Pulse crop seed coats are a sustainable source of antioxidant polyphenols, but are typically treated as low-value products, partly because some polyphenols reduce iron bioavailability in humans. This ...study correlates antioxidant/iron chelation capabilities of diverse seed coat types from five major pulse crops (common bean, lentil, pea, chickpea and faba bean) with polyphenol composition using mass spectrometry. Untargeted metabolomics was used to identify key differences and a hierarchical analysis revealed that common beans had the most diverse polyphenol profiles among these pulse crops. The highest antioxidant capacities were found in seed coats of black bean and all tannin lentils, followed by maple pea, however, tannin lentils showed much lower iron chelation among these seed coats. Thus, tannin lentils are more desirable sources as natural antioxidants in food applications, whereas black bean and maple pea are more suitable sources for industrial applications. Regardless of pulse crop, proanthocyanidins were primary contributors to antioxidant capacity, and to a lesser extent, anthocyanins and flavan-3-ols, whereas glycosylated flavonols contributed minimally. Higher iron chelation was primarily attributed to proanthocyanidin composition, and also myricetin 3-O-glucoside in black bean. Seed coats having proanthocyanidins that are primarily prodelphinidins show higher iron chelation compared with those containing procyanidins and/or propelargonidins.
Lentil seed coats are rich in antioxidant polyphenols that are important for plant defense and have potential as valorized byproducts. Although biochemical differences among lentil seed coat colors ...have been previously studied, differences among seed coat patterns remain largely unexplored. This study used mass spectrometry-based untargeted metabolomics to investigate polyphenol differences among lentil seed coat patterns to search for biochemical pathways potentially responsible for seed coat pattern differences. Comparing patterned with non-patterned green lentil seed coats, 28 significantly upregulated metabolites were found in patterned seed coats; 19 of them were identified as flavones. Flavones were virtually absent in non-patterned seed coats, thereby strongly suggesting a blockage in their flavone biosynthetic pathway. Although the black pattern is not readily discernible on black seed coats, many of the same flavones found in green marbled seed coats were also found in black seed coats, indicating that black seed coats likely have a marbled pattern.
Pulse crops are nutritious, but their seed coats are typically discarded, despite their high content of polyphenols. Polyphenol diversity among seed coats of five pulse crops was examined using a ...30‐min liquid chromatography‐mass spectrometry (LC‐MS) method. Notable differences within polyphenol classes were observed among crops and genotypes. Polyphenol profiling is the first step in understanding how pulse crop seed coats can be better utilised and also in ultimately determining which polyphenols and biochemical pathways are important for human health benefits.
Introduction
Pulse crops are nutritious and therefore widely grown. Pulse seed coats are typically discarded, despite their high content of polyphenols that are known for their antioxidant properties and health benefits. A better understanding of polyphenol diversity and biochemical pathways will ultimately provide insight into how polyphenols are linked to health benefits, which will help to better utilise these seed coats.
Objectives
To explore polyphenol profiles among seed coats of diverse genotypes of five pulse crops using a targeted liquid chromatography mass spectrometry (LC‐MS) method.
Methods
Four genotypes of each of common bean, chickpea, pea, lentil and faba bean seed coats were selected for analysis. Following extraction, polyphenols were quantified using LC‐MS.
Results
An LC‐MS method was developed to quantify 98 polyphenols from 13 different classes in 30 min. The low‐tannin seed coats had the lowest concentrations of all polyphenols. Chickpea and pea seed coats had the most similar polyphenolic profiles. The black common bean showed the most diverse seed coat polyphenol profile, including several anthocyanins not detected in any of the other seed coats.
Conclusion
The LC‐MS method reported herein was used to show polyphenol diversity within several polyphenol classes among the pulse crop seed coats. Detected in all seed coats, flavonols and hydroxybenzoic acids appear well‐conserved in the edible Fabaceae. The presence of anthocyanins, flavan‐3‐ols and proanthocyanins in the coloured seed coats suggests that unique divergent branches were introduced in the flavonoid biosynthetic pathway, possibly in response to environmental stressors.
•Higher antioxidant activity in normal-tannin lentil seed coats than low-tannin ones.•Higher water soluble phenolic levels in normal-tannin lentil seed coats.•Types of phenolic compounds in seed coat ...differed among lentil cultivars.•Kaempferol tetraglycoside was dominant in low-tannin seed coats.•Procyanidins, catechin-3-O-glucoside and kaempferol tetraglycoside in normal-tannin.
The seed coat is a major byproduct of lentil processing with potential as a sustainable source of antioxidant polyphenols. Profiles of water-soluble phenolic compounds and antioxidant activities of seven genotypes of lentil which includes both normal-tannin and low-tannin seed coats were investigated. Antioxidant activities were assessed using four antioxidant assays, and phenolic compounds were quantified using liquid chromatography mass spectrometry (LC-MS). Total phenolic content (TPC) varied significantly among genotypes and ranged between 1519 ± 140 and 6502 ± 154 μg/g. Thirty phenolic compounds were identified with kaempferol tetraglycoside, catechin-3-glucoside and procyanidins being the dominant compounds in normal-tannin seed coats. Kaempferol tetraglycoside predominated (80–90%) in low-tannin seed coats. Antioxidant activities strongly correlated with TPC (r > 0.93) with a 6–9 times higher activity in normal-tannin than that of low-tannin lentils. Without flavan-3-ols and procyanidins, low-tannin seed coat may not exert strong antioxidant potential, whereas normal-tannin seed coat contains water-extractable natural phenolic compounds with promising antioxidant potential.
Faba bean is a cool season grain legume that produces seeds with a high protein content. Seed coat tannins limit its use in food and feed. A low-tannin phenotype is controlled by either of two ...unlinked recessive genes zt1 and zt2. Liquid chromatography–mass spectrometry was used to characterize phenolic profiles of seed coat and flower tissue of three faba bean genotypes: CDC Snowdrop (zt1 gene), Disco/2 (zt2 gene), and ILB 938/2 (tannin-containing). For both tissues, clear differences in phenolic profiles of ILB 938/2 were observed in comparison to both low-tannin lines. Although seed coat phenolic profiles of zt1 and zt2 genotypes were similar, distinct differences were evident in flower tissue, suggesting that the gene action results in some different end products of the phenolic biosynthetic pathway. These distinctive compounds could be used as biochemical markers to distinguish between low-tannin phenotypes.
Introduction
Faba bean (
Vicia faba
L.) flowers are edible and used as garnishes because of their aroma, sweet flavor and attractive colors. Anthocyanins are the common plant pigments that give ...flowers their vivid colors, whereas non-anthocyanin flavonoids can serve as co-pigments that can modify the color intensity of flowers.
Objectives
To explore the polyphenol diversity and differences in standard and wing petals of faba bean flowers; and identify glycosylated flavonoids that contribute to flower color.
Methods
Flower standard and wing petals from 30 faba bean genotypes (eight color groups with a total of 60 samples) were used for polyphenol extraction. Samples were analyzed using a targeted method and a semi-untargeted analysis using liquid chromatography–high resolution mass spectrometry (LC–HRMS) combined with photodiode array (PDA) detection. Compound Discoverer software was used for polyphenol identification and multivariate analysis.
Results
The semi-untargeted analysis guided by the PDA detected 90 flavonoid metabolites present in faba bean flower petals. Ten anthocyanins largely influenced the flower colors, but other flavonoids (63 flavonols and 12 flavones) found with variable levels in different flower color groups appeared to also influence color, especially in mixed colors.
Conclusion
Analysis of the different colored faba bean flowers confirmed that the color variation between the flowers was mainly controlled by anthocyanins in brown, red and purple-red flowers. Of the other flavonoids, multiglycosylated kaempferols were abundant in white and brown flowers, monoglycosylated kaempferols were common in red and purple-red flowers, and quercetin and apigenin glycosides were abundant co-pigments in purple-red flowers.
The ability to tolerate low freezing temperatures is an important component of winter survival and persistence of red clover. Cold acclimation (CA) allows plants to acquire higher levels of freezing ...tolerance. However, the biochemical responses to cold and the importance of such changes for the plant to acquire adequate freezing tolerance have not been investigated in red clover of Nordic origin, which has a distinct genetic background. To shed light on this, we selected five freezing tolerant (FT) and five freezing susceptible (FS) accessions and studied the effect of CA on the contents of carbohydrates, amino acids, and phenolic compounds in the crowns. Among those compounds which increased during CA, FT accessions had higher contents of raffinose, pinitol, arginine, serine, alanine, valine, phenylalanine, and one phenolic compound (a pinocembrin hexoside derivative) than FS accessions, suggesting a role for these compounds in the freezing tolerance in the selected accessions. These findings, together with a description of the phenolic profile of red clover crowns, significantly add to the current knowledge of the biochemical changes during CA and their role in freezing tolerance in Nordic red clover.
ABSTRACT
Polyphenols play roles in plant defense mechanisms and are natural sources of antioxidants in food. A pea (Pisum sativum L.) recombinant inbred line (RIL) population (PR‐20) was developed ...from CDC Amarillo (white flower) and CDC Dakota (purple flower). Approximately half of the lines had white flowers and half had purple flowers, and these had two seed coat types (speckled and dun). The objective of this study was to use liquid chromatography coupled with mass spectrometry to compare polyphenolic profiles of seed components of four randomly selected PR‐20 lines from each of these three distinct groups to identify polyphenols that can be targeted in pea breeding. We quantified 30, 29, and 27 polyphenols in whole seeds, seed coats, and cotyledons, respectively. Except for gallic acid in whole seeds, no differences were observed between speckled and dun seed coats. Compared with white flower lines, 24, 23, and 12 compounds were at greater concentration in seed coats (3–6100 times), whole seeds (2–820 times) and cotyledons (2–110 times) of purple flower lines. Cotyledons of purple flower lines contained eight times more 3,4‐dihydroxybenzoic acid and 110 times more epigallocatechin than white flower lines. Ferulic acid, dihydrokaempferol, and kaempferol 3‐O‐glucoside were two to three times greater in cotyledons of white flower vs. purple flower lines. This study provides a basis for exploration of pea germplasm to identify accessions with high polyphenol content for breeding pea cultivars with improved health benefits in human diets.
•Green, fast and simple UPLC-ESI-MRM/MS method developed for the analysis of nine water-soluble vitamins in honey including two trace vitamins.•Twelve different honey samples from six different ...botanical origins were analyzed.•Greenness evaluation using analytical Eco-scale and GAPI shows the superiority of greenness of the proposed method over other reported methods.
Honey is one of the most commonly used natural products for nutritional and therapeutic purposes. Besides sugars, honey is characterized by complex chemical composition of minerals, polyphenols, water soluble vitamins, carotenoids and organic acids. In the present study, nine water soluble vitamins; C (L-ascorbic acid), B1 (thiamine), B2 (Riboflavin), B3H (nicotinic acid), B5 (D-pantothenic acid), B6 (pyridoxine), B7 (Biotin), B9 (Folic acid) and B12 (Cyanocobalamin) are determined simultaneously for the first time using an ultra-performance liquid chromatography-electrospray ionization multiple reaction monitoring/mass spectrometry (UPLC-ESI-MRM/MS) method coupled with a single simple sample preparation step. The simplicity and sensitivity of the proposed method permit the simultaneous determination of all nine water soluble vitamins including vitamins B7 and B12 that are present in trace amounts in various real honey samples. Complete chromatographic separation is achieved in 3 mins on a C18 column with a green mobile phase composed of a mixture of aqueous formic acid (0.1%, v/v) and methanol in gradient elution mode at a flow rate of 0.4 mLmin−1. The method is fully validated according to ICH guidelines. The greenness of our proposed method is assessed by comparing it to other proposed methods in terms of sample preparation, instrument energy consumption, consuming hazardous reagents and waste generation using Analytical Eco-scale and GAPI (Green Analytical Procedure Index). Results proved the superior greenness of our proposed method over the other reported ones. The proposed method is applied to twelve samples from six different monofloral honey types. Quantitation of the water-soluble vitamins content revealed concentrations ranging from 0.63 to 936.98 mgKg−1 in the analyzed honey samples with the successful determination of vitamins B7 and B12 in trace amounts. The highest vitamin content detected was for vitamin B3 in Jujube-tree honey while the lowest vitamin content was for vitamin B12 in Orange-tree honey. A marked relation was observed between the botanical origin and the vitamins’ concentrations of the studied honey samples. In addition, factors such as temperature, moisture, light and pH during storage greatly affect the vitamins content of honey. The developed method is intended to serve as a reliable, accurate, fast and green tool for the routine analysis of water-soluble vitamins in honey samples for quality control and research purposes.
PDF
