Volatile compounds of raw and cooked green kohlrabi were investigated using a sensomics approach. A total of 55 odor-active compounds were detected and identified in raw and cooked green kohlrabi ...using GC-O. Twenty-eight odor-active compounds with high flavor dilution (FD) factors ranging from 64 to 1024 were quantitated, and odor activity values (OAVs) were determined. Eight compounds showed high OAVs in raw and cooked kohlrabi: five sulfur compounds (dimethyl trisulfide, methyl 2-methyl-3-furyl disulfide, and three isothiocyanates (1-isothiocyanato-3-(methylsulfanyl)propane, benzyl isothiocyanate, and 1-isothiocyanato-4-(methylsulfanyl)butane)), two lipid oxidation products (1-octen-3-one and trans-4,5-epoxy-(2E)-dec-2-enal), and 2-isopropyl-3-methoxypyrazine. Among these, the sulfur compounds contributed most to the overall smell of the raw and cooked vegetables. The quantitation analysis indicates that the eight odorants are the backbone compounds for raw and cooked kohlrabi. The OAVs for the backbone compounds and also for minor odorants are clearly higher in raw kohlrabi than in the cooked one. Differences can be explained by the influence of the cooking process.
Kohlrabi (Brassica oleracea var. gongylodes L.) is an important dietary vegetable cultivated and consumed widely for the round swollen stem. Purple kohlrabi shows abundant anthocyanin accumulation in ...the leaf and swollen stem. Here, different kinds of anthocyanins were separated and identified from the purple kohlrabi cultivar (Kolibri) by high-performance liquid chromatography–electrospray ionization tandem mass spectrometry. In order to study the molecular mechanism of anthocyanin biosynthesis in purple kohlrabi, the expression of anthocyanin biosynthetic genes and regulatory genes in purple kohlrabi and a green cultivar (Winner) was examined by quantitative PCR. In comparison with the colorless parts in the two cultivars, most of the anthocyanin biosynthetic genes and two transcription factors were drastically upregulated in the purple tissues. To study the effects of light shed on the anthocyanin accumulation of kohlrabi, total anthocyanin contents and transcripts of associated genes were analyzed in sprouts of both cultivars grown under light and dark conditions.
: Biofortification of vegetables with selenium (Se) greatly depends on species tolerance to Se supply. Due to the scant information regarding kohlrabi Se biofortification, the aim of the present work ...was the evaluation of foliar sodium selenate application on yield and biochemical characteristics of three kohlrabi cultivars.
: A two years field experiment was conducted in Moscow region (Russia) on 3 kohlrabi cultivars using foliar biofortification with Na
Se0
solutions (50, 75 and 100 mg/L) and subsequent biochemical analysis of roots, stems and leaves.
: Out of the three concentrations tested (50, 75 and 100 mg/L) plus an untreated control, the Se 75 dose demonstrated the strongest growth stimulation effect resulting in the increase of stem weight (by 1.35-1.61 times), yield (1.37-1.66 times), monosaccharide (1.59-2.24 times), ascorbic acid (1.54-2.01 times) and total phenolic levels (by 1.23-1.37 times), compared to the untreated control. The biofortification values varied from 69.4 (White Vienna 1390) to 59.9 (Dobrynya F
hybrid) and 43.6 (Sonata F
hybrid) under the Se dose of 100 mg/L. The maximum Se content in kohlrabi stems reached 4.40 mg/kg d.w. for Sonata F
, 3.53 mg/kg d.w. for Dobrynya F
hybrids and 5.20 mg/kg d.w. for cultivar White Vienna 1390. Significant correlations were revealed between Se and total phenolics (0.720;
< 0.002), ascorbic acid (0.842;
< 0.001), monosaccharides (0.898;
< 0.001) and total sugar (0.764;
< 0.001). No significant changes in nitrate levels and dry matter content were recorded as the result of Se supply.
: The outcomes of the present research demonstrated the high benefits of Se application in improving kohlrabi yield and nutritional quality.
This study examines the effect of irradiance level produced by solid-state light-emitting diodes (LEDs) on the growth, nutritional quality and antioxidant properties of Brassicaceae family ...microgreens. Kohlrabi (Brassica oleracea var. gongylodes, ‘Delicacy Purple’) mustard (Brassica juncea L., ‘Red Lion’), red pak choi (Brassica rapa var. chinensis, ‘Rubi F₁’) and tatsoi (Brassica rapa var. rosularis) were grown using peat substrate in controlled-environment chambers until harvest time (10 days, 21/17°C, 16 h). A system of five lighting modules with 455, 638, 665 and 731 nm LEDs at a total photosynthetic photon flux densities (PPFD) of 545, 440, 330, 220 and 110 µmol m⁻²s⁻¹ respectively were used. Insufficient levels of photosynthetically active photon flux (110 µmol m⁻² s⁻¹) suppressed normal growth and diminished the nutritional value of the Brassica microgreens studied. In general, the most suitable conditions for growth and nutritional quality of the microgreens was 330–440 µmol m⁻² s⁻¹ irradiation, which resulted in a larger leaf surface area, lower content of nitrates and higher total anthocyanins, total phenols and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free-radical scavenging capacity. High light levels (545 µmol m⁻² s⁻¹), which was expected to induce mild photostress, had no significant positive impact for most of investigated parameters.
We profiled and quantified glucosinolates, anthocyanins, carotenoids, and other secondary metabolites in the skin and flesh of pale green and purple kohlrabis. Analysis of these distinct kohlrabis ...revealed the presence of 8 glucosinolates, 12 anthocyanins, 2 carotenoids, and 7 phenylpropanoids. Glucosinolate contents varied among the different parts and types of kohlrabi. Glucoerucin contents were 4-fold higher in the flesh of purple kohlrabi than those in the skin. Among the 12 anthocyanins, cyanidin 3-(feruloyl)(sinapoyl) diglucoside-5-glucoside levels were the highest. Carotenoid levels were much higher in the skins than the flesh of both types of kohlrabi. The levels of most phenylpropanoids were higher in purple kohlrabi than in pale green ones. trans-Cinnamic acid content was 12.7-fold higher in the flesh of purple kohlrabi than that in the pale green ones. Thus, the amounts of glucosinolates, anthocyanins, carotenoids, and phenylpropanoids varied widely, and the variations in these compounds between the two types of kohlrabi were significant.
Brassica oleracea var. gongylodes (red kohlrabi) is a biennial herbaceous vegetable whose edible bulbotuber-like stem and leaves are consumed globally. Sliced red kohlrabi tubers were extracted using ...methanol and the concentrated extract was partitioned successively with dichloromethane (CH2Cl2), ethyl acetate (EtOAc), n-butanol (n-BuOH) and water (H2O). Repeated column chromatography of EtOAc fraction through silica, sephadex LH-20 and RP-18 gel led to isolation of eleven compounds of which compound 1 was a new glycosylated indole alkaloid derivative, 1-methoxyindole 3-carboxylic acid 6-O-β-D-glucopyranoside. Others were known compounds namely, β-sitosterol glucoside (4), 5-hydroxymethyl-2-furaldehyde (5), methyl-1-thio-β-D-glucopyranosyl disulfide (6), 5-hydroxy-2-pyridinemethanol (7), (3S,4R)-2-deoxyribonolactone (8), n-butyl-β-D-fructopyranoside (9), uridine (10) and three fructose derivatives, D-tagatose (11), β-D-fructofuranose (12) and β-D-fructopyranose (13). Similarly, isolation from CH2Cl2 fraction gave two known indole alkaloids, indole 3-acetonitrile (2) and N-methoxyindole 3-acetonitrile (3). The structure elucidation and identification of these compounds were conducted with the help of 13C and 1H NMR, HMBC, HMQC, EIMS, HR-ESIMS and IR spectroscopic data, and TLC plate spots visualization. Compounds 2, 3, 4, 5, 6, 7, 8 and 9 are noted to occur in kohlrabi for the first time. Different bioactivities of these isolated compounds have been reported in literature. KCI Citation Count: 0
In this study, a 8.5-kDa antifungal peptide designated as BGAP was purified from the crude extract of the seeds of
var.
by employing a protocol that comprised cation exchange chromatography on ...SP-Sepharose, cation exchange chromatography on Mono S and gel filtration chromatography on Superdex peptide. BGAP showed the highest amino acid sequence similarity to defensin peptides by mass spectrometric analysis. BGAP showed a broad spectrum of antifungal activity with a half maximal inhibitory concentration at 17.33 μg/mL, 12.37 μg/mL, 16.81 μg/mL, and 5.60 μg/mL toward
,
,
and
, respectively. The antifungal activity of BGAP remained stable (i) after heat treatment at 40-100 °C for 15 min; (ii) after exposure to solutions of pH 1-3 and 11-13 for 15 min; (iii) after incubation with solutions containing K⁺, Ca
, Mg
, Mn
or Fe
ions at the concentrations of 20-150 mmol/L for 2 h; and (iv) following treatment with 10% methyl alcohol, 10% ethanol, 10% isopropanol or 10% chloroform for 2 h. Fluorescence staining experiments showed that BGAP brought about an increase in cell membrane permeability, a rise in reactive oxygen species production, a decrease in mitochondrial membrane potential, and an accumulation of chitin at the hyphal tips of
.
The vegetable and cereal sprouts’ consumption is a modern, pleasant and lowcost way to ensure a healthy diet. The kohlrabi sprouts are particularly rich in antioxidants, especially in polyphenolic ...compounds. The present paper analyses the antioxidant properties reflected by total polyphenolics and radical scavenging capacity of edible kohlrabi sprouts at different maturity stages (5, 7 and 9 days old), in the purpose to suggest the optimal harvest time to produce sprouts with better health-promoting content. The obtained results recommend the harvest of 5-days sprouts, if the producer is interested in a high content of total polyphenolics and increased soluble dry matter. In the case that a product with higher radical scavenging capacity, no matter the nature of contained antioxidants, is required, then the harvest of kohlrabi at the stage of 7-days old sprouts is recommended.
Kohlrabi (Brassica oleracea var. gongylodes) is a vegetable cultivated for its edible stem tuber. Although valued for its nutritional properties and tolerance to abiotic stress, kohlrabi is one of ...the least studied brassicas. In this review, we summarize the results of our decade-long research on in vitro morphogenesis of kohlrabi, starting from 2013. Protocols for efficient in vitro regeneration with minimal requirements for external application of plant growth regulators (PGRs) have been developed, both by somatic embryogenesis (SE) and by de novo shoot organogenesis (DNSO). Efficient regeneration by direct SE was achieved using immature zygotic embryos as explants incubated on PGR-free media, and the production process was maintained in culture thanks to highly efficient secondary SE. Conversely, efficient regeneration by indirect DNSO was achieved using entire seedlings as explants and adding only cytokinin (CK) without the need for exogenous auxin. Comprehensive phytohormone analyses revealed that different exogenously applied CKs differentially affected the composition of endogenous phytohormones and induced changes in the expression of cell cycle-related genes and other genes involved in the organogenic response. The addition of high sucrose concentrations to the nutrient media failed to induce the formation of stem tubers in in vitro culture, but revealed a complex interaction with exogenously applied CKs, interfering with both the endogenous phytohormonome and the expression of organogenesis-related genes. Our work has provided substantial biotechnological advances in the field of in vitro regeneration of kohlrabi, as well as in understanding the underlying phytohormonal regulation. The review aims to introduce kohlrabi to the scientific community as a model system for both basic and applied research, while we continue seeking answers to the outstanding questions and trying to pave the way for the development of more resistant varieties.
•Leaf area index is measured using direct and indirect methods with several setups.•Direct methods are destructive, expensive, laborious and time-consuming.•Less laborious indirect methods yielded ...precise values in kohlrabi and lettuce.•Digital photography is a good alternative to destructive methods in these crops.
The dimensionless leaf area index (LAI) is a fundamental crop characteristic. Since the direct measurement of LAI or leaf area is labour intensive and destructive, fast and reliable indirect methods have been devised to estimate LAI of different crops. The objective of this work was to test indirect methods for the non-destructive estimation of LAI in kohlrabi (Brassica oleracea var. gongylodes L.) and lettuce (Lactuca sativa var. capitata L.). Focusing on the gap fraction methodology, digital photographs and simultaneous radiation interception measurements were taken using a Li-Cor plant canopy analyser (LAI-2200) on 12 sampling dates from planting to harvest, with concurrent destructive estimations of the leaf area. Several geometric protocols of the LAI-2200 and inversion algorithms of the accompanying software were evaluated. Very good indirect-direct LAI relationships were obtained for kohlrabi (R2>0.97, n=12) and lettuce (R2>0.99, n=9) for the most suitable protocols and algorithms.
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