A STUDY ON THE DETERMINATION OF HYDROGEN CYANIDE IN CASSAVA

ABSTRACT

The research was conducted in order to determine the concentration of cyanide in cassava turbers and apple seeds consumed in Zaria and to compare the level of cyanide in cassava tubers using different drying methods. This was determined using alkaline titration method as described by Kamalu and Oghoma. The results obtained shows that oven dried cassava has the highest concentration (2.61±0.31ppm) followed by air dried cassava (2.54±0.05ppm), fresh apple seed (1.94±0.09pmm) and undried Cassava (1.53±0.16ppm). When wet apple seeds are compared with wet cassava, the apple seeds have higher concentration (1.94±0.09ppm and 1.53±0.16ppm respectively. According to Food Safety Focus (2008), the acute lethal dose of hydrogen cyanide for humans is reported to be 0.5 to 3.5 mg per kilogram of body weight. Children are particularly at risk because of their smaller body size. These results indicate that consumption of 6 – 7 apple seeds (0.7g) is enough to poison a child of 7 -10 kg weight. We recommend that all products obtained from cassava should be analyse for cyanide concentration to ensure safety of the masses.

CHAPTER ONE INTRODUCTION

1.1 BACKGROUND OF THE STUDY

 Cassava is the third largest source of carbohydrates food in the tropics, after rice and maize. Cassava is the staple food of more than 500 million people in the tropics, many of whom are very poor (Katz and Weaver,2003). According to New World Encyclopedia (2008), it is one of the world’s most perishable tuber crops with a high post-harvest loss. Anomically cassava root is not a tuberous root but a true root which cannot be used for vegetative propagation. The three distinct tissues of the mature cassava tuber include; the periderm,cortex and pulp which is the edible portion of the fresh root. Apple(Malus) is a genus of about 30–55 species of small deciduous trees or shrubs in the family Rosaceae, including the domesticated orchard apple – also known as the eating apple, cooking apple, or culinary apple. It is dealt with under Apple. The other species are generally known as crabapples, crab apples, or wild apples According to Wheatley and Chuzel (1993), the cyanide concentration in cassava varies in different part of the plant. Cassava is of a lower nutritional value than cereals, legumes, and even some other root and tuber crops such as yam (Charles et al., 2005). Cassava roots contain significant amount of iron, phosphorus, calcium and vitamin C, but is a poor source of protein. The root contains carbohydrate 64- 72% of which is made up of starch, mainly in the form of Amylose and Amyl pectin. About 17% sucrose is found in sweet varieties and small amounts of fructose DOI: http://dx.doi.org/10.22192/ijcrcps.2019.06.02.003 Int. J. Curr. Res. Chem. Pharm. Sci. (2019). 6(2): 14-20 © 2019, IJCRCPS. All Rights Reserved 15 and dextrose have been reported (Hendershort, 1972), the lipid content of cassava is 0.5%, protein content is about 1-2% and the amino profile of the cassava root is very low,cassava is reasonably rich in calcium and vitamin C, but the thiamine and riboflavin and niacin contents are not high (Hair, 1998; RMKDC, 2004; New World Encyclopedia, 2008). So therefore, the two distinct types of cassava are the sweet cassava (Manihot dulcis) and the bitter cassava (Manihot esculenta). The bitter cassava is associated with high level of cyanogenic glucoside. Cyanide Cyanide is a chemical compound that contains the group C≡N. this group known as the cyano group consist of a carbon atom triple bonded to a nitrogen atom. According to Gosselin et al, (1984), cyanide can be produced by certain organisms (e.g bacteria, fungi, and algae), and equally in plant. According to Greenwood and Eamlaw (1992) free cyanide is defined as the sum of the cyanide present as CN- . As a result, low level of cyanide can appear in naturally occurring surfaces or ground water, which normally would not be expected to contain it (US fish and wildlife service, 1991). According to Duffey (1981), anthropogenic sources of cyanide include synthetic catalytic process involving reaction of ammonia and natural gas with or without air. Hydrogen cyanide may be obtained as a by- product in the production of acrylnitrite. Other cyanide like sodium and potassium are principally prepared by direct reaction of hydrogen cyanide released to air as a result of chemical manufacturing and processing industries, volatilization of cyanide waste deposit in landfill and waste pond. Some sources of cyanide arise from cigarette smoke, are generated when some certain synthetic material such as plastics are burned. Much of the cyanide in soil, water and air comes from industrial processing, gold mining, and waste waters from starch industries. The major sources of cyanide in water are discharged from metal mining processes. Other sources include exhaust released from certain chemical industries, municipal waste burning and use of pesticides containing cyanide. Underground water can be contaminated by cyanide present in landfills. In other body, cyanide can be combined with plant foods including almonds, millet sprouts, lima beans, soy spinach, bamboo shoot and cassava root. Cyanide occurs as part of naturally occurring sugars or other complex organic compound. In humans, cyanide is a well known poison with potential acute and chronic metabolic effect (Kakes, 1990). Cyanide exacts its toxic effect by binding ferric ion with cytochrome, an enzyme that account for about 90% of total oxygen uptake in most cells through electronic transport chain. Human get exposed to cyanide mainly by breathing, drinking water, eating foods and touching soils. Some symptoms of acute poisoning include, mental confusion, muscular paralysis and respiratory distress (Kakes, 1990). Large amount of cyanide may be responsible for visible manifestations as goiter and cretinism (Bradbury, 2004).

1.2 STATEMENT OF THE PROBLEM

Cassava is grown in Zaria as a subsistence crop, its utilization as food varies from region to region, it is a source of food, serenity not only because it can be grown on less productive land, but because it is a source of income for the urban and rural population. People in many parts of Nigeria rely largely on starchy foods for their carbohydrate intake, cassava being a major source of carbohydrate is becoming a major source of food. The crop’s agronomical advantages such as high productivity ease and flexibility of cultivation, tolerance to drought and its ability to grow well on relatively poor soil has made it rapidly and extensively adaptable. The status of cassava as a food security crop to most subsistence farmers is however threatened by pest, diseases and weed, and potential toxicity in cassava is due to the presence of cyanogenic glycoside potential for production of poisonous hydrogen cyanide. Apple is widely consumed for its attractive look, taste and other medicinal purposes. The seeds are usually not consumed but often consumed accidentally or ignorantly and its contains (cyanide) are harmful. Apple seeds contain amygdalin, which is converted into cyanide when the seeds are chewed or crushed. Cyanide is highly poisonous and can be deadly in high doses. The research seeks to determine the concentration of cyanide in cassava and apple seed consumed in zaria and its environs and to compare the concentration of cyanide in cassava under different drying processes (moist, sun-dry, air-dry and oven dry cassava).

1.3 SIGNIFICANCE OF THE STUDY

 Information obtained in this study on the determination of cyanide content in cassava and apple seeds will be crucial for awareness campaign to its users. Such information will be very important for Int. J. Curr. Res. Chem. Pharm. Sci. (2019). 6(2): 14-20 © 2019, IJCRCPS. All Rights Reserved 16 extensive services towards training of farmers and consumers by agricultural officers and other regulatory body on effective method of processing cassava. Cyanide Toxicity Cyanide toxicity is generally considered to be a rare form of poisoning. However, cyanide exposure occurs relatively frequently in patients with smoke inhalation from residential or industrial fires (Holstege and Kirk, 2015). In addition, intensive treatment with sodium nitroprusside or long term consumption of foods containing cyanide is a possible source of cyanide poisoning (Abraham, Buhrke and Lampen, 2016; Akyildiz, Kurtoglu, Kondolot and Tunc, 2010). Historically, cyanide has been used as a chemical warfare agent, and it could potentially be an agent for a terrorist attack (Armstrong 2002). Depending on its form, cyanide may cause toxicity through inhalation, ingestion, dermal absorption or parental administration. Clinical administration may vary widely, depending on the dose and route of exposure, and may range from minor upper airway irritation to cardiovascular collapse and death within minutes. In severe cases, aggressive therapy consisting of supportive care and antidote administration can be lifesaving.

REFERENCES

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