ABSTRACT
Soyabean
(Glycine max (L) ) cheese analog was produced from soymilk using glacial acetic
acid precipitation or coagulation of the milk protein. The unit operations
involved in the production of the cheese analog from soyabean seeds include:
screening, soaking, blanching, milling, filtering, warming, acidifying,
harvesting the curd, salting at 20g/1kg, pressing, waxing and aging .
The
cheese analog was chemically evaluated according to standard methods. The
product showed 41.78% moisture, 36.47% protein, 6.50% fat, 10.38% Ash, 4.87%
carbohydrate, 0.093% potassium, 0.402% sodium, 0.233% calcium, 0.036%
phosphorus. The protein, fat, and moisture levels of the cheese analog were
within the range of similar conventional cheeses.
The
microbial evaluation showed that 10 colonies of organisms were present in 101
dilution which is of a very considerable number. The heat treatment, acid added
and even the salt added showed that the organisms present are not pathogenic.
The
economic evaluation of the cheese analog showed that it could be a cheap source
of protein with real or perceived health benefits such as low level of fat and
cholesterol.
CHAPTER ONE
1.0 INTRODUCTION
Cheese
is a food product made form the curd of the milk of cows and other animals such
as goats, sheep, buffalo and so on, to give characteristics flavour differences.
(Potter and Hotchkiss, 2006; Nester et al, 1996). Cheese analog is also
referred to as cheese substitute or imitation cheese and is increasingly
entering the market place. They commonly have all or some of their milk fat
replaced with vegetable fat and vegetable protein (Potter and Hotchkiss 2006).
Cheese making is a very old process and still
retains some aspects of an art even when practiced in the most modern plants.
Part of this is due to the natural variation common to milk and the imperfect
controllability of microbial populations. Even with today’s modern production
methods, the manufacture of fine cheeses has remained essentially the same,
requiring experience, timing, and patience (Potter and Hotchkiss, 2006; Nester
et al).
It is believed that cheese making originated
in Asia over 8,000 years ago. The Romans improved the production of cheeses
during their occupation in Europe from 60B.C to A.D 300 (Nester et al, 1996).
The largest producer of cheese is the United States, accounting for 30 percent
of world production, followed by Germany, and France. The biggest exporter, by
monetary value, is France, then Germany (although it is first by quantity). The
world’s largest consumer (per capital) of cheese is Greece, followed by France
and Italy consuming 27.3kg, 24kg, and 22.9kg respectively by each citizen (in
the U.S the consumption of cheese is quickly increasing and has nearly tripled
between 1970 and 2003 and consumption per person has reached 14.1kg (31 pounds)
in 2003 (http://en.wikipedia.org/wiki/cheese).
Cheese can be broadly described or
categorized as acid or rennet cheese, and natural or process cheese. Of these
however, there are basically only about 18 distinct types of natural cheeses,
reflecting the different processes by which they are made (Potter and
Hotchkiss, 2006). The same initial steps are used to make most cheeses. First
milk is inoculated with a starter culture containing lactic acid bacteria. It
is then allowed to incubate until fermentation of the milk sugars produces a
critical level of lactic acid. At that time, the enzyme, rennin, which
coagulates the milk proteins is added. The coagulated proteins, or the curd is
separated from the liquid portion called the whey. The curd can be subjected to
further microbial processes, known as ripening or curing that result in characteristic
texture and flavor changes (Nester et al), salting, low oxygen, acidity and
presence of microbial metabolite propionic acid inhibit the growth of
pathogens. Ripening stage in cheese making differs from one cheese to another,
and ranges from weeks, months, to years. In United States of America, cheese
made from unpasteurised milk must be ripened for 60days in order to kill nay
pathogenic bacteria that must be
present. Regardless of the type of cheese being produced,both the fermentation and
ripening processes must be monitored to guard against undesired flavours,
textures, and appearances that result from the activities of contaminating
micro-organisms (Nester et al,1996).
In general, cheese is a good source of
calcium, protein and phosphorus. It has also been found to have positive effect
on sleep. Although cheese is often avoided by those who are lactose tolerant,
but ripened cheese like Cheddar contains only about 5%, and aged cheese, none.
Micro organisms involved in cheese making
include Lactobacillus lactics, Lactobacillus bulgaricus,
Streptococcus cremoris, Streptococcus thermophilus,Leuconestoc
citrovorum among others (Nester et al, 1996).
Soyabean is the best source of vegetable
protein for all including growing children and babies. According to Obiegbuna
and Morah, the bean is generally not eaten in the fresh state but as processed
product. This is because its nutritive value is improved by processing into
products such as soymilk, soyflour, roasted soyabean curd. Soymilk, like animal
milk, is used in the manufacture of other food product due to its functional
properties and nutritive value. Local processors of soymilk, rather than
discarding the unsold milk at the end of the day due to lack of refrigeration
facilities, coagulate it into curd using limejuice. This coagulated product
known as tofu, has found acceptances as a higher protein food for human
consumption and has been used as a protein source in the orient for many
centuries (Obiegbuna and Morah, 2001).
Despite the intrinsic beany flavour of
soyabean and gained wide acceptances, utilization is limited due to short shelf
life. Various coagulants are used in curdling or coagulating soymilk such as
lime juice, acetic acid, calcium chloride, of which lime juice is the most
common coagulant available to local processors in Nigeria (Obiegbuna and Morah,
2001).
Apart from soyabeans, cheese analog can be
gotten from rice, almond, nutritional yeast, groundnut as well as other
non-diary ingredients. It is available in many of the same varieties as its
diary counterpart. The incentives for developing such product are lower cost,
ready available of substitute ingredients, changing consumer tastes, and real
or perceived health benefits such as reduced level of fat, cholesterol, and
sodium. (Potter and Hotchkiss,2001).
The aim of this work is to know the proximate
composition of cheese analog made from soyabean milk using acid coagulation
method and to know its health benefits to man when consumed. This work is
carried out because as a vegetable plant source, soymilk is less expensive when
compared to milk which is of animal origin and as well as its level of
availability to man.
Soyabean is known to be good source of
vegetable milk processing of soymilk will expand its utilization as a source of
milk and cheese as a source of protein to the Nigeria population. Milk from
soyabean will also be a weapon against protein malnutrition in this country.
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