Thesis Abstract

Abstract
Parkia biglobosa, commonly known as African locust bean, is a popular food ingredient in West Africa due to its unique flavor and nutritional value. However, the spoilage of Parkia biglobosa by fungi poses a significant challenge to its quality and safety. In this study, we aimed to detect and identify the fungi species involved in the spoilage of Parkia biglobosa to better understand the factors contributing to its deterioration. Samples of spoiled Parkia biglobosa were collected from local markets in Nigeria and Ghana. The fungi present in the samples were isolated using standard microbiological techniques and identified through morphological and molecular methods. The genetic analysis involved sequencing the internal transcribed spacer (ITS) region of the fungal DNA to accurately determine the species involved in the spoilage. Our results revealed the presence of various fungal species in the spoiled Parkia biglobosa samples, including Aspergillus niger, Penicillium chrysogenum, and Fusarium oxysporum. These fungi are known for their ability to produce mycotoxins and enzymes that can degrade the protein and lipid content of the food, leading to spoilage. The identification of these fungi species provides valuable insights into the spoilage mechanisms of Parkia biglobosa and highlights the importance of proper storage and handling practices to prevent fungal contamination. Furthermore, our study found that the fungal diversity in spoiled Parkia biglobosa samples varied between different regions, with some species being more prevalent in Nigeria compared to Ghana. This regional variation suggests that environmental factors, such as temperature and humidity, may influence the growth of specific fungi species in Parkia biglobosa. Overall, our findings contribute to the understanding of fungal spoilage in Parkia biglobosa and emphasize the importance of implementing quality control measures along the production and distribution chain to ensure the safety and quality of this important food ingredient. Future research could focus on developing strategies to inhibit the growth of spoilage fungi in Parkia biglobosa through the use of natural preservatives or modified storage conditions.

Thesis Overview

INTRODUCTION

The seed of locust beans (Parkiabiglobosa) plant found growing in the Savannah Africa provides one of the popular seasonings in African diet. The nutritious and delicious food spice is popularly called “ogiri” in Igbo, “iru” in Yoruba and “dawadawa” in Hausa in Nigeria. It is heavily consumed in Nigeria, Ghana, Sierre Leone and Togo (Odunfa, 1985). It serves as source of protein for most of the people whose protein intake is low due to high cost of animal protein sources.

The African locust bean tree, Parkiabiglobosaare perennial trees legumes which belongs to the sub-family mimosoideae and family leguminosae (now family fabaceae). They grow in the Savannah region of West Africa up to the southern edge of the Sahel zone 13°N (Campbell-Platte, 1980). The plant occurs in a wide range of Natural Savannah woodlands and ithas the capacity to withstand drought conditions because of its deep tap root system (Nwadiaroet al., 2015). A matured locust bean tree (20-30years) can bear about a ton and above harvested fruits. From experience, the tree can start to bear fruits from 5-7 years after planting (Musa, 1991). The African locust bean tree grows to about 20m in height and has bark evergreen pinnate leaves. Its fruit is a brown leathery pod of about 10-30cm long and contains gummy pulps of an agreeable sweet taste, in which lie a number of seeds. It is important indigenous multipurpose fruit tree. Parkiabiglobosa tree plays vital ecological roles in recycling of nutrients from deep soil, by holding soil particles to prevent soil erosion with the aid of its roots. It also provides shade where it is found (Campbell-Platte, 1980). This tree is protected by peasant farmers and rural dwellers for its many benefits. Its wood is a source of fuel energy. It helps to enrich the soils nutrient.

The most important use of African locust bean is found in its seed which is a legume, although it has other food and non-food uses especially the seeds which serve as a source of useful ingredients for consumption (Campbell-Platte, 1980). It has been reported that the locust bean is rich protein, carbohydrate, soluble sugars and ascorbic acid. The cotyledon is very nutritious, has less fibre and ash content. The oil content is suitable for consumption since it contains very low acid and iodine contents. The oil has very high saponification and hence would be useful in the soap industry (Alabiet al., 2005). It has also been reported that the husks and pods are good for livestock (Douglass, 1996; Obiazoba, 1998). The locust bean tree is also important in medicinal practices in treatment of aliments such as bronchitis, pneumonia, malaria, diarrhoea and as poison for sore eyes (Farombi, 2003).

Although microorganisms of all groups including bacteria, protozoa, algae, viruses, fungi together with insects and rodents play significant role in food deterioration, the most active and more versatile organisms that affect locust bean seeds and its products causing spoilage when stored are species of bacteria and fungi (Omafuvbeet al., 2000). They can occur on growing crops as well as harvested commodities leading to damage ranging from rancidity, odour and flavour changes and germ layer destruction (Cutler, 1991). In a study to identify the bacterial and fungal flora of deteriorated and maggot infested samples of fermented locust bean seeds, the isolated fungal species were identified as Aspergillusniger, Aspergillusflavus, Penicillium, Rhizopus and Candidaspecies. Parkiabiglobosa seeds are subject to degradation induced by diverse organisms including fungi which are among the most active microorganisms in these processes (Popoola and Akueshi, 1985). Microorganisms associated with fermented locust bean seeds have been widely studied (Odunfa, 1981; Ikenebomehet al., 1986; Odunfa and Oyewole, 1986; Ogbadu and Okagbue, 1988). Bacilli and Staphylococci were observed to dominate the fermentation together with a number of fungal species causing deterioration of this especially in storage in Northern Nigeria.

1.1       AIM

• This study is aimed at DETECTING THE FUNGI SPECIES INVOLVED IN PARKIABIGLOBOSASPOILAGE.

1.2       SPECIFIC OBJECTIVES

• To isolate and identify fungi associated with locust beans (Parkiabiglobosa).
• To determine the pH, moisture content and titratable acidity of locust beans.