1.1 Introduction
Milk products are a type of food produced from or containing the milk of mammals, most commonly cattle, water buffaloes, goats, sheep, and camels. Dairy products include food items such as yogurt, cheese and butter. A facility that produces dairy products is known as a dairy or dairy factory. Milk is a highly nutritious food that serves as an excellent growth medium for a wide range of microorganism. Milk and its' derivatives are considered vehicle of Staphylococcus aureus for human infections and enteropathogenic Escherichia coli. The microbiological quality of milk and dairy products is influenced by the initial flora of raw milk, the processing conditions and post heat treatment contamination.
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, Limitations of the Study and Definition of technical terms.
1.2 Background of Study
Fermented milk products are cultured dairy products made from skim, whole or slightly concentrated milk, that require specific lactic acid bacteria to develop their characteristic flavor and texture. Fermented milks are usually fluid or semi-fluid in nature and all contain lactic acid in varying proportions. Fermentation of milk modifies its properties resulting in beverages such as yoghurt; kefir and other cultured dairy products (Webb et al., 1980).
Fermented milks in general have a good nutritional value that compares favorably with that of milk from which they are made (Abou Dawood et al., 1993).
Yoghurt and other cultured dairy products are highly nutritious foods which in some circumstances also have therapeutic value (Deeth, 1984). Yoghurt contains all the elements of nutrition found in milk in more digestible form (Abou Dawood et al., 1993). Yoghurt is always made from cow’s or baffaloe’s milk, although production from cow’s milk is economically less expensive than cows and baffaloe’s milk (Abbrahamsenet al., 1981).
In some countries, cow’s milk is consumed as fluid milk, even on a commercial basis and the components of cow’s milk are of considerable market interest (Haenlein, 1995).
Since the cow is the animal of poor people and its milk is consumed fresh, in addition to the possibility of manufacturing dairy products from this milk, especially being focused on the cow as a major dairy animal in the household.
Therefore, in Nigeria where the research was carried out, the activities that was conducted is to know the Production and Sensory Evaluation of the Blend of Cow Milk and Soya Milk to Yoghurt.
1.3 Statement of Problems
The direct fortification of dairy products with vegetable proteins has been increasing because of reasonably low prices of vegetable proteins compared to animal protein, low fat product and nutritional healthy value, regarding the lactose intolerant. The direct consumption of vegetable proteins in food products also has been increasing over the years because of animal diseases, global shortage of animal protein, strong demand for wholesome and religious food, and economic reasons (Asgar et al., 2010). The development of nutritionally balanced protein foods to feed the growing population in such countries is receiving increasing attention of the food scientists and nutritionists. Several international agencies and governmental programs in developing countries are confronted with a challenging task of alleviating the so-called protein calories malnutrition problem (Singh and Singh, 1991).
1.4 Aim and Objectives of Study
The aim of the study is to examine the Production and Sensory Evaluation of the Blend of Cow Milk and Soya Milk to Yoghurt. In achieving this aim, the following specific objectives were laid out as follows:
- To assess the effect of addition soymilk to goat’s milk at three different concentrations on chemical and organoleptic characteristics and shelf life of the product.
- To investigate the juice addition effect on the different concentrations of three fruits on chemical organoleptic and shelf life.
- To examine the utilization of Gum Arabic at two levels on chemical organoleptic and shelf life.
1.5 Justification of Study
Yoghurt is dairy product obtained by lactic acid fermentation as an action of starter culture contained of Lactobacillus delbrueckiissp. bulgaricus and Streptococcusthermophiles, and with addition of probiotics, it becomes powerful functional food. It is prepared from fresh whole or skimmed milk, boiled and concentrated by evaporation.
