Mustard Seeds as a Bioactive Component of Food

ABSTRACT Mustard is a plant that is eagerly cultivated by farmers, due to its mobility across agroclimatic conditions and its high yield. Mustard seeds have thus become a valuable source of many bioactive ingredients, such as polyunsaturated fatty acids and antioxidants (carotenoids, phenolic compounds, tocopherols). The increasingly popularity of natural ingredients in food creation and other industries has made mustard a material for creating new products. The mustard-infused foods developed here have improved properties over the controls. The most common improvements relate to microbiological safety, longer shelf life, slower lipid oxidation, higher protein content and overall better product acceptability. The high content of erucic acid in its seeds, as well as of glucosinolates, mean that mustard has not been widely used in the human food industry or as animal feed. Mustard varieties with reduced levels of erucic acid and glucosinolates are now available on the market. This literature review characterizes the bioactive ingredients present in mustard seeds and presents the already developed possibilities of using mustard seeds in food and as a health-promoting product.


Introduction
The accelerating pace of life and the lack of time to prepare meals saw the rise in popularity of readymade meals and semifinished products. Producers of such products generally focused on affordability and taste, showing less interest in the products' composition. [1] It is only in recent years, when the number of people with cardiovascular diseases, cancer, obesity or allergies increased, did manufacturers begin to combine food trends with their impact on health. People read the labels of the products they buy more carefully now and, where possible, prepare meals from scratch. The trend of healthy nutrition is increasing from year to year, requiring producers to alter their products. [2] The range of healthy food products continues to expand. At the same time, both researchers and producers are looking for forgotten plants that have not been used in the kitchen for a long time, and which are characterized by the presence of bioactive compounds -such as black lilac or Jerusalem artichokes.
Mustard is a plant, known since prehistoric times, that possesses a high level of bioactive ingredients. There are several species, including white mustard (Sinapsis alba L.), black mustard (Brassica nigra L.), brown mustard (Brassica juncea L.), Ethiopian mustard (Brassica carinata A. Braun), rocket (Brassica eruca L.) and wild mustard (Sinapsis arvensis L.). [3] Table 1 compares the mentioned mustard varieties in terms of their cultivation.
Mustard is an annual plant. It belongs to the Brassicaceae family (formerly Cruciferae). White mustard probably originates from the Mediterranean but spread throughout Northwestern Europe, Russia, Japan, North and South America, Australia, New Zealand, the Middle-East, India, North Africa, and China. It is a spring plant with a vegetation period of 80-125 days. [3] White mustard is honey plant, is drought resistant, and prevents the spread of the sugarbeet nematode. The use of

Characterization of lipid compounds in mustard
Mustard seeds have a high fat content of 23%-47%, dominated by erucic acid (26.5%-36.5%). Depending on the species, the proportion of other fatty acids varies -for example, white mustard oil has a high oleic acid content (22%); in brown and black mustard oil, linoleic acid is most common (19.5%-22%). Linolenic acid is also found at significant levels (9%-15%) in the seeds of all species of mustard. [3] Because of its high fat content, mustard can be used as a spring oil plant. Mustard oil is used in cooking for its hot and spicy flavor to food. It is most popular in Asian countries especially in India and China. A problem with mustard oil is the level of erucic acid (cis 13-docosenoic acid; Fig. 1) -a monounsaturated fatty acid that accumulates in the body's tissues. A diet containing large amounts of erucic acid can lead to myocardial steatosis. Erucic acid can also cause liver enzymes to malfunction, and additionally reduces fertility. [11] According to EFSA, the tolerable daily intake of erucic acid has been established at 7 mg/kg body weight. [12] To be able to use mustard as a food Table 1. Comparison of mustard varieties in terms of its cultivation.
White mustard Black mustard [4] Brown mustard Wild mustard [5]   material, it should thus contain the lowest possible levels of erucic acid. The first reports on obtaining the zero-erucic acid variety were presented by Fernandez-Escobar et al. [13] Similar research is being conducted in Canada by the Rakow team. [14,15] A transgenic zero-erucic variety has also emerged in India. [16,17] However, genetically modified products are a public concern because of the uncertain scientific approach to the matter. In Poland, Piętka et al. [6] also looked into obtaining white mustard seeds with minimum levels of erucic acid and increased fat content in the seeds. By crossing Polish varieties with other lines with an erucic acid content below 1.5% and a higher fat content (30.2%), a new non-erucic variety was obtained. [6] The characteristics of the obtained white mustard seeds means it would be possible to use them in the production of mustard seed food oil with high levels of oleic acid (> 65%), an appropriate proportion of n-3 and n-6 (1.5:1) acids, and low levels of undesirable saturated fatty acids. The obtained fatty acid ratio gives even greater benefits from the use of seeds/ mustard oil. Among vegetable oils, there are not many types that are characterized by a higher level of omega-3 fatty acids than omega-6 fatty acids. Only flax, perilla and chia oils also have an omega-3 to omega-6 ratio higher than 1:1. [18][19][20][21][22] Omega-3 fatty acids are not synthesized by the human body and must be supplied with food. Omega-3 fatty acids are responsible for the protection of the circulatory system against diseases, it is an essential component of cell membranes, is responsible for the proper development of the brain. For this reason, the new variety of white mustard ("Warta") is a valuable source of omega-3 fatty acids, which we still have too little in our diet. That new variety "Warta" was registered in 2012 in Poland. [6] To use mustard oil with a high erucic acid content, it is also possible to blend mustard oil with other conventional oils that are without erucic acid. The use of oils for this purpose: sesame, sunflower, safflower, groundnut, soybean, olive oil, rice bran, palm oil made it possible to obtain blends of oils using mustard oil, with a reduced percentage of erucic acid, a better ratio of fatty acid groups SFA: MUFA: PUFA (1: 2: 1), rich in bioactive substances derived from mustard oil. [23] The modification of fatty acid composition in mustard seeds can also be carried out through the use of appropriate agrotechnical treatments. The use of herbicides during cultivation may also affect the quality characteristics of mustard seeds. The biological activity of herbicides can affect plant metabolism, reducing fat levels and increasing protein content. Depending on the mustard variety, herbicides may increase the proportion of saturated or monounsaturated acids. [24] The presence of cadmium in the soil, and fertilization with nitrogen in amounts exceeding 1 g N/pot, also reduces the total lipid content of mustard seeds. [25,26] Mustard seeds are high in fat, but the potential for efficient pressing of mustard oil by industry can be increased by modifying the preparation of the mustard seeds for pressing: microwave exposure for 6 minutes can increasing the efficiency of expelling mustard seed oil. This is associated with a reduction in the water content of the seeds, which makes the mustard seed tissues break more easily. [27,28] Additional benefits associated with microwave processing are the reduction of the average content of phytates, erucic acid and glucosinolates. In addition, total antioxidant activity, β-carotene and tocopherol content increased.

Characterization of glucosinolates in mustard seeds
Plants of the Brassicaceae family are rich sources of glucosinolates, which are mainly found in the seeds. These are a group of secondary metabolites -thioglycosides, rich in sulfur. The structure of glucosinolates is shown in Fig. 2. Glucosinolates can be divided into three groups, depending on the type of amino acid in the side chain (aliphatic, aromatic, or indole). In the Brassicaceae plant family, the most common glucosinolates are sinalbin (0.1-1.1% of white mustard), sinigrin (0.8%-0.9% of brown mustard and 0.4%-0.9% of black mustard), gluconapine, glucobrassicin, progoitrin, glucoiberin, glucoraphanin, and neoglucobrassicin. [3] Mustard seeds from different geographical regions show heterogeneity of their glucosinolate profiles. [30] Glucosinolates are durable and resistant to increased temperatures. They are easily hydrolysed under the influence of the enzyme myrosinase, which occurs in the tissues of Brassicaceae plants and is released from the tissues during cell damage, crushing, or other processing. Myrosinase and glucosinolates are located in another compartment of tissues. The enzymatic activity of myrosinase depends on the mustard species. Myrosinase from brown mustard has the highest enzymatic activity (2.75 un/mL in brown mustard; 1.50 un/mL in black mustard; 0.63 un/mL in white mustard). [31] Myrosinase loses activity at 60°C, but is more stable to pressure. Inactivation of the enzyme occurs at a pressure of 700 MPa. At 300 MPa, the enzyme is only deactivated at 70°C. [32] Brown and black mustard myrosinase are more resistant to pressure and temperature then myrosinase from white mustard. [31] The reaction products of the hydrolysis of glucosynolates by myrosinase are glucose and unstable aglycones. Aglycones instantly rearrange to thiocyanates, isothiocyanates, nitriles, epithionitriles, and indoles. The hydrolysis reaction and its products is presented in Fig. 3. Myrosinase from mustard is more stable then myrosinase from broccoli. This information is relevant to the cooking of broccoli. The main glucosinolate in broccoli is glucoraphanin. The product of the hydrolysis of raw broccoli is sulforaphane nitrile, while that of cooked broccoli is sulforaphane. However, during cooking, myrosinase is inactivated and glucosinolate hydrolysis stops. The microflora present in the human digestive tract is also capable of producing thioglucosidases, but in amounts much lower than those of enzymes present in plants. The addition of raw or slightly cooked mustard seed to cooked broccoli provides myrosinase, which is necessary for further hydrolysis. [33] Due to the inactivation of myrosinase during the cooking of broccoli, the level of sulforaphane in the urine of a person consuming broccoli is equal to 9.8 μmol/g creatinine. The addition of powdered mustard seeds to cooked broccoli has been found to significantly increase urinary sulforaphane levels to 44.7 μmol/g creatinine. [34] Other glucosinolate is sinigrin. Sinigrin degradation products depend on the pH of the environment and the presence of ferrous ions. [32] The degradation products include allyl isothiocyanate (AITC), allyl thiocyanate, allyl cyanide, and 1-cyano-2,3-epithiopropane. In mustard seeds in neutral pH, AITC is produced from sinigrin, which is responsible for the pungent odor of crushed mustard seeds. [35] Also, increases in relative humidity and temperature result in increased AITC release. [36] Figure 2. Structure of glucosinolates: sinigrin (R1) and sinalbin (R2), based on Choubdar et al. [29] Figure 3. Glucosinolate hydrolysis reaction under the influence of the myrosinase enzyme. Reaction products may be isothiocyanates (1), nitriles (2), or thiocyanates (3), based on Choubdar et al. [29] Headspace analysis of mustard seeds has confirmed the action of myrosinase in damaged cells. Grinding mustard seeds leads to higher amounts of AITC. The presence of mustard seed fat also slows the release of AITC. [37] AITC has been demonstrated to have extensive antimicrobial properties for bacteria, yeast, and molds in both the liquid and gas phases. The essential oil of mustard seed, whose main component is AITC (71.06%), has also a broad spectrum of antimicrobial action. Comparing essential oil and pure AITC, it can be stated that the antimicrobial activity of pure AITC is slightly stronger than that of the essential oil. Both the essential oil and AITC have confirmed action against the bacteria Staphyloccocus aureus, Micrococcus luteus, Staphylococcus epidermidis, Escherichia coli, Bacillus subtilis, Shigella sonnei, Salmonella lignieres, Pseudomonas aeruginosa, and Pseudomonas fluorescens. [38] Essential mustard oil acts on bacteria by decreasing intracellular ATP concentration and lowering pH and increasing intracellular ATP concentration. This leads to damage to the bacterial cell membranes. [39] However, the strong smell and volatility of the AITCs used represent a problem. AITC is characterized by a sharp taste and aroma reminiscent of horseradish. The possibility of using polymeric carriers for encapsulated AITC is therefore being investigated. [35] The use of temperature to inactivate the enzyme results in a more sensorially acceptable product. [40] 4-hydroxybenzyl isothiocyanate is formed from sinalbin. It is found in white mustard and is responsible for the hot mouthfeel. This compound may have higher antimicrobial potential than AITC. [29] White mustard seed essential oil is more effective against gram negative bacteria than gram positive. Of the microorganisms tested, Salmonella enteritidis and Schizosaccharomyces pombe (growth inhibition with mustard seed oil at 2.1 g/L) were the most sensitive. White mustard essential oil has bactericidal and bacteriostatic properties. [36,37] Except for the presence of erucic acid in mustard seeds, a large amount of glucosinolates is also a problem. The pomace obtained during the pressing of the oil is often used as animal feed. The high content of glucosinolates in the pomace after pressing mustard oil makes it impossible to use it for animals. High glucosinolate content in animal diets can cause growth inhibition and iodine metabolism disorders. [6] The research on reducing the content of glucosinolates in mustard was carried out by Rakow's team. In 2001, researchers made a cross of brown mustard with high glucosinate rapeseed. The stable nullisomic line of brown mustard has a lower glucosinolate content. [41] Also in Poland, Piętka et al. were focused on obtaining seeds with a low glucosinolate content, given the possibility of using postextraction meal as animal feed. [6] By crossing Polish varieties with others, lines with erucic acid content below 1.5%, higher fat content (30.2%), and reduced glucosinolate content were obtained (before selection: 151 µmol/g; after selection: 15 µmol/g). Due to the reduced glucosinolate content, the extraction meal can be used as a high-protein animal feed. [6] For humans, more and more reports are being made about the positive effects of glucosinolates on human health. Unlike animals, we have a more varied diet, which means we consume less glucosinolates. These amounts have a positive effect on the body and have anti-carcinogenic properties. [42,43] Comparing the effects of oil extract on different human cancer cell lines (breast, prostate, lung, cervix, colon), the greatest effect of the extract was found in breast line cancer cells. [44] Summarizing the information on glucosinolate hydrolysis products, they show a number of positive properties; they are antioxidant, fungicidal, bioherbicidal and anticancer. [44]

Antioxidant compounds in mustard seeds
Antioxidant compounds, such as phenolic compounds, are found in mustard seeds, including 3,4-dihydroxybenzoic acid, ferulic acid, and sinapic acid. In black mustard seeds, rutin occurs alongside these compounds. Extraction of phenolic compounds from mustard seeds is best performed using a mixture of water and acetone in equal proportions. [45] Given that mustard seed antioxidants could be used as an ingredient to protect against food spoilage, research into how to most effectively extract them has been carried out. The use of ultrasound can reduce the required temperature and extraction time. [46] The highest FRAP and DPPH values were obtained using a 50% methanol solution and ultrasound for 30 min (4 W/min). [47] In addition, germination conditions for individual mustard varieties can be selected to improve the antioxidant properties of the seeds. For white and black mustard seeds, total phenolic compounds could be 49% and 44% higher, respectively, than of nongeminated mustard seeds. [48] Phenolics can also be extracted from mustard seed oil, but in smaller amounts. In flour and seeds it was 11-42 mg SAE/g. In mustard oil it was 0.1-0.3 mg SAE/g. The differences between the amount of phenolics separately in flour and separately in oil are related to the genotype of the plants, environmental factors and degree of maturity. [49,50] Tocopherols also show antioxidant activity in mustard seeds. [40,51] The amount of tocopherols varies between the mustard species. The lowest amount of tocopherols was found in black mustard (453.4 mg/kg), a higher amount of tocopherols was found in oriental mustard (602.1 mg/kg). The greatest amounts are found in white mustard (886.95-952.2 mg/kg depending on the variety).
Mustard seed oil, obtained after pressing the seeds, has a relatively high sensitivity to oxidation. To improve this, the seeds can be roasting before pressing. Roasting for 5 minutes at 165°C does not affect the fatty acid. However, during oil storage, the amount of hexanal (associated with the auto-oxidation of oil) in seeds after roasting made up only 13% of the amount of hexanal in the seeds that were not roasted. Oxidative stability is increased by the formation of 2,6-dimethoxy-4-vinylphenol also known as 4-vinyl syringol (canolol) by thermal decarboxylation of sinapic acid. [52] The decarboxylation reaction is presented in Fig. 4. Canolol is a very strong antioxidant (higher then α-tocopherol and flavonoids) and additionally has antimutagenic properties. [49,[53][54][55][56] Additionally, during the heating of white mustard, an increase in the amount of tocopherols was observed. In the temperature between 120°C and 140°C, the increase was even 7-9%. [57] An important component of mustard seeds are also carotenoids, i.e. natural pigments. The mustard seeds contain mainly lutein and β-carotene. Roasting mustard seeds does not alter the amount of carotenoids in the seeds. Roasting mustard seeds resulted in slower degradation of lutein during heating of roasted mustard seed oil at 160°C compared to unroasted seeds. Similar relationships were found in the case of tocopherols. The tocopherols in roasted mustard seed oil degraded more slowly than the tocopherols in unroasted mustard seed oil. [58]

Mustard as a food additives
Due to the presence of glucosinolates and antioxidants in mustard seeds, as well as their characteristic taste, they can be used as a source of bioactive compounds in food. Table 2 presents a list of tests for treating food products with mustard seeds. Researchers are currently seeking substitutes to nitrates for preserving meat products. The addition of ground mustard to meatballs can delay lipid oxidation and extend the shelf life. Sensory evaluation of such products using white mustard was more favorable than either controls or those using black and brown mustard. The addition of mustard effectively inhibits the growth of microorganisms in the product. [59] Also the effect on sausage quality of adding ground mustard seeds and autoclaved mustard seeds was assessed. The addition of mustard and acid whey, instead of nitrates, had a positive effect on the product over 90 days of storage. The pH of the product Figure 4. Thermal decarboxylation of sinapic acid and formation of 2,6-dimethoxy-4-vinylphenol (canolol), based on Wijesundera et al. [52] dropped, the antioxidant capacity increased, and there were lower oxidation-reduction potential values during storage. The TBARS value was at the same level as in the samples with nitrates. The addition of mustard seeds reduced the amount of conjugated dienes, even compared to the nitrate sample. In addition, autoclaving of mustard seeds has been found to produce higher amounts of phenolic acids. [61,62] It must be connected with production of canolol. Similarly, higher phenolic content, higher antioxidant capacity, and lower product pH were also found in fermented pearsa traditional Greek product often made as a home preparation. In general, the addition of mustard seeds to the product has resulted in overall better product acceptance by consumers. It also has a positive effect on the development of lactic acid bacteria and causes a decline in undesirable microorganisms. [64] Mustard seed extract can also be used to create an antimicrobial film on bologna sausages. Levels of viable Listeria monocytogenes on that product was reduced using mustard seed extract containing glucosinolates. [65] Edible biopolymer films from defatted mustard seed meal can be used to create food coatings or stand-alone films. Defatted mustard seed meal, which is a waste product generated during the production of mustard oil, can also be utilized, with high-pressure homogenization with 0.6% glycerol being the best preparation method tested. This is a promising material for creating biopolymer films and coatings for food packaging. [66] AITC from oriental mustard flours is capable of reducing over 90% of the aflatoxins produced by Aspergillus parasiticus produced in wheat tortillas.- [67] Similar results of AITC inhibition of aflatoxin secretion were obtained on Penicillium roqueforti, P. corylophilum, Eurotium repens, A. flavus and Endomyces fibuliger growing on rye bread. [68] The best temperature at which mustard extract is able to inhibit the growth of L. monocytogenes and Sallmonela spp. is between 4°C and 10°C. At a higher temperature, 21°C, the instability of AITC causes no inhibition of the growth of microorganisms. [69] Volatile mustard essential oil, which includes AITC, is also used to create active packaging. [70,71] From the erucic acid in mustard seed oil can be produced behenic acid. It can be used as an emulsifier in food. Mustard is one of the most allergenic products, so it was checked whether behenic acid made from mustard presented a danger to allergy sufferers. However, the amount of mustard protein present in the mustard-based emulsifier is a thousand times lower than the dose of mustard protein that causes allergies. [72] The proteins present in the mustard seeds also provide a valuable resource that can be used in food. Consumption of meat continues to drop, due to a growing awareness of problems associated with its produced. Associated with this trend is a need to replace this popular source of protein with vegetable protein. Mustard seeds, in addition to their high fat content, also have high protein content (at 18%-24%), which can serve as a source of food-grade vegetable protein. [73] Essential amino acids from mustard seeds is comparable with soy protein. [74] It is possible to produce protein isolates or protein concentrates from mustard seeds. In order to obtain the maximum efficiency of protein extraction from ground, defatted mustard seeds, it should be carried Table 2. The use of mustard seeds to improve food quality.

Research
Results References Effect of yellow, black, and brown mustard seeds on the quality of meatballs during storage.
Ground mustard seeds had a positive effect on color values, chemical, microbiological, and sensory properties of the meatballs, and extended the shelf life of the product. [59] White mustard essential oil in a sauce with particulates Mustard essential oil controlled intentionally inoculated Salmonella sp. in a frozen sauce with particulates. [60] Mustard seeds during the cooking of broccoli. Sulforaphane content increased significantly. [33] Mustard seeds in organic fermented sausage without nitriles.
Mustard seed with acid whey can protect organic fermented sausage from lipid oxidation without nitriles. [61][62][63] Mustard seeds in pears in water. Addition of mustard seeds improved overall acceptance of the final product. [64] Antimicrobial film with mustard extract on bologna sausages.
Reduction of undesirable microorganisms and longer shelf time. [65] out at a pH of 12.5. [73,75] According to recent studies, a high yield of mustard seed proteins can be achieved through high-pressure homogenization in a piston valve system. This process does not require the use of solvents, it relies only on water and the use of physical solutions. Additionally, mechanical cell disruption improves protein digestibility by increasing the release of proteins from indigestible cell structures. [76] Mustard seed protein can be used in the production of bread. Mixing wheat flour with mustard flour in the amount of 90:10 (v: v) while baking bread increases the percentage of protein in the bread by 5%. The acceptability of bread obtained by blending flours is the same as that of bread without the addition of mustard seed flour. [77] Similar results were obtained by replacing part of the wheat flour with mustard seed flour during the preparation of the biscuits. Replacing 20% of wheat flour with mustard seed flour in the case of biscuits allowed to increase the protein content in the product 2.5 times. The highest product acceptability was obtained with the addition of 15% mustard seed flour, but the addition of 20% mustard seed flour still resulted in higher acceptability than cakes without the addition of mustard seed flour. The lower acceptability in relation to the 15% addition of mustard flour was due to the change in the physical properties of the cookies, [78] or may be due to the characteristic pungent taste associated with the presence of glucosinolates. Bitterness can be reduced through preparation of extruded mustard meal concentrates. [79] Health effects of mustard consumption Mustard seeds are also rich in melatonin, and mustard melatonin extract administered to rats was found to prevent de novo cholesterol synthesis and scavenging reactive oxygen species present through hypercholesterolemia. [80] Mustard seeds are an effective antioxidant that prevents induced carcinogenesis. In addition, it has been noted to induce programmed colon cancer cell death in a study performed on normal cell cultures and the human colon cancer cell line. In mice, a mustard-seed-enriched diet reduced levels of malonaldehyde lipid peroxidation product and increased the activity of several antioxidant enzymes, such as superoxide dismutase (SOD), catalase, and glutathione peroxidase. [51,81] An interesting possible use of mustard seed is its use as a source of chemotherapeutic. Mustard cultivation in the selenium-rich areas of India made it possible to obtain mustard seeds with a high selenium content, both in the cake and in the oil. In this case, it is an additional bioactive compound present in the mustard grains. [82] Some drugs, such as paracetamol (also called acetaminophen), have toxic effects on the liver, so the ability of hydromethanolic extract of mustard seed to protect the liver has been investigated. Paracetamol may increase liver enzymes by raising levels of reactive oxygen species. Hydromethanolic extract of mustard seed prevents peroxidative degradation of membrane lipids by inhibiting the binding of activated radicals to macromolecules, while reducing liver parameters to appropriate levels. [83] Volatile oil from white mustard seed is a potential agent that can be used to increase the penetration of the skin by drugs. Volatile oil consisting mainly of AITC and isothiocyanatocyclopropane was tested for this purpose, and was found to increase the effect of three model drugs. Histopathological studies confirmed its safety for the skin when used at concentrations below 2%. [84] Synigrin obtained from the mustard seed also has many uses in medicine, including reduction of liver fibrosis, promotion of wound healing, anti-cancer properties in methyl glyoxal modification and anti-proliferative activity on carcinogen-induced hepatotoxicity. [85] The soluble dietary fiber present in mustard seed mucilage can be used in a strategy to reduce the risk of type 2 diabetes. Using this property to create puddings has allowed the reduction of blood glucose and plasma insulin levels at certain points after a meal, in people with an increased risk of developing diabetes type 2. [86] In Nepal, mustard oil is used to massage the body of newborns. No significant differences were seen when skin parameters were compared after 28 days of using mustard oil or sunflower oil, other than faster skin pH reduction with the use of sunflower oil, which may provide better protection for babies. [87] It is also possible to use mustard in analytical laboratories. The yeast Cryptococcus neoforman is one of the most common causes of infection in AIDS patients. Mustard seed extract lends a brown coloration to C. neoforman colonies while leaving Candida albicans colonies white, allowing easy identification of C. neoformans. [88]

Mustard seeds in industry
As mentioned, erucic acid has a negative impact on human health. However, it is used in industry as a green feedstock for the production of erucamid, a slip agent. It can also be used to produce behenic acid and behenic alcohol. [89] White mustard oil has also been used as an ingredient in the production of biopolyols, which are utilized in the preparation of polyurethane-polyisocyanurate foams. These foams are resistant to compression and brittleness, and can also reduce flammability. The use of this raw material is in line with the principle of sustainable development and further reduces the cost of using flame retardants. [90] The search continues for plants with high levels of lignocellulosic compounds that can be used for the production of ethanol fuels. Among plants tested for this -such as alfalfa stems, poplar, Ethiopian mustard, flax shives, and hemp hurds -fuel produced from Ethiopian mustard had the lowest level of greenhouse gas emissions, at 145% lower than conventional gasoline. Ethiopian mustard also performed best in eutrophying emissions. [91] Mustard oil has been thoroughly tested for its biodiesel production potential. Based on the standards for biodiesel parameters, it was possible to use mustard seeds to produce this fuel. [92,93] Increasing the heating temperature of mustard seeds gradual increases oil pressing efficiency, but also causes the biodiesel characteristics of the oil to deteriorate, affecting the high content of free fatty acids, peroxides, chlorophyll dyes, and phosphorus compounds. The optimal condition for oil pressing efficiency and the parameters of the resulting oil is to heat the seeds at 80°C for 60 minutes. [94] On the surface of the mustard seeds in the seed hull and bran there is a jelly-like substance, i.e. a linear hydrocolloid, which consists of various polysaccharides. The advantage of mucilage is the ability to lower the interfacial tension in water-oil and water-air emulsions. These properties enable the formation of an emulsion and gel and give the mustard flour the ability to trap fat and water. [40] White mustard has got the highest amount of mucilage, that was about 5%. Only oriental mustard does not have a mucilage coat. [73] Mustard seeds can also be a source of natural coagulating agent that can potentially be used for water treatment, especially in areas where there is a shortage of drinking water. The coagulant activity of mustard seed extract is higher (60%) compared to that of Moringa seed extract (50%) against cloudy pond water. [95] Also when removing direct black from water, the mustard seed coagulation protein performed better than the commercial product. [96] Conclusion Mustard, because of its better resistance to changing weather conditions than rape, is easily grown by farmers. The high erucic acid content of mustard seed fatty acids has always been a problem, but new mustard varieties with minimized erucic acid content allow it to be used as a food product. Its high level of linolenic acid and the presence of glucosinolates also contribute to the bioactive nature of the oil obtained from the seeds. The characteristic taste of the product allows it to be readily used in research, such as that aiming to create meat products employing mustard as a bioactive agent. It would be worth using the bioactive possibilities of mustard also in other food products.

Disclosure statement
No potential conflict of interest was reported by the author.

Funding
This work was supported by a statutory research fund at Poznan University of Life Sciences, Faculty of Food Science and Nutrition, grant number 506.752.03.00.

CRediT
The idea for the article, the literature search and data analysis, draft: A.G.