PROPERTIES OF STORED TOMATO (Lycopersicum esculentum) CONCENTRATES

ABSTRACT

In  ensuring  the  prevention  of  losses  when  raw  agricultural  product  is  in  the peak  of  its  season  and to  assure  safety,  effective  method  of  packaging  and  processing  is  highly  indispensable.  This  study researched into the property  of stored tomato concentrate packed in  glass bottle, plastic  bottle and polyethylene  stored  in  the  presence  of  light  and  in  the  absence  of  sunlight.  Tomato  concentrate was  produced  by  concentrating  tomato  pulp  using  filtration  and  evaporation  to  ensure  minimum heat treatment.   Physico-chemical  analyses  were  carried  out  to  determine  the  total  titratable  acidity,  pH,  total  solids, total  carotene  content  and  lycopene  content.  Microbial  analyses  were  also  carried  out.  The  result showed  that  all  samples  showed  a  significant  increase  in  pH  with  decrease  in  total  titratable  acidity while  the  study  was  on  going.  The  range  of  pH  change  during  the  storage  was  from  3.86  in  the control  sample  to  4.41  in  the  sample  stored  at  atmospheric  condition.  At  room  storage  condition, the trend of  change  in total carotene  was from 3.78mg/100g  in sample  stored in glass bottle under room  condition  to  1.91mg/100g  in  the  sample  stored  in  polyethylene  pack  at  atmospheric condition.    For  lycopene,  the  range  of  value  recorded  throughout  the  period  of  storage  in  all  the sample  was  from  3.17mg/100g  in  glass  bottle  stored  under  room  condition,  to  1.49mg/100g  in  the sample  stored  in  plastic  package  at  atmospheric  condition.  Total  carotene  content,  lycopene content  of  all  the  samples  decreased  with  increase  in  the  time  of  storage,  the  brix  value  however remained  fairly  constant  throughout  the  period  of  storage.  The  highest  moisture  content  was recorded  in  the  sample  stored  under  room  condition  (92.56%)  during  week  ten  while  the  lowest was  recorded  in  the  sample  stored  in  polyethylene  under atmospheric  condition  during  the  twelfth week.  There  was  also  a  slight  reduction  in  the  colour  property  of  the  samples  stored  in  the  dark while  change  in  the  ∆E  value  was  pronounced  in  those  samples  stored  in  the  presence  of  light. Highest  number  colony  forming  unit  was  recorded  in  the  samples  stored  in  polyethylene  (16*10^3 CFU)  while the  lowest (10*10^3CFU)  was  recorded in the  samples stored in the glass bottles Also,  greatest  loss  of  lycopene  and  carotene  was  recorded  in  those  samples  stored  in  the  presence of  light.  While  those  packed  in  the  glass  retained  highest  concentration  of  lycopene  and  total carotene,  those  samples  stored  in  the  presence  of  light  inside  plastic  package  retained  lycopene  the least  at  the  end  of  twelve  weeks.  Generally,  samples  stored  in  the  dark  under  room  condition retained  their  nutrients  more  than  those  stored  under  atmospheric  condition  and  can  be  stored  up to  twelve  weeks  while  those  in  the  presence  of  light  would  have  loss  most  of  their  colour  property before  week  ten.  Tomato  concentrate  therefore  can  be  stored  effectively  even  using  polyethylene package  in  the absence  of direct light.   

Keywords:  Tomato,  Storage,  Properties,  Atmosphere,  Room,  Range,  significance,  physicochemical. 

 TABLE OF CONTENT 

Title Page                        

 Certification………..…………………………………………………………………………ii

 Dedication……………………………………………………………………………………iii 

Acknowledgement……………………………………………………………………………iv 

Abstract….……………………………………………………………………………………v 

Table of Content…………………………………………………………………………vi - viii 

List of Figures………………………………………………………………………………ix 

List of Tables…………………………………………………………………………………x 

CHAPTER ONE                          1 – 5 

1.0: Introduction…………………………………………………………………...1 

1.1: Cultivation of tomato fruits …………………………………………………..1 – 2

 1.2: Tomato and tomato products………………………………………………….2 – 3 

1.3: Problem statement……………………………………………………………....4 

1.4: Objective of the project…………………………………………………………4 – 5  

vii  1.5: Justification of Research objective……………………………………………...5 

CHAPTER TWO                  6 – 30

 2.0: Background……………………………………………………………………...6 

2.1.0: Tomato Quality Deterioration…………………………………………………7 – 8  

2.1.1: Physiological response…………………………………………………..…….8

 2.1.2: Respiration…………………………………………………………………….8 – 9 

 2.1.3: Transpiration…………….....................……………………………………….9 - 10

 2.1.4: Ethylene……………………………………………………………………….10 – 11 

 2.1.5: Physiological disorder……………………………………………….………..11 – 12 

 2.1.6: Mechanical damage…………………...………………………….………….12 – 13 

 2.1.7: Microbiological disorder……………………………………………………13 – 14  

2.2: Concentration as applied to tomato processing……………………………..14 – 16 

 2.3.0: Processing of tomato fruits………………………………………………….16 – 18  

2.3.1: Unit operation in tomato concentrates preparation…………………………..19 

2.3.2: Harvesting and Storage process………………………………………………20

 2.3.3: Washing and cleaning process……………………………………………......20

 2.3.4: Sorting and grading…………………………………………………………...21 

2.3.5: Pulping and Break process……………………………………………………22 – 23  

viii  2.3.6: Primary finishing process……………………………………………………..23 – 24  

2.3.7: Secondary finishing process…………………………………………………..24

 2.4.0: Evaporation as applied in tomato processing………………………………….24 – 25 

 2.4.1: Tomato juice evaporation………………………………………………………25 

2.4.2: Quality parameters influenced by thermal processing………………………….25 

2.4.2.1: Colour…………………………………………………………………………26 

2.4.2.2: Consistency……………………………………………………………………27 

2.4.2.3: Flavour………………………………………………………………………...27 – 28  

2.5.0: Nutritional value of tomato and tomato products……………………………….28 - 30 

CHAPTER THREE                           31 - 38 

3.0: Materials and methodology………………………………………...………….31

 3.1: Preparation of the sample…………………………………………….………..31

 3.1.1: Processing of the fruit…………………………………………….………….31 

3.1.2: Preparation of the pulp…………………………………………….…………31 

3.1.3: Preparation of packaging materials…………………………………………..31 – 32 

 3.1.4: concentration…………………………………………………………………32 - 33 

3.2.0: Storage………..............................................…………………………………34 

3.2.1: Determination of properties of stored tomato concentrates…………………..34 

ix  3.2.1.1: Determination of total titratable acidity……………………………………..34 – 35 

 3.2.1.2: Determination of total soluble solids………………………………………35 

3.2.1.3: Determination of Sugar acid ratio………………………………………….35

 3.2.1.4: Determination of pH………………………………………………………..36

 3.2.1.5: Determination of lycopene………………………………………………….36 

3.2.1.6: Determination of total carotene……………………………………………...36 – 37 

 3.2.1.7: Determination of colour property…………………………………………….37

 3.2.1.8: Determination of number of colony forming units…………………………...38

 3.3.0: Statistical Analysis……………………………………………………………...38 

CHAPTER FOUR                     39 – 51 

4.0: Result and Discussion……………………………………………………………39 

4.1: Effect of storage condition and packaging materials on Total Soluble solids……39 – 40  4.2: Effect of storage condition and packaging materials on total titratable acidity…...41 

4.3: Effect of storage condition and packaging materials on pH……………………….42 

4.4: Effect of storage condition and packaging materials on lycopene…………………43 – 44  

4.5: Effect of storage condition and packaging materials on total carotene…………….45 – 46 

4.6: Effect of storage condition and packaging materials on moisture content…………47 – 48  

4.7: Effect of storage condition and packaging materials on sugar-acid ratio…………..49 

x  4.8: Effect of storage condition and packaging materials on colour…………………….50

 4.9: Effect of packaging materials on the total number of colony forming units………..51 

CHAPTER FIVE                                 52

 5.0: Conclusion and Recommendation………………………………………………...52

5.1: Conclusion………………………………………….....…………………………..52

5.2: Recommendation………………………………………………………………….52 

References…………………………………………..…………………………………53 - 58