Hydrothermal Degradation of Rutin: Identification of Degradation Products and Kinetics Study

Distribution of active ingredients and quality control of Forsythia suspensa with AP-MALDI mass spectrometry imaging

The fruits of Forsythia suspensa (F. suspensa) have been used as a traditional Chinese medicine for 2000 years. Currently, the quality control of F. suspensa strictly follows the instructions of Chinese Pharmacopeia, which mainly controls the content of forsythoside A, phillyrin, and volatile oil. In this study, air pressure MALDI mass spectrometry imaging (AP-MALDI MSI) was used to evaluate the quality of F. suspensa fruits and the distribution of dozens of active ingredients. The variation of active ingredients was measured for more than 30 batches of samples, regarding harvest time, cultivated environment, shelf-life, and habitat. Fifty-three active ingredients could be detected in F. suspensa fruits with AP-MALDI MSI. Seven active ingredients were upregulated, four ingredients downregulated, and 15 ingredients did not change in ripe fruits. A sharp variation of active ingredients in late September was observed for the Caochuan fruits harvested in 2019, which is closely related to the appearance of the ginger color of the pericarp under the microscope observation. The microscope observation is a reliable way to classify ripe and green fruits instead of outlook. Just considering forsythoside A and phillyrin, it is found that wild fruits are better than cultivated fruits, but cultivated fruits have high contents of other ingredients. The shelf-life of F. suspensa fruits is proposed to be 3 years, considering the 26 ingredients investigated. It was found that Luoning wild fruits are better than those from Caochuan with a new evaluation method. Mass spectrometry imaging is an easy, objective, and effective method to evaluate the quality of F. suspensa fruits.

CO2-Sourced Polymer Dyes for Dual Information Encryption

Large amounts of small molecule dyes leak into the ecosystems annually in harmful and unsustainable ways. Polymer dyes have attracted much attention because of their high migration resistance, excellent stability, and minimized leakage. However, the complex synthesis process, high cost, and poor degradability hinder their widespread application. Herein, green and sustainable polymer dyes are prepared using natural dye quercetin (Qc) and CO2 through a one-step process. The CO2-sourced polymer dyes show strong migration resistance, high stability, and can be degraded on demand. Additionally, the CO2-sourced polymer dyes showed unique responses to Zn2+, leading to significantly enhanced fluorescence, highlighting their potential for information encryption/decryption. The CO2-sourced polymer dyes can solve the environmental hazards caused by small molecule dye leakage and promote the carbon cycle process. Meanwhile, the one-step synthesis process is expected to achieve sustainable and widespread utilization of CO2-sourced polymer dyes.

Investigation on the simultaneous inhibition of advanced glycation end products, 4-methylimidazole and hydroxymethylfurfural in thermal reaction meat flavorings by liquiritigenin, liquiritin and glycyrrhizic acid and possible pathways

The inhibitory effects of liquiritigenin, liquiritin and glycyrrhizic acid against the hazards during the preparation of thermal reaction beef flavoring were investigated using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Liquiritigenin(1.5 mM) inhibited Nε-carboxymethyl-L-lysine and Nε-carboxyethyl-L-lysine by up to 38.69 % and 61.27 %, respectively; 1.5 mM liquiritin inhibited 4-methylimidazole by up to 48.28 %; and 1.5 mM liquiritigenin and 1.0 mM liquiritin inhibited hydroxymethylfurfural by up to 61.20 % and 59.31 %, respectively. The results of the model system showed that the inhibitory effect of the 3 inhibitors could be extended to other thermal reaction flavoring systems. The 3 inhibitors can effectively block key intermediates in beef flavoring, and liquiritigenin can inhibit up to 22.97 % of glyoxal and 22.89 % of methylglyoxal. In addition, liquiritigenin and liquiritin can directly eliminate up to 25.87 % and 21.01 % of methylglyoxal by addition and other means. Free radicals in the simultaneous formation model system were measured using electron spin resonance (ESR), and the results showed that liquiritigenin, liquiritin and glycyrrhizic acid could scavenge free radicals in the system in a dose-dependent manner, with scavenging rates of up to 44.88-57.09 %. Therefore, the inhibitory effects of the 3 inhibitors can be attributed to the intermediate blocking and free radical scavenging pathways.

Hydrothermal treatment improves xanthine oxidase inhibitory activity and affects the polyphenol profile of Flos Sophorae Immaturus

BACKGROUND

Flos Sophorae Immaturus (FSI) is rich in polyphenols and a potential uric acid-lowering food. However, the processing of FSI is greatly restricted due to the heat sensitivity and low solubility of polyphenols. In this study, hydrothermal treatment - an effective strategy - was applied to FSI processing. The variation of xanthine oxidase (XO) inhibitory effect and polyphenol composition of FSI during hydrothermal treatment were recorded.

RESULTS

The XO inhibition rate of FSI increased from 32.42% to 89.00% after hydrothermal treatment at 220 °C for 30 min, as well as total polyphenols (from 0.66 to 1.11 mg mL^-1 ) and flavonoids (from 1.21 to 1.58 mg mL^-1 ). However, high thermal temperature (>160 °C) and extended thermal time (>90 min) caused the degradation of polyphenols. Rutin, kaempferol-3-O-rutinoside and narcissoside rapidly degraded and converted to quercetin, kaempferol and isorhamnetin when the temperature exceeded 160 °C. The maximum yields of quercetin, kaempferol and isorhamnetin were at 220 °C for 30 min, 90 min and 90 min, respectively. Meanwhile, the conversion kinetics conformed to the first-order model. Interestingly, these newly formed polyphenols possessed better XO inhibitory effects than their derivatives with 3-O-rutinoside.

CONCLUSION

Polyphenol conversion during hydrothermal treatment was the main reason for enhancing XO inhibitory activity. Therefore, hydrothermal treatment is an appropriate method for improving the XO inhibitory effect of FSI. © 2022 Society of Chemical Industry.

Influence of phenolic compounds on color formation at different stages of the VHP sugar manufacturing process

Phenolic compounds are natural dyes contained in sugarcane juice and represent an important parameter in industrial processing, as they significantly affect the color formation of raw sugar. This study investigated the relationship between color formation and phenolic compounds during a Very High Polarization (VHP) sugar manufacturing process, in which the RB92579 genotype represents about 50% of the processed sugarcane. The products evaluated during the industrial processing of sugarcane were: raw juice, mixed juice, lime-treated juice, clarified juice, syrup, massecuite, and VHP sugar. The polyphenols catechin (CAT), chlorogenic acid (CGA), caffeic acid (CAF), vanillin (VAN), syringaldehyde (SYR), p-coumaric acid (p-COU), coumarin (CUM), and rutin (RUT) were quantified by high-performance liquid chromatography (HPLC). The highest concentrations of CGA and SYR were obtained from the sucrose crystallization product (massecuite), similarly to the parameters of color, total phenols and the total polyphenol content. CGA was the predominant polyphenol in the samples of clarified juice, syrup, massecuite and VHP sugar, with the latter presenting concentrations above 50%. The presence of phenolic compounds provided different indices of color during the production process. In this context, chlorogenic acid (CGA) was the compound that presented the most expressive results, contributing significantly to the formation of color in sugarcane processing products, which is a fact that has not yet been reported in the literature. The color of the VHP sugar crystals also had a positive relationship with the concentration of phenolics, with greater evidence for CGA.

Stability of polyphenols in food processing

In recent years, polyphenols have attracted considerable attention due to their diverse potential health-beneficial effects on humans. Polyphenols are widely distributed in natural plants, and therefore play an important role in human food. Thermal processing, irradiation, fermentation, high pressure, microwave, and drying are several popular food processing methods. However, polyphenols are instable in food processing, which easily degrade and react with other components because of their polyhydroxy characteristic. Traditional and advanced technologies have been used to characterize the stability of polyphenols. The main influence factors of stability of polyphenols such as pH, temperature, light, oxygen, enzymes, metal ions, as well as macromolecules, are summarized. Besides, thermal processing greatly promoted the degradation of polyphenols. Thermal degradation mechanisms and products of some polyphenols, such as quercetin and rutin, have been intensively demonstrated. Nevertheless, the structural changes of polyphenols caused by food processing, may lead to different bioactivities from the obtained results based on unprocessed polyphenols. Therefore, to maximize the beneficial effects of polyphenols ingested by human from processed food, the stability of polyphenols in food processing must be thoroughly investigated to assess their real bioactivities. In addition, some available technologies for improving the stability of polyphenols in food processing have been proposed.

Incorporation of polyphenols in baked products

Bakery foods, including breads, cakes, cookies, muffins, rolls, buns, crumpets, pancakes, doughnuts, waffles, and bagels, etc., have been an important diet of humans for thousands of years. As the nutraceuticals with various biological activities, polyphenols, especially polyphenol-enriched products are widely used in bakery foods. The polyphenol-enriched products are mainly from fruits and vegetables, including fruits in whole, juice, puree, jam, and the powder of dried fruits, pomace, and peels. Incorporation of these products not only provide polyphenols, but also supply other nutrients, especially dietary fibers for bakery products. This chapter discussed the thermal stability of different types of polyphenols during baking, and the effect of polyphenols on the sensory attributes of baked foods. Moreover, their role in mitigation of reactive carbonyl species and the subsequent formation of advanced glycation end products, antioxidant and antimicrobial activities have been also discussed. Since polyphenols are subjected to high temperature for dozens of minutes during baking, future works need to focus on the chemical interactions of polyphenols and their oxidized products (quinones) with other food components, and the safety consequence of these interactions.

Ultrasound processing of rutin in food-grade solvents: Derivative compounds, antioxidant activities and optical rotation

The effect of ultrasound was studied on the flavonoid rutin to understand its hydrolysis to aglycones, antioxidant capacity and optical rotation. The total phenolic content increased >56% at 3.6-36 kJ/cm³, indicating production of phenolic compounds. In the water media, at 27 kJ/cm³ and 47 °C, the total flavonoid content increased from control 0.26 ± 0.01 to 0.45 ± 0.02 mg catechin equivalent/mg rutin hydrate. Quercetin yield in citric acid media increased with change in energy density from 0.34 ± 0.09% at 0.1 kJ/cm³ (68 °C) to 2.23 ± 0.04% at 7.0 kJ/cm³ (86 °C). A plummeting effect was only observed in water media after 27 kJ/cm³ by FRAP (47 °C) and DPPH (86 °C) antioxidant activities, indicating that the presence of solutes (citric acid and NaCl) after 27 kJ/cm³ reduced degradation of flavonoids. Furthermore, ultrasonication increased levorotatory rutin enantiomers, that can be used to further modify physico-chemical properties of other food components.

Characterization and Evaluation of the Solubility and Oral Bioavailability of Rutin-Ethanolate Solvate

Rutin has many biological activities, but poor solubility and absorption limit its oral application. This study aimed to investigate the characterization of metastable rutin-ethanolate and its solubility and oral bioavailability. In this research, a soluble rutin/CH₃CH₂OH solvate (Form Π) was prepared by solvent crystallization. High-performance liquid chromatography, gas chromatograph, and ¹H-NMR showed that Form Π was formed by rutin and ethanol in a molar ratio of 1:1. The changes of Fourier transform infrared spectroscopy and ¹H-NMR spectrum and the density functional theory (DFT) calculation predicted hydrogen bond formation between 4'-O of rutin and -OH of ethanol. The results of morphology, solid state CP/MAS ¹³C-NMR, X-ray diffraction, and differential scanning calorimetry (DSC) revealed that Form Π is a novel polymorph that differs from Form Ι (rutin trihydrate). Form Π can be stored for a long time under sealed and dry conditions at 40°C but would gradually transform into Form Ι under humid conditions. Although Form Π is a new metastable polymorph relative to Form Ι, Form Π has better solubility and faster dissolution rate. Moreover, the bioavailability of Form Π was 2.04 times higher than that of Form Ι. This outcome implied that Form Π would be a prospective raw material of oral preparation.

Enzyme-assisted development of biofunctional polyphenol-enriched buckwheat protein: physicochemical properties, in vitro digestibility, and antioxidant activity

BACKGROUND

During the last decade buckwheat was reported to have positive health effects. The present study investigated a high-polyphenol buckwheat protein (Fagopyrum esculentum Moench) prepared by enzyme-assisted processing, together with its physicochemical properties, in vitro digestibility, and antioxidant activity.

RESULTS

Buckwheat protein prepared from the synergistic enzymatic action of α-amylase and amyloglucosidase (E-BWP) had much higher polyphenol content than buckwheat protein prepared by isoelectric precipitation (I-BWP) or salt extraction (S-BWP). Rutin degraded during the process, giving quercetin. The protein constituents and amino acid composition of E-BWP were very similar to those of native buckwheat and were able to meet the WHO/FAO requirements for both children and adults. During in vitro digestion, E-BWP showed anti-digestive behavior with a nitrogen release that was lower than that of I-BWP or S-BWP. The positive effect of the polyphenol content of E-BWP resulted in a higher 1,1-diphenyl-2-picrylhydrazyl (DPPH) content and greater reducing activity.

CONCLUSION

Buckwheat protein with high polyphenol content was successfully developed by enzyme-assisted processing. It had a well-balanced amino acid profile, antidigestive behavior, and high antioxidant activities. The results suggest that enzyme-assisted processing is promising in the production of polyphenol-enriched cereal protein, contributing higher functionality with good nutritional and antioxidant properties. © 2018 Society of Chemical Industry.

Positive and negative effects of polyphenol incorporation in baked foods

Polyphenols are hot research topics worldwide owing to their physiological and pharmaceutical activities. Polyphenols and polyphenol-enriched by-products have been widely used in bakery foods because of their neutraceutical properties. This review summarizes the classification, biosynthesis, main source and analysis of polyphenols and intensively discusses the effects of their incorporation in baked foods. The positive effects of polyphenol incorporation include elevation of antioxidant activity of baked foods, scavenging of food-borne toxins produced during thermal processing and decreasing postprandial serum glucose level. Meanwhile, polyphenol incorporation negatively influences colour, texture and flavour of baked foods and bioavailability of the added polyphenols. Most polyphenols are thermally sensitive and reactive. Thus far, few studies have investigated on neoformed compounds from the reaction of polyphenols or their oxidised products (quinones) with other food components. Before launching polyphenol-incorporated bakery foods in the market, future work should focus on full toxicological evaluation of newly derived compounds from polyphenols.

Simultaneous degradation of β-cypermethrin and 3-phenoxybenzoic acid by Eurotium cristatum ET1, a novel "golden flower fungus" strain isolated from Fu Brick Tea

Beta-cypermethrin (β-CY) and its major metabolite 3-phenoxybenzoic acid (3-PBA) spread extensively in the environment because of utilization in agricultural and home formulations, exerting negative impact on environment as well as human health. Several golden flower fungi were isolated from fu brick tea, by which the biodegradation of β-CY and 3-PBA was evaluated, turning out strain Eurotium cristatum ET1 had the highest capacity. Furthermore, β-CY and 3-PBA degradation rates were positively correlated with biomass of E. cristatum ET1, and the processes of degradation fitted well with a first-order kinetic equation. The half-lives of β-CY and 3-PBA ranged from 3.382 to 11.517 days and 1.749 to 3.194 days, respectively, under different substrate concentrations, incubation temperatures, and pH values. The degraded products were analyzed using gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry, and results showed that E. cristatum ET1 degrades β-CY by transforming it into 3-PBA, which is then gradually metabolized into phenol and catechol. Moreover, E. cristatum ET1 showed efficiency in degrading these metabolites. Our results suggest that this strain is a potential microorganism for bioremediation of pesticide-contaminated environments and fermented foods.

Quercetin as a tyrosinase inhibitor: Inhibitory activity, conformational change and mechanism

Quercetin, a flavonoid compound, was found to inhibit both monophenolase and diphenolase activities of tyrosinase, and its inhibition against diphenolase activity was in a reversible and competitive manner with an IC₅₀ value of (3.08±0.74)×10^-5molL^-1. Quercetin bound to tyrosinase driven by hydrophobic interaction, thereby resulted in a conformational change of tyrosinase and its intrinsic fluorescence quenching. Tyrosinase had one binding site for quercetin with the binding constant in the order of magnitude of 10⁴Lmol^-1. The molecular docking revealed that quercetin bound to the active site of tyrosinase and chelated a copper with the 3', 4'-dihydroxy groups. It can be deduced that the chelation may prevent the entrance of substrate and then inhibit the catalytic activity of tyrosinase. These findings may be helpful to understand the inhibition mechanism of quercetin on tyrosinase and functional research of quercetin in the treatment of pigmentation disorders.