Phytochemical exploration of Neolitsea pallens leaves using UPLC-Q-TOF-MS/MS approach.

Neolitsea pallens (D. Don) Momiyama & H. Hara (Family: Lauraceae), commonly known as Pale Litsea, is an evergreen small tree, distributed in India at altitudes of 1500-3000 m. Traditionally utilized for various purposes, its leaves and bark are used as spices, and the plant is valued in preparing a hair tonic from freshly pressed juice. Secondary metabolites of the leaves have not comprehensively been analysed so far. The objective of the study was to determine the chemical composition of the leaves by analysing their 25% aqueous methanol extract with the aid of ultra-performance liquid chromatography quadrupole time of flight tandem mass spectrometry. Overall, 56 compounds were identified in the study. Phenolics represented by phenolic acids, phenolic glycosides, proanthocyanidins, and flavonoids were the main components of the extract.

Optimization of sensory properties of ultrasound-treated strawberry vinegar.

Vinegar is renowned for its benefits to human health due to the presence of antioxidants and bioactive components. Firstly, this study optimized the production conditions of ultrasound-treated strawberry vinegar (UT-SV), known for its high consumer appeal. The sensory properties of UT-SV were optimized by response surface methodology (RSM) to create the most appreciated strawberry vinegar. Secondly, various quality parameters of conventional strawberry vinegar (C-SV), UT-SV, and thermally pasteurized strawberry vinegar (P-SV) samples were compared. RSM was employed to craft the best strawberry vinegar based on consumers ratings of UT-SV. Sensory characteristics, bioactive values, phenolic contents, and organic acid contents of C-SV, UT-SV, and P-SV samples were assessed. Through optimization, the ultrasound parameters of the independent variables were determined as 5.3 min and 65.5 % amplitude. The RSM modeling levels exhibited high agreement with pungent sensation at 98.06 %, aromatic intensity at 98.98 %, gustatory impression at 99.17 %, and general appreciation at 99.26 %, respectively. Bioactive components in UT-SV samples increased after ultrasound treatment compared to C-SV and P-SV samples. Additionally, the amount of malic acid, lactic acid, and oxalic acid increased after ultrasound treatment compared to C-SV samples. Ultimately, UT-SV with high organoleptic properties was achieved. The ultrasound treatment positively impacted the bioactive values, phenolic and organic acid content, leading to the development of a new and healthy product.

Effect of ultrasonic treatment during fermentation on the quality of fortified sweet wine.

The present study aimed to investigate the potential of ultrasonic treatment during fermentation for enhancing the quality of fortified wines with varying time and power settings. Chemical analysis and sensory evaluation were conducted to assess the impact of ultrasonic treatment on wine quality. Results showed that ultrasonic treatment could increase total anthocyanin and total phenol content, reduce anthocyanin degradation rate, and improve color stability. Moreover, ethyl carbamate content was lower in the ultrasonic group after aging compared to non-ultrasonic group. A combination of 200 W for 20 min resulted in higher sensory scores and more coordinated taste, while a combination of 400 W for 40 min produced higher levels of volatile compounds (21860.12 µg/L) leading to a richer and more elegant aroma. Therefore, ultrasound can be used as a potential technology to improve the quality of wine.

Effect of Laurus nobilis on bacteria and human transforming growth factor-ß1.

OBJECTIVE: In this study, we aimed to determine the phenolic compounds, the antibacterial activity of extract from Laurus nobilis leaves, and its possible effect on transforming growth factor-ß1 expression level in peripheral blood mononuclear cells. METHODS: The phenolic components of Laurus nobilis were identified by the high-performance liquid chromatography method. The antibacterial activity of this extract was determined by disk diffusion and broth microdilution methods. The transforming growth factor-ß1 expression was analyzed using the RT-qPCR method. RESULTS: Epicatechin was found in the highest amount and o-coumaric acid in the lowest amount. The half-maximal inhibitory concentration (IC50) was determined to be 55.17 µg/mL. The zones of inhibition and minimum inhibitory concentration for Staphylococcus aureus, Enterococcus faecalis, and Klebsiella pneumoniae were 15, 14, and 8 mm and 125, 250, and 1000 µg/mL, respectively. The change in transforming growth factor-ß1 expression levels was found to be statistically significant compared with the control groups (p<0.0001). CONCLUSION: Laurus nobilis extract was found to be effective against bacteria and altered the expression level of transforming growth factor-ß1 in peripheral blood mononuclear cells.

Unraveling the effect of phenolic extract derived from olive mill solid wastes on agro-physiological and biochemical traits of pomegranate and its associated rhizospheric soil properties.

Agricultural waste management poses a significant challenge in circular economy strategies. Olive mill wastes (OMW) contain valuable biomolecules, especially phenolic compounds, with significant agricultural potential. Our study evaluate the effects of phenolic extract (PE) derived from olive mill solid wastes (OMSW) on pomegranate agro-physiological and biochemical responses, as well as soil-related attributes. Pomegranate plants were treated with PE at doses of 100 ppm and 200 ppm via foliar spray (L100 and L200) and soil application (S100 and S200). Results showed increased biomass with PE treatments, especially with soil application (S100 and S200). Proline and soluble sugar accumulation in leaves suggested plant adaptation to PE with low-level stress. Additionally, PE application reduced malondialdehyde (MDA) and hydrogen peroxide (H2O2) contents. Higher doses of PE (S200) significantly improved net photosynthesis (Pn), transpiration rate (E), water use efficiency (WUEi), and photosynthetic efficiency (fv/fm and PIabs). Furthermore, PE treatments enhanced levels of chlorophylls, carotenoids, polyphenols, flavonoids, and antioxidant activity. Soil application of PE also increased soil enzyme activities and microbial population. Our findings suggest the beneficial impact of PE application on pomegranate agro-physiological responses, laying the groundwork for further research across various plant species and soil types to introduce nutrient-enriched PE as an eco-friendly biostimulant.

Differences in physicochemical properties of pectin extracted from pomelo peel with different extraction techniques.

In order to obtain high yield pomelo peel pectin with better physicochemical properties, four pectin extraction methods, including hot acid extraction (HAE), microwave-assisted extraction (MAE), ultrasound-assisted extraction, and enzymatic assisted extraction (EAE) were compared. MAE led to the highest pectin yield (20.43%), and the lowest pectin recovery was found for EAE (11.94%). The physicochemical properties of pomelo peel pectin obtained by different methods were also significantly different. Pectin samples obtained by MAE had the highest methoxyl content (8.35%), galacturonic acid content (71.36%), and showed a higher apparent viscosity, thermal and emulsion stability. The pectin extracted by EAE showed the highest total phenolic content (12.86%) and lowest particle size (843.69 nm), showing higher DPPH and ABTS scavenging activities than other extract methods. The pectin extracted by HAE had the highest particle size (966.12 nm) and degree of esterification (55.67%). However, Fourier-transform infrared spectroscopy showed that no significant difference occurred among the different methods in the chemical structure of the extracted pectin. This study provides a theoretical basis for the industrial production of pomelo peel pectin.

Rapid characterization of non-volatile phenolic compounds reveals the reliable chemical markers for authentication of traditional Chinese medicine Xiang-ru among confusing Elsholtzia species.

The aerial parts of Mosla chinensis Maxim. and Mosla chinensis cv. 'Jiangxiangru' (MCJ) are widely utilized in traditional Chinese medicine (TCM), known collectively as Xiang-ru. However, due to clinical effectiveness concerns and frequent misidentification, the original plants have increasingly been substituted by various species within the genera Elsholtzia and Mosla. The challenge in distinguishing between these genera arises from their similar morphological and metabolic profiles. To address this issue, our study introduced a rapid method for metabolic characterization, employing high-resolution mass spectrometry-based metabolomics. Through detailed biosynthetic and chemometric analyses, we pinpointed five phenolic compounds-salviaflaside, cynaroside, scutellarein-7-O-D-glucoside, rutin, and vicenin-2-among 203 identified compounds, as reliable chemical markers for distinguishing Xiang-ru from closely related Elsholtzia species. This methodology holds promise for broad application in the analysis of plant aerial parts, especially in verifying the authenticity of aromatic traditional medicinal plants. Our findings underscore the importance of non-volatile compounds as dependable chemical markers in the authentication process of aromatic traditional medicinal plants.

Sequential extraction of anthocyanins and pectin from jabuticaba (Plinia cauliflora) peel: Peel pretreatment effect and ultrasound-assisted extraction.

The jabuticaba bark is rich in anthocyanins and fibers, and its use may be of industrial interest. In the food sector, its used as an ingredient in the production of fermented products, liqueurs or enriched flours. It also has pharmaceutical and cosmetic applications. The objective was to evaluate the effect of pretreatment and fresh use of jabuticaba peels in the extraction of total phenolic compound (TPC) and total anthocyanin (TA) contents with and without ultrasound assistance and in the sequential extraction of pectin from the residue. In the TPC and TA extraction, a 3x2 factorial design was used. For conventional anthocyanin extraction (CAE), occurred in an incubator under agitation. For ultrasound-assisted anthocyanin extraction (UAE) was utilized an ultrasonic homogenizer with probe (20 kHz, 160 W). The extracts were quantified (TPC, TA, antioxidant activity and color). The residues were characterized and used for sequential pectin extraction, which was quantified and characterized. The results were subjected to analysis of variance. Fresh jabuticaba peel is a residue that can be used to sequentially extract phenolic compounds, particularly anthocyanins and pectin. The use of ultrasound (UAE) was less efficient than CAE for extracting TPC and TA or performing sequential extraction on all pretreatment peels.

Crataegus pentagyna willd. Fruits, leaves and roots: phytochemicals, antioxidant and antimicrobial potentials.

BACKGROUND: The hawthorn has recently been used as a popular herbal medicine in food applications and phytotherapy, especially for the cardiovascular system. METHODS: In this study, phytochemicals were evaluated by LC-ESI-MS, GC-MS, and biological activity, including antioxidant (DPPH test) and antibacterial (broth dilution assay), in different extracts of Crataegus pentagyna fruit, leaf, and root. RESULTS: Globally, 49 phenolics were tentatively identified using HPLC-ESI-MS/MS in the hydro-methanolic extract of the fruit (major apigenin, caffeoylquinic acid derivative, and 4-O-(3'-O-glucopyranosyl)-caffeoyl quinic acid), 42 in the leaf (major salicylic acid, naringenin-6-C-glucoside, and naringin), and 33 in the root (major naringenin-7-O-neohesperidoside, isovitexin-2″-O-rhamnoside, and 4-O-(3'-O-glucopyranosyl)-caffeoyl quinic acid). The major group compounds analyzed by GC-MS in petroleum ether extracts were hydrocarbons (63.80%) and fatty acids and their derivatives (11.77%) in fruit, hydrocarbons (49.20%) and fatty acids and their derivatives (13.85%) in leaf, and hydrocarbons (53.96%) and terpenes (13.06%) in root. All samples exhibited promising phytochemical profile (total phenol, flavonoid, phenolic acid, and anthocyanin), antioxidant and antibacterial capacities, especially in hydro-methanolic extract of fruit (210.22 ± 0.44 mg GAE/g DE; 79.93 ± 0.54 mg QE/g DE; 194.64 ± 0.32 mg CAE/g DE; 85.37 ± 0.13 mg cyanidin 3-glucoside/100 g FW; DPPH: 15.43 ± 0.65 µg/mL; MIC: 0.15-0.62 µg/mL; and MBC: 0.62-1.25 mg/mL), followed by the leaf and root extracts, respectively. The PCA and heatmap analysis results distinguished metabolite profile differences for samples. CONCLUSION: The results of the present work provide scientific support for C. pentagyna as antimicrobial agents and natural antioxidants in human health and food preservation.

Essential oil composition, morphological characterization, phenolic content and antioxidant activity of Iranian populations of Hymenocrater longiflorus Benth. (Lamiaceae).

The study focused on the morphological and chemical characteristics of 200 Hymenocrater longiflorus Benth. genotypes found in natural habitats of eight regions in west of Iran. The primary objective of the study was to assess the morphological and phytochemical variability within populations grown in their natural habitats, with the aim of identifying their potential for domestication and utilization in pre-breeding programs. The plant height (PH) ranged from 50.32 to 69.65 cm, with the highest observed in population P8. The internode distances ranged from 4.7 to 6.47 cm, with the maximum distance found in P4. Flower lengths varied from 1.95 to 2.45 cm, with the minimum and maximum values observed in P4 and P3, respectively. The highest leaf length (5.20 cm) and width (3.87 cm) were recorded in P2. The aerial parts of the plant were utilized to extraction and determine the essential oil (EO) content and composition, which ranged from 0.40 to 0.78% (v/w). The analysis of EO by gas chromatography (GC) and gas chromatography mass spectrometry (GC/MS) identified 26 compounds, constituting 99-99.5% of the EOs. The main compounds in the EO and their percentage range (v/w DW) were tau-cadinol (0.62-55.56), mono (2-ethylhexyl) phthalate (8.10-94.70), elemol (0.21-19.11), ß-spathulenol (0.08-14.39), 4-terpineol (0.23-10.19), and ß-eudesmol (0.21-9.94). The main chemical groups found in EOs included oxygenated sesquiterpenes (1.12-68.43), and phthalates (9.73-94.72). Cluster analysis revealed three distinct chemotypes: chemotype I (populations 1 and 2) with major components of mono (2-ethylhexyl) phthalate, tau-cadinol, and α-elemol; chemotype II (population 5) rich in mono (2-ethylhexyl) phthalate; and chemotype III (populations 3, 4, 6-8) containing tau-cadinol, ß-eudesmol, and 4-terpineol. The study also evaluated total phenolic, total flavonoid, and DPPH free radical scavenging activity in the fifty percent inhibitory concentration (IC50) in leaf and flower samples of the genotypes, along with estimating total anthocyanin content in the flower samples. The total phenolic content (TPC) in leaf and flower samples ranged from 7.89 to 107.18 mg GAE/g DW and 39.98 to 86.62 mg gallic acid equivalent (GAE)/g DW, respectively. Total flavonoid content (TFC) ranged from 81.04 to 143.46 mg QUE/g DW in leaf samples and from 94.82 to 133.26 mg quercetin equivalent (QUE)/g DW in flower samples. DPPHsc IC50 (µg/mL) ranged from 0.65 to 78.74 in leaf samples and from 4.38 to 7.71 in flower samples. Anthocyanin content ranged from 1.89 to 3.75 mg cyanidin-3-glucoside equivalent (C3GE)/g DW among populations. Canonical correspondence analysis and simple correlation demonstrated a strong association and correlations among the studied attributes. The negative correlations between leaf DPPH (DPPH L) IC50 and TFC (- 0.73), TPC (- 0.63), Elemol (- 0.90), and EO (- 0.85) indicate that these compounds have a significant impact on the antioxidant activity of the leaves. Furthermore, Fruit DPPH (DPPH F) IC50 showed a negative correlation with TPC (- 0.79) and TFC (- 0.78), but a positive correlation with flower anthocyanins (0.51), (Z)-ß-Farnesene (0.66), and 4-Terpineol (0.57). Circular cluster analysis categorized the genotypes of all individuals in the eight studied populations into three main categories based on all the studied traits, indicating significant variation in phytochemical and morphological traits among populations, surpassing the within-populations variation.

Chemical Constituents of Stinging Nettle (Urtica dioica L.): A Comprehensive Review on Phenolic and Polyphenolic Compounds and Their Bioactivity.

Polyphenolic compounds are of great interest in today's science. Naturally, they occur in plants and other sources in many different forms. Their wide range of biological activity has attracted the attention of the scientific community. One of the sources of phenolic compounds is stinging nettle (Urtica dioica L.), a common plant in almost all parts of the world. A long tradition of utilization and an interesting chemical profile make this plant a fascinating and extensive object of study. The chemical profile also allows this plant to be used as a food and a pigment source in the food, pharmaceutical, and cosmetic industries. Previously conducted studies found phenolic acids and polyphenolic compounds in root, stalk, and stinging nettle leaves. Different extraction techniques were usually used to isolate them from the leaves. Obtained extracts were used to investigate biological activity further or formulate different functional food products. This study aimed to collect all available knowledge about this plant, its chemical composition, and biological activity and to summarize this knowledge with particular attention to polyphenolic compounds and the activity and mechanisms of their actions.

Metabolomic Comparison of Guava (Psidium guajava L.) Leaf Extracts Fermented by Limosilactobacillus fermentum and Lactiplantibacillus plantarum and Their Antioxidant and Antiglycation Activities.

Probiotic fermentation of plant-based materials can lead to the generation of various bioactive substances via bacterial metabolites and the biotransformation of phenolic compounds. We compared the metabolic differences between fermentation by Limosilactobacillus fermentum KCTC15072BP (LFG) and fermentation by Lactiplantibacillus plantarum KGMB00831 (LPG) in guava leaf extract (0%, 0.5%, and 2% (w/v))-supplemented medium via non-targeted metabolite profiling. By performing multivariate statistical analysis and comparing the different guava leaf extract groups, 21 guava-derived and 30 bacterial metabolites were identified. The contents of guava-derived glucogallin, gallic acid, and sugar alcohols were significantly higher in LFG than they were in LPG. Similarly, significantly higher contents of guava-derived pyrogallol, vanillic acid, naringenin, phloretin, and aromatic amino acid catabolites were obtained with LPG than with LFG. LFG led to significantly higher antioxidant activities than LPG, while LPG led to significantly higher antiglycation activity than LFG. Interestingly, the fermentation-induced increase in the guava-leaf-extract-supplemented group was significantly higher than that in the control group. Thus, the increased bioactivity induced by guava fermentation with the Lactobacillaceae strain may be influenced by the synergistic effects between microbial metabolites and plant-derived compounds. Overall, examining the metabolic changes in plant-based food fermentation by differentiating the origin of metabolites provides a better understanding of food fermentation.

Characterization of alkaloids and phenolics in Nitraria roborowskii Kom. fruit by UHPLC-triple-TOF-MS/MS and its sucrase and maltase inhibitory effects.

Nitraria roborowskii Kom (NRK), with high economic and ecological value, is mainly distributed in the Qaidam Basin, China. However, research on its chemical components and bioactivities is still rare. In this study, its chemical constituents (52) including 10 ß-carboline alkaloids, nine cyclic peptides, three indole alkaloids, five pyrrole alkaloids, eight phenolic acids and 17 flavonoids were identified tentatively using UPLC-triple-TOF-MS/MS. Notablely, one new ß-carboline alkaloid and five new cyclic peptides were confirmed using MS/MS fragmentation pathways. In addition, experiments in vitro indicated that NRK-C had strong maltase and sucrase inhibitory activities (IC50 of 0.202 and 0.103 mg/mL, respectively). Polysaccharide tolerance experiments confirmed NRK-C (400 mg/kg) was associated with decreased postprandial blood glucose (PBG) in diabetic mice. These results suggested that NRK fruit might be used as a functional ingredient in food products.

Polyphenolic profile and in vitro biological activity of Serbian orange (skin fermented white) wines.

Orange wines are made from white grapes, but with prolonged skin contact during fermentation. Available data on their composition and potential health benefits are limited, so polyphenolic profile (HPLC analysis) and in vitro biological activities (enzyme inhibition, antioxidant, and anti-inflammatory) of 24 Serbian orange wines were analyzed, including the correlation between determined composition and bioactivities. The wines displayed distinct polyphenolic profiles, enabling partial differentiation based on overall polyphenol content, including dominant components (catechin, gallic and caffeic acids), along with occasional occurrences of anthocyanins. However, no discernible distinctions were noted based on grape varieties, vintage, or producer. All twenty-four orange wines showed a reasonable inhibition of digestive enzymes and lipid peroxidation, twenty-one samples reduced ROS generation in the cell-based assay, but only two suppressed both PGE2 and TXA2 production in U937 cells, implicating possible functional food properties. No significant correlation between polyphenolic profile and determined biological activities was noticed.

Effects of post-fermentation addition of green tea extract for sulfur dioxide replacement on Sauvignon Blanc wine phenolic composition, antioxidant capacity, colour, and mouthfeel attributes.

This study examines the feasibility of replacing SO2 in a New Zealand Sauvignon Blanc wine with a green tea extract. The treatments included the control with no preservatives (C), the addition of green tea extract at 0.1 and 0.2 g/L (T1 and T2), and an SO2 treatment at 50 mg/L (T3). Five monomeric phenolic compounds were detected in the green tea extract used for the experiment, and their concentrations ranged in the order (-)-epigallocatechin gallate > (-)-epigallocatechin > (-)-epicatechin > (-)-epicatechin gallate > gallic acid. At the studied addition rates, these green tea-derived phenolic compounds contributed to ∼70% of the antioxidant capacity (ABTS), ∼71% of the total phenolic index (TPI), and âˆ¼ 84% of tannin concentration (MCPT) of the extract dissolved in a model wine solution. Among wine treatments, T1 and T2 significantly increased the wine's colour absorbance at 420 nm, MCPT, gallic acid and total monomeric phenolic content. TPI and ABTS were significantly higher in wines with preservatives (i.e., T2 > T1 â‰… T3 > C, p < 0.05). These variations were observed both two weeks after the treatments and again after five months of wine aging. Additionally, an accelerated browning test and a quantitative sensory analysis of wine colour and mouthfeel attributes were performed after 5 months of wine aging. When exposed to excessive oxygen and high temperature (50 °C), T1 and T2 exhibited ∼29% and 24% higher browning capacity than the control, whereas T3 reduced the wine's browning capacity by ∼20%. Nonetheless, the results from sensory analysis did not show significant variations between the treatments. Thus, using green tea extract to replace SO2 at wine bottling appears to be a viable option, without inducing a negative impact on the perceptible colour and mouthfeel attributes of Sauvignon Blanc wine.

Breads formulated with avocado pulp powder as a fat substitute: Quality parameters and in vitro inhibition activities.

The aim of the current study was to evaluate the influence of increasing contents (5%-25%) of avocado pulp powder (APP) produced by foam-mat drying (FMD) as a substitute for hydrogenated vegetable fat in bread on its nutritional composition, physical properties, α-amylase, α-glucosidase, and lipase inhibition, total phenolic content, antioxidant activity, color, structure, and x-ray diffraction patterns. The increase in the APP content decreased the values of lipids, carbohydrates, energy, firmness, and specific volume of breads. The inhibition of lipase activity showed a pronounced increase, while the total phenolic content and antioxidant activity were significantly elevated. The color parameters a* and b* were higher in the breads with added APP. The crystalline structure transitioned from type A to type V with 15% APP incorporation. Taken together, these results suggest that APP has potential to act as a healthier substitute for saturated fats in breads, paving the way to develop creative and innovative solutions for the functionalization of bakery food products.

Eco-friendly extraction of antibacterial compounds from enriched olive pomace: a design-of-experiments approach to sustainability.

The increasing interest in utilizing olive pomace bioactive molecules to advance functional elements and produce antioxidant and antimicrobial additives underscores the need for eco-friendly extraction and purification methods. This study aims to develop an eco-friendly extraction method to evaluate the effect of extraction parameters on the recovery of bioactive molecules from enriched olive pomace. The effects were identified based on total phenolic and flavonoid contents and antioxidant activity, employing a design of experimental methodology. The positive and the negative simultaneous effects showed that among the tested enrichments, those incorporating Nigella Sativa, dates, and coffee demonstrated superior results in terms of the measured responses. Furthermore, chromatographic analysis unveiled the existence of intriguing compounds such as hydroxytyrosol, tyrosol, and squalene in distinct proportions. Beyond this, our study delved into the structural composition of the enriched pomace through FTIR analysis, providing valuable insights into the functional groups and chemical bonds present. Concurrently, antimicrobial assays demonstrated the potent inhibitory effects of these enriched extracts against various microorganisms, underscoring their potential applications in food preservation and safety. These findings highlight enriched olive pomace as a valuable reservoir of bioactive molecules for food products since they can enhance their anti-oxidative activity and contribute to a sustainable circular economy model for olive oil industries.

Blackcurrant press cake by-product: Increased chemical bioaccessibility and reduced antioxidant protection after in vitro simulation of gastrointestinal digestion.

This study describes the bioaccessibility in terms of total phenolic content (TPC) and antioxidant capacity before and after in vitro digestion from blackcurrant press cake extracts (BPC) and the bioactivity in cell culture, human erythrocytes as well as the in silico analysis. Chemical analysis of BPC presented an increase in TPC (270%) and anthocyanins (136%) after in vitro digestion, resulting in an improvement of antioxidant activity (DPPH 112%; FRAP: 153%). This behavior may be related to the highest activity of cyanidin-3-rutinoside, as confirmed by in silico analysis. The digested BPC did not exert cytotoxicity in cells and showed less antioxidant activity against the oxidative damage induced in endothelial cells and human erythrocytes compared to the non-digested extract. The results raise a question about the reliability we should place on results obtained only from crude samples, especially those that will be used to produce foods or nutraceuticals.

Protein extracts from amaranth and quinoa as novel fining agents for red wines.

Due to allergenic concerns, only pea, potato, and wheat proteins have been approved as alternatives for replacing animal-based fining agents in wines. In pursuit of other substitutes, this work aimed to determine the fining ability of amaranth (Amaranthus caudatus L.) proteins (AP) in red wine, compared to quinoa (Chenopodium quinoa Willd.) (QP) and a commercial pea protein. Phenolic and volatile composition, as well as color characteristics, were analyzed. AP was as effective as QP at decreasing condensed tannins, with AP at 50 g/hL being the most effective treatment (25.6% reduction). QP and AP produced a minor or no statistical change in the total anthocyanins and wine color intensity. They reduced the total ester concentration, but the total alcohols remained unchanged. The outcomes of AP and QP were similar, and sometimes better than the pea proteins, thus suggesting that they could be promising options for the development of novel fining agents.

Potential retention of dissolved organic matter by soil minerals during wetland water-table fluctuations.

Wetlands export large amounts of dissolved organic carbon (DOC) downstream, which is sensitive to water-table fluctuations (WTFs). While numerous studies have shown that WTFs may decrease wetland DOC via enhancing DOC biodegradation, an alternative pathway, i.e., retention of dissolved organic matter (DOM) by soil minerals, remains under-investigated. Here, we conducted a water-table manipulation experiment on intact soil columns collected from three wetlands with varying contents of reactive metals and clay to examine the potential retention of DOM by soil minerals during WTFs. Using batch sorption experiments and Fourier transform ion cyclotron resonance mass spectrometry, we showed that mineral (bentonite) sorption mainly retained lignin-, aromatic- and humic-like compounds (i.e., adsorbable compounds), in contrast to the preferential removal of protein- and carbohydrate-like compounds during biodegradation. Seven cycles of WTFs significantly decreased the intensity of adsorbable compounds in DOM (by 50 ± 21% based on fluorescence spectroscopy) and DOC adsorbability (by 2-20% and 1.9-12.7 mg L-1 based on batch sorption experiment), to a comparable extent compared with biodegradable compounds (by 11-32% and 1.6-15.2 mg L-1). Furthermore, oxidation of soil ferrous iron [Fe(II)] exerted a major control on the magnitude of potential DOM retention by minerals, while WTFs increased mineral-bound lignin phenols in the Zoige soil with the highest content of lignin phenols and Fe(II). Collectively, these results suggest that DOM retention by minerals likely played an important role in DOC decrease during WTFs, especially in soils with high contents of oxidizable Fe. Our findings support the 'iron gate' mechanism of soil carbon protection by newly-formed Fe (hydr)oxides during water-table decline, and highlight an underappreciated process (mineral-DOM interaction) leading to contrasting fate (i.e., preservation) of DOC in wetlands compared to biodegradation. Mineral retention of wetland DOC hence deserves more attention under changing climate and human activities.