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Cyanogenic glycosides in plant-based foods available in New Zealand
Food Additives & Contaminants Part A
Abstract
Cyanogenic glycosides occur in a wide range of plant species. The potential toxicity of cyanogenic glycosides arises from enzymatic degradation to produce hydrogen cyanide, which may result in acute cyanide poisoning and has also been implicated in the aetiology of several chronic diseases. One hundred retail foods were sampled and analysed for the presence of total hydrocyanic acid using an acid hydrolysis-isonicotinic/barbituric acid colourimetric method. Food samples included cassava, bamboo shoots, almonds and almond products, pome fruit products, flaxseed/linseed, stone fruit products, lima beans, and various seeds and miscellaneous products, including taro leaves, passion fruit, spinach and canned stuffed vine leaves. The concentrations of total hydrocyanic acid (the hydrocyanic acid equivalents of all cyanogenic compounds) found were consistent with or lower than concentrations reported in the scientific literature. Linseed/flaxseed contained the highest concentrations of total hydrocyanic acid of any of the analysed foods (91-178 mg kg(-1)). Linseed-containing breads were found to contain total hydrocyanic acid at concentrations expected from their linseed content, indicating little impact of processing on the total hydrocyanic acid content. Simulation modelling was used to assess the risk due to the total hydrocyanic acid in fruit juice and linseed-containing bread.
... While the concentration of cyanogenic glycosides in flaxseed is low, flaxseed containing products such as bread have the potential of frequent consumption. Cressy et al (Cressey et al., 2013) reported a high concentration of > 50 mg/kg total hydrocyanic acid for flax seed containing products. This reported value is in agreement with other published studies (Kobaisy et al., 1996;Oomah et al., 1992;Wanasundara and Shahidi, 1998b). ...
... The enzymatic degradation of the cyanogenic glycosides in the body results in the production of toxic hydrogen cyanide and consequently cyanide poisoning. A drop in blood pressure, headache, dizziness, rapid pulse, stupor, confusion and discolouration of skin due to oxygen deficiency are reported symptoms of the cyanide poisoning (Cressey et al., 2013;Speijers, 1993). The toxic effect of cyanogenic glycosides is more prominent in people suffering from malnutrition and people for whom staple food has high amounts of cyanogenic, such as Cassava. ...
... The purpose of the final product (functional fraction, added ingredient or use as a cheaper source of protein) will dictate the technology to be used for detoxification. (Conn, 1979) (Bhatty and Cherdkiatgumchai, 1990 Table 3. Major edible plant containing cyanogenic glycosides (Cressey et al., 2013;Rezaul Haque and Howard Bradbury, 2002;Speijers, 1993 (Madhusudhan and Singh, 1985a) Flaxseed, ground Baking at 230 o C for 15-18 min to make muffins. ...
Flaxseed cake is a low value, a protein-rich by-product of flaxseed oil pressing companies. Flaxseed oil has been known as a rich source of omega-3 fatty acids and has been widely used. However, due to the presence of anti-nutritive compounds such as phytic acid, linatine, and cyanogenic glycosides, flaxseed cake that has a high protein content has limited food application. Cyanogenic compounds, particularly cyanogenic glycosides, can be degraded to toxic HCN upon ingestion. Therefore, the cake with a high content of fibre and protein with great nutritional potential has been underutilised and has some limited animal feed applications. Detoxification of the flax cake from cyanogenic content can, therefore, improve the market value of the protein and increase its food application. This review focuses on various available methods for detoxification of flax seed cake with emphasis on nutritional properties of the final product. The impact of various flaxseed cake detoxification methods on the protein is critically evaluated, discussing the options available toward increasing the food application value of this high protein product.
... In fact, the level of rhodanese in different tissues is higher in animals which, by ingesting a greater quantity of cyanide with their diet, need a greater detoxification efficiency. In particular, since cyanide occurs naturally as cyanogenic glycosides in a number of plants (e.g., sorghum, linseed, clovers, grasses, cassava and bamboo [15]), herbivores are more exposed to cyanide through food than carnivores and, subse- In the last twenty years, several studies have highlighted the involvement of TST in metabolic processes, as well as its relevance in various metabolic and non-metabolic diseases. This review underlines the structural aspects of this enzyme, which has represented and still represents an enzymatic structural model. ...
... Water proton NMR relaxation studies [53] and 35 Cl NMR relaxation studies [54] on eukaryotic Rhobov report that there are significant changes in the exposure to solvent or to anion binding for the two catalytic states ES and E. These results have been interpreted as due to important interdomain reorientation(s) between the two structural domains of the enzyme upon the catalytic cycle [54]. However, 15 N NMR relaxation studies together with essential dynamics studies on the prokaryotic TST from Azotobacter vinelandii (RhdA) [55,56] did not show large differences between the two forms indicating that only small conformational rearrangements, probably confined around the active site, occur between the ES and E form. However, all the structural studies on both eukaryotic and prokaryotic TST proteins with double domains are in agreement with an enhanced solvent accessibility in the E form. ...
Thiosulfate: cyanide sulfurtransferase (TST), also named rhodanese, is an enzyme widely distributed in both prokaryotes and eukaryotes, where it plays a relevant role in mitochondrial function. TST enzyme is involved in several biochemical processes such as: cyanide detoxification, the transport of sulfur and selenium in biologically available forms, the restoration of iron–sulfur clusters, redox system maintenance and the mitochondrial import of 5S rRNA. Recently, the relevance of TST in metabolic diseases, such as diabetes, has been highlighted, opening the way for research on important aspects of sulfur metabolism in diabetes. This review underlines the structural and functional characteristics of TST, describing the physiological role and biomedical and biotechnological applications of this essential enzyme.
... They are derived from amino acids and are stored in vacuoles as inactive glycosylated precursors. The thermal processing of beans has been found to reduce total hydrogen cyanide content by 54-82% (Cressey, et al., 2013). Cyanogenic glycosides are not toxic by themselves, but cyanide is, acting at the level of cytochrome oxidase, a powerful inhibitor of the respiratory chain (Valle, 2000). ...
... Cyanogenic glycosides are not toxic by themselves, but cyanide is, acting at the level of cytochrome oxidase, a powerful inhibitor of the respiratory chain (Valle, 2000). In addition, after enzymatic hydrolysis by endogenous βglucosidases they act as deterrents to feeding or oviposition (Shlichta, et al., 2014), and hydrogen cyanide is produced resulting in cyanide poisoning which causes rapid breathing, headache, dizziness and seizures, symptoms (Cressey, et al., 2013), ...
Legumes are one of the main sources of vegetable protein, and it has also been shown that, after consumption, beneficial effects can be obtained for human health, since they can help reduce blood glucose levels, as they are considered a low glycemic index food, promote bone health, and contain bioactive compounds with different biological activities such as hypotensive or hypocholesterolemic, among others. This group of foods are considered complete foods since they contain proteins, carbohydrates, minerals, vitamins, among other nutritional components; however, they also have antinutritional factors (ANF), which are defined as non-fibrous natural substances that can cause a negative effect on the nutritional value of some foods, as well as on health since they hinder or inhibit the assimilation of some nutrients. For this reason, it is of great importance to apply processing methods to reduce or eliminate the presence of these ANF in legumes.
... Cyanogenic glycosides release hydrogen cyanide, a potent respiratory inhibitor upon hydrolysis and are present in the range between 9 -178 mg kg -1 of linseed products. It is clear from observations of Cresseya et al. (2013) that products having linseed as an ingredient contain the highest concentration of total hydrocyanic acid (>50 mgkg -1 ). The minimum lethal dose of HCN taken orally is approximately 0.5-3.5 mg /kg body weight or 35 -245 mg for a 75 kg person (Shahidi and Wanasundara, 1997). ...
... Cyanogenic glycosides release hydrogen cyanide, a potent respiratory inhibitor upon hydrolysis and are present in the range between 9 -178 mg kg -1 of linseed products. It is clear from the observations of Cresseya et al. (2013) that products having linseed as an ingredient contain the highest concentration of total hydrocyanic acid (>50 mg kg -1 ). The minimum lethal dose of HCN taken orally is approximately 0.5-3.5 mg /kg body weight or 35 -245 mg for a 75 kg person (Shahidi and Wanasundara, 1997). ...
Linseed (Linum usitatissimum) is a highly nutritious oilseed with exceptionally high contents of α-linolenic acid (ALA), dietary fiber, good quality protein and phyto-estrogens. It is the richest known vegetable source of omega-3 fatty acid and various minerals. It also contains anti-nutritional factors like phenolics, tannins and cyanogenic glycosides that are known to inhibit the activity of digestive enzymes and interfere with availability of nutrients especially minerals like calcium and iron. Hence, an attempt was made to reduce anti-nutrients by different processes like soaking, roasting, fermentation etc. Lactic acid bacterial strains were isolated from linseed, screened and isolate LAB-3 was selected based on high titrable acid production (0.08%), desired sour-sweet taste and good flavor after fermentation. Probiotic cultures viz., Lactobacillus acidophilus, Bacillus mesentericus and Saccharomyces boulardii; wine yeast Saccharomyces ellipsoideus and lactic acid bacterial isolate LAB-3 were used in fermentation of linseed beverage. The quantity of anti-nutritional factors viz., total phenolics, tannins and cyanogenic glycosides were estimated. Significant reductions in total phenolics and tannins were observed in L. acidophilus and isolate LAB-3 treatments. Fermented beverage had 58% reduced phenolics and 66% reduced tannins compared to raw seed (control). This significant reduction in phenolics and tannins were observed with lactic acid bacteria than yeasts. The highest per cent reduction in cyanogenic glycosides was observed with L. acidophilus inoculation (66% followed by isolate LAB-3 (65%) and B. mesentericus (58%). The observed antinutritional reduction ability may be due to enzymes like linamarase and β-glucosidase production by tested microorganisms. Hence, this study leads to a conclusion that, microbial intervention can be exploited very conveniently to reduce anti-nutrients and to improve nutritional quality of linseed.
... In kernels, Aldrich, Carmel, Fritz, and Wood Colony varieties show the highest total cyanide content across all measured varieties (Table 5), similar to previous studies. 8,22,24,40,41 The higher levels of amygdalin generally corresponded with higher levels of prunasin and CN in the kernels. This trend was not apparent in the hulls as prunasin levels were frequently higher than amygdalin levels and were variety dependent (Table 6, Figure 4). ...
Almonds contain cyanogenic glycosides (CNGs), prunasin and amygdalin, which generate hydrogen cyanide upon hydrolysis. Different extraction and analytical methods are currently used to measure CNGs or cyanide (CN), necessitating distinct samples and can lead to inconsistent or incomparable results. To address this, we describe a method that uses ultrasonic-assisted sample extraction. Amygdalin and prunasin are measured directly in the extract, whereas CN is measured in the extract after derivatization with cysteine ethyl ester to form a cyano-S-ethyl-O-cysteine (CNCysEt) conjugate. The amygdalin, prunasin, and CNCysEt are quantified using the same UHPLC-(+ESI)MS/MS method. This new approach measured total CN in ten common almond kernel and hull varieties. The limit of quantitation ranged from 7.78 μg L–1 (amygdalin), 51.36 μg L–1 (prunasin), and 7.80 μg L–1 (CNCysEt; kernel) and 25.02 μg L–1 (CNCysEt; hull). This is the first time CNGs and CN levels are reported for almond hulls. Average total CN levels in hulls (<3 mg kg–1) were significantly lower than levels in kernels (<20 mg kg–1). Based on these findings, the hulls from California sweet almond varieties may be considered for use in human food products without additional processing to reduce CNG levels.
... Some legumes, such as pigeon peas, contain cyanogenic glycosides that release hydrogen cyanide, a toxic compound, upon enzymatic breakdown [70]. Fermentation with bacteria such as L. plantarum has been shown to degrade these cyanogenic glycosides into nontoxic substances [71]. ...
The escalating global demand for nutritious and sustainable food sources has heightened interest in microbial biotransformation in food, a process in which microorganisms chemically modify food components to enhance their functional properties and nutritional content. This review provides a comprehensive overview of recent advancements in microbial fermentation, focusing on its impact on food quality, nutritional enhancement , and public health. Emphasizing both traditional fermentation practices and modern biotechnological innovations, this review highlights how beneficial microorganisms transform raw food substrates into products with superior nutrient bioavailability and functional benefits. Key developments include the synthesis of bioactive compounds, reduction of anti-nutritional factors, and improvement of sensory attributes, all of which collectively contribute to disease prevention, gut health, and overall well-being. Additionally , this review addresses safety concerns and challenges in microbial fermentation, including microbiological hazards, chemical contaminants, and strategies for their management. It also explores the difficulties in scaling up these processes for industrial applications and discusses future directions for sustainable food production. By consolidating current knowledge and identifying emerging trends, this review provides a comprehensive resource for researchers, industry professionals, and policymakers, offering insights into leveraging microbial biotransformation to create nutritionally enriched and functionally enhanced food products.
... The IN-BA method was used to analyze CNcontent evaluating by comparison to a standard NaCN curve constructed using a series diluted concentration of 0.01, 0.04, 0.06, 0.08, 0.1, 0.15 and 0.2 mg/L, modified from a previously described method 54 . Briefly, samples were added into 50 ml tuber with 40 ml NaOH water solution (0.05 M), each sample was grinded, vortexed, sonicated twice on ice for 30 min and centrifuged at 20,000 rpm at 4°C for 20 min, and the supernatant were collected. ...
Larvae and adults of the Colorado potato beetle (Leptinotarsa decemlineata), a major pest of potato crops, display conspicuous coloration to advertise their toxicity to predators. However, the identity of the toxic compounds remains unclear. Here, we show that larvae and adults release toxic hydrogen cyanide (HCN) from the degradation of mandelonitrile and other cyano-compounds, which are produced by commensal bacteria. We isolate the bacterium Proteus vulgaris Ld01 from the insect’s gut, and show that it produces HCN and a mandelonitrile-producing cyanoglucoside, amygdalin. Knockout of a gene (hcnB) encoding putative hydrogen cyanide synthase impairs HCN production in P. vulgaris Ld01. Antibiotic treatment of larvae, to eliminate their commensal bacteria, leads to a substantial reduction of HCN emission in larvae and adults. HCN release by bacteria-deprived beetles can be restored by addition of mandelonitrile or by re-infection with P. vulgaris Ld01 (but not with its ∆hcnB1 or ∆hcnB2 mutants). Finally, we use dual-choice experiments to show that domestic chicks prefer to eat bacteria-deprived larvae over control larvae, larvae re-colonized with P. vulgaris Ld01, or mandelonitrile-injected larvae. Our work highlights the role of the beetle’s intestinal bacteria in the production of the cyanoglucoside amygdalin and its derived metabolites, including mandelonitrile and HCN, which protect the insect from predation.
... Some beans imported into Japan are known to contain cyanogenic compounds [3], and according to the Food Sanitation Act, their distribution and use are only permitted as raw bean paste materials. Therefore, in the sweetened bean paste manufacturing process, cyanogenic compounds contained in the beans as a raw material are considered to be a chemical hazard [4][5][6]. To demonstrate the efficacy of risk management measures through compliance with manufacturing standards, cyanogenic residues should be quantitatively determined at CCPs [2]. ...
To ensure food safety, food business operators must eliminate or reduce hazardous factors in manufacturing processes by implementing effective process controls. Since some beans are known to contain cyanogenic compounds, their distribution and use are permitted only as a raw bean paste material. Therefore, from the perspective of Hazard Analysis and Critical Control Points (HACCP), the purpose of this study is to demonstrate the validity of establishing CCPs and to determine the cyanogenic compounds in intermediate products for effectively managing hazardous substances in the manufacturing process. The previously reported method, post-column HPLC with fluorescence detection, was used for determine cyanogenic compounds in CCPs.
While free cyanide ions were only detected at CCP#1, cyanoglycoside analysis was crucial throughout the manufacturing process. Results indicated a decrease in cyanoglycoside concentration as manufacturing progressed, with levels below 10 ppm in the final product. Notably, cyanoglycosides decreased significantly during the shibukiri process (soaking, boiling, and discarding water). The concentration of cyanogenic compounds in raw beans were below the regulated 500 ppm, and the concentrations in the final product were below regulated 10 ppm. In conclusion, it was found that proposed method is very useful for HACCP management to monitor the decrease of cyanide compounds in the manufacturing process.
... Yet, when tissue damage occurs, facilitated by a digestive enzyme, they can produce a bioactive substance, particularly toxic cyanide (e.g., hydrogen cyanide, HCN) [32]. This process can result in symptoms associated with cyanide poisoning upon substantial ingestion [106]. The intake of HCN can induce intoxication and, in severe instances, may even lead to fatality when consumed in concentrated doses. ...
... The toxicity of cyanogenic glycosides arises from enzymatic degradation to produce hydrogen cyanide, which may result in acute cyanide, resulting in acute cyanide poisoning, including rapid respiration, a drop in blood pressure, a rapid pulse, headache, dizziness, vomiting, stomachache, diarrhea, mental confusion, stupor, blue discoloration of the skin due to lack of oxygen, and twitching and convulsions. In extreme cases human death may occur due to cyanide poisoning (Cressey et al., 2013). In addition, consuming food products with considerable amounts of cyanogenic glycosides is associated with health complications such as acute intoxication, chronic toxicity, neurological disorders, growth retardation, and goiter (Bolarinwa et al., 2016;Schrenk et al., 2019). ...
... Some legumes (e.g., pigeon peas) contain cyanogenic glycosides (4.5 to 5.5 mg/g) which are converted to the toxin hydrogen cyanide through the activity of endogenous enzymes. This may result in cyanide poisoning after consumption [205]. Fermentation by bacteria such as Lactiplantibacillus plantarum is capable of degrading cyanogenic glycosides to non-harmful substances [206]. ...
A rapidly growing population, resource scarcity, and the future sustainability of our food supply are among the major concerns of today’s food industry. The importance of resilient food crops that will sustain in the future is imperative, and legumes are ideal future food crops owing to their rich nutrient profile, cost-effective production and resource usage efficiency. Furthermore, they have the potential to meet the protein needs of the future. There are however several limitations associated with legumes in terms of their sensory, nutritional, and functional properties, which make them challenging for the food industry to use. In this review, these challenges are discussed in detail with particular reference to fermentation as a strategy for overcoming them. A major focus is on examining the potential application of fermentation for modifying techno-functional properties, such as foaming and emulsifying properties, solubility, and water and oil binding capacities of legume substrates. In many studies, fermentation has been demonstrated to enhance the techno-functional, sensory and nutritional attributes of various legume substrates. Future studies must focus on developing scalable fermentation processes to utilize the technology for improving the techno-functional and sensory properties of legume-based ingredients at industrial scale.
... CNGs, glycosides with α-hydroxynitrile, are composed of an aglycone with a sugar group attached (Bolarinwa et al. 2015). CNGs are potentially highly toxic substance, releasing hydrogen cyanide when hydrolyzed, although the compounds themselves are not toxic, and may lead to acute cyanide poisoning (Cressey et al. 2013). Another class of plant nitrogenous compounds is non-protein amino acids, which are important stores of nitrogen in plants. ...
With the widespread use of antibiotic drugs worldwide and the global increase in the number of immunodeficient patients, fungal infections have become a serious threat to global public health security. Moreover, the evolution of fungal resistance to existing antifungal drugs is on the rise. To address these issues, the development of new antifungal drugs or fungal inhibitors needs to be targeted urgently. Plant secondary metabolites are characterized by a wide variety of chemical structures, low price, high availability, high antimicrobial activity, and few side effects. Therefore, plant secondary metabolites may be important resources for the identification and development of novel antifungal drugs. However, there are few studies to summarize those contents. In this review, the antifungal modes of action of plant secondary metabolites toward different types of fungi and fungal infections are covered, as well as highlighting immunomodulatory effects on the human body. This review of the literature should lay the foundation for research into new antifungal drugs and the discovery of new targets.
Key points
• Immunocompromised patients who are infected the drug-resistant fungi are increasing.
• Plant secondary metabolites toward various fungal targets are covered.
• Plant secondary metabolites with immunomodulatory effect are verified in vivo.
... In this study, the contents of HCN in ratooning sorghum were greater than 800 mg/kg FW, significantly higher than the safety threshold (200 mg/kg FW). As one of the antinutritive, the CNglcs in ratooning sorghum increased its risk of poisoning when used as livestock feeds (Cressey et al., 2013). Therefore, the removal of CNglcs is the prerequisites for ratooning sorghum to be used as livestock feeds. ...
Introduction
Cyanogenic glycosides (CNglcs) are bioactive plant products involving in plant defense against herbivores by virtue of their abilities to release toxic hydrogen cyanide (HCN). Aspergillus niger has been shown to be effective in producing β-glucosidase, which could degrade CNglcs. However, whether A. niger could remove CNglcs under ensiling conditions is still unknown.
Methods
In this study, we first investigated the HCN contents in ratooning sorghums for two years, then the sorghums were ensiled with or without the addition of A. niger.
Results
Two years’ investigation indicated that the contents of HCN in fresh ratooning sorghum were larger than 801 mg/kg FW (fresh weight), which could not be reduced by silage fermentation under safety threshold (200 mg/kg FW). A. niger could produce β-glucosidase over a range of pH and temperature, which degraded the CNglcs and removed the hydrogen cyanide (HCN) at early days of ratooning sorghum fermentation. The addition of A. niger (2.56 × 10⁷ CFU/ml) altered the microbial community, increased bacterial diversity, improved the nutritive qualities, and reduced the HCN contents in ensiled ratooning sorghum lower than 100 mg/kg FW after 60 days of fermentation. Overall, the addition of 150 ml A. niger + 50 ml sterile water per 3 kg silage could efficiently remove CNglcs from ratooning sorghum silage.
Conclusion
In conclusion, A. niger could produce β-glucosidase which degraded the CNglcs during the early days of fermentation, benefiting the ensiling process and improving the utilization of ratooning sorghum.
... The quantity of CGs in different flax seed cultivars can vary from 0.74 to 1.60 g/Kg of cyanide (Russo and Reggiani 2014). Whole seed contains a low concentration of CGs; however, flours and foods with flaxseed content, such as bread, which can be frequently consumed, pose a greater risk as flax seed products contained a high concentration of total hydrocyanic acid (HCN) of >50 mg/kg in flax seed Cressey, Saunders, andGoodman (2013) (Kobaisy, Oomah, andMazza 1996;P. Wanasundara and Shahidi 1998). ...
Flaxseed consumption (Linum usitatissimum L.) has increased due to its potential health benefits, such as protection against inflammation, diabetes, cancer, and cardiovascular diseases. However, flaxseeds also contains various anti-nutritive and toxic compounds such as cyanogenic glycosides, and phytic acids etc. In this case, the long-term consumption of flaxseed may pose health risks due to these non-nutritional substances, which may be life threatening if consumed in high doses, although if appropriately utilized these may prevent/treat various diseases by preventing/inhibiting and or reversing the toxicity induced by other compounds. Therefore, it is necessary to remove or suppress the harmful and anti-nutritive effects of flaxseeds before these are utilized for large-scale as food for human consumption. Interestingly, the toxic compounds of flaxseed also undergoes biochemical detoxification in the body, transforming into less toxic or inactive forms like α-ketoglutarate cyanohydrin etc. However, such detoxification is also a challenge for the development, scalability, and real-time quantification of these bioactive substances. This review focuses on the health affecting composition of flaxseed, along with health benefits and potential toxicity of its components, detoxification methods and mechanisms with evidence supported by animal and human studies.
... The highest cyanide content within these product groups was 1.3 ppm, recorded in a tapioca chip product. The extensive processing of cassava to obtain tapioca removes most CNglc [14], and a low cyanide content has been reported for tapioca-based products previously [17,32]. ...
In 2009, Food Standards Australia New Zealand set a total cyanide content limit of 10 ppm for ready-to-eat cassava products to address food safety concerns about cyanogenic glucosides in cassava. This study surveys a range of cassava food products available in Melbourne, Australia, ten years after the implementation of these regulations. Of all the products tested, the mean cyanide content was greatest in ready-to-eat cassava chips (48.4 ppm), although imported ready-to-eat products had a higher mean cyanide content (95.9 ppm) than those manufactured in Australia (1.0 ppm). Cyanide was detected in frozen cassava products (grated mean = 12.9 ppm; whole root mean = 19.8 ppm), but was significantly reduced through processing according to packet instructions in both product types. Three methods were used to quantify total cyanide content: the evolved cyanide method, the picrate absorbance method and the picrate chart method, with satisfactory agreement between methods. The picrate absorbance and chart methods reported mean cyanide contents 13.7 ppm and 23.1 ppm higher, respectively, than the evolved cyanide method. Our results reaffirm the need for the ongoing testing of cassava food products, especially ready-to-eat products whose cyanide content will not be reduced before consumption.
... Cyanogenic compounds (CCs) occur in a wide range of plant species. The potential toxicity attributed to CCs is due to enzyme-mediated hydrogen cyanide (HCN) production, which may cause acute cyanide poisoning and participate in the pathogenesis of multiple chronic diseases [102]. It was estimated that from the almost 25 CCs currently known, a high proportion is derived from the edible part of almonds, sorghum, and bamboo shoots, providing a negative bitter taste [103]. ...
The search for waste minimization and the valorization of by-products are key to good management and improved sustainability in the food industry. The great production of almonds, based on their high nutritional value as food, especially almond kernels, generates tons of waste yearly. The remaining parts (skin, shell, hulls, etc.) are still little explored, even though they have been used as fuel by burning or as livestock feed. The interest in these by-products has been increasing, as they possess beneficial properties, caused by the presence of different bioactive compounds, and can be used as promising sources of new ingredients for the food, cosmetic and pharmaceutical industry. Additionally, the use of almond by-products is being increasingly applied for the fortification of already-existing food products, but there are some limitations, including the presence of allergens and mycotoxins that harden their applicability. This review focuses on the extraction technologies applied to the valorization of almond by-products for the development of new value-added products that would contribute to the reduction of environmental impact and an improvement in the sustainability and competitiveness of the almond industry.
... Cyanogenic glycosides occurrence in a broad range of plant. The toxicity of this compounds get up from enzymatic degradation to lead hydrogen cyanide, that severe poisoning (16). ...
Medicinal plants are still a chief portion of the medicine in advance countries, may be used to treatment the divers human disease through utilized various plants material. Therefore, the researcher focus on analysis the plants material by using high performance liquid chromatography HPLC technique. HPLC technique is sensitive and rapid technique, utilized to identification the qualification and quantification various constituents in traditional medicine plants. Plants constituents as alkaloids, phenols, saponins, tannins, anthocyanin, flavonoids, anthraquinones, cardiac glycosides, and cyanogenic glycosides. The present review chiefly focuses on the plants constituents' identification by HPLC for preparations diverse pharmaceutical products.
... Although the body can convert alpha linolenic acid into DHA and eicosapaentinoic acid, this process is not efficient [3]. Moreover, there have been concerns raised about the processing of flaxseed [90,91]. At present, the safe amount of ground flaxseed is not well known and caution is advised [91,92]. ...
Abstract Vegan diets – defined as the exclusion of all foods of animal origin from the diet- are becoming popular. In recent years, the prevalence of food allergy has also increased, and disproportionately affects children. When vegan diets and food allergy co-occur, this combination can be challenging and pose risks of nutritional deficiencies, particularly during childhood. In this paper, we aim to summarise the major concerns regarding vegan diets and food allergy, review the literature on this topic, and provide some suggestions for healthcare providers, particularly dietitians and nutritionists, who work with food allergic, vegan patients and their family. When working with this patient population, a regular and complete medical nutrition history, including screening for any possible nutritional deficiencies, is warranted. Likewise, the routine tracking of serum markers (especially iodine, iron, zinc, calcium, Vitamins B12, D, B2, and A, selected n-3 fatty acids and protein, which are more abundant in animal vs. plant foods) and symptoms of co-morbid diseases, including asthma, is important, as comorbid diseases may increase energy and nutrient requirements. For infants and children, anthropometry ought to be tracked longitudinally at regular intervals to identify any deviations from the child’s previous growth pattern, and to accommodate any increased requirements for growth and development. Correct diagnoses, education and allergy management must be disseminated to the family in a clear and appropriate manner. Children with allergy may have increased nutritional needs due to comorbidity. This is complicated by coincident food allergy and vegan diet as both impose diet restrictions (limiting sources of important nutrients, need for dietary variety and/or increased consumption due to reduced bioavaliability).
... As a result of the cyanide group, cyanogenic glycoside has a toxic effect by generating hydrogen cyanide through enzymatic degradation. Generally, overconsuming of cyanogenic plants causes symptoms associated with cyanide poisonings, such as rapid respiration, dizziness, headache, vomiting, stupor, and mental confusion (13). Indeed, the bacterial flora of the small intestine is capable of decomposing the linkage between sugar and aglycone by producing enzymes and consequently cause the release of hydrogen cyanide ended in severe liver toxicity (14). ...
Cyanogenic glycosides are defined as natural herbal toxins which are found in more than 2000 plant species and most of them consumed by humans. These nitrile-containing compounds do not present toxic effects in intact form while they produce toxic cyanide following enzymatic digestion. Therefore, over-consuming of these compounds can lead to cyanide poisoning. On the other hand, some cyanogenic compounds such as amygdalin and linamarin have therapeutic effects and they have been used as a traditional medicine to treat several diseases such as cancer. It seems that the biological properties of these compounds such as bioavailability, solubility, and stability elevate by glycosylation which causes the increased anti-tumor activity of compounds. However, a major challenge in its various applications such as anti-cancer drugs is cyanide poisoning which has been reported in some patients. Interestingly, different approaches of targeted therapy have been applied to elevate these compounds' pharmaceutical properties in targeting cancer cells, like suicide gene therapy, antibody-directed enzyme prodrug therapy (ADEPT), and nanoporous imprinted polymers (nanoMIPs). In this review, we have focused on the challenges of cyanide toxicity raised from amygdalin and linamarin and on various approaches to their targeted therapy in cancer treatment as well.
... Biotic and abiotic metabolites can contaminate crops and plant-based foods; therefore, toxins must be examined [24]. Cyanogenic glycosides occur in a wide range of food plant species, such as cassava root, apples, lima beans, passion fruit, and almonds [25]. Almonds contain amygdalin as a cyanogenic glycoside (a secondary metabolite) [26]. ...
Prunus serotine seed, was processed to produce a defatted flour (71.07 ± 2.10% yield) without hydrocyanic acid. The total protein was 50.94 ± 0.64%. According to sensory evaluation of cookies with P. serotine flour, the highest score in overall impression (6.31) was at 50% flour substitution. Its nutritional composition stood out for its protein and fiber contents 12.50% and 0.93%, respectively. Protein concentrate (PsPC) was elaborated (81.44 ± 7.74% protein) from defatted flour. Emulsifying properties of PsPC were studied in emulsions at different mass fractions; ϕ = 0.002, 0.02, 0.1, 0.2, and 0.4 through physicochemical analysis and compared with whey protein concentrate (WPC). Particle size in emulsions increased, as did oil content, and results were reflected in microscope photographs. PsPC at ϕ 0.02 showed positive results along the study, reflected in the microphotograph and emulsifying stability index (ESI) test (117.50 min). At ϕ 0.4, the lowest ESI (29.34 min), but the maximum emulsifying activity index (EAI) value (0.029 m²/g) was reached. WPC had an EAI value higher than PsPC at ϕ ≥ 0.2, but its ESI were always lower in all mass fraction values. PsPC can compete with emulsifiers as WPC and help stabilize emulsions.
... Previous studies on mycotoxins revealed that these compounds are hazardous to animals and humans. Generally, it has been reported that CGs as well as mycotoxins occur naturally in flora and organisms (fungi) as a result of biosynthesis, with their prevalence being quantifiable in many agricultural products, such as cassava, apples, spinach, apricots, cherries, peaches, plums, quinces, almonds, sorghum, lima beans, corn, yams, chickpeas, cashews and kirsch [15,16]. Although some microorganisms and plants synthesise these compounds for their survival when exposed to harsh environmental conditions, their cumulative production can contribute to ecological disturbances. ...
Cyanogens and mycotoxins are vital in protecting flora against predation. Nevertheless,
their increased concentrations and by-products in agricultural soil could result in produce
contamination and decreased crop yield and soil productivity. When exposed to
unsuitable weather conditions, agricultural produce such as cassava is susceptible to
bacterial and fungal attack, culminating in spoilage, particularly in arid and semi-arid
regions, and contributing to cyanogen and mycotoxins loading of the arable land. The
movement of cyanogen including mycotoxins in such soil can result in sub-surface and/
or groundwater contamination, thus deteriorating the soil’s environmental health and
negatively affecting wildlife and humans. Persistent cyanogen and mycotoxins loading
into agricultural soil changes its physico-chemical characteristics and biotic parameters.
These contaminants and their biodegradation by-products can be dispersed from soil’s
surface and sub-surface to groundwater systems by permeation and percolation through
the upper soil layer into underground water reservoirs, which can result in their exposure
to humans and wildlife. Thus, an assessment and monitoring of cyanogen and mycotoxins
loading impacts on arable land and groundwater in communities with minimal
resources should be done. Overall, these toxicants impacts on agricultural soil’s biotic
community, affect soil’s aggregates, functionality and lead to the soil’s low productivity,
cross-contamination of fresh agricultural produce.
... The cassava is now largely detoxified by the prolonged soaking in the running water. All these activities contribute to the release of cyanogenic glycosides from enzymatic degradation following maceration to produce hydrogen cyanide, which may result in acute cyanide poisoning [10]. Cyanide binds and inactivate several enzymes, particularly those with iron in the ferric (Fe 3+ ) state and cobalt [11]. ...
Cyanide pollution of aquatic environment has become a great concern in Nigeria because of the increase in cassava cultivation. In Nigeria, cassava processing milling plants are usually situated around streams or rivers such that the waste from each stages of processing easily find their way into these water bodies as effluents and waste waters. Extracellular rhodanese of Klebsiella edwardsii isolated from Atutulala stream, Modakeke, where cassava is being processed, was assessed for its bioremediation potential. Cyanide concentration of the stream was analysed for six months. Four bacterial isolates were screened for their ability to degrade free cyanide and the best strain was further screened for rhodanese producing ability. The enzyme was purified by 85% ammonium sulphate precipitation and diethyl aminoethyl-cellulose ion-exchange chromatography. The pure enzyme had a specific activity of 0.0473 Rhodanese Unit mg-1 with a purification fold of 4.56 and a percentage yield of 30.30%. The enzyme demonstrated a broad pH range but the optimum pH was at 6.0 while the optimum temperature was 60°C. The bioremediation potential of the enzyme was assessed under various conditions such as the field pH and temperature as well as optimum pH and temperature using the cyanide contaminated water as substrate source in a typical assay protocol. The enzyme was able to convert 1.6481 μmol of cyanide to thiocyanate in the water sample at optimum pH and temperature of the enzyme. It could be concluded from the study that at optimum pH and temperature, rhodanese exhibited remediation activity in cyanide contaminated aquatic ecosystems and thus, can be used for its restoration.
... HCN content of raw flaxseed used in this study was 218 mg/kg. Cressey et al. [23] analyzed 100 retail foods including cassava, bamboo shoots, almonds and its products, pome fruit products, flaxseed, stone fruit products, lima beans, taro leaves, passion fruit, spinach and canned stuffed vine leaves for the presence of total HCN and reported that flaxseed contained the highest concentrations [12] reported that extrusion can remove HCN in flaxseed up to 91.62% at optimum conditions. ...
Flaxseeds were roasted at 1150 W/m² radiation intensity with short and medium wave infrared (IR) emitters for specific durations, which provided good visual and sensory quality. The effects of IR roasting on color properties, hydrogen cyanide (HCN) content, tocopherols and fatty acid composition of the flaxseed and flaxseed oil were investigated. Further, flaxseeds were stored for 6 months and free fatty acid content and peroxide values were followed at 1-month intervals to understand the effect of IR treatment on hydrolytic and oxidative stability. HCN content of the flaxseeds was reduced up to 59% with IR roasting. Tocopherol content of the IR roasted flaxseed oil was higher than that of the control. No notable variation was observed in fatty acid composition with regard to IR treatment. Free fatty acid content of IR roasted flaxseeds did not increase during storage, while peroxide value of the seeds significantly increased up to 95 mEq O2/kg oil.
... To minimize risks for human health, the World Health Organization stated a safe level of cyanide content of 1 mg 100 g −1 for cassava flour (Haque and Bradbury 2002). When comparing the average contents of hydrocyanic acid (as an equivalent of total GC content) in cassava (average 21 mg kg −1 ) to those in whole linseeds or linseed flour (average 127 mg kg −1 ; Cressey et al. 2013), the contents in linseed products exceed the ones in cassava flour sixfold and seem high. However, given that cassava is a staple food and usually consumed in large quantities, the daily intake of about 2 tbs of linseed, according to the recommendation of BfR (German Federal Institute for Risk Assessment) (2006) may bear only minor health risks for humans (Ganorkar and Jain 2013). ...
Linseed contains substantial amounts of desired ingredients, such as omega-3 fatty acids (α-linolenic acid) and antioxidants, as well as undesired ingredients such as cyanogenic glycosides and cadmium. This paper presents and discusses the abiotic factors which influence quality and yield of linseed seeds in organic cropping systems. In temperate climates, conventional farmers can harvest more than 2.0 t seed ha−1, with oil contents ranging from 35 to 44 %. Organic trials usually had lower yields with up to approximately 1.8 t seed ha−1 in temperate, continental, and Mediterranean conditions. Cool climatic conditions in temperate regions lead to high shares (>60 %) of omega-3 fatty acids related to total oil content in organic farming as well as in conventional farming. Linseed achieved maximum yields of seeds and omega-3 fatty acids with a fertilization level of less than approximately 110 kg nitrogen ha−1. High levels of nitrogen fertilization did not benefit the content of omega-3 fatty acids; increasing the nitrogen fertilization from 52 to 260 kg ha−1 reduced the content of α-linolenic acid by 7.25 % in a trial. The content of cyanogenic compounds turned out to be positively correlated with the protein content of the seeds and the nitrogen fertilization; therefore, the usually moderate level of nitrogen supply in organic crop rotations could keep the content of cyanogenic glycosides on a comparatively low level, compared to cropping systems with higher nitrogen levels. Linseed is a hyper-accumulator of cadmium; the total cadmium content in the seeds is determined by the cadmium content of the soil and the linseed variety. Generally, the choice of linseed variety influences the quality of the seed, and respective varieties must be chosen to improve product quality. Harvest, post-harvest, and processing conditions additionally affect seed and oil quality. Heating can reduce the unwanted cyanogenic glycosides, but it also reduces the content of desired anti-oxidants and of omega-3 fatty acids.
All in all, low overall nitrogen levels in organic cropping systems may offer the option to produce linseed seeds and oil with high levels of omega-3 fatty acid and low cyanogenic glycosides, with yields similar to conventional farming. In organic farming systems, the risk of elevated cadmium contents in linseed is low as synthetic P fertilizers are prohibited and raw phosphates are rarely used, thus minimizing the input of cadmium via fertilizers. As high product quality can be maintained or even improved by organic farming practices, linseed is suitable as an oil crop in organic farming that allows diversification of the crop rotation.
... It is a potent cytotoxic agent that kills the cell by inhibiting cytochrome oxidase of the mitochondrial electron transport chain. Cyanide poisoning occurs when a living organism is exposed to a compound that produces cyanide ions (CN ) in aqueous solution (Peter et al., 2013). ...
Rhodanese from the cytosolic fraction of the hepatopancreas of garden snail, Limicolaria flammea was purified by 70% ammonium sulphate precipitation, Reactive Blue-2 Agarose affinity chromatography and CM-Sephadex C-25 ion-exchange chromatography. The pure enzyme had a specific activity of 4.57 µmol of thiocyanate formed per milligram of protein with a purification fold of 4.20 and a percentage yield of 19.73%. The native molecular weight was 33.1 kDa, while the subunit molecular weight of the enzyme was estimated to be 32.8 kDa. The K of m rhodanese from the hepatopancreas of Limicolaria flammea for sodium thiolsulphate (Na S O) and potassium 2 2 3 cyanide (KCN) were 12.3 mM and 9.1 mM respectively, while their V were 10.5 RU/ml/min and 7.4 max RU/ml/min respectively. The substrate specificity study showed the percentage utilization of the various substrates to be: 2-mercaptoethanol (2-MCPE) (57.8%), ammonium persulphate ((NH) S O) (37.6%), 4 2 2 8 ammonium sulphate ((NH) SO) (46.8%) and Sodium metabisulphite (Na S O) (48.1%). The K of rhodanese 4 2 4 2 2 5 m for the sulphur donor substrates were 13.3 mM, 15.4 mM, 15.9 mM and 13.5 mM respectively in the same order as above. The optimum temperature was 50°C at a pH of 8.0 and the activation energy values were 19.618 kcal/mol and 76.834 kcal/mol. The heat stability result showed the enzyme to be stable up to 50°C. The inhibition study on the enzyme by salts (BaCl , CaCl , CoCl , HgCl MgCl MnCl , NiCl and ZnCl) showed no 2 2 2 2, 2, 2 2 2 significant effect. In summary, this study showed the presence of rhodanese activity in hepatopancreas of garden snail, Limicolaria flammea. The presence of rhodanese in the hepatopancreas of Limicolaria flammea suggests that the enzyme may possess functional cyanide detoxification mechanism necessary for the survival of the animal in the environment. ABSTRACT 289
... The product was found to contain the highest level of total cyanide (220 mg/kg) in a set of 15 different linseed products purchased from the German market in May 2012 (total cyanide: mean 145 mg/kg, median 131 mg/kg, minimum 98 mg/kg). The distribution of the cyanide levels found in these products was comparable to that found in an investigation of the German food control authority in Sigmaringen in 2009 (mean 154 mg/g, range 80-300 mg/kg, n = 38, CVUA Sigmaringen 2009) and to that of a recent investigation from New Zealand (mean 127 mg/g, range 91-178 mg/kg, n = 5, Cressey et al. 2013). To assure the mechanical destruction of the linseed grains, the study meal of 30.9 g (corresponding to a dose of 6.8 mg cyanide) was ground up in an analysis mill (type A10 with star-shaped cutter A13, 20,000 rpm, IKA Labortechnik, Staufen, Germany) directly before consumption; chewing the linseed would by far not be as effective with regard to destruction. ...
The acute toxicity of cyanide is determined by its peak levels reached in the body. Compared to the ingestion of free cyanide, lower peak levels may be expected after consumption of foods containing cyanogenic glycosides with the same equivalent dose of cyanide. This is due to possible delayed and/or incomplete release of cyanide from the cyanogenic glycosides depending on many factors. Data on bioavailability of cyanide after consumption of foods containing high levels of cyanogenic glycosides as presented herein were necessary to allow a meaningful risk assessment for these foods. A crossover study was carried out in 12 healthy adults who consumed persipan paste (equivalent total cyanide: 68 mg/kg), linseed (220 mg/kg), bitter apricot kernels (about 3250 mg/kg), and fresh cassava roots (76–150 mg/kg), with each “meal” containing equivalents of 6.8 mg cyanide. Cyanide levels were determined in whole blood using a GC–MS method with K¹³C¹⁵N as internal standard. Mean levels of cyanide at the different time points were highest after consumption of cassava (15.4 µM, after 37.5 min) and bitter apricot kernels (14.3 µM, after 20 min), followed by linseed (5.7 µM, after 40 min) and 100 g persipan (1.3 µM, after 105 min). The double dose of 13.6 mg cyanide eaten with 200 g persipan paste resulted in a mean peak level of 2.9 µM (after 150 min). An acute reference dose of 0.075 mg/kg body weight was derived being valid for a single application/meal of cyanides or hydrocyanic acid as well as of unprocessed foods with cyanogenic glycosides also containing the accompanying intact β-glucosidase. For some of these foods, this approach may be overly conservative due to delayed release of cyanide, as demonstrated for linseed. In case of missing or inactivated β-glucosidase, the hazard potential is much lower.
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The online version of this article (doi:10.1007/s00204-015-1479-8) contains supplementary material, which is available to authorized users.
Abstract The addition of linseed (Linum usitatissimum Linn) in the diet, as a functional food, has increased over the years. However, it possesses cyanogenic glycosides. This study aimed to quantify and compare cyanide concentration in whole seed and bran of brown and golden types to establish a safe limit of intake. Three commercial labels, from brown and golden whole seed types (Ab, Ag, Bb, Bg, Cb and Cg), and six commercial labels of brown and golden bran (1b, 2g, 3g, 4b, 5g, and 6b), were selected, totalizing twelve samples. Total cyanide concentration was quantified by a colorimetric method employing alkaline picrate, after acid hydrolysis. The whole seed cyanide values were between 348.4 and 473.20 µg/g and the bran cyanide values were between 459.53 and 639.35 μg/g. The analyzed bran presented increased cyanide concentrations than the whole seeds with no differences between brown and golden types. Food able to produce cyanide less than 90 µg/kg body weight, daily, is considered secure for consumption. Considering this limit and analyzed samples, it is safe to eat approximately two tablespoons of seeds or one tablespoon of bran. These results point out the importance of cyanide amount daily intake information to be in linseed packaging, to ensure secure consumption.
Glucosinolates (GSLs) and cyanogenic glycosides (CGs) fulfil functions in plant defence and have been reported to be anticancer agents. Generally, GSL-containing plants do not produce CG, and vice versa, CG-containing plants do not synthesise GSLs. However, the production of both GSL and CG compounds was observed in Carica papaya. Additionally, several studies found both GSL glucotropaeolin and CG prunasin in papaya leaves. The advancement of genome technologies can be explored to elucidate the gene functions and other molecular discoveries in plants that might relate to GSLs and CGs. This review aims to discuss the complex interplay of the rare events whereby these two compounds (GSL and CG) co-occur in a bifurcation pathway in papaya. To our knowledge, this is the first review that highlights novel GSL and CG genes in papaya. Furthermore, species-specific pathways in papaya are also discussed and comprehensively described. The transcription factors involved in regulating GSL and CG biosynthesis pathways are also discussed, accompanied by relevant bioinformatic approaches that can help discover potential regulatory genes that control the production of prunasin and glucotropaeolin in papaya.
A novel organic probe (R) possessing multiple binding sites has rationally been designed, synthesized and characterized using NMR and mass spectral techniques. The probe R displays an excellent selective and sensitive response to CN– and SO32– ions over other anions. In aq. DMSO solution, R exhibits dual emission (463 and 590 nm) upon interaction with CN– ion, which is ascribed to the deprotonation of the N-H group of the probe. Upon addition of SO32– ion, the enhancement of fluorescence for R at 478 nm is attributed to the formation of 1:1 adduct between R and SO32– ion by the nucleophilic addition of SO32– to C-atom of the ring C=CH moiety. The fluorescence responses of R toward CN– and SO32– ions are pH independent in the 5 – 9 range. Limits of detection down to 28 and 3.7 nM were determined for CN– and SO32– quantitation, respectively. Theoretical calculations (DFT and TDDFT) are applied to interpret the absorption and dissimilar emission behaviour of the probe and its adduct with CN– and SO32– ions. The CN– induced dual fluorescence in R may be due to relaxation of the excited state to two different ground states.
Plants and plant products are used in food and medicine for thousands of years ago. It was thought that natural means safe, but this is not always the case as many plants or plant constituents are toxic or even poisonous especially those containing cardiac, cyanogenic, and thio-glycosides and certain types of alkaloids. Toxic natural products may cause hepatotoxicity, neurotoxicity, gastrointestinal toxicity, renal toxicity, and cytotoxicity. Analysis of toxic plants and plant constituents is facing a great challenge because of their different chemical and physicochemical properties. Novel extraction techniques have been proposed such as ultrasonic-assisted extraction, microwave-assisted extraction, supercritical fluid extraction, and accelerated solvent extraction. In this chapter, we will have an overview of some of the toxic plants and phytochemicals as well as the methods for their qualitative and quantitative analysis.
Cyanide is a toxic substance that can be lethal to humans and is present in nature in several superior plants, called cyanogenic plants, with the capacity to generate significant amounts of cyanide (CN) from the cyanogenic glycosides (GCs) present in a natural state. Among the most important GCs are linamarin, lotraustralin, dhurrin and amygdalin. Cassava, sorghum, almonds, apricots, peaches, apples, cherries, alfalfa, bamboo, among others, are examples of these plants. The potential to generate CN varies with each plant. This paper reviews the literature related to the amounts of cyanide produced by these plants, their effects on humans, as well as their toxicological implications.
An ultra-high-performance liquid chromatography-triple quadrupole tandem mass spectrometry (UHPLC-QqQ-MS/MS) method was established and validated for the simultaneous quantification of eight cyanogenic glucosides (CNGs) in agri-food. The eight CNGs were linamarin, lotaustralin, linustatin, neolinustatin, taxiphyllin, amygdalin, dhurrin and prunasin. CNGs were extracted with aqueous methanol and cleaned via solid-phase extraction. Analytes were separated with a C18 column via gradient elution. MS/MS analysis was performed with electrospray ionisation in positive mode. Quantification was performed in multiple reaction monitoring mode. Satisfactory validation results were obtained in terms of linearity, sensitivity, precision and accuracy, matrix effect and stability. The method was applied in typical cyanogenic agri-food. CNGs in cassava, linseed, bamboo, sorghum, apricot, almond and lima bean were analyzed.
The consumption of medicinal plants has notably increased over the past two decades. People consider herbal products as safe because of their natural origin, without taking into consideration whether these plants contain a toxic principle. This represents a serious health problem. A bibliographic search was carried out using published scientific material on native plants from Mexico, Central America, and the Caribbean, which describe the ethnobotanical and toxicological information of medicinal plants empirically considered to be toxic. A total of 216 medicinal plants belonging to 77 families have been reported as toxic. Of these plants, 76 had been studied, and 140 plants lacked studies regarding their toxicological effects. The toxicity of 16 plants species has been reported in clinical cases, particularly in children. From these plants, deaths have been reported with the consumption of Chenopodium ambrosioides , Argemone mexicana , and Thevetia peruviana . In most of the cases, the principle of the plant responsible for the toxicity is unknown. There is limited information about the toxicity of medicinal plants used in Mexico, Central America, and the Caribbean. More toxicological studies are necessary to contribute information about the safe use of the medicinal plants cited in this review.
The functional adaptive changes in cyanide detoxification in giant panda appear to be response to dietary transition from typical carnivore to herbivorous bear. We tested the absorption of cyanide contained in bamboo/bamboo shoots with a feeding trial in 20 adult giant pandas. We determined total cyanide content in bamboo shoots and giant panda’s feces, levels of urinary thiocyanate and tissue rhodanese activity using color reactions with a spectrophotometer. Rhodanese expression in liver and kidney at transcription and translation levels were measured using real-time RT-PCR and immunohistochemistry, respectively. We compared differences of rhodanese activity and gene expressions among giant panda, rabbit (herbivore) and cat (carnivore), and between newborn and adult giant pandas. Bamboo shoots contained 3.2 mg/kg of cyanide and giant pandas absorbed more than 65% of cyanide. However, approximately 80% of absorbed cyanide was metabolized to less toxic thiocyanate that was discharged in urine. Rhodanese expression and activity in liver and kidney of giant panda were significantly higher than in cat, but lower than in rabbit (all P < 0.05). Levels in adult pandas were higher than that in newborn cub. Phylogenetic analysis of both nucleotide and amino acid sequences of the rhodanese gene supported a closer relationship of giant panda with carnivores than with herbivores.
Soybean, canola, camelina and flaxseed co-products from the oilseed industry are used to formulate pig and poultry feeds. However, these co-products contain various anti-nutritional factors (ANF). The major ANF in soybean and potentially co-products is trypsin inhibitor (TI). Pigs and poultry can tolerate TI levels up to 3.00 and 4.00 TIU/mg in the diet, respectively. Solvent-extracted soybean meal has low TI activity (<14.0 TIU/mg); most TI is destroyed during the desolventising-toasting stage of oil extraction. Thus, inclusion of soybean meal in diets for pigs and poultry does not affect feed intake and nutrient utilization. However, soybean or expeller-pressed soybean co-products can contain considerable amounts of TI (>50.0 TIU/mg), implying that the raw soybean or expeller-pressed soybean co-products should be sufficiently heated to inactivate most of the TI before feeding. The major ANF in canola co-products are glucosinolates. Poultry and pigs can tolerate up to 2.00 and 2.50 μmol/g of glucosinolates in their diets. Total glucosinolate content in most canola co-products is moderate ( < 10 μmol/g). Thus, while co-products from modern canola cultivars do not affect feed intake, dietary inclusion of original canola co-products (with total glucosinolate content of ≤35 μmol/g) reduced feed intake of grow-finish pigs by 80 g/day and of broiler chickens in the starter phase by 4 g/day. Glucosinolates and TI are the major ANF in camelina co-products. In camelina co-products, total glucosinolate content ranged from 34.4 to 36.3 μmol/g and TI activity from 12 to 28 TIU/mg. Camelina co-products are not solvent-extracted and thus have high TI activity. Dietary inclusion of camelina co-products reduced feed intake of broiler chickens in the starter phase by 3.4 g/day. Cynogenic glucosides are the major ANF in flaxseed co-products. Flaxseed meal contained 127 mg cynogenic glucoside/kg. Dietary inclusion of flaxseed meal reduced feed intake by poultry by 3.4 g/day. In conclusion, soybean, canola, camelina and flaxseed co-products contain various ANF that reduce feed intake by pigs and poultry.
An activity for hydrogen cyanide detection in bitter seeds is presented. The procedure is based on the absorption of hydrogen cyanide (HCN) from a mixture of chopped seeds into a ninhydrin or tetramminecopper(II) complex solution followed by their reaction. A qualitative experiment is proposed in order to demonstrate the presence of HCN in bitter seeds and to visualize metal-cyanide reduction and formation of an interesting mixed valence copper amino-cyanide complex: Cu3(NH3)4(CN)4. © 2016 The American Chemical Society and Division of Chemical Education, Inc.
AimsCyanogenic glycosides are phytotoxic secondary metabolites produced by some crop plants. The aim of this study was to identify Lactic Acid Bacteria (LAB) capable of catabolizing amygdalin, a model cyanogenic glycoside, for use in the biodetoxification of amygdalin-containing foods and feeds.Methods and ResultsAmygdalin-catabolizing lactobacilli were characterized using a combination of cultivation-dependent and molecular assays. Lactobacillus paraplantarum and Lactobacillus plantarum grew robustly on amygdalin (Amg+), while other LAB species typically failed to catabolize amygdalin (Amg−). Interestingly, high concentrations of amygdalin and two of its metabolic derivatives (mandelonitrile and benzaldehyde) inhibited the growth of L. plantarum RENO 0093. The differential regulation of genes tentatively involved in cyanohydrin metabolism illustrated that the metabolism of amygdalin- and glucose-grown cultures also differed significantly.Conclusions
Amygdalin fermentation was a relatively uncommon phenotype among the LAB and generally limited to strains from the L. plantarum group. Phenotype microarrays (PM) enabled strain-level discrimination between closely-related strains within a species and suggested that phenotypic differences might affect niche specialization.Significance and Impact of the StudyAmygdalin-degrading lactobacilli with practical application in the biodetoxification of amygdalin were characterized. These strains show potential for use as starter cultures to improve the safety of foods and feeds.This article is protected by copyright. All rights reserved.
Cassava roots, a major food in Africa, contain cyanogenic glucosides that may cause toxic effects. Malawian women farmers
considered fields of seemingly similar cassava plants to be mixes of both ‘cool’ and ‘bitter’ cultivars. They regard roots
from ‘cool’ cultivars as non-toxic. Roots of ‘bitter’ were considered to require extensive traditional processing done by
women to be safe for consumption. But curiously, these women farmers preferred ‘bitter’ cultivars since toxicity confers protection
against theft, which was a serious threat to the food security of their families. We studied how well these farmers comprehend
the effects of genetic variations in cassava when dealing with cyanogenesis in this complex system. Using molecular markers
we show that most plants farmers identified as belonging to a particular named cultivar had a genotype typical of that cultivar.
Farmers' ethno-classification into ‘cool’ and ‘bitter’ cultivars corresponded to a genetic sub-division of the typical genotypes
of the most common cultivars, with four-fold higher cyanogenic glucoside levels in the bitter cultivars. Examining morphology,
farmers distinguished genotypes better than did the investigators when using a standard botanical key. Undoubtedly, these
women farmers grasp sufficiently the genetic diversity of cassava with regard to cyanogenesis to simultaneously benefit from
it and avoid its dangers. Consequently, acyanogenic cassava – the breeding of which is an announced good of some cassava genetic
improvement programmes – is not a priority to these farmers. Advances in molecular genetics can help improve food supply in
Africa by rapid micropropagation, marker assisted breeding and introduction of transgenic varieties, but can also help to
elucidate tropical small-scale farmers' needs and skills.
Cassava (Manihot esculenta Crantz) is a widely consumed food in the tropics that naturally contains cyanogenic glycosides (cyanogens, mainly composed of linamarin, acetone cyanohydrin, and hydrocyanic acid). If cassava is not adequately processed to reduce the level of cyanogens prior to consumption, these compounds can lead to the formation of hydrocyanic acid in the gut. Exposure to hydrocyanic acid can cause symptoms ranging from vomiting and abdominal pain to coma and death. In 2008, a survey of ready-to-eat (RTE) cassava-based snack foods was undertaken to determine levels of cyanogens measured as total hydrocyanic acid. This survey was undertaken in response to the New South Wales Food Authority being alerted to the detection of elevated levels of cyanogens in an RTE cassava-based snack food. This survey took 374 samples of RTE cassava chips available in the Australian marketplace. Significant variation in the levels of total hydrocyanic acid were observed in the 317 samples testing positive for cyanogens, with levels ranging from 13 to 165 mg of HCN equivalents per kg (mean value, 64.2 mg of HCN eq/kg for positive samples). The results from this survey serve as a timely warning for manufacturers of RTE cassava chips and other cassava-based snack foods to ensure there is tight control over the levels of cyanogens in the cassava ingredient. Evidence from this survey contributed to an amendment to the Australia New Zealand Food Standards Code, which now prescribes a maximum level for hydrocyanic acid in RTE cassava chips of 10 mg of HCN eq/kg, which aligns with the Codex Alimentarius Commission international standard for edible cassava flour.
A reference method (higher accuracy) and a routine method (higher throughput) were developed for the extraction of cyanogenic glycosides from flaxseed. Conditions of (essentially) complete extraction were identified by comparing grinding methods and extraction solvent composition, and optimizing solvent-to-meal ratio, extraction time, and repeat extraction. The reference extraction method consists of sample grinding using a high-speed impact plus sieving mill at 18 000 rpm with a 1.0 mm sieve coupled with triple-pooled extraction in a sonicating water bath (40 degrees C, 30 min) using 75% methanol. The routine method differs by the use of a coffee mill to grind samples and a single extraction. The 70 and 80% methanol solutions were equal and superior to other combinations from 50 to 100% aqueous ethanol or methanol. The extraction efficiencies of the routine method (relative to the reference method) was 87.9 +/- 2.0% SD (linustatin) and 87.6 +/- 1.9% SD (neolinustatin) using four composite samples that were generated from seeds of multiple cultivars over two crop years and locations across Western Canada. Ground flaxseed was stable after storage at room temperature, refrigeration, or freezing for up to 7 days, and frozen for at least 2 weeks but less than 2 months. Extracts were stable for up to 1 week at room temperature and at least 2 weeks when refrigerated or frozen.
The relationship between the levels of cyanogenic compounds (amygdalin and prunasin) in kernels, leaves, and roots of 5 sweet-, 5 slightly bitter-, and 5 bitter-kernelled almond trees was determined. Variability was observed among the genotypes for these compounds. Prunasin was found only in the vegetative part (roots and leaves) for all genotypes tested. Amygdalin was detected only in the kernels, mainly in bitter genotypes. In general, bitter-kernelled genotypes had higher levels of prunasin in their roots than nonbitter ones, but the correlation between cyanogenic compounds in the different parts of plants was not high. While prunasin seems to be present in most almond roots (with a variable concentration) only bitter-kernelled genotypes are able to transform it into amygdalin in the kernel. Breeding for prunasin-based resistance to the buprestid beetle Capnodis tenebrionis L. is discussed.
The development of well-characterized rapid methodology for the extraction and gas chromatographic analysis of the cyanogenic glycosides linustatin and neolinustatin from flaxseed (Linum usitatissimum L.) is reported. Two quantitation methods using phenyl-beta-D-glucopyranoside as an internal standard are described: direct quantitation using linustatin and neolinustatin external standard curves [standard curve slope variabilities of 2.6 and 5.7% relative standard deviation (RSD), respectively, over 7 days] or by use of methyl-alpha-D-glucopyranoside as a surrogate external standard, with conversion factors to convert to linustatin and neolinustatin concentration [1.109 +/- 0.015 (SD) mg linustatin/mg methyl-alpha-D-glucopyranoside and 1.180 +/-0.067 (SD) mg neolinustatin/mg methyl-alpha-D-glucopyranoside]. The former method is direct, thereby contributing less uncertainty to the method, and the latter adds a small degree of uncertainty coupled with considerable cost savings. Limits of detection for all standards were in the low- to sub-nanogram level and were 10-100 times lower than the lower limit of quantitation (LOQ). Repeatability precision was performed on 2 separate days at the lower and upper LOQs, with the RSD in peak response being 1% or lower in all cases. Extraction methods were evaluated for their ability to extract linustatin and neolinustatin from flaxseed using several combinations of aqueous ethanol, and recoveries were determined against the highest yielding method. Recoveries were as low as 82%, indicating that optimized extraction methodology is critical for the accuracy of results.
As a means of evaluating cyanogenic glycoside content, cyanide was determined in apple, cherry, almond, and peach seeds. Sample preparation involved enzymatic hydrolysis and collection of hydrogen cyanide in strong base. For analysis, cyanide was converted to ammonium by addition of excess KMnO4 followed by treatment with H2SO4, and the resulting NH4⁺ was determined by the novel gas-phase molecular absorption spectrometric technique. An atomic absorption spectrophotometer, with a flow-through absorption cell replacing the flame, was used in the analysis. Recovery of amygdalin was 98.4 ± 1.2% complete. Cyanogenic glycoside contents determined in seeds (0.93% for apple, 2.05% for cherry, 2.43% for peach, and 0.00% for almond, reported in terms of amygdalin), were confirmed by a standard titration method. The lowest detectable concentration was 0.2 μg NH4⁺/mL, which corresponds to a detection limit of 0.5 mg amygdalin in the seed sample.
Cyanogenic glycosides are secondary metabolites that are found in various plant tissues and produce HCN upon hydrolysis. They are widely distributed in the plant kingdom and are synthesized during metabolism of aromatic amino acids such as phenylalanine and tyrosine and branched amino acids such as leucine, isoleucine and valine. Flaxseed contains linamarin, linustatin and neolinustatin. Cyanogenic glycosides can be quantified in the intact form by chromatographic methods or indirectly by determining the content of HCN released due to their decomposition. The ability of cyanogenic glycosides to release HCN is due to their enzymic hydrolysis which may cause cyanide poisoning. Therefore, removal of cyanogenic glycosides is necessary to improve the nutritional value and safety of cyanogen containing foods including flaxseeds.
The levels of antinutritional and toxic factors were determined in several Philippine indigenous legumes, namely, hyacinth bean (Dolichos lablab L.) lima bean (Phaseolus lunatus L.), sabawel or velvet bean (Mucuna curanii), sam-samping (Clitoria ternatea), rice bean (Vigna umbellata), jackbean (Canavalia ensiformis), and swordbean (Canavalia gladiata). Low levels of condensed tannins (0–2.48 mg catechin /g) and protein-precipitable polyphenols (0.16–0.77 mg tannic acid/gram) were observed in raw mature seeds of the six legumes analyzed in this preliminary study. Seeds of hyacinth bean, jackbean, and lima bean had relatively high levels of phytate phosphorus ranging from 6.6 to 11.6 mg of phytate P/g of sample. Lower values ( <5) were obtained for sabawel and swordbean as well as some varieties of mungbean used as controls. The indigenous legumes analyzed had low levels of less than 50 μg/g of cyanide in the seeds, immature and mature leaves, and immature pods using two methods of analysis. Among the legumes investigated, hyacinth bean had the highest trypsin inhibitor activity ranging from 14 to 27 units/mg sample for four accessions. Accession 6-1 of sabawel had 20 units/mg. Sword bean and jack bean had low levels of 1 to 5 units/mg except for one jack bean accession (A-1) which had 9 units/mg. Rice bean also had low levels of trypsin inhibitor activity, 5–7 units/mg.
Eighteen varieties of limabean (Phaseolus lunatus), were subjected to the processes of cooking, autoclaving, soaking in water and germination for 6 days. The effects of these processes on the free and bound HCN contents of the raw limabean varieties were investigated. Total HCN in the raw varieties ranged from 265 mg kg−1 in TPL 071-33 and 553 mg kg−1 in TPL 13. Considerable variability was encountered in the different varieties and processing effects tended to make these varietal differences even more pronounced. Autoclaving gave a mean total loss of 53·9% in total HCN content while cooking effected a 64·8%–81·9% loss in total HCN content. Drastic reductions in both free and bound HCN contents were obtained in all cooked varieties. Soaking for 2 days effected the highest HCN loss in TPL 2 (40·1%), closely followed by TPL 13 (39·7%) and then TPL 3 (35·4%). All varieties, by the sixth day of soaking, lost between 61·3 and 86·4% of their total HCN contents. The effect of germination on HCN contents increased progressively from a mean total loss of 24·5% in day 2 to 55·6% in day 4 and 76·1% in day 6. Cooking and germination for 6 days appeared to be equally effective in reducing free and bound contents. Autoclaving was the least effective of all the processes studied.
The sensitivity of the normal picrate method for determination of total cyanide in cassava was increased tenfold using a small 1cm2 picrate paper, eluted using 0.5mL instead of 5mL of water as in the normal method. The absorbance was measured in a 2mm cuvette in the spectrophotometer. The sensitive method was calibrated against the normal picrate method. The total cyanide content in mg HCN equivalents/kg sample = ppm, is calculated from the absorbance (A) by the equation ppm = A×45.7 which is applicable from 0.1 to 50ppm. A new method to determine acetone cyanohydrin was developed based on irreversible denaturation of linamarase in 0.1M HCl at 30°C for 1h. Five gari samples from Mozambique gave a mean total cyanide content of 12ppm (range 6–15ppm) and mean acetone cyanohydrin content of 11ppm (range 5–14ppm). Acetone cyanohydrin liberates cyanide quantitatively in the human intestine.
The changes in the nitrogenous compounds of flaxseed during an 8-day germination period were studied. The dry matter content of the seeds was reduced by 35% at the end of the germination. During the germination period, a relatively small decrease was observed in total nitrogen content, but there was an increase in the content of non-protein nitrogen from 9 to 33.5% of the total amount. An increase in the total content of free amino acids was also observed. Among individual amino acids, glutamine showed a marked change during the germination period indicating that it is the favoured amide donor in the developing flax seedlings. An increase in the water-soluble protein and a decrease in the salt-soluble protein fractions was also observed. The content of polyamines, namely agmatine, spermidine and putrescine, which are important in controlling cellular metabolism and growth, was also increased during the germination period. After day 8 of germination, the contents of cyanogenic glycosides, linustatin and neolinustatin in the seeds were reduced by 40 and 70%, respectively. Trypsin inhibitor content was very low in flaxseed and only trace amounts were present after 8 days of germination.
Cyanogenic glucosides were quantified in different organs of oil flax (Linum usitatissimum cv LCSD 200) plants at different stages of development. Monoglucosides (linamarin and lotaustralin) and diglucosides (linustatin and neolinustatin) appeared in developing embryos soon after anthesis, but mature seeds accumulated only diglucosides. Monoglucosides appeared again in germinating seeds and, in young seedlings, they were the only class of cyanogens. High levels of linamarin and lotaustralin were found in leaves throughout the vegetation period, but the highest amounts were in flowers. In contrast, these glucosides occurred in relatively small amounts in roots and in stems. The possible physiological roles of the changes are discussed.
The simple semiquantitative picrate method for the determination of total cyanogens in cassava flour has been modified by increasing the concentration of the picrate solution used to make up the picrate papers, such that a linear Beer's Law relation between absorbance and cyanogen content is obtained over the range 0–800 mg HCN equivalents kg−1 cassava. The method has been adapted to determine the total cyanogen content of cassava roots and the results compared using the picrate method and the acid hydrolysis method for six different roots from five cultivars. The agreement between the results is satisfactory. The simple method for determination of total cyanogens in cassava roots in the field is available in kit form. The methodology has been modified to allow determination of the three different forms of cyanogens present in cassava flour, viz HCN/CN−, acetone cyanohydrin and linamarin. HCN/CN− is determined by the picrate method in which cassava flour is reacted with 0.1 M sulphuric acid for 3 h at room temperature. HCN/CN− plus acetone cyanohydrin is also determined by the picrate method after treating cassava flour with 4.2 M guanidine hydrochloride at pH 8 for 3 h at room temperature. A comparison has been made of the amounts of the three cyanogens present in six cassava flour samples using the semiquantitative picrate and the acid hydrolysis methods. The agreement between the two methods is satisfactory, which shows that the new methodology works well. The picrate method for determination of the three cyanogens in cassava flour is also available as a kit.© 1999 Society of Chemical Industry
Five mandelonitrile glycosides have been detected in the glycosidic fraction isolated from several Passiflora fruits using GC/EI-MS or GC/NCI-MS of trifluoroacetylated derivatives. Reasons for the possible co-occurence of prunasin and sambunigrin in passion fruit juice and peel are given, and amygdalin is reported for the first time as a passion fruit component. Two mandelonitrile rhamnopyranosyl β-d-glucopyranosides have been tentatively identified by MS. The extraction of cyanoglycosides using Amberlite XAD-2 followed by GC analysis of TFA derivatives was found to be an efficient method for their rapid determination. Prunasin was found to be the most important cyanogenic glycoside in peel (285 mg/kg for P. edulis f. flavicarpa), whereas amygdalin (31 mg/kg for P. edulis) and the two compounds tentatively identified as mandelonitrile rhamnopyranosyl β-d-glucopyranosides were mostly found in the juice (99 mg/kg for P. edulis f. flavicarpa). Different amounts of sambunigrin were found in the juice and the peel (from 0.4 mg/kg in P. edulis juice to 15.5 mg/kg in P. edulis f. flavicarpa peel). Keywords: Passion fruit; cyanogenic glycosides; gas chromatography; mass spectrometry
A crude enzyme extracted from flaxseed by acetone precipitation was used for the hydrolysis of cyanogenic glycosides to determine total cyanide in flaxseed and flaxseed-derived products. The hydrolysis of cyanogenic glycosides (linamarin, linustatin, and neolinustatin) as well as the endogenous substrate was dependent on the crude enzyme concentration and followed a first-order relationship. Two colorimetric methods using the crude enzyme extract and an established high-performance liquid chromatographic (HPLC) method were compared using 28 flaxseed samples. Total HCN values obtained by all three methods were not statistically different, although those obtained by the HPLC method were higher than those from the colorimetric methods. Keywords: Flaxseed; cyanogenic glycosides; method comparison; crude enzyme extract; Linum usitatissimum; barbituric acid−pyridine; HPLC
The seeds of 10 flax cultivars (Andro, Flanders, AC Linora, Linott, McGregor, Noralta, NorLin, NorMan, Somme, and Vimy) grown at Portage la Prairie, MB, in 1987, 1988, and 1989 and at Beaverlodge, AB, and Indian Head, SK, in 1989 were analyzed for content of cyanogenic glucosides by HPLC. The main cyanogenic compound was the diglucoside linustatin at 213-352 mg/100 g of seed, accounting for 54-76% of the total content of cyanogenic glucosides. The content of neolinustatin ranged from 91 to 203 mg/100 g of seed. Linamarin was present at low levels (<32 mg/100 g) in 8 of the 10 cultivars analyzed. The content of all three cyanogenic glucosides was dependent on cultivar, location, and year of production, with cultivar being the most important factor.
Guided by the results of NMR experiments on the reactivity of linamarin in alkali and acid, an acid hydrolysis method was developed for cyanide analysis in cassava. Hydrolysis in 2·0 M H2SO4 at 100°C for 50 min of a cassava extract produced cyanohydrins which rapidly decomposed to cyanide ion in alkali. Excess pH 6 buffer was added, followed by chloramine-T and pyridine/barbituric acid (König reaction) to produce a purple solution which was measured spectrophotometrically at 583 nm. The colour intensity depended on pH and phosphate concentration, hence accurate results required similar solution conditions for KCN standards. The method gave reasonable agreement with results obtained by the use of linamarase, and adequate recoveries of added linamarin (70–95% dependent on conditions). Acid hydrolysis is cheaper than the enzymic method using linamarase, which is expensive. Also the pyridine/barbituric acid reagent used in the acid hydrolysis method is cheaper and more stable than the pyridine/pyrazolone normally used in the enzymic method. Six locally grown cultivars gave <30 mg HCN kg−1 fresh tuber, and one cultivar (SM 1–150) contained only 4 mg HCN kg−1 fresh weight. Analyses of the same cultivar grown more recently gave values of 13–27 mg HCN kg−1, showing the need for a study of the environmental factors influencing the cyanide content of cassava tubers.
A survey has been made of the total cyanogen content of cassava roots and products from the cassava growing provinces of Lampung and East, Central and West Java, in Indonesia. Twenty five samples of cassava products were analysed for cyanogens by the acid hydrolysis method and also by the simple picrate kit method. The mean percentage difference between the results was 17%. Thirty samples of cassava starch and other specialised products had a mean cyanogen content of only 5 ppm, whereas 29 samples of cassava flour, chip and gaplek gave a much higher mean cyanogen content of 54 ppm (SD 51). The WHO safe value for cassava flour is 10 ppm and the Indonesian level is 40 ppm. There are four outliers of cyanogen content 140–200 ppm, which would be dangerous to human health. The cyanogen content of starch/chips/gaplek needs to be reduced by using cultivars of lower cyanogen content and by using improved processing methods. Twenty seven samples of cassava roots gave a mean cyanogen content of 19 ppm (SD 14). ©
A general method has been developed for determination of the total cyanide content of all cyanogenic plants and foods. Ten cyanogenic substrates (cassava, flax seed, sorghum and giant taro leaves, stones of peach, plum, nectarine and apricot, apple seeds and bamboo shoot) were chosen, as well as various model compounds, and the total cyanide contents determined by the acid hydrolysis and picrate kit methods. The hydrolysis of cyanoglucosides in 2 M sulfuric acid at 100oC in a glass stoppered test tube causes some loss of HCN which is corrected for by extrapolation to zero time. However, using model compounds including replicate analyses on amygdalin, the picrate method is found to be more accurate and reproducible than the acid hydrolysis method. The picrate kit method is available free of charge to workers in developing countries for determination of cyanide in cassava roots and cassava products, flax seed, bamboo shoots and cyanide containing leaves. For eleven different samples of flax seed and flax seed meal the total cyanide content was 140–370 ppm. Bamboo shoots contained up to 1600 ppm total cyanide in the tip reducing to 110 ppm in the base. The total cyanide content of sorghum leaves was 740 ppm 1 week after germination but reduced to 60 ppm 3 weeks later. The acid hydrolysis method is generally applicable to all plants, but is much more difficult to use and is less accurate and reproducible than the picrate method, which is the method of choice for plants of importance for human food.
This study investigated the effects of cassava processing techniques in reducing cyanogen levels to low levels during the production of some Cameroonian foods (bâton de manioc, fufu and gari). The processing techniques used for each of the foods did not vary in details from one processor to the other, and no considerable differences were found in neighbouring villages. They were highly effective in substantially reducing mean total cyanogen contents (197.3–951.5 mg HCN equivalent/kg) to low levels (1.1–27.5 mg HCN equivalent/kg). In spite of the different cassava varieties used for processing, similar mean reduction levels (97.1–99.8%) in total cyanogens were obtained by the processors: 98.8%, 97.1% and 99.7% for bâton de manioc, fufu and gari, respectively. With regard to the greatest changes in total cyanogens, the most important techniques were those that maximise root tissue disintegration causing marked decreases in both linamarin and pH levels, which coincided with significant increases in cyanohydrin. The residual cyanogens were in the form of cyanohydrin, which were partially removed during post-fermentation processes.
The total cyanogenic potential of various substrates (flax seed, stones of peach, plum, nectarine and apricot as well as apple seeds, and various model compounds) was investigated by using the acid hydrolysis method, picrate method, and a novel method based on the reaction of cyanide liberated from plants with resorcinol and picrate. The hydrocyanic acid liberated from cyanogens was trapped by using a 1% sodium bicarbonate. Then, 1 ml of extract was mixed with 1 ml of working reagent containing 160 microg of resorcinol, 320 microg of picric acid, and 30 mg of sodium carbonate, and heated on a boiling water bath for 10 min. The absorbance was measured at 488 nm in 1cm glass cuvettes at room temperature. The color system obeys Beer's law in the range of 0-5 microg ml(-1) total HCN. Using model compounds and real samples including replicate analyses on prunasin, the resorcinol method proved to be more accurate, reproducible, and especially more sensitive than the known spectrophotometric methods such as the acid hydrolysis method and the picrate method.
Grated cassava to which tap water was added at levels of 25%, 50% and 75% (v/w) was held at 30 degrees C, 40 degrees C or 50 degrees C and examined over a 6 h period for cyanide content, pH and titratable acidity (TTA). During the come-up time, i.e. the time between addition of water and attainment of desired holding temperature (between 14 and 47 min), reductions in bound cyanide of ca 54-85% occurred, depending on the level of added water and holding temperature. The corresponding losses for the control samples, to which no water was added, were ca 25-33%. The biggest reduction in the bound cyanide of > 99% (from 89.0 to 0.6 ppm) occurred in grated cassava with 75% added water held at 50 degrees C. There was little or no change in pH during the period of study. The reduction of processing time for certain cassava products based on separation into detoxication and flavour development/fermentation stages is discussed.
A comprehensive review on the presence of certain important anti-nutritional and toxic factors in food legumes has been conducted. These substances include proteolytic inhibitors, phytohemagglutinins, lathyrogens, cyanogenetic compounds, compounds causing favism, factors affecting digestibility and saponins. These factors are shown to be widely present in leguminous foods which are important constituents of the diet of a large section of the world's population, and particularly, of people in the developing countries.
Laetrile preparations obtained from a cyanide intoxicated patient were analyzed for their cyanide content by a microdiffusion colorimetric procedure. Cyanide was also determined in apricot, peach and apple seeds. The results were compared to those reported in the literature for cyanogenic glycoside containing seeds.
The cyanogen of Passiflora edulis Sims is identified as prunasin [2(R)-(β-D-glucopyranosyloxy)-2-phenylacetonitrile] by 1H NMR. Quantitative assay of hydrogen cyanide in leaves and fruit at different stages of development shows potentially toxic levels to be present. Passion fruits contain the greatest amount of cyanide when immature, losing most of their cyanogenic capacity as they ripen. No significant difference was detected between edible and nonedible portions of fruit.
Flaxseed is increasingly being used in some food products because of its high content of alpha-linolenic acid and dietary fibre. However, flaxseed contains cyanogenic glycosides which release toxic hydrogen cyanide in the presence of water (autohydrolysis). A method for estimation of cyanide in flaxseed under these conditions is described. The determination is carried out by homogenizing the sample with water, letting it stand, filtering it through a membrane and then injecting the filtrate into an HPLC system consisting of an anion exchange column and an electrochemical (amperometric, oxidation) detector. The homogenate is analysed at various intervals until a maximum value of cyanide is observed. The cyanide content of ten cultivars of flaxseed, when analysed by this method, was found to range from 124 to 196 micrograms/g. The release of cyanide showed a maximum at about 3 h of hydrolysis. Virtually no cyanide was detected on boiling the homogenate or the flaxseed before determination.
The cyanide levels were followed during protein enrichment of cassava by the fungus Aspergilus oryzae. The total cyanogen level decreased by 158 mg/kg dry weight to 54.2 mg/kg dry weight as a result of the whole process including fermentation. The cyanogenic glucoside level decreased by 88% during the fermentation process while acetone cyanohydrin was retained in the cassava. The prefermentation processing which involved crushing, sundrying and milling the cassava into flour, reduced the total cyanogen levels by 40%. The process resulted in considerable reduction in the cyanogenic content of the product.
The population and composition of the lactic acid bacteria microbiota as well as the content of cyanogenic glucosides occurring at various stages of fermentation and subsequent processing of cassava roots into akyeke, a steamed sour cassava meal, were investigated. The number of lactic acid bacteria and percentage titratable acidity increased during 5 days of fermentation, but decreases were observed in the subsequent operations of 'washing' the dough with water followed by partial drying and steaming. In field and laboratory samples, Lactobacillus plantarum accounted for 59.3% and 52.3%, Lactobacillus brevis 23.3% and 22.8% and Leuconostoc mesenteroides subsp. cremoris 14.5% and 15.8%, respectively, of all lactic acid bacteria isolated at various stages of fermentation and processing. A reduction of about 98% occurred in the total cyanogens (CN) content of cassava roots during processing, from 69.3 to 1.4 and 110.3 to 2.8 mg CN equivalent/kg dry weight for laboratory and field samples of akyeke, respectively.
Young shoots or sprouts of common bamboos are used as food in third world countries. Evidences suggest the presence of cyanogenic glucoside like anti-thyroidal substance in bamboo shoots (BS) but effect of prolonged BS consumption on thyroid status under conditions of varying iodine nutriture remains unexplored. The study was undertaken to evaluate goitrogenic content, in vitro anti thyroid peroxidase (TPO) activity and in vivo anti thyroid potential of BS with and without extra iodide. Fresh BS contains high cyanogenic glucoside (551 mg/kg), followed by thiocyanate (24mg/kg) and glucosinolate (9.57mg/kg). In vitro inhibition in TPO activity was found with raw, raw boiled and cooked extracts. Inhibition constant (IC50) and PTU equivalence of fresh BS were 27.5+/-0.77 microg and 3.27 respectively. Extra iodide in the incubation media reduced TPO inhibition induced by BS but could not cancel it. Thyroid weight, TPO activity and total serum thyroid hormone levels of BS fed animals for 45 and 90 days respectively were determined and compared with controls. Significant increase in thyroid weight as well as higher excretion of thiocyanate and iodine along with marked decrease in thyroid peroxidase activity, T4 and T3 levels were observed in BS fed group. Chronic BS consumption gradually developed a state of hypothyroidism. Extra iodide had reduced the anti-thyroidal effect of BS to an extent but could not cancel it because of excessive cyanogenic glucoside, glucosinolate and thiocyanate present in it.
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