Determination of concentration of lactic acid in cow milk and soya beans

CHAPTER ONE
BACKGROUND OF THE STUDY
INTRODUCTION
1.0 SOYA BEANS
Soybeans, (Glycine max), also called soja bean or soya bean, annual legume of the pea family (Fabacea) and its edible seed. The soybean is economically the most important bean in the world, providing vegetable protein for millions of people and ingredients for hundreds of chemical products Wikipedia (2009). The origins of the soybean plant are obscure, but many botanists believe it was first domesticated in central China as early as 7000 BCE. An ancient crop, the soybean has been used in China, Japan, and Korea for thousands of years as a food and a component of medicines. Soybeans were introduced into United States in 1804 and became particularly important in the South and Midwest in the 20th century. Brazil and Argentina are also major producers.
According to Lessire M., Lebas F., 2017, Soybeans is an erect branching plant can reach more than 2 metres (6.5 feet) in height. The self-fertilizing flowers are white or shade of purple. Seeds can be yellow, green, brown, black, or bicolored, though most commercial varieties have brown or tan seeds, with one to four seeds per pod. In the United State the majority of soya bean crop are genetically modified for resistance to the herbicide glyphosate. The soybean may be cultivated in most types of soil, but it thrives in warm, fertile, well-drained, sandy loam. The crop is planted after all danger of frost is past. Soybeans are usually harvested mechanically, after leaves have fallen off the plant and the moisture content of the seed has dropped to 13 percent, permitting safe storage. Like other legumes, the plant add nitrogen to the soil by means of nitrogen-fixing bacteria and historically has been an important soil-enriching crop, though this practice is not common in most industrial agriculture system.
According to Heuze V., (2017) soybeans is one of the richest and cheapest sources of protein and it is stapled in the diets of people and animals in numerous parts of the world. The seed contain 17 percent oil and 63 percent meal, 50 percent of which is protein. Because soybeans contain no starch, they are a good source of protein for diabetics. In East Asia the bean is extensively consumed in the forms of soy milk, whitish liquid suspension, and tofu, a curd somewhat resembling cottage cheese.
Soybeans are also sprouted for use as a salad ingredient as a vegetable and may be eaten roasted as a snack food. Young soybeans, known as edamame, are commonly steamed or boiled and eaten directly from the pod. Soy sauce, a salty brown liquid, is produced from crushed soybeans and wheat that undergo yeast fermentation in salt water fir six months to a year or more; it is a ubiquitous ingredient in Asian cooking. Other fermented soy foods include tempeh, miso, and fermented bean paste.
Shurtleff, William; (2009). Modern research has led to a remarkable variety of uses for the soybean. Its oil can be processed into margarine, shortening, and vegetarian cheeses. Industrially, the oil is used as an ingredient in paints, adhesive, fertilizers, sizing for cloth, linoleum blacking, and fire extinguisher fluids, among other products. Soybean meal serve as a high-protein meat substitute in many food products, including baby food and vegetarian foods, and can be imparted with a meatlike texture for increasing the cooked yield of ground meats.
Nigeria is the largest producer of soybean in West Africa, and its major producing states are Kaduna, Niger, Kebbi, Nasarawa, Kwara, Oyo, Jigawa, Taraba, Borno, Benue, Bauchi, Lagos, Sokoto, Plateau, Zamfara and Abuja FCT.
Soybean is also called Glycine max, it’s among the species of legume and widely grown for its edible bean which has numerous uses. In Nigeria, it grows majorly in the middle belt accounting for 65-75% of the production in Nigeria.
Soybean are grown from seed planted in rows in the field and can grow well on a wide variety of soil and climates. It takes about 4-7 days after planting to start growing and about 90 and 150 days after sowing to nature.
The pod of soya beans is usually green but turns yellowish brown when nature with the beans being hard and dry. Also there are other varieties of soya beans which are black, brown or green colored, although varieties are rate.
After the soybeans are harvested, it is separated into pods and stems and can either be further processed or sold. The pod contains the soya beans, from which soya bean oil can be gotten from, and is done by cracking of the soybeans and subjecting it to heat at about 60oC – 88oC.
A solvent mainly hexane is added to extract the oil leaving behind the soya bean cake. The oil is then refined, blended, bleached and maybe on some occasions hydrogenated, it can serve as a vegetable oil or as a biodiesel fuel when further processed.
Soybean is among the world’s healthiest foods and has numerous health benefits such as;
• It contains vitamins and mineral like vitamin B and is also a good protein, iron and calcium source.
• Helps in the reduction of hot flash symptoms as experienced mainly by women in their menopause and peri-menopause stage.
• Aids in the prevention of type 2 diabetes and other chronic health issues by reducing the resistance of insulin in the body and at the same time increasing the synthesis of the insulin receptors.
• It helps in suppressing appetite thereby eliminating the possible chances of feeling hungry or overeating which in turns help in weight loss and healthy weight gain too because of the presence of fiber and protein content.
• It is also good for the heart, digestive systems, bones, controlling of the thyroid hormone especially when it come to goiter ad numerous others.
1.11 NUTRITIONAL CONTENT OF SOYBEAN
Soybeans contain about 18% oil and 38% protein Sneller CH (2003). Because soybean are high in protein, they are major ingredient in livestock feed. Soybeans are processed for their oil meal (for the animal feed industry). A smaller percentage is processed for human consumption and made into products including soy milk, soy flour, soy protein, tofu and many retail food products. Soy beans are also used in many non-food (industrial) products.
1.12 FOOD FOR HUMANS
Nearly all soybeans are processed for their oil. Soy processors (such as Cargill & ADM) take the raw soybeans and separate the oil from the meal. The oil may be refined for cooking and other edible uses, or sold for biodiesel production or industrial uses. The processors bake the high-protein fiber that is left after oil is removed and sell it for animal feed.
‘Soybean oil is used in cooking and frying foods. Margarine is a product made from soybean oil. Salad dressing and mayonnaise are made with soybean oil.
Some foods are packed in soybean oil (tuna, sardines, etc.) Baked breads, crackers, cakes, cookies and pies usually have soy bean oil in them.
1.13 FEED FOR ANIMALS
The high-protein fiber (that which remain after processing has removed the oil) is toasted, and prepared into animal feed for poultry, pork, cattle; other farm animals and pets. The poultry and swine industries are major consumers of soybean meal. Over half of the soybeans processed for livestock feed are fed to poultry, about one-quarter is fed to swine, and the rest is used for beef cattle, dairy cattle and pet food.
Soy protein is increasingly found in fish food, both for home aquariums and for the fish grown for cating. Most marine species were fed fish meal at one time, but the scarcity and increasing cost of fish meals has led producers to switch to high protein soymeal for a variety of marine species around the world, soy protein may be found in feed for most animal Battock M, Azam-Ali (1998). 1.114 OTHER USES
Biodiesel-biodiesel fuel for diesel engines can be produced from soybean oil by a simple process called trans-esterification. This process removes the glycerine from the oil, leaving soy biodiesel. Soy biodiesel is cleaner burning than petroleum-based diesel oil. It use reduces particulate emissions, and it is non-toxic, renewable and environmentally friendly.
Biocomposites are building materials made from recycled newspaper and soybeans. They replace other products traditionally made from wood, such as furniture, flooring, and countertops.
Particleboard, laminated plywood and finger-jointed lumber are made with soy-based wood adhesives.
Soy products are also found in many popular brands of home and commercial carpets, and in auto upholstery applications.
Soy oil produces environmentally friendly solvent that safely and rapidly removes oil from creeks, streams and shorelines without harming people, animals and the environment. Soy is an ingredient in many industrial lubricants, solvents, cleaners and paints.
Candles made with soybeans oil burn longer but with less smoke and soot.
SoyInk is superior to petroleum-based inks because soy ink is not toxic, renewable and environmentally friendly, and it cleans up easily.
Soy crayons made the Dixon Ticonderoga Company replace the petroleum used in regular crayons with soy oil making them non-toxic and safer for children.
Soy-based lubricants are as good as petroleum-based lubricants, but can withstand higher heat. More importantly, they are non-toxic, renewable and environmentally friendly.
Soy-based hydraulic fluid and rail flange lubricants are among the more recent products developed with check-off funds.
Soy-based foams are currently been developed for use in coolers, refrigerators, automotive interior and even footwear. Beginning in 2017, Ford Mustangs and other vehicles rolled off the production line with soy foam in the seats. New uses in the automotive and equipment industry followed, including lubricants, body parts and interiors and seating Hider, RC (2009).
1.2 LACTIC ACID
Lactic Acid is an organic acid. It has a molecular formula CH3CHOHCO2H (2 Hydroxyl propanoic acid). It is white in solid state and it is miscible with water. While in liquid state (dissolve state) it is a colorless solution. Production includes both artificial synthesis as well as natural source. Lactic acid is an alpha-hydroxyl acid (AHA) due the presence of carboxyl group adjacent to the hydroxyl group. It is used as a synthetic intermediate in many organic synthesis industries and in various biochemical industries. The conjugate base of lactic acid called lactate.
In solution, it can ionize a proton from the carboxyl group, producing the lactate ion CH3CH(OH)COO
Compared to acetic acid, its pKa is 1 unit less, meaning lactic acid is ten times more acidic than acetic acid. This higher acidity is the consequence of the intramolecular hydrogen bonding between the α-hydroxyl and the carboxylic group. Steinkraus KH (September 1983). Lactic acid is chiral, consisting of two enantiomers. One is known as L-(+)-lactic acid or (S)-lactic acid and the other, its mirror image, is D-(-)-lactic acid or (R)-lactic acid. A mixture of the two in equal amounts is called DL-lactic acid, or racemic lactic acid. Lactic acid is hygroscopic. DL-Lactic acid is miscible with water and with ethanol above its melting point, which is around 17 or 180C. D-lactic acid and L-lactic acid or racemic lactic acid. Lactic acid produced by fermentation of milk is often racemic, although certain species of bacteria produce solely (R)- lactic acid. On the other hand, lactic acid produced by anaerobic respiration in animal muscles has the (S) configuration and is sometimes called “sarcolactic” acid, from the Greek “sarx” for flesh. Enninga, H (2010).
1.3 FERMENTATION
Fermentation is a metabolic process that produces chemical changes in organic substrate through the action of enzymes. In biochemistry, it is narrow defined as the extraction of energy from carbohydrates in the absence of oxygen. In the context of food production, it may more broadly refer to any process in which the activity of microorganism brings about a desirable change to a foodstuff or beverage. The science of fermentation is known as zymology. Dusheck, Shurtleff W, (2004).
Fermented milk products are created when milk ferments with lactic acid bacteria, such as Lactobacilli or Bifidobacteria spp. The fermentation process makes the ferment with lactic bacteria acid bacteria, such as lactobacilli or Bifidobacterial spp. The fermentation process makes the fermented milk product easier to digest, especially for people who have milk allergies or are lactose-entolerant. Fermentation also increases the shelf-life of the product. Olympia MS (1992).
1.4 PURPOSE OF THE STUDY
This research study intends to achieve the following objectives
The main objectives are:
I. To determine the fermentation of soymilk and cow milk
II. To determine the percentage concentration of lactic acid in soya/cow milk
1.5 SIGNIFICANT OF THE STUDY
Soybean is an excellent source of protein is low in fat and cholesterol development of this new product will also lead to diversification of soybean use which in turn improve unitization of the soy beans. The milk is low cost product, which only involve fermenting the soymilk and only additive added in which is low concentration. Development of this product will encourage commercialization of the soy beans thus crating more market for soybeans and consequently improving its utilization.
1.6 SCOPE AND LIMITATION OF THE STUDY
This study investigated the concentration of lactic acid concentration in sample of soybeans milk in Gombe state.
1.7 PROBLEMS STATEMENT
Lactic acid is used extensively in the food industry and pharmaceutical industry for its acidifying and bacteriostatic properties. It results from sugar fermentation integrated by lactic bacteria.
When exposed to heat, the bacteria found in milk transform lactose into glucose and galactose then into lactic acid.
The acidity measure makes it possible to control the quality of cow milk. If the milk is not refrigerated and the lactic acid content matches 6 to 7g/l, casein coagulates and milk turn at an ambient temperature. Hence there is need to determine the concentration of lactic acid both in cow and soy beans milk. 
CHAPTER TWO
2.1 LITERATURE REVIEW
This is commonly used everyday life, an acid is usually regarded as a higher corrosive burning liquid, Layman take it as a substance that cannot be touched talk-less to eaten. However, cannot be generally regarded as non eatable completely because some are eatable while some are not because acid are of different kind based on the properties they exhibit.
In general, the word “acid” is derived from the word lactic acid meaning sour “sour” or “tort” and also related to the lactic word ace turn, meaning “vinegers” several theories have been made to answer the question what is an acid?
According to Sneller CH (2003) that an acid is a liquid body composed of small form of point particles slightly resembling find delicate needle. He conjecture that acid were sour because they consist of pointed or slickly particles that pricks ithe tongue. As early as Yang J, Cao Y, (July 2010) noted that a class of chemical compound existed that has similar set of properties different from those of other compounds. These substance are acids and among their properties which they exhibit ability of sour test, ability to change the color of vegetable dyes (indicator/litmus paper) they have high solvent power/dissolver ability some of them have the tendency to react with certain metal to evolve hydrogen.

    Date: 2026-08-05 00:00:00.000000