Proximate Analysis of Celery

CHAPTER ONE

1.0 INTRODUCTION

From ancient times, plants have been used for treatment of human diseases. Since the time of early Neanderthal man, medicinal plants are the source of health care management (Farnsworth et al., 1985). The exploration of the chemical constituency from plants and pharmacological screening will provide the basis for developing new molecules in strategic favour of natural product of drug discovery.

Vegetables are important in rational nutrition, thanks to a rich content of nutrients and energy, especially as a favourable influence on the functions of the physiologic human organism. Most vegetables taste like, with different shades of one variety to another, some of which are rich in essential oils, glycosides, pigments etc. which stimulates appetite. The large number of species, varieties and varieties of vegetables are raw material for preparing a variety of foods, thus improving range enriching food. The chemical composition of vegetables shows high water content, sugars, protein, starch, fat, energy value (in calories), etc.

Comparing vegetables and other foods of animal origin can say that vegetable products have a lower food value and a lower heat, but have special importance in human nutrition, the high content of vitamins, minerals etc. Many species of vegetables containing high amounts of digestible carbohydrates (starch, sucrose, glucose, fructose), non-digestible carbohydrates (cellulose, hemicellulose, pectin, protides).

Apium graveolens L. (Apiaceae), celery, is a native of Eurasia and is grown mainly in coastal regions. Celery is widely cultivated in the temperate zones as an important garden crop and the bleached leaf stalks are relished as a popular vegetable (Jung et al, 2011). Apium graveolens is one of the ingredients in 8 of the 33 Indian polyherbal formulations with reputed life protecting activity (Handa et al, 1986). The characteristic door of celery essential oil is due to a series of phthalide derivatives.

Celery (Apium graveolens L.) is a plant, belonging to the parsley descent (Umblliferace), an herbaceous, biennial, and branched stem plant, with a height of 20 to 60 cm (Nasri et al., 2009). Celery leaves contain different compounds such as valerophenone (19.90%), 1-dodecanol (16.55%), 9-octadecanoic acid, and methyl ester (4.93%) (Nagella et al., 2012). The juice of celery leaves and roots possesses effective biochemical parameters, such as reduced glutathione content, catalase, xanthine oxidase, glutathione peroxidase, and peroxidase activities which affect the intensity of lipid peroxidation in homogenized liver and blood. When this extract is used in combination with doxorubicin, a protective effect is induced against it. (Kolarovic et al., 2009).

Celery seeds are known to have carminative, stimulant, stomachic, emmenagogue, diuretic, antirheumatic, anti-inflammatory, and laxative properties, it is prescribed for epilepsy or psychiatric problems due to its tranquilizing effect. The oil is used to treat asthma, flatulence, and bronchitis. Leaves and petioles are used for skin problems in addition to the above-mentioned uses (Khare, 2007).

The content and chemical composition of the essential oil of celery and other aromatic plant species are dependent on a number of factors: genetic, ontogenetic and environmental as well as agronomic factors i.e. fertilization, irrigation, cultivation method, and harvesting method (Benbelaid et al., 2013, Nurzyńska-Wierdak et al., 2014, Aćimović et al., 2015).

However, the consumption of vegetables has been on the decline with each passing decade. The neglect of vegetables in our diets prompted this study. The study is aimed at evaluating the levels of various macronutrients in Apium graveolens. It is hoped that this study will increase interest in it and other beneficial vegetables.

CHAPTER TWO

2.0 LITERATURE REVIEW

2.1 HISTORY

Celery (Apium graveolens) has been used in decoration from ancient times. It was part of the garlands found in the tomb of the Pharaoh Tutankhamen (died 1323 BC), and celery mericarps dated to the seventh century BC were recovered in the Heraion of Samos (Zohary and Hopf, 2000). But celery grew wild in these areas, so it was hard to ascertain whether these remains were the wild or cultivated forms. In the classical times, it was finally found out that celery could be cultivated.

There are archaeological finds of celery dating as far back as the 9th century BC, at Kastanas; however, the literary evidence for ancient Greece is far more abundant. In Homer's Iliad, the horses of the Myrmidons graze on wild celery that grows in the marshes of Troy, and in Odyssey, there is mention of the meadows of violet and wild celery surrounding the cave of Calypso (Fragiska, 2005).

Celery’s late arrival in the English kitchen is an end-product of the long tradition of seed selection needed to reduce the sap’s bitterness and increase its sugars. It makes an appearance in colonial American gardens where it was just seen as one of the species of parsley; but by the mid-19th century, the need for refined crisp texture and taste brought celery to American tables, where it was served in celery vases to be salted and eaten raw.

2.2 DESCRIPTION AND VARIETIES

Celery leaves are pinnate to bipinnate with rhombic leaflets 3–6 cm (1.2-2.4 in) long and 2–4 cm (0.79–1.57 in) broad and the flowers are creamy-white, 2–3 mm (0.079–0.118 in) in diameter, and are produced in dense compound umbels; the seeds are broad ovoid to globose, 1.5–2 mm (0.059–0.079 in) long and wide (https://en.m.wikipedia.org/wiki/Celery).

Modern cultivars have been selected for solid petioles, leaf stalks (de Vilmorin, 1950). A celery stalk readily separates into "strings" which are bundles of angular collenchyma cells exterior to the vascular bundles (Peterson et al., 2008).

North America: In North America, commercial production of celery is dominated by the cultivar called 'Pascal' celery (de Vilmorin, 1950). Gardeners can grow a range of cultivars, many of which differ from the wild species, mainly in having stouter leaf stems. They are ranged under two classes, white and red. The stalk grow in tight, straight, parallel bunches, and are typically marketed fresh that way, without roots and just a little green leaf remaining. The stalks are eaten raw, or as an ingredient in salads, or as a flavouring in soups, stews, and pot roasts.

Europe: In Europe, another popular variety is celeriac (also known as celery root), Apium graveolens var. rapaceum, grown because its hypocotyl forms a large bulb, white on the inside. The bulb could be kept for months in winter and mostly serves as a main ingredient in soup. It can also be ground up and used in salads. The leaves are used as seasoning; the small, fibrous stalks find only marginal use.

Asia: Leaf celery (Chinese celery, Apium graveolens var. secalinum) is a cultivar from East Asia that grows in marshlands. Leaf celery is most likely the oldest cultivated form of celery. Leaf celery has characteristically thin skin stalks and a stronger taste and smell compared to other cultivars. It is used as flavouring in soups and sometimes pickled as a side dish (Newman, 2006).

Wild: The wild form of celery is known as "smallage". It has a furrowed stalk with wedge-shaped leaves, the whole plant having a coarse, earthy taste, and a distinctive smell. The stalks are not usually eaten (except in soups or stews in French cuisine), but the leaves may be used in salads, and its seeds are those sold as a spice. With cultivation and blanching, the stalks lose their acidic qualities and assume the mild, sweetish, aromatic taste particular to celery as a salad plant. Because wild celery is rarely eaten, yet susceptible to the same diseases as more well-used cultivars, it is often removed from fields to help prevent transmission of viruses like celery mosaic virus (Wellman, 1937).

2.3 SCIENTIFIC CLASSIFICATION

Kingdom: Plantae

Clade: Angiosperms

Clade: Eudicots

Clade: Asterids

Order: Apiales

Family: Apiaceae

Genus: Apium

Species: Apium graveolens

2.4 NUTRITIONAL CONTENT

Celery leaf is a good source of vitamins K, B9 and B6. It has about 1.34% of sugars and 95% water by weight, and provides many nutritional benefits in the form of vitamins and minerals —sodium, potassium, magnesium, calcium and copper. The composition of celery per 100g edible portion includes:

Water — 95.43%

Energy — 16kcal

Protein — 0.69g

Fat — 0.17g

Carbohydrate — 2.97g

Calcium — 40 mg, copper — 0.035 mg, iron — 0.20 mg, magnesium — 11 mg, phosphorus — 24 mg, potassium — 260 mg, sodium — 80 mg and zinc — 0.13 mg. Celery also contains antioxidants. (Source: USDA Nutrient Database, 2002).

Celery leaf is used in weight-loss diets, where it provides low-calorie dietary fibre bulk. Celery is often incorrectly thought to be a “negative-calorie food", the digestion of which burns more calories than the body can obtain. In fact, eating celery provides positive net calories, with digestion consuming only a small proportion of the calories taken in (Nestle and Neshiem, 2012).

2.5 HERBALISM

Celery seeds have been used widely in Eastern herbal traditions such as Ayurveda (University of Maryland Medical Centre, 2015). As at A. D. 30, celery seeds have been used in the relief of pains. Though scientific evidence is lacking, it is still used as in ancient times for water retention, arthritis, and inflammation, and has seen more recent uses for reducing blood pressure and muscular spasms and as a mosquito repellent (University of Maryland Medical Centre, 2015).

2.6 CHEMISTRY

Polynesia can be found in Apiaceae vegetables like celery, and their extracts show cytotoxic activities (Zadora et al, 2005; Minto and Blacklock, 2008). Celery contains phenolic acid, which is an antioxidant (Yang, 2010).

Apiin and apigenin can be extracted from celery and parsley. Lunularin is a dihydrostilbenoid found in common celery. The main chemicals responsible for the aroma and taste of celery are butylphthalide and sedanolide (Wilson, 1970).

2.7 PROXIMATE ANALYSIS

Proximate analysis is the partitioning of compounds in a substance into categories based on the chemical properties of the compounds. The different classes include: ash, moisture, crude protein, crude fat, nitrogen free extract and crude fibre.

2.8 ASH

Ashing is the process of mineralization for pre-concentration of trace substances prior to chemical analysis (IUPAC, Compendium of Chemical Technology, 2016). Ash is the name given to all non-aqueous residues that remain after a sample is burned, which consists mostly of metal oxides. Ash is one of the components of proximate analysis of biological materials, consisting mainly of salty, inorganic constituents. It includes metal salts which are important for processes requiring ions such as Na+, K+, and Ca2+. It also includes trace minerals which are required for unique molecules such as chlorophyll and haemoglobin.

2.9 MOISTURE

Moisture refers to liquids especially water often in trace amounts. Small amounts of water may be found, for example, in the air (humidity), in foods, and in various commercial products.

Moisture control in products can be a vital part of the processing of the product. There is a substantial amount of water (moisture) in what seems to be dry matter. There are two main aspects of concern in moisture control in products; allowing too much moisture or too little of it. Example, adding some water to cornflake cereal, which is sold by weight, reduces cost, and prevents it from tasting too dry, but too much water can affect the crunchiness of the cereal and the freshness because water content contributes to bacteria growth; moisture has different effects on different products.

2.10 PROTEINS

Proteins are one of the major structural components of cells in the body. It functions as enzymes and hormones needed for the production of neurotransmitters, vitamins, antibodies, and other important molecules. They are made up of chains of nitrogen-containing amino acids.

Proteins are the most abundant biomolecules other than water. The interior a cell is an extraordinary complex environment in which proteins and other macromolecules are present. Different proteins are distinguished by a different order of amino acid in the polymeric sequence of such typically 300 building blocks. Following synthesis, the majority of the proteins must be converted into tightly folded compact structures in order to function. As many of these structures are intricate, the fact that folding is usually extremely efficient is a remarkable testament to the power of evolutionary biology.

2.11 FAT

Fats are sources of energy in foods. Fats belong to a group of substances called lipids, and come in liquid or solid forms. All fats are combinations of saturated and unsaturated fatty acids.

Saturated fats: These are the biggest dietary causes of high LDL level. Saturated fats are found in animal products such as butter, cheese, whole milk, fatty meals, etc. They are also found in some vegetable oils.

Unsaturated fats: Fats that help to lower blood cholesterol if used in place of saturated fats. However, unsaturated fats have a lot of calories, and so still need to be limited. Most liquid vegetable oils are unsaturated. Two types of unsaturated fats are monounsaturated fats (examples, olive and canola oils) and polyunsaturated fats (examples, fish, corn, and soya beans oils).

2.11.1 FUNCTIONS OF FATS

 Fats supply energy to the body.

 They are needed for the proper functioning of the body.

 Fats are sources of extra storage forms of energy in adipose tissues.

 They help in the absorption and movement of molecules such as vitamins through the blood.

2.11.2 SIDE EFFECTS OF FATS

 Consumption of two much fat is one of the risk factors for cardiovascular diseases.

 Large intakes of polyunsaturated fats increase the risks of certain types of cancer.

2.12 CARBOHYDRATES

Carbohydrates are so named because the carbon, oxygen and hydrogen they contain are generally in proportion to form water with the general formula Cn(H2O)n. They may be classified according to their degree of polymerization and may be divided initially into three principal groups, namely monosaccharides, oligosaccharides, and polysaccharides. Each of these groups may be subdivided on the basis of the monosaccharide composition of the individual carbohydrates. Sugars comprise of monosaccharides, disaccharides, and polyols (sugar alcohols); oligosaccharides include matto-oligosaccharides, principally those occurring from the hydrolysis of starch, and other oligosaccharides, examples, α-galactoside (rafinose, starchose, etc) and fructo-oligosaccharides; the final group is the polysaccharides of which the major component are the polysaccharides of plant cell wall such as cellulose, hemicellulose and pectin.

Carbohydrates have a wide range of physiological functions which are:

 Provision of energy

 Gastric emptying/effects of satiety

 Control of blood glucose and insulin metabolism

 Protein glycosylation

 Cholesterol and triglyceride metabolism

2.13 FIBRE

Dietary fibre or roughage is the indigestible portion of food derived from plants. Dietary fibre consists of non digestible carbohydrates and lignin that are intrinsic and intact in plants. Functional fibre consists of isolated, nondigestible carbohydrates that have physiologic effects in humans. Total fibre is the sum of dietary and functional fibre. Food sources of dietary fibre are divided according to whether they provide (predominantly) soluble or insoluble fibre. Plant foods contain both types of fibre in varying degrees, according to the plant’s characteristics.

 Soluble fibre, which dissolves in water, is readily fermented in the colon into gases and physiologically active by-products, and can be prebiotic and viscous.

 Insoluble fibre, which does not dissolve in water, is metabolically inert and provides bulking, or it can be prebiotic and metabolically fermented in the large intestine. Bulking fibres absorb water as they move through the digestive system, easing defecation.

Dietary fibre can act by changing the nature of the contents of the gastrointestinal tract and by changing how other nutrients and chemicals are absorbed. Chemically, dietary fibre consists of non-starch polysaccharides such as, cellulose, and many other plant components such as resistance starch, resistance dextrins, insulin, lignin, waxes, chitin, pectins, beta-glucans, and oligosaccharides.

CHAPTER THREE

3.0 MATERIALS AND METHODS

3.1 MATERIALS

Soxhlet extractor

Oven

Muffle furnace

Crucibles

Masking tape

Spatula

Measuring cylinder

Whatman filter paper

Kjedahl apparatus

Weighing balance

Aluminium foil

Beakers

Electric heaters

Glass rods

Retort stand

Conical flask

Funnel

Pipettes

Burette

Distillation flask

3.2 REAGENTS USED

Methanol (CH3OH)

Trichloromethane/chloroform (CHCl3)

2,2,4-trimethylpentane (isooctane)

Sulphuric acid (H2SO4)

Boric acid

Hydrochloric acid (HCl)

Nitric acid (HNO3)

Sodium hydroxide (NaOH)

Copper sulphate (CuSO4)

Sodium sulphate (Na2SO4)

Sodium chloride (NaCl)

 Selenium metal

Ammonium molybdate (NH4)6MN7O24.4H2O)

Ammonium vanadate (NH4VO3)

Distilled water

3.3 SAMPLE COLLECTION AND PREPARATION

The celery leaves were bought at Onitsha local market in the month of May, 2018. The leaves were chopped, and put into the refrigerator.

3.4 METHODS:

The proximate analysis was carried out according to the method of AOAC (1990).

3.4.1 MOISTURE CONTENT DERTERMINATION

An empty petri dish was dried in an oven for about 10 minutes and allowed to cool in a desiccator containing calcium chloride for about 20 minutes and then weighed (W1). The fresh celery leaves (2g) was weighed into the petri dish (W2) and placed in an oven at 1050C for 8 hours. It was then brought out, cooled in a desiccator and weighed (W3). The procedure was repeated until a constant weight is obtained. The moisture content was calculated as below:

 x 100

3.4.2 ASH DETERMINATION

Ash represents the inorganic remains after the organic carbonaceous portion and other volatile components have been oxidized and evaporated away. An empty crucible was fire-polished in muffle furnace and allowed to cool in a desiccator containing calcium chloride for 20 minutes and then weighed (W1). Two grams (2g) of the celery was weighed into the crucible (W2) and transferred into muffle furnace and heat at 550oC until the sample is completely ash, the crucible was removed and a drop of water was added to expose the unashed portion. The crucible was placed back in the muffle furnace and heated for more 30 minutes. This was removed and allowed to cool in desiccator after which the crucible with the ash was weighed (W3). The ash content was calculated as below:

 x 100

3.4.3 CRUDE PROTEIN DETERMINATION

The crude celery content of the sample was determined using the macrokjeldahl method of AOAC (1990). The samples will be digested with concentrated sulphuric acid, using copper sulphate and sodium sulphate as catalyst to convert organic nitrogen to ammonium ions. Alkali will be added and the liberated ammonia is distilled into an excess boric acid. The distillate was titrated with hydrochloric acid or sulphuric acid.

Procedure

One gram (1g) of the fresh celery was dried in the oven at 105oC was weighed and transferred into the Kjedahl digestion flask followed by the addition of 3g of a mixture of sodium sulphate and copper sulphate pentahydrate in the ratio 10:1 as catalyst. Four anti-bumping chips were added to prevent sticking of the mixture to the flask during digestion and also to enhance boiling. The Kjedahl flask content was digested with 25ml concentrated H2SO4. The flask was inclined and heated gently at first until frothing ceased, then heated strongly with shakings, at intervals, to wash down charred particles from sides of the flask. Heating was continued until the mixture become clear and free from brown or black colour. This was allowed to cool and the content of the flask made up to 100ml using distilled water. 20ml of this diluted digest was placed in the distillation flask. 50ml of 2% boric acid solution was measured into a conical flask, and few drops of screened methyl red indicator were added into the conical flask. The conical flask and its content were placed on the receiver, so that the end of the delivery tube dips just below the level of the acid. Few pieces of granulated zinc and anti-bumping granules was added to the distillation flask and about 40ml of 40% NaOH solution was run into the flask to make the liquid in the flask alkaline. The content was boiled vigorously until the content of the flask bumps. The distillate was titrated with 0.1N HCl to a purple coloured end point (Vml). The protein content was calculated as below:

 x 100

Crude Protein (%) = %Nitrogen x 6.25

3.4.4 CRUDE FAT DETERMINATION

The crude fat was determined using soxhlet extraction method of AOAC (1999). A 500ml fit round bottom flask was washed and dried in an oven for about 25 minutes and allowed to cool in a desiccator before it was weighed (W1). Five grams (5g) (W) of the celery was weighed and dried in an oven at 105oC. It was then wrapped in a thimble. This thimble and its content were inserted into the extraction column with the condenser. About 350ml of the extracting solvent (n-hexane) was poured into the round bottom flask and fitted into the extraction unit. The flask was heated with the aid of electrothermal heater at 60oC for six hours. Losses of solvent due to heating were checked with the aid of the condenser so that it cooled and refluxed the evaporated solvent. After extraction, the thimble was removed and the solvent salvaged by distillation. The flask and its content were placed on a water bath to evaporate off the solvent. The flask and the residue was transferred to an oven and heated for some minutes to evaporate the remaining solvent and moisture to complete dryness. It was cooled in a desiccator and weighed (W2). The lipid content was calculated as below:

 x 100

3.4.5 CRUDE FIBRE DETERMINATION

The crude fibre was determined using the gravimetric methods of AOAC (1999). The crude fibre method gives an estimation of insoluble and indigestible food residue which remains after which the sample has been treated under prescribed conditions. It was determined by consecutive treatment with light petroleum, boiling dilute sulphuric acid, boiling dilute NaOH; dilute HCl, alcohol and ether. The insoluble residue was collected by filtration, dried, weighed and ashed to collect mineral contamination.

Procedure

The defatted sample (2g) obtained during fat determination was air dried and transferred into a 250ml conical flask. 200ml of 1.25% sulphuric acid was added and heated gently for 30 minutes. The flask was rotated every few minutes, in order to mix the content and remove particles from the side. At the end of the 30 minutes boiling period, the acid mixture was allowed to stand for one minute and then filtered using a filter paper. The filtration was so fast and was completed within 2minutes. The insoluble matter was washed with boiling distilled water until the filtrates is free from acid. The insoluble matter was washed back into the flask by means of wash bottle containing 1.25% NaOH and boiled for 30 minutes with the same precaution as those used in the early acid treatment. At the end of the 30minutes boiling, the mixture was allowed to stand for one minute and then filtered immediately using a filter paper. The insoluble matter was wash with boiling water until no base is detected in the filtrate. The whole insoluble matter was washed with 1% HCl and finally with boiling water until free from acid, it was then washed twice with alcohol and three times with ether. The insoluble matter was transferred into a dried weighed crucible and then oven-dried at 100oC to constant weight. The crucible and its content was ash in muffle furnace at 550oC and re-weighed. The difference between the weight of ash and the weight of insoluble matter gave the weight of the crude fibre. The crude fibre was calculated as below:

    x 100

3.4.6 DETERMINATION OF TOTAL CARBOHYDRATE

This involves the measure of carbohydrate content, usually done conveniently by the difference method:

Total carbohydrate= 100-(% lipid + ash+ moisture + protein) (Yerima and Adamu, 2011).

CHAPTER FOUR

4.0 RESULTS

4.1 Proximate Composition of Apium graveolens.

The proximate composition of Apium graveolens is shown in Table 1. The results were presented in the form of percentage compositions. The ash, moisture, crude protein, crude fibre, total fat and carbohydrate content of the leaf were 5.74%, 79.95%, 1.69%, 1.08%, 1.1%, 10.82% respectively. These results were lower than that of Ashoush et al. (2017), which had the ash, moisture, crude protein, crude fibre, total fat and carbohydrate content to be 20.98%, 88.72%, 19.47%, 19.85%, 2.18%, 36.8%.