Since ancient times, numerous philosophers and scientists have not only wondered about the physical nature of light but also of how it interacts with the human eye to induce the neuronal signals to the brain that ultimately create the sensation of "color" in our minds. An enormous body of literature has accumulated and this chapter aims at compiling relevant and, sometimes, simply interesting aspects about the biological and physical fundamentals needed for a profound understanding of the colors of foods and beverages. The chapter begins with a brief historical, narrative review about how our understanding of color has evolved throughout the centuries. Then, the biological fundamentals will be introduced, including a section on the anatomy of the eye with its most sophisticated multicellular neuronal photoreceptor systems. Then physical fundamentals of the multitude of ways of how colors can be created will be explained with a focus on, but not exclusively on, colors in foods and beverages. The chapter was designed to help scientists, developers, and any interested readers to introduce themselves to the physical and biological backgrounds relevant for the field of food and beverage coloration.
Grapevine downy mildew caused by Plasmopara viticola is a deleterious vine disease currently controlled using synthetic and copper-based fungicides. Environmental concerns surrounding such fungicides necessitate sustainable alternatives like grape cane extracts. However, studies into their efficacy and effects on the product remain limited. This study aimed to assess the open-field efficacy of a novel grape cane extract formulation, alone and combined with a copper agent, against downy mildew, and to examine its impact on berry and must composition. The results were compared to standard fungicides frequently used in integrated and organic viticulture. In 2022, the grape cane extract formulation reduced downy mildew severity by 78 % on berry clusters, comparable to the maximum acceptable dose of copper for organic farming in Germany (3 kg/ha/a). Combining the grape cane extract with the copper agent was more effective than the copper agent alone, but not more effective than the grape cane extract alone. In 2023, disease development was marginal, despite artificial inoculation. Compositional differences detectable by FTIR were insignificant between musts derived from all treatments, increased copper levels were observed whenever copper had been applied. The phenolic content in freeze-dried, de-seeded berries of 2022 was significantly lower after copper (14.6 mg/g dry weight DW) and grape cane extract treatments (6.6 mg/g DW) when compared to the control (36.1 mg/g DW), with discrepancies in stilbenoid and flavan-3-ol levels in particular, as analysed by HPLC-DAD. However, these differences were not confirmed in 2023, with results showing no correlations between different treatments and phenolic contents. These findings suggest that applications of the phenolic grape cane extract do not lead to artificially altered levels or relevant residues of the active constituents; i.e., the phenolic compounds in the product. In brief, grape cane extracts might represent a promising natural alternative to controlling grapevine downy mildew, particularly in organic viticulture, which, to date, heavily relies on (eco-)toxic copper-pesticides. Further multi-year studies including wine analyses are warranted to follow the entire flow towards the final product.
Protein removal with aspergillopepsin in combination with short-time heating has recently emerged as an opportunity for winemakers to prevent protein haze in wine. In this study, we first treated a protein-rich must and wine with two different aspergillopepsin preparations along an identical control treatment without enzyme addition on a pilot plant scale. While treating wines was rather ineffective, treating musts was effective in reducing protein concentrations by up to 86%, leading to haze-stable wines according to the common heat test. Varying thermal loads in further experiments, a rather mild heat treatment of 65 degrees C for 30 s compared to those in earlier studies was found sufficient for enzymatic protein degradation. Treating must from a fungus-resistant variety (cv. Fidelio) was as successful as treating must from a blend of conventional varieties (cv. Gewurztraminer/Muller-Thurgau). Triangle sensory tests found no clear evidence of an effect on the quality by heat treatments with and without enzyme dosage.
Potentially health-promoting concentrations of flavan-3-ols were previously shown to be retained in apple juices produced with the emerging spiral filter press. Due to the novelty of this technology, the factors governing the stability of flavan-3-ol-rich apple juices have only scarcely been studied. Therefore, we produced flavan-3-ol-rich apple juices and concentrates (16, 40, 70 degrees Brix) supplemented with ascorbic acid (0.0, 0.2, 1.0 g/L) according to common practice. Flavan-3-ols (DP1-7) and twelve flavan-3-ol reaction products were comprehensively characterized and monitored during storage for 16 weeks at 20 and 37 degrees C, employing RP-UHPLC- and HILIC-DAD-ESI (-)-QTOF-HR-MS/MS. Flavan-3-ol degradation followed a second-order reaction kinetic, being up to 3.5-times faster in concentrates (70 degrees Brix) than in single strength juices (16 degrees Brix). Furthermore, they diminished substantially faster compared to other phenolic compounds. For instance, after 16-weeks at 20 degrees C, the maximum loss of flavan-3-ols (-70 %) was greater than those of hydroxycinnamic acids (-18 %) and dihydrochalcones (-12 %). We observed that flavan-3-ols formed adducts with sugars and other carbonyls, such as 5-(hydroxymethyl) furfural and the ascorbic acid-derived L-xylosone. Increased degradation rates correlated particularly with increased furan aldehyde levels as found in concentrates stored at elevated temperatures. These insights could be used for optimizing production, distribution, and storage of flavan-3-ol-rich apple juices and other foods and beverages.
The retention of flavan-3-ols and other phenolic compounds during apple juice production at pilot plant scale (200 kg, cv. Boskoop) was investigated. An oxygen-excluding spiral filter press and a conventional decanter were used with and without pectinase mash treatment. Phenolic compounds were comprehensively identified and quantitated by RP-UHPLC and HILIC, both coupled to DAD-FLD and DAD-ESI(-)-QTOF-HR-MS/MS. These techniques combined with using a NIST cocoa flavan-3-ol standard allowed for the first time an individual quantification of flavan-3-ol fractions (DP 1-7) in apple juices. Spiral filter-pressed juices were exposed to less oxidation and exhibited four times higher total phenolic compound levels than decanter-made juices (1016 vs. 262 mg/L). Apple juices derived from pectinase-treated mashes had lower total phenolic compound levels than their non-treated counterparts. However, those made by spiral filter press still retained significantly higher concentrations (780 vs. 104 mg/L). Flavan-3-ols were especially well retained by spiral filter press processing, reaching unprecedentedly high concentrations of up to 713 mg/L. A 280 mL serving of non-treated spiral filter-pressed juice would therefore suffice to provide the daily intake of 200 mg flavan-3-ols, equaling the dose of cocoa flavan-3-ols associated with an authorized European health claim for healthy blood flow.
SCOPE:Excessive activation of the nucleotide-binding oligomerization domain-like receptor pyrin domain-containing protein 3 (NLRP3) inflammasome contributes to chronic inflammation. Thus, targeting NLRP3 inflammasome activation by anthocyanins may prevent inflammatory diseases. Therefore, the present study determines the influence of a black carrot extract (BCE) with high amounts of acylated anthocyanins and their related phenolic acids on the NLRP3 inflammasome. METHODS AND RESULTS:THP-1 monocytes are pretreated with a BCE, cyanidin-3-glucoside (C3G), or hydroxycinnamic acids. NLRP3 inflammasome assembly is initiated by priming THP-1 monocytes with lipopolysaccharide and/or activating the NLRP3 inflammasome with nigericin. Flow cytometry is used to assess apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) speck formation, as well as ASC and NLRP3 protein expression. Caspase-1 activity is measured using a bioluminescent assay, and cytokine concentrations are determined by enzyme-linked immunosorbent assays (ELISA). C3G and phenolic acids diminish ASC and NLRP3 protein expression. In addition, C3G and phenolic acids attenuate ASC speck formation. Furthermore, the BCE and C3G decline caspase-1 activity. Consistently, IL-1β and IL-18 secretion are reduced upon NLRP3 inflammasome activation. CONCLUSION:The present study shows that a BCE with high amounts of acylated anthocyanins and their related phenolic acids diminish priming and activation of the NLRP3 inflammasome in THP-1 monocytes.
The present experiment addressed the effects of a plant-derived biostimulant (PDB, Bioup (R) TF) on fruit quality and composition of two greenhouse cherry tomato cultivars (Caravaggio and Creativo) grown during the autumn-winter. The biostimulant application enhanced the marketable fruit yield up to 1.148 g m(-2) of 'Creativo' (+16 %) and increased the fruit dry matter, firmness, and chroma (C*), particularly of 'Caravaggio' (by 23, 12, and 11 %, respectively). 'Caravaggio' also showed the strongest increase in total polyphenols (+26 %) and carotenoid contents (+50 %) in response to the treatment. This trend paralleled the strongest rise of the in vitro antioxidant activity of its fruit extracts, as revealed by the DPPH and FRAP assays. Moreover, the biostimulant treatment resulted in higher concentrations of 10 among 12 minerals analyzed in fresh fruit. This effect was particularly relevant for calcium, manganese, and copper, whereas 'Caravaggio' proved the strongest rise for potassium, magnesium, sodium, and zinc. Interestingly, the biostimulant application did not promote or even reduced the concentration of nickel in fresh 'Caravaggio' and 'Creativo' (-38 %) fruit, respectively. This suggests that the integration of PDBs in the framework of agronomic strategies could assist in producing Ni-poor tomatoes while increasing, at the same time, their levels in health-promoting minerals.
Anthocyanin profiles of juices from blueberry (Vaccinium myrtillus L.) and different grape varieties (Vitis labrusca L. cv. Concord, Vitis vinifera L. cvs. Accent, Dunkelfelder, Dakapo, and GM 674-1) were characterized by ultrahigh performance liquid chromatography (UHPLC) coupled to trapped ion mobility spectrometry-quadrupole time-of-flight tandem mass spectrometry (TIMS-QTOF-MS/MS). Ion mobility and collision cross section (CCS) values of over 50 structurally related anthocyanins based on delphinidin, cyanidin, petunidin, peonidin, and malvidin were determined. Relations between molecular mass, mobility values, and specific structural features were revealed. The mass-to-charge (m/z) ratio of the molecular ions (M+) was found to be the major factor influencing anthocyanin ion mobilities, but structural characteristics also contributed to their variability. We were able to differentiate positional and geometrical isomers and certain epimers by their respective mobility values. For instance, whereas 3-O-hexosides (i.e., 3-O-glucosides and 3-O-galactosides) were separated by TIMS, epimers of 3-O-pentosides assessed could not be distinguished.
Pharmaceutical, cosmetic, and agricultural applications of bioactive stilbenoids are limited due to their poor photostability. We aimed to modulate the photostability of (E)-resveratrol in grape cane extract formulations by supplementation with selected additives and monitoring (E)- and (Z)-resveratrol concentrations by HPLC-DAD during 4 h of exposure to artificial sunlight. (E)-Resveratrol in liquid formulations degraded to ca. 13% (0.005 mmol/L) of its initial content (0.040 mmol/L) during the aforementioned illumination (reaction constant k = 0.54 1/h). Deceleration of (E)-resveratrol light-decay was most pronounced when supplemented with dispersible zinc oxide (k = 0.11) or a phenolic apple extract (k = 0.16). In the dried thin-film state, phenolic apple extract (k = 0.08) and zinc oxide (k = 0.12) significantly enhanced the photostability of (E)-resveratrol (control: k = 0.19). Overall, (Z)-resveratrol development was less pronounced than (E)-resveratrol decay, indicating reactions beyond E/Z-isomerization. Briefly, the addition of apple polyphenols or zinc oxide at appropriate dosages was shown to significantly enhance the photostability of (E)-resveratrol in grape cane extract formulations.
BACKGROUND Organic viticulture seeks sustainable alternatives for eco-toxic copper fungicides to control downy mildew caused by Plasmopara viticola. (Poly)phenol-rich extracts of agricultural byproducts are known to possess antifungal activity, but high production costs often limit their actual implementation. RESULTS Herein, we developed and produced novel ligninsulfonate-based grape cane extract formulations and an apple extract on pilot plant scale, including a detailed (poly)phenol characterization by HPLC-PDA-MS. Our grape cane extract formulations alone reduced downy mildew disease severity in greenhouse trials by 29-69% in a dose-dependent manner, while a standard application of the copper-based agent alone reached ca. 56%. When applied together, disease severity was diminished by 78-92%, revealing a synergistic effect that depended on the mixture ratio. Combining grape cane formulations with the apple extract, additive effects were found (80% disease severity reduction). CONCLUSION The studied plant extracts are proposed to both substitute for and synergistically reinforce copper fungicides in grapevine downy mildew control. This article is protected by copyright. All rights reserved.
Volatiles, descriptive sensory profiles as well as consumer acceptance and preference of juices from red-fleshed ‘Weirouge’ apples produced in 2019 and 2020 with three different dejuicing systems were assessed. HS–SPME–GC–MS analyses revealed differences in the profiles of volatiles in juices processed in an oxygen-reduced atmosphere with an innovative spiral filter press as compared to those obtained using conventional systems, i.e., horizontal filter press and decanter. A total of 49 volatiles was tentatively assigned and permitted a clustering of the samples according to vintage and processing technology by multivariate statistics. Tentative markers to differentiate the individual samples were deduced from the multivariate models. In both years, each three 1,3-dioxanes and C 6 alcohols were revealed as discriminative markers of horizontal filter pressed juices. Descriptive sensory analysis by trained panelists revealed higher intensity scores of ‘oxidized’ and ‘apple-like’ orthonasal odors in juices produced by horizontal filter press and decanter as compared to those obtained by spiral filter press. The visual appearance of the spiral filter pressed juices was significantly higher rated compared to those obtained by conventional pressing systems as revealed by an untrained consumer panel ( n = 65). In contrast, both odor and taste were lower rated, ultimately resulting in a clear-cut higher acceptance and preference of the decanter-made juices, followed by those obtained by horizontal and spiral filter press.
The comprehensive identification of the proteome content from a white wine (cv. Silvaner) is described here for the first time. The wine protein composition isolated from a representative wine sample (250 L) was identified via mass spectrometry (MS)-based proteomics following in-solution and in-gel digestion methods after being submitted to size exclusion chromatographic (SEC) fractionation to gain a comprehensive insight into proteins that survive the vinification processes. In total, we identified 154 characterized (with described functional information) or so far uncharacterized proteins, mainly from Vitis vinifera L. and Saccharomyces cerevisiae. With the complementarity of the two-step purification, the digestion techniques and the high-resolution (HR)-MS analyses provided a high-score identification of proteins from low to high abundance. These proteins can be valuable for future authentication of wines by tracing proteins derived from a specific cultivar or winemaking process. The proteomics approach presented herein may also be generally helpful to understand which proteins are important for the organoleptic properties and stability of wines.
In the European Union, organic viticulture faces enormous challenges in controlling grapevine downy mildew since the ban on inorganic phosphonates or phosphonic acid in 2013. However, inorganic phosphonate is still detected in organic wines, although the responsible winegrowers often pledge that they had not sprayed phosphonate-containing products in their vineyards. Among several hypotheses on the origin, the emergence of phosphonate from the soil, e.g., due to preceding applications or from contaminated groundwater, is in dis-cussion. This study investigates whether an analytical differentiation of the origin of phosphonate in the plant or the final product might be feasible by examining leaf and petiole tissue. A total of 908 leaf and petiole samples of various grapevine cultivars were collected from a container vine experiment as well as from four experimental vineyard sites in Germany, on which phosphonate was either sprayed onto the plants as part of crop protection (all experiments), applied to the soil (container experiment only) or present as residue from previous applications (vineyard experiments). Phosphonate concentrations in leaves and petioles depended strongly on whether plants had been sprayed or had taken up phosphonate from the soil. Therefore, an index was created and tested using independent datasets from different geographical locations, based on the concentrations found in leaves and petioles. Index accuracy was at 99.1% correct classifications when distinguishing phosphonate origin from the soil versus that from foliar spraying. Furthermore, phosphonate uptake from the soil was shown to allow considerable phosphonate concentrations in the berries and musts, rendering associations of phosphonate resi-dues in wines with accusations of an actual foliar application highly questionable. In brief, our data and index might provide an approach for identifying the source of phosphonate contamination in the grapevine plant and, if suitable sample material is available, also the related products.
Anthocyanins in red cabbage, sweet potato, and Tradescantia pallida leaves were characterised. A total of 18 non-, mono-, and diacylated cyanidins was identified in red cabbage by high performance liquid chromatography-diode array detection coupled to high-resolution and multi-stage mass spectrometry. Sweet potato leaves contained 16 different cyanidin- and peonidin glycosides being predominantly mono- and diacylated. In T. pallida leaves, the tetra-acylated anthocyanin tradescantin prevailed. The large proportion of acylated anthocyanins resulted in a superior thermal stability during heating of aqueous model solutions (pH 3.0) coloured with red cabbage and purple sweet potato extracts as compared to that of a commercial Hibiscus-based food dye. However, their stability was still outperformed by that of the most stable Tradescantia extract. Comparing vis spectra from pH 1-10, the latter had an additional, uncommon absorption maximum at approx. 585 nm at slightly acidic to neutral pH values, yielding intensely red to purple colours.
Phenolic compounds from two black chokeberry cultivars 'Viking' and 'Nero' grown in Turkey were analyzed by high performance liquid chromatography-diode array detection-electrospray ionization-multistage mass spectrometry (HPLC-DAD-ESI-MSn). In the first step, five different solvents were compared to efficiently isolate phenolic compounds by ultrasound-assisted extraction. Three sequential extraction cycles using methanol/formic acid (95:5, v/v) sufficed for exhaustive extraction of anthocyanins, hydroxycinnamic acid derivatives, and flavonol glycosides from black chokeberry within merely 60 sec. A total of four cyanidin glycosides, two hydroxycinnamic acids, and five quercetin mono- and diglycosides were detected in both cultivars. Total anthocyanins (425-438 mg/100 g of fresh weight, FW), hydroxycinnamic acids (173-179 mg/100 g of FW), and flavonols (37 mg/100 g of FW) were determined in a similar range for both cultivars. Complementary, a rapid ultra-high performance liquid chromatography (UHPLC)-DAD method was developed, permitting a high throughput screening of chokeberry phenolics. The established methods were validated considering extraction recoveries, intra- and inter-day repeatability, calibration linearity, limit of detection (LOD), and limit of quantitation (LOQ). UHPLC provided a 2.3 times faster compound separation (30 min) and less solvent consumption than HPLC (68 min).
Coumarins, psoralens, and polymethoxyflavones have long been described as authenticity markers in lemon (Citrus limon [L.] Burm.f.) juices. However, the lack of quantitative concentration limits for these markers hampers the differentiation of natural variability and acceptable technical process variations from inacceptable lacks in good manufacturing practice (GMP) or even deliberate food fraud by, e.g., the addition of lime (Citrus x aurantifolia [Christm.] Swingle; Citrus x latifolia [Yu.Tanaka]) juice. In this study, a total of 139 lemon and lime samples, including fruits, juices, juice concentrates, and peel oils from eleven countries and covering all usual processing methods on the market, were analysed using three different liquid chromatographic methods of three different labs. First, we confirmed the considered analytical approaches to yield comparable results and analysed the results in detail per product type and processing technology. After carefully eliminating samples prone to authenticity doubts, we used the remaining dataset (125 samples) for establishing maximum concentration limits for coumarins, psoralens, and polymethoxyflavones for the differentiation of authentic lemon juices produced under GMP conditions, i.e., compliant with the AIJN Code of Practice, from adulterated products made with inacceptable procedures such as excessive co-extraction of flavedo or the admixture of non-lemon Citrus species, particularly lime.
Blackcurrant juices were produced with an oxygen-excluding spiral filter press and two conventional pressing systems exerting common oxygen exposure at pilot plant scale (200 kg) in technological duplicate in two subsequent years ( n = 4). In contrast to findings on previously studied fruits, contents of total and individual anthocyanins were not significantly higher after spiral filter (1636–1872 mg/L) than after conventional pressing (1529–2083 mg/L). During storage for 52 weeks at 4, 20 and 37 °C, anthocyanin levels depended strongly on storage temperature, but not on the used pressing system (conventional vs. oxygen-reduced). Other juice quality parameters like ascorbic acid behaved likewise. Furthermore, a D-optimal design of experiments was used to study the influence and interactions of the factors oxygen, ascorbic acid, sugar and pH value on anthocyanin levels during a heat treatment in a model solution made with preparatively isolated blackcurrant anthocyanins. In agreement with our production trials at pilot plant scale, oxygen levels were only marginally important for the rate of anthocyanin degradation, but the influence of sugar content, ascorbic acid content and pH value was highly relevant as discussed in this report.
Essential oils (EOs) and their individual volatile organic constituents have been an inherent part of our civilization for thousands of years. They are widely used as fragrances in perfumes and cosmetics and contribute to a healthy diet, but also act as active ingredients of pharmaceutical products. Their antibacterial, antiviral, and anti-inflammatory properties have qualified EOs early on for both, the causal and symptomatic therapy of a number of diseases, but also for prevention. Obtained from natural, mostly plant materials, EOs constitute a typical example of a multicomponent mixture (more than one constituent substances, MOCS) with up to several hundreds of individual compounds, which in a sophisticated composition make up the property of a particular complete EO. The integrative use of EOs as MOCS will play a major role in human and veterinary medicine now and in the future and is already widely used in some cases, e.g., in aromatherapy for the treatment of psychosomatic complaints, for inhalation in the treatment of respiratory diseases, or topically administered to manage adverse skin diseases. The diversity of molecules with different functionalities exhibits a broad range of multiple physical and chemical properties, which are the base of their multi-target activity as opposed to single isolated compounds. Whether and how such a broad-spectrum effect is reflected in natural mixtures and which kind of pharmacological potential they provide will be considered in the context of ONE Health in more detail in this review.
Stilbenoids in grape cane (Vitis vinifera L.) are bioactive compounds relevant for plant defense and the potential valorization of this byproduct. Our screening of grape cane from 102 varieties showed constitutive stilbenoid levels in a wide range (557-7748 mg/kg of dry weight). Analyses of genetically distinct clones of selected cultivars unraveled that intravarietal variability (e.g., cv. Riesling, 3236-6541 mg/kg) was higher than that across samples from a single clone but different vineyard positions (3017-3710 mg/kg). Furthermore, stilbenoid levels in samples obtained in October, December, and February (3 years, 2017-2019) showed pronounced quantitative and qualitative variability and the highest yields upon December pruning. For instance, vitisin B and ε-viniferin in cv. Pinot Noir and Accent were predominant in 2017 and 2019 (both >90% of total stilbenoids) but not in 2018 (both <55%) when temperatures were high and precipitation low. In brief, we report the variability of stilbenoid levels in grape cane depending upon genetic and environmental factors.