1.1 Introduction
Cheese, a nutritious food consisting primarily of the curd, the semisolid substance formed when milk curdles, or coagulates. Curdling occurs naturally if milk is not used promptly: it sours, forming an acid curd, which releases whey, a watery fluid containing the soluble constituents; and it leaves semisolid curd, or fresh cheese. In some areas, cheese is still made simply by allowing milk to curdle naturally, or by mixing milk with juices or extracts that reduce it to curds and whey. Cheese making probably originated soon after humans first took milk from wild or domesticated animals (Britannica, 2011). Cheese is usually stored in its whey and consumed fresh, but this can only last for 3-5 days after which spoilage occurs. It is sometimes fried and used as a meat-substitute in stews and soups, or smoke-dried to enhance its keeping qualities (Belewu et al., 2005).
As a prelude to other parts of this study, this chapter will discuss the background upon which this study was initiated, the statement of problems that led to this study, the Aim and Objectives of the study. Others are Significance of the study, Scope of work, Research hypothesis and questions, Limitations of the Study and Definition of technical terms.
1.2 Background of Study
Cheese is one of the numerous products from the processing of milk (Scott, 1986). It is produced in a wide range of flavors, textures, and forms by coagulation of the milk protein casein (Omotosho, O.E., Oboh, G. and Iweala, E.E.J., 2011). It comprises of proteins and fat from milk, usually the milk of cows, buffalo, goats, or sheep. Approximately, one third of the world’s milk production is used for cheese manufacturing to conserve the most desirable milk components such as casein, fat, calcium and phosphorus (Kashtanova, 2010).
Cheese remains practically the only dairy product made from raw milk. Raw-milk cheeses are of a prime importance for local economies and consumers appreciate their large diversities in characteristics and taste. Indigenous microflora of raw milk leads to significant differences in the proteolysis and fermentation products and is mainly responsible for the typical sensory characteristics of raw-milk cheeses (Ylva, A and Anna, P, 1999).
Fresh milk is considered as a perfect food owing to its nutrition, diversity of flavors and texture, and good taste (Fox and Kelly, 2006). Hundreds of types of cheese from various countries are produced. Their styles, textures and flavors depend on the origin of the milk (including the animal's diet), whether they have been pasteurized, the butterfat content, the bacteria and mold, the processing, and aging. Herbs, spices, or wood smoke may be used as flavoring agents. The yellow to red color of many cheeses, such as Red Leicester, is produced by adding annatto. Other ingredients may be added to some cheeses, such as black pepper, garlic, chives or cranberries. Cheese making may have originated from nomadic herdsmen who stored milk in vessels made from the sheep's and goats' stomachs. Because their stomach linings contain a mix of lactic acid, wild bacteria as milk contaminants and rennet, the milk would ferment and coagulate (O’Connor, 1993).
West African soft cheese (Wara) is an excellent source of protein, fats and minerals such as calcium, iron and phosphorus, vitamins and essential amino acids, thus making it an important food in the diet of both old and young. Wara is made from milk which contains various micro-flora and lactobacillus species which makes it susceptible to spoilage within a short period of time. Traditionally, it is preserved in its whey which last barely a day or two. Wara is traditionally produced using latex extracts of the leaves of Calotropis procera (Omotosho et al., 2011).
Cheese making in Africa is not properly documented and it is largely dictated by tradition. However, production of cheese in African countries has increased and about one-third of the volume of milk is used for cheese (Food and Agricultural Organization, 2002). The clotting property of milk is important in both the quality and yield of cheese.There is a widespread of Wara in Nigeria. Wara is eaten in various forms such as raw cheese, flavored snack, sandwich filling or fried cake. Wara is usually manufactures from coagulants obtained from the juice Calotropis procera (Sodom Apple leaves) (Omotosho et al., 2011).
Cheese contains a host of nutrients like calcium, protein, phosphorus, zinc, vitamin A and vitamin B12. Calcium is one of the nutrients most likely to be lacking in the human diet. According to government statistics, nine out of 10 women and six out of 10 men fall short of calcium recommendations. The high-quality protein in cheese provides the body with essential building blocks for strong muscles. Calcium, the most abundant mineral in the body, is found in some foods, added to others, available as a dietary supplement, and present in some medicines (such as antacids). Calcium is required for vascular contraction and vasodilation, muscle function, nerve transmission, intracellular signaling and hormonal secretion, though less than 1% of total body calcium is needed to support these critical metabolic functions(Food and Nutrition Board, Institute of Medicine, 2010).
Calcium is a mineral that is an essential part of bones and teeth. The heart, nerves, and blood-clotting systems also need calcium to work. Calcium is used for treatment and prevention of low calcium levels and resulting bone conditions including osteoporosis (weak bones due to low bone density) (Watts, 2010), rickets (a condition in children involving softening of the bones), and Osteomalacia (a softening of bones involving pain). Calcium is also used for premenstrual syndrome (PMS), leg cramps in pregnancy, high blood pressure in pregnancy (pre-eclampsia), and reducing the risk of colon and rectal cancers.Some people use calcium for complications after intestinal bypass surgery, high blood pressure, high cholesterol, Lyme disease, to reduce high fluoride levels in children, and to reduce high lead levels (Sunderrajan S and Bauer JH, 1987)
Calcium carbonate is used as an antacid for “heartburn”. Calcium carbonate and calcium acetate are also used for reducing phosphate levels in people with kidney disease. It is not farfetched to study the nutritional composition of cheese (Wara) due to its abundance usage in and nutritional values, specifically, the calcium content. This will help in determining the appropriate composition and preparation of local cheese. It will also aid medical experts in prescribing local cheese as calcium supplements in rural communities and help in determining the recommended daily intake of cheese for appropriate calcium content (Dibba et al., 2000).
Therefore, in Nigeria where the research was carried out, the activities that was conducted is to evaluate the Calcium in Cheese for Recommended Dietary Allowance.
1.3 Statement of Problems
Investigation revealed that cheese (Ware), a locally made cheese contains nutrients of various types such as zinc, magnesium, calcium, Iron etc. Wara is a major food that provides calcium in humongous value. It’s of paramount importance to determine calcium content in Wara in order to monitor the recommended daily intake for infants and adults.
1.4 Aim and Objectives of Study
The aim of the study is to evaluate the Calcium in Cheese for Recommended Dietary Allowance. In achieving this aim, the following specific objectives were laid out as follows:
- The proportion of calcium content in local cheese (Wara); and
- The recommended daily intake of calcium in cheese.
1.5 Significance of Study
At the end of the study, the research will:
- Help medical experts in prescribing cheese as a local substitute to modern calcium supplement in rural areas.
- Help dietitians in diets to treat or help to manage condition like Osteomalacia.
This study will be of immense benefit to other researchers who intend to know more on this study and can also be used by non-researchers to build more on their research work. This study contributes to knowledge and could serve as a guide for other study.
1.6 Scope of Study
The scope of the research is focused on the Evaluation of Calcium in Cheese for Recommended Dietary Allowance. This study will cover the determination of calcium content in cheese using two different methods:
- Titrimetry;
- Atomic absorption spectroscopy (AAS)
1.7 Limitations of the Study
During the course of this study, many things militated against its completion, some of which are:
- Time Constraint: The time frame given to accomplish this project was very short due to school academic calendar and it was carried out under pressure which made the researcher not to implement some necessary features.
- Research material: availability of research material is a major setback to the scope of the study.
- Frequent power failure: This made the researcher append more money on fuel to ensure sustainable power.
- Financial Constraint: Insufficient fund tends to impede the efficiency of the researcher in sourcing for the relevant materials, literature or information and in the process of data collection (internet).
