PHYTOCHEMICAL AND MINERAL COMPOSITION OF PAWPAW (PAPAYA) SEED

PHYTOCHEMICAL AND MINERAL COMPOSITION OF PAWPAW (Papaya) SEED

CHAPTER ONE

1.0     Introduction

Pawpaw is a common fruit consumed in the world. Pawpaw belongs to

Kingdom:             Plantae

Order:                   Violates

Family:                 Caricaceae

Genus:                  Carica

Species:                Caricapapaya

Pawpaw is a spermatophyte (seed plant). So there are hardly any true varieties, rather there are types which are classified based on fruit size, shape, flesh colour, flavor and similar characteristics.

Caricapapaya is a single stem plant that grows from 5 – 10m and is a about 1 foot in diameter. The stem or trunk is simple, erect, without branches and gradually tapers from the base to the to the summit where it terminates its entire length is thickly covered with scars of fallen leaves and fruits. The leaves are large 50 – 70cm diameter, alternate, close together, deeply palmatelydivided into 5 – 7 irregular.

Caricapapaya is polygamous, with three primary sex types, bisexual, male and female. Bisexual plants produce more than one kind of flowers (male and female) at the same time. The male flowers are borne on long pedundedracemes while the females are solitary and axillary on short stalks and consists of a small, 5 – parted Calyx, 5 – twisted pale yellow petals and a large ovary. Caricapapayais a non-seasonal plant bit thrives best during dry season (www.hawaiipapaya.com).

Papaya is a fruit of the plant Caricapapaya. The fruit is round, oblong or pear-shaped to about 45 cm and below. The fruit is irregularly ovoid, with 4 – 6 rib-like projections, pulpy and enclosing numerous blackish seeds. When unripe, the fruit appear green and on ripening yellow-orange. The fruit is ripe when it feels soft (like ripe avocado). The fruit taste is vaguely similar to pineapple and peach. The flesh is yellow, orange or red (Rahmat et al, 2009).

Papaya flesh has been recorded to contain high nutritive value, nutritional value per 100g recorded for papaya flesh shows that it contains 9.81g carbohydrates which comprise of 5.90g sugar and the dietary fibre. Fat is 0.14g while protein content is 0.01g

IU/100g) 6%, vitamin E (276 IU/100g) 3%, Thiamine (0.04 riboflavin (0.05mg) 3%, niacin (0.338mg) 2% vitamin B6 8% vitamin C (61.8Ug) 103%.

Papaya also showed high mineral content. Potassium (275mg) 5% has the highest value while calcium is (24mg) 2% Magnesium (10mg) 3%, phosphorus (5mg) sodium (3mg) 0% and the heavy metal iron (0.10mg) 1%. This data gives a valuable reason why papaya is greatly consumed and the seeds discarded due to absence of reliable data of its nutritional composition.

Papaya seed is one of the seeds considered waste by individuals who consume the flesh. Papaya seed are small, blackish when matured and whitish when not matured. The seed is enclosed in a sac of liquid. Within the sac is a hard and rough epicarp which encloses the testa. The testa contains varying quantities of minerals and nutrients. This suggests that the seed has important nutrients. This suggests that the seed has important nutritional properties and can be useful in the treatment of diseases and ill health.

A study of the nutritional, mineral, phytochemical, fatty acid and amino acid compositions of this seed, behevably will open an avenue to a wider utilization of the seed. This project work was designed to undertake such study with hope that findings will reveal a lot of potentials for utilization of papaya seeds.

Minerals

Minerals are substances that are naturally present in the earth’s crust and are not formed by animals and plants. Minerals occur in food both in organic and inorganic compounds. The major organic compounds includes carbohydrates, phosphates, chlorides and sulphates of sodium, calcium, potassium and magnesium (Onwuka, 2005). Minerals make up fourteen out of the total nutrients needed for human nutrition. These minerals includes calcium, chlorine, cobalt, copper, fluorine, iodine, iron, magnesium, sodium, phosphorus and sulphur (James, 1996).

Phytochemicals

Phytochemicals are chemical substances that occur naturally in food. Most phytochemicals are beneficial to health while some others are not and are considered food toxicants. Phytochemicals like alkaloids, tannins, saponins and flavonoids are of medical importance and are commonly used in herbal medicine. Okwu, (2005) reported that isolated plant alkaloids and their synthetic derivatives are known for their analgesic, antispasmodic and antibacteriacidal effects.

Some other phytochemicals like cyanogenic glycoside (HCN), Phytate and trysin inhibitor are considered food toxicant. Some of these compounds occur naturally in foods, others probably remain undiscovered but generally, the cause signs or symptoms of toxicity in animals (Onwuka, 2005).

Uses of Pawpaw (Papaya) Seeds

Although, papaya seeds are considered as waste, they are useful in most aspects.

1. Papaya seeds are rich in an enzyme called papain, a protease which is used in tenderizing meat and other protein.
2. Papaya seeds could be used as an effective antibacterial agent for Escherichia coli, Staphylococcus aureus, Salmonella typhi, although further research is needed before advocating large scale therapy (Rahmat et al., 2009).
3. Papaya seed extracts may be nephron protective (protects the kidney) in toxicity induced kidney failure (hawaiipapay.com).
4. Papaya seed extracts a real dissolving or digestive action on nitrogenous substances. This action is obtained in aqueous solution. Note that alcohol renders that extract inert.