Identification and quantification of anthocyanins in purple-fleshed sweet potato leaves

Harnessing the health benefits of purple and yellow-fleshed sweet potatoes: Phytochemical composition, stabilization methods, and industrial utilization- A review

Purple-fleshed sweet potato (PFSP) and yellow-fleshed sweet potato (YFSP) are crops highly valued for their nutritional benefits and rich bioactive compounds. These compounds include carotenoids, flavonoids (including anthocyanins), and phenolic acids etc. which are present in both the leaves and roots of these sweet potatoes. PFSP and YFSP offer numerous health benefits, such as antioxidant, anti-inflammatory, anti-cancer, and neuroprotective properties. The antioxidant activity of these sweet potatoes holds significant potential for various industries, including food, pharmaceutical, and cosmetics. However, a challenge in utilizing PFSP and YFSP is their susceptibility to rapid oxidation and color fading during processing and storage. To address this issue and enhance the nutritional value and shelf life of food products, researchers have explored preservation methods such as co-pigmentation and encapsulation. While YFSP has not been extensively studied, this review provides a comprehensive summary of the nutritional value, phytochemical composition, health benefits, stabilization techniques for phytochemical, and industrial applications of both PFSP and YFSP in the food industry. Additionally, the comparison between PFSP and YFSP highlights their similarities and differences, shedding light on their potential uses and benefits in various food products.

Accumulation patterns of flavonoids and phenolic acids in different colored sweet potato flesh revealed based on untargeted metabolomics

Sweet potatoes are rich in flavonoids and phenolic acids, showing incomparable nutritional and health value. In this investigation, we comprehensively analyzed the secondary metabolite profiles in the flesh of different-colored sweet potato flesh. We determined the metabolomic profiles of white sweet potato flesh (BS), orange sweet potato flesh (CS), and purple sweet potato flesh (ZS) using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The CS vs. BS, ZS vs. BS, and ZS vs. CS comparisons identified a total of 4447 secondary metabolites, including 1540, 1949, and 1931 differentially accumulated metabolites. Among them, there were significant differences in flavonoids and phenolic acids. There were 20 flavonoids and 13 phenolic acids that were common differential metabolites among the three comparison groups. The accumulation of paeoniflorin-like and delphinidin-like compounds may be responsible for the purple coloration of sweet potato flesh. These findings provide new rationale and insights for the development of functional foods for sweet potatoes.

List of compounds

Kaempferol (PubChem CID: 5280863); Peonidin 3-(6"-p-coumarylglucoside) (PubChem CID: 44256849); Swerchirin (PubChem CID: 5281660); Trilobatin (PubChem CID: 6451798); 3-Geranyl-4-hydroxybenzoate (PubChem CID: 54730540); Eupatorin (PubChem CID: 97214); Icaritin (PubChem CID: 5318980); Isorhamnetin (PubChem CID: 5281654); Glucoliquiritin apioside (PubChem CID: 74819335); Brazilin (PubChem CID: 73384).

Chitosan/polyvinyl alcohol food packaging incorporated with purple potato anthocyanins and nano-ZnO: Application on the preservation of hairtail (Trichiurus haumela) during chilled storage

The objective of this work was to evaluate the potential application of chitosan/PVA food packaging films incorporating nano-ZnO and purple potato anthocyanins for preserving chilled hairtail pieces. The hairtail pieces were packaged with chitosan/PVA (CP) and chitosan/PVA/nano-ZnO/purple potato anthocyanins (CPZP), respectively, and Control named without any packaging. The changes in pH, total volatile basic nitrogen (TVB-N), total bacterial colony (TVC), thiobarbituric acid (TBA), color value, and sensory evaluation scores of hairtail pieces were periodically determined. Notably, pH, TVC, TVB-N and TBA values of CPZP group on day 15 were 11.67 %, 23.71 %, 80.73 %, and 35.07 %, respectively, lower than Control group. In addition, CPZP group also performed the best in color and sensory evaluation. These results indicated that CPZP, an active food packaging, could extend the shelf-life of hairtail at least 6 days. Overall, chitosan/PVA food films incorporated with nano-ZnO and purple potato anthocyanins (180 mg/100 mL) provides a potential application in food preservation.

Proximate Composition, Health Benefits, and Food Applications in Bakery Products of Purple-Fleshed Sweet Potato (Ipomoea batatas L.) and Its By-Products: A Comprehensive Review

Ipomoea batatas (L.) Lam is a dicotyledonous plant originally from tropical regions, with China and Spain acting as the main producers from outside and within the EU, respectively. The root, including only flesh, is the edible part, and the peel, leaves, stems, or shoots are considered by-products, which are generated due to being discarded in the field and during processing. Therefore, this study aimed to perform a comprehensive review of the nutritional value, phytochemical composition, and health-promoting activities of purple-fleshed sweet potato and its by-products, which lead to its potential applications in bakery products for the development of functional foods. The methodology is applied to the selected topic and is used to conduct the search, review abstracts and full texts, and discuss the results using different general databases. The studies suggested that purple-fleshed sweet potato parts are characterized by a high content of essential minerals and bioactive compounds, including anthocyanins belonging to the cyanidin or the peonidin type. The flesh and leaves are also high in phenolic compounds and carotenoids such as lutein and β-carotene. The high content of phenolic compounds and anthocyanins provides the purple-fleshed sweet potato with high antioxidant and anti-inflammatory power due to the modulation effect of the transcription factor Nrf2 and NF-kB translocation, which may lead to protection against hepatic and neurological disorders, among others. Furthermore, purple-fleshed sweet potato and its by-products can play a dual role in food applications due to its attractive color and wide range of biological activities which enhance its nutritional profile. As a result, it is essential to harness the potential of the purple-fleshed sweet potato and its by-products that are generated during its processing through an appropriate agro-industrial valorization system.

Exploring the Potential of Anthocyanin-Based Edible Coatings in Confectionery-Temperature Stability, pH, and Biocapacity

This study aims to develop purple-coloured polymeric coatings using natural anthocyanin and desoxyanthocianidins (3-DXA) colourants for application to chocolate almonds. The objective is to achieve a stable and uniform colour formulation throughout processing and storage, enhancing the appearance and durability of the almonds to appeal to health-conscious consumers and align with market demands. Plant materials like sweet potato pulp, sweet potato peel, radish peel, black carrot, and sorghum were employed to obtain the desired purple hue. Anthocyanidins and 3-DXA were extracted from the matrices using solvent extraction and ultrasound-assisted methods at different pH values. High-performance liquid chromatography with diode array detection (HPLC-DAD) and high-resolution tandem mass spectrometry (HRMS/MS) were used to identify the compounds in the extracts. The highest antioxidant capacities, as measured by the DPPH• and FRAP methods, were observed in purple sweet potato and dye factory extracts, respectively; meanwhile, sorghum extract inhibited both α-amylase and α-glucosidase, indicating its potential for managing postprandial hyperglycemia and type 2 diabetes. The degradation kinetics of coloured coatings in sugar syrup formulations with anthocyanins and 3-DXA revealed that locust bean gum offered the best colour stabilization for plant extracts, with sorghum extracts showing the highest and black carrot extracts the lowest colour variation when coated with Arabic gum. Sweet potato pulp extracts exhibited less colour variation in sugar pastes, both with and without blue spirulina dye, compared to factory dye, highlighting their potential as a more stable and suitable alternative for colouring purple almonds, particularly over a five-month storage period. This study supports sustainable practices in the confectionery industry while aligning with consumer preferences for healthier and environmentally friendly products.

The Effect of Combined Elicitation with Light and Temperature on the Chlorogenic Acid Content, Total Phenolic Content and Antioxidant Activity of Berula erecta in Tissue Culture

Chlorogenic acid is one of the most prominent bioactive phenolic acids with great pharmacological, cosmetic and nutritional value. The potential of Berula erecta in tissue culture was investigated for the production of chlorogenic acid and its elicitation combined with light of different wavelengths and low temperature. The content of chlorogenic acid in the samples was determined by HPLC-UV, while the content of total phenolic compounds and the antioxidant activity of their ethanol extracts were evaluated spectrophotometrically. The highest fresh and dry biomasses were obtained in plants grown at 23 °C. This is the first study in which chlorogenic acid has been identified and quantified in Berula erecta. The highest chlorogenic acid content was 4.049 mg/g DW. It was determined in a culture grown for 28 days after the beginning of the experiment at 12 °C and under blue light. The latter also contained the highest content of total phenolic compounds, and its extracts showed the highest antioxidant activity. Berula erecta could, potentially, be suitable for the in vitro production of chlorogenic acid, although many other studies should be conducted before implementation on an industrial scale.

Influence of Harvesting Stages on Phytonutrients and Antioxidant Properties of Leaves of Five Purple-Fleshed Sweet Potato (Ipomoea batatas) Genotypes

Sweet potatoes (Ipomoea batatas) are highly profitable, contribute to food security, and their leaves rich in phytonutrients. This study examined the optimal leaf harvesting stage by harvesting newly formed leaves (leaves 1 to 5) to achieve the highest concentration of carotenoids, phenolic compounds, antioxidant properties and mineral content. Leaves of five purple-fleshed sweet potato genotypes '2019-11-2' and '2019-1-1', 'Purple-purple', and from the USA '08-21P' and '16-283P' were harvested based on tuber life cycle [vegetative 8 weeks after planting (VS-8WAP), tuber initiation (TIS-12WAP), and tuber maturation phases (TMS-16WAP)]. At the 8WAP stage, leaves of genotype '2019-11-2' had the highest concentrations of cyanidin-caffeoyl-sophoroside-glucoside (17.64 mg/kg), cyanidin-caffeoyl-feruloyl-sophoroside-glucoside (41.51 mg/kg), peonidin-caffeoyl-hydroxybenzoyl-sophoriside-glucoside (45.25 mg/kg), and peonidin caffeoyl-feruloyl-sophoriside-glucoside (24.47 mg/kg), as well as antioxidant scavenging activity. In contrast, 'Purple-purple' harvested at TIS-12WAP showed the highest concentration of caffeoylquinic acid derivatives. Zeaxanthin, lutein, all trans-β-carotene, and cis-β-carotene are the most abundant carotenoids in genotype '08-21P' at VS-8WAP. As a result, local genotypes '2019-11-2' harvested at 8WAP and 'Purple-purple' harvested at 12WAP are potential sources of anthocyanins and caffeoylquinic acid derivatives. Conversely, USA's genotype '08-21P' at the VS-8WAP stage is an excellent source of carotenoids. The leaves of USA's '08-21P' genotype and the local '2019-11-2' genotype at TMS-16WAP exhibited the highest content of Fe and Mn, respectively. The study identified the optimal leaf stage for consumption of leaves and for use as a functional ingredient.

Reclaiming Agriceuticals from Sweetpotato (Ipomoea batatas [L.] Lam.) By-Products

Sweetpotato (SP, Ipomoea batatas [L.] Lam.) is a globally significant food crop known for its high nutritional and functional values. Although the contents and compositions of bioactive constituents vary among SP varieties, sweetpotato by-products (SPBs), including aerial parts, storage root peels, and wastes generated from starch processing, are considered as excellent sources of polyphenols (e.g., chlorogenic acid, caffeoylquinic acid, and dicaffeoylquinic acid), lutein, functional carbohydrates (e.g., pectin, polysaccharides, and resin glycosides) or proteins (e.g., polyphenol oxidase, β-amylase, and sporamins). This review summarises the health benefits of these ingredients specifically derived from SPBs in vitro and/or in vivo, such as anti-obesity, anti-cancer, antioxidant, cardioprotective, and anti-diabetic, evidencing their potential to regenerate value-added bio-products in the fields of food and nutraceutical. Accordingly, conventional and novel technologies have been developed and sometimes combined for the pretreatment and extraction processes aimed at optimising the recovery efficiency of bioactive ingredients from SPBs while ensuring sustainability. However, so far, advanced extraction technologies have not been extensively applied for recovering bioactive compounds from SPBs except for SP leaves. Furthermore, the incorporation of reclaimed bioactive ingredients from SPBs into foods or other healthcare products remains limited. This review also briefly discusses current challenges faced by the SPB recycling industry while suggesting that more efforts should be made to facilitate the transition from scientific advances to commercialisation for reutilising and valorising SPBs.

Characterisation of acylated anthocyanins from red cabbage, purple sweet potato, and Tradescantia pallida leaves as natural food colourants by HPLC-DAD-ESI(+)-QTOF-MS/MS and ESI(+)-MSn analysis

Anthocyanins in red cabbage, sweet potato, and Tradescantia pallida leaves were characterised. A total of 18 non-, mono-, and diacylated cyanidins was identified in red cabbage by high performance liquid chromatography-diode array detection coupled to high-resolution and multi-stage mass spectrometry. Sweet potato leaves contained 16 different cyanidin- and peonidin glycosides being predominantly mono- and diacylated. In T. pallida leaves, the tetra-acylated anthocyanin tradescantin prevailed. The large proportion of acylated anthocyanins resulted in a superior thermal stability during heating of aqueous model solutions (pH 3.0) coloured with red cabbage and purple sweet potato extracts as compared to that of a commercial Hibiscus-based food dye. However, their stability was still outperformed by that of the most stable Tradescantia extract. Comparing vis spectra from pH 1-10, the latter had an additional, uncommon absorption maximum at approx. 585 nm at slightly acidic to neutral pH values, yielding intensely red to purple colours.

Research progress of anthocyanin prebiotic activity: A review

BACKGROUND

Anthocyanins are a kind of flavonoids and natural water-soluble pigments, which endow fruits, vegetables, and plants with multiple colors. They are important source of new products with prebiotic activity. However, there is no systematic review documenting prebiotic activity of anthocyanins and their structural analogues. This study aims to fill this gap in literature.

PURPOSE

The objective of this review is to summarize and evaluate the prebiotic activity of anthocyanin's, and discuss the physical and molecular modification methods to improve their biological activities.

STUDY DESIGN AND METHODS

In this review, the databases (PubMed, Google Scholar, Web of Science, Researchgate and Elsevier) were searched profoundly with keywords (anthocyanin's, prebiotics, probiotics, physical embedding and molecular modification).

RESULTS

A total of 34 articles were considered for reviewing. These studies approved that anthocyanins play an important role in promoting the proliferation of probiotics, inhibiting the growth of harmful bacteria and improving the intestinal environment. In addition, physical embedding and molecular modification have also been proved to be effective methods to improve the prebiotic activity of anthocyanins. Anthocyanins could promote the production of short chain fatty acids, accelerate self degradation and improve microbial related enzyme activities to promote the proliferation of probiotics. They inhibited the growth of harmful bacteria by inhibiting the expression of harmful bacteria genes, interfering with the role of metabolism related enzymes and affecting respiratory metabolism. They promoted the formation of a complete intestinal barrier and regulated the intestinal environment to keep the body healthy. Physical embedding, including microencapsulation and colloidal embedding, greatly improved the stability of anthocyanins. On the other hand, molecular modification, especially enzymatic modification, significantly improved the biological activities (antioxidant, prebiotic activity and so on) of anthocyanins.

CONCLUSION

All these research results displayed by this review indicate that anthocyanins are a useful tool for developing prebiotic products. The better activities of the new anthocyanins formed by embedding and modification may make them become more effective raw materials. Our review provides a scientific basis for the future research and application of anthocyanins.

Total Phenolics and Anthocyanins Contents and Antioxidant Activity in Four Different Aerial Parts of Leafy Sweet Potato (Ipomoea batatas L.)

Leafy sweet potato (Ipomoea batatas L.) is an excellent source of nutritious greens and natural antioxidants, but reports on antioxidants content and activity at buds, leaves, petioles, and stems are scarce. Therefore, the total phenolics content (TPC), total anthocyanins content (TAC), and antioxidant activity (assessed by DPPH and ABTS radical scavenging activities and ferric reducing antioxidant power (FRAP)) were investigated in four aerial parts of 11 leafy sweet potato varieties. The results showed that varieties with pure green aerial parts, independently of the part analyzed, had higher TPC, FRAP, and ABTS radical scavenging activities. The green-purple varieties had a significantly higher TAC, while variety GS-17-22 had the highest TAC in apical buds and leaves, and variety Ziyang in petioles and stems. Among all parts, apical buds presented the highest TPC and antioxidant capacity, followed by leaves, petioles, and stems, while the highest TAC level was detected in leaves. The TPC was positively correlated with ABTS radical scavenging activity and FRAP in all parts studied, whereas the TAC was negatively correlated with DPPH radical scavenging activity. Collectively, the apical buds and leaves of sweet potato had the higher levels of nutritional values. These results would provide reference values for further breeding of leafy sweet potatoes.

Changes in Antioxidant Properties and Phenolics in Sweet Potatoes (Ipomoea batatas L.) Due to Heat Treatments

Processing is one of the most crucial factors affecting polyphenol content in foods. Therefore, the study is aimed at the evaluation of heat treatment effects (microwaving, steaming, baking, and boiling) on the content of chlorogenic acids, total polyphenols, and antioxidant activity of three varieties of sweet potato with different flesh colors (Beauregard—orange-fleshed, O’Henry—white-fleshed, 414-purple—purple-fleshed). According to high performance liquid chromatography analysis, chlorogenic acid was the predominant chlorogenic acid in sweet potatoes. Obtained results also suggested the purple-fleshed variety (414-purple) had significantly (p < 0.05) higher total polyphenol content and thus the highest antioxidant activity. Heat treatment positively influenced the chlorogenic acid content, total polyphenols, and antioxidant activity of sweet potatoes. Among the used methods, steaming had the greatest effect on the chlorogenic acids and total polyphenols, while microwaved samples showed the highest antioxidant activity (DPPH). The content of chlorogenic acids and total polyphenols decreased in the order of steaming > baking > microwaving > boiling > raw. However, the individual varieties differed not only in the flesh color but also in the reaction to the used heat treatment methods. Spearman’s correlation coefficient showed a strong correlation between chlorogenic acid and antioxidant activity.

Pigment-Related Mutations Greatly Affect Berry Metabolome in San Marzano Tomatoes

The study describes the alterations in metabolomic profiles of four tomato fruit mutations introgressed into Solanum lycopersicum cv. San Marzano, a well-known Italian traditional variety. Three lines carrying variants affecting the content of all pigments, high pigment-1 (hp-1), hp-2, pigment diluter (pd), and a combination of Anthocyanin fruit and atroviolaceum (Aft_atv), were selected, and characterized. Biochemical analysis of 44 non-polar, 133 polar, and 65 volatile metabolites in ripe fruits revealed a wide range of differences between the variant lines and the recurrent parent San Marzano. Among non-polar compounds, many carotenoids, plastoquinones, and tocopherols increased in the fruit of high pigment lines, as well as in Aft_atv, whose β-carotene levels increased too. Interestingly, pd displayed enriched levels of xanthophylls (all-trans-neoxanthin and luteoxanthin) but, simultaneously, decreased levels of α-and β-/γ-tocopherols. Looking at the metabolites in the polar fraction, a significant decrease in sugar profile was observed in hp-1, pd, and Aft_atv. Conversely, many vitamins and organic acids increased in the hp-2 and Aft_atv lines, respectively. Overall, phenylpropanoids was the metabolic group with the highest extent of polar changes, with considerable increases of many compounds mainly in the case of Aft_atv, followed by the pd and hp-2 lines. Finally, several flavor-related compounds were found to be modified in all mutants, mostly due to increased levels in many benzenoid, lipid, and phenylalanine derivative volatiles, which are associated with sweeter taste and better aroma. Construction of metabolic maps, interaction networks, and correlation matrices gave an integrated representation of the large effect of single variants on the tomato fruit metabolome. In conclusion, the identified differences in the mutated lines might contribute to generating novel phenotypes in the traditional San Marzano type, with increased desirable nutraceutical and organoleptic properties.

Effects and mechanism of natural phenolic acids/fatty acids on copigmentation of purple sweet potato anthocyanins

Anthocyanins are attractive alternatives to colorants; however, their low color stability hinders practical application. Copigmentation can enhance both the color intensity and color stability of complexes. Herein, we report an investigation of copigmentation reactions between purple sweet potato anthocyanins (PSA1) and phenolic acids (tannic, ferulic, and caffeic acids) or fatty acids (tartaric and malic acids) at pH 3.5. The effects of the mole ratios of the copigment and the reaction temperature were examined. In addition, quantum mechanical computations were performed to investigate molecular interactions. The optimum PSA:copigment molar ratio was found to be 1:100. The strongest bathochromic and hyperchromic effects were observed for copigmentation with tannic acid (Tan), which might be attributable to the fact that its HOMO-LUMO energy gap was the smallest among the investigated copigments, and because it has a greater number of phenolic aromatic and groups to form more van der Waals and hydrogen bond interactions. However, the formation of the PSA-caffeic acid (Caf) complex was accompanied by the greatest drop in enthalpy (−33.18 kJ/mol) and entropy (−74.55 kJ/mol), and this was the most stable complex at 90 °C. Quantum mechanical calculations indicated that hydrogen bonds and van der Waals force interactions contributed to the color intensification effect of copigmentation. These findings represent an advancement in our understanding of the properties of PSA, expanding the application scope of this natural product.

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Anthocyanin-phenolic/fatty acid copigmentation interactions were investigated.

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Copigment HOMO-LUMO gaps served as a copigmentation capability guide.

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Color changes in the presence of the acids were associated with structural effects.

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Copigmentation was mainly driven by hydrogen bonding and van der Waals interactions.

Ipomea batatas Leaf Powder from Cameroon: Antioxidant Activity and Antihyperlipidemic Effect in Rats Fed with a High-Fat Diet

The present study consists of analyzing the phytochemical composition of Ipomoea batatas leaf powders and evaluating their antihyperlipidemic effect on rats receiving a high-fat diet. Ipomoea batatas leaves were collected from four agroecological areas of Cameroon, and powders were obtained after washing, drying, grinding, and sieving. Standard analytical methods were used to determine the phytochemical composition of two varieties (IRAD-tib1yellow-V1 and IRAD-1112white-V2) from North Z1, Adamawa Z2, West Z3, Center Z4. The effect of I. batatas leaf powder on lipid metabolism was assessed in vivo by feeding different groups of rats with a high-fat diet supplemented with 5 and 10% of I. batatas leaf powder during 30 days. At the end of the experimentation, total cholesterols, triglycerides, LDL- (low-density lipoprotein-) cholesterol, HDL- (High-density lipoprotein-) cholesterol, ASAT (aspartate aminotransferase), ALAT (alanine aminotransferase), and creatinine were measured using commercial enzymatic kits (Spinreact, Spain). The results of phytochemical analysis of I. batatas leaf powders revealed that the total phenol content ranged from 660.173 mg GAE/100 gDW (Z1V2) to 657.76 mg GAE/100 gDW (Z3V2), the flavonoids content ranged from 282.25 mgEC/100 gDW (Z3V1) to 325.05 mgEC/100 gDW (Z4V2), and the anthraquinone content ranged from 324.05 mg/100 gDW (Z3V2) to 326.72 mg/100 gDW (Z4V2). The total antioxidant capacity ranged from 19.00 (Z1V1) to 23.48 mg AAE/gDW (Z3V2), while the IC₅₀ ranged from 1.58 mg/mL (Z1V1) to 3.08 mg/mL (Z3V2). Rats fed a high-fat diet and supplemented with 5 and 10% of I. batatas leaf powder showed a significant (p < 0.05) reduction in body weight compared to the control with a reduction rate ranging from 6 to 10%. The consumption of I. batatas leaf powder for 30 days significantly (p < 0.05) reduced serum total cholesterol, LDL-cholesterol, triglycerides, ALAT, and creatinine level. These results suggest the use of I. batatas leaves as a phytomedicine in the treatment of cardiovascular diseases.

pH-sensitive and antibacterial films developed by incorporating anthocyanins extracted from purple potato or roselle into chitosan/polyvinyl alcohol/nano-ZnO matrix: Comparative study

pH-sensitive and antibacterial films based on chitosan/polyvinyl alcohol/nano-ZnO (CPZ) containing anthocyanins extracted from purple potato (PPE) or roselle (RE) were developed. When incorporated with PPE or RE, the moisture contents and flexibility of film significantly reduced (P < 0.05), while mechanical resistance of film was significantly enhanced (P < 0.05). Water vapor permeability (WVP) of film was slightly influenced by the addition of PPE or RE (P > 0.05). CPZ-RE film exhibited darker color and lower light transmittance than CPZ-PPE film at the same incorporation level. CPZ-PPE and CPZ-RE films exhibited distinguishable color changes in different pH buffer solutions. CPZ-PPE films exhibited higher antibacterial activity against Escherichia coli and Staphylococcus aureus than CPZ-RE films. Moreover, film could effectively monitor spoilage degree of shrimp when film changed from purple to light-green. Our results suggested CPZ-PPE and CPZ-RE films have promising potential as active and smart packaging materials for applications in food industry.

Enzymatic and ultrasonic-assisted pretreatment in the extraction of bioactive compounds from Monguba (Pachira aquatic Aubl) leaf, bark and seed

The present study aims to characterize leaf, bark and seed of monguba in terms of their physicochemical and bioactive composition, and to determine total phenolic compounds (TPC) and total flavonoids (TF), well as their antioxidant activities (AA), of three organic solvent extracts with and without enzyme pretreatment by ultrasonic assisted extraction. Physicochemical composition was measured by pH, total titratable acidity, total soluble solids, moisture, ashes, lipids, crude protein, raw fiber, total carbohydrates, and water activity as well as, phytochemical composition analysis constituted of sugars, condensed (CT) and hydrolysable tannins (HT), carotenoids, total anthocyanins (TA), and organic acids contents. TPC and TF contents, and UHPLC/PDA/QDa flavonoids and phenolic acids quantification were performed for the solvent extracts. Antioxidant activity was determined by radical scavenging capacity assays (ABTS, DPPH, and ORAC), and reducing power assay (FRAP). Results showed that the leaf stood out with higher concentrations of ash, HT, TA and carotenoids; the bark with higher concentrations of raw fiber, total carbohydrates and organic acids (tartaric, quinic and 3.4-dihydroxybenzoic acids); in contrast, the seeds showed high concentrations of lipids, crude protein, sugars (fructose and sucrose), CT, and high values in all AA. The solvents significantly influenced the extraction of TPC and TF, highlighting ethanol. In general, the enzymatic treatments empowered the phenolic extraction and AA. The monguba seed extracts showed higher concentrations of hydroxycinnamic acids (chlorogenic acid, mainly), and flavanols (catechin and epicatechin), whereas the leaf extracts, flavanones (narigenin), flavonols (rutin, mainly) and flavones (acacetin). The bark extracts stood out for the presence of vanillin. The monguba seed extract can be used in functional foods production.

Validated liquid chromatography separation methods for identification and quantification of anthocyanins in fruit and vegetables: A systematic review

Food composition data are challenged by data availability and quality. Anthocyanins are the bright colored pigments found in fruits and vegetables with growing evidence for health benefits. For the estimation of anthocyanin content in the foods, it is imperative to find an ideal analytical method. To quantify anthocyanin components, liquid chromatography-based methods are commonly used. This review addresses the variability of liquid chromatography (LC) mass spectrometry (MS) methods for the identification and quantification of anthocyanins. Published studies for all years until February 2020 reporting LC methods for anthocyanins in fruits and vegetables were screened from 7660 studies. Only 29 studies met the eligibility criteria of method type and of these, only 13 studies reported a validated LC method. A wide range of validation parameters were identified including specificity, calibration, stability, and limits of detection. Differences in the sampling amounts for extraction were observed in all of the included studies. The quantification of multiple anthocyanin types without their corresponding analytical standards was observed in eight studies. The included 13 studies used reverse phase liquid chromatography separation with C₁₈ type or similar stationary phases and acidified aqueous or acidified aqueous: organic (usually methanol or acetonitrile) binary gradient mobile phases. Although all of the studies used mass spectrometry for identification, ultraviolet absorbance quantification was often used in conjunction with a photo-diode array (DAD/PDA) detector using reference standards where available. Extraction and preparation of samples remains the key concern for analysis as the oxidative stability of anthocyanins are a major impediment for accurate quantification of the components in foods. This review provides a summary of validated LC methods to assist analysts and nutritionists in the quantification of anthocyanin food components as the nutrient profiles of foods are challenged by the variability of the analytical methods.

Total Polyphenol Content, Antioxidant Activity, and Individual Phenolic Composition of Different Edible Parts of 4 Sweet Potato Cultivars

The quest to determine and use polyphenolic compounds present in fruits and vegetables as natural antioxidants has recently attracted much attention due to their beneficial health effects. In this study, the total polyphenol content (TPC), total flavonoid content (TFC), total anthocyanin content (TAC), antioxidant activity (AA), and individual polyphenol components of Simon No. 1, Yuzi No. 7, Shangshu 19, and Pushu 32 sweet potato cultivars (edible parts: leaf, stalk, stem, skin, and flesh) were investigated. TPC, TFC, and TAC values ranged from 440 ± 0.17-12080 ± 0.58 CAE mg/100 g DW, 94 ± 0.08-4210 ± 0.74 QE mg/100 g DW, and 7 ± 0.01-1010 ± 0.54 CGE mg/100 g DW, respectively. Yuzi No. 7 sweet potato cultivar contained significantly higher amounts of TPC, TFC, TAC, and AA in all its edible parts, followed by Pushu 32, Simon No. 1, and Shangshu 19 in that order. Regardless of the sweet potato cultivar used, TPC, TFC, and TAC of sweet potato leaves were significantly higher than those of other edible parts. High-performance liquid chromatography revealed 19 individual phenolic compounds. In general, 3,5-di- O-caffeoylquinic acid, astragalin, and cyanidin were the predominant phenolic acid, flavonoid, and anthocyanin compounds, respectively. The correlation analysis suggested that higher AA could be attributed to higher polyphenol content. Based on our results, edible parts of Yuzi No. 7 sweet potato cultivar presented the highest amounts of polyphenol content and AA suggesting the possibility of utilizing this cultivar by farmers and the food industry as a functional food product.

Transcriptome sequencing and whole genome expression profiling of hexaploid sweetpotato under salt stress

BACKGROUND

Purple-fleshed sweetpotato (PFSP) is one of the most important crops in the word which helps to bridge the food gap and contribute to solve the malnutrition problem especially in developing countries. Salt stress is seriously limiting its production and distribution. Due to lacking of reference genome, transcriptome sequencing is offering a rapid approach for crop improvement with promising agronomic traits and stress adaptability.

RESULTS

Five cDNA libraries were prepared from the third true leaf of hexaploid sweetpotato at seedlings stage (Xuzi-8 cultivar) treated with 200 mM NaCl for 0, 1, 6, 12, 48 h. Using second and third generation technology, Illumina sequencing generated 170,344,392 clean high-quality long reads that were assembled into 15,998 unigenes with an average length 2178 base pair and 96.55% of these unigenes were functionally annotated in the NR protein database. A number of 537 unigenes failed to hit any homologs which may be considered as novel genes. The current results indicated that sweetpotato plants behavior during the first hour of salt stress was different than the other three time points. Furthermore, expression profiling analysis identified 4, 479, 281, 508 significantly expressed unigenes in salt stress treated samples at the different time points including 1, 6, 12, 48 h, respectively as compared to control. In addition, there were 4, 1202, 764 and 2195 transcription factors differentially regulated DEGs by salt stress at different time points including 1, 6, 12, 48 h of salt stress. Validation experiment was done using 6 randomly selected unigenes and the results was in agree with the DEG results. Protein kinases include many genes which were found to play a vital role in phosphorylation process and act as a signal transductor/ receptor proteins in membranes. These findings suggest that salt stress tolerance in hexaploid sweetpotato plants may be mainly affected by TFs, PKs, Protein Detox and hormones related genes which contribute to enhance salt tolerance.

CONCLUSION

These transcriptome sequencing data of hexaploid sweetpotato under salt stress conditions can provide a valuable resource for sweetpotato breeding research and focus on novel insights into hexaploid sweetpotato responses to salt stress. In addition, it offers new candidate genes or markers that can be used as a guide to the future studies attempting to breed salt tolerance sweetpotato cultivars.

Quantitative Analysis of the Biologically Active Compounds Present in Leaves of Mexican Sweet Potato Accessions: Phenols, Flavonoids, Anthocyanins, 3,4,5-Tri-Caffeoylquinic Acid and 4-Feruloyl-5-Caffeoylquinic Acid

Sweet potato is one of the oldest crops cultivated in Mexico, and Mesoamerica is considered as a region with the greatest diversity of this species. Therefore, the present study focused on the evaluation of biologically active compounds, such as caffeoylquinic acid derivatives and flavonoid compounds, in sweet potato leaves of 200 accessions of the main producing regions of Mexico. The analysis of total phenol content (TPC) showed a great variability of concentrations among the examined accessions (54.41 to 284.64 mgTPC/g DW). Likewise, total flavonoid content (TFC) was determined and ranged from 10.01 to 40.17 mgTFC /g DW. Finally, total anthocyanin content (TAC) was evaluated and concentrations obtained varied from 0.05 to 0.98 mgTAC/g DW. Additionally, HPLC analysis of all 200 accessions demonstrated the presence of caffeic acid (CA), 5-caffeoylquinic acid (5-CQA), three isomers of di-caffeoylquinic acid (di-CCA) and 4-feruloyl-5-caffeoylquinic acid (4F-5CQA) in all test samples. Only 21 accessions tested showed the quantitative amount of 3,4,5-tri-caffeoylquinic acid (3,4,5-tri-CQA) with concentrations ranging from 44.73 to 193.22 mg/100 g DW and high content of 4F-5CQA (139.46 to 419.99 mg/100 g DW). The gathered data indicate that leaves of Mexican sweet potatoes are a promising source of phenolic compounds with remarkable nutraceutical potential.

Anthocyanin Accumulation in the Leaves of the Purple Sweet Potato (Ipomoea batatas L.) Cultivars

Sweet potato anthocyanins are water-soluble pigments with many physiological functions. Previous research on anthocyanin accumulation in sweet potato has focused on the roots, but the accumulation progress in the leaves is still unclear. Two purple sweet potato cultivars (Fushu No. 23 and Fushu No. 317) with large quantities of anthocyanin in the leaves were investigated. Anthocyanin composition and content were assessed with ultra-performance liquid chromatography diode-array detection (UPLC-DAD) and ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS), and the expressions of genes were detected by qRT-PCR. The two cultivars contained nine cyanidin anthocyanins and nine peonidin anthocyanins with an acylation modification. The acylation modification of anthocyanins in sweet potato leaves primarily included caffeoyl, p-coumaryl, feruloyl, and p-hydroxy benzoyl. We identified three anthocyanin compounds in sweet potato leaves for the first time: cyanidin 3-p-coumarylsophoroside-5-glucoside, peonidin 3-p-coumarylsophoroside-5-glucoside, and cyanidin 3-caffeoyl-p-coumarylsophoroside-5-glucoside. The anthocyanidin biosynthesis downstream structural genes DFR4, F3H1, anthocyanin synthase (ANS), and UDP-glucose flavonoid 3-O-glucosyltransferase (UFGT3), as well as the transcription factor MYB1, were found to be vital regulatory genes during the accumulation of anthocyanins in sweet potato leaves. The composition of anthocyanins (nine cyanidin-based anthocyanins and nine peonidin-based anthocyanins) in all sweet potato leaves were the same, but the quantity of anthocyanins in leaves of sweet potato varied by cultivar and differed from anthocyanin levels in the roots of sweet potatoes. The anthocyanidin biosynthesis structural genes and transcription factor together regulated and controlled the anthocyandin biosynthesis in sweet potato leaves.