ISOLATION AND IDENTIFICATION OF FUNGI ASSOCIATED WITH STORED Sesamum indicum (SESAME SEED) IN SELECTED AREAS IN NASARAWA TOWN

ISOLATION AND IDENTIFICATION OF FUNGI ASSOCIATED WITH STORED Sesamum indicum (SESAME SEED) IN SELECTED AREAS IN NASARAWA TOWN

ABSTRACT

This work was designed to isolate and identify the fungi associated with stored Sesamum indicum (Sesame Seed) in Nasarawa Town. A total of three (3) samples were collected each from Nasarawa Main Market, Student Village and Tammah. Four (4) species of fungi were identified; Aspergillus flauus, Aspergillus terreus, Candida albicuus and Penicillium chrysogenum. The isolates were subjected to comparative morphological analysis using published description in mycological atlas. The result showed that Aspergillus has 67% in Student Village and Tammah Market 33%, where as Candida has 39%, in Student Village 33% in Tammah Market and 28% in Nasarawa main Market and Penicillium has 50% both in Nasarawa main Market and Tammah Market but has 0% in Student Village. Due to the variation in the occurrence of these fungal isolate on the sesame seeds, I wish that government should give urgent attention to stakeholders and farmers that involved in the storage and processing of th Sesame Seeds by providing them facilities, awareness and quality control measures that includes routine testing for fungal contamination and mycotoxin levels in the stored Sesame Seeds.

CHAPTER ONE

1.0                                                            INTRODUCTION

1.1       Background of the Study

Sesame seed (Sesamum indicum) is a flowering plant in the genus Sesamum, also called benne seed and ridi in Hausa. Numerous wild relatives occur in Africa and a smaller number in India. It is widely naturalized in tropical regions around the world and is cultivated for its edible seeds, which grow in pods. World production in 2018 was 6 million tonnes, with Sudan, Myanmar (A Country in Asia) and India as the largest producers.

Sesame seed is one of the oldest oil seed crops known, domesticated well over 3,000 year ago. Sesamum has many other species, most being wild and native to sub-Saharan Africa. S. indicum, the cultivated type, originated in India. It tolerates drought conditions well, growing where other crops fail. Sesame has one of the highest oil contents of any seed. With a rich, nutty flavor, it is a common ingredient in cuisines around the world. Like other seeds and foods, it can trigger allergic reactions in some people.

Sesame seed production in 2018, crops/world regions/production quantity from pick lists. UN Food and Agriculture Organization Corporate Statistical Database (FAOSTAT). 2020. Retrieved 15 November 2020.

Sesame is considered to have born nutritional and medicinal values. The seed are used either decorticated or whole in sweets. Such as Sesame bars and halve. In baked products, or milled to get high-grade edible oil or Talini an oily paste (Bedigian, 2004), Tahini is widely used in foods in the Middle East. Sesame seed contains two lignans, sesamin and sesamolin. After roasting sesame seeds, sesamolin is converted to sesamol. Sesamol has been found to have anti-oxidative effects and to induce growth arrest and apoptosis in cancer cells. In recent times, the anti-photo-oxidant activity of sesamol for oil has been reported to be due to the scavenging of single singlet oxygen. Sesamol has a phenolic and a benzodioxide group in its molecular structure. The phenolic groups of molecules are generally responsible for the anti-oxidant activity of many natural products. On the other hand, benzodioxide derivatives are widely distributed in nature and have been shown to possess anti- tumor, anti-oxidant and many other biological activities.

It is noteworthy that in recent times sesame seeds have been found to contain immunoglobulin E (IgE) – mediated food allergens, with research reports from France (Agne et al.,2003), Israel (Dalal et al., 2002), Italy and the U.S. The more prevalence of sesame seed allergy is probably attributed to the wider and expanding use of sesame seed in baked products and fast foods (Pastorello et al., 2001).

Sesame is reputed in folk medicine in Africa and Asia. All parts of the plant are useful however in the South-Western Nigeria, decoction of the leaves is used for the treatment of bruised or erupted skins, catarrh and eye pains. Warm water leaves infusion is used to gargle and treat inflamed membranes of the mouth. But, the decoction of both leaves and roots has been found to be effective against chicken pox and measles (anti-viral) and used as hair shampoo for Taeniacapitis (antifungal properties). Sesame seed oil has been used as healing oil for thousands of years and also enjoyed by humans since the dawn of civilization. In Nigeria, three species, which include S. alatum (Thonn), S. indicum L. and S. radiatum  Schum & Thonn, are widely cultivated for different purposes. However, in Tiv and Idoma areas of Nigeria’s Benue state, two breeds of Sesame -the Sesame radiatum and Sesame indicum are usually cultivated mainly for their seeds and leaves. They also constitute the staple food consumed locally in these areas and also especially in South-West and Middle Belt areas of Nigeria where it is richly cultivated by local subsistence farmers and this may account for the high fecundity of the people especially among the adult male population. The seeds could be consumed either through its oil, roasted or as animal feeds (Akpan-Iwo et al., 2006).

Sesame is attacked by many fungi and bacteria such as F. oxysporum, F. sesame and M. phaseolina, Salmonella spp. These fungi and bacteria may cause seed deterioration with a reduction in quality and quantity. Water activity is an important ecological factor for the growth of microorganisms such as fungi since they contaminate various foods at a wide range of water activity. The need for a meaningful term to describe the behaviour of fungi in the environment with reduced moisture helped to establish the term water activity. (Labuza et al., 2010), reported earlier that reducing water activity below 0.7 prevented food from fungal spoilage. Moreover, some of the contaminated fungi such as Fusarium, Aspergillus and Penicillium may produce several mycotoxins. One of the most important mycotoxins is aflatoxins which are produced by several species of Aspergillus (Labuza et al., 2010).

1.       Statement of the Problem

Deterioration of grain such as sesame seed by microorganisms is determined by several factors which can be classified into four main groups; Intrinsic factors (those which depend on the characteristic of the growth substrate), extrinsic factors (those imposed from the outside), processing factors (those resulting from the agronomic practices and food processing, which primarily modify the composition of the microflora) and the implicit factors (those depending on the particular dominant microbial flora that initially develop in response to the intrinsic, processing, and extrinsic factors).

1.3       Justification for the Study   

Spoilage of sesame seed mostly occur as a result of moisture in the cereals during storage and storage of moist cereals is quite common in temperate climatic regions. These fungi may cause seed deterioration with a reduction in quality and quantity. Water activity is an important ecological factor for the growth of microorganisms such as fungi since they contaminate various foods at a wide range of water activity. The need for a meaningful term to describe the behavior of bacteria in the environment with reduced moisture helped to establish the term water activity (Breene et al., 1998).

1.4       Aim and objectives of the Study

The aim of this study was to isolate and identify the fungi species associated with stored sesamum indicum (sesame seed) in some selected areas in Nasarawa metropolis. The specific objectives were to:

1. Isolate the fungi associated with the spoilage of stored sesame seeds in Nasarawa metropolis.
2. Identify the fungal isolates using comparative morphological analysis.
3. Determine the percentage occurrence of the different fungal isolates.