Marie Bjelková

Hemp and linseed are nutritionally valuable commodities that exhibit considerable varietal differences in composition. Nutrient composition was evaluated in 12 hemp and 11 linseed varieties, including commercially cultivated varieties from the EU Common Catalogue and newly bred lines, to assess varietal variability. Field experiments were conducted under uniform agronomic conditions in the Czech Republic during a single growing season using field-block samples. Analyses included proximate composition (dry matter, crude protein, fat, fiber, ash), fatty acid and amino acid profiles, carotenoids, vitamins, and cannabinoid content. Statistical evaluation was performed using a General Linear Model with Duncan’s multiple range test (p < 0.05). Significant differences were observed across most parameters, indicating substantial inter-varietal variability under the experimental conditions. Fat content ranged from approximately 200 to 377 g/kg in both oilseeds, with lipids dominated by polyunsaturated fatty acids, particularly linoleic (n-6) and α-linolenic (n-3) acids. Hemp and linseed show potential as alternative plant protein sources in animal nutrition, but further digestibility and feeding studies are needed to confirm their suitability as partial soybean meal substitutes. Varietal selection may contribute to improved nutritional quality while influencing levels of undesirable constituents such as Δ⁹-THC in hemp.

The research is focused on the quantitative evaluation of the flaxseed (Linum usitatissimum L.) proteome at the level of seed cake (SC), fine flour—sieved a fraction below 250 µm (FF)—and protein concentrate (PC). The evaluation was performed on three oilseed flax cultivars (Agriol, Raciol, and Libra) with different levels of α-linolenic acid content using LC-MS/MS (shotgun proteomics) analysis, which was finalized by database searching using the NCBI protein database for Linum usitatissimum and related species. A total of 2560 protein groups (PGs) were identified, and their relative abundance was calculated. A set of 33 quantitatively most significant PGs was selected for further characterization. The selected PGs were divided into four classes—seed storage proteins (11S globulins and conlinins), oleosins, defense- and stress-related proteins, and other major proteins (mainly including enzymes). Seed storage proteins were found to be the most abundant proteins. Specifically, 11S globulins accounted for 41–44% of SC proteins, 40–46% of FF proteins, and 72–84% of PC proteins, depending on the cultivar. Conlinins (2S albumins) were the most abundant in FF, ranging from 10 to 13% (depending on cultivar). The second most important class from the point of relative abundance was oleosins, which were represented in SC and FF in the range of 2.1–3.8%, but only 0.36–1.20% in PC. Surprisingly, a relatively high abundance of chitinase was found in flax products as a protein related to defence and stress reactions.

Plant foods are receiving increasing attention as a valuable source of health beneficial compounds. Understanding the impact of growing conditions on the quality of milk thistle is critical for determining appropriate agro-ecological and agro-economic parameters for its production and, subsequently, food products rich in health-beneficial compounds. For this purpose, a randomized milk thistle cultivation trial was established in the experimental field of Agritec Plant Research Plc. in Šumperk, Czech Republic, and carried out for two subsequent growing seasons in 2020 and 2021. The milk thistle achenes, variety Mirel, were sown in the row width of 12.5, 25 and 37 cm; and the qualitative parameters of each field trial such as achenes yields, silymarin complex determination and also antioxidant assessment (total phenolic content, total flavonoids content, DPPH and ABTS radical scavenging activity) were evaluated. The environmental impact of the extraction process was reduced by using pressurized liquid extraction with 60% EtOH (v/v). The weather conditions during the trial as well as the row spacing of milk thistle sowing were revealed to have a significant influence on the evaluated parameters (p ≤ 0.05). The highest yields of evaluated parameters were obtained for the growing season 2021 and the row spacing of 37 cm.

The utilization of plant by-products as functional food ingredients has received increasing attention in the last decade. One such by-product generated during milk thistle oil pressing is oilseed cakes, which could be used as a novel food ingredient. Therefore, the study aimed at investigating the effects of the addition of milk thistle oilseed cake (MTOC) flour fractions obtained via dry sieving, differing in particle size (unsieved; coarse: >710 µm; medium: 315–710 µm; and fine: <315 µm), on the quality of gluten-free bread and stability of silymarin during breadmaking. The 10% addition of the fractions into gluten-free bread increased the protein, fibre, fat, ash and silymarin content. The breads with the coarse fraction had the highest content of fibre, whereas the breads with the fine fraction excelled in protein, fat and ash content. The medium fraction was characterized as the richest source of silymarin, whilst the fine fraction was the poorest. Silymarin constituents were slightly released during dough rising but also partially decomposed during baking; moreover, silydianin was the most susceptible and degraded the most. The enriched breads had better sensory and textural properties compared to the control bread. The results suggest that MTOC flour fractions can improve the potential health benefits and nutritional profile of gluten-free bread.

Milk thistle [Silybum marianum (L.) Gaertn.] achieved a significant increase in interest over the past few years from local and foreign pharmaceutical corporations. The silymarin complex of constituents extracted from milk thistle achenes provides compelling health benefits primarily thanks to antioxidant activities and hepatoprotective effects. However, consuming mycotoxin-contaminated plant material can cause immunosuppression and hepatotoxic problems. The aim of this study was to develop and validate a method for the determination of mycotoxin content in milk thistle. Fusarium toxins as T-2 and HT-2 toxins in grown milk thistle harvested from a breeding station in the Czech Republic during 2020–2021 were studied. The analysis of T-2 and HT-2 toxins was performed by UPLC-MS/MS after immunoaffinity columns EASI-EXTRACT^® T-2 & HT-2 clean up. All analysed samples of milk thistle were contaminated with T-2 toxin and HT-2 toxin. The content of T-2 toxin in the samples from 2020 was in the range of 122.7–290.2 µg/kg and HT-2 toxin 157.0–319.0 µg/kg. In 2021, the content of T-2 toxin was in the range of 28.8–69.9 µg/kg and HT-2 toxin was 24.2–75.4 µg/kg. The results show that the climatic conditions of the year of harvesting have a highly statistically significant effect on the content of T-2 and HT-2 toxins in milk thistle.

Naturally occurring lignans are present in seeds, nuts, cereals, vegetables, and fruits. Lignans play various roles in plants and their multipurpose functions of different organisms including humans is considerable. They are involved in plant defence mechanisms through their antioxidant, antiviral, antibacterial, and antifungal properties. The lignans content may be affected by a variety of factors such as genotype, tissue type, geographic origin, local environmental conditions, nutrition, and plant maturity. Interactive relationships between individual factors are also considered. This review aimed to summarize the biological functions of lignans for plants and empasize the importance of these compounds for the added value of individual genotypes of plant food resources. Understanding the biological functions of lignans in plants can provide solutions to the ever-increasing requirements for the production of functional foods. Flaxseed is the richest source of lignans, and as such is considered the model species for lignans studies. Within our review, one paragraph is focused on the properties and biological functions of flax lignans.

Oilseed cakes are produced as a by-product of oil pressing and are mostly used as feed. Their use for human consumption is due to the functional properties and benefits for human health. Herein, oilseed cake flours of eight species (flax, hemp, milk thistle, poppy, pumpkin, rapeseed, safflower, sunflower) were sieved into fractions above (A250) and below (B250) 250 µm. The chemical composition, SDS-PAGE profiles, colour, functional properties and antioxidant activities of these flours were evaluated. The B250 fractions were evaluated as being protein and ash rich, reaching crude protein and ash content ranging from 31.78% (milk thistle) to 57.47% (pumpkin) and from 5.0% (flax) to 11.19% (poppy), respectively. A high content of carbohydrates was found in the flours of hemp, milk thistle and safflower with a significant increase for the A250 fraction, with a subsequent relation to a high water holding capacity (WHC) for the A250 fraction (flax, poppy, pumpkin and sunflower). The A250 milk thistle flour was found to have the richest in polyphenols content (TPC) (40.89 mg GAE/g), with the highest antioxidant activity using an ABTS•+ assay (101.95 mg AAE/g). The A250 fraction for all the species exhibited lower lightness than the B250 fraction. The obtained results indicate that sieving oilseed flour with the aim to prepare flours with specific functional characteristics and composition is efficient only in combination with a particular species.

Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis, the scientific journal of the Mendel University in Brno, Czech Republic

The aim of this work was to verify usefulness of image analyses software to determine genotype differences on quantitative linseed traits (Linum usitatissimum L...