Tannins in Food: Insights into the Molecular Perception of Astringency and Bitter Taste

Enhancement of rosehip bioactive compounds by cold plasma pretreatment and application of its extract as a functional ingredient in ketchup

The effect of cold plasma (CP) was investigated on rosehip characterization for 1,2.5, and 5 min. All of the samples that were treated with CP had higher amounts of total phenolic content (TPC), antioxidant activity, vitamin C, and lycopene compared to the control (P < 0.05). The extract obtained by rosehip pretreated for 1 min had the highest antioxidant activity as well as bioactive compounds (except anthocyanin) and was selected for application in ketchup. Utilizing the CP-treated rosehip extract (RE) in ketchup successfully enhanced TPC (by 1.44 times), flavonoids (by 1.31 times), antioxidant activity (by 1.21 times), carotenoids (by 1.74 times), lycopene (by 1.11 times), vitamin C (by 1.6 times), and anthocyanins (by 2.46 times) compared to the control (P < 0.05). Moreover, the phenolic profile demonstrated that the highest increase belonged to catechin. Therefore, the RE pretreated by CP has the potential to develop a functional ketchup with high bioactive substances.

Tannic acid protects against colitis by regulating the IL17 - NFκB and microbiota - methylation pathways

Tannic acid, a bioactive polyphenol found in various phytogenic foods and medicinal plants, has potential prevention effects on colitis, though more evidence and mechanistic studies are required to substantiate this. In this study, we investigated the effects of different doses from 0 to 3 mg/mL of tannic acid on mice, ultimately selecting a dose of 3 mg/mL for the anti-colitis trial based on growth and intestinal morphology assessments. Using the DSS-induced colitis model, we found that tannic acid may alleviate colitis by inhibiting the IL-17 - NF-κB p65 signaling pathway and modulating epigenetic pathways, particularly methylation modifications. Additionally, tannic acid altered the gut microbiota, increasing the abundances of Prevotella, Eubacterium_siraeum_group, and Enterorhabdus in the colon. Supplementation with Eubacterium siraeum via gavage also inhibited colitis, accompanied by increased folate and methylation regulators in the colon. These findings suggest that tannic acid may inhibit colitis through the suppression of the IL-17 - NF-κB pathway and the enhancement of microbiota-mediated methylation pathways.

Bacterial Degradation of Antinutrients in Foods: The Genomic Insight

Antinutrients, also known as anti-nutritional factors (ANFs), are compounds found in many plant-based foods that can limit the bioavailability of nutrients or can act as precursors to toxic substances. ANFs have controversial effects on human health, depending mainly on their concentration. While the positive effects of these compounds are well documented, the dangers they pose and the approaches to avoid them have not been discussed to the same extent. There is no dispute that many ANFs negatively alter the absorption of vitamins, minerals, and proteins in addition to inhibiting some enzyme activities, thus negatively affecting the bioavailability of nutrients in the human body. This review discusses the chemical properties, plant bioavailability, and deleterious effects of anti-minerals (phytates and oxalates), glycosides (cyanogenic glycosides and saponins), polyphenols (tannins), and proteinaceous ANFs (enzyme inhibitors and lectins). The focus of this study is on the possibility of controlling the amount of ANF in food through fermentation. An overview of the most common biochemical pathways for their microbial reduction is provided, showing the genetic basis of these phenomena, including the active enzymes, the optimal conditions of action, and some data on the regulation of their synthesis.

Protective Effect of Polyphenolic Extracts from Hippophae rhamnoides L. and Reynoutria japonica Houtt. on Erythrocyte Membrane

Sea buckthorn and Japanese knotweed are known in many traditional medicine systems to be a great source of bioactive substances. This research aims to compare the bioactivity and protective effects of the phenolic extracts of leaves from sea buckthorn and roots and leaves from the Japanese knotweed on erythrocytes. The polyphenol composition of the extract was analyzed using UPLC-PDA-ESI-MS/MS. The extracts' toxicity and impact on the erythrocytes' osmotic fragility were measured spectrophotometrically. The antioxidant activity was determined based on the inhibition of oxidation of erythrocytes and their membrane induced by 2,2'-Azobis(2-methylpropionamidine) dihydrochloride (AAPH),measured spectrophotometrically and using fluorimetry. To find the possible mechanism of the extracts' action, extract-modified cells were observed under a microscope, and the potential localization of the extract's phytochemical composition was checked using fluorescent probes. The results showed that the used extracts are not toxic to erythrocytes, increase their osmotic resistance, and successfully protect them against free radicals. Extract components localize on the outer part of the membrane, where they can scavenge the free radicals from the environment. Altogether, the presented extracts can greatly protect living organisms against free radicals and can be used to support the treatment of diseases caused by excess free radicals.

Oral Astringency in Plant Proteins: An Underestimated Issue in Formulating Next-Generation Plant-Based Foods

Ensuring the supply of affordable, palatable, healthy, and sustainable nutrients to feed the growing population without transgressing the planetary boundaries remains a key challenge in the food science community. A dietary transition toward low-emission, plant-based foods, with less reliance on animal agriculture, is advocated for sustainability, health, and ethical reasons. A major hurdle for mainstream adoption of plant-based foods is their poor sensorial performance, such as nonjuicy and astringent textures as well as various off-flavors. This review presents the current understanding of astringency and oral friction of plant-based foods. It focuses on plant proteins and their application in plant-based meat and dairy analogs. In addition, the latest advances in the quantitative characterization of astringency using tribology, electrochemistry, and cellular tools are covered. Finally, we examine factors influencing astringency and propose easy-to-implement colloidal strategies that may mitigate astringency issues, thereby underpinning the design of the next generation of sustainable and pleasurable plant-based foods.

Stability and Biaxial Behavior of Fresh Cheese Coated with Nanoliposomes Encapsulating Grape Seed Tannins and Polysaccharides Using Immersion and Spray Methods

In the food industry context, where fresh cheese stands out as a highly perishable product with a short shelf life, this study aimed to extend its preservation through multi-layer edible coatings. The overall objective was to analyze the biaxial behavior and texture of fresh cheese coated with nanoliposomes encapsulating grape seed tannins (NTs) and polysaccharides (hydroxypropyl methylcellulose; HPMC and kappa carrageenan; KC) using immersion and spray methods, establishing comparisons with uncoated cheeses and commercial samples, including an accelerated shelf-life study. NT, HPMC, and KC were employed as primary components in the multi-layer edible coatings, which were applied through immersion and spray. The results revealed significant improvements, such as a 20% reduction in weight loss and increased stability against oxidation, evidenced by a 30% lower peroxide index than the uncoated samples. These findings underscore the effectiveness of edible coatings in enhancing the quality and extending the shelf life of fresh cheese, highlighting the innovative application of nanoliposomes and polysaccharide blends and the relevance of applying this strategy in the food industry. In conclusion, this study provides a promising perspective for developing dairy products with improved properties, opening opportunities to meet market demands and enhance consumer acceptance.

Antibacterial activities of Miang extracts against selected pathogens and the potential of the tannin-free extracts in the growth inhibition of Streptococcus mutans

Bacterial pathogens have remained a major public health concern for several decades. This study investigated the antibacterial activities of Miang extracts (at non-neutral and neutral pH) against Bacillus cereus TISTR 747, Escherichia coli ATCC 22595, Salmonella enterica serovar Typhimurium TISTR 292 and Streptococcus mutans DMST 18777. The potential of Polyvinylpolypyrrolidone (PVPP)-precipitated tannin-free Miang extracts in growth-inhibition of the cariogenic Streptococcus mutans DMST 18777 and its biofilms was also evaluated. The tannin-rich fermented extracts had the best bacterial growth inhibition against S. mutans DMST 18777 with an MIC of 0.29 and 0.72 mg/mL for nonfilamentous fungi (NFP) Miang and filamentous-fungi-processed (FFP) Miang respectively. This observed anti-streptococcal activity still remained after PVPP-mediated precipitation of bioactive tannins especially, in NFP and FFP Miang. Characterization of the PVPP-treated extracts using High performance liquid chromatography quadrupole-time of flight-mass spectrometry (HPLC-QToF-MS) analysis, also offered an insight into probable compound classes responsible for the activities. In addition, Crystal violet-staining also showed better IC50 values for NFP Miang (4.30 ± 0.66 mg/mL) and FFP Miang (12.73 ± 0.11 mg/mL) against S. mutans DMST 18777 biofilms in vitro. Homology modeling and molecular docking analysis using HPLC-MS identified ligands in tannin-free Miang supernatants, was performed against modelled S. mutans DMST 18777 sortase A enzyme. The in silico analysis suggested that the inhibition by NFP and FFP Miang might be attributed to the presence of ellagic acid, flavonoid aglycones, and glycosides. Thus, these Miang extracts could be optimized and explored as natural active pharmaceutical ingredients (NAPIs) for applications in oral hygienic products.

Investigation of Health Effects of Major Phenolic Compounds in Foods: Extraction Processes, Analytical Approaches and Applications

The escalating costs of healthcare services and a growing awareness of personal health responsibilities have led individuals to explore natural methods alongside conventional medicines for health improvement and disease prevention. The aging global population is experiencing increased health needs, notably related to conditions like diabetes, heart disease, and hypertension. Lifestyle-related diseases, poor dietary habits, and sedentary lifestyles underscore the importance of foods containing nutrients that can aid in preventing and managing these diseases. Phenolic compounds, a fundamental group of phytochemicals, are prominent in the chemical diversity of the natural world and are abundant in functional foods. Widely distributed in various plant parts, these compounds exhibit important functional and sensory properties, including color, taste, and aroma. Their diverse functionalities, particularly antioxidant activity, play a crucial role in mitigating cellular oxidative stress, potentially reducing damage associated with serious health issues such as cardiovascular disease, neurodegenerative disea23ses, and cancer. Phenolic compounds exist in different forms, some combined with glycosides, impacting their biological effects and absorption. Approximately 8000 polyphenols isolated from plants offer significant potential for natural medicines and nutritional supplements. Therefore, their extraction process and selective and sensitive food determination are very important. This review focuses on the extraction processes, analytical methods, and health effects of major phenolic compounds in foods. The examination encompasses a comprehensive analysis of analytical approaches and their applications in elucidating the presence and impact of these compounds on human health.

Condensed tannins-Their content in plant foods, changes during processing, antioxidant and biological activities

Condensed tannins are considered nutritionally undesirable, because they precipitate proteins, inhibit digestive enzymes, and can affect the absorption of vitamins and minerals. From the consumer's point of view, they impart astringency to foods. Yet, they are viewed as a double-edged sword, since they possess antioxidant and anti-inflammatory activities. Intake of a small quantity of the right kind of tannins may in fact be beneficial to human health. This chapter reports on the chemical structure of condensed tannins, their content in plants and food of plant origin, how they are extracted, and methods for their determination. A description of the effects of processing on condensed tannins is discussed and includes soaking, dehulling, thermal processing (i.e., cooking, boiling, autoclaving, extrusion), and germination. The astringency of condensed tannins is described in relation to their interactions with proteins. Finally, details about the biological properties of condensed tannins, including their antimicrobial, anti-inflammatory, anticancer, anti-diabetic, and anti-obesity activities, are reviewed.

Evaluation of roasting and storage conditions as a strategy to improve the sensory characteristics and shelf life of coffee

Coffee is one of the most consumed products worldwide. Among the varieties of this product, specialty coffee is a type of coffee that has been growing in the world market. This paper aims to assess the effects that the conditions derived from coffee roasting at different altitude levels have on the quality of the product. It was discovered that processing coffee at a higher altitude level yielded a smaller increase in bitterness. This led to a better Specialty Coffee Association (SCA) score in cupping and, consequently, to better preservation of the coffee quality. The storage time affected the aroma by associating roaster aromas with older coffees. Although the assessed origins had the same NIR spectra, differences in peak intensity lead to variations in the flavor and aroma of the coffee. Furthermore, although green beans prolong quality allowing a SCA score of 84.73 ± 2.81 after 4 months of storage, roasted coffee at higher altitudes could also maintain the quality between production and consumption (SCA score of 80.22 ± 0.91 after 2 months). Finally, this research found that the instrumental equipment helped to find minor changes in the sensorial profile, and with these changes correlated with the sensorial panel, the best conditions to preserve coffee quality were found.

Procyanidins and sensory nutrition; do procyanidins modulate homeostasis via astringent taste receptors?

Long-term intake of procyanidins has been suggested to reduce the risk of cardiovascular disease, dementia, and sensory function decline associated with aging. However, most of the ingested procyanidins are not absorbed and are excreted in the feces, so the mechanism of their beneficial impact is unknown. Procyanidins are the components of astringency in plant foods and their stimulation appears to be directly transmitted to the central nervous system via sensory nerves. Recent attention has been focused on the taste receptors expressed in the extra-oral gastrointestinal tract may regulate homeostasis via the neuroendocrine system. In this paper, we have reviewed recent findings on the relationship between the astringency of procyanidins and their bioregulatory effects.

Interindividual differences in aronia juice tolerability linked to gut microbiome and metabolome changes-secondary analysis of a randomized placebo-controlled parallel intervention trial

BACKGROUND

Aronia melanocarpa is a berry rich in polyphenols known for health benefits. However, the bioavailability of polyphenols has been questioned, and the individual taste acceptance of the fruit with its specific flavor varies. We recently observed substantial differences in the tolerability of aronia juice among healthy females, with half of the individuals tolerating aronia juice without complaints. Given the importance of the gut microbiome in food digestion, we investigated in this secondary analysis of the randomized placebo-controlled parallel intervention study (ClinicalTrials.gov registration: NCT05432362) if aronia juice tolerability was associated with changes in intestinal microbiota and bacterial metabolites, seeking for potential mechanistic insights into the impact on aronia polyphenol tolerance and metabolic outcomes.

RESULTS

Forty females were enrolled for this 6-week trial, receiving either 100 ml natural aronia juice (verum, V) twice daily or a polyphenol-free placebo (P) with a similar nutritional profile, followed by a 6-week washout. Within V, individuals were categorized into those who tolerated the juice well (Vt) or reported complaints (Vc). The gut microbiome diversity, as analyzed by 16S rRNA gene-based next-generation sequencing, remained unaltered in Vc but changed significantly in Vt. A MICOM-based flux balance analysis revealed pronounced differences in the 40 most predictive metabolites post-intervention. In Vc carbon-dioxide, ammonium and nine O-glycans were predicted due to a shift in microbial composition, while in Vt six bile acids were the most likely microbiota-derived metabolites. NMR metabolomics of plasma confirmed increased lipoprotein subclasses (LDL, VLDL) post-intervention, reverting after wash out. Stool samples maintained a stable metabolic profile.

CONCLUSION

In linking aronia polyphenol tolerance to gut microbiota-derived metabolites, our study explores adaptive processes affecting lipoprotein profiles during high polyphenol ingestion in Vt and examines effects on mucosal gut health in response to intolerance to high polyphenol intake in Vc. Our results underpin the importance of individualized hormetic dosing for beneficial polyphenol effects, demonstrate dynamic gut microbiome responses to aronia juice, and emphasize personalized responses in polyphenol interventions.

Bioactive Components of Areca Nut: An Overview of Their Positive Impacts Targeting Different Organs

Areca catechu L. is a widely cultivated tropical crop in Southeast Asia, and its fruit, areca nut, has been consumed as a traditional Chinese medicinal material for more than 10,000 years, although it has recently attracted widespread attention due to potential hazards. Areca nut holds a significant position in traditional medicine in many areas and ranks first among the four southern medicines in China. Numerous bioactive compounds have been identified in areca nuts, including alkaloids, polyphenols, polysaccharides, and fatty acids, which exhibit diverse bioactive functions, such as anti-bacterial, deworming, anti-viral, anti-oxidant, anti-inflammatory, and anti-tumor effects. Furthermore, they also display beneficial impacts targeting the nervous, digestive, and endocrine systems. This review summarizes the pharmacological functions and underlying mechanisms of the bioactive ingredients in areca nut. This helps to ascertain the beneficial components of areca nut, discover its medicinal potential, and guide the utilization of the areca nut.

Sensory Nutrition and Bitterness and Astringency of Polyphenols

Recent studies have demonstrated that the interaction of dietary constituents with taste and olfactory receptors and nociceptors expressed in the oral cavity, nasal cavity and gastrointestinal tract regulate homeostasis through activation of the neuroendocrine system. Polyphenols, of which 8000 have been identified to date, represent the greatest diversity of secondary metabolites in plants, most of which are bitter and some of them astringent. Epidemiological studies have shown that polyphenol intake contributes to maintaining and improving cardiovascular, cognitive and sensory health. However, because polyphenols have very low bioavailability, the mechanisms of their beneficial effects are unknown. In this review, we focused on the taste of polyphenols from the perspective of sensory nutrition, summarized the results of previous studies on their relationship with bioregulation and discussed their future potential.

Tannic acid adsorption properties of cellulose nanocrystalline/fish swim bladder gelatin composite sponge

Foods and beverages with excessive tannins acid (TA) content taste astringent and bitter. The overconsumption of TA could result in nutritional and digestive problems. In this study, the cellulose nanocrystals (CNC)/fish swim bladder gelatin (FG) composite sponge was prepared with glutaraldehyde as a crosslinking agent. The TA adsorption performance of the sponge was discussed. The freeze-dried CNC/FG composite sponge had a porous network structure. CNC was combined into the FG matrix as a reinforcing phase. The mechanical strength, thermal stability, and swelling properties of the composite sponge were improved with the addition of an appropriate amount of CNC. Although CNC decreased the porosity of composite sponge, the increase in active adsorption sites resulted in an overall positive effect on its TA adsorption properties. Under the optimal adsorption conditions, the TA removal rate of 1.0 % CNC composites reached 80.4 %. Furthermore, the sponge retained a TA removal rate of 54 % after five cycles of adsorption and desorption using 50 % ethanol. The results demonstrated that CNC/FG composite sponge has application potential in the field of adsorption materials for TA.

Physicochemical Properties of Nanoliposomes Encapsulating Grape Seed Tannins Formed with Ultrasound Cycles

Grape seeds are an excellent source of flavonoids and tannins with powerful antioxidant properties. However, the astringency of tannins limits their direct incorporation into food. To overcome this challenge, we investigated the encapsulation of grape seed tannins within nanoliposomes formed by ultrasound cycling. We characterized the nanoliposomes' physicochemical properties, including encapsulation efficiency, antioxidant activity, stability, microstructure, and rheological properties. Our findings reveal that the nanoliposomes exhibited excellent stability under refrigerated conditions for up to 90 days with a mean particle size of 228 ± 26 nm, a polydispersity index of 0.598 ± 0.087, and a zeta potential of -41.6 ± 1.30 mV, maintaining a spherical multilamellar microstructure. Moreover, they displayed high antioxidant activity, with encapsulation efficiencies of 79% for epicatechin and 90% for catechin. This innovative approach demonstrates the potential of using ultrasound-assisted nanoliposome encapsulation to directly incorporate grape seed tannins into food matrices, providing a sustainable and efficient method for enhancing their bioavailability and functionality.

Development of a cell-based quaternary system to unveil the effect of pectic polysaccharides on oral astringency

Phenolic compounds are responsible for food unpleasant taste properties, including astringency, due to their ability to interact with salivary proteins and oral constituents. Astringency is a crucial attribute for consumer's acceptability. To fulfill the demand for both healthy and tasty food, polysaccharides raise as a good alternative to modulate astringency. In this work, a cell-based quaternary system was developed to evaluate the ability of polysaccharides to reduce the interaction between two classes of hydrolysable tannins - gallotannins (tannic acid) and ellagitannins (punicalagin) - and oral constituents (cells, salivary proteins and mucosal pellicle). So, pectic polysaccharide fractions isolated from grape skins, imidazole soluble polysaccharides (ISP) and carbonate soluble polysaccharides (CSP), as well as a commercial pectin, were tested. Results showed that the polysaccharide's effect depends on the structural features of the molecules involved. CSP fraction and pectin were the most effective, reducing the interactions between both tannins and the oral constituents, mainly in the complete oral model. The highest uronic acid content and the presence of methyl esterified groups could explain their high reduction ability. For tannic acid, the reduction effect increased along with the galloylation degree, while the interaction of β-punicalagin with the oral constituents was practically inhibited at 3.0 mg.mL-1.

Effects of graded levels of dietary pomegranate peel on methane and nitrogen losses, and metabolic and health indicators in dairy cows

This study aimed to quantify the effects of dietary inclusion of tannin-rich pomegranate peel (PP) on intake, methane and nitrogen (N) losses, and metabolic and health indicators in dairy cows. Four multiparous, late-lactating Brown Swiss dairy cows (796 kg body weight; 29 kg/d of energy corrected milk yield) were randomly allocated to 3 treatments in a randomized cyclic change-over design with 3 periods, each comprising 14 d of adaptation, 7 d of milk, urine, and feces collection, and 2 d of methane measurements. Treatments were formulated using PP that replaced on a dry matter (DM) basis 0% (control), 5%, and 10% of the basal mixed ration (BMR) consisting of corn and grass silage, alfalfa, and concentrate. Gaseous exchange of the cows was determined in open-circuit respiration chambers. Blood samples were collected on d 15 of each period. Individual feed intake as well as feces and urine excretion were quantified, and representative samples were collected for analyses of nutrients and phenol composition. Milk was analyzed for concentrations of fat, protein, lactose, milk urea N, and fatty acids. Total phenols and antioxidant capacity in milk and plasma were determined. In serum, the concentrations of urea and bilirubin as well as the activities of alanine aminotransferase (ALT), aspartate aminotransferase, glutamate dehydrogenase, alkaline phosphatase, and γ-glutamyl transferase were measured. The data were subjected to ANOVA with the Mixed procedure of SAS, with treatment and period as fixed and animal as random effects. The PP and BMR contained 218 and 3.5 g of total extractable tannins per kg DM, respectively, and thereof 203 and 3.3 g of hydrolyzable tannins. Total DM intake, energy corrected milk, and methane emission (total, yield, and intensity) were not affected by PP supplementation. The proportions of C18:2n-6 and C18:3n-3 in milk increased linearly as the amount of PP was increased in the diet. Milk urea N, blood urea N, and urinary N excretion decreased linearly with the increase in dietary PP content. Total phenols and antioxidant capacity in milk and plasma were not affected by the inclusion of PP. The activity of ALT increased in a linear manner with the inclusion of PP. In conclusion, replacing up to 10% of BMR with PP improved milk fatty acid composition and alleviated metabolic and environmental N load. However, the elevated serum ALT activity indicates an onset of liver stress even at 5% PP, requiring the development of adaptation protocols for safe inclusion of PP in ruminant diets.

The challenge of breeding for reduced off-flavor in faba bean ingredients

The growing interest in plant protein sources, such as pulses, is driven by the necessity for sustainable food production and climate change mitigation strategies. Faba bean (Vicia faba L.) is a promising protein crop for temperate climates, owing to its remarkable yield potential (up to 8 tonnes ha-1 in favourable growing conditions) and high protein content (~29% dry matter basis). Nevertheless, the adoption of faba bean protein in plant-based products that aim to resemble animal-derived counterparts is hindered by its distinctive taste and aroma, regarded as "off-flavors". In this review, we propose to introduce off-flavor as a trait in breeding programs by identifying molecules involved in sensory perception and defining key breeding targets. We discuss the role of lipid oxidation in producing volatile and non-volatile compounds responsible for the beany aroma and bitter taste, respectively. We further investigate the contribution of saponin, tannin, and other polyphenols to bitterness and astringency. To develop faba bean varieties with diminished off-flavors, we suggest targeting genes to reduce lipid oxidation, such as lipoxygenases (lox) and fatty acid desaturases (fad), and genes involved in phenylpropanoid and saponin biosynthesis, such as zero-tannin (zt), chalcone isomerase (chi), chalcone synthase (chs), β-amyrin (bas1). Additionally, we address potential challenges, including the need for high-throughput phenotyping and possible limitations that could arise during the genetic improvement process. The breeding approach can facilitate the use of faba bean protein in plant-based food such as meat and dairy analogues more extensively, fostering a transition toward more sustainable and climate-resilient diets.

Unraveling the occasional occurrence of berry astringency in table grape cv. Scarlet Royal: a physiological and transcriptomic analysis

Scarlet Royal, a mid-season ripening table grape, is one of the popular red grape varieties in California. However, its berries develop an undesirable astringent taste under certain conditions. Among the various factors contributing to the degradation of berry attributes, the levels and compositions of polyphenols play a fundamental role in defining berry quality and sensory characteristics. To comprehend the underlying mechanism of astringency development, Scarlet Royal berries with non-astringent attributes at the V7 vineyard were compared to astringent ones at the V9 vineyard. Biochemical analysis revealed that the divergence in berry astringency stemmed from alterations in its polyphenol composition, particularly tannins, during the late ripening stage at the V9 vineyard. Furthermore, transcriptomic profiling of berries positively associated nineteen flavonoid/proanthocyanidins (PAs) structural genes with the accumulation of PAs in V9 berries. The identification of these genes holds significance for table grape genetic improvement programs. At a practical level, the correlation between the taste panel and tannin content revealed a threshold level of tannins causing an astringent taste at approximately 400 mg/L. Additionally, berry astringency at the V9 vineyard was linked to a lower number of clusters and yield during the two study seasons, 2016 and 2017. Furthermore, petiole nutrient analysis at bloom showed differences in nutrient levels between the two vineyards, including higher levels of nitrogen and potassium in V9 vines compared to V7. It's worth noting that V9 berries at harvest displayed a lower level of total soluble solids and higher titratable acidity compared to V7 berries. In conclusion, our results indicate that the accumulation of tannins in berries during the ripening process results in a reduction in their red color intensity but significantly increases the astringency taste, thereby degrading the berry quality attributes. This study also highlights the association of high nitrogen nutrient levels and a lower crop load with berry astringency in table grapes, paving the way for further research in this area.

Adult Ossabaw Pigs Prefer Fermented Sorghum Tea over Isocaloric Sweetened Water

Ossabaw pigs (n = 11; 5-gilts, 6-barrows; age 15.6 ± 0.62 SD months) were exposed to a three-choice preference maze to evaluate preference for fermented sorghum teas (FSTs). After conditioning, pigs were exposed, in four sessions, to choices of white FST, sumac FST, and roasted sumac-FST. Then, pigs were exposed, in three sessions, to choices of deionized H2O (-control; avoidance), isocaloric control (+control; deionized H2O and sucrose), and blended FST (3Tea) (equal portions: white, sumac, and roasted sumac). When tea type was evaluated, no clear preference behaviors for tea type were observed (p > 0.10). When the 3Tea and controls were evaluated, pigs consumed minimal control (p < 0.01;18.0 ± 2.21% SEM), and they consumed great but similar volumes of +control and 3Tea (96.6 and 99.0 ± 2.21% SEM, respectively). Likewise, head-in-bowl duration was the least for -control, but 3Tea was the greatest (p < 0.01; 5.6 and 31.9 ± 1.87% SEM, respectively). Head-in-bowl duration for +control was less than 3Tea (p < 0.01; 27.6 vs. 31.9 ± 1.87% SEM). Exploration duration was the greatest in the area with the -control (p < 0.01; 7.1 ± 1.45% SEM), but 3Tea and +control exploration were not different from each other (1.4 and 3.0 ± 1.45% SEM, respectively). Regardless of tea type, adult pigs show preference for FST, even over +control. Adult pigs likely prefer the complexity of flavors, rather than the sweetness alone.

Role of Anthocyanins in the Interaction between Salivary Mucins and Wine Astringent Compounds

Wine astringency is a very complex sensation whose complete mechanism has not been entirely described. Not only salivary proline-rich proteins (PRPs) are involved in its development; salivary mucins can also play an important role. On the other hand, it has been described that anthocyanins can interact with PRPs, but there is no information about their potential role on the interactions with mucins. In this work, the molecular interactions between salivary mucins (M) and different wine phenolic compounds, such as catechin (C), epicatechin (E) and quercetin 3-β-glucopyranoside (QG), as well as the effect of the anthocyanin malvidin 3-O-glucoside (Mv) on the interactions with mucins, were assessed by isothermal titration calorimetry (ITC). Results showed that the interaction between anthocyanin and mucins is stronger than that of both flavanols analyzed, since the affinity constant values were 10 times higher for anthocyanin than for catechin, the only flavanol showing interaction in binary assay. Moreover, at the concentration at which polyphenols are usually found in wine, flavonols seem not to be involved in the interactions with mucins. These results showed, for the first time, the importance of wine anthocyanins in the mechanisms of astringency involving high-molecular-weight salivary proteins like mucins.

Effects of sprouting duration on the nutrient, functional, and phytochemical properties of tiger nut flour, and the sensory properties of bread made thereof

The influence of sprouting on tiger nut's (TN) nutritional, functional, and phytochemical quality was examined, and the flour used for bread making to evaluate the feasibility as a functional ingredient. TN was sprouted and sampled at 3 days intervals for 12 days, dried and milled into flour and analyzed. Subsequently, 25% of wheat flour (WF) was replaced with the 9 days-sprouted TN flour for bread. Sprouting for 9 days increased the protein content from 9.19 ± 0.04 to 9.79 ± 0.15 g/100 g dry matter (DM), fiber from 6.75 ± 0.16 to 9.27 ± 0.44 g/100 g DM, and ash from 2.34 ± 0.10 to 2.70 ± 0.06 g/100 g DM but decreased fat content from 26.10 ± 0.18 to 23.18 ± 0.43 g/100 g DM and soluble sugar from 33.13 ± 1.25 to 23.75 ± 1.44 °Bx. We observed increases in the polyphenols (94.16 ± 6.43-214.23 ± 6.98 mg GAE/100 g) and ascorbic acid (26.66 ± 0.17-65.13 ± 0.19 mg AE/100 g) and decreases in the cyanogenic glycosides (273.79 ± 0.37-231.54 ± 3.53 mg/100 g) and oxalates (19.04 ± 1.14-5.65 ± 0.93 mg/100 g) contents. Sprouting decreased the particle size and increased the water retention and swelling power of TN flour. WF bread was described as stretchy, sweet, and creamy, whereas sprouted TN bread was brown, nutty, and wheat-like. Consumer acceptance for the sprouted TN bread was comparable to WF bread, showing the possible application in bread making. PRACTICAL APPLICATION: The outcome of the study could help to exploit the nutri-functional and phytochemical benefits of sprouted TN in the baking industry for producing acceptable products. This would enhance the utility of TN for food in regions where TNs grows.

The perception and influencing factors of astringency, and health-promoting effects associated with phytochemicals: A comprehensive review

Astringency as the complex sensory of drying or shrinking can be perceived from natural foods, including abundant phenolic compounds. Up to now, there have been two possible astringency perception mechanisms of phenolic compounds. The first possible mechanism involved chemosensors and mechanosensors and took salivary binding proteins as the premise. Although piecemeal reports about chemosensors, friction mechanosensor's perception mechanisms were absent. There might be another perception way because a part of astringent phenolic compounds also triggered astringency although they could not bind with salivary proteins, however, the specific mechanism was unclear. Structures caused the differences in astringency perception mechanisms and intensities. Except for structures, other influencing factors also changed astringency perception intensity and aimed to decrease it, which probably ignored the health-promoting effects of phenolic compounds. Therefore, we roundly summarized the chemosensor's perception processes of the first mechanism. Meanwhile, we speculated that friction mechanosensor's probably activated Piezo2 ion channel on cell membranes. Phenolic compounds directly binds with oral epithelial cells, activating Piezo2 ion channel probably the another astringency perception mechanism. Except for structure, the increase of pH values, ethanol concentrations, and viscosity not only lowered astringency perception but were beneficial to improve the bioaccessibility and bioavailability of astringent phenolic compounds, which contributed to stronger antioxidant, anti-inflammatory, antiaging and anticancer effects.

Biological and pharmacological aspects of tannins and potential biotechnological applications

Secondary metabolites are divided into three classes: phenolic, terpenoid, and nitrogenous compounds. Phenolic compounds are also known as polyphenols and include tannins, classified as hydrolysable or condensed. Herein, we explored tannins for their ROS reduction characteristics and role in homeostasis. These activities are associated with the numbers and degree of polymerisation of reactive hydroxyl groups present in the phenolic rings of tannins. These characteristics are associated with anti-inflammatory, anti-aging, and anti-proliferative health benefits. Tannins can reduce the risk of cancer and neurodegenerative diseases, such as cardiovascular diseases and Alzheimer's, respectively. These biomolecules may be used as nutraceuticals to maintain good gut microbiota. Industrial applications include providing durability to leather, anti-corrosive properties to metals, and substrates for 3D printing and in bio-based foam manufacture. This review updates regarding tannin-based research and highlights its biological and pharmacological relevance and potential applications.

Investigating wine astringency profiles by characterizing tannin fractions in Cabernet Sauvignon wines and model wines

Contribution of various phenols on wine astringency profiles was far from clear explanations. To effectively describe wine astringency profiles and determined the function of tannins/matrix (pH and ethanol), multiple chemical analyses combined RATA (Rate-all-that-apply) sensory method were applied in Cabernet Sauvignon and model wines. Results showed that polymeric flavanols determined the bulk of wine astringency intensity, oligomeric tannins enriched the smoothness and periodontium astringency, and monomeric phenol enhanced overall astringency intensity through synergistic effect. Astringency balance was effectively quantification, and its potential correlation relationship with epicatechin extension subunit (0.83) and fluorescence peak shift (0.75) cannot be ignored. The astringency profiles of condensed tannins with anthocyanins were enhanced. Low-pH (from 3.8 to 3.0) enhanced astringency by increasing the tannins affinity to proteins, while ethanol (from 10.0 % ∼ 15.0 %) decreased the hydrophobicity bond between tannins-protein interaction. This paper provided new insights to explain wine astringency profiles and a reference for astringency modification during winemaking.

Activation of transient receptor potential channels is involved in reactive oxygen species (ROS)-dependent regulation of blood flow by (-)-epicatechin tetramer cinnamtannin A2

Intervention trials confirmed that blood flow-mediated dilatation increases significantly after intake of astringent (-)-epicatechin (EC) oligomers (procyanidins)-rich foods, but the mechanism remains unclear. We have previously found that procyanidins can activate the sympathetic nervous and subsequently increase blood flow. Here, we examined whether procyanidin-derived reactive oxygen species (ROS) activate transient receptor potential (TRP) channels in gastrointestinal sensory nerves and consequently induce sympathoexcitation. We evaluated the redox properties of EC and its tetramer cinntamtannin A2 (A2) at pH 5 or 7, mimicking plant vacuole or oral cavity/small intestine using a luminescent probe. At pH 5, A2 or EC showed O₂^･- scavenging ability, but they promoted O₂^･- generation at pH 7. We observed blood flow in rat cremaster arterioles using laser Doppler, a single oral dose of 10 µg/kg A2 markedly increased blood flow, while EC showed little activity. This change with A2 was significantly dampened by co-administration of adrenaline blocker, ROS scavenger N-acetyl-L-cysteine (NAC), TRP vanilloid 1, or ankyrin 1 antagonist. We also performed a docking simulation of EC or A2 with the binding site of a typical ligand for each TRP channel and calculated the respective binding affinities. The binding energies were notably higher for A2 than typical ligands, suggesting that A2 is less likely to bind to these sites. ROS produced at neutral pH following the orally administered A2 to the gastrointestinal tract could activate TRP channels, triggering sympathetic hyperactivation and causing hemodynamic changes.

Phyllanthi Fructus: A modal medicinal and food homologous item in quality evaluation

Phyllanthi Fructus is a highly unique medicine and food homologous item, which exhibits distinctive flavor, notable nutritional value, and abundant pharmacological activity. It has enormous potential in the creation of health products and pharmaceuticals. However, due to the unique laws of quality formation and transfer of Phyllanthi Fructus, its appearance, shape, chemical compositions, nutrients, and sensory flavors are frequently greatly influenced by botanical resources, the processing and storage conditions. As a result, the current quality evaluation model is difficult to meet the needs of Phyllanthi Fructus as a medicine and food homologous item in the development of diversified products. This paper constructs the hierarchical utilization mode of Phyllanthi Fructus based on its unique quality formation and transmission laws, explores the quality evaluation model for food-oriented use and medicinal-oriented use, respectively, and systematically describes the quality evaluation idea under diversified application scenarios. This paper aims to serve as a reference for the construction of a quality evaluation model suitable for the medicine and food homologous item of Phyllanthi Fructus.

The Influence of (Poly)phenol Intake in Saliva Proteome: Short- and Medium-Term Effects of Apple

The relationship between salivary proteome and dietary habits was studied in previous works, where a relationship between salivary proteins like cystatins and polyphenol/tannin levels in diet was observed. However, it remains to be elucidated if this association results from an effect of polyphenol-rich food ingestion on saliva composition. The aim of this work was to test the effects of apple intake on the saliva proteome, both in the short and medium term (after 4 days of continuous intake). By incubating saliva samples with apple phenolic-rich extract, protein bands containing α-amylase, S-type cystatins, and proline-rich proteins (PRPs) appeared in the fraction that precipitated, showing the potential of these (poly)phenols to precipitate salivary proteins. Among these, it was salivary cystatins that presented changes in their levels both in the saliva samples collected immediately after apple intake and in the ones collected after 4 days of intake of an extra amount of apple. These results support the thought that intake is reflected in the salivary proteome. The effect of a polyphenol-rich food, like the apple, on salivary cystatin levels is in line with results observed in animal models and, due to the involvement of these proteins in oral food perception, it would be interesting to explore in future studies the effect of these changes on sensory perception and acceptance of polyphenol-rich food.

Metabolome and Transcriptome Integrated Analysis of Mulberry Leaves for Insight into the Formation of Bitter Taste

Mulberry leaves are excellent for health care, confirmed as a 'drug homologous food' by the Ministry of Health, China. The bitter taste of mulberry leaves is one of the main problems that hinders the development of the mulberry food industry. The bitter, unique taste of mulberry leaves is difficult to eliminate by post-processing. In this study, the bitter metabolites in mulberry leaves were identified as flavonoids, phenolic acids, alkaloids, coumarins and L-amino acids by a combined analysis of the metabolome and transcriptome of mulberry leaves. The analysis of the differential metabolites showed that the bitter metabolites were diverse and the sugar metabolites were down-regulated, indicating that the bitter taste of mulberry leaves was a comprehensive reflection of various bitter-related metabolites. Multi-omics analysis showed that the main metabolic pathway related to bitter taste in mulberry leaves was galactose metabolism, indicating that soluble sugar was one of the main factors of bitter taste difference in mulberry leaves. Bitter metabolites play a great role in the medicinal and functional food of mulberry leaves, but the saccharides in mulberry leaves have a great influence on the bitter taste of mulberry. Therefore, we propose to retain bitter metabolites with drug activity in mulberry leaves and increase the content of sugars to improve the bitter taste of mulberry leaves as strategies for mulberry leaf food processing and mulberry breeding for vegetable use.

Mitigation of cashew apple fruits astringency

The cashew apple is a tropical pseudo fruit, with high fiber content, high nutritional value, and therapeutic compositional profile. Consuming cashew apples can help with several health-related problems, such as obesity, stomach ulcers, and gastritis. It has even demonstrated anti-tumor and anti-carcinogenic effects, and its antioxidants can help with wound-healing. Despite such benefits, the cashew apple is frequently considered as waste generated by cashew nut industries, since its commercial applications are restricted by the astringency and poor storability. This astringency is primarily due to the presence of tannins; and a lack of proper, efficient, and economical astringency reduction strategy is accountable for major waste generation. This review compiles pieces of information on the causes of astringency, as well as tannin reduction methods, such as clarification, thermal treatments, microfiltration, and fermentation. These methods aim to either just reduce tannin content or to valorize this by-product in a less-astringent better product. Both routes will eventually help with the better utilization of said organic food waste, which is critical for sustainable development.

Therapeutic Potential of Polyphenols and Other Micronutrients of Marine Origin

Polyphenols are compounds found in various plants and foods, known for their antioxidant and anti-inflammatory properties. Recently, researchers have been exploring the therapeutic potential of marine polyphenols and other minor nutrients that are found in algae, fish and crustaceans. These compounds have unique chemical structures and exhibit diverse biological properties, including anti-inflammatory, antioxidant, antimicrobial and antitumor action. Due to these properties, marine polyphenols are being investigated as possible therapeutic agents for the treatment of a wide variety of conditions, such as cardiovascular disease, diabetes, neurodegenerative diseases and cancer. This review focuses on the therapeutic potential of marine polyphenols and their applications in human health, and also, in marine phenolic classes, the extraction methods, purification techniques and future applications of marine phenolic compounds.

Bitterness quantification and simulated taste mechanism of theasinensin A from tea

Theasinensin A is an important quality chemical component in tea, but its taste characteristics and the related mechanism are still unclear. The bitterness quantification and simulated taste mechanism of theasinensin A were researched. The results showed that theasinensin A was significantly correlated with the bitterness of tea. The bitterness threshold of theasinensin A was identified as 65 μmol/L for the first time. The dose-over-threshold (DOT) value of theasinensin A was significantly higher than that of caffeine in black tea soup. The concentration-bitterness curve and time-intensity curve of theasinensin A were constructed. The bitterness contribution of theasinensin A in black tea was higher than in oolong and green tea. Theasinensin A had the highest affinity with bitterness receptor protein TAS2R16, which was compared to TAS2R13 and TAS2R14. Theasinensin A was mainly bound to a half-open cavity at the N-terminal of TAS2R13, TAS2R14, and TAS2R16. The different binding capacity, hydrogen bond, and hydrophobic accumulation effect of theasinensin A and bitterness receptor proteins might be the reason why theasinensin A presented different bitterness senses in human oral cavity.

A natural whitening alternative from upcycled food waste (acid whey) and underutilized grains (millet)

The dairy industry faces a daunting challenge in managing acid whey (AW), a byproduct of Greek yogurt manufacturing that is costly to dispose of and challenging to incorporate into other food products. However, recent studies have demonstrated that AW can be transformed into a viable white powder by encapsulating it in millet flour. Recently, concerns over the safety of the commonly used food-grade whitener titanium dioxide (TiO₂) have arisen, and the search for an alternative food-whitening agent has become essential. This study evaluated the color attribute, proximate composition, sugar profile, amino acid profile, total phenolic content, antioxidant activity, and antinutrient content of the novel acid whey millet (AWM) powder. The L* values of the AWM powders were significantly higher than TiO₂ and the rest of the millet formulations. The crude protein content in the AWM powders was significantly (p < 0.05) lower when compared to the crude protein content in millet flours. AWM powders had higher lactose levels and retained all major amino acids after spray drying. Macrominerals (P, K, Ca, and Na) and microminerals (Zn and Cu) significantly increased in the AWM powder, while tannin content was reduced in AWM powders. These findings suggest that AWM powder is a white powder that contains a wide range of components with high nutritional value that could be readily incorporated into various applications. In summary, this study provides a valuable contribution to the dairy industry by highlighting the potential of AWM powders as a natural alternative food whitening agent to TiO₂.

Non-Volatile Compounds Involved in Bitterness and Astringency of Pulses: A Review

Despite the many advantages of pulses, they are characterised by off-flavours that limit their consumption. Off-notes, bitterness and astringency contribute to negative perceptions of pulses. Several hypotheses have assumed that non-volatile compounds, including saponins, phenolic compounds, and alkaloids, are responsible for pulse bitterness and astringency. This review aims to provide an overview highlighting the non-volatile compounds identified in pulses and their bitter and/or astringent characteristics to suggest their potential involvement in pulse off-flavours. Sensorial analyses are mainly used to describe the bitterness and astringency of molecules. However, in vitro cellular assays have shown the activation of bitter taste receptors by many phenolic compounds, suggesting their potential involvement in pulse bitterness. A better knowledge of the non-volatile compounds involved in the off-flavours should enable the creation of efficient strategies to limit their impact on overall perception and increase consumer acceptability.

Efficient removal of tannins from anaerobically-treated palm oil mill effluent using protein-tannin complexation in conjunction with electrocoagulation

Despite the significant removal of chemical oxygen demand (COD) by anaerobic digestion, anaerobically-treated palm oil mill effluent (POME) still contains tannins and other phenolic compounds, resulting in residual COD and a brownish color. In this study, we investigated the removal of tannins from anaerobically treated POME using protein-tannin complexation in conjunction with electrocoagulation. The amino acid composition of the protein, aqueous pH, and protein: tannin ratios were found to be important parameters affecting the tannin removal efficiency. Pig blood protein was superior to casein protein in removing tannins, possibly because it had aspartic acid as the major amino acid component. At an optimal condition with a pig blood protein: tannin ratio of 0.33 (w/w), a current density of 30 mA/cm², pH 5, and an electrolysis time of 10 min, the removals of tannins, COD, and color were 93%, 96%, and 97%, respectively.

Bitterness-masking assessment of luteolin encapsulated in whey protein isolate-coated liposomes

An unacceptable bitter taste limits the application of luteolin in healthier food systems. In this study, a bitterness-masking assessment was performed on whey protein isolate-coated liposomes loaded with luteolin (WPI-coated liposomes) using an electronic tongue and human sensory test. The physical properties of the WPI-coated colloidal nanocarrier were characterized by zeta potential, average diameter, distribution, and morphology analyses. The results indicated that WPI-coated nanocarrier systems exhibited a uniformly dispersed distribution and spherical morphology. After the comparison of the bitterness value, the bitterness-reducing effect of 5% WPI-coated liposomes was the most significant and reduced the bitterness of luteolin by 75%. Raman spectroscopy and X-ray diffraction analysis demonstrated that the decoration of WPI on the liposomes reduced the free motion of lipid molecules. This promoted the ordering at the polar headgroup area and hydrophobic core of the lipid bilayer, which explained why luteolin-loaded liposomes (uncoated liposomes) and WPI-coated liposomes could reduce the bitterness of luteolin from the perspective of bitter molecular groups. Combined with the Raman spectral data, the bilayer rigidity of 5% WPI-coated liposomes was positively responsive to the stabilization of uncoated liposomes against storage and resistance ability against surfactants. It was proven that the emergence of the surface modification of the WPI coating enhanced the stability of uncoated liposomes. These results may contribute to the use of WPI-coated liposomes as prospective candidates for effective delivery of the bioactive bitter substance in nutraceuticals and functional foods.

Processing of Sweet, Astringent and Pungent Oral Stimuli in the Human Brain

Taste and oral somatosensation are intimately related to each other from peripheral receptors to the central nervous system. Oral astringent sensation is thought to contain both gustatory and somatosensory components. In the present study, we compared the cerebral response to an astringent stimulus (tannin), with the response to one typical taste stimulus (sweet - sucrose) and one typical somatosensory stimulus (pungent - capsaicin) using functional magnetic resonance imaging (fMRI) of 24 healthy subjects. Three distributed brain sub-regions responded significantly different to the three types of oral stimulations: lobule IX of the cerebellar hemisphere, right dorsolateral superior frontal gyrus, and left middle temporal gyrus. This suggests that these regions play a major role in the discrimination of astringency, taste, and pungency.

Polyphenol-Dietary Fiber Conjugates from Fruits and Vegetables: Nature and Biological Fate in a Food and Nutrition Perspective

In the past few years, numerous studies have investigated the correlation between polyphenol intake and the prevention of several chronic diseases. Research regarding the global biological fate and bioactivity has been directed to extractable polyphenols that can be found in aqueous-organic extracts, obtained from plant-derived foods. Nevertheless, significant amounts of non-extractable polyphenols, closely associated with the plant cell wall matrix (namely with dietary fibers), are also delivered during digestion, although they are ignored in biological, nutritional, and epidemiological studies. These conjugates have gained the spotlight because they may exert their bioactivities for much longer than extractable polyphenols. Additionally, from a technological food perspective, polyphenols combined with dietary fibers have become increasingly interesting as they could be useful for the food industry to enhance technological functionalities. Non-extractable polyphenols include low molecular weight compounds such as phenolic acids and high molecular weight polymeric compounds such as proanthocyanidins and hydrolysable tannins. Studies concerning these conjugates are scarce, and usually refer to the compositional analysis of individual components rather than to the whole fraction. In this context, the knowledge and exploitation of non-extractable polyphenol-dietary fiber conjugates will be the focus of this review, aiming to access their potential nutritional and biological effect, together with their functional properties.

Bioactive Compounds, Antioxidant Activity and Sensory Properties of Northern Red Oak (Quercus rubra L., syn. Q. borealis F. Michx) Seeds Affected by Roasting Conditions

The nutritional value and health-promoting properties cause the fruits (acorns) of Quercus spp. to have great potential for use in the food industry as functional ingredients and antioxidants source. The aim of this study was to examine the bioactive compound's composition, antioxidant potential, physicochemical properties and taste characteristics of northern red oak (Quercus rubra L.) seeds subjected to roasting at different temperatures and times. The results indicate that the roasting markedly affects the composition of bioactive components of acorns. In general, the use of roasting temperatures greater than 135 °C causes a decrease in the total phenolic compound content of Q. rubra seeds. Furthermore, along with an increase in temperature and thermal processing time, a remarkable increase in melanoidins, which are the final products of the Maillard reaction, was also observed in processed Q. rubra seeds. Both unroasted and roasted acorn seeds had high DPPH radical scavenging capacity, ferric reducing antioxidant power (FRAP) and ferrous ion chelating activity. Roasting at 135 °C caused negligible changes in total phenolics content and antioxidant activity of Q. rubra seeds. Almost all samples had lower antioxidant capacity along with an increase in the roasting temperatures. Additionally, thermal processing of acorn seeds contributes to the development of the brown color and the reduction of bitterness, and the creation of a more pleasant taste of the final products. Overall, the results of this study show that both unroasted and roasted Q. rubra seeds may be an interesting source of bioactive compounds with high antioxidant activity. Therefore, they can be used as a functional ingredient of beverages or food.

Ultrasound-Assisted Extraction of Antioxidants from Melastoma malabathricum Linn.: Modeling and Optimization Using Box-Behnken Design

This study presents modeling and optimization of ultrasound-assisted extraction (UAE) of Melastoma malabathricum with the objective of evaluating its phytochemical properties. This one-factor-at-a-time (OFAT) procedure was conducted to screen for optimization variables whose domains included extraction temperature (X_ET), ultrasonic time (X_UT), solvent concentration (X_SC), and sample-to-liquid ratio (X_SLR). Response surface methodology (RSM) coupled with Box-Behnken design (BBD) was applied to establish optimum conditions for maximum antioxidant extraction. Modeling and optimization conditions of UAE at 37 kHz, X_ET 32 °C for X_UT 16 min and dissolved in an X_SC 70% ethanol concentration at a X_SLR 1:10 ratio yielded scavenging effects on 2,2-diphenyl-1-picryl-hydrazyl (DPPH) at 96% ± 1.48 and recorded values of total phenolic content (TPC) and total flavonoid content (TFC) at 803.456 ± 32.48 mg GAE (gallic acid equivalents)/g, and 102.972 ± 2.51 mg QE (quercetin equivalents)/g, respectively. The presence of high flavonoid compounds was verified using TWIMS-QTOFMS. Chromatic evaluation of phytochemicals using gas chromatography-mass spectrometry (GC-MS) revealed the presence of 14 phytocompounds widely documented to play significant roles in human health. This study provides a comparative evaluation with other studies and may be used for validation of the species' potential for its much-acclaimed medicinal and cosmeceutical uses.

An overview of bitter compounds in foodstuffs: Classifications, evaluation methods for sensory contribution, separation and identification techniques, and mechanism of bitter taste transduction

The bitter taste is generally considered an undesirable sensory attribute. However, bitter-tasting compounds can significantly affect the overall flavor of many foods and beverages and endow them with various beneficial effects on human health. To better understand the relationship between chemical structure and bitterness, this paper has summarized the bitter compounds in foodstuffs and classified them based on the basic skeletons. Only those bitter compounds that are confirmed by human sensory evaluation have been included in this paper. To develop food products that satisfy consumer preferences, correctly ranking the key bitter compounds in foodstuffs according to their contributions to the overall bitterness intensity is the precondition. Generally, three methods were applied to screen out the key bitter compounds in foods and beverages and evaluate their sensory contributions, including dose-over-threshold factors, taste dilution analysis, and spectrum descriptive analysis method. This paper has discussed in detail the mechanisms and applications of these three methods. Typical procedures for separating and identifying the main bitter compounds in foodstuffs have also been summarized. Additionally, the activation of human bitter taste receptors (TAS2Rs) and the mechanisms of bitter taste transduction are outlined. Ultimately, a conclusion has been drawn to highlight the current problems and propose potential directions for further research.

Biochemical analysis of anthocyanin and proanthocyanidin and their regulation in determining chickpea flower and seed coat colour

Flower and seed coat colour are important agronomic traits in chickpea (Cicer arietinum L.). Cultivated chickpeas are of two types namely, desi (dark seeded, purple flowered) and kabuli (light seeded, white flowered). There has been limited information about the molecular mechanism underlying colour variation of flower and seed coats in desi and kabuli chickpea. We profiled the anthocyanin and proanthocyanidin (PA) contents in chickpea flowers and seed coats. Tissue-specific silencing of two genes encoding a basic helix-loop-helix (CabHLH) protein and a tonoplast-localized multidrug and toxic compound extrusion (CaMATE1) transporter in a desi genotype resulted in the reduction in expression of anthocyanin and PA biosynthetic genes and anthocyanin and PA contents in the flower and seed coat, and produced flowers and seeds with kabuli characteristics. Transcriptional regulation of a subset of anthocyanin and PA biosynthetic genes by a natural CabHLH variant and transport assay of a natural CaMATE1 variant explained the association of these alleles with the kabuli phenotype. We carried out a detailed molecular characterization of these genes, and provided evidence that kabuli chickpea flower and seed colour phenotypes can be derived by manipulation of single genes in a desi chickpea background.

Reduction of phenolics in faba bean meal using recombinantly produced and purified Bacillus ligniniphilus catechol 2,3-dioxygenase

Pulse meal should be a valuable product in the animal feed industry based on its strong nutritional and protein profiles. However, it contains anti-nutritional compounds including phenolics (large and small molecular weight), which must be addressed to increase uptake by the industry. Microbial fermentation is currently used as a strategy to decrease larger molecular weight poly-phenolics, but results in the undesirable accumulation of small mono-phenolics. Here, we investigate cell-free biocatalytic reduction of phenolic content in faba bean (Vicia faba L.) meal. A representative phenolic ring-breaking catechol dioxygenase, Bacillus ligniniphilus L1 catechol 2,3-dioxygenase (BLC23O) was used in this proof-of concept based on its known stability and broad substrate specificity. Initially, large-scale fermentative recombinant production and purification of BLC23O was carried out, with functionality validated by in vitro kinetic analysis. When applied to faba bean meal, BLC23O yielded greatest reductions in phenolic content in a coarse air classified fraction (high carbohydrate), compared to either a fine fraction (high protein) or the original unfractionated meal. However, the upstream hydrolytic release of phenolics from higher molecular weight species (e.g. tannins, or complexes with proteins and carbohydrates) likely remains a rate limiting step, in the absence of other enzymes or microbial fermentation. Consistent with this, when applied to a selection of commercially available purified phenolic compounds, known to occur in faba bean, BLC23O was found to have high activity against monophenolic acids and little if any detectable activity against larger molecular weight compounds. Overall, this study highlights the potential viability of the biocatalytic processing of pulse meals, for optimization of their nutritional and economical value in the animal feed industry.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s40643-023-00633-8.

Evaluation of the safety and efficacy of wormwood vaginal gel in improving sexual function and sexual satisfaction in women of reproductive age: A randomized, triple-blinds, placebo-controlled clinical trial

INTRODUCTION

All aspects of sexual function are related to sexual satisfaction, and not paying attention to sexual problems leads to sexual dissatisfaction. According to studies, sexual satisfaction is a key factor in a couple's quality of life. The aim of this study was to evaluate the safety and efficacy of wormwood vaginal gel in improving sexual function and sexual satisfaction in women of reproductive age.

METHODS

This study was a randomized, triple-blinds, parallel-groups clinical trial performed on 76 women of reproductive age (18-45 years) referred to the gynecological clinic of Ghaem Hospital in Mashhad who had sexual dysfunction and low sexual satisfaction. 76 women were assigned to the wormwood gel (n = 38) and placebo (n = 38) groups using random permuted blocks of sizes 4 or 6 and an allocation ratio of 1:1. Wormwood gel or placebo was used for 4 weeks and 3 times a week for 4 weeks from22 May to 23 October 2021. The main data collection tools were the Female Sexual Function Index (FSFI) and Larson Sexual Satisfaction Questionnaire (LSSQ) to access changes in sexual function and sexual satisfaction at baseline and after 4 weeks.

RESULTS

The Mean and Standard Deviation of the age of the studied women was 36.8 ± 5.9 years in the intervention group and 37.1 ± 7.3 years in the placebo group. Before the intervention, the Mean and Standard Deviation of the total score of sexual function and sexual satisfaction in the studied women were 17.70 ± 3.66 and 72.20 ± 6.56 in the intervention group and in the placebo group were 18.23 ± 3.84 and 73.26 ± 5.86, respectively. At the end of the intervention, the Mean and Standard Deviation of the total score of female sexual function and sexual satisfaction in the intervention group were 32.11 ± 2.03 and 96.91 ± 7.93 and in the placebo group were 21.07 ± 3.22 and 75.91 ± 8.87, respectively. sexual function and satisfaction improved significantly in the wormwood gel compared to the control group(p < 0.0001).

CONCLUSIONS

Based on the findings of this trial, it seems that the wormwood vaginal gel can be used as a topical supplement to improve sexual function and sexual satisfaction in women of reproductive age who have sexual dysfunction and low sexual satisfaction.

Decoding the Proanthocyanins Profile of Italian Red Wines

The Italian wine appellations system is organized in hundreds of origin wines, with unique characteristics that are protected with many denominations of origin. The aim of this work was to analyze and compare the proanthocyanin profile of 12 single-cultivar and single-vintage Italian red wine groups (Aglianico from Campania, Cannonau from Sardinia, Corvina from Veneto, Montepulciano from Abruzzo, Nebbiolo from Piedmont, Nerello Mascalese from Sicily, Primitivo from Apulia, Raboso Piave from Veneto, Sagrantino from Umbria, Sangiovese from Tuscany and Romagna, and Teroldego from Trentino), each one produced in their terroirs under ad hoc legal frameworks to guarantee their quality and origin. All wines were analyzed with a protocol that combined the phloroglucinolysis reaction with an LC-MS/MS instrument. The results underlined Sagrantino wines as the richest in proanthocyanins. Sangiovese, Montepulciano, Nerello, and Teroldego were the richest in B-ring trihydroxylated flavan-3-ols, and especially Nerello was the richest in prodelphinidins. Cannonau, Raboso Piave, Nerello, and Corvina were characterized by C-ring trans conformation flavan-3-ols. Nebbiolo and Corvina had high percentages of galloylated flavan-3-ols. Aglianico and Primitivo had the lowest percentages of B-ring trihydroxylated and C-ring trans conformation flavan-3-ols. This information should be useful in better understanding the Italian red wines and valorize them.