Comparative Metabolomic Analysis of Rapeseeds from Three Countries

Metabolomics applications for plant-based foods origin tracing, cultivars identification and processing: Feasibility and future aspects

Metabolomics, the systematic study of metabolites, is dedicated to a comprehensive analysis of all aspects of plant-based food research and plays a pivotal role in the nutritional composition and quality control of plant-based foods. The diverse chemical compositions of plant-based foods lead to variations in sensory characteristics and nutritional value. This review explores the application of the metabolomics method to plant-based food origin tracing, cultivar identification, and processing methods. It also addresses the challenges encountered and outlines future directions. Typically, when combined with other omics or techniques, synergistic and complementary information is uncovered, enhancing the classification and prediction capabilities of models. Future research should aim to evaluate all factors affecting food quality comprehensively, and this necessitates advanced research into influence mechanisms, metabolic pathways, and gene expression.

Oilomics: An important branch of foodomics dealing with oil science and technology

Oil is one of three nutritious elements. The application of omics techniques in the field of oil science and technology is attracted increasing attention. Oilomics, which emerged as an important branch of foodomics, has been widely used in various aspects of oil science and technology. However, there are currently no articles systematically reviewing the application of oilomics. This paper aims to provide a critical overview of the advantages and value of oilomics technology compared to traditional techniques in various aspects of oil science and technology, including oil nutrition, oil processing, oil quality, safety, and traceability. Moreover, this article intends to review major issues in oilomics and give a comprehensive, critical overview of the current state of the art, future challenges and trends in oilomics, with a view to promoting the optimal application and development of oilomics technology in oil science and technology.

Understanding fatty acid composition and lipid profile of rapeseed oil in response to nitrogen management strategies

The fatty acid composition of rapeseed seeds plays an important role in oil quality for human nutrition and a healthy diet. A deeper understanding of fatty acid composition and lipid profiles in response to different nitrogen managements is critical for producing healthier rapeseed oil for the human diet. The fatty acid composition and lipid profiles were characterized through targeted GC-MS and lipidomics analysis (UPLC-MS) in this study. The results showed that nitrogen management significantly altered the fatty acid composition, thereby influencing oil quality when it is used to maximize the seed yield of rapeseed. Several fatty acid components (particularly oleic acid, linoleic acid, and linolenic acid) decreased significantly with increasing N application rate. A total of 1212 differential lipids in response to different N levels in the two varieties were clearly identified, that can be categorized into five classes, including 815 glycerolipids (GLs), 195 glycerophospholipids (GPs), 155 sphingolipids (SPs), 32 sterols (STs), and 15 fatty acyls (FAs). These differential lipids are likely to participate in lipid metabolism and signal transduction. Co-expression lipid modules were determined, and the key lipids, such as triglyceride (20:0/16:0/16:0; 18:0/18:1/18:3; 8:0/11:3/18:1), were found to be strongly related to several predominant fatty acids such as oleic acid and linoleic acid. The results further imply that some identified lipids are involved with lipid metabolism and could affect the fatty acid composition, which provide a theoretical guidance for increasing seed oil in Brassica napus.

The Yeast Fermentation Effect on Content of Bioactive, Nutritional and Anti-Nutritional Factors in Rapeseed Meal

The aim of this study was to evaluate the changes in the content of bioactive, nutritional and anti-nutritional factors in rapeseed meal that was fermented with Saccharomyces cerevisiae or Saccharomyces boulardii yeasts at two different periods of time, for improvement of nutritional characteristics in piglets’ feeding. The fermentation has reduced the content of two anti-nutritional factors, intact glucosinolates and 3-butyl isothiocyanate, by 51.60–66.04% and 55.21–63.39%, respectively, by fermentation with either Saccharomyces cerevisiae or Saccharomyces boulardii for 24 h. The fermentation by these yeasts also lowered the content of total polyphenolic compounds by 21.58–23.55% and antioxidant activity (DPPH) by 17.03–21.07%. Furthermore, the content of carbohydrates and organic acids has dramatically decreased between 89.20 and 98.35% and between 31.48 and 77.18%, respectively. However, the content of some individual phenolic acids (gallic, p-coumaric, sinapic) and crude protein content (10–13%) has been increased. Thus, the results showed that fermentation with Saccharomyces cerevisiae or Saccharomyces boulardii has reduced the content of antinutritive factors and increased the protein content of the rapeseed meal, without major adverse effects on its overall nutritive value.

Identifying Key Metabolites Associated with Glucosinolate Biosynthesis in Response to Nitrogen Management Strategies in Two Rapeseed (Brassica napus) Varieties

A high glucosinolate (GSL) concentration, an undesirable substance, has severely restricted rapeseed (Brassica species) development. We performed widely targeted metabolomics analysis based on the ultra-high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESI-MS/MS) technology to analyze the metabolic profiles and identify the differential metabolites and GSL components in response to different nitrogen (N) levels in two rapeseed varieties. A total of 341 metabolites and 38 GSL components were detected in the seeds. A total of 188 differential metabolites, including 34 GSL components, were identified in response to different treatments, which were mapped into 2-oxocarboxylic acid metabolism, tryptophan metabolism, and GSL biosynthesis. Key indicators of GSL components highly responsible for different N levels under two contrasting varieties were recognized, i.e., 1-methylpropyl GSL and 4-methylthiobutyl GSL. This study suggests that the efficient N management and variety selection are important strategies for developing rapeseed with low GSLs.

Time-series eco-metabolomics reveals extensive reshuffling in metabolome during transition from cold acclimation to de-acclimation in an alpine shrub

Recording environmentally induced variations in the metabolome in plants can be a promising approach for understanding the complex patterns of metabolic regulation and their eco-physiological consequences. Here, we studied metabolome-wide changes and eco-physiological adjustments occurring across the year at high elevation environments in the leaf tissue of Rhododendron anthopogon, an alpine evergreen shrub of the Himalaya. New leaves of R. anthopogon appear after the snow-melt and remain intact even when the plants get covered under snow (November-June). During this whole period, they may undergo several physiological and biochemical adjustments in response to fluctuating temperatures and light conditions. To understand these changes, we analyzed eco-physiological traits, that is, freezing resistance, dry matter content and % of nitrogen and the overall metabolome across 10 different time-points, from August until the snowfall in November 2017, and then from June to August 2018. As anticipated, the freezing resistance increased toward the onset of winters. The leaf tissues exhibited a complete reshuffling of the metabolome during the growth cycle and time-points segregated into four clusters directly correlating with distinct phases of acclimation: non-acclimation (August 22, 2017; August 14, 2018), early cold acclimation (September 12, September 29, October 11, 2017), late cold acclimation (October 23, November 4, 2017), and de-acclimation (June 15, June 28, July 14, 2018). Cold acclimation involved metabolic progression (101 metabolites) with an increase of up to 19.4-fold (gentiobiose), whereas de-acclimation showed regression (120 metabolites) with a decrease of up to 30-fold (sucrose). The changes in the metabolome during de-acclimation were maximum and were not just a reversal of cold acclimation. Our results provided insights into the direction and magnitude of physiological changes in Rhododendron anthopogon that occurred across the year.

The Mediterranean and Nordic Diet: A Review of Differences and Similarities of Two Sustainable, Health-Promoting Dietary Patterns

The Mediterranean diet (MD) and the Nordic diet (ND) share more similarities than differences. Both diets are based on typical local and seasonal foods, share similar nutritional recommendations based on plant-based dietary principles, and are both now orienting toward environmental protection and sustainability. The main difference between the two diets is the primary fat source. Olive oil is the synonym for MD while the ND uses more rapeseed/canola oil. While longitudinal epidemiological studies support adherence to MD as a way to prevent chronic diseases, ND still needs more such studies because the current results are discrepant. Notably, studies that assessed the association between both diets and lower risks of chronic diseases, disability, and mortality from specific and all causes, implied that ND could also have an advantageous effect as MD. Hopefully, there will be more longitudinal and large prospective studies in the future that will provide more evidence-based recommendations.

Comparative proteomics analysis reveals the molecular mechanism of enhanced cold tolerance through ROS scavenging in winter rapeseed (Brassica napus L.)

Two winter rapeseed cultivars, "NS" (cold tolerant) and "NF" (cold sensitive), were used to reveal the morphological, physiological, and proteomic characteristics in leaves of plants after treatment at -4°C for 12 h(T1) and 24 h(T2), and at room temperature(T0), to understand the molecular mechanisms of cold tolerance. Antioxidant activity and osmotic adjustment ability were higher, and plasma membrane injury was less obvious, in NS than in NF under cold stress. We detected different abundant proteins (DAPs) related to cold tolerance in winter rapeseed through data-independent acquisition (DIA). Compared with NF, A total of 1,235 and 1,543 DAPs were identified in the NSs under T1 and T2, respectively. Compared with NF, 911 proteins were more abundant in NS only after cold treatment. Some of these proteins were related to ROS scavenging through four metabolic pathways: lysine degradation; phenylalanine, tyrosine, and tryptophan; flavonoid biosynthesis; and ubiquinone and other terpenoid-quinone biosynthesis. Analysis of these proteins in the four candidate pathways revealed that they were rapidly accumulated to quickly enhance ROS scavenging and improve the cold tolerance of NS. These proteins were noticeably more abundant during the early stage of cold stress, which was critical for avoiding ROS damage.

Low-Cost Investment with High Quality Performance. Bleaching Earths for Phosphorus Reduction in the Low-Temperature Bleaching Process of Rapeseed Oil

Rapeseed oils are a valuable component of the diet. Mostly, there are refined oils deprived of valuable nutrients in the market, hence in recent times cold-pressed and unrefined oils have been available and popular among consumers. However, the low yield of this oil makes this product expensive. The aim of the study was to analyse the effectiveness of phosphorus reduction in crude oils, cold- and hot-pressed in the low-temperature bleaching process. Eight market-available bleaching earths was compared. The effectiveness of 90% was found with 2% (m/m) of Kerolite with hydrated magnesium silicate. An increase in the share of earths to 4% (m/m) resulted in the effectiveness of phosphorus reduction >90% in seven out of eight analysed cases. Bentonite activated with acid with the lowest MgO content was characterised by low efficiency <64%. The research shows that the effectiveness of phosphorus reduction was significantly affected by the composition of earths applied in the bleaching process at ambient temperature. The results of research confirm the high effectiveness of the process as it is not necessary to heat up the oil before the bleaching process. This method is recommended for existing and new industrial plant for two-stage rapeseed oil pressing.

Abscisic Acid Receptors Modulate Metabolite Levels and Phenotype in Arabidopsis Under Normal Growing Conditions

Abscisic acid (ABA) is a vital phytohormone that accumulates in response to various biotic and abiotic stresses, as well as plant growth. In Arabidopsis thaliana, there are 14 members of the ABA receptor family, which are key positive regulators involved in ABA signaling. Besides reduced drought stress tolerance, the quadruple and sextuple mutants (pyr1pyl1pyl2pyl4 (1124) and pyr1pyl1pyl2pyl4pyl5pyl8 (112458) show abnormal growth phenotypes, such as decreases in yield and height, under non-stress conditions. However, it remains unknown whether ABA receptors mediate ABA signaling to regulate plant growth and development. Here, we showed the primary metabolite profiles of 1124, 112458 and wild-type (WT) plants grown under normal conditions. The metabolic changes were significantly different between ABA receptor mutants and WT. Guanosine, for the biosynthesis of cyclic guanosine 3′,5′-monophosphate (cGMP), is an important second messenger that acts to regulate the level of ABA. In addition, other amino acids were increased in the 112458 mutant, including proline. These results, together with phenotype analysis, indicated that ABA receptors are involved in ABA signaling to modulate metabolism and plant growth under normal conditions.