Food Science and Technology Project Topics

Nutritional Evaluation of Complementary Food From Sorghum, African Yam Bean, Carrot and Cray Fish

Nutritional Evaluation of Complementary Food From Sorghum, African Yam Bean, Carrot and Cray Fish

Nutritional Evaluation of Complementary Food From Sorghum, African Yam Bean, Carrot and Cray Fish

Chapter One

Aim and Objective of the Study

The aim of the study is evaluated the nutrient of food produced from blends of sorghum, African yam, carrot and crayfish.

Objective of the Study

The following are the aims and objectives of this project work, the objective of the study are:

  1. To produce flour from yam bean, sorghum, carrot and crayfish
  2. To prepare complementary foods from the flour produce from the above materials
  3. To determine the proximate composition, vitamin composition of the complementary food
  4. And to examine the organoleptic/sensory attributes of the complementary food




African yam bean (AYB) (Sphenostylis stenocarpa)

African yam bean is known and called different names by different tribes in Nigeria, some of the names are Azama, Ijiriji, Azam, and Uzaaki in Igbo; Girigiri in Hausa; Akpaka in Delta and Nsama in Ibibio. Other names are Okpodudu, Ahaja, Nzamiri, Odudu and Sese in Igala. In some parts of Ghana, it is called Kulege or Kutreku. African yam bean belong to the family: Fabaceae (alt. Leguminosae) subfamily: Faboideae tribe: Phaseoleae subtribe: Phaseolinae., also placed in: Papilionaceae. It is also called yam pea in English and it is usually cultivated in the following African regions Northeast Tropical Africa: Chad; Ethiopia East Tropical Africa: Kenya; Tanzania; Uganda, West-Central Tropical Africa: Burundi; Central Africa Republic; Zaire West Tropical Africa: Cote D’Ivoire; Ghana; Guinea; Mali; Niger; Nigeria; Togo South Tropical Africa: Angola; Malawi; Zambia; Zimbabwe (USDA, 2007).

African yam bean is grown both for its edible seeds and its tubers (Klu et al., 2001). The seeds are mostly used in some regions. It is a vigorous vine which twines and climbs to heights of about 3m and requires staking, with its prolific spattering of large flowers which may be pink, purple, or greenish with white, making it an attractive ornamental (NAS, 2009). The slightly woody pod which contains 20 to 30 seeds is up to 30cm long and mature within 170 days (Klu et al., 2001). The seeds of African yam bean vary in sizes and shapes. The seed coat has a range of colors from pale white to black with spotted or mottled grey, cream and brown in between. In Nigeria, it is grown mostly in the northern part where it is grown mainly for its seed (Alozie et al., 2009).

Distribution of African Yam Beans

Sphenostylis stenocarpa is native to tropical west and central Africa and is cultivated in southern and eastern Africa (Klu et al., 2001). Both wild and cultivated types now occur in tropical Africa as far south as Zimbabwe, throughout West Africa from Guinea to southern Nigeria. It thrives on deep, loose sandy and loamy soils with good organic content and good drainage. It grows better in regions where annual rainfalls range between 800-1400mm and where temperatures are between 19-27°C (Klu et al., 2001). The plant flowers after 90days and the pods mature in 140 to 210days. The tubers are ready to harvest 150 to 240days after sowing. Cultivation conditions for African Yam Beans.

 African yam bean processing methods used


Roasting is a traditional processing technique, it has the capacity to develop attractive flavours in foods so treated. It also induces important functional properties, attributes that should be compatible with nutritional value (Bressani, 2003).


Fermentation is one of the oldest and cheapest traditional processing methods used in the home and industries to improve the nutritional quality of food and reduces anti nutrient and toxic substances like phytic acid, polyphenols and oxalic acids, Hydrogen cyanide, raffinose and stachyose among others to improve food use (Mahungu et al., 2007). It is the metabolic process in which carbohydrates are oxidized with the release of energy. During fermentation, the microbial enzymes converts storage nutrient in foods to readily utilizable form (Rajalakshimi and Ramakrishanan, 2007). Fermentation begins when a food rich in simple sugars, yeast, and water are combined and left at room temperature. During the first stage, the yeast cells multiply, using the sugars for energy, and produce small amounts of alcohol (Byrd-Bredbenner et al., 2007). Many foods which are inedible are made edible in their unfermented form and this is brought about by the extensive hydrolysis of the indigestible components and the removal of anti-nutritional factors by the micro-organisms.

Reasons for Fermentation

Some reasons why fermentation of legumes is used in the preparation of foods are:

  • Legumes often contain substances that are undesirable, such as the trypsin, phytates among others. The treatments of the beans (soaking or heating) in preparation for fermentation or the enzymes produced by the microorganisms remove or destroy these factors.
  • Moist products spoil readily, however after fermentation some products will keep without refrigeration for extended periods of time. This is especially true of the fermented products that are high in salt.
  • All the legume fermentations involve the action of proteolytic and lipolytic enzymes with the result that the final products are more digestible.
  • Almost invariably the final product has a changed flavor more acceptable to the consumer.
  • In many instances the microorganisms increase nutrients such as vitamins, including riboflavin and vitamin B12 in some of the bacterial fermentations.
  • Finally, fermentation may reduce energy requirements. Thus, a short cooking may be the major energy input required while the microorganisms do the rest of the work by using energy from the substrate.

Source: Hesseltine and Wang (2000).

In addition, fermentation equally extends shelf life and level of safety (Hesseltine and Wang, 2000). It increases essential amino acids like methionine, improved palatability, increase non protein nitrogen (Reddy and Salunkhe, 2000). Proteolytic acid and amylolytic enzymes from micro-organism in fermentation process enhance digestibility and nutritional quality (Murato et al., 2007). It equally enhances flavour, aroma, texture, keeping quality and improves nutritive values (Eka, 2000). Fermented corn, cowpea and African yam bean are known to have higher nitrogen balance than its unfermented counterparts (Eka, 2000).

Processing of african yam bean and its effect

Most legumes are not fit for consumption in their raw state except they undergo some processing operations. Processing is done to improve the quality and functionality of foods, for increased bioavailability of nutrients and reduction of undesirable compounds such as toxins and non-nutritional compounds. African yam bean is one of such legumes that requires careful and appropriate processing for consumer palatability and safety. This is because pulses are generally high in compounds that alter normal metabolic processes. Over the years, the bean has been pre-processed and processed using different methods. Such methods includes: germination, roasting, fermentation, soaking as well as cooking or boiling.

Germination in food processing is a process where seeds are steeped or soaked for a period of time and then sprouted at the early stage of development of seeds to plant. Some authors have reported that germination results in improved flavour, nutritional composition, amino acid content and reduction of non-nutritional compounds in many legumes (Rumiyati et al., 2012). In addition to this, germination results in breakdown of complex carbohydrates in legumes into simple sugars through the action of endogenous enzymes thereby enhancing digestibility (Nkhata et al., 2018). It was reported that germination of AYB resulted in improved protein quality and enhanced the bioavailability and digestibility of other nutrients with a marked decrease in non-nutritional compounds like oxalate, phytic acid, trypsin inhibitors amongst others (Nwosu, 2013). Germination also improved the antioxidant content of AYB, for instance, it has been demonstrated from literature that the antioxidant content and free radical scavenging activity of the bean improved significantly after germination (Uchegbu, 2015). Hence, germinated AYB meal is said to be a good dietary inclusion for individuals with complications from oxidative stress, hyperlipidemia, and diabetes.

Roasting has also been used in the processing of AYB and was reported to have increased the minerals composition such as calcium, potassium, phosphorus, magnesium, etc of the bean as well as resulting in great decrease in non-nutritional compounds (Ndidi et al., 2014). Uchegbu (2015) stated that roasting improved the phosphorus content of the bean, while tannin content was non-detectable, although this was attributed to the removal of the seed coat that resulted from roasting. This method has been described as a viable method of preparing AYB snacks which are mostly consumed with palm kernel in the eastern part of Nigeria (Uchegbu, 2015).

Fermentation is used in the modification of the biochemical composition of foods through the action of enzymes and bacteria (Nkhata et al., 2018). This process improves the functional and organoleptic properties of many legumes as well as their bioavailability. It has been reported that fermentation led to a significant (P < 0.05) decrease in phytate composition and an increase in the phosphorus content caused by the breakdown of phytates by the activity of the enzyme phytase (Nkhata et al., 2018).

Soaking has been used in the pre-processing of AYB. It involves the hydration of legumes for a specified period before cooking or further processing to soften the seed thereby reducing the cooking time. For instance, Ene-Obong and Obizoba (1996) reported that soaking of AYB for 6–12 h before cooking reduced the cooking time of the bean by over 50%. In a similar study on Bambara groundnut, the hard-to-cook attribute of the seed was alleviated by soaking before cooking at elevated temperatures, which led to a significant decrease in cooking time (Ojo, 2018). Although this processing operation seems desirable, it may result in loss of important minerals. For instance, it has been reported that soaking for up to 24 h resulted in a significant decrease in calcium, magnesium, and iron content of AYB as these minerals leached into soaking water (Ene-Obong and Obizoba, 1996). A slight increase in protein up to 10% and a minute increase in phosphorus were observed by this author. In all, the processing of AYB is aimed at improving the nutritional, functional and organoleptic quality of the bean while decreasing the non-nutritional compounds present.





            African yam bean (Sphenostylis stenocarpa), sorghum (Sorghum bicolor), carrot (Daucus carota L.) and crayfish (Procambarus clarkia) were purchased in the main market of Owo in Ondo State. The complementary food was processed using the raw materials listed above in the processing laboratory of Food Science and Technology. After processing, the samples was then analyze for proximate, vitamin and mineral in the Chemistry Laboratory of Food Science and Technology, Rufus Giwa Polytechnic in Owo, Ondo State.


 Preparation of African yam bean flour

            The African yam bean flour was prepared according to the method (Eneche, 2006). During preparation, one kilogram of African yam bean seeds which were free from dirts and other foreign particles such as stones, leaves and sticks. It was then weighed, washed and soaked in 3 litres of potable water containing 0.1% sodium metabisulphite solution (Na2S2O5) at room temperature (30±2oC) for 12h. The soaked seeds were drained rinsed and dehulled manually by rubbing in between palms. The dehulled, seeds were boiled in an electrically heated pot at 100oC for 30min. The boiled seeds were drained, spread on the trays and dried in the cabinet dryer at 60oC for 8h. The dried seeds were milled using attrition mill and sieved through a 500 micron mesh sieve. The boiled African yam bean flour produced was packaged in an airtight plastic container for blending and preparation of complementary foods.




Table 4.1: Proximate composition (%) of complementary food samples





The study showed that the substitution of sorghum flour with African yam bean, carrot and crayfish flours in the formulation of complementary foods improved the nutrient contents of the products. The high protein, carbohydrate and vitamin contents of the samples coupled with their sensory properties revealed that the formulations will enhance the growth, development and well-being of infants and young children in addition to the affordability of the products. Generally, the supplementary foods with African yam bean, carrot and crayfish flours could be regarded as appropriate due to their nutrient compositions at affordable price as compared to infant food formula.


It is therefore recommended that the research on this study should be carried out by other researchers to obtain more attainable results and the complemented foods produced from sorghum, African yam bean, carrots and crayfish flours many be incorporated into infants foods due to its high nutritive values.


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