Peonidin-3-glucoside Research Articles

Biomarkers of the main nutritional components in purple rice during five successive grain filling stages

Differences in main nutritional components in relation to biomarkers of metabolites in purple rice grains at different fillings stages have not been determined previously. This study measured the contents of amino acids, several nutritional indicators, and mineral elements in purple rice grains at five stages following the filling stage. The results revealed that the amino acid, ascorbic acid, total sugar, carotenoid, vitamin B9, cyanidin-3-O-glucoside, peonidin 3-glucoside and seven minerals were highest in the final stage of grain filling. Citric acid, L-isoleucine, trigonelline, and L-glutamate are key metabolites in the metabolic pathway and exhibit strong correlations with various nutritional indicators. Hence, this research preliminarily suggested that trigonelline, L-isoleucine, L-glutamate, and citric acid could be potential biomarkers of nutritional components in purple rice grains during various postfilling stages.

Role of superfine grinding in purple-whole-wheat flour. Part Ⅰ: Impacts of size reduction on anthocyanin profile, physicochemical and antioxidant properties

While purple wheat has garnered attention for its rich and complex anthocyanin profile, its coarse bran may pose challenges for its further utilization in bakery products. Superfine grinding is a promising size-reduction technique to enhance the practicability of purple-whole-wheat flour (PWWF) as a functional food ingredient. In this study, purple wheat was ground into flours of three different particle sizes (Q50 = 214.8 μm, 55.6 μm and 31.3 μm, respectively), followed by characterising their micro-morphology, physicochemical and antioxidant capacity properties, as well as identifying and quantifying anthocyanin compositions. Three antioxidant capacity assays - TPC, ABTS and ORAC - suggest that superfine PWWF exhibited an antioxidant capacity up to 1.6 times greater than that of original PWWF. Triple quadrupole mass spectrometric results indicate that the content of individual anthocyanin compounds increased with size reduction. The anthocyanin profile of purple wheat was complex, comprising 26 species of which 12 were acylated. Among them, cyanidin 3-glucoside, peonidin 3-glucoside, malvidin 3-glucoside, delphinidin 3-glucoside and malvidin 3-rutinoside accounted for over 80% of the total content. Altogether, these results highlight the unique functionality of superfine ground PWWF and lay the groundwork for further utilization into bakery products with enhanced health benefits.

High-Performance Liquid Chromatography–Quadrupole Time-of-Flight Tandem Mass Spectrometry-Based Profiling Reveals Anthocyanin Profile Alterations in Berries of Hybrid Muscadine Variety FLH 13-11 in Two Continuous Cropping Seasons

FLH 13-11 is an F1 interspecific hybrid muscadine grape genotype that was developed to produce new anthocyanins for pigment color stability. This hybrid resulted from a cross between ‘Marsh’ (Vitis munsoniana) and ‘Magoon’ (V. rotundifolia) and has been cultivated for the wine and juice industry. This report characterizes anthocyanins produced in fully ripe berries and reveals a significant difference in total anthocyanin contents from two continuous cropping seasons. High-performance liquid chromatography with a diode array detector (HPLC-DAD) and HPLC–quadrupole time-of-flight tandem mass spectrometry (HPLC-qTOF-MS/MS) were used to profile anthocyanins in berries. The resulting data showed that fourteen anthocyanins were detected, six from 2011 and nine from 2012, with only one produced in both seasons. However, the anthocyanidin profiles of the berries were the same. Five anthocyanins were annotated as diglucosides of anthocyanidins based on MS/MS features, including delphinidin 3,5-diglucoside produced in both seasons, cyanidin 3,5-diglucoside mainly formed in 2011, petunidin 3,5-diglucoside, malvidin 3,5-diglucoside, and peonidin 3,5-glucoside only detected in 2012. Also, three anthocyanidin-diglucoside-like anthocyanins and three monoglucosides, including peonidin 3-glucoside, delphinidin 3-glucoside like, and pelargonidin 3-glucoside-like anthocyanins, were detected in 2011 and 2012, respectively. These results indicate that FLH 13-11 can produce both anthocyanidin-diglucosides and -monoglucosides, and their biosynthesis is closely dependent on cropping years.

Accumulation patterns of anthocyanin and γ-oryzanol during black rice grain development.

Pigmented rice, especially black rice, is gaining popularity as it is rich in antioxidants such as anthocyanins and γ-oryzanol. At present, knowledge about temporal control of biosynthesis and accumulation of antioxidants during grain development is limited. To address this, the accumulation patterns of anthocyanins and γ-oryzanol were assessed in two distinct black rice genotypes over the course of grain development, and the expression of known regulatory genes for anthocyanin biosynthesis was examined. The results indicated that total γ-oryzanol content increased continuously throughout grain development, while total anthocyanins peaked at dough stage (15 to 21 days after flowering) followed by a decline until grain maturity in both genotypes. However, the rate of decrease in anthocyanin content differed between genotypes, and a more prominent decline in cyanidin 3-O-glucoside (C3G) relative to peonidin 3-O-glucoside (P3G) was observed for both. Anthocyanin content was closely linked with the expression of key regulatory genes in the MBW (MYB-bHLH-WD40) complex. This improved knowledge of the genotype-specific biosynthesis (anthocyanins only) and accumulation patterns of anthocyanins and γ-oryzanol can inform subsequent research efforts to increase concentrations of these key antioxidants in black rice grains.

Anthocyanins degradation mediated by β-glycosidase contributes to the color loss during alcoholic fermentation in a structure-dependent manner

Anthocyanins deteriorate during fermentation to varying degrees depending on the structure of the anthocyanin, thus affecting the sensory quality of the wine, and the degradation of anthocyanins is closely associated with the β-glycosidase. In this study, the alcoholic fermentation systems containing cyanidin-3-O-glucoside (C3G), peonidin-3-O-glucoside (Pn3G), delphinidin-3-O-glucoside (D3G), petunidin-3-O-glucoside (Pt3G), and malvidin-3-O-glucoside (M3G) incubated for eight days. Our results indicated that the color of the systems containing different anthocyanins saw significant and dissimilar changes during fermentation, in relation to anthocyanin degradation. The five anthocyanins showed varying degradation degrees, which are relevant to theβ-glycosidase produced by yeast. Enzyme kinetics and molecular docking analysis showed the affinity between anthocyanins and β-glucosidase: C3G < M3G < Pn3G < Pt3G < D3G. This study demonstrated that β-glycosidase had distinct effects on anthocyanins with diverse structures, resulting in different color changes in fermentation systems. It provided a potential strategy for sensory quality improvement during the fermentation of fruit wines rich in anthocyanins.

OsGSTU34, a Bz2-like anthocyanin-related glutathione transferase transporter, is essential for rice (Oryza sativa L.) organs coloration

Anthocyanins are a flavonoid compound known as one of the most important chromogenic substances. They play several functions, including health promotion and sustaining plants during adverse conditions. They are synthesized at the endoplasmic reticulum and sequestered in the vacuole. In this work, we generated knock-out lines of OsGSTU34, a glutathione transporter's tau gene family, with no transgene line and off-target through CRISPR/Cas9 mutagenesis and highlighted the loss of pigmentation in rice flowers, leaves, stems, shoots, and caryopsis. The anthocyanin quantification in the wild-type BLWT and mutant line BLG34-8 caryopsis showed that cyanidin-3-O-glucoside (C3G) and peonidin-3-O-glucoside (P3G) were almost undetectable in the mutant line. A tandem mass tag (TMT) labeling proteomic analysis was conducted to elucidate the proteomic changes in the BLWT and BLG34-8. The result revealed that 1175 proteins were altered, including 408 that were down-regulated and 767 that were upregulated. The accumulation of the OsGSTU34-related protein (Q8L576), along with several anthocyanin-related proteins, was down-regulated. The enrichment analysis showed that the down-regulated proteins were enriched in different pathways, among which the phenylpropanoid biosynthesis pathway, flavonoid biosynthesis metabolites, and anthocyanin biosynthesis pathway. Protein interaction network prediction revealed that glutathione-S-transferase (Q8L576) was connected to the proteins involved in the flavonoid and anthocyanin biosynthesis pathways, such as flavanone 3-dioxygenase 1 (Q7XM21), leucoanthocyanidin dioxygenase 1 (Q93VC3), 4-coumarate-CoA ligase 2 (Q42982), phenylalanine ammonia-lyase (P14717), chalcone synthase 1 (Q2R3A1), and 4-coumarate-CoA ligase 5 (Q6ZAC1). However, the expression of the most important anthocyanin biosynthesis gene was not altered, suggesting that only the transport mechanism was affected. Our findings highlight new insight into the anthocyanin pigmentation in black rice and provide new perspectives for future research.

Peonidin-3-O-glucoside and Resveratrol Increase the Viability of Cultured Human hFOB Osteoblasts and Alter the Expression of Genes Associated with Apoptosis, Osteoblast Differentiation and Osteoclastogenesis.

High-throughput RNA-sequencing can determine the impact of nutrients and their combinations on gene transcription levels in osteocytes, and clarify the biological pathways associated with their impact on bone tissues. Previously, we reported that resveratrol (RES) and peonidin-3-O-glucoside (POG) increased osteoblastogenesis, as well as reduced osteoclastogenesis in transgenic teleost fish models. Here, we perform whole-genome transcriptomic profiling of osteoblasts treated with POG or RES to provide a comprehensive understanding of alterations in gene expression and the molecular mechanisms involved. Cultured human fetal osteoblastic hFOB 1.19 cells were treated with the test compounds, and then RNA was used to prepare RNA-seq libraries, that were sequenced using a NovaSeq 6000. Treatment with POG or RES increased osteoblast proliferation and reduced apoptosis. Transcriptomic profiling showed that of the 29,762 genes investigated, 3177 were differentially expressed (1481 upregulated, 1696 downregulated, FDR ≤ 0.05) in POG-treated osteoblasts. In the RES-treated osteoblasts, 2288 genes were differentially expressed (DGEs, 1068 upregulated, 1220 downregulated, FDR ≤ 0.05). Ingenuity® Pathway Analysis (IPA) of DGEs from RES or POG-treated osteoblasts revealed significant downregulation of the apoptosis, osteoarthritis and HIF1α canonical pathways, and a significant reduction in Rankl mRNA expression. The data suggest that RES and POG have both anabolic and anticlastogenic effects.

Study of the scale isolation of anthocyanins from blue corn by flash chromatography

In the current work, a flash chromatography method was developed to separate the main anthocyanins of blue corn; cyanidin-3-glucoside (Cy3G), peonidin-3-glucoside (Pn3G), and cyanidin-3-(6-malonylglucoside) (Cy3MG). These anthocyanins were identified by mass spectroscopy analysis. The implemented method consisted of the isocratic elution in a two-step mixture of methanol: water: acetic acid as the mobile phase (easy to remove) and C18 resin as the stationary phase. In the chromatographic method, different elution conditions were evaluated. The better condition to separate the anthocyanins with glycoside was 5% methanol and 10% acetic acid for 200 minutes of elution, followed by 200 minutes with 25% methanol and 2.5% acetic acid for the malonylglucoside forms. From the chromatograms prepared, the efficiency of the chromatographic separation was evaluated by calculating the parameters: retention factor (), selectivity (), number of theoretical plates (), and resolution (). The optimal values were determined as follows: Cy3G and Cy3MG were as follows: for Cy3G, the rretention factir (k) was dtermined to be 30.2, the selectivity (α) was 1.55, the number of theorical plates (N) was 202, and the resolution (Rs) was 1.09. For Cy3MG, the corresponding values were; k = 104.9, α =1.21, N=522, and Rs 0.093. These parameters are useful to implement separation processes of anthocyanins from other sources of pigmented corn or even others containing anthocyanins.

Comparative Metabolomic Analysis of the Nutritional Aspects from Ten Cultivars of the Strawberry Fruit.

Strawberry (Fragaria × ananassa) is among the most widely cultivated fruits with good taste and rich nutrients. Many strawberry species, including white strawberries, are planted all over the world. The metabolic profiles of strawberry and distinctions among different cultivars are not fully understood. In this study, non-targeted metabolomics based on UHPLC-Q-Exactive Orbitrap MS was used to analysis the metabolites in 10 strawberry species. A total of 142 compounds were identified and were divided into six categories. Tochiotome may differ most from the white strawberry (Baiyu) by screening 72 differential metabolites. Histidine, apigenin, cyanidin 3-glucoside and peonidin 3-glucoside had potential as biomarkers for distinguishing Baiyu and another 11 strawberry groups. Amino acid metabolisms, anthocyanin biosynthesis and flavonoid biosynthesis pathways were mainly involved in the determination of the nutrition distinctions. This research contributes to the determination of the nutrition and health benefits of different strawberry species.

Peonidin-3-O-Glucoside from Purple Corncob Ameliorates Nonalcoholic Fatty Liver Disease by Regulating Mitochondrial and Lysosome Functions to Reduce Oxidative Stress and Inflammation.

A frequent chronic liver condition across the world is nonalcoholic fatty liver disease (NAFLD). Oxidative stress caused by lipid accumulation is generally considered to be the main cause of NAFLD. Anthocyanins can effectively inhibit the production of reactive oxygen species and improve oxidative stress. In this work, six major anthocyanins were separated from purple corncob by semi-preparative liquid chromatography. The effects of the 6 kinds of anthocyanins against NAFLD were investigated using a free fatty acid (FFA)-induced cell model. The results showed that peonidin 3-O-glucoside (P3G) can significantly reduce lipid accumulation in the NAFLD cell model. The treatment with P3G also inhibited oxidative stress via inhibiting the excessive production of reactive oxygen species and superoxide anion, increasing glutathione levels, and enhancing the activities of SOD, GPX, and CAT. Further studies unveiled that treatment with P3G not only alleviated inflammation but also improved the depletion of mitochondrial content and damage of the mitochondrial electron transfer chain developed concomitantly in the cell model. P3G upregulated transcription factor EB (TFEB)-mediated lysosomal function and activated the peroxisome proliferator-activated receptor alpha (PPARα)-mediated peroxisomal lipid oxidation by interacting with PPARα possibly. Overall, this study added to our understanding of the protective effects of purple corn anthocyanins against NAFLD and offered suggestions for developing functional foods containing these anthocyanins.

Processing affects (decreases or increases) metabolites, flavonoids, black rice pigment, and total antioxidant capacity of purple glutinous rice grains.

The objective of this study was to understand the effects of processing on metabolites, flavonoids, black rice pigments and total antioxidant capacity of purple grains. The biochemical indicators and metabolites were determined before and after processing of purple grains. The results showed that the total antioxidant capacity, total phenol (TP), flavonoid (PD), oligomeric proanthocyanidin (OPC), ascorbic acid (AsA), cyanidin-3-O-glucoside (C3OG), peonidin 3-glucoside (P3G) contents of purple grains were greatly decreased after brown rice grains were processed into polished rice grains. The TP, PD, OPC, AsA, C3OG, and P3G of Yangzinuo No.1 brown rice (YZN1_B) or polished rice grains (YZN1_H) were higher than those of Yangzinuo No.2 brown rice (YZN2_B) or polished rice grains (YZN2_H). 154 differential metabolites (DMs) were identified between YZN1_B and YZN1_H. 52 DMs were identified between YZN2_B and YZN2_H. Citric acid and isocyanate are key metabolites affected during processing and have good correlations with various biochemical indicators.

Light Quality Modulates Growth, Triggers Differential Accumulation of Phenolic Compounds, and Changes the Total Antioxidant Capacity in the Red Callus of Vitis davidii.

Light quality is one of the key elicitors that directly affect plant cell growth and biosynthesis of secondary metabolites. In this study, the red callus of spine grape was cultured under nine light qualities (namely, dark, white, red, yellow, blue, green, purple, warm-yellow, and warm-white light). The effects of different light qualities were studied on callus growth, accumulation of phenolic compounds, and total antioxidant capacity of the red callus of spine grape. The results showed that blue and purple light induced increased red coloration in the callus, whereas yellow light induced the greatest callus proliferation. Among all of the light quality treatments, darkness treatment downregulated the contents of phenolic compounds, whereas blue light was the treatment most conducive to the accumulation of total phenolics. White, blue, and purple light induced increased anthocyanin accumulation. Mixed-wavelength light was beneficial to the accumulation of flavonoids. Blue and purple light were conducive to the accumulation of proanthocyanidins. A further study showed that cyanidin 3-glucoside (Cy3G) and peonidin 3-glucoside (P3G) were the main anthocyanin components in the callus, and blue, purple, and white light treatments promoted their accumulation, whereas flavan-3-ols and flavonols were the main components of non-anthocyanin phenolics, and their accumulation changed in response to not only light quality but also culture duration. The total antioxidant capacity of the callus cultures changed significantly in response to different light qualities. These results will provide evidence for an abiotic elicitor strategy to stimulate callus growth and enhance the accumulation of the main phenolic compounds in the red callus of spine grape.

Comparative analysis of bioactive-phytochemical characteristics, antioxidants activities, and anti-inflammatory properties of selected black rice germ and bran (Oryza sativa L.) varieties.

Black rice has numerous health benefits and one of the well-known functional foods throughout the world. To encourage the increasing trend of the consumer interest in health-promoting functional foods, special varieties of rice have been developed offering greater nutrient values and exhibiting biological activities that are beneficial to the consumer. In this study, we aimed to evaluate the associations of the phytochemical contents, antioxidants, and anti-inflammatory properties among eight selected black rice germ and bran extracts (BR extracts) from 4 non-glutinous and 4 glutinous rice varieties. Accordingly, glutinous BR extracts possessed higher degree of Cyanidin-3-O-glucoside (C3G), Peonidin-3-O-glucoside (P3G) contents, antioxidant and anti-inflammatory properties than the non-glutinous BR extracts. Pearson’s correlation indicated that the amount of C3G in the BR extracts had a strong positive association with the antioxidant properties (DPPH; r = 0.846, ABTS; r = 0.923, and FRAP; r = 0.958, p < 0.01). While P3G exhibited a strong positive association with the anti-inflammatory properties (r value = 0.717 and 0.797 for IL-6 and TNF-α inhibition, respectively, p < 0.05). Lastly, the principal component analysis (PCA) categorized the black rice varieties into three groups: Group A with high C3G content and superior antioxidant properties, Groups B with a high amount of P3G and potent anti-inflammatory properties, and Group C with a lower amount of phytochemical contents and less potent bioactivities. Overall, the outcomes of this study could provide vital information to food industries in selecting the variety of black rice for the functional food based on the anthocyanin contents that could benefit to consumers for new normal healthy lifestyle.

PhUGT78A22, a novel glycosyltransferase in Paeonia ‘He Xie’, can catalyze the transfer of glucose to glucosylated anthocyanins during petal blotch formation

BackgroundFlower color patterns play an important role in the evolution and subsequent diversification of flowers by attracting animal pollinators. This interaction can drive the diversity observed in angiosperms today in many plant families such as Liliaceae, Paeoniaceae, and Orchidaceae, and increased their ornamental values. However, the molecular mechanism underlying the differential distribution of anthocyanins within petals remains unclear in Paeonia.ResultsIn this study, we used an intersectional hybrid between the section Moutan and Paeonia, hereafter named Paeonia ‘He Xie’, which has purple flowers with dark purple blotches. After Ultra-high performance liquid chromatography-diode array detector (UPLC-DAD) analysis of blotched and non-blotched parts of petals, we found the anthocyanin content in the blotched part was always higher than that in the non-blotched part. Four kinds of anthocyanins, namely cyanidin-3-O-glucoside (Cy3G), cyanidin-3,5-O-glucoside (Cy3G5G), peonidin-3-O-glucoside (Pn3G), and peonidin-3,5-O-glucoside (Pn3G5G) were detected in the blotched parts, while only Cy3G5G and Pn3G5G were detected in the non-blotched parts. This suggests that glucosyltransferases may play a vital role in the four kinds of glucosylated anthocyanins in the blotched parts. Moreover, 2433 differentially expressed genes (DEGs) were obtained from transcriptome analysis of blotched and non-blotched parts, and a key UDP-glycosyltransferase named PhUGT78A22 was identified, which could use Cy3G and Pn3G as substrates to produce Cy3G5G and Pn3G5G, respectively, in vitro. Furthermore, silencing of PhUGT78A22 reduced the content of anthocyanidin 3,5-O-diglucoside in P. ‘He Xie’.ConclusionsA UDP-glycosyltransferase, PhUGT78A22, was identified in P. ‘He Xie’, and the molecular mechanism underlying differential distribution of anthocyanins within petals was elucidated. This study provides new insights on the biosynthesis of different kinds of anthocyanins within colorful petals, and helps to explain petal blotch formation, which will facilitate the cultivar breeding with respect to increasing ornamental value. Additionally, it provides a reference for understanding the molecular mechanisms responsible for precise regulation of anthocyanin biosynthesis and distribution patterns.

Investigation of flavonoid components and their associated antioxidant capacity in different pigmented rice varieties

Black and red rice are flavonoid-rich and nutritious. However, comprehensive information of flavonoid components in different pigmented rice varieties remain unclear. Here, we analyze the differences in flavonoid components in black, red, and white rice by ultra-high-performance liquid chromatography (UPLC) and metabolome analysis. Cyanidin-3-glucoside (Cy-3-G), peonidin-3-glucoside (Pe-3-G), quercetin, dihydromyricetin, naringin, and taxifolin contents were significantly high in black rice. By contrast, catechin and epicatechin contents were substantial in red rice. Cy-3-G was the main anthocyanin and its content was more than four times that of Pe-3-G in black rice varieties. Trifolin hardly showed specificity and exhibited a high content in all rice varieties. The antioxidant capacity of the red and black rice varieties was significantly higher than that of white rice. Moreover, in black and red rice, quercetin and catechin respectively exhibited the strongest antioxidant capacity and a good contribution toward the total flavonoid content, and mean time, white rice possessed antioxidant capacity main derived from quercetin and trifolin. Besides, the study also found that there was slightly inconsistent results between UPLC and metabolome, because certain components with trace by metabolome were not detected by UPLC, but their combination could play a complementary role in the exploration of metabolic components to confirm the ingredients.

Optimization of the pulse electric field assisted extraction of black rice grain for antioxidant and sirtuin1 enzyme stimulation activities

Cyanidin-3-glucoside (C3G) and peonidin-3-glucoside (P3G) in black rice grain (BRG) demonstrate many beneficial health effects, including antioxidant and anti-aging properties. This research aimed to study on pulsed electric field assisted water extraction (PEF-AWE) on BRG using pre-treatment technique, which was determined for enhanced yields of C3G and P3G, antioxidant and sirtuin1 enzyme stimulation activities. The effects of operating parameters for PEF-AWE (intensity of electric field, X1: 3–5 kV/cm, number of pulse, X2: 1000–3000 pulse and BRG/water ratio, X3: 0.1–0.5 g/mL) were determined using regression analysis and optimized PEF-AWE condition using the response surface methodology. Regression models showed the intensity of electric field and BRG/water ratio were the strong influence parameters significantly on C3G (p < 0.01). The results highlighted optimized conditions of PEF-AWE followed by 5 kV/cm, 3000 pulse and 0.5 g/mL leading to achieve higher C3G (92.59 ± 4.79 mg/g) and P3G (4.59 ± 0.27 mg/g) than no pre-treatment by PEF process, approximately 60%. Additionally, PEF extracts of BRG can modulate the ability of surtuin1 enzyme to deacetylate substrate proteins (26.78 ± 0.50 FIR). Thus, PEF-AWE can be applied to produce BRG extract as natural antioxidant compound and functional ingredient.

The effects of different drying methods on the in vitro bioaccessibility of phenolics, antioxidant capacity, minerals and morphology of black ‘Isabel’ grape

The black Isabel grapes were dehydrated by hot-air drying (HAD), vacuum-drying (VD), ultrasound-assisted vacuum-drying (US-VD), freeze-drying (FD), and their physical properties, phenolic compounds, antioxidant capacities, and mineral content were determined before and after simulated in vitro digestion. Among drying methods, FD provided the highest retention of the phenolic compounds, whereas US-VD caused the highest loss. The changes of phenolics of grapes differed among the digestion phases depending on the state of grapes (fresh or dried) and the drying method. The chlorogenic acid was the major phenolic compound identified, followed by protocatechuic acid and catechin. The malvidin-3-O-glucoside was the major anthocyanin followed by 3-glucosides of petunidin, delphinidin, cyanidin, and peonidin in the fresh and FD samples. At the end of digestion, a significant decrease in the levels of phenolics, minerals and no presence of anthocyanins was observed. VD raisins exhibited a higher bioaccessibility index for most of the phenolic compounds. Potassium was the most bioaccessible mineral from grape samples. Our results together with the morphology of the grapes revealed that different microstructures created by drying and the disruption of the natural matrix would influence the release, transformation, and subsequent absorption of phenolics and minerals in the simulated digestion model.

New eco-friendly anti-corrosion inhibitor of purple rice bran extract for boiler quality steel: Experimental and theoretical investigations

In this present study, the extract of purple rice bran, an agricultural by-product enriched with antioxidants, was implemented as an eco-friendly natural corrosion inhibitor, often known as a green corrosion inhibitor. The inhibitor was extracted from purple rice bran using conventional extraction methods and characterized by HPLC, which revealed the presence of two prime compounds named cyaniding-3-glucoside (C3G) and peonidin-3-glucoside (P3G). This purple rice bran extract (PRBE) was used to inhibit as a green corrosion inhibitor on boiler quality (BQ) steel to assess its inhibition performance in 1 (M) HCl and 0.5 (M) H2SO4. The inhibition performance was investigated by some electrochemical techniques such as open circuit potential (OCP), potentiodynamic polarization test (PDP), electrochemical impedance spectroscopy (EIS). The investigation revealed that the maximum efficiency was 91.13% and 87.43% in the presence of 200 mgL−1 of PRBE in HCl and H2SO4 media, respectively. After applying various adsorption isotherm models, Langmuir isotherm was found as the best-fitted model that indicated both physical and chemical spontaneous adsorption of PRBE on the BQ surface. Both electrochemical and adsorption studies and indicated the PRBE as a mixed-type inhibitor. Various quantum chemical parameters were calculated to find out the active sites and the donor-acceptor interaction capability of the inhibitor molecules. The quantum chemical calculation was achieved with the help of density functional theory (DFT). The theoretical studies disclosed that P3G has a lower energy gap than C3G but higher dipole moment than C3G.

Optimisation of the dielectric barrier discharge to produce Riceberry rice flour retained with high activities of bioactive compounds using plasma technology

Riceberry rice is a hybrid rice that contains polyphenol compounds, anthocyanin, and high antioxidants. Plasma technology has been used to improve the quality of rice and rice flour. Some conditions of the plasma process can be altered to get the combination that can achieve maximum result. The present work aimed to identify the optimal combination of a plasma treatment condition by varying three variables: time (3 - 10 min), power (140 - 180 W), and oxygen flow rate (0.0 - 0.8 L/min) in improving the nutrient and antioxidant agent of Riceberry rice flour. The increase in time and power significantly increased the percenatge of the scavenging ability of the free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH), peonidin 3-glucoside, cyanidin 3-glucoside, and total anthocyanin; while the decrease in oxygen significantly decreased all the parameters analysed. The optimal plasma conditions were 7.87 min, 166 W, and 0.64 L/min of oxygen flow rate. Under this condition, the Riceberry rice flour consisted of 65.05% scavenging ability of DPPH, peonidin 3-glucoside of 45.21 mg/100 g, cyanidin 3-glucoside of 179.6 mg/100 g, and total anthocyanin of 225.81 mg/100 g. Finally, the plasma technique can improve the antioxidant activity and anthocyanin of Riceberry rice flour.

Structure and composition of blueberry fiber pectin and xyloglucan that bind anthocyanins during fruit puree processing

Blueberry is a well-known source of antioxidants and prebiotic dietary fiber yet the fate of these health-beneficial ingredients during fruit processing it is not understood. Detailed composition and structure of blueberry pomace (PF) remaining after commercial blueberry fruit puree processing, as well as the water soluble and water insoluble fractions, were determined. The PF was comprised of dietary fiber (60.8%) that was largely insoluble (46.2% vs. 14.6% soluble dietary fiber) pectin, xyloglucan, arabinoxylan and mannan polysaccharides, fructose (11.22%) and glucose (10.37%) free sugars, protein (9%), fat (5%), and anthocyanins (6444.5 μg/g). The most abundant anthocyanins detected in PF were malvidin 3-arabinoside and peonidin 3-glucoside and the pectin was determined to be methyl-esterified and acetylated rhamnogalacturonan I with a 4,5-unsaturated function at the non-reducing end based on oligosaccharide structural analysis. Blueberry PF xyloglucan oligosaccharide side chain structures included xylose, arabinose and galactose consistent with arabino-xyloglucan structure. Microwave-assisted extraction of blueberry PF (pH 2 for 10 min at 80 °C) was performed to more clearly elucidate pectin structure, and revealed a pectin polymer with high molar mass (1072 kDa) and viscosity that was dependent upon the molar mass. A random coil shape was confirmed for both the blueberry PF and microwave extracted blueberry pectin, which agreed with previous reports that flexible blueberry pectin contributes to strong anthocyanin binding. In summary, the blueberry pomace anthocyanin content was slightly higher than that reported for fresh whole blueberry fruit, which suggests that most blueberry anthocyanins adhered to the pomace fiber, and most likely the insoluble pectin, during and after processing.