Search Results (140)

Quercus acorns have been part of animal or human diets; however, their nutritional potential depends on morphological and chemical characteristics highly influenced by genetic and geographical factors. Research on the Quercus genus has focused on Asian and European species overlooking the American taxa. Therefore, this study aimed to evaluate the morphological and nutritional characteristics, and the content and profile of bioactive compounds of acorns from four populations of the American species Quercus virginiana from the state of Chihuahua, Mexico. Discriminant function analysis showed a well-established group formed by the two southern populations (CH), while the two northern populations were separated into different groups (CJA and CJB). CH populations showed smaller seeds (1.4 g, 2.0 cm length) and higher starch (57–58%), oleic acid (65–70%), phenolic compounds (78–176 mg GAE/g), flavonoids (29–37 mg CE/g), and antioxidant activity (278–282 μmol TE/g). Acorns from the CJA population were the largest (2.3 g, 2.4 cm length) and displayed the highest protein content (7.0%). Acorns from the CJB population showed the highest values for ash (2.2%), sugars (13.8%), palmitic and linoleic acids (19.1%), and condensed tannins (0.26 CE/g). Fourteen polyphenolic compounds were identified: twelve hydrolysable tannins; one hydroxycinnamic acid, and one flavonol. These variations reflected the impact of local climatic and geographic conditions and may influence the potential use of Quercus acorns in sustainable agriculture and food development. Full article

Elaeocarpus sylvestris (Lour.) Poir., an evergreen tree native to East and Southeast Asia, has gained increasing scientific attention owing to its broad pharmacological properties. Traditionally used in East Asian medicine to treat inflammation, fever, and infectious diseases, modern research has revealed diverse bioactivities, including potent antioxidant, anti-inflammatory, antiviral, anticancer, antidiabetic, and immunomodulatory effects. This therapeutic potential is primarily attributed to its rich phytochemical composition, particularly polyphenols such as geraniin, 1,2,3,4,6-penta-O-galloyl-β-D-glucose and quercetin. This review particularly focuses on the chemistry of E. sylvestris, summarizing structurally elucidated compounds, including hydrolysable tannins, flavonoids, and triterpenoids, along with recent insights into the structure–activity relationships that underpin these antiviral, antioxidant, and anticancer activities. Recent studies have demonstrated substantial antiviral efficacy of E. sylvestris extracts and isolated compounds against major human pathogens, including herpesviruses, influenza A virus, and SARS-CoV-2, supported by in silico, in vitro, in vivo, and early-phase clinical evaluations. Its cosmeceutical applications, including antioxidant, skin-whitening, and blue-light protective effects, further highlight its multifunctional potential. To our knowledge, this is the first comprehensive review summarizing the phytochemistry, pharmacological activities, therapeutic potential, and cosmeceutical applications of E. sylvestris. Despite these promising findings, challenges remain in elucidating precise molecular mechanisms, pharmacokinetics, and clinical validation. This review identifies current research gaps and future directions necessary to advance E. sylvestris as a scientifically validated natural therapeutic resource. Full article

The use of oenological additives is an emerging trend in winemaking aimed at improving technological properties. Recent studies suggest that these additives may also influence aroma persistence after wine consumption by modulating the retention of aroma compounds in the oral cavity. The aim of this study was to evaluate the effect of three commercial oenological additives, hydrolysable tannins (gallotannin and ellagitannin) and yeast mannoproteins, on the oral aroma retention of selected aroma compounds in red and white wines. Eight aromatised wines were prepared, including three red and three white wines with additives and two control wines without additives. Thirty-eight volunteers rinsed with each wine following the Spit-Off Odorant Measurement (SOOM) procedure. Oral aroma retention was calculated by comparing aroma levels in expectorated samples with those in wines prior to oral processing. Results showed that additive type significantly affected oral aroma retention (p < 0.05), depending on both the aroma compound and the wine matrix. In red wines, tannins increased the oral retention of most aroma compounds (5–20%), whereas in white wines, tannins reduced aroma retention. Mannoproteins enhanced oral aroma retention (5–40%) in both wine types. These results highlight the role of interactions between oenological additives, aroma compounds, and the wine matrix in modulating oral aroma retention. Full article

Corn germ meal contains high-quality protein with the potential of producing bioactive peptides. This study aimed to improve the peptide yield and bioactivity of protein hydrolysates from corn germ meal via thermal-alkaline treatment and solid-state fermentation. Corn germ meal was subjected to thermal-alkaline treatment, and the processing conditions were screened. The material obtained under the optimal conditions was then used for solid-state fermentation. The optimal conditions for thermal-alkaline treatment were 100 meshes, a treatment temperature of 100 °C, an alkali concentration of 1.3%, a treatment duration of 30 min, and a water addition of 120%. The protein digestibility of corn germ meal under optimal conditions improved by 86.28%. The combined treatment of thermal-alkaline treatment and solid-state fermentation significantly altered the chemical composition and structural characteristics of corn germ meal, thereby influencing the solubility and hydrolyzability of its proteins. This approach effectively increased the protein yield (≤37.89%) and peptide yield in protein hydrolysates (≤26.01%) of corn germ meal, consequently enhancing the antioxidant activity and angiotensin I-converting enzyme (ACE) inhibitory activity of protein hydrolysates. Furthermore, the treatment altered amino acid composition in the meal material and effectively degraded anti-nutritional factors such as phytic acid and tannin and improved the comprehensive utilization of corn germ meal. Full article

This study aims to evaluate the interspecific variation in polyphenolic profiles and biological activities of acorn flours from three native Tunisian Quercus L. species (Q. ilex L., Q. suber L., and Q. canariensis Willd.). Q. canariensis extracts are the richest in total phenolic, flavonoid and hydrolysable tannin contents. Six phenolic compounds were identified by HPLC-DAD analysis. Chlorogenic acid was the dominant compound in Q. canariensis and Q. ilex acorns. Whereas in Q. suber, caffeic acid was the main component and, along with trans-ferulic acid, was exclusive to this species. Hyperoside was notably identified in Q. canariensis. The UHPLC-DAD-MS analysis of hydrolysable tannins revealed twelve compounds. Acorns of Q. canariensis and Q. suber were dominated by ellagitannins, whereas Q. ilex contained mainly gallotannins. To our knowledge, these compounds are identified for the first time in Tunisian acorns. Q. canariensis exhibited the strongest antioxidant potential with DPPH, ABTS and FRAP assays, as well as the highest antibiofilm and anti-α-amylase activities. All extracts inhibited ATCC pathogenic bacterial strains while largely sparing the beneficial probiotic Limosilactobacillus fermentum. This result indicates a selective antibacterial effect not previously reported for Quercus acorns. Q. canariensis may represent a potential source of functional food ingredient, nutraceuticals, and pharmaceuticals, which remains to be confirmed through in vivo investigations. Full article

This study investigated gluten- and lactose-free cookies enriched with pomegranate seed flour (PSF, 5 and 10% w/w), a sustainable by-product of juice processing. LC-ESI/HRMS/MS analysis of PSF identified 36 bioactive compounds, mainly flavonoids, phenolic acids, hydrolysable tannins, and polar lipids. PSF incorporation significantly affected colour and texture, increasing friability, as evidenced by a reduction in breaking force from 35.37 N in the control cookie to 21.72 N in cookies enriched with 10% PSF, while maintaining good sensory acceptability. Total phenol (≈1.60–1.82 mg GAE/g) and flavonoid contents were only slightly affected by PSF addition; however, antioxidant activity markedly increased, with FRAP values rising from 55.8 to 67.82 μM Fe (II)/g and DPPH IC₅₀ values decreasing from 31.38 to 12.72 μg/mL in the 10% PSF-enriched cookies. The enriched cookies inhibited pancreatic lipase, α-amylase, and α-glucosidase in a clear concentration-dependent manner and showed a reduced predicted glycaemic index (pGI 46.80 vs. 50.08 in the control). Multivariate analysis confirmed a clear dose-dependent effect of PSF on functional, textural, and sensory properties. Overall, pomegranate seed flour proved to be an effective upcycled ingredient for enhancing the functional profile of gluten- and lactose-free bakery products. Further studies using digestion models and in vivo or clinical approaches are needed to clarify the nutritional relevance and health effects of PSF-enriched foods. Full article

Tannins are known for their ability to modify digestion and reduce CH₄ emissions in ruminants. Novel forages able to tolerate water deficits often contain low-to-moderate levels of dietary tannins. The aim of the study was to compare the effect of tannic acid (hydrolysable tannin, HT) and Tannivin (quebracho, condensed tannins, CTs) added to a total mixed ration at a concentration of 2.5% on rumen fermentation over time using in vitro methods. The substrates were incubated with buffered rumen fluid at 39 °C for 0, 3, 6, 12, 24, and 48 h to study dry matter (DM) degradability, tannin disappearance, utilizable protein (uCP), and rumen fermentation parameters. In parallel, gas production was measured using the ANKOM-RF Gas Production System. Gas composition was determined after 24 and 48 h of incubation. DM degradability was influenced by the incubation time (p < 0.001), reaching approximately 50% after 48 h, with a similar course of degradability for both tannin types. Tannin disappearance was significantly influenced by the type of tannins and the incubation time (both p < 0.001), reaching 50% in HTs and 39% in CTs within the first 6 h of fermentation. Production of individual and total VFA and uCP increased during incubation (p < 0.001) but were not influenced by the tannin type. However, the formation of uCP was relatively stable over time. Ammonia-N production increased during the first 12 h of fermentation with both tannin types and the increase continued with HTs (p < 0.001). Gas and methane production increased during fermentation and the increase was more substantial in HTs (p < 0.001). Our results suggest that at moderate concentrations, tannins mainly affect protein metabolism, with a minor effect on rumen fermentation. Full article

The European chestnut (Castanea sativa Mill.) industry generates substantial amounts of underutilized biomass, including shells, leaves, and spiny burs. Distinguishing itself from existing literature, this review presents a novel, integrated life-science analysis that redefines these by-products as a complementary ‘bioactive triad’, ranging from metabolic regulators to anti-virulence agents, rather than interchangeable sources of polyphenols. Although traditionally discarded, these by-products are rich sources of polyphenols, ellagitannins, and flavonoids, with promising potential for nutraceutical, cosmetic, and pharmaceutical applications. This review examines recent advances in the valorization of chestnut by-products, focusing on extraction strategies, chemical profiles, and biological activities. Shell valorization has increasingly shifted toward green extraction technologies, such as subcritical water extraction and deep eutectic solvents, which strongly influence bioactive recovery and composition. Chestnut leaves emerge as a sustainable resource enriched in hydrolysable tannins with anti-inflammatory and quorum sensing-inhibitory properties, particularly relevant for dermatological applications. Spiny burs, often the most phenolic-rich fraction, display marked antioxidant activity and the ability to potentiate conventional antibiotics against pathogens such as Helicobacter pylori. Despite these promising features, major challenges remain, including cultivar-dependent chemical variability, the predominance of in vitro evidence, and safety concerns related to the accumulation of potentially toxic elements. Overall, while chestnut by-products represent valuable resources within circular bioeconomy frameworks, their successful industrial and practical translation will require standardized extraction protocols, robust bioavailability assessments, and well-designed in vivo and clinical studies to ensure safety and efficacy. Full article

Background: Agri-food by-products are increasingly recognized as valuable sources of tannins, whose antioxidant properties represent the primary driver of their biological activity across human and animal health. The strong redox-modulating capacity of condensed and hydrolysable tannins provides a unifying mechanistic explanation for their effects on inflammation, metabolism, gut integrity and neuroprotection. Methods: This narrative review synthesizes evidence obtained through a structured literature search across major databases, selecting studies that investigated antioxidant mechanisms of tannin-rich matrices from plant- and processing-derived residues. Results: Condensed tannins, particularly proanthocyanidins, consistently display potent antioxidant activity through radical scavenging, metal chelation and activation of endogenous defenses, thereby underpinning their anti-inflammatory, anti-ischemic, neuroprotective and metabolic actions. Hydrolysable tannins similarly exert strong antioxidative effects that support antimicrobial activity, enzyme modulation and protection against neuroinflammation. In animals, the antioxidant capacity of tannins translates into improved oxidative balance, enhanced immune status, reduced tissue damage, better feed efficiency and mitigation of oxidative stress-linked methane emission pathways. Conclusions: Antioxidant activity emerges as the central, cross-species mechanism through which tannins mediate diverse health benefits. Tannin-rich agri-food by-products therefore represent promising sustainable antioxidant resources, although their efficacy remains influenced by tannin class, degree of polymerization and dosage, warranting further mechanistic and translational research. Full article

Hydrolysable tannins (HTs) are polyphenolic compounds extracted from plants consisting of a sugar core, esterified with phenolic acids, such as gallic or ellagic acid. These phenolic acids are responsible for their well-known antioxidant, anti-tumor, antimicrobial, and anti-inflammatory properties. This study investigated the potential protective role of HTs against bisphenol A (BPA), an environmental pollutant known to have toxic effects. Zebrafish embryos were exposed to BPA at 25.0 µM alone and in combination with HTs at 5.0, 10.0, and 20.0 µgL⁻¹ for 72 h. The results showed that HTs at 20.0 µgL⁻¹ improved hatching and heart rate affected by BPA and reduced the phenotypic alterations caused by BPA. In addition, molecular analysis of genes involved in development showed that the down-regulation of cd63, zhe1, klf4, hand2, sox9b, and gata4 genes in the BPA group were improved with HTs 20.0 µgL⁻¹. Furthermore, HTs were able to reduce the increased lipid content caused by exposure to BPA. These results demonstrate that HTs have a protective effect on the development of zebrafish exposed to BPA, suggesting that they could potentially exert protective effects in response to other environmental stressors. 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

Medicinal plants are widely used in traditional medicine because of their bioactive compounds with therapeutic potential. The semidesert Mexican species Flourensia cernua, Artemisia ludoviciana, and Phoradendron californicum have been traditionally employed as infusions for gastrointestinal disorders. In this study, chemical composition, infusion extraction, phytochemical profiling, antioxidant capacity, and antiparasitic and antibacterial activity were evaluated. The extracts were characterized via HPLC–MS, encapsulated in agar–agar beads, and subjected to in vitro simulated digestion. A. ludoviciana presented the highest content of hydrolysable and condensed tannins (5473.33 ± 305.5 mg GAE/100 g; 959.58 ± 14.6 mg CE/100 g, respectively). F. cernua presented the highest flavonoid concentration (582.67 ± 16.90 mg CE/100 g). The highest antioxidant activity was observed in P. californicum (IC₅₀ 74.18 ± 18.43 μg TE/mL in DPPH; IC₅₀ 333.38 ± 56.36 μg TE/mL in ABTS). In terms of antiparasitic effects, A. ludoviciana extracts presented the lowest IC₅₀ value (0.51 ± 0.01 mg/mL), indicating the highest antiparasitic activity. Antibacterial assays revealed that F. cernua had the greatest inhibitory effect on E. coli (79.60%) and S. aureus (78.40%). Encapsulation preserved extract integrity, although simulated digestion resulted in limited compound release, with hydrolysable tannins being the most released. Overall, P. californicum presented the strongest antioxidant response, and encapsulation was confirmed as an effective strategy to preserve extract integrity. Full article

Potentilla erecta (L.) Raeusch. is a widely used medicinal species valued for its astringent, anti-inflammatory, and antimicrobial effects. This study examined the variation in hydrolysable tannin and flavonoid content in rhizomes of wild-growing populations collected along an elevational gradient in the Ukrainian Carpathians (180–2020 m above sea level). Rhizomes from fifteen populations were analyzed using pharmacopoeial methods, including thin-layer chromatography for tannins and spectrophotometry for flavonoids. Tannin levels ranged from 15.57% to 31.82%, while flavonoid contents varied between 0.23% and 0.40%, expressed as a percentage of dry weight. Both metabolites showed a strong positive correlation with altitude (r = 0.88 for tannins; r = 0.84 for flavonoids), indicating a clear influence of elevation on their accumulation. The highest concentrations were consistently found in high-mountain populations. These results suggest that environmental factors associated with increasing elevation, such as reduced temperature and enhanced ultraviolet radiation, play a significant role in shaping the phytochemical profile of P. erecta. The study contributes to the understanding of altitudinal effects on secondary metabolite accumulation in mountain plants and provides a basis for further ecological and pharmacological-oriented research related to this species. Full article

This study examined the effects of alfalfa silage versus alfalfa hay in a total mixed ration (TMR) on milk yield, rumen fermentation, and nutrient digestibility in dairy cows. Hydrolyzed tannins (HT) were supplemented individually to assess changes. Thirty-two multiparous Holstein cows (DIM: 94 ± 8 d; milk yield: 41 ± 2 kg) were assigned to four treatments in a 2 × 2 factorial design: basal diet (alfalfa hay, H, or alfalfa silage, S) and additive (control, C, or 100 g/d HT, T). Production performance, rumen fermentation, nutrient digestibility, and blood metabolites were evaluated. Compared with group H, group S had a 0.16% higher milk protein percentage and significantly higher fat-corrected milk yield, milk fat percentage, fat-to-protein ratio, total solids, and milk urea nitrogen. After feeding, the ST group had increased ruminal pH. HT supplementation significantly decreased ruminal NH₃-N levels (p < 0.05) and increased microbial crude protein (MCP) content (p < 0.05). Group H showed no significant changes, and the effects of HT were less evident in hay-fed cows than in silage-fed cows. In summary, alfalfa silage feeding increased ruminal microbial populations, while HT supplementation mitigated the post-feeding decline in ruminal pH. Considering the relatively small sample size (n = 32), the results should be viewed as indicative rather than conclusive, and future studies with larger cohorts will be valuable to confirm and extend these findings. Full article

In recent years, bifunctional ingredients extracted and utilized from waste by-products as raw materials have received significant attention in the food production process. Previous studies have found that bovine livers possess both antioxidant and emulsifying potential; therefore, enhancing these dual properties is a current research focus. In this study, three different types of polyphenols (epigallocatechin gallate [EGCG], gallic acid [GA] and tannin [TA]) provide a reference on how to achieve better complexation of polyphenols with bovine liver hydrolysates (BLHs). Based on the molecular weight results, it was shown that the bovine liver peptides bind to polyphenols to form complexes with higher molecular weights. Furthermore, the binding affinities among the three complexes were as follows: TA > EGCG > GA. The emulsions stabilized by the coupling compounds contained more homogeneous and dense droplets (optical microscopy). Both the antioxidant properties and the emulsifying activity of all complexes were superior to those of bovine liver hydrolysates (BLHs) (p < 0.05), confirming synergistic effects that either flavonoids, phenolic acids or tannins possess with bovine liver hydrolysates. This combination provides an effective strategy for developing novel foods with specific functions. Full article