ABSTRACT
This study was aimed at the isolation and identification of proteolytic lactic acid bacteria from indigenous fermented foods. 10 grams of each of the samples (Ugba, Kunu, Yoghurt and Ogi) were aseptically added into 90 ml of sterile 0.9% NaCl. From this study, a total of 5 species were isolated and they are Lactobacillus plantarum, Enterococcus spp., Lactobacillus brevis, Lactobacillus lactis and Streptoccus spp were all isolated. All of isolated bacterial strains showed the proteolytic activity on skim milk agar. Among them, Enterococcus spp has the highest proteolytic activity of 23.0mm as indicated by the widest clear zone while Lactotococcus lactis has the least proteolytic activity of 17.0mm. The study indicated that the different combinations of LAB strains can positively influence the flavor development of indigenous fermented foods. Several properties of LAB i.e. acid production, proteolysis, production of diacetyl and autolysis can be explored for their use as starters or adjuncts.
TABLE
OF CONTENTS
Title Page i
Certification ii
Dedication iii
Acknowledgement iv
Table of Contents v
List of Tables vii
Abstract viii
CHAPTER ONE
1.0 Introduction 1
1.1 Aim and Objectives 2
CHAPTER TWO
Literature
Review 3
2.1 Lactic Acid Bacteria (LAB) 3
2.2 Proteinases 4
2.3 Peptide Uptake Systems 6
2.4 Regulation of the Proteolytic Systems 7
2.5 Technological Aspects of Proteolysis in
Diary Products 9
2.6 Traditional Fermented Foods 10
2.6.1 Ogi 11
2.6.2 Tempe kedele 11
2.6.3 Natto, tu-si, tao-si, tnua-nao 12
2.6.4 Kenkey 12
CHAPTER THREE
3.0 Materials and Methods 13
3.1 Collection of Samples 13
3.2 Sterilization of Materials 13
3.3 Isolation of Lactic Acid Bacteria 13
3.4 Identification of Lactic Acid Bacteria 14
3.4.1 Gram Staining 14
3.4.2 Biochemical Test 14
3.4.2.1 Catalase Test 14
3.4.2.2 Citrate Test 15
3.4.2.3 Methyl Red (MR) 15
3.4.2.3
Voges Proskauer (VP) 15
3.4.2.3 Indole Test 15
3.4.2.4 Sugar Fermentation Test 15
3.5 pH Determination 16
3.6 Measurement of Growth 16
3.7 Determination of Lactic Acid 16
CHAPTER FOUR
4.0 Results 18
CHAPTER FIVE
5.0 Discussion, Conclusion and Recommendation 23
5.1 Conclusion 24
5.2 Recommendation 24
References 25
LIST
OF TABLES
|
S/N
|
TITLE
|
PAGE NO.
|
|
1
|
Total Lactic acid
Bacterial Count of indigenous fermented foods
|
18
|
|
2
|
Colonial Morphology and Biochemical characterization of
the Lactic acid Bacterial species
|
20
|
|
3
|
Lactic acid
Bacterial species isolated from the respective samples
|
21
|
|
4
|
Proteolytic Activities of the isolates Measures by
Diameter Zone of Clearing
|
22
|
CHAPTER
ONE
1.0 INTRODUCTION
Proteases
constitute one of the most important groups of enzymes both industrially
academically. Proteases are the enzymes that hydrolyse proteins by addition of
water across peptide bonds and catalyse peptide synthesis in organic solvents
with low water (Ishtiaq et al.,
2010). Proteases are essential constituents of all forms of on earth, including
bacteria, fungi, actinomycetes, plant and animals. Proteases are classified
according to their structure or the properties of the activity site such as
serine, metallo, carboxyl, acidic, neutral, and alkaline (Nihan and Elif,
2011). They are generally used in detergents (Ishtiaq et al., 2010) food industries meat processing, cheese making,
silver recovery from photographic film (Hamid mukhtar and Ikram, 2018)
production of digestive and certain medical treatments of inflammation and
virulent wounds.
Lactic
Acid Bacteria (LAB) are Gram positive, fastidious, acid tolerant, generally
non-sporulating, catalase negative, devoid of cytochrome, and non-respiring rod
or cocci that are associated by their common metabolic and physiological
characteristics that produce lactic acid as a major or sole product of
fermentative metabolism. Lactic acid bacteria (LAB) have been used for the
fermentation of food and feed products since ancient days and today their major
applications are still in the food and feed industry as starter cultures.
They also
have medical pharmaceutical applications (Beg et al., 2003). Lactic acid bacteria are widely distribution in the
nature. The genera, Lactobacillus, Streptococcous, Lactococcus, Leuconostol,
Bifidobacterium, Carnobacterium, Enterococcus and Sporolactobacillus are known
as lactic acid bacteria. They can be divided into species, subspecies, variants
and strains. Each geneus and species has different characteristics but they are
generally Gram positive, non-sporing, cocci or rod, non-motile bacteria that
produce lactic acid as a major end-product during fermentation of carbohydrates
(Myat, 2008). Lactic acid bacteria ferment various carbohydrate mainly lactate
and acetate into lactic acid and acetic acid. LAB that only produce lactic acid
an end product are called homofermentative, those that also produce acetic
acid, ethanol and carbondioxide are termed heterofermentative (Hnin et al., 2015).
1.1 AIM AND
OBJECTIVES
The aim of this study is to isolate,
screen and identify proteolytic lactic acid bacteria from indigenous fermented
foods. The objectives are:
1. To isolate
and identify lactic acid bacteria from fermented food product (yogurt and
fermented milk).
2. To
determine the percentage occurrence of the isolates.
3. To
determine the proteolytic activities of selected fermented food
Buyers has the right to create
dispute within seven (7) days of purchase for 100% refund request when
you experience issue with the file received.
Dispute can only be created when
you receive a corrupt file, a wrong file or irregularities in the table of
contents and content of the file you received.
ProjectShelve.com shall either
provide the appropriate file within 48hrs or
send refund excluding your bank transaction charges. Term and
Conditions are applied.
Buyers are expected to confirm
that the material you are paying for is available on our website
ProjectShelve.com and you have selected the right material, you have also gone
through the preliminary pages and it interests you before payment. DO NOT MAKE
BANK PAYMENT IF YOUR TOPIC IS NOT ON THE WEBSITE.
In case of payment for a
material not available on ProjectShelve.com, the management of
ProjectShelve.com has the right to keep your money until you send a topic that
is available on our website within 48 hours.
You cannot change topic after
receiving material of the topic you ordered and paid for.
Login To Comment