Dietary, socioeconomic, and maize handling practices associated with aflatoxin and fumonisin exposure among women tortilla makers in 5 departments in Guatemala.

Previous research has demonstrated human exposure to mycotoxins among Guatemalans, with high levels of mycotoxins being found in blood and urine samples as well as in maize for human consumption. Mishandling of crops such as maize during pre- and post-harvest has been associated with mycotoxin contamination. The overarching goal of this study was to identify risk factors for aflatoxin and fumonisin exposure in Guatemala. A cross-sectional survey of 141 women tortilla makers was conducted in the departments of Guatemala, Sololá, Suchitepéquez, Izabal, and Zacapa in February 2022. Maize and tortilla samples were collected and analyzed for aflatoxin B1 (AFB1) and fumonisin B1, B2, and B3 contamination (FB1, FB2, FB3). Urine samples were collected and analyzed for urinary FB1 (uFB1) contamination. A questionnaire was administered to collect data on sociodemographic characteristics, dietary intake of maize-based foods the week prior to the study, and maize handling practices. Descriptive statistics were used to describe common maize handling practices. A univariable analysis was conducted to identify predictors of low/high AFB1, total fumonisins, and uFB1. Multivariable logistic regression was used to calculate adjusted odds ratios (ORs) and 95% confidence intervals (CIs). During tortilla processing, a reduction in the AFB1 and total fumonisin levels was observed. The presence of AFB1 in maize was associated with department and mean total fumonisin level in maize (OR: 1.705, 95% CI: 1.113-2.613). The department where the tortilleria was located was significantly associated with the presence of fumonisins in tortillas. Increased consumption of Tortrix was significantly associated with the presence of FB1 in urine (OR: 1.652, 95% CI: 1.072-2.546). Results of this study can be used in the development and implementation of supply chain management practices that mitigate mycotoxin production, reduce food waste and economic loss, and promote food security.

Nondestructive and Rapid Screening of Aflatoxin-Contaminated Single Peanut Kernels Using Field-Portable Spectroscopy Instruments (FT-IR and Raman).

A nondestructive and rapid classification approach was developed for identifying aflatoxin-contaminated single peanut kernels using field-portable vibrational spectroscopy instruments (FT-IR and Raman). Single peanut kernels were either spiked with an aflatoxin solution (30 ppb-400 ppb) or hexane (control), and their spectra were collected via Raman and FT-IR. An uHPLC-MS/MS approach was used to verify the spiking accuracy via determining actual aflatoxin content on the surface of randomly selected peanut samples. Supervised classification using soft independent modeling of class analogies (SIMCA) showed better discrimination between aflatoxin-contaminated (30 ppb-400 ppb) and control peanuts with FT-IR compared with Raman, predicting the external validation samples with 100% accuracy. The accuracy, sensitivity, and specificity of SIMCA models generated with the portable FT-IR device outperformed the methods in other destructive studies reported in the literature, using a variety of vibrational spectroscopy benchtop systems. The discriminating power analysis showed that the bands corresponded to the C=C stretching vibrations of the ring structures of aflatoxins were most significant in explaining the variance in the model, which were also reported for Aspergillus-infected brown rice samples. Field-deployable vibrational spectroscopy devices can enable in situ identification of aflatoxin-contaminated peanuts to assure regulatory compliance as well as cost savings in the production of peanut products.

Portable Mid-Infrared Spectroscopy Combined with Chemometrics to Diagnose Fibromyalgia and Other Rheumatologic Syndromes Using Rapid Volumetric Absorptive Microsampling.

The diagnostic criteria for fibromyalgia (FM) have relied heavily on subjective reports of experienced symptoms coupled with examination-based evidence of diffuse tenderness due to the lack of reliable biomarkers. Rheumatic disorders that are common causes of chronic pain such as rheumatoid arthritis, systemic lupus erythematosus, osteoarthritis, and chronic low back pain are frequently found to be comorbid with FM. As a result, this can make the diagnosis of FM more challenging. We aim to develop a reliable classification algorithm using unique spectral profiles of portable FT-MIR that can be used as a real-time point-of-care device for the screening of FM. A novel volumetric absorptive microsampling (VAMS) technique ensured sample volume accuracies and minimized the variation introduced due to hematocrit-based bias. Blood samples from 337 subjects with different disorders (179 FM, 158 non-FM) collected with VAMS were analyzed. A semi-permeable membrane filtration approach was used to extract the blood samples, and spectral data were collected using a portable FT-MIR spectrometer. The OPLS-DA algorithm enabled the classification of the spectra into their corresponding classes with 84% accuracy, 83% sensitivity, and 85% specificity. The OPLS-DA regression plot indicated that spectral regions associated with amide bands and amino acids were responsible for discrimination patterns and can be potentially used as spectral biomarkers to differentiate FM and other rheumatic diseases.

Metabolic Fingerprinting for the Diagnosis of Clinically Similar Long COVID and Fibromyalgia Using a Portable FT-MIR Spectroscopic Combined with Chemometrics.

Post Acute Sequelae of SARS-CoV-2 infection (PASC or Long COVID) is characterized by lingering symptomatology post-initial COVID-19 illness that is often debilitating. It is seen in up to 30-40% of individuals post-infection. Patients with Long COVID (LC) suffer from dysautonomia, malaise, fatigue, and pain, amongst a multitude of other symptoms. Fibromyalgia (FM) is a chronic musculoskeletal pain disorder that often leads to functional disability and severe impairment of quality of life. LC and FM share several clinical features, including pain that often makes them indistinguishable. The aim of this study is to develop a metabolic fingerprinting approach using portable Fourier-transform mid-infrared (FT-MIR) spectroscopic techniques to diagnose clinically similar LC and FM. Blood samples were obtained from LC (n = 50) and FM (n = 50) patients and stored on conventional bloodspot protein saver cards. A semi-permeable membrane filtration approach was used to extract the blood samples, and spectral data were collected using a portable FT-MIR spectrometer. Through the deconvolution analysis of the spectral data, a distinct spectral marker at 1565 cm-1 was identified based on a statistically significant analysis, only present in FM patients. This IR band has been linked to the presence of side chains of glutamate. An OPLS-DA algorithm created using the spectral region 1500 to 1700 cm-1 enabled the classification of the spectra into their corresponding classes (Rcv > 0.96) with 100% accuracy and specificity. This high-throughput approach allows unique metabolic signatures associated with LC and FM to be identified, allowing these conditions to be distinguished and implemented for in-clinic diagnostics, which is crucial to guide future therapeutic approaches.

High yield production of cyanidin-derived pyranoanthocyanins using 4-vinylphenol and 4-vinylguaiacol as cofactors.

Pyranoanthocyanins are anthocyanin-derived pigments with vivid colors and enhanced stability, making them promising food colorants. We evaluated two 4-vinylphenols, decarboxylated p-coumaric (pCA) and ferulic acid (FA), as cofactors for pyranoanthocyanin formation. Cyanidin-3-glycosides from saponified black carrot were incubated with 4-vinylphenol or 4-vinylguaiacol in different anthocyanin-to-cofactor molar ratios (1:1-1:30) to form pyranoanthocyanins. Formation efficiency (45 °C, ≤96 h) was compared to their respective precursors at a 1:30 ratio. Composition changes were monitored using uHPLC-PDA-ESI-MS/MS. Pyranoanthocyanin yields with 4-vinylphenol (13.8-33.4%) were ∼12× higher than with pCA and yields with 4-vinylguaiacol (8.1-31.0%) were ∼6.5× higher than with FA. Molar ratios of 1:5 and 1:10 yielded significantly more pyranoanthocyanins. Pyranoanthocyanin formation with 4-vinylphenols followed first-order kinetics, whereas formation with hydroxycinnamic acids followed zero-order kinetics. Detection of intermediate compounds was consistent with a nucleophilic addition and aromatization formation mechanism. Overall, pyranoanthocyanin formation with 4-vinylphenols was more efficient than with hydroxycinnamic acids.

Screening for pesticide residues in cocoa (Theobroma cacao L.) by portable infrared spectroscopy.

Rapid assessment of pesticide residues ensures cocoa bean quality and marketability. In this study, a portable FTIR instrument equipped with a triple reflection attenuated total reflectance (ATR) accessory was used to screen cocoa beans for pesticide residues. Cocoa beans (n = 75) were obtained from major cocoa growing regions of Peru and were quantified for pesticides by gas chromatography (GC) or liquid chromatography (LC) coupled with mass spectrometry (MS). The FTIR spectra were used to detect the presence of pesticides in cocoa beans or lipid fraction (butter) by using a pattern recognition (Soft Independent Modeling by Class Analogy, SIMCA) algorithm, which produced a significant discrimination for cocoa nibs (free or with pesticides). The variables related to the class grouping were assigned to the aliphatic (3200-2800 cm-1) region with an interclass distance (ICD) of 3.3. Subsequently, the concentration of pesticides in cocoa beans was predicted using a partial least squares regression analysis (PLSR), using an internal validation of the PLRS model, the cross-validation correlation coefficient (Rval = 0.954) and the cross-validation standard error (SECV = 14.9 mg/kg) were obtained. Additionally, an external validation was performed, obtaining the prediction correlation coefficient (Rpre = 0.940) and the standard error of prediction (SEP = 16.0 µg/kg) with high statistical performances, which demonstrates the excellent predictability of the PLSR model in a similar real application. The developed FTIR method presented limits of detection and quantification (LOD = 9.8 µg/kg; LOQ = 23.1 µg/kg) with four optimum factors (PC). Mid-infrared spectroscopy (MIR) offered a viable alternative for field screening of cocoa.

Thermal stability comparison between 10-catechyl-pyranoanthocyanins and anthocyanins derived from pelargonidin, cyanidin, and malvidin.

10-Catechyl-pyranoanthocyanins are pigments derived from nature formed by reacting an anthocyanin with caffeic acid. Here, we compared the thermal stability and formed degradation compounds of different 10-catechyl-pyranoanthocyanins. Pelargonidin-3-glucoside, cyanidin-3-glucoside, malvidin-3-glucoside, anthocyanins differing in the number of substitutions on the B-ring, and their corresponding 10-catechyl-pyranoanthocyanins were heated at 90 °C for 4.5 h at pH 3. Anthocyanin's color faded (ΔELab > 5) after only 0.5 h, and absorbance at λvis-max decreased by > 64 % after 4.5 h, with cyanidin-3-glucoside being the most stable. In contrast, 10-catechyl-pyranoanthocyanins color was heat stable (ΔELab < 5) with absorbance at λvis-max reduced by < 10 % after 4.5 h heating. A phenolic degradation compound formed in all samples, dependent on the parent pigment's B-ring substitutions. All 10-catechyl-pyranoanthocyanins produced the same colored degradation compound (λmax = 478 nm, m/z = 315), suggesting the B-ring was not attached. 10-Catechyl-pyranoanthocyanins displayed excellent thermal stability irrespective of the anthocyanin used for formation.

A novel handheld FT-NIR spectroscopic approach for real-time screening of major cannabinoids content in hemp.

A novel approach for rapid (15s) detection and quantification of predominant cannabinoids in hemp was developed using Fourier-transformed near-infrared spectroscopy (FT-NIR), enabling real-time and field-based applications. Hemp samples (n = 91) were obtained from certified online vendors, the OARDC Weed Lab, and a local Ohio farm. Reference data of major cannabinoids content were determined by uHPLC-MS/MS. Spectral data were collected by a miniaturized, battery-operated FT-NIR instrument, and combined with the reference data to generate partial least squares regression (PLSR) models. uHPLC-MS/MS analysis showed two samples had over 0.36% of Δ9-tetrahydrocannabinol (Δ9-THC), and 64% (32 out of 50) of online-bought hemp samples were not in compliance with their total cannabidiol (CBD) content declaration. PLSR prediction models showed excellent correlation (Rpre = 0.91-0.95) and a low standard error of prediction (SEP = 0.02-0.61%). This method could be used as an alternative to traditional methods for in-situ assessment of hemp quality.

Analyzing the Interaction between Anthocyanins and Native or Heat-Treated Whey Proteins Using Infrared Spectroscopy.

The color stability of anthocyanins (ACN) has been shown to be improved by interaction with whey proteins (WP). In this study, we explore the ACN-WP interaction using Fourier transform infrared spectroscopy (IR). ACN from purple corn, grape, and black carrot (50 µM) were evaluated. IR spectra (4000-700 cm-1) were collected for native and preheated (40-80 °C) WP (5 mg/mL) and ACN-WP mixtures at pH 7.4. Soft independent modeling of class analogy was used to analyze the IR data. The WP secondary structure changed after heat treatments and after interaction with ACN. As expected, the WP α-helices decreased, and ß-sheet increased after heat treatment. The intensities of the WP amide I and II bands decreased after ACN addition, revealing a decrease in the WP α-helix content. Higher preheating temperatures (70-80 °C) resulted in a more disordered WP structure that favored stronger WP-ACN interactions related to amide III changes. Addition of ACN stabilized WP structure due to heat denaturation, but different ACN structures had different binding affinities with WP. WP structure had less change after interaction with ACN with simpler structures. These results increase our understanding of ACN-WP interactions, providing a potential strategy to extend anthocyanin color stability by WP addition.

Comparing the thermal stability of 10-carboxy-, 10-methyl-, and 10-catechyl-pyranocyanidin-3-glucosides and their precursor, cyanidin-3-glucoside.

Pyranoanthocyanins are vibrant, naturally derived pigments formed by the reaction of an anthocyanin with a cofactor containing a partially negatively charged carbon. This study compared the thermal stability and degradation products of 10-carboxy-pyranocyanidin-3-glucoside (pyruvic acid cofactor), 10-methyl-pyranocyanidin-3-glucoside (acetone cofactor), and 10-catechyl-pyranocyanidin-3-glucoside (caffeic acid cofactor) with their anthocyanin precursor to evaluate the role of the pyranoanthocyanin C10 substitution on stability. Pyranoanthocyanins exhibited absorbance half-lives ~2.1-8.6 times greater than cyanidin-3-glucoside, with ~15-52% of their original pigment remaining after 12 h of 90 °C heating at pH 3.0. 10-Methyl-pyranocyanidin-3-glucoside was the most stable (p < 0.01) based on UHPLC-PDA analysis, while 10-catechyl-pyranocyanidin-3-glucoside had the most stable color in part due to contribution from a colored degradation compound. Protocatechuic acid formed in all heated samples, which suggested a similar degradation mechanism among pigments. In conclusion, the C10 substitution impacted the extent of pyranoanthocyanin stability and the degradation compounds formed.

Influence of the Anthocyanin and Cofactor Structure on the Formation Efficiency of Naturally Derived Pyranoanthocyanins.

Pyranoanthocyanins are anthocyanin-derived pigments with higher stability to pH and storage. However, their slow formation and scarcity in nature hinder their industrial application. Pyranoanthocyanin formation can be accelerated by selecting anthocyanin substitutions, cofactor concentrations, and temperature. Limited information is available on the impacts of the chemical structure of the cofactor and anthocyanin; therefore, we evaluated their impacts on pyranoanthocyanin formation efficiency under conditions reported as favorable for the reaction. Different cofactors were evaluated including pyruvic acid, acetone, and hydroxycinnamic acids (p-coumaric, caffeic, ferulic, and sinapic acid) by incubating them with anthocyanins in a molar ratio of 1:30 (anthocyanin:cofactor), pH 3.1, and 45 °C. The impact of the anthocyanin aglycone was evaluated by incubating delphinidin, cyanidin, petunidin, or malvidin derivatives with the most efficient cofactor (caffeic acid) under identical conditions. Pigments were identified using UHPLC-PDA and tandem mass spectrometry, and pyranoanthocyanin formation was monitored for up to 72 h. Pyranoanthocyanin yields were the highest with caffeic acid (~17% at 72 h, p < 0.05). When comparing anthocyanins, malvidin-3-O-glycosides yielded twice as many pyranoanthocyanins after 24 h (~20%, p < 0.01) as cyanidin-3-O-glycosides. Petunidin- and delphinidin-3-O-glycosides yielded <2% pyranoanthocyanins. This study demonstrated the importance of anthocyanin and cofactor selection in pyranoanthocyanin production.

The effect of whey protein concentration and preheating temperature on the color and stability of purple corn, grape and black carrot anthocyanins in the presence of ascorbic acid.

Our objective was to explore the effects of whey protein (WP) concentration and preheating temperature on anthocyanin color expression and stability over time in the presence of ascorbic acid. Anthocyanins from purple corn, grape or black carrot were mixed with native WP or preheated WP (40-80°C) in various concentrations (0-10 mg/mL) in pH 3 buffer containing 0.05% ascorbic acid and stored in the dark at 25 °C for 5 days. WP addition increased anthocyanin absorbance and protected anthocyanin from ascorbic acid-mediated degradation. Increasing WP concentration resulted in lower lightness and higher chroma, hue angle and color stability. The color loss of anthocyanin solutions decreased by 40%-50% when 10 mg/mL WP was added. Native WP showed more color enhancement and protection than thermally-induced WP. Increasing the WP preheating temperature resulted in less absorbance increase and more absorbance loss. Anthocyanin' half-life was improved by addition of WP in a dose dependent manner. Native WP addition (10 mg/mL) extended anthocyanin half-life by about 2 times for purple corn and grape, and 1.31 times for black carrot anthocyanin solutions. Preheating temperature did not significantly affect anthocyanin protection by WP. WP addition might enhance anthocyanin stability in beverages containing ascorbic acid, expanding anthocyanin application in foods.

Acylated Anthocyanins from Red Cabbage and Purple Sweet Potato Can Bind Metal Ions and Produce Stable Blue Colors.

Red cabbage (RC) and purple sweet potato (PSP) are naturally rich in acylated cyanidin glycosides that can bind metal ions and develop intramolecular π-stacking interactions between the cyanidin chromophore and the phenolic acyl residues. In this work, a large set of RC and PSP anthocyanins was investigated for its coloring properties in the presence of iron and aluminum ions. Although relatively modest, the structural differences between RC and PSP anthocyanins, i.e., the acylation site at the external glucose of the sophorosyl moiety (C2-OH for RC vs. C6-OH for PSP) and the presence of coordinating acyl groups (caffeoyl) in PSP anthocyanins only, made a large difference in the color expressed by their metal complexes. For instance, the Al3+-induced bathochromic shifts for RC anthocyanins reached ca. 50 nm at pH 6 and pH 7, vs. at best ca. 20 nm for PSP anthocyanins. With Fe2+ (quickly oxidized to Fe3+ in the complexes), the bathochromic shifts for RC anthocyanins were higher, i.e., up to ca. 90 nm at pH 7 and 110 nm at pH 5.7. A kinetic analysis at different metal/ligand molar ratios combined with an investigation by high-resolution mass spectrometry suggested the formation of metal-anthocyanin complexes of 1:1, 1:2, and 1:3 stoichiometries. Contrary to predictions based on steric hindrance, acylation by noncoordinating acyl residues favored metal binding and resulted in complexes having much higher molar absorption coefficients. Moreover, the competition between metal binding and water addition to the free ligands (leading to colorless forms) was less severe, although very dependent on the acylation site(s). Overall, anthocyanins from purple sweet potato, and even more from red cabbage, have a strong potential for development as food colorants expressing red to blue hues depending on pH and metal ion.

Monitoring the Interaction between Thermally Induced Whey Protein and Anthocyanin by Fluorescence Quenching Spectroscopy.

The color stability of anthocyanins was shown to improve with addition of whey proteins (WP). The goal of this study was to investigate the binding mechanisms of purple corn, grape and black carrot anthocyanin extracts to native and preheated WP (40-80 °C, 3.6 µM) at a pH of 3 using fluorescence quenching spectroscopy. The fluorescence spectra were collected with an excitation wavelength of 280 nm at 25 °C, 35 °C and 45 °C. The quenching data were analyzed by using the Stern-Volmer equation. The fluorescence intensity of WP decreased (up to 73%) and its λmax increased (by ~5 nm) with increasing anthocyanin concentration (0-100 µM). The quenching data showed that the interaction between anthocyanin extracts and WP was a static quenching process. Thermodynamic analysis showed their binding was mainly through hydrophobic interactions. Their binding affinity was higher for preheated WP than native WP and decreased gradually with increasing preheating temperature. Black carrot anthocyanin extract had the lowest binding affinity with WP, likely due to the larger molecular structure. These results help better understand the protection mechanism of native and preheated WP on anthocyanin color stability, expanding the application of anthocyanins as food colorants that better withstand processing and storage.

Pyranoanthocyanin formation rates and yields as affected by cyanidin-3-substitutions and pyruvic or caffeic acids.

Anthocyanin-derived pyranoanthocyanins (PACNs) offer potential as food colorants as they may exhibit higher stability than anthocyanins (ACNs). Our objective was to compare PACN formation rate and efficiency from different cyanidin-3-derivatives and cofactors, in order to facilitate PACN production. Four cyanidin-3-derivatives (cyanidin-3-glucoside, cyanidin-3-xylosylglucosylgalactoside, cyanidin-3-malonylglucoside and cyanidin-3-xylosyl(sinapoylglucosyl)galactoside) were incubated with pyruvic or caffeic acids (PA, CA) at 25 °C in the dark for two months. PACN formation was monitored by uHPLC-PDA-MS/MS over time. ACNs incubated with PA produced PACNs with yields increasing steadily over time, reaching 15% after 2 months. PACN formation with CA increased exponentially from the start, reaching 85% during storage. PACNs were efficiently produced from 3 of the 4 ACNs in the presence of CA, with minimal pigment loss. Copigmentation between CA and ACNs may facilitate PACN formation by keeping reactants in close proximity. Anthocyanin glycosylation and acylation affected PACN formation to a lower degree than cofactors.

Improvement of Naturally Derived Food Colorant Performance with Efficient Pyranoanthocyanin Formation from Sambucus nigra Anthocyanins Using Caffeic Acid and Heat.

Consumers and regulations encourage the use of naturally derived food colorants. Anthocyanins (ACN), plant pigments, are unstable in foods. In aged red wines, ACN with a free hydroxyl group at C-5 condenses to form pyranoanthocyanins (PACN), which are more stable but form inefficiently. This study attempted to produce PACN efficiently using high cofactor concentration and heat. Elderberry anthocyanins were semi-purified and caffeic acid (CA) was dissolved in 15% ethanol and diluted with a buffer to achieve ACN:CA molar ratios of 1:50, 1:100, 1:150, and 1:200, then incubated at 65 °C for 5 days. The effect of temperature was tested using ACN samples incubated with or without CA at 25 °C, 50 °C, and 75 °C for 7 days. Compositional changes were monitored using uHPLC-PDA-MS/MS. Higher CA levels seemed to protect pigment integrity, with ACN:CA 1:150 ratio showing the highest tinctorial strength after 48 h. PACN content growth was fastest between 24 and 48 h for all ACN:CA ratios and after 120 h, all ACN had degraded or converted to PACN. PACN formed faster at higher temperatures, reaching ~90% PACN in 24 h and ~100% PACN in 48 h at 75 °C. These results suggest that PACN can form efficiently from elderberry ACN and CA if heated to produce more stable pigments.

Accumulation of Anthocyanins and Other Phytochemicals in American Elderberry Cultivars during Fruit Ripening and its Impact on Color Expression.

American elderberry (Sambucus canadensis) is a plant native to North America with anthocyanin-rich fruits. Our objective was to investigate the effects of cultivar and ripeness on the phytochemical characteristics of its fruits and the corresponding color performance. Cultivars 'Adams', 'Johns', 'Nova', 'Wyldewood', and 'York' were examined for their °Brix, pH, anthocyanin (pH-differential method), and phenolic content (Folin-Ciocalteau method). Extract composition were analyzed by uHPLC-PDA-MS/MS. Color and spectra were determined using a plate reader. All characteristics evaluated were significantly affected by ripeness and cultivar, except for °Brix and total phenolic content, which did not vary significantly among cultivars. Most anthocyanins (63-72%) were acylated with p-coumaric acid, with cyanidin-3-(trans)-coumaroylsambubioside-5-glucoside the most predominant. The proportion of acylated anthocyanins was the only characteristic evaluated that decreased during ripening (from 80 to 70%). Extract from fully-ripened fruits exhibited red (lvis-max ~520 nm) and blue hues (lvis-max ~600 nm) at acidic and alkaline pH, respectively. Extracts from half-ripe fruit rendered yellowish tones and overall dull color. C-18 semi-purified extracts displayed higher color saturation (smaller L* and larger C*ab) than crude extracts. The vibrant and broad color expression of fully-ripened fruit extract, especially after C-18 purification, suggests this North American native plant as a promising natural colorant source.

Copigmentation with Chlorogenic and Ferulic Acid Affected Color and Anthocyanin Stability in Model Beverages Colored with Sambucus peruviana, Sambucus nigra, and Daucus carota during Storage.

The food industry is looking for alternatives to synthetic colorants. Anthocyanins (ACNs) are suitable replacements due to their color characteristics and potential health benefits. The application of sauco (Sambucus peruviana, SP) as a potential source of ACN-based colorants was evaluated and compared to elderberry (Sambucus nigra, SN) and an extract from purple carrots (PC). Color and pigment stability were evaluated using a model beverage system during eight weeks of storage. Copigmentation with chlorogenic acid (CGA) and ferulic acid (FA) were also evaluated. SP ACNs provided darker and more intense colors than those obtained with SN but less intense than those obtained with PC. Addition of CGA and FA resulted in significantly darker colors with higher chroma in beverages colored with SP and SN but not in beverages colored with PC. Copigmentation with FA reduced monomeric pigment half-lives for all ACN sources but increased the chroma half-lives of beverages colored with SP and SN, from 23 to 49 weeks, and from 23 to 55 weeks, respectively. Analyses using liquid chromatography coupled to photodiode array detection and mass spectrometry showed that interaction between non-acylated ACNs and FA resulted in the formation of pyranoanthocyanins. Overall, ACNs from non-acylated sources such as SP, in combination with FA, showed potential for commercial food applications.

Metal Chelates of Petunidin Derivatives Exhibit Enhanced Color and Stability.

Anthocyanins with catechol (cyanidin) or pyrogallol (delphinidin) moieties on the B-ring are known to chelate metals, resulting in bluing effects, mainly at pH ≤ 6. Metal interaction with petunidin, an O-methylated anthocyanidin, has not been well documented. In this study, we investigated metal chelation of petunidin derivatives in a wide pH range and its effects on color and stability. Purple potato and black goji extracts containing >80% acylated petunidin derivatives (25 µM) were combined with Al3+ or Fe3+ at 0 µM to 1500 µM in buffers of pH 3-10. Small metal ion concentrations triggered bathochromic shifts (up to ~80nm) at an alkaline pH, resulting in vivid blue hues (hab 200°-310°). Fe3+ caused a larger bathochromic shift than Al3+, producing green colors at pH 8-9. Generally, metal ions increased the color stability and half-life of petunidin derivatives in a dose-dependent manner, particularly at pH 8. Petunidin derivative metal chelates produced a wide range of colors with enhanced stability.

Growth of lactic acid bacteria in milk phospholipids enhances their adhesion to Caco-2 cells.

The mechanisms of bacterial adhesion to human cells involve several complex reactions and activation of genes and proteins. It has been reported that the food components in dairy matrices, such as sugar or salt, can decrease bacterial adhesion to Caco-2 cells. However, it has not been evaluated whether the bacteria grown in media supplemented with milk phospholipids (MPL) can increase or decrease the adhesion of these cells. The objective of this work was to evaluate the effects of MPL on the kinetic growth of lactic acid bacteria (LAB) and their functional characteristics as probiotics, expression of surface protein genes, and adherence to Caco-2 cells. Seven LAB strains isolated from various dairy products were characterized. Five of the tested LAB strains were able to grow in a chemically defined medium supplemented with MPL. Lactobacillus reuteri OSU-PECh-48 showed the highest growth rate and the greatest optical density. All of the strains tested showed tolerance to acidic conditions at pH 3.0 and to bile salts at 0.5 and 1% concentrations. Auto-aggregation and cell surface hydrophobicity ability were evaluated, with nonsignificant differences between the strains grown in MPL and without MPL. Gene expression of 6 surface proteins was evaluated in the presence or absence of MPL. Pediococcus acidilactici OSU-PECh-L and OSU-PECh-48 were the strains with highest relative expression of 5 of the 6 genes evaluated. Lactobacillus paracasei OSU-PECh-BA was the strain with the lowest level of expression of surface protein genes. Most of the bacteria tested had increased adhesion to Caco-2 cells after growth in MPL. The bacteria with the highest degrees of adhesion observed were Lactobacillus paracasei OSU-PECh-3B, Pediococcus acidilactici OSU-PECh-L, and Lactobacillus reuteri OSU-PECh-48. The genes Cnb and EF-Tu increased in expression in the presence of MPL in most of the LAB tested. The results obtained in this work demonstrate the high potential of these LAB strains for use as starters or beneficial cultures in fermentation of not only dairy products but also other food fermentation processes, with promising ability to increase residence time in the gut, modify the microbiome, and improve human health.