Diversity of phenolics including hydroxycinnamic acid amide derivatives, phenolic acids contribute to antioxidant properties of proso millet

Comprehensive evaluation on phenolic derivatives and antioxidant activities of diverse yellow maize varieties

The main phenolic derivatives and antioxidant capacity of ninety-three yellow maize varieties were investigated, together with their color parameters. Sixteen phenolics were identified in the free extract by UPLC-ESI-MS/MS, N', N″-diferuloyl putrescine and N', N″-dicoumaryl spermidine were the major phenolic derivatives. Fourteen phenolic compounds were found in the bound extract, with trans-p-coumaric acid, trans- and cis-ferulic acid being the predominant phenolic acids. The orange-yellow maize varieties presented the highest total phenolic content (TPC) and total flavonoid content (TFC), along with significantly higher antioxidant potential. Correlation analysis showed that b* value (corresponding to yellow degree) was positively correlated with the total carotenoid content (TCC), phenolic content, and antioxidant capacity (p < 0.05). Through Hierarchical Clustering Analysis (HCA), the 93 maize varieties could be divided into three categories according to b* value and antioxidant activity. The heatmap visualization further underscored the component differences across various varieties, unveiling the intricate phytochemical profiles of these maize varieties.

Effects of Sodium Selenite on Accumulations of Selenium and GABA, Phenolic Profiles, and Antioxidant Activity of Foxtail Millet During Germination

This study investigated the influence of soaking and spraying with a sodium selenite (Na2SeO3) solution on selenium accumulation, γ-aminobutyric acid (GABA) content, phenolic compositions, and the antioxidant activity of foxtail millet sprouts. The screening results showed that foxtail millet seeds soaked with 60 mg/L of Na2SeO3 solution and sprayed with 2 mg/L of Na2SeO3 solution were the appropriate concentrations for the germination process. Compared with the spraying method, a presoaking treatment presented far higher selenium content and significantly higher (p < 0.05) selenium enrichment rates in foxtail millet sprouts. The content of free and bound phenolics, as well as GABA, were significantly (p < 0.05) increased in foxtail millet sprouts through both soaking and spraying treatments. Correspondingly, most of the individual phenolic compounds were significantly (p < 0.05) increased, especially after germination for 3 days. Trans-ferulic acid and trans-p-coumaric acid were the predominate bound phenolic acids, feruloylquinic acid and 4-p-coumaroylquinic acid were the major free-form phenolic compounds, and N-feruloyl serotonin and N-(p-coumaroyl) serotonin were the new arising phenolic derivatives caused by germination. Both the soaking and spraying treatments induced the enrichment of these individual phenolic compositions, thus increasing the total phenolic content and in vitro antioxidant activity of foxtail millet sprouts. It was indicated that selenium-enriched germination treatment should be an effective method to produce functional selenium-enriched foxtail millet sprouts with more abundant GABA and polyphenols, thus enhancing the health benefits and added value of foxtail millet.

Harnessing the nutritional profile and health benefits of millets: a solution to global food security problems

India is dealing with both nutritional and agricultural issues. The maximum area of agricultural land with irrigation capabilities has been largely utilized, while the amount of dry land is expanding. The influence is distinct on farmer's livelihoods and earnings, which ultimately affects nutritional security. In order to attain nutritional security and the goal of SDG (Sustainable Development Goals), millets are sustainable solutions, with respect to high nutritional content, bioactive and medicinal properties, and climate resilience. The nutrient profile of millet includes 60%-70% carbohydrate content, 3.5%-5.2% fat, and 7.52%-12.1% protein sources. A wide spectrum of amino acids, including cysteine, isoleucine, arginine, leucine, tryptophan, lysine, histidine, methionine, tyrosine, phenylalanine, threonine, and valine are generally present in millets. Mineral content in millets includes calcium, phosphorus, potassium, sodium, and magnesium. Additionally, millets are an excellent source of bioactive molecules such as polyphenol, phenolic acid, flavonoids, active peptides, and soluble fiber, which have a wide range of therapeutic applications, including the prevention of free radical damage, diabetes, anti-microbial, anti- biofilm, and anti-cancer effects. This review will focus on the nutritional profile and health benefits of millet considering the present-day food security problems.

Optimization of Germination Conditions for Enriched γ-Aminobutyric Acid and Phenolic Compounds of Foxtail Millet Sprouts by Response Surface Methodology

The optimum germination conditions for foxtail millet sprouts enriched with γ-aminobutyric acid (GABA) and antioxidant polyphenols were investigated. From single-factor experimental results, both the GABA level and total phenolic content (TPC) were more significantly affected by soaking temperature and time, and concentration of sucrose culture solution. Response surface methodology (RSE) was used to optimize the germination conditions of foxtail millet sprouts, where the interaction between soaking temperature and sucrose concentration exhibited a significant (p < 0.05) effect on TPC, and the interaction between soaking time and sucrose concentration displayed a significant (p < 0.05) effect on GABA content. The optimal germination conditions for TPC and GABA enrichment of foxtail millet sprouts were soaking at 31 °C for 4.5 h and germinating at 35 °C with 4.5 g/L sucrose solution for 5 days. Under the optimized conditions, the TPC and GABA content of foxtail millet sprouts were 926.53 milligrams of ferulic acid equivalents per 100 g dry weight (mg FAE/100 g DW) and 259.13 mg/kg, separately, with less difference from the predicted values of 929.44 mg FAE/100 g DW and 263.60 mg/kg, respectively. Collectively, all the individual phenolic compounds increased significantly (p < 0.05) by optimization, except for cis-p-coumaric acid and cis-ferulic acid in bound. The results provide a practical technology for suitable germination conditions to improve the health components of foxtail millet sprouts and increase their added value.

Comparative study on the effects of grain blending on functional compound content and in vitro biological activity

In this study, changes in bioactive compound contents and the in vitro biological activity of mixed grains, including oats, sorghum, finger millet, adzuki bean, and proso millet, with eight different blending ratios were investigated. The total phenolic compounds and flavonoid contents ranged from 14.43-16.53 mg gallic acid equivalent/g extract and 1.22-5.37 mg catechin equivalent/g extract, respectively, depending on the blending ratio. The DI-8 blend (30% oats, 30% sorghum, 15% finger millet, 15% adzuki bean, and 10% proso millet) exhibited relatively higher antioxidant and anti-diabetic effects than other blending samples. The levels of twelve amino acids and eight organic acids in the grain mixes were measured. Among the twenty metabolites, malonic acid, asparagine, oxalic acid, tartaric acid, and proline were identified as key metabolites across the blending samples. Moreover, the levels of lactic acid, oxalic acid, and malonic acid, which are positively correlated with α-glucosidase inhibition activity, were considerably higher in the DI-blending samples. The results of this study suggest that the DI-8 blend could be used as a functional ingredient as it has several bioactive compounds and biological activities, including anti-diabetic activity.

Advances in the novel and green-assisted techniques for extraction of bioactive compounds from millets: A comprehensive review

Millets are rich in nutritional and bioactive compounds, including polyphenols and flavonoids, and have the potential to combat malnutrition and various diseases. However, extracting these bioactive compounds can be challenging, as conventional methods are energy-intensive and can lead to thermal degradation. Green-assisted techniques have emerged as promising methods for sustainable and efficient extraction. This review explores recent trends in employing green-assisted techniques for extracting bioactive compounds from millets, and potential applications in the food and pharmaceutical industries. The objective is to evaluate and comprehend the parameters involved in different extraction methods, including energy efficiency, extraction yield, and the preservation of compound quality. The potential synergies achieved by integrating multiple extraction methods, and optimizing extraction efficiency for millet applications are also discussed. Among several, Ultrasound and Microwave-assisted extraction stand out for their rapidity, although there is a need for further research in the context of minor millets. Enzyme-assisted extraction, with its low energy input and ability to handle complex matrices, holds significant potential. Pulsed electric field-assisted extraction, despite being a non-thermal approach, requires further optimization for millet-specific applications, are few highlights. The review emphasizes the importance of considering specific compound characteristics, extraction efficiency, purity requirements, and operational costs when selecting an ideal technique. Ongoing research aims to optimize novel extraction processes for millets and their byproducts, offering promising applications in the development of millet-based nutraceutical food products. Therefore, the current study benefits researchers and industries to advance extraction research and develop efficient, sustainable, and scalable techniques to extract bioactive compounds from millets.

Dynamic changes in microbial communities and flavor during different fermentation stages of proso millet Baijiu, a new product from Shanxi light-flavored Baijiu

Introduction

Proso millet, a high-quality fermentation material used for Chinese yellow wine production, can produce special flavored substances; however, its role in improving the flavor and altering microbial communities of light-flavored Baijiu during fermentation remain unknown. Thus, we aimed to investigate the effect of proso millet on improving the flavor of light-flavored Baijiu and altering microbial communities during different fermentation stages.

Methods

The dynamic changes in the microbial communities and flavor of proso millet (50%) + sorghum (50%) mixed fermentation samples were analyzed through intermittent sampling on days 7, 14, 21, and 28 of the fermentation process. Microbial high-throughput sequencing and the analysis of flavor characteristics were conducted through 16S DNA/ ITS amplicon sequencing and gas chromatography (multi-capillary column)-ion mobility spectrometry, respectively.

Results

Proso millet significantly changed the core flavor compound composition of traditional light-flavored Baijiu from ethyl acetate, ethyl hexanoate, ethyl hexanoate dimer, ethyl butanoate, ethyl lactate, and butyl acetate to oct-2-ene, 2-butanol, propyl propanoate, 2-pentenal, and 4-methylpentanal. The amplicon sequencing analysis revealed that the alpha diversity parameters of bacterial and fungal communities, including the Chao1, Pielou_e, Shannon, and Simpson indices, for proso millet-sorghum mixed fermentation samples were significantly higher than those for sorghum fermentation samples (p < 0.05). Of the 40 most significant microbial genera in two treatments, proso millet significantly increased the abundance of 12 bacterial and 18 fungal genera. Among the 40 most significant bacterial and fungal species, 23 bacterial species belonged to the Lactobacillus genus, whereas the 30 primary fungal species belonged to 28 different genera. The analysis of the relationship between microbial changes and the main flavor compounds of light-flavored Baijiu showed that bacteria from the Weissella, Acinetobacter, Bacteroides, Psychrobacter, Pseudarthrobacter, Lactococcus, Chloroplast, Saccharopolyspora, Psychrobacter, Saccharopolyspora, Pseudonocardiaceae, Bacteroides genera and fungi from the Thermoascus, Aspergillus, Pichia, Rhizomucor, Papiliotrema, Hyphopichia, and Mucor genera significantly inhibited the synthesis of ethyl hexanoate, ethyl butanoate, ethyl lactate ethyl lactate, and butyl acetate but increased the synthesis of ethyl acetate (p < 0.05). Moreover, these microbes exhibited a significantly greater abundance in proso millet-sorghum mixed fermentation samples than in sorghum samples. The synthesis of special flavored compounds in proso millet Baijiu was significantly positively correlated with the presence of fungi from the Rhizopus, Papiliotrema, Wickerhamomyces, Aspergillus, and Thermoascus genera but negative correlated with the presence of bacteria from the Weissella, Acinetobacter, Psychrobacter, Pseudarthrobacter, Bacteroides, and Saccharopolyspora genera. Regarding ethanol content, the low alcohol content of Fenjiu may be due to the significantly high abundance of fungi from the Psathyrella genus and bacteria from the Staphylococcus, Kroppenstedtia, Brevibacterium, and Acetobacter genera during fermentation. In summary, proso millet significantly altered the flavor of light-flavored Baijiu by inducing the formation of a special microbial community; however, it did not increase alcohol concentration.

Discussion

This study lays the foundation for future research on Baijiu fermentation. Additionally, the study findings may help improve the production efficiency and elevate the quality and flavor of the final product.

Noncovalent Interaction of Lactoferrin with Epicatechin and Epigallocatechin: Focus on Fluorescence Quenching and Antioxidant Properties

Lactoferrin (LF) from bovine milk possesses antioxidant activity, immune regulatory and other biological activities. However, the effects of epicatechin (EC) and epigallocatechin (EGC) interacting with LF on the antioxidant activity of LF have not been investigated. Therefore, this study aimed to explore their interaction mechanism and the antioxidant activity of LF. UV spectra revealed that EGC (100 μM) induced a higher blue shift of LF at the maximum absorption wavelength than that of EC (100 μM). Fluorescence spectra results suggested that LF fluorescence was quenched by EC and EGC in the static type, which changed the polarity of the microenvironment around LF. The quenching constants Ksv (5.91 × 103-9.20 × 103) of EC-LF complexes at different temperatures were all higher than that (1.35 × 103-1.75 × 103) of the EGC-LF complex. EC could bind to LF via hydrophobic interactions while hydrogen bonding and van der Waals forces drove the binding of EGC to LF. Both the EC-LF complex and EGC-LF complex could bind to LF with one site. EGC formed more hydrogen bonds with LF than that of EC. The antioxidant activity of LF was increased by the high addition level of EC and EGC. These findings would provide more references for developing LF-catechin complexes as functional antioxidants.

Optimization of Ultrasound-Assisted Extraction and Characterization of the Phenolic Compounds in Rose Distillation Side Streams Using Spectrophotometric Assays and High-Throughput Analytical Techniques

Lately, the essential oils industry has been one of the most expanding markets globally. However, the byproducts generated after the distillation of aromatic plants and their transformation to novel high-added value products consist of a major up-to-date challenge. Thus, the scope of the current study is the optimization of ultrasound-assisted extraction (UAE) for the recovery of phenolic compounds from rose (Rosa damascena) post-distillation side streams using Box-Behnken design. In particular, the highest total phenolic content (TPC) was achieved at 71% v/v ethanol-water solution, at 25 min, 40 mL/g dry sample and 53% ultrasound power, while ethanol content and extraction time were the most crucial factors (p-value ≤ 0.05) for UAE. Both solid (RSB) and liquid (LSB) rose side streams exhibited significant antiradical and antioxidant activities. The interpretation of attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectra confirmed the presence of compounds with properties such as phenolic compounds, phenolic amide derivatives, and alcohols in the extracts. Moreover, the flavonoids naringenin, quercetin, and kaempferol were the major phenolic compounds, identified in the extracts by liquid chromatography-tandem mass spectrometry analysis (LC-MS/MS), followed by gallic, protocatechuic, p-hydroxybenzoic, and rosmarinic acids. Furthermore, the LC-MS/MS results pinpointed the effect of factors other than the extraction conditions (harvesting parameters, climatic conditions, plant growth stage, etc.) on the phenolic fingerprint of RSB extracts. Therefore, RSB extracts emerge as a promising alternative antioxidant agent in food products.

Synthesis, Crystal Structure, Spectral Characterization and Antifungal Activity of Novel Phenolic Acid Triazole Derivatives

At present, phenolic acid derivatives and triazole derivatives have a good antifungal effect, which has attracted widespread attention. A series of novel phenolic acid triazole derivatives were synthesized, and their structures were characterized by IR, MS, NMR, and X-ray crystal diffraction. Compound methyl 4-(2-bromoethoxy)benzoate, methyl 4-(2-(1H-1,2,4-triazol-1-yl) ethoxy)benzoate, 4-(2-(1H-1,2,4-triazol-1-yl)ethoxy)benzoic acid and 4-(2-(1H-1,2,4-triazol-1-yl) ethoxy)-3-methoxybenzoic acid crystallize in the monoclinic system with space group P21/n, the monoclinic system with space group P21, the monoclinic system with space group P21 and the orthorhombic system with space group Pca21, respectively. At a concentration of 100 μg/mL and 200 μg/mL, the antifungal activity against seven plant pathogen fungi was determined. Compound methyl 4-(2-bromoethoxy)benzoate has the best inhibitory effect on Rhizoctonia solani AG1, and the inhibitory rate reached 88.6% at 200 μg/mL. The inhibitory rates of compound methyl 4-(2-(1H-1,2,4-triazol-1-yl) ethoxy)benzoate against Fusarium moniliforme and Sphaeropsis sapinea at a concentration of 200 μg/mL were 76.1% and 75.4%, respectively, which were better than that of carbendazim.

Proso Millet (Panicum miliaceum L.) as Alternative Source of Starch and Phenolic Compounds: A Study on Twenty-Five Worldwide Accessions

Proso millet has been proposed as an effective anti-diabetic food thanks to the combined action of polyphenols and starch. This study aimed to characterize the chemical composition of twenty-five accessions, in order to enhance this cereal as an alternative to available starch for food applications or to propose new food ingredients with health benefits. Proso millet contained a high percentage of starch, reaching values of 58.51%. The amylose content showed high variability, with values ranging from 1.36 to 42.70%, and significantly higher values were recorded for the white accessions than for the colored ones. High-resistant starch content (13.41-26.07%) was also found. The HPLC-MS analysis showed the same phenolic pattern in all the samples. Cinnamic acids are the most abundant compounds and significant differences in their total content were found (0.69 to 1.35 mg/g DW), while flavonoids were only detected in trace amounts. Statistical results showed significantly higher antiradical activity in the colored accessions than in the white ones.

Modification on phenolic profiles and enhancement of antioxidant activity of proso millets during germination

Changes in phenolic profiles and antioxidant activity of three varieties of proso millet during germination were investigated. Total phenolic content (TPC) and total flavonoid content (TFC) increased significantly with prolongation in germination period. After germination for 6 days, TPC of the free and bound fractions increased 6.30-8.66-fold and 77.65-116.18%, respectively. The free and bound phenolic compounds identified by UPLC-MS/MS, displayed significant variations. Feruloylquinic acid and N,N'-bis-(p-coumaroyl)-putrescine biosynthesized during germination, are reported for the first time in proso millets. Other phenolics including trans- and cis-ferulic, trans-p-coumaric, vanillic acid and ferulic acid dimers (DFAs) were increased significantly along with a new DFA (8,5'-DFA) seemingly produced during germination. The germinated proso milllets displayed superior antioxidant activity than the corresponding ungerminated samples indicating that germination could be one applicable method for improving phenolic profiles and antioxidant capacity of proso millets. Thus germinated proso millet could be exploited as a functional ingredient in several products.

Implication of solvent polarities on browntop millet (Urochloa ramosa) phenolic antioxidants and their ability to protect oxidative DNA damage and inhibit α-amylase and α-glucosidase enzymes

Phenolics of browntop millet extracted in solvents with varying polarities [water, methanol, acetone (80%), ethanol (70%)] were comparatively assessed for their phenolic profiles, antioxidant activities, DNA damage protection and enzyme inhibitory properties. Results indicated that acetone (80%) and ethanol (70%) were most effective in extracting millet phenolics than other solvents. Gallic, caffeic and ferulic acids were the major phenolic acids, myricetin and kaempferol were the most abundant flavonoids detected in all the extracts of browntop millet. Phenolics extracted in 80% acetone and 70% ethanol offered noticeable contributions toward several antioxidant mechanisms and prevented the oxidative DNA damage than water and methanol extracts. All the millet extracts exhibited potent inhibition towards α-glucosidase than α-amylase activities. These results suggest that the solvents and their polarities impacted the extraction and bioactivities of millet phenolics and provided useful information for the effective utilization of browntop millet as a functional food ingredient to manage hyperglycemia.

From Foxtail Millet Husk (Waste) to Bioactive Phenolic Extracts Using Deep Eutectic Solvent Extraction and Evaluation of Antioxidant, Acetylcholinesterase, and α-Glucosidase Inhibitory Activities

Foxtail millet husk (FMH) is generally removed and discarded during the first step of millet processing. This study aimed to optimize a method using deep eutectic solvents (DESs) combined with ultrasonic-assisted extraction (UAE) to extract phenols from FMH and to identify the phenolic compositions and evaluate the biological activities. The optimized DES comprised L-lactic acid and glycol with a 1:2 molar ratio by taking the total flavonoid content (TFC) and total phenolic content (TPC) as targets. The extraction parameters were optimized to maximize TFC and TPC, using the following settings: liquid-to-solid ratio of 25 mL/g, DES with water content of 15%, extraction time of 41 min and temperature of 51 °C, and ultrasonic power at 304 W. The optimized UAE-DES, which produced significantly higher TPC, TFC, antioxidant activity, α-glucosidase, and acetylcholinesterase inhibitory activities compared to conventional solvent extraction. Through UPLC–MS, 12 phenolic compounds were identified, with 1-O-p-coumaroylglycerol, apigenin-C-pentosyl-C-hexoside, and 1-O-feruloyl-3-O-p-coumaroylglycerol being the main phenolic components. 1-O-feruloyl-3-O-p-coumaroylglycerol and 3,7-dimethylquercetin were identified first in foxtail millet. Our results indicated that FMH could be exploited by UAE-DES extraction as a useful source of naturally derived antioxidants, along with acetylcholinesterase and α-glucosidase inhibitory activities.

Polyphenol-Dietary Fiber Conjugates from Fruits and Vegetables: Nature and Biological Fate in a Food and Nutrition Perspective

In the past few years, numerous studies have investigated the correlation between polyphenol intake and the prevention of several chronic diseases. Research regarding the global biological fate and bioactivity has been directed to extractable polyphenols that can be found in aqueous-organic extracts, obtained from plant-derived foods. Nevertheless, significant amounts of non-extractable polyphenols, closely associated with the plant cell wall matrix (namely with dietary fibers), are also delivered during digestion, although they are ignored in biological, nutritional, and epidemiological studies. These conjugates have gained the spotlight because they may exert their bioactivities for much longer than extractable polyphenols. Additionally, from a technological food perspective, polyphenols combined with dietary fibers have become increasingly interesting as they could be useful for the food industry to enhance technological functionalities. Non-extractable polyphenols include low molecular weight compounds such as phenolic acids and high molecular weight polymeric compounds such as proanthocyanidins and hydrolysable tannins. Studies concerning these conjugates are scarce, and usually refer to the compositional analysis of individual components rather than to the whole fraction. In this context, the knowledge and exploitation of non-extractable polyphenol-dietary fiber conjugates will be the focus of this review, aiming to access their potential nutritional and biological effect, together with their functional properties.

Therapeutic Potential of Phenolic Compounds in Medicinal Plants-Natural Health Products for Human Health

Phenolic compounds and flavonoids are potential substitutes for bioactive agents in pharmaceutical and medicinal sections to promote human health and prevent and cure different diseases. The most common flavonoids found in nature are anthocyanins, flavones, flavanones, flavonols, flavanonols, isoflavones, and other sub-classes. The impacts of plant flavonoids and other phenolics on human health promoting and diseases curing and preventing are antioxidant effects, antibacterial impacts, cardioprotective effects, anticancer impacts, immune system promoting, anti-inflammatory effects, and skin protective effects from UV radiation. This work aims to provide an overview of phenolic compounds and flavonoids as potential and important sources of pharmaceutical and medical application according to recently published studies, as well as some interesting directions for future research. The keyword searches for flavonoids, phenolics, isoflavones, tannins, coumarins, lignans, quinones, xanthones, curcuminoids, stilbenes, cucurmin, phenylethanoids, and secoiridoids medicinal plant were performed by using Web of Science, Scopus, Google scholar, and PubMed. Phenolic acids contain a carboxylic acid group in addition to the basic phenolic structure and are mainly divided into hydroxybenzoic and hydroxycinnamic acids. Hydroxybenzoic acids are based on a C6-C1 skeleton and are often found bound to small organic acids, glycosyl moieties, or cell structural components. Common hydroxybenzoic acids include gallic, syringic, protocatechuic, p-hydroxybenzoic, vanillic, gentistic, and salicylic acids. Hydroxycinnamic acids are based on a C6-C3 skeleton and are also often bound to other molecules such as quinic acid and glucose. The main hydroxycinnamic acids are caffeic, p-coumaric, ferulic, and sinapic acids.

Health-Promoting Potential of Millet: A Review

Being a key source of animal food, millet production has been sharply increasing over the last few years in order to cope with the dietary requirements of the ever-increasing world population. It is a splendid source of essential nutrients such as protein, carbohydrates, fat, minerals, vitamins, and also some other bioactive compounds that eventually help through multiple biological activities, including antioxidant, anti-hyperglycemic, anti-cholesterol, anti-hypertensive, anthropometric effects and regulation of gut microbiota composition. These bioactive compounds, nutrients, and functions of cereal grains can be affected by processing techniques such as decortication, soaking, malting, milling, fermentation, etc. This study discusses the nutritional and functional properties of millet-incorporated foods and their impact on health, based on around 150 articles between 2015 and 2022 from the Web of Science, Google Scholar, Food and Agriculture Organization of the United Nations (FAO), Breeding Bid Survey (BBS), and FoodData Central (USDA) databases. Analyzing literature reviews, it is evident that the incorporation of millet and its constituents into foodstuffs could be useful against undernourishment and several other health diseases. Additionally, this review provides crucial information about the beneficial features of millet, which can serve as a benchmark of guidelines for industry, consumers, researchers, and nutritionists.

Integrated metabolite analysis and health-relevant in vitro functionality of white, red, and orange maize (Zea mays L.) from the Peruvian Andean race Cabanita at different maturity stages

The high maize (Zea mays L.) diversity in Peru has been recognized worldwide, but the investigation focused on its integral health-relevant and bioactive characterization is limited. Therefore, this research aimed at studying the variability of the primary and the secondary (free and dietary fiber-bound phenolic, and carotenoid compounds) metabolites of three maize types (white, red, and orange) from the Peruvian Andean race Cabanita at different maturity stages (milk-S1, dough-S2, and mature-S3) using targeted and untargeted methods. In addition, their antioxidant potential, and α-amylase and α-glucosidase inhibitory activities relevant for hyperglycemia management were investigated using in vitro models. Results revealed a high effect of the maize type and the maturity stage. All maize types had hydroxybenzoic and hydroxycinnamic acids in their free phenolic fractions, whereas major bound phenolic compounds were ferulic acid, ferulic acid derivatives, and p-coumaric acid. Flavonoids such as luteolin derivatives and anthocyanins were specific in the orange and red maize, respectively. The orange and red groups showed higher phenolic ranges (free + bound) (223.9-274.4 mg/100 g DW, 193.4- 229.8 mg/100 g DW for the orange and red maize, respectively) than the white maize (162.2-225.0 mg/100 g DW). Xanthophylls (lutein, zeaxanthin, neoxanthin, and a lutein isomer) were detected in all maize types. However, the orange maize showed the highest total carotenoid contents (3.19-5.87 μg/g DW). Most phenolic and carotenoid compounds decreased with kernel maturity in all cases. In relation to the primary metabolites, all maize types had similar fatty acid contents (linoleic acid > oleic acid > palmitic acid > α-linolenic acid > stearic acid) which increased with kernel development. Simple sugars, alcohols, amino acids, free fatty acids, organic acids, amines, and phytosterols declined along with grain maturity and were overall more abundant in white maize at S1. The in vitro functionality was similar among Cabanita maize types, but it decreased with the grain development, and showed a high correlation with the hydrophilic free phenolic fraction. Current results suggest that the nutraceutical characteristics of orange and white Cabanita maize are better at S1 and S2 stages while the red maize would be more beneficial at S3.

Diversity of the Peruvian Andean maize (Zea mays L.) race Cabanita: Polyphenols, carotenoids, in vitro antioxidant capacity, and physical characteristics

The high diversity of the Peruvian Andean maize (Zea mays L.) represents a biological and genetic heritage relevant for food security, but few studies are targeted toward its characterization and consequent valorization and preservation. The objective of this study was to evaluate the potential of the Peruvian Andean maize race Cabanita with respect to its bioactive profiles (free and bound phenolic and carotenoid composition), physical characteristics, and in vitro antioxidant properties. Maize landraces with variable kernel pigmentation were collected from two provinces (Caylloma and Castilla) within the Arequipa region (among ten Andean sites) and the phytochemical profile was evaluated by Ultra High-Performance Liquid Chromatography with diode array detector (UHPLC-DAD). All maize samples were important sources of phenolic compounds mainly soluble p-coumaric and ferulic acid derivatives whereas anthocyanins were only detected in maize with partially red pigmented kernels. Major phenolic compounds in the bound phenolic fractions were ferulic acid and its derivatives along with p-coumaric acid. Carotenoid compounds including xanthophylls such as lutein, lutein isomers, and zeaxanthin were only detected in orange and white-yellow pigmented maize and are reported for the first time in Peruvian landraces. The multivariate analysis using Principal Components Analysis (PCA) revealed low variability of all data which may indicate a level of similarity among maize samples based on evaluated variables. However, maize grown in Caylloma province showed more homogeneous physical characteristics and higher yield, whereas higher phenolic contents and antioxidant capacity were observed in maize from Castilla. Samples CAY (yellow-pigmented kernel, Castilla) and COM (orange-pigmented kernel, Caylloma) had the highest total phenolic (246.7 mg/100 g dried weight basis, DW) and carotenoid (1.95 μg/g DW) contents among all samples. The variable Andean environmental conditions along with differences in farming practices may play a role and should be confirmed with further studies. Current results provide the metabolomic basis for future research using integrated omics platforms targeted toward the complete characterization of the ethnic-relevant maize race Cabanita.

Genome-Wide Identification of Genes Related to Biosynthesis of Phenolic Acid Derivatives in Bletilla striata at Different Suspension Culture Stages

To screen the genes regulating the biosynthesis of phenolic acid derivatives from the genome of Bletilla striata, we designed a suspension culture system to sample the cells for the following experiments. The contents of four phenolic acid derivatives were determined by high-performance liquid chromatography, and several full-length transcriptome sequencings of RNA samples at 10 time points were performed for bioinformatics analysis. The correlation analysis was used to identify and verify the key DEGs involved in the biosynthesis of the four phenolic acid derivatives. The results showed that the contents of p-hydroxybenzylalcohol (HBA), Dactylorhin A, Militarine, and Coelonin peaked at 33 days postinoculation (Dpi), 18 Dpi, 39 Dpi, and 39 Dpi of the culture system, respectively. Based on transcriptome data, 80 DEGs involved in the biosynthesis of phenolic acid derivatives were obtained. The KEGG pathway enrichment analysis classified them mostly into five metabolic pathways: phenylpropane biosynthesis, starch and sucrose metabolic, cyanoamino acid metabolism, gluconeogenesis and glycolysis, and phenylalanine metabolism. qPCR analysis revealed that the relative gene expression levels were consistent with the overall trend of transcriptome sequencing results. Among them, 14, 18, 23, and 41 unigenes were found to be involved in the synthesis of HBA, Dactylorhin A, Coelonin, and Militarine, respectively. These unigenes laid a solid foundation for elucidating the biosynthesis mechanism of phenolic acid derivatives in suspension cells of B. striata.