LACTIC ACID BACTERIA ASSOCIATED WITH SELECTED FERMENTED BEVERAGES

 ABSTRACT

A total of 4 isolates of lactic acid  bacteria (LAB) were isolated from selected Nigeria Beverages that were gotten from a local market in Umuahia, Abia State.

The isolation and characterization of lactic acid bacteria responsible for the fermentation of kunu- zaki, burukutu and Ugba   were studied in order to access their use as starter culture. Representatives of the lactic acid bacteria were isolated at 12hours interval during the course of fermentation characterized and identified using morphological, physiological and biochemical examination. Changes in pH, titratable acidity, LAB counts were also investigated during the fermentation of the three cereals at different fermentation time (12hrs, 24hrs and 48hrs)

 . The  isolates  obtained  were  accessed  to  have  some  level  of  starter  culture.  Based on the  comparative performance of single isolates. Isolates identified are lactobacillus plantarum, lactobacillus brevis lactococcus lactis, Enterococcus Species. Results indicates a predominance of lactobacilli among isolates. These results suggested that LAB isolates from selected Nigeria Beverages have very good potential to be used as probiotics.

TABLE OF CONTENTS

ABSTRACT

CHAPTER ONE

1.0     Introduction

1.1     Aim and Objectives

CHAPTER TWO

2.0     Lactic   Acid Bacteria

2.1     Importance of Lactic Acid Bacteria

2.1.1  Protection against Various Diseases

2.1.2  Therapeutic Potential

2.2     Traditional Fermented Foods

2.2.1  Ogi

2.3     Lactic Acid Bacteria as A Starter Culture

2.3.1  Pito

2.3.2  Kunu-Zaki

2.3.3  Burukutu

CHAPTER THREE

3.0     Materials and Methods

3.1    Collection of Samples

3.2     Sterilization of Materials

3.3     Identification of Lactic Acid Bacteria

3.3.1  Gram Staining

3.3.2  Biochemical Test

3.3.2.1 Catalase Test

3.3.2.2 Citrate Test

3.3.2.3 Indole Test

3.3.2.4 Sugar Fermentation Test

3.4     Bacteria Isolation and Purification

3.5     Characterization and Identification Of Organism

CHAPTER FOUR

4.0     Results

4.1     Distribution of Isolates

CHAPTER FIVE

DISCUSSION, CONCLUSION AND RECOMMENDATION

5.1     Discussion

5.2     Conclusion

5.3     Recommendation

References

LIST OF TABLES

Table 4.1:       Lactic Acid Bacteria count of some fermented Beverages

Table 4.2:        Cultural description and Biochemical Characteristics of the Isolate

LIST OF FIGURE

Figure1: Shows a schematic, unrooted phylogenetic tree of the lactic acid bacteria.

 CHAPTER ONE

1.0       INTRODUCTION

Microorganisms have been used to produce food for thousands of years. Fermented foods are not only perceived as pleasant-tasting but the acids produced as a by-product of microbial metabolism inhibit the growth of man spoilage organism as well as food- borne pathogen.

Thus, fermentation historically has been and continues to be, an important method of food preservation, particularly when modern convenience such as refrigeration are lacking. High level fermentation are difficult to achieve and are not predictable in terms of length of fermentation and quality of products. Unwanted products could be achieved at the end of the fermentation (Nout, 1992). To achieve a good fermentation products, the most predominant microorganisms found in an acceptable product are isolated and purified according to Marshall, (1993).

Lactic acid bacteria  (LAB) helps in preserving the food and are of significant importance to food industries due to their generally regarded as safe status (GRAS) (Tassell and Miller, 2011). The probiotic activity of LAB makes it a good probiotic organism (Mishra and Sharma, 2014). Either the probiotic has been given as a supplement or as an active component of medication; it should be capable of surviving through the passage of digestive tract along with proliferation in the gut. Benefits of the probiotics must be exerted on the host through growth and metabolic activities in the human body.

Kunu-zaki is a millet based non-alcoholic fermented beverage widely consumed in the  northern parts of Nigeria. This beverage is however becoming more widely consumed in the southern Nigeria, because of the refreshing taste (FAO, 1996)

Burukutu is one of the indigenous alcoholic beverages and is produced mainly from the grains of guinea corn (Sorghum vulgare and sorghum bicolor). Sorghum grains are steeped in water overnight, washed and excess water drained (Kolawole et al, 2007). Microorganisms are needed during the fermentation process but a few usually determines quality of the end products. If favourable environmental condition is allowed, a particular community of microbes can determine the quality of a specific food (Kolawole, 2007). Isolation and characterization of lactic acid bacteria with a selection of starter cultures that are adapted to cereal based production would be important. This can help to develop a starter culture and devise a means of affordable technology.

Pito is a fermented alcoholic beverage which is traditionally brewed from sorghum or maize malts. It has a characteristic sour taste and is slight heavy in the mouth during drinking. It is a fermentation product of mixed cultures of yeast, mould and lactic acid bacteria, all of which may be alive and active when the product is consumed. It is drunk mainly along the West Coast of Africa especially in Nigeria. Pito, like most other local beers in Nigeria, is still produced on a small scale with traditional and primitive equipment and by people that have no scientific know-ledge of the process and have little regard for hygiene. The production process renders the brew very susceptible to contamination by pathogenic organisms during production.

Lactic acid bacteria (LAB) are responsible for a great diversification in the flavor and texture of food products due to their fermentation of food raw materials. However, in some circumstances they can be responsible for food spoilage.  Food fermentation technology, along with drying and salting, is one of the most ancient food-preserving techniques known to humans. Fermented foods are less perishable than the original raw materials, their nutritional value may be enhanced, and the safety of these foods may be improved due to the inhibition of pathogenic bacteria by the low pH and the presence of  organic acids and antimicrobial  compounds.  The ubiquity of LAB in nature often results in opportunistic inoculation of food raw materials. Humans have, since prerecorded times, aided such natural events by purposely adding a portion of previously fermented food to the new batch of raw materials (so-called ‘back-slopping’) in order to promote successful fermentation. In addition, specific traditional technologies often lead to the dominance of particular types of LAB, which gives the product special characteristics.

Today, many traditional fermentation technologies have been industrialized and form large commercial enterprises. Examples of these are the production of cheese and other fermented dairy products, fermented sausages such as salami, and fermented cabbage – sauerkraut. LAB are only weakly proteolytic and lipolytic, which is also important since breakdown products from protein and fat are often organoleptically unpleasant in high concentrations. LAB also inhabit  the  mucous  membranes  of  the  intestinal  and  reproductive  tracts  of  humans  and animals and incorporation of selected strains into certain fermented foods has gained increasing interest in recent years. LAB has a reputation of being ‘generally recognized as safe’ (GRAS). However, some species are pathogenic and the recent developments in the field of probiotics have brought safety aspects of LAB into focus. Aside from the known pathogens, LAB is rarely isolated from disease and in almost all cases is associated with underlying illness which increases the susceptibility of the host. (Caplice and Fitzgerald,1999).

The lactic acid bacteria (LAB) are isolated from various food matrices and those isolates with better performances and high competitiveness are used as probiotics. The probiotics are live organisms that confer health benefits on the host when consumed in adequate amounts, by bringing the microbial balance in the system. The use of probiotics in animal infections, especially in the gastrointestinal and vaginal tract, has been extensively studied. They are proficient in inhibiting the growth of pathogenic organisms through different mechanisms such as adherence to epithelial cells, modulation of the immune system, and secretion of antimicrobial compounds. This proves their ability in the bio-preservation of food and can be used as starter culture in the fermentation process under controlled conditions. Therefore, the isolation and characterization of LAB from different traditional fermented foods and products have gained research interest in recent years.

1.1       AIM AND OBJECTIVES

The aim of this study is to isolate and Characterize Lactic Acid Bacteria from selected Nigerian beverages Kunu, Brukutu, and Pito.

OBJECTIVES:

    i.           To isolate and identify Lactic Acid Bacteria from selected Nigerian Beverages ( Kunu-Zaki, Brukutu and Pito).

   ii.           To Identify Lactic Acid Bacteria

 iii.           To characterize the isolated Lactic Acid Bacteria using morphological and physiological Technique.