EFFECT ON BIOLOGICAL PRESENTATION ON SPILOTAGE OF ORGANISMS OF FERMENTED MAIZE (OGI)

ABSTRACT

In Africa, various foods go through fermentation such as porridges, beverages (both alcoholic and non-alcoholic), meat, breads, pancakes, fish, vegetables, tubers, legumes, dairy products, and condiments. One of the most prevalent fermented cereals is fermented porridge. In Nigeria, fermented cereals, particularly maize, are used to make fermented porridge, local brew (busaa), and beer through grain fermentation. This  study aims to assess and identify particular microorganisms engaged in the fermentation process to create a starter culture and determine the longevity of fermented maize flour. The raw ingredient known as 'ogi' was procured from the renowned Oyingbo market and subsequently subjected to the process of cooking, resulting in the transformation of its physical state into a more fluid consistency, resembling that of a thin porridge. Upon conducting the biochemical tests, it has been ascertained that the organisms designated as OB 6 and OB7 correspond to Bacillus megaterium and Bacillus subtilis, respectively. The examination of amylase activities was conducted across a range of temperatures and pH levels. Based on the data presented, it has been observed that the organisms achieved their maximum efficiency at a temperature of 40oC. Regarding the activity of amylase in Bacillus megaterium, it has been observed that the optimal pH for this particular enzyme is 4. Conversely, in the case of Bacillus subtilis, the ideal pH for amylase activity is 2. Upon subjecting the amylase to a thermal treatment at a temperature of 80 degrees Celsius for a duration of 10 minutes, a noteworthy reduction in the enzymatic activities responsible for the degradation of starch by these organisms was observed.

 

CHAPTER ONE

INTRODUCTION

Background of the study

The word fermentation originates from Latin, Fervere, and was described by Louis Pasteur as life without air. Described as a metabolic process that extracts energy from organic compounds without requiring an external oxidising agent (Bourdichon et al., 2012). Fermentation is widely used across various regions, including Africa, to create a variety of commercial and homemade goods. For centuries, Africa has been a hub for producing a wide range of traditional fermented foods, particularly lactic acid fermented foods, as documented by Franz et al. (2014). In Africa, various foods go through fermentation such as porridges, beverages (both alcoholic and non-alcoholic), meat, breads, pancakes, fish, vegetables, tubers, legumes, dairy products, and condiments. One of the most prevalent fermented cereals is fermented porridge. In Nigeria, fermented cereals, particularly maize, are used to make fermented porridge, local brew (busaa), and beer through grain fermentation.

Utilising fermentation can expand the range of products that can be made from maize. In Nigeria, many maize flour products go through natural wild fermentation, as described by Assohoun et al. (2013). One of these is maize flour that is locally roasted and commonly known by its local name Ogi. This product is widely embraced in the Western region of Nigeria and serves various purposes. Ogi is primarily produced through wild fermentation, resulting in a diverse range of quality. Engaging in this process can lead to health hazards due to its lack of hygiene and time-consuming nature, resulting in inconsistent product quality (Abegaz, 2013; Kivanç and Funda, 2017).

The study aimed to identify and describe the fermentative bacteria involved in this process to enhance its efficiency and ensure consistent quality. Allowing natural bacteria in a product to kickstart the fermentation process is known as wild or spontaneous fermentation (Chaves-Lopez et al., 2014). When maize flour products undergo spontaneous fermentation, a combination of microorganisms work together to influence the final product quality under certain conditions (Okoronkwo, 2014). Creating the optimal environmental conditions is crucial for the organisms to flourish and multiply, allowing the bacteria and yeast in the product to regulate the fermentation process. Thus, the outcomes will be influenced by the species that are predominant in the fermentation process. Spontaneous fermentation can result in exceptional quality and exquisite flavour. However, there may be instances when it doesn't work as expected, even under perfect circumstances. This occurs because spontaneous fermentation is inherently unpredictable (Nwachukwu et al., 2010), and it also requires a longer duration.

​​​​​​​Statement of the Problem

Fermented maize flour is commonly produced in various regions of Nigeria for various purposes such as snacking (known as Ogi) and as an ingredient in local alcoholic brew like busaa in Kenya. Despite the product's popularity among consumers and its claimed shelf-life of over 3 months, its preparation involves spontaneous fermentation relying on natural inoculum from the environment. This has led to inconsistencies in product quality without a set standard. The fermentation time ranges from 4 to 6 days, leading to variations in the product's quality. There is still no standardisation in the production of this product, and its actual shelf-life remains a mystery. The product's sensory characteristics vary due to the unconventional preparation methods. The lack of extensive knowledge regarding its production has hindered the industrial production and commercialization of this product as a functional food and source of healthy probiotic bacteria. Lactic acid bacteria have been utilised in the preservation of fermented and cooked maize flour products for an extended period. Several strains have been identified as effective against pathogens and spoilage organisms associated with these products. On the other hand, no research has been conducted on utilising pure strains of LAB starter culture to enhance the quality of Ogi (maize product). Spontaneous fermentation results in a range of quality attributes and involves a diverse group of microorganisms, but only a select few actually impact the final product quality (Abegaz, 2013). Hence, the present study aims to assess and identify particular microorganisms engaged in the fermentation process to create a starter culture and determine the longevity of fermented maize flour.

​​​​​​​Objectives

The aim of this study is:

1. To contribute to scare literature on spilotage of organisms of fermented maize (ogi).
2. To examine effect on biological presentation on spilotage of organisms of fermented maize (Ogi).

Justification of the Study

The product, Ogi is produced through spontaneous fermentation, which results in various quality attributes. Wide spectrum of microorganisms causes spontaneous fermentation yet only a few determine the product quality. Isolation, characterization and identification of these microorganisms sought to establish particular environmental conditions that specific microbial communities will determine product quality, thus making the production process more predictable. In order to develop bio-preservation strategies for Ogi, suitable LAB species must be identified for use in the enhancement of safety and quality of Maize products.

The antagonistic properties of LAB originating from the production of metabolites that are antimicrobial such as organic acids (lactic and acetic), hydrogen peroxide, and antimicrobial peptides (bacteriocins). The study sought to improve the quality of Ogi through the optimization of the fermentation process through use of a pure starter culture in order to ensure a uniform product in terms of its quality attributes. This can greatly contribute towards the modernization of techniques of production of fermented maize flour based products. The study will also avail traditional fermented products to be used as nutrient sources when there is food insecurity and improve the quality of fermented Ogi in terms of nutrients content, thus provide nutritional benefits to its consumers. The pure cultures will also encourage the adoption of this process outside the Western region of Nigeria thereby encouraging diversification of maize flour products.