Development of organic soup from dried vegetables grown in Rwanda

ABSTRACT

A soup is a food that is made by combining ingredients such as meat or vegetables in stock or hot/boiling water, until the flavor is extracted, forming a broth, but here, only vegetables were used to develop an organic soup. Vegetables are defined as either whole plants or only some parts of plants served with the main course of a meal. The edible parts can be stems, roots, leaves, flowers, fruits and / or grains. They normally contain between 90 - 96 % of moisture when they are fresh. Drying was found to be one of the means of processing and preserving them.

Value was added to the dried vegetables, by mixing different ingredients in well defined proportions, and developing a well appreciated naturally flavoured vegetable soup.

Different vegetables used as ingredients ( carrots, celery, garlic, leek, onion, pepper, potatoes, and spinach ), were bought in Kimisagara market, then dried into a hybrid dryer, blended, weighed and mixed to develop the soup which was packaged in plastic bags and labeled. Laboratory analysis and sensory evaluation were carried out so as to know the chemical composition of the soup and its consumer acceptability. The soup was found to contain an average value of 4.98% moisture content, 95.02% total solid matter, as well as 13.06% crude protein, 3.17% lipids, 8.44% ash & minerals, 1.66% vitamin C, and 68.69% total soluble sugars.

The mean score of obtained on overall acceptability of the soup showed that it was accepted and judged to be satisfactory.

Keywords: Soup, Vegetable.

LIST OF ABBREVIATIONS

ANOVA : Analysis of the variance

a_w : Water activity

ISAE : Institut Supérieur d`Agriculture et d`Elevage

ISAR : Institut des Science Agronomiques du Rwanda

MC : Moisture content

LIST OF FIGURES AND TABLES

1. FIGURES Pages

Figure 2.2.1 : Picture of spinach................................................................12

Figure 2.2.2 : Picture of potatoes ..............................................................13

Figure 2.2.3 : Picture of leek....................................................................14

Figure 2.2.4 : Picture of pepper.................................................................15

Figure 2.2.5 : Picture of tomatoes.............................................................16

Figure 2.2.6 : Picture of celery..................................................................17

Figure 2.2.7 : Picture of carrot...................................................................18

Figure 2.2.8 : Picture of onion...................................................................19

Figure 2.2.9 : Picture of garlic...................................................................20

Figure 4.1: dried vegetables (after the process drying)......................................28

Figure 4.2.2 : flow chart of soup development................................................30

Figure 4.3.1 : graph of comparison between sensory attributes ( before opening ).......31

Figure 4.3.2 : graph of comparison between sensory attributes ( after opening )........33

Figure 4.3.3. : graph of comparison of acceptability before and after opening..........34

2. TABLES

Table 2.2.1: Nutritional value of spinach.......................................................12

Table 2.2.2: Nutritional value of potato .......................................................13

Table 2.2.5: Nutritional value of Tomato.......................................................16

Table 2.2.6: Nutritional value of celery.........................................................17

Table 2.2.7: Nutritional value of carrot..........................................................18

Table 2.2.8: Nutritional value of onion...........................................................19

Table 2.2.9: Nutritional value of garlic...........................................................20

Table 3.3.2: composition of six proposed soups................................................23

Table 4.1: results from the experiment of drying..............................................28

Table 4.2.1: results of the first sensory analysis................................................29

Table 4.2.2.a : composition of the formulated soup...........................................29

Table 4.2.2.b : results of the second sensory analysis.........................................30

Table 4.3.1.a : results of consumer acceptability check (before opening)..................31

Table 4.3.1.b : summary of results of ANOVA ( before opening )..........................32

Table 4.3.2.a : results of consumer acceptability check (after opening)....................32

Table 4.3.2.b : summary of results of ANOVA ( after opening )...........................33

Table 4.3.3. : comparison of acceptability before and after opening........................34

Table 4.3.4 : results of consumer acceptability check for packaging and labeling........35

TABLE OF CONTENT

Declaration............................................................................................i

Certificate.............................................................................................ii

Dedication.............................................................................................iii

Acknowledgments....................................................................................iv

Abstract................................................................................................v

List of abbreviations.................................................................................vi

List of figures and tables...........................................................................vii

Table of content.....................................................................................viii

Chapter One : INTRODUCTION..............................................................1

1.1. Problem statement..............................................................................1

1.2. Significance of the study......................................................................2

1.3. Objectives of the study.......................................................................2

1.3.1. Main ( overall) objective.....................................................................2

1.3. 2. Specific objectives...........................................................................2

1.4. Hypothesis........................................................................................3

Chapter Two: LITERATURE REVIEW.....................................................4

2.1. Definitions.......................................................................................4

2.1.1. Soup............................................................................................4

2.1.2. Drying ..........................................................................................5

2.1.3. Vegetables.....................................................................................6

2.1.3.i. Classification of vegetables................................................................7

2.1.3.ii. Nutritional composition of vegetables.................................................8

2.1.3.ii.a. Primary metabolites ......................................................................8

2.1.3.ii.b. Secondary metabolites.................................................................10

2.1.3.iii. Effect of drying on vegetables..........................................................10 2. 2. Some vegetables ( ingredients ) used ......................................................11 2.2.1. Spinach .......................................................................................11

2.2.2.Potatoes.........................................................................................12 2.2.3. Leek..........................................................................................13

2.2.4. Pepper ........................................................................................14

2.2.5. Tomatoes .....................................................................................15

2.2.6.Celery...........................................................................................16 2.2.7.Carrot...........................................................................................17 2.2.8.Onion...........................................................................................19 2.2.9. Garlic .........................................................................................20

Chapter Three : MATERIALS AND METHODS........................................22

3.1. Research design................................................................................22

3.2. Source of raw materials ....................................................................22

3.3. Experimental procedures.......................................................................22

3.3.1. Preparation and drying of the vegetables................................................22

3.3.2. Food formulation and development......................................................23

3.3.2.i. Food formulation proposal...............................................................23

3.3.2.ii. First sensory analysis.....................................................................23

3.3.2.iii. Reformulation and second sensory analysis..........................................24

3.3.3. Consumer acceptability check...........................................................24

3.3.3.i. Statistical methods used.................................................................24

3.3.4. Laboratory analysis.........................................................................25

3.3.4.i. Moisture content determination.......................................................25

3.3.4.ii. Ash and mineral content determination.............................................25

3.3.4.iii. Carbohydrates content determination................................................26

3.3.4.iv. Fat content determination.............................................................26

3.3.4.v. Protein content determination.........................................................26

3.3.4.vi. Vitamin C content determination...................................................27

3.4. Pricing mechanism........................................................................27

Chapter Four : RESULTS AND DISCUSSION..........................................28 4.1.Drying of the vegetables...................................................................28

4.2. Food formulation and development.....................................................29

4.2.1. First sensory analysis....................................................................29

4.2.2. Reformulation of the food and second sensory analysis..............................29

4.3. Consumer acceptability check............................................................31

4.3.1. Before opening.............................................................................31

4.3.2. After opening...............................................................................32

4.3.3. Comparison of acceptability before and after opening..............................34

4.3.4. Assessment of the packaging and the labeling..........................................35

4.4. Laboratory analysis.........................................................................35

4.5. Price of the product.........................................................................36

Chapter Five : CONCLUSIONS AND RECOMMENDATIONS

5.1. Conclusions................................................................................37

5.2. Recommendations ..........................................................................37

REFERENCES......................................................................................38

APPENDICES....................................................................................39

1. Questionnaire for suitable food formulation ..............................................40

2. Questionnaire for suitable cooking time and method ...................................42

3. Questionnaire for consumer acceptability check..........................................43

4. Determination of total reducing sugar by Lane-Eynon method.........................45

5. Determination of the fat content by the Soxhlet method..................................47

6. Determination of protein content by the Kjeldahl method.................................48

7. Determination of vitamin c content by indophenol solution...........................50

8. Tables of results for consumer acceptability check ( before opening)...................51

9. Tables of results for consumer acceptability check ( after opening).....................52

10. Pricing mechanism for the developed soup...............................................53

11. Label used.......................................................................................54