant activity while maintaining structural and thermal performance, supporting the development of sustainable biocomposites for emerging applications. Full article