Metabolomic analysis combined with machine learning algorithms enables the evaluation of postharvest pecan color stability.

Nut kernel color is a crucial quality indicator affecting the consumers first impression of the product. While growing evidence suggests that plant phenolics and their derivatives are linked to nut kernel color, the compounds (biomarkers) responsible for kernel color stability during storage remain elusive. Here, pathway-based metabolomics with machine learning algorithms were employed to identify key metabolites of postharvest pecan color stability. Metabolites in phenylpropanoid, flavonoid, and anthocyanin biosynthetic pathways were analyzed in the testa of nine pecan cultivars using liquid chromatography-mass spectrometry. With color measurements, different machine learning models were compared to find relevant biomarkers of pecan color phenotypes. Results revealed potential marker compounds that included flavonoid precursors and anthocyanidins as well as anthocyanins (e.g., peonidin, delphinidin-3-O-glucoside). Our findings provide a foundation for future research in the area, and will help select genes/proteins for the breeding of pecans with stable and desirable kernel color.

A new UiO-66-NH2 MOF-based nano-immobilized DFR enzyme as a biocatalyst for the synthesis of anthocyanidins.

Anthocyanidins and anthocyanins are one subclass of flavonoids in plants with diverse biological functions and have health-promoting effects. Dihydroflavonol 4-reductase (DFR) is one of the important enzymes involved in the biosynthesis of anthocyanidins and other flavonoids. Here, a new MOF-based nano-immobilized DFR enzyme acting as a nano-biocatalyst for the production of anthocyanidins in vitro was designed. We prepared UiO-66-NH2 MOF nano-carrier and recombinant DFR enzyme from genetic engineering. DFR@UiO-66-NH2 nano-immobilized enzyme was constructed based on covalent bonding under the optimum immobilization conditions of the enzyme/carrier ratio of 250 mg/g, 37 °C, pH 6.5 and fixation time of 10 min. DFR@UiO-66-NH2 was characterized and its catalytic function for the synthesis of anthocyanidins in vitro was testified using UPLC-QQQ-MS analysis. Compared with free DFR enzyme, the enzymatic reaction catalyzed by DFR@UiO-66-NH2 was more easily for manipulation in a wide range of reaction temperatures and pH values. DFR@UiO-66-NH2 had better thermal stability, enhanced adaptability, longer-term storage, outstanding tolerances to the influences of several organic reagents and Zn2+, Cu2+ and Fe2+ ions, and relatively good reusability. This work developed a new MOF-based nano-immobilized biocatalyst that had a good prospect of application in the green synthesis of anthocyanins in the future.

Dietary Anthocyanins Mitigate High-Fat Diet-Induced Hippocampal Inflammation in Mice.

BACKGROUND: Obesity and consumption of high-fat diets (HFD) are associated with intestinal permeabilization and increased paracellular transport of endotoxins, which can promote neuroinflammation. Inflammation can affect the hypothalamic pituitary adrenal (HPA) axis, which controls responses to stress and downregulates the brain-derived neurotrophic factor (BDNF), which can promote anxiety and depression, conditions frequently found in obesity. We previously showed that consumption of anthocyanins (AC) mitigate HFD-induced insulin resistance, intestinal permeability, and inflammation. OBJECTIVES: This study investigated if a dietary supplementation with a cyanidin- and delphinidin-rich extract (CDRE) could counteract HFD/obesity-induced hippocampal inflammation in mice. METHODS: C57BL/6J male mice were fed for 14 wk on one of the following diets: 1) a control diet containing 10% total calories from fat (C), 2) a control diet supplemented with 40 mg AC/kg body weight (BW) (CAC), 3) a HFD containing 60% total calories from fat (lard) (HF), or 4) the HFD supplemented with 2, 20, or 40 mg AC/kg BW (HFA2, HFA20, and HFA40, respectively). In plasma and in the hippocampus, parameters of neuroinflammation and the underlying cause (endotoxemia) and consequences (alterations to the HPA and BDNF downregulation) were measured. RESULTS: Consumption of the HFD caused endotoxemia. Accordingly, hippocampal Tlr4 mRNA levels were 110% higher in the HF group, which were both prevented by CDRE supplementation. Consumption of the HFD also caused: 1) microgliosis and increased expression of genes involved in neuroinflammation, that is, Iba-1, Nox4, Tnfα, and Il-1ß, 2) alterations of HPA axis regulation, that is, with low expression of mineralocorticoid (MR) and glucocorticoid (GR) receptors; and 3) decreased Bdnf expression. Supplementation of HFD-fed mice with CDRE mitigated neuroinflammation, microgliosis, and MR and BDNF decreases. CONCLUSIONS: CDRE supplementation mitigates the negative effects associated with HFD consumption and obesity in mouse hippocampus, in part by decreasing inflammation, improving glucocorticoid metabolism, and upregulating BDNF.

Structural and Interactional Analysis of the Flavonoid Pathway Proteins: Chalcone Synthase, Chalcone Isomerase and Chalcone Isomerase-like Protein.

Chalcone synthase (CHS) and chalcone isomerase (CHI) catalyze the first two committed steps of the flavonoid pathway that plays a pivotal role in the growth and reproduction of land plants, including UV protection, pigmentation, symbiotic nitrogen fixation, and pathogen resistance. Based on the obtained X-ray crystal structures of CHS, CHI, and chalcone isomerase-like protein (CHIL) from the same monocotyledon, Panicum virgatum, along with the results of the steady-state kinetics, spectroscopic/thermodynamic analyses, intermolecular interactions, and their effect on each catalytic step are proposed. In addition, PvCHI's unique activity for both naringenin chalcone and isoliquiritigenin was analyzed, and the observed hierarchical activity for those type-I and -II substrates was explained with the intrinsic characteristics of the enzyme and two substrates. The structure of PvCHS complexed with naringenin supports uncompetitive inhibition. PvCHS displays intrinsic catalytic promiscuity, evident from the formation of p-coumaroyltriacetic acid lactone (CTAL) in addition to naringenin chalcone. In the presence of PvCHIL, conversion of p-coumaroyl-CoA to naringenin through PvCHS and PvCHI displayed ~400-fold increased Vmax with reduced formation of CTAL by 70%. Supporting this model, molecular docking, ITC (Isothermal Titration Calorimetry), and FRET (Fluorescence Resonance Energy Transfer) indicated that both PvCHI and PvCHIL interact with PvCHS in a non-competitive manner, indicating the plausible allosteric effect of naringenin on CHS. Significantly, the presence of naringenin increased the affinity between PvCHS and PvCHIL, whereas naringenin chalcone decreased the affinity, indicating a plausible feedback mechanism to minimize spontaneous incorrect stereoisomers. These are the first findings from a three-body system from the same species, indicating the importance of the macromolecular assembly of CHS-CHI-CHIL in determining the amount and type of flavonoids produced in plant cells.

Polyphenolic compounds in the combat of foodborne infections - An update on recent evidence.

In recent years, the incidence of food-borne bacterial enteric diseases has increased worldwide causing significant health care and socioeconomic burdens. According to the World Health Organization, there are an estimated 600 million cases of foodborne illnesses worldwide each year, resulting in 420,000 deaths. Despite intensive efforts to tackle this problem, foodborne pathogenic microorganisms continue to be spread further. Therefore, there is an urgent need to find novel anti-microbial non-toxic compounds for food preservation. One way to tackle this issue may be the usage of polyphenols, which have received increasing attention in the recent years given their pleotropic health-promoting properties. This prompted us to perform a literature search summarizing studies from the past 10 years regarding the potential anti-microbial and disease-alleviating effects of plant-derived phenolic compounds against foodborne bacterial pathogens. The included 16 studies provide evidence that polyphenols show pronounced anti-bacterial and anti-oxidant effects against both Gram-positive and Gram-negative bacterial species. In addition, synergistic anti-microbial effects in combination with synthetic antibiotics were observed. In conclusion, phenolic compounds may be useful as natural anti-microbial agents in the food, agricultural, and pharmaceutical industries in the combat of foodborne infections.

The relationship of dietary flavonoids and periodontitis in US population: a cross-sectional NHANES analysis.

OBJECTIVES: We investigated the association between dietary flavonoids intake and periodontitis. MATERIALS AND METHODS: This cross-sectional study analyzed data from the US National Health and Nutrition Examination Survey 2009-2010 on 3025 participants aged between 30 and 80 years who had full-mouth periodontal examination and dietary flavonoids intake data. This study used periodontal pocket depth (PPD) and clinical attachment loss (CAL) as periodontitis markers. Data were analyzed using multivariate linear regression. RESULTS: After adjusting confounders, the middle tertile of total dietary flavonoids was associated with decreased mean PPD (0.06 mm, P = 0.016) and mean CAL (0.13 mm, P = 0.001) and the top tertile of total dietary flavonoids was significantly associated with decreases in mean PPD (0.05 mm, P = 0.029) and mean CAL (0.11 mm, P = 0.010). Both the middle and top tertiles of total flavonoids intake were significantly related with decreased mean CAL in females, those flossing 0 days/week, overweight and non-diabetic population but not in males, smokers, those flossing 1-6 days/week and diabetic population. Higher anthocyanidins, flavones and flavonols intake was significantly associated with decreased mean PPD and mean CAL while higher flavanones intake was only significantly associated with decreased mean CAL. Higher anthocyanidins intake was particularly related with greatest decreases in mean CAL (top tertile: 0.22 mm, middle tertile: 0.17 mm, both P < 0.010). However, no significant associations were found between isoflavones and flavan_3_ols intake and mean CAL. CONCLUSIONS: Higher dietary flavonoids intake may be beneficial for periodontal health. CLINICAL RELEVANCE: Additional anthocyanidins, flavanones, flavones and flavonols intake was associated with improved periodontal health.

Effects of anthocyanidins on the conformational transition of Aß(1-42) peptide: Insights from molecular docking and molecular dynamics simulations.

Recent evidence from in vitro and in vivo studies has shown that anthocyanins and anthocyanidins can reduce and inhibit the amyloid beta (Aß) species, one of the hallmarks of Alzheimer's disease (AD). However, their inhibition mechanisms on Aß species at molecular details remain elusive. Therefore, in the present study, molecular modelling methods were employed to investigate their inhibitory mechanisms on Aß(1-42) peptide. The results highlighted that anthocyanidins effectively inhibited the conformational transitions of helices into beta-sheet (ß-sheet) conformation within Aß(1-42) peptide by two different mechanisms: 1) the obstruction of two terminals from coming into contact due to the binding of anthocyanidins with residues of N- and second hydrophobic core (SHC)-C-terminals, and 2) the prevention of the folding process due to the binding of anthocyanidin with the central polar (Asp23 and Lys28) and native helix (Asp23, Lys28, and Leu34) residues. These new findings on the inhibition of ß-sheet formation by targeting both N- and SHC-C-terminals, and the long-established target, D23-K28 salt bridge residues, not with the conventional central hydrophobic core (CHC) as reported in the literature, might aid in designing more potent inhibitors for AD treatment.

Association of dietary flavonoid intakes with prevalence of chronic respiratory diseases in adults.

BACKGROUND AND AIMS: Flavonoids are a class of secondary plant metabolites that have been shown to have multiple health benefits, including antioxidant and anti-inflammatory. This study was to explore the association between dietary flavonoid consumption and the prevalence of chronic respiratory diseases (CRDs) in adults. METHODS AND RESULTS: The six main types of flavonoids, including isoflavones, anthocyanidins, flavan-3-ols, flavanones, flavones, and flavonols, were obtained from the National Health and Nutrition Examination Survey (NHANES) 2007-2010 and 2017-2018 by the two 24-h recall interviews. The prevalence of CRDs, including asthma, emphysema, and chronic bronchitis, was determined through a self-administered questionnaire. The analysis included 15,753 participants aged 18 years or older who had completed a diet history interview. After adjustment for potential confounders, the inverse link was found with total flavonoids, anthocyanidins, flavanones, and flavones, with an OR (95%CI) of 0.86 (0.75-0.98), 0.84 (0.72-0.97), 0.80(0.69-0.92), and 0.85(0.73-0.98) for the highest group compared to the lowest group. WQS regression revealed that the mixture of flavonoids was negatively linked with the prevalence of CRDs (OR = 0.88 [0.82-0.95], P < 0.01), and the largest effect was mainly from flavanones (weight = 0.41). In addition, we found that flavonoid intake was negatively linked with inflammatory markers, and systemic inflammation significantly mediated the associations of flavonoids with CRDs, with a mediation rate of 12.64% for CRP (P < 0.01). CONCLUSION: Higher flavonoid intake was related with a lower prevalence of CRDs in adults, and this relationship may be mediated through systemic inflammation.

Five similar anthocyanidin molecules display distinct disruptive effects and mechanisms of action on Aß1-42 protofibril: A molecular dynamic simulation study.

Alzheimer's disease (AD) is associated with the deposition of amyloid-ß (Aß) fibrillary aggregates. Disaggregation of Aß fibrils is considered as one of the promising AD treatments. Recent experimental studies showed that anthocyanidins, one type of flavonoids abundant in fruits/vegetables, can disaggregate Aß fibrillary aggregates. However, their relative disruptive capacities and underlying mechanisms are largely unknown. Herein, we investigated the detailed interactions between five most common anthocyanidins (cyanidin, aurantinidin, peonidin, delphinidin, and pelargonidin) and Aß protofibril (an intermediate of Aß fibrillization) by performing microsecond molecular dynamic simulations. We found that all five anthocyanidins can destroy F4-L34-V36 hydrophobic core and K28-A42 salt bridge, leading to Aß protofibril destabilization. Aurantinidin exhibits the strongest damage to Aß protofibril (with the most severe disruption on K28-A42 salt bridges), followed by cyanidin (with the most destructive effect on F4-L34-V36 core). Detailed analyses reveal that the protofibril-destruction capacities of anthocyanidins are subtly modulated by the interplay of anthocyanidin-protofibril hydrogen bonding, hydrophobic, aromatic stacking interactions, which are dictated by the number or location of hydroxyl/methyl groups of anthocyanidins. These findings provide important mechanistic insights into Aß protofibril disaggregation by anthocyanidins, and suggest that aurantinidin/cyanidin may serve as promising starting-points for the development of new drug candidates against AD.

Heavy metal levels and flavonoid intakes are associated with chronic obstructive pulmonary disease: an NHANES analysis (2007-2010 to 2017-2018).

BACKGROUND: The association between exposure to environmental metals and chronic obstructive pulmonary disease (COPD) is preventing chronic lung diseases. However, little is currently known about the interaction between heavy metals and flavonoids in relation to the risk of COPD. This study aims to bridge this knowledge gap by leveraging The National Health and Nutrition Examination Survey (NHANES) database to evaluate thecorrelation between blood levels of heavy metals (cadmium, lead, mercury) and the intake of various flavonoid compounds (isoflavones, anthocyanidins, flavan-3-ols, flavanones, flavones, flavonols, total flavonoids). Additionally, appropriate dietary recommendations are provided based on the study findings. MATERIALS AND METHODS: Cross-sectional analysis was conducted using the 2007-2010 and 2017-2018 NHANES data. Specialized weighted complex survey design analysis software was used for data analysis. Multivariate logistic regression models and restricted cubic splines (RCS) were used to evaluate the relationship between blood heavy metal levels, flavonoids intake, and COPD incidence in all participants, and to explore the effect of different levels of flavonoids intake on COPD caused by heavy metal exposure. RESULTS: A total of 7,265 adults aged ≥ 40 years were analyzed. Higher levels of blood cadmium (Cd), blood lead and Anthocyanidin (AC) intake were independently associated with an increased risk of COPD (Cd highest quantile vs. lowest: OR = 1.73, 95% CI, 1.25-2.3; Lead highest quantile vs. lowest quantile: OR = 1.44, 95% CI, 1.11-1.86; AC highest quantile vs. lowest: OR = 0.73, 95% CI, 0.54-0.99). When AC intake exceeded 11.56 mg/d, the effect of Cd exposure on COPD incidence decreased by 27%, and this finding was more significant in smokers. CONCLUSION: Higher levels of Cd (≥ 0.45ug/L) and lead (≥ 0.172 ug/L) were positively correlated with the risk of COPD among participants aged 40 years and above, while AC intake (≥ 11.56 mg/d) could reduce the risk related to blood Cd.

Whole-genome resequencing and transcriptome analyses of four generation mutants to reveal spur-type and skin-color related genes in apple (Malus domestica Borkh. Cv. Red delicious).

BACKGROUND: Bud sport is a kind of somatic mutation that usually occurred in apple. 'Red Delicious' is considered to be a special plant material of bud sport, whereas the genetic basis of plant mutants is still unknown. In this study, we used whole-genome resequencing and transcriptome sequencing to identify genes related to spur-type and skin-color in the 'Red Delicious' (G0) and its four generation mutants including 'Starking Red' (G1), 'Starkrimson' (G2), 'Campbell Redchief' (G3) and 'Vallee Spur' (G4). RESULTS: The number of single nucleotide polymorphisms (SNPs), insertions and deletions (InDels) and structural variations (SVs) were decreased in four generation mutants compared to G0, and the number of unique SNPs and InDels were over 9-fold and 4-fold higher in G1 versus (vs.) G2 and G2 vs. G3, respectively. Chromosomes 2, 5, 11 and 15 carried the most SNPs, InDels and SVs, while chromosomes 1 and 6 carried the least. Meanwhile, we identified 4,356 variation genes by whole-genome resequencing and transcriptome, and obtained 13 and 16 differentially expressed genes (DEGs) related to spur-type and skin-color by gene expression levels. Among them, DELLA and 4CL7 were the potential genes that regulate the difference of spur-type and skin-color characters, respectively. CONCLUSIONS: Our study identified potential genes associated with spur-type and skin-color differences in 'Red Delicious' and its four generation mutants, which provides a theoretical foundation for the mechanism of the apple bud sport.

Relationship between Chemical Structure and Biological Activity Evaluated In Vitro for Six Anthocyanidins Most Commonly Occurring in Edible Plants.

Numerous studies have provided evidence that diets rich in anthocyanins show a broad spectrum of health benefits. Anthocyanins in nature are usually found in the form of glycosides. Their aglycone forms are called anthocyanidins. The chemical structure of anthocyanins is based on the flavylium cation, but they differ in the position and number of substituents. However, the bioactives and foods that contain them are frequently treated as a uniform group of compounds exhibiting the same biological activity, without paying attention to the structural differences between individual anthocyanidins. The aim of this study was to find out how structural differences impact the biological activity of the six most common dietary anthocyanidins, i.e., delphinidin (Dp), petunidin (Pt), cyanidin (Cd), malvidin (Mv), pelargonidin (Pg) and peonidin (Po). The study concentrated on redox-related phenomena and compared the following parameters: antioxidant activity (measured using various methods: spectrophotometric tests (ABTS, DPPH), ORAC assay and CAA test (cellular antioxidant activity)), the ability to inhibit growth of human colon cancer cells (HT29; determined using MTT assay), and the ability of studied compounds to protect DNA from oxidative damage (comet assay). Based on the obtained results, the relationship between the structure of studied anthocyanidins and their biological activity was assessed. The obtained results revealed that the number and position of the hydroxyl and methoxy groups in the anthocyanidin structure strongly influenced not only the color of anthocyanidins but most of all their antioxidant and biological activities.

Exploring the potentials of sorghum genotypes: a comprehensive study on nutritional qualities, functional metabolites, and antioxidant capacities.

Introduction: Sorghum, long regarded as one of the most underutilized crops, has received attention in recent years. As a result, conducting multidisciplinary studies on the potential and health benefits of sorghum resources is vital if they are to be fully exploited. In this study, the nutritional contents, functional metabolites, and antioxidant capacities of 23 sorghum breeding lines and three popular cultivars were assessed. Materials and method: All of the sorghum genotypes were grown under the same conditions, and mature seeds were hand-harvested. The metabolite contents and antioxidant capacities of sorghum seeds were assessed using standard protocols. Fatty acids were quantified using a gas chromatography-flame ionization detector, whereas flavonoids and 3-deoxyanthocyanidins were analyzed using a liquid chromatography-tandem mass spectrometry method. The data were analyzed using both univariate and multivariate statistical approaches. Results and discussion: Total protein (9.05-14.61%), total fat (2.99-6.91%), crude fiber (0.71-2.62%), dietary fiber (6.72-16.27%), total phenolic (0.92-10.38 mg GAE/g), and total tannin (0.68-434.22 mg CE/g) contents varied significantly across the sorghum genotypes (p < 0.05). Antioxidant capacity, measured using three assays, also differed significantly. Five fatty acids, including palmitic, stearic, oleic, linoleic, and linolenic acids, were found in all the sorghum genotypes with statistically different contents (p < 0.05). Furthermore, the majority of the sorghum genotypes contained four 3-deoxyanthocyanidins, including luteolinidin, apigeninidin, 5-methoxyluteolinidin, and 7-methoxyapigeninidin, as well as two dominant flavonoids, luteolin and apigenin. Compared to the cultivars, some breeding lines had significantly high levels of metabolites and antioxidant activities. On the other hand, statistical analysis showed that total tannin, total phenolic, and antioxidant capacities varied significantly across white, yellow, and orange genotypes. Principal component analysis was used to differentiate the sorghum genotypes based on seed color and antioxidant index levels. Pearson's correlation analysis revealed strong links between biosynthetically related metabolites and those with synergistic antioxidant properties. Conclusion: This research demonstrated the diversity of the sorghum resources investigated. Those genotypes with high levels of nutritional components, functional metabolites, and antioxidant activities could be used for consumption and breeding programs.

Association between dietary anthocyanidins intake and depression among US adults: a cross-sectional study (NHANES, 2007-2010 and 2017-2018).

BACKGROUND: Anthocyanidins encompass a diverse array of compounds that possess notable anti-inflammatory and antioxidant properties with pharmacological activity. However, the correlation between the consumption of anthocyanidins through diet and its impact on depression has yet to be investigated. METHODS: This study utilized the Food and Nutrient Database for Dietary Studies (FNDDS) expanded flavonoid intake database, as well as data from the National Health and Nutrition Examination Survey (NHANES) from the years 2007 to 2010 and 2017 to 2018. The analysis of the collected data was conducted in R, following the guidelines outlined in the official NHANES user guide "Stratified Multi-stage Probability Sampling". Three different models were developed using logistic regression to assess the protective effects of T3 (representing the highest intake of anthocyanidins) against depression. Additionally, the study aimed to investigate whether there existed a non-linear relationship between the dietary intake of anthocyanidins and the prevalence of depression by employing restricted cubic spline (RCS) analysis. RESULTS: A total of 6,845 eligible participants were included in this cross-sectional study, with their data appropriately weighted to represent a population of 89.8 million people in the United States of America. The results demonstrated that individuals diagnosed with depression had a significantly lower dietary intake of anthocyanidins compared to those without depression (P < 0.0001). Moreover, significant differences were observed among different participant groups regarding socioeconomic status and the presence of chronic physical illnesses (such as hypertension, glucose status, and chronic kidney disease risk, etc.) (P < 0.05). After adjustment for covariates, participants with the highest intake of anthocyanins (T3) demonstrated a significantly reduced risk of depression [ORT3 = 0.67, 95%CI: (0.48-0.95), (Ptrend= 0.02]. Furthermore, the RCS analysis revealed a significant linear relationship between dietary anthocyanidin intake and depression (P for non-linear = 0.5876). CONCLUSION: Our findings reveal a negative association between dietary anthocyanidin intake and depression.

The association between dietary intake of flavonoids and its subclasses and the risk of metabolic syndrome.

Background: The healthiest way to prevent metabolic syndrome (MetS) is through behavioral and nutritional adjustments. We examined the relationship between total flavonoids intake, flavonoid subclasses, and clinically manifest MetS. Methods: A cross-sectional analysis was conducted among 28,719 individuals from the National Health and Nutrition Examination Survey (NHANES) and Food and Nutrient Database for Dietary Studies (FNDDS) 2007-2011 and 2017-2018. Two 24-h reviews were conducted to determine flavonoids intake and subclasses. The link between flavonoids intake and MetS was investigated using a multivariate logistic regression model. Results: Q2 and Q3 of total flavonoids intake were associated with 20 and 19% lower risk of incident MetS after adjusting age and sex. Anthocyanidins and flavanones intake in Q2 and Q3 substantially reduced the MetS risk compared to Q1. MetS risk decreased steadily as the total intake of flavonoids increased to 237.67 mg/d. Flavanones and anthocyanidins also displayed V-shaped relationship curves (34.37 and 23.13 mg/d). Conclusion: MetS was adversely linked with total flavonoids intake, flavanones, and anthocyanidins. Moreover, the most effective doses of total flavonoids, flavanones, and anthocyanidins were 237.67, 34.37, and 23.13 mg/d, respectively, potentially preventing MetS.

Coordinated encapsulation by ß-cyclodextrin and chitosan derivatives improves the stability of anthocyanins.

To improve the stability of anthocyanins (ACNs), ACNs were loaded into dual-encapsulated nanocomposite particles by self-assembly using ß-cyclodextrin (ß-CD) and two different water-soluble chitosan derivatives, namely, chitosan hydrochloride (CHC) and carboxymethyl chitosan (CMC). The ACN-loaded ß-CD-CHC/CMC nanocomplexes with small diameters (333.86 nm) and had a desirable zeta potential (+45.97 mV). Transmission electron microscopy (TEM) showed that the ACN-loaded ß-CD-CHC/CMC nanocomplexes had a spherical structure. Fourier-transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (1H NMR) and X-ray diffraction (XRD) confirmed that the ACNs in the dual nanocomplexes were encapsulated in the cavity of the ß-CD and that the CHC/CMC covered the outer layer of ß-CD through noncovalent hydrogen bonding. The ACNs from the dual-encapsulated nanocomplexes improved stability of ACNs under adverse environmental conditions or in a simulated gastrointestinal environment. Further, the nanocomplexes exhibited good storage stability and thermal stability over a wide pH range when added into simulated electrolyte drinks (pH = 3.5) and milk tea (pH = 6.8). This study provides a new option for the preparation of stable ACNs nanocomplexes and expands the applications for ACNs in functional foods.

Extraction Solvents Affect Anthocyanin Yield, Color, and Profile of Strawberries.

Anthocyanins are a major group of plant pigments that have antioxidant activities. Pigments play a major role in human health and have attracted a lot of attention globally. Many factors affect anthocyanin yields, such as solvent type, incubation time, solvent-to-sample ratio, sample type, and temperature. The first parameter was tested, and the rest were considered constant in this experiment. A total of nine organic and water-based solvents (methanol and chloroform: methanol, acetone, ethanol, water) and their combinations were compared to extract anthocyanins from freshly-pureed strawberries. Solvents changed anthocyanin yield, color parameters, and profile. The color parameters of a* values lower than 30, L* values higher than 85, hue angle more than 40, and chroma less than 30 indicated some color degradation in strawberry anthocyanins. Therefore, the best solvents for anthocyanin assessment were methanol and methanol: water. The second-best solvent was the pH differential buffers. Other solvents such as ethanol, chloroform: methanol, water, and water-based solvents extracted considerable amounts of anthocyanins; however, they showed some degree of color degradation, evidenced by the color parameters. Acetone did not yield a stable extract which degraded over 48 h of storage at 4 °C. The extraction solvent determined the main anthocyanin of the anthocyanins profile. Pelargonidin was the major anthocyanin in chloroform: methanol solvent, while delphinidin was dominant in all other solvents.

Prediction of Anthocyanidins Content in Purple Chinese Cabbage Based on Visible/Near Infrared Spectroscopy.

Purple Chinese cabbage (PCC) has become a new breeding trend due to its attractive color and high nutritional quality since it contains abundant anthocyanidins. With the aim of rapid evaluation of PCC anthocyanidins contents and screening of breeding materials, a fast quantitative detection method for anthocyanidins in PCC was established using Near Infrared Spectroscopy (NIR). The PCC samples were scanned by NIR, and the spectral data combined with the chemometric results of anthocyanidins contents obtained by high-performance liquid chromatography were processed to establish the prediction models. The content of cyanidin varied from 93.5 mg/kg to 12,802.4 mg/kg in PCC, while the other anthocyanidins were much lower. The developed NIR prediction models on the basis of partial least square regression with the preprocessing of no-scattering mode and the first-order derivative showed the best prediction performance: for cyanidin, the external correlation coefficient (RSQ) and standard error of cross-validation (SECV) of the calibration set were 0.965 and 693.004, respectively; for total anthocyanidins, the RSQ and SECV of the calibration set were 0.966 and 685.994, respectively. The established models were effective, and this NIR method, with the advantages of timesaving and convenience, could be applied in purple vegetable breeding practice.

Identification and characterisation of MdUGT78T2 as a galactosyltransferase with dual activity on flavonol and anthocyanidin substrates in red-skinned apple fruit (Malus domestica L.).

Anthocyanidin and flavonol glycosides have been linked to the health-promoting effects associated with apple consumption. However, very few enzymes involved in flavonoid glycosylation have been characterised to date. Here, we present the identification and phylogenetic analysis of 234 putative glycosyltransferases involved in flavonoid biosynthesis, and detail the biochemical and structural characterisation of MdUGT78T2 as a strict galactosyltransferase involved in the formation of quercetin-3-O-galactoside and cyanidin-3-O-galactoside, the major glycoconjugates of flavonoids in apple. The enzyme is also active on other flavonoids but with a lower catalytic efficiency. Our data, complemented with gene expression analysis suggest that MdUGT78T2 synthesises the glycoconjugates at both the early and late stages of fruit development. This newly discovered type of catalytic activity can potentially be exploited for in vitro modification of flavonoids to increase their stability in food products and to modify apple fruits and other commercial crops through breeding approaches to enhance their health benefits.

Research progress of proanthocyanidins and anthocyanidins.

Proanthocyanidins (PA) are polyphenol compounds that are widely distributed in the bark, fruit core, skin, or seeds of various plants. Anthocyanidins are water-soluble natural pigments widely found in plants. They are all flavonoids, a major coloring substance in plants and fruits. In recent years, research into PA and anthocyanins has become increasingly popular because of their excellent anti-oxidation, scavenging of reactive oxygen free radicals and other physical and chemical activities, and their anti-cancer, vision protection, aging prevention, skin beauty pharmacological, and nutraceutical effects. Especially, recent systematic reviews and meta-analyses indicate their value, safety, and efficacy in the prevention, adjuvant therapy, and management of cardiometabolic disease. Here, we summarize their research progress from the aspects of chemical structure, biosynthetic pathways, distribution, extraction and separation, coloration, efficacy, and potential. The comparison between them might provide a reference for their development and efficient utilization. However, more large-sample-size randomized controlled trials and high-quality studies are needed to firmly establish their clinical efficacy.