Proximate And Phytochemical Analysis Of Soursop

Introduction

1.1 Background of the Study

Edible wild indigenous plants become an alternative source of food with high potential of vitamins, minerals and others interesting elements particularly during seasonal food shortage (Umaru et al., 2007). Wild fruits are also known to have nutritional and medicinal properties that can be attributed to their antioxidant effects and they can be used to fortify staple foods particularly for malnourished children (Barminas, 1998). There is much evidence that the quality and composition of food may contribute to present and future health benefits of young children.

According to the World Health Organization, malnutrition is the cellular imbalance between the supply of nutrients and energy and the body’s demand for them to ensure growth, maintenance, and specific functions (Tierney et al., 2010). The term protein-energy malnutrition (PEM) applied to a group of related disorders that include marasmus, kwashiorkor, and intermediate states of marasmus-kwashiorkor (Tierney et al., 2010). The most common form of malnutrition in Africa is protein energy deficiency affecting over 100 million people, especially 30 to 50 million children under 5 years of age (Jildeh et al., 2010). Some legumes such as soybean, bean, and peanut, are important sources of protein and can therefore help to increase the protein intake of the diet of population. However, the low-income group, especially in rural areas, sometimes cannot afford these protein foods. Soursop (Annona muricata) belongs to the family Annonaceae, and it is wide spread in the tropics and frost–free subtropics of the world (Samson, 1980). The soursop plant is cultivated mainly in home gardens. The tree yields up to 10 tons/ha and each fruit weighs 0.5 to 2 kg (National Academy of Science, 1978). The fruit is compound in and covered with reticulated, leathery-appearing but tender, inedible bitter skin from which protrude few or many stubby, or more elongated and curved soft, pliable “spines”. The skin is dark-green in the immature fruit, becoming slightly yellowish-green before the mature fruit is soft to the touch. In aroma, the pulp is somewhat pineapple-like, but its musky, subacid to acid flavor is unique (Schultes and Raffauf, 1990).

It is indigenous to most of the warmest tropical areas in South and North America including Amazon, A. muricata has become naturalized in many countries, and now has a wide distribution throughout tropical and subtropical parts of the world. The fruit makes an excellent drink or ice cream after straining. Several studies have described the medicinal purposes of Annona muricata and have outlined the social history of the plants’ use (Ayensu, 1981). All parts of the A. muricata tree are used in natural medicine in the tropics including the bark, leaves, root and fruit-seeds. The crushed seeds are used as a vermifuge and anthelmintic against internal and external parasites and worms. The bark leaves and roots are considered sedative, antispasmodic, hypoglycemic, hypotensive, smooth muscle relaxant and nervine and a tea is made for various disorders for those purposes (Holdsworth, 1990). Many bioactive compounds and phytochemicals have been found in A. muricata and its many uses in natural medicine have been validated by many scientific researches (Heinrich, 1992; Sundarrao, 1993). Generally the fruit and fruit juice is taken for worms and parasites, to cool fevers, to increase mother’s milk after childbirth (lactagogue), and as an astringent for diarrhea and dysentery. Due to the fact that the fruit has a wide distribution throughout tropical and subtropical parts of the world and mainly in developing country, the aim of this study was to investigate the physicochemical, the nutritional potential and mycoflore associated with Soursop (Annona muricata L.) from Benin. An emphasis has been placed on its use as food supplement against Protein-Energy Deficiency. For its valorization, the physicochemical and microbial changes in soursop puree which has been pasteurized at optimum thermal condition (Umme et al., 1997) were also investigated. This study also aims to make available an improved industrial technology for the production of soursop puree, which retains all the nutritional potential of the fruit during storage.

The bark, leaves, fruit, roots, and fruit seeds of the soursop tree are known since long for various medicinal uses. The fruit and juice is used against worms and parasites, to cool down fevers, to increase lactation after childbirth. The seeds can be crushed and then used against internal or external parasites, head lice, and worms[6].The tea prepared from the leaves are used as a sedative and a soporific (inducer of sleep) in the West Indies and Peruvian Andes. This infusion is also used to relief pain or for antispasmodic purposes. For liver problems a leaf tea is used in the Brazilian Amazon[7]. Traditionally it is used in medicinal herbal drugs to cure various diseases such as for diarrhea (fruit), cough, hypertension, rheumatism, tumors, cancer, asthma, childbirth, lactagogue (fruit), malaria, tranquilizer, skin rashes, parasites (seeds), worms (seeds), liver problems, arthritis (used externally) etc[8]. It contains a variety of components which attribute to the various biological activities. The roots and bark can be of aid for diabetes, but can also be used as a sedative. The purpose of the present review is to highlight the various traditional uses, phytochemistry and pharmacological reports on Guyabano (A. muricata).

1.2 Problem Statement

There is dearth of information on the health beneficial constituents of the edible and non-edible portions of soursop fruits in Nigeria to make any substantial claim for their optimal use (WHO/FAO, 2004; Abebrese et al., 2007). Endeavours in research works to enhance the commercial production and subsequent value addition of fruits, have been skewed towards the hackneyed ones leaving no room for variety for consumers. This challenge is exacerbated by recent policy that focuses on the common few fruits such as pineapple, citrus and pawpaw in a bid to diversify the nation’s agricultural export base to ensure food security through non- traditional export commodities (Aboagye et al., 2006; FASDEP II, 2007).

1.3 Justification

Investigating key parameters for assessing the health potential of the underutilized fruits will complement literature in making known the potential of the soursop as well as provide a stepping-stone for further research works in other uses of the fruits.

Currently, consumers choose diets based on the associated nutritional and health benefits instead of taste (Katan and De Roos, 2004) and it is postulated that the published information obtained on the not-so-known fruits will offer diversity to the health-conscious consumer. This will curtail the challenges of monotony associated with fruit consumption and poor availability associated with seasonal variations. The knowledge obtained from the study, will also aid policy-makers in making informed decisions in the agricultural sector aimed at broadening the nation’s food security basket.

1.4 Objectives

The overall aim of this research is to carry out a proximate and phytochemical analysis of soursp..

Specifically, the study seeks to:

1. Determine the dietary fibre fractions and proximate composition of the edible portions of soursop
2. Assess the phytochemical composition of soursop.