Memoire Online - Development of organic soup from dried vegetables grown in Rwanda

Fruits and vegetables are one among the most recommended and essential foods because of their nutritional quality and effects on human body. Some of the vegetables are considered to be important means of preventing cancer through diet, and researches have shown mounting evidence that people who avoid fruit and vegetables completely, or consume very little, are indeed at increased risk of cancers diseases (TERRY et al 2001).

Some of the vegetables such as salad can be eaten uncooked, while others require to be cooked or process before consumption. However, all the production got can not be consumed efficiently, and this can lead to the loss of a great part of the production of vegetables. It was observed that, there are many varieties of vegetables and that until now, locally, there was no way of processing them to increase their shelf life and to add to them value. For this reason and others, it was necessary to carry out a research on the way of processing vegetables in Rwanda.

Rwanda, as one of the tropical region countries experiences good climatic conditions and has a high production of different crops, among which fruits and vegetables occupy a non negligible place.

However, an important part of this production of fruits and vegetables is lost annually, because of poor post harvest handling. In fact, vegetables as well as fruits have high moisture content and high water activity (a_w). These lead them to be highly perishable since moisture content and water activity (a_w) are ones of the important factors to the growth of different microorganisms.

In addition, it is well known that during the harvest period, the price of many food commodities including vegetables, is too low so that farmers are losing and just after certain months, when comes the post harvest period, there is lack or shortage of foods, then the price becomes too high.

All these problems of production losses and fluctuation of the vegetable prices on the market, can be overcome if the production of vegetables were processed during the harvest period to increase their storage stability, so that they can be stored longer and be used or sold during the post harvest period. Keeping in mind that, water is the most important factor of the high perishability of vegetables, their simplest method of processing, is drying them in order to decrease their moisture content up to a level = 5% and water activity = 0.20, where microorganisms are not favored to grow.

When are dried, vegetables can be used in many other ways, it was necessary to study on how to develop a flavored organic soup ( for export ) from vegetables grown in Rwanda.

So these are the reason why the following research topic was chosen: DEVELOPMENT OF ORGANIC SOUP FROM DRIED VEGETABLES GROWN IN RWANDA.

If well used, this research will be very important and significant, since there will no longer be losses of vegetables because of lack of (or poor) handling. In fact, this research shows how the excess production of vegetables that can not be consumed directly during the harvest period, can be processed in order to increase its stability and its shelf life, so that it can be stored longer and be used further after.

Once again, the flavored organic soup produced, can be exported to other countries, enabling the country to diversify the products it exports and earn mach more foreign currency, what help in rising its economy.

The main objective of this study was to develop a flavored organic soup (quality export), from dried vegetables grown in Rwanda.

a. To formulate a flavoured soup (quality export), from dried vegetables, grown in Rwanda.

c. To determine the nutritional composition ( moisture content, carbohydrates, proteins, fats, minerals and Vitamin C content) of the formulated food.

b. Food processing under guidance of consumer needs, allows to achieve his satisfaction.

c. As moisture content in dried foods is too low, the storage stability and the quality of the food will increase. However, vitamin C content may be decreased by the fact of drying.

d. Dried soup has to be packed in containers that do not allow (moisture) rehydration.

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. It is sometimes confused with stew. The word soup originates from " sop", a dish originally consisting of a soup or thick stew which was soaked up with pieces of bread. The modern meaning of sop has been limited to just the bread intended to be dipped.

Commercial soup became popular with the invention of canning in the 19th century, and today a great variety of canned and dried soups are on the market. Dr. John T. Dorrance, a chemist with the Campbell Soup Company invented condensed soup in 1897. Today, Campbell's Tomato, Cream of Mushroom and Chicken Noodle soups are three of the most popular soups in America. Americans consume approximately 2.5 billion bowls of these three soups alone each

During the preparation of soups, there are so many important factors that have to be taken into consideration. Some of them are listed below :

The first one is «nitrate content». Since nitrates can be carcinogenic, generally, their use in food industry must as limited as possible. However their limitation becomes furthermore important in soup making. This is so because it has been demonstrated that , no nitrate was lost on cooking in accordance with the manufacturers' directions; even when simmered for up to 25 minutes (GARCIA-MATA et al 1995).

The second factor to be taken into account is the «microbiological quality» of the soup. In fact, studies have been carried out on the presence Clostridium perfringens, one of the pathogenic and heat resistant microorganism, in dehydrated soups and the organism was found in 18.2% of the samples. The soup mixes had the lower incidence compared to Spaghetti sauce mixes that had the highest incidence. One strain possessed heat-resistant spores that were able to withstand boiling at 97.4°C for one hour prior to isolation. The presence of preservatives in the food products did not influence the presence of C. perfringens in these food preparations. So it is very important to pay a strong attention on the microbiological quality of the soups and make sure that it will be safe for human consumption since the general presence of this microorganism in dehydrated soups and sauces may have epidemiological significance in Clostridium perfringens food poisoning, especially since these products are exposed to short besting periods (MITSURU, 1968).

The third factor, and last one on this list, is the «use of organic vegetables» if the soup must be commercialized. This will increase the consumers acceptability of the soup and help in marketing. Studies have demonstrated that if consumers were informed that soup is prepared with organic ingredients, they would improve their acceptability scores, whatever the soup type. They revealed that consumers appreciate soups made with organic crops and without seasoning

Drying is probably the oldest food preservation process practiced. Some foods, especially grains, are sufficiently dry as harvested or with a little drying remain unspoiled for long periods under proper storage conditions. However, most foods contain enough moisture to permit action by their own enzymes and by microorganisms, so that to preserve them by drying , the removal (or binding ) of moisture is necessary.

Drying is a mass transfer process resulting in the removal of water moisture by evaporation from a solid, semi-solid or liquid to end in a solid state. To achieve this, there must be a source of heat, and a sink for evacuation of the vapor thus produced. Notice that any method or technique that reduces the amount of available moisture, i.e., lowers the water activity (a_w), in a food, is also a form of drying (FRAZIER et al 1988).

Among different methods of drying, sun drying, solar drying, hot air drying, drum drying, freeze drying and microwave drying are briefly discussed here as they have been explained by Vieira (1996).

- Sun drying: or natural drying is used in hot climate, where moisture is removed by exposing foods to the sunrays without any artificially produced heat and without controlling temperatures, relative humidity, or air velocity.

- Solar drying: Uses solar energy to produce heat in an artificial equipment called solar dryer.

- Hot air drying: When mechanical dehydrators are used, the product to dry is placed on metal mesh belts in a tunnel or in a cabinet on trays where controlled, elevated temperatures are used. The air in dehydrators is heated ether by steam tubes or coils, or by being mixed directly with the combustion gasses of gas or oil. Electric resistance heaters can be used in some instances. The relative humidity and the air velocity must also be controlled.

- Drum drying: the products to be dried are allowed to flow onto the surface of two heated stainless steel drums located side by side and rotating in opposite directions with little clearance between them. The product dries on the drums and is scraped off by stationary blades fixed along the surface of the drum.

- Freeze drying: is increasingly applied to dry foods, beyond its already classical pharmaceutical or medical applications. It keeps biological properties of proteins, and retains vitamins and bioactive compounds. The freeze drying is carried out by first freezing the product and then subjecting it to a very high vacuum, wherein temperatures are high enough to assist in the evaporation of the moisture but low enough to prevent melting of the ice in the product. In this method, the water, existing as ice in the food, is evaporated directly as a vapor without passing through the liquid phase (sublimation). The vapor evaporated by sublimation is removed from the system by converting it into ice in a condenser, operating at very low temperatures, outside the freeze drying chamber.

- Microwave drying: microwaves are used in different drying applications including dehydration, concentration, and finish drying where traces of moisture remaining after conventional drying can quickly be removed from the inner portion of the product without overheating the already dried product.

In addition to these drying methods, there is also a new one, called supercritical drying or superheated steam drying, which involves steam drying of products containing water. Strange as it seems, this is possible because the water in the product is boiled off, and joined with the drying medium, increasing its flow. It is usually employed in closed circuit and allows a proportion of latent heat to be recovered by recompression, a feature which is not possible with conventional air drying, for instance. May have potential for foods if carried out at reduced pressure, to lower the boiling point ( www.wikipedia.org/wiki/drying ,29/5/2008).

The term "vegetable" generally refers to the edible part of a plant. The definition is traditional rather than scientific. It is somewhat arbitrary and subjective, as it is determined by individual cultural customs of cooking and food preparation.

Vegetables can be either whole plants or only some parts of plants served with the main course of a meal. Apart from their nutritive value, vegetables probably do more than any other group of foods to add appetizing colour, texture and flavour to our daily food. By a proper choice of vegetables, the desired flavour of meal can be obtained (SHAKUNTALA et al 2001).

According to SHAKUNTALA (2001); vegetables are classified on the basis of the parts consumed of the plants, such as roots, stems, flowers, etc. However this may not be satisfactory as some parts of the plants may be grouped under more than one heading. Hence, vegetables are subdivided into groups based on their cultural requirements. On this basis, the commonly used vegetables can be classified as follows:

a. Cole crops: Some examples of vegetables of this group are cabbage (Brassica oleracea L.var capitata), and cauliflower( Brassica oleracea L.var. botrytis).

b. Root vegetables: As examples of vegetables of this group, we can say ; carrot (Daucus carota), and beetroot (Beta vulgaris).

c. Cucurbits : As examples of vegetables of this group, we can say; cucumber (Cucumis sativus), and pumpkin (Cucurbita moschata).

d. Fruit vegetables : These are other vegetables, apart from cucurbits, for which the edible part is the fruit. As examples of vegetables of this group, we can say ; tomatoes (Lycopersicon esculentum), pepper (Capsicum annuum), egg plant ( Solanum melongena), and chow-chow or chayote (Sechium edule).

e. Green leafy vegetables: The main edible parts of vegetables of this group are leaves. As examples of vegetables of this group, we can say; amaranth ( The genus of Amaranthus), celery ( Apium graveolens, L. var duluce), and spinach (spinacea oleracea).

f. Tuber vegetables: As examples of vegetables of this group, we can say ; Irish potato(Solanum tuberosum), sweet potato (Ipomoea batatus), and tapioca or cassava (Manihot esculenta).

g. Bulbs: In this group of vegetables, the edible part is the bulb. It contains vegetables such as onions (Allium cepa), garlic (Allium sativum), and leek ( Allium ampeloprasum var porrum ).

h. Perennial vegetables: This group contains a number of vegetables, botanically unrelated, which are similar in that they are perennials. Some of them are here mentioned as asparagus ( Asparagus officinalis), and rhubarb ( Rheum rhaponticum).

i. Other vegetables: vegetables in this group can be broadly classified under the following heads: leguminous vegetables, drumstick ( Moringa oleifera), mashrooms (genus Agaricus ).

Vegetables are an important part of the human diet and a major source of biologically active substances such as vitamins, dietary fiber, antioxidants, and cholesterol-lowering compounds. Historically, the value of many plant nutrients and health-promoting compounds was discovered by trial and error. By the turn of the century, the application of chromatography, mass spectrometry, infrared spectrometry, and nuclear magnetic resonance allowed quantitative and qualitative measurements of a large number of plant metabolites. Approximately 50000 metabolites have been elucidated in plants, and it is predicted that the final number will exceed 200000. Most of them have unknown function. Metabolites such as carbohydrates, organic and amino acids, vitamins, hormones, flavonoids, phenolics, and glucosinolates are essential for plant growth, development, stress adaptation, and defense. Besides the importance for the plant itself, such metabolites determine the nutritional quality of food, color, taste, smell, antioxidative, anticarcinogenic, antihypertension, anti-inflammatory, antimicrobial, immunostimulating, and cholesterol-lowering properties. This review is focused on major plant metabolites that characterize the nutritional quality of vegetables. There are here divided in primary and secondary metabolites.

2.1.3.ii.a. PRIMARY METABOLITES Primary metabolites such as carbohydrates, amino acids, fatty acids, and organic acids are involved in growth and development, respiration and photosynthesis, and hormone and protein synthesis. Primary metabolites are found across all species within broad phylogenetic groups, and are produced using the same (or nearly the same) biochemical pathways.

?Carbohydrates Carbohydrates in vegetables occur as sugar monosaccharides , disaccharides , sugar alcohols , oligosaccharides , and polysaccharides (starch, pectins). In terms of their physiological or nutritional role, carbohydrates are often classified as available and unavailable. Available carbohydrates are those that are hydrolyzed by enzymes of the human gastrointestinal system to monosaccharides such as sucrose and digestible starch. Unavailable carbohydrates (sugar alcohols, many oligosaccharides, and nonstarch polysaccharides) are not hydrolyzed by endogenous human enzymes. The consumption of high dietary fiber foods has been found to reduce symptoms of chronic constipation, diverticular disease, and some types of colitis. It has been suggested that diets with low fiber may increase the risk of developing colon cancer, cardiovascular diseases, and obesity (HOUNSOME et al 2008 )

Proteins provide structural material for the human body and function as enzymes, hormones, and antibodies. Vegetables contain all essential amino acids, but some may be in lower proportions than are required for humans. Besides the importance for human metabolism, free amino acids contribute to the taste of vegetables (HOUNSOME et al 2008).

The vitamin B complex of vegetables includes the water-soluble vitamins thiamine (B1), riboflavin (B2), nicotinic acid (B3, niacin), pantothenic acid (B5), pyridoxine (B6), biotin (B7), and folic acid (B9). Vitamin B deficiency can cause polyneuritis (thiamine), cheilosis, angular stomatitis and dermatitis (riboflavin), pellagra, diarrhea, dermatitis and dementia (nicotinic acid), seborrhea, glossitis, peripheral neuropathies and microcytic anemia (pyridoxine), nausea, dermatitis (pantothenic acid, biotin), and anemia (folic acid). Green leafy vegetables such spinach, Brussels sprouts, cauliflower, turnip, and lettuce are good sources of B vitamins (HOUNSOME et al 2008).

Green vegetables such as Chinese cabbage, Brussels sprouts, watercress, and parsley are known to contain a relatively high proportion of polyunsaturated fatty acids, primarily in the form of alpha-linolenic acid. The consumption of monounsaturated fatty acids has been shown to reduce cholesterol levels and have a beneficial effect on some of the traditional risk factors for cardiovascular disease and type 2 diabetes (HOUNSOME et al 2008).

Plants contain citric, acetic, malic, oxalic, succinic, fumaric, quinic, tartaric, malonic, shikimic, aconitic, ascorbic acid ( Vitamin C ), and other organic acids. Green vegetables generally contain low concentrations of organic acids. Ascorbic acid, known as vitamin C, is an organic acid with strong antioxidant properties. Vegetables rich in ascorbic acid include spinach, spring onions, cress, cabbage, broccoli, cauliflower, sweet peppers, peas, and beans. Because vitamin C is a strong biological antioxidant, it is also linked to the prevention of degenerative diseases such as cataracts, certain cancers, and cardiovascular disorders (HOUNSOME et al 2008).

Plants produce a diverse assortment of organic compounds that do not participate directly in growth and development. These substances, traditionally called secondary metabolites, are often differentially distributed among taxonomic groups within the plant kingdom. Their functions, many of which remain unknown, and are being elucidated with increasing frequency. But generally secondary metabolites such as flavonoids, carotenoids, sterols, phenolic acids, alkaloids, and glucosinolates determine the color of vegetables, protect plants against herbivores and microorganisms, attract pollinators and seed-dispersing animals, and act as signal molecules under stress conditions. According to the nomenclature adopted by the British Nutrition Foundation, plant secondary metabolites can be divided into 4 major groups: phenolic and polyphenolic compounds (about 8000 compounds), terpenoids (about 25000 compounds), alkaloids (about 12000 compounds), and sulfur-containing compounds ( HOUNSOME et al 2008 ).

When drying foods, the key is to remove moisture as quickly as possible at a temperature that does not seriously affect the flavour, texture and colour of the food. If the temperature is too low in the beginning, micro organisms may survive and even grow before the food is adequately dried. If the temperature is too high and the humidity too low, the food may harden on the surface. This makes it more difficult for moisture to escape and the food does not dry properly.

Although drying is a relatively simple method of food preservation, the procedure is not exact. A «trial and error» approach often is needed to decide which techniques work best. Drying, like all methods of preservation, can result in loss of some nutrients.

· Calorie content: does not change, but it is concentrated into a smaller mass as moisture is removed.

· Thiamine, riboflavin, niacin: some loss during blanching but fairly good retention if the water used to rehydrate also is consumed.

· Minerals: some may be lost during rehydration if soaking water is not used. Iron is not destroyed by drying.

For best retention of nutrients in dried vegetables, they must be stored in a cool, dark, dry place and use within a year ( KENDALL et al 2006 ).

2. 2. SOME VEGETABLES ( INGREDIENTS ) USED

a. Description: Spinach (Spinacia oleracea) is a flowering plant in the family of Amaranthaceae. It is native to central and southwestern Asia. It is an annual plant (rarely biennial), which grows to a height of up to 30 cm. Spinach may survive over winter in temperate regions. The leaves are alternate, simple, ovate to triangular-based, very variable in size from about 2-30 cm long and 1-15 cm broad, with larger leaves at the base of the plant and small leaves higher on the flowering stem. The flowers are inconspicuous, yellow-green, 3-4 mm diameter, maturing into a small hard dry lumpy fruit cluster 5-10 mm across containing several seeds ( www.wikipedia.org/wiki/spinach, 29/5/2008).

Kingdom: Plantae Division: Magnoliophyta Class: Magnoliopsida Order: Caryophyllales Family: Amaranthaceae, Genus: Spinacia Species: S. oleracea

Carbohydrates	3.6 g
- Sugars 0.4 g
- Dietary fiber 2.2 g
Fat	0.4 g
Protein	2.9 g
Vitamin A equiv.469 ìg	52%
- â- carotene 5626 ìg	52%
Folate (Vit. B9) 194 ìg	49%
Vitamin C 28 mg	47%
Vitamin E 2 mg	13%
Vitamin K 483 ìg	460%
Calcium 99 mg	10%
Iron 2.7 mg	22%

2.2.2. POTATOES

a. Description: Potato is the term which applies either to the starchy, tuberous root vegetable crop from the various subspecies of the perennial plant Solanum tuberosum of the Solanaceae, or nightshade, family, or to the plant itself. There is general agreement among contemporary botanists that potato species originated in the Andes, all the way from Colombia and Venezuela to Chile and northern Argentina, but with a concentration of genetic diversity, both in the form of cultivated and wild species, in the area of modern day Peru. The evidence thus far shows that the potato was first cultivated in Peru some 7,000 years ago. The potato was introduced to Europe around 1700, and subsequently by European mariners to territories and ports throughout the world.The English word potato comes from Spanish patata (the name used in Spain). Another common name is "ground apple": pomme de terre in French. Potato plants grow high to the ground and bear yellow to silver flowers with yellow stamens. Potatoes are cross-pollinated mostly by bumblebees that carry pollen from other potato plants, but a substantial amount of self-fertilizing occurs as well. Any potato variety can also be propagated vegetatively by planting tubers, pieces of tubers, cut to include at least one or two eyes, or also by cuttings, a practice used in greenhouses for the production of healthy seed tubers ( www.wikipedia.org/wiki/potato ,29/5/2008).

a. Description: The leek , Allium ampeloprasum var. porrum (L.), also sometimes known as Allium porrum, is a vegetable which belongs, along with the onion and garlic, to the Alliaceae family. Two related vegetables, the elephant garlic and kurrat, are also variant subspecies of Allium ampeloprasum, although different in their uses as food. The edible part of the leek plant is sometimes called a stem, though technically it is a bundle of leaf sheaths. Rather than forming a tight bulb like the onion, the leek produces a long cylinder of bundled leaf sheaths which are generally blanched by pushing soil around them (trenching)( www.wikipedia.org/wiki/leek,29/5/2008).b. classification

a. Description : The tomato (Solanum lycopersicum) is a plant in the Solanaceae or nightshade family, as are its close cousins tobacco, chili peppers, potato, and eggplant. The tomato is native to Central, South, and southern North America from Mexico to Argentina. It is a perennial, often grown outdoors in temperate climates as an annual, typically reaching to 1-3 m (3 to 10 ft) in height, with a weak, woody stem that often vines over other plants. The leaves are 10-25 cm long, odd pinnate, with 5-9 leaflets on petioles, each leaflet up to 8 cm long, with a serrated margin; both the stem and leaves are densely glandular-hairy. The flowers are 1-2 cm across, yellow, with five pointed lobes on the corolla; they are borne in a cyme of 3-12 together. The word tomato derives from a word in the Nahuatl language, tomatl. The specific name, lycopersicum, means "wolf-peach" (compare the related species Et.alycocarpum, whose scientific name means "wolf-fruit", common name "wolf-apple") ( www.wikipedia.org/wiki/tomato ,29/5/2008).

a. Description : Apium graveolens is a plant species in the family Apiaceae, and yields two important vegetables known as celery and celeriac. Cultivars of the species have been used for centuries, whilst others have been domesticated only in the last 200-300 years. The petiole is main the part consumed. Apium graveolens is used around the world as a vegetable, either for the crisp petiole (leaf stalk) or fleshy taproot. In temperate countries, celery is also grown for its seeds, which yield a valuable volatile oil used in the perfume and pharmaceutical industries. Celery seeds can be used as flavouring or spice either as whole seeds or, ground and mixed with salt, as celery salt ( www.wikipedia.org/wiki/celery ,29/5/2008).

a. Description: The carrot (Daucus carota subsp. sativus) is a root vegetable, usually orange or white, or red-white blend in colour, with a crisp texture when fresh. The edible part of a carrot is a taproot. It is a domesticated form of the wild carrot Daucus carota, native to Europe and southwestern Asia. It has been bred for its greatly enlarged and more palatable, less woody-textured edible taproot, but is still the same species. It is a biennial plant which grows a rosette of leaves in the spring and summer, while building up the stout taproot, which stores large amounts of sugars for the plant to flower in the second year. The flowering stem grows to about 1 metre (3 ft) tall, with an umbel of white flowers. Carrots can be eaten in a variety of ways. They are often chopped and boiled, fried or steamed, and cooked in soups and stews, as well as baby and pet foods. Carrot juice is also widely marketed, especially as a health drink, either stand-alone or blended with fruits and other vegetables. The carrot gets its characteristic and bright orange colour from â-carotene, which is metabolised into vitamin A in humans when bile salts are present in the intestines. Massive overconsumption of carrots can cause hypercarotenemia, a condition in which the skin turns orange (although effects are less dangerous than those of vitamin A, which can cause liver damage). Carrots are also rich in dietary fibre, antioxidants, and minerals. Lack of Vitamin A can cause poor vision, including night vision, and vision can be restored by adding Vitamin A back into the diet ( www.wikipedia.org/wiki/carrot, 29/5/200).b. classification

a. Description : Onion is a term used by many plants in the genus Allium. They are known by the common name "onion" but, used without qualifiers, it usually refers to Allium cepa. Allium cepa is also known as the 'garden onion' or ' bulb' onion and ' shallot'. Allium cepa is known only in cultivation, but related wild species occur in Central Asia. The most closely-related species include Allium vavilovii and Allium asarense from Iran. However there are doubts whether the vavilovii collections tested represent genuine wild material or only feral derivatives of the crop ( www.wikipedia.org/wiki/onion ,29/5/2008).

Carbohydrates	9.34 g
- Sugars 4.24 g
- Dietary fiber 1.7 g
Fat	0.1 g
- saturated 0.042 g
- monounsaturated 0.013 g
- polyunsaturated 0.017 g
Protein	1.1 g
Vitamin A equiv. 0 ìg	0%
Thiamin (Vit. B1) 0.046 mg	4%
Riboflavin (Vit. B2) 0.027 mg	2%
Niacin (Vit. B3) 0.116 mg	1%
Vitamin B6 0.12 mg	9%
Folate (Vit. B9) 19 ìg	5%
Vitamin B12 0 ìg	0%
Vitamin C 7.4 mg	12%
Vitamin E 0.02 mg	0%
Vitamin K 0.4 ìg	0%

a. Description : Allium sativum L., commonly known as garlic, is a species in the onion family Alliaceae. Its close relatives include the onion, the shallot, and the leek. Garlic has been used throughout recorded history for both culinary and medicinal purposes. It has a characteristic pungent, spicy flavor that mellows and sweetens considerably with cooking. A bulb of garlic, the most commonly used part of the plant, is divided into numerous fleshy sections called cloves. The cloves are used as seed, for consumption (raw or cooked), and for medicinal purposes. The leaves, stems ( scape) and flowers (bulbils) on the head (spathe) are also edible and most often consumed while immature and still tender ( www.wikipedia.org/wiki/garlic , 29/5/2008 ).

Carbohydrates	33.06 g
- Sugars 1.00g
- Dietary fiber 2.1 g
Fat	0.5 g
Protein	6.36 g
- â- carotene 5 ìg	0%
Thiamin (Vit. B1) 0.2 mg	15%
Riboflavin (Vit. B2) 0.11 mg	7%
Niacin (Vit. B3) 0.7 mg	5%
Pantothenic acid (B5) 0.596 mg	12%
Vitamin B6 1.235 mg	95%
Folate (Vit. B9) 3 ìg	1%
Vitamin C 31.2 mg	52%
Calcium 181 mg	18%

Epidemiological, clinical, and laboratory studies have reported that garlic contains many biologically and pharmacologically active compounds. The majority of studies show that garlic lowers total serum cholesterol and LDL-cholesterol; inhibition of HMG-CoA reductase or squalene epoxidase appears to be the major mechanism. Lowering of blood pressure likely results from inhibition of angiotensin-converting enzyme activity. Antithrombosis effects may be related to inhibition of adenosine deaminase. Antioxidant effects may be related to the inhibition of lipoxygenase. The published studies in their aggregate suggest that appropriate usage of allium derivatives from garlic may potentially play a role in the maintenance of optimal cardiac function. However, further research is needed to examine the structure-function relationships of the various allium derivatives of garlic, the amounts in foods and supplements required for efficacy, and the possible effects of combining garlic with other nutrients and medications. The mechanisms of action of allium derivatives on various aspects of cardiac function require further clarification ( MICHELLE et al, 2000 ).

In conduction of this research, the work was partitioned and designed as follows:

- Drying of the vegetables: Vegetables were dried before being grinded and mixed. The drying

- Food formulation and development: This was achieved by proceeding as follows:

- Formulation of six different soups and carry out the first sensory analysis in order to choose one.

- Reformulation of the chosen soup according to the results of the first sensory analysis, setting a cooking method, and carry out a second sensory analysis.

- Consumer acceptability check : By the use of questionnaire, the researcher gave his product

- Laboratory analysis: This was done so as to know the chemical composition, and the nutritive

- Pricing mechanism : This was done for checking what would have to be price of the formulated food, so as to know whether the production of that product would be economically significant or not and if it would be affordable.

Except tomatoes and potatoes that were bought in Kabagali market, all other vegetables used as ingredients (carrots, celery, garlic, leek, onion, pepper, and spinach), were bought in Kimisagara market, trying to chose the best ones on sight and the most fresh, and then were transported at ambient temperature up to Kabagali where they were subjected to further treatments.

5 Kg of carrots, 1.5 Kg of celery, 1 Kg of garlic, 1 Kg of leek, 3 Kg of onion, 1 Kg of pepper, 3 Kg of potatoes, 3 Kg of spinach and 7.4 Kg of tomatoes were weighed with a balance. All these vegetables were then washed with plenty of water and carrots, onions, potatoes and tomatoes were peeled with a kitchen stainless steel knife prior to slicing. After that, all the vegetables were sliced into small size particles with means of a kitchen stainless steel knife or rape and then put into the hybrid dryer. The starting and the end time, as well as the temperature inside the dryer were both recorded.

In formulating the soup, six different types of soups, which were different in the composition of some ingredients such as potatoes, carrots and tomatoes, were proposed to people, and these ones were allowed to evaluate and criticize them.

	Composition per soup ( in % )
Ingredients	Soup A	Soup B	Soup C	Soup D	Soup E	Soup F
Potatoes	50	30	30	10	10	10
Carrot	10	30	10	30	50	10
Tomatoes	10	10	30	30	10	50
Spinach	5.5	5.5	5.5	5.5	5.5	5.5
Onion	8	8	8	8	8	8
Garlic	5.5	5.5	5.5	5.5	5.5	5.5
Leek	5.5	5.5	5.5	5.5	5.5	5.5
Celery	3	3	3	3	3	3
Pepper	2.5	2.5	2.5	2.5	2.5	2.5

Using a questionnaire ( see appendix 1 ), a sensory analysis was done in order to know and choose one most suitable soup. A selected panel of ten untrained panelists, was asked to take on each of the six soups and evaluate them by answering the questionnaire.

Data collected were assessed by analyzing the mean and the most accepted ( liked ) soup would have to be modified according to the consumer's suggestions, and taking into consideration the basic scientific principles.

Based on the results of the first sensory analysis, the researcher tried to modify the most accepted (liked) soup in order to meet the consumer preferences. This was done by taking into consideration the suggestions and recommendations given by the consumers on the first sensory analysis. For example the quantity of pepper was reduced from 2.5% up to 1%, and little cooking oil was included during cooking.

For establishing a good and correct cooking time, a second sensory analysis was carried out.

Three identical samples were prepared and cooked for different intervals of period and a six untrained panelists tested the three soups and answered a questionnaire ( see appendix 2 ).

For the first sample, 50g of food were taken, mixed with 800ml of water and 5ml of oil and then cooked for 15 minutes.

For the second sample, 50g of food were taken, mixed with 850ml of water and 5ml of oil and then cooked for 20 minutes.

For the third on, 50g of food were taken, mixed with 900ml of water and 5ml of oil

In order to know whether the researcher has met the consumer needs and preferences or not, and to be sure that the new product will be sold on the market, he carried out the consumer acceptability check.

This was achieved by using questionnaire ( see appendix 3 ), where fifteen untrained panelists were asked to assess all the characteristics of the product, as well as its packaging and its labeling, and rate them using a five-point hedonic scale that was provided. The product was firstly evaluated before being opened, then after opening and lastly after being consumed.

One Way ANOVA (Analysis Of the Variance) statistical method, and analysis of the mean, as well as computer software( MS EXCEL ) were used to analyze the data obtained from sensory evaluation.

The soup formulated was analyzed in the laboratory so as to know its chemical composition, and its nutritive value.

This was so important since, those information would have to be indicated on the label.

Thus, it was analyzed for the moisture content, ash and mineral content, carbohydrates, fat content, protein content and Vitamin C content.

The moisture content of the formulated food was checked in order to be able to estimate its storage stability and shelf life. It was also necessary to be checked so as to write its true value on the label.

For this a sample for moisture content determination was sent to the laboratory of ISAR - Rubona for being analyzed. The procedure used is as follows.

Different samples of the mixture (formulated food), were weighed and dried again in the microwave oven, being cooled and weighed at some intervals of time, until difference became less than 1.0 mg for 30minutes heating.

By calculation (W₁- W₂) the weight of moisture evaporated was determined.

As the formulated food had to be packed and well labeled, it has been necessary to determine its ash and mineral content so as to write the true value on the label.

For this a sample for ash and mineral content determination was sent to the laboratory of

- Incinerate the sample by heating it in a muffle furnace on a temperature of 500°C-600°C,

- Repeat the procedure until difference becomes less than 1.0 mg for 30 min heating

As the formulated food would have to be packed and well labeled, it was necessary to determine its carbohydrate content so as to write the true value on the label.

A sample for carbohydrate content determination was sent to the laboratory of ISAE - Busogo for being analyzed and analysis was done by Lane-Eynon method (see appendix 4)

Lipids are one of the major constituents of the foods, and an important source of energy. Nevertheless, over-consumption of certain lipid components such as cholesterol and saturated fats can be detrimental to our health. Because of that, the formulated food has been analyzed for the fat content and the true value is indicated on the label.

A sample for fat content determination was sent to the laboratory of ISAR - Rubona for being analyzed.

In order to determine the fat content of the food the soxhlet method ( see appendix 5) was used .

T he protein content of the food was determined in order to get true value that will be put on the label.

A sample for protein content determination was sent to the laboratory of ISAE - Busogo for being analyzed.

The protein content of the food was analyzed by the Kjeldahl method ( see appendix 6 ).

Vitamin C (in vegetables) is very heat sensitive. Hence, it is possible that during drying, the vitamin C content of different ingredients may decrease considerably.

Experiments for determining the vitamin C content of the formulated food, were carried out in KIST food processing laboratory, by using the method of Indophenol solution ( see appendix 7 ).

For calculating the average cost of production per unit, all the expenses made during the research ( cost of ingredients, transport, energy, and labor ) were calculated as well as the tools and machinery buying up. Then , the price of the formulated food were estimated by applying a reasonable benefit margin of 15%.

A flavoured organic soup was developed as explained in chapter three. This chapter four , focuses on the results obtained from different experiments, and from sensory evaluation as well as their discussion.

These results are presented and discussed in the same order as the steps of the research design.

The results obtained from the experiment of drying are summarized in the table below

Vegetable	Mass before preparation ( Kg )	Mass after preparation & before drying ( Kg )	Mass after drying ( Kg )	Water evaporated ( Kg )	Drying time ( hours )	Drying T° ( °C )
Carrot	5	3.80	0.36	3.44	9	60
Celery	1.5	1.00	0.08	0.92	4
Garlic	1	0.82	0.26	0.56	10
Leek	1	0.80	0.06	0.74	7
Onion	3	2.00	0.28	1.72	6
Pepper	1	0.96	0.17	0.79	6
Potatoes	3	1.88	0.50	1.38	6
Spinach	3	2.60	0.18	2.42	8
Tomatoes	7.4	6.00	0.48	5.52	12

As it can be observed in the table, the drying time was affected by the initial moisture content, and the structure of vegetables. That is why tomatoes ( with high moisture content) have a long drying time, followed by garlic which the structure does not allow easy removal of water.

From six different soups proposed, a questionnaire was used for sensory analysis in order to know and choose one most suitable soup.

The table below shows the mean score of the results obtained by each of sensory attributes assessed for the six soups (in percentage).

	Score obtained by different soup ( in % )
	Soup A	Soup B	Soup C	Soup D	Soup E	Soup F
Appearance	54	62	60	62	69	58
Aroma	55	53	53	55	65	56
Colour	62	60	58	55	66	59
Taste	55	56	58	56	62	57
Texture	56	57	53	53	60	60
Overall acceptability	49	58	54	57	67	53

As you can see in the table, the fifth soup (Soup E) was the most appreciated with respect to all characteristics, and had a record of 67% in overall acceptability.

However, at this step, there were also many other suggestions and recommendations; 69% of the panelists suggested to reduce the quantity of pepper, 18% wanted it to be removed, while 13% did not say anything about it. With that 72% of them said that the palatability could be increased by addition of little cooking oil, and 58% recommended the cooking time to be lengthened.

Based on the results of the first sensory analysis, the most appreciated food (soup E) was reformulated in order to meet the consumer preferences.

Ingredients	Quantity
Carrot	50%
Potatoes	10%
Tomatoes	10%
Onion	8%
Garlic	6%
Spinach	5%
Leek	5%
Celery	3%
Salt	2%
Pepper	1%

The flow chart of the flavoured dry vegetable soup development was established as follows:

After reformulation of the soup that was liked, the researcher carried out a second sensory analysis for establishing good and correct cooking method and time.

Three identical samples were prepared and cooked for different intervals of period as described in chapter three. The following are the mean score of the results obtained by each of the sensory attributes assessed for the three soups (in percentage).

	Score obtained by different soup ( in % )
	Soup1	Soup2	Soup3
Appearance	96	93	94
Aroma	75	82	80
Colour	92	90	92
Taste	95	95	89
Texture	87	85	87
Overall acceptability	94	90	91

- The first soup (cooked for 15 min) is the most appreciated, but 16% of the panelists said that they could still feel some little undercooked odour.

- The last two soups did not have the same undercooking sign odour, but also have lost some of the good flavour found in soup1

Development of organic soup from dried vegetables grown in Rwanda

Chapter One: INTRODUCTION

2. 2. SOME VEGETABLES ( INGREDIENTS ) USED

2.2.2. POTATOES