*Potential of Indigenous Vegetable-Fortified Food Products for Improved Human Nutrition… DOI: http://dx.doi.org/10.5772/intechopen.105996*

and because it requires no further preparation before consumption. Being a wheat flour product, it contributes greatly to the dietary energy of the population of most West African countries due to its high carbohydrate content [30–32]. Nevertheless, this baked food product is not exceptionally rich in the nutrients that are required for maintaining proper growth and good health, a phenomenon that is attributable to the perceived loss of nutrients during the processing of wheat seeds into flour [33].

As a result of this, research was embarked upon to improve the nutritional base of bread through fortification or enrichment using vegetable-based products [34–37]. Judging from the reported increase in malnutrition and other cardiovascular diseases in less privileged countries of the world, with an ever-increasing interest in the consumption of bread, as a convenience food, there is no other time to improve the nutrient of bread, than now [15]. Improving the nutrient base of bread involves improvement in the protein content and mineral content. It also involves enhancing the radical scavenging ability of the bread, thereby reducing the incidence of the occurrence of some of these degenerative diseases. Therefore, for any material to act as fortificant in bread it must be a good deposit of these nutrients [35, 38, 39]. However, some sensorial properties, such as color, texture, and taste of the fortified bread, were affected by fortification, depending on the plant materials used [40–43]. One of the major challenges being faced in the quest by researchers to fortify bread with these plant materials is the level of inclusion. There is a threshold at which these plant materials can be added to wheat flour during bread making that would preserve both the physical, sensory, and baking quality of the products [44]. Some successes have been recorded with regard to the level at which these materials are included in bread, but this varies with the type of plant materials.

Indigenous leafy vegetables have been shown to possess highly valuable nutritional benefits as a result of the contents of fiber, vitamins, minerals, proteins, and some phytochemicals. These vegetables have been shown to be readily affordable and ready sources of food and nutrients for indigent families in many African countries for a number of years. African population for centuries have been consuming traditional leafy vegetables in large quantities in the preparation of soups and culinary [45, 46]. Based on the information gathered from the literature, there is a dearth of information on the use African leafy vegetables for bread fortification. However, recent MicroVeg works have reported optimization of bread fortification with indigenous African leafy vegetable polyphenolic extracts in addition to the chemical composition and quality characteristics of wheat bread supplemented with *T. occidentalis*, *A. viridis*, and *S. macrocarpon* [15, 27, 29].

The MicroVeg process for the production of vegetable leaf-fortified bread is simple and easily adoptable for homemade bread and industrial purposes. The leafy vegetable to be used for the bread fortification was processed as illustrated in **Figure 2**. The leafy vegetables could be used in two forms: dried powder or as an aqueous slurry, both of which are polyphenol-rich. For the vegetable powder fortified bread, a premix of the wheat flour-vegetable powder was first made. The advantage of this premixing stage is to ensure even distribution of the vegetable powder in the wheat flour. This was done by replacing a known proportion of the wheat flour according to the proportions shown in **Table 1**. After the premixing stage, the required amounts of other standard baking ingredients were added step-wise. All other dry ingredients, such as sugar, salt, and yeast, were added to the mixture. The fat and required quantity of water were added and mixed. Water is a very crucial ingredient in bread baking as it determines the overall quality of the baked product. However, the quantity of water and other

## **Figure 2.**

*Process scheme for the production of leafy vegetable dried powder or wet slurry.*

standard ingredients needed during bread baking varies, due to differences in the water absorption capacities of different wheat flours. But for vegetable-fortified bread, the standard recipe in **Tables 1** and **2** resulted in good quality vegetable leaf-fortified bread.

For bread fortified with the vegetable leaf slurry, the process differs slightly from that of the dried leaf powder described above. Based on the different levels of vegetable inclusion in the wheat flour (**Table 2**) the water content of the leaf slurry and the balance of water required for blending were taken into consideration. After sorting


### **Table 1.**

*Formulation of wheat-vegetable powder composite flour for bread fortification.*

*Potential of Indigenous Vegetable-Fortified Food Products for Improved Human Nutrition… DOI: http://dx.doi.org/10.5772/intechopen.105996*


## **Table 2.**

*Formulation of wheat-vegetable slurry composite flour for bread fortification.*

the vegetable leaves, a slurry was prepared with the understanding that the moisture content of fresh leaves is 86% (dry matter = 14%). Blending about 100 g of fresh leafy vegetable requires 100 ml of water to obtain a smooth vegetable slurry (200 ml). Of the 200 ml slurry, 186 ml is water, and the solid content is 14 g. With this knowledge, the 1%, 3%, and 5% vegetable leaf slurry to be added during the preparation of bread translated to 14.3 g, 42.9 g, and 71.4 g, respectively. On the basis of 86% (average moisture content of vegetables), 12.3, 36.9 and 61.4 ml water will be present in 14.3 g (1%), 42.9 g (3%), and 71.4 g (5%) vegetable slurries, respectively. Since water is required during the mixing stage to form an acceptable dough, the quantity of water in the slurry was deducted from the water required. This is necessary in order to establish a basis for comparing the nutritional values of dried vegetable leaf-fortified bread with slurry-fortified bread. In vegetable bread production, the optimum mixing time and proofing time proposed by Famuwagun et al. [29] resulted in good quality vegetable-fortified bread. The products were then baked according to the conditions highlighted in **Figure 3** and allowed to cool to room temperature before packaging to ensure good quality vegetable-fortified bread as shown in figure.
