amsa - yoghurt

8/7/2019 amsa - yoghurt

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What¶s yoghurt??

Yoghurt is formed by the bacterial fermentation of milk. It can be made from

any milk, but cows milk is usually used. Bacteria cause the sugar in the milk to

ferment, that produces lactic acid. This then reacts with the protein in the milk

to form yoghurt.

History of yoghurt (yogurt)

The first evidence of yoghurt being eaten dates form 2500 BC.

Certainly the first yoghurt would have been discovered accidentally, with milk being left too

long in the sun or a warm place. How long it took before somebody announced that the rancidmilk had become a tasty dessert is less clear...

It is probable that the climate in India, Asia and southern Europe was responsible for yoghurt

being found there long before more cool climates. It has also been suggested that the nomadic

Bulgars perhaps found yoghurt spontaneously produced on their goatskin bags, and brought it

to Europe with them in the second century AD.

Yoghurt remained in India, Asia and southern / central Europe for the next couple of

thousand years, little known to the rest of the world.

It was early in the 20th century that the suggestion arose that Bulgarian peasants owed their long and healthy lives to the substantial amounts of yoghurt they ate, which was the first step

towards yoghurt conquering the world.

The second step was a business called Danone, the first commercial yoghurt producer.

Started in 1919, and still a very successful company to this day (better known under the

Dannon name in North America) the company successfully launched yoghurt on the world.

Yogurt is a dairy product, which is made by blending fermented milk with various

ingredients that provide flavor and color. Although accidentally invented thousands of yearsago, yogurt has only recently gained popularity in the United States.

It is believed that yogurt originated in Mesopotamia thousands of years ago. Evidence has

shown that these people had domesticated goats and sheep around 5000 B.C. The milk fromthese animals was stored in gourds, and in the warm climate it naturally formed a curd. This

curd was an early form of yogurt. Eventually, a process for purposely producing yogurt wasdeveloped.

While yogurt has been around for many years, it is only recently (within the last 30-40 years)that it has become popular. This is due to many factors including the introduction of fruit and

other flavorings into yogurt, the convenience of it as a ready-made break-fast food and the

image of yogurt as a low fat healthy food.

Manufacturers have responded to the growth in the yogurt market by introducing many

different types of yogurt including low fat and no-fat, creamy, drinking, bio-yogurt, organic,baby, and frozen. Traditional yogurt is thick and creamy. It is sold plain and in a wide

assortment of flavors. These are typically fruit flavors such as strawberry or blue-berry



however, newer, more unique flavors such as cream pie and chocolate have also beenintroduced. Cereals and nuts are some-times added to yogurts. Yogurt makers also sell

products with a varying level of fat. Low fat yogurt, which contains between 0.5% and 4%fat, is currently the best selling. Diet no-fat yogurt contains no fat at all. It also contains

artificial sweeteners that provide sweetness while still reducing calories. Creamy yogurt is

extra thick, made with whole milk and added cream. Drinking yogurt is a thinner product,

which has a lower solids level than typical yogurt. Bio-yogurt is made with a different type of fermentation culture and is said to aid digestion. Yogurt that is made with milk from specially

fed cows is called organic yogurt. This type of yogurt is claimed to be more nutritious than

other yogurts. Other types of yogurts include pasteurized stirred yogurt that has extended

shelf life, baby yogurt made specifically for children, and frozen yogurt.

The yogurt itself has a generally aldehydic flavor, which is a result of the fermentation

process. Since it is made from milk, yogurt is rich in nutrients. It contains protein and

vitamins and is a rich source of calcium. In fact, a small container of yogurt contains as much

calcium as a third of a pint of milk. In addition to these nutritional characteristics, yogurt is

also thought to have additional health benefits. One of the suggested benefits of yogurt is thatit acts as a digestive aid. In the body, it is thought that yogurt can encourage the growth of

beneficial bacteria in the gut. These organisms help to digest food more efficiently andprotect against other, harmful organisms. Another health benefit of yogurt is for people that

are lactose intolerant. These people have difficulty digesting milk products however, theytypically can tolerate yogurt.

Raw Materials

In general, yogurt is made with a variety of ingredients including milk, sugars, stabilizers,

fruits and flavors, and a bacterial culture (Lactobacillus bulgaricus). During fermentation,these organisms interact with the milk and convert it into a curd. They also change the flavor

of the milk giving it the characteristic yogurt flavor of which acetaldehyde is one of theimportant contributors. The primary byproduct of the fermentation process is lactic acid. The

acid level is used to determine when the yogurt fermentation is completed which is usually

three to four hours. The suppliers of these yogurt cultures offer various combinations of the

two bacterial types to produce yogurts with different flavors and textures.

To modify certain properties of the yogurt, various ingredients may be added. To make

yogurt sweeter, sucrose (sugar) may be added at approximately 7%. For reduced calorie

yogurts, artificial sweeteners such as aspartame or saccharin are used. Cream may be added

to provide a smoother texture. The consistency and shelf stability of the yogurt can be

improved by the inclusion of stabilizers such as food starch, gelatin, locust-bean gum, guar

gum and pectin. These materials are used because they do not have a significant impact on

the final flavor. The use of stabilizers is not required however, and some marketers choose

not to use them in order to retain a more natural image for their yogurt.

To improve taste and provide a variety of flavors, many kinds of fruits are added to yogurt.

Popular fruits include strawberries, blueberries, bananas, and peaches, but almost any fruit

can be added. Beyond fruits, other flavorings are also added. These can include such things as

vanilla, chocolate, coffee, and even mint. Recently, manufacturers have become quite

creative in the types of yogurt they produce using natural and artificial flavorings.

The Manufacturing Process



The general process of making yogurt includes modifying the composition of andpasteurizing the milk; fermenting at warm temperatures; cooling it; and adding fruit, sugar,

and other materials.

Modifying milk composition

y 1 When the milk arrives at the plant, its composition is modified before it is used tomake yogurt. This standardization process typically involves reducing the fat content

and increasing the total solids. The fat content is reduced by using a standardizing

clarifier and a separator (a device that relies upon centrifugation to separate fat from

milk). From the clarifier, the milk is placed in a storage tank and tested for fat and

solids content. For yogurt manufacture, the solids content of the milk is increased to

16% with 1-5% being fat and 11-14% being solids-not-fat (SNF). This is

accomplished either by evaporating off some of the water, or adding concentrated

milk or milk powder. Increasing the solids content improves the nutritional value of

the yogurt, makes it easier to produce a firmer yogurt and improves the stability of the

yogurt by reducing the tendency for it to separate on storage.

Pasteuriz ation and homogeniz ation

y 2 After the solids composition is adjusted, stabilizers are added and the milk is

pasteurized. This step has many benefits. First, it will destroy all the microorganisms

in the milk that may interfere with the controlled fermentation process. Second, it will

denature the whey proteins in the milk which will give the final yogurt product better

body and texture. Third, it will not greatly alter the flavor of the milk. Finally, it helps

release the compounds in milk that will stimulate the growth of the starter culture.

Pasteurization can be a continuous-or batch-process. Both of these processes involve

heating the milk to a relatively high temperature and holding it there for a set amount

of time. One specific method for batch process pasteurization is to heat a large,

stainless steel vat of milk to 185° F (85° C) and hold it there for at least 30 minutes.

y 3 While the milk is being heat treated, it is also homogenized. Homogenization is a

process in which the fat globules in milk are broken up into smaller, more consistentlydispersed particles. This produces a much smoother and creamier end product. In

commercial yogurt making, homogenization has the benefits of giving a uniformproduct, which will not separate. Homogenization is accomplished using a

homogenizer or viscolizer. In this machine, the milk is forced through small openingsat a high pressure and fat globules are broken up due to shearing forces.

F erment ation

y 4 When pasteurization and homogenization are complete, the milk is cooled to

between 109.4-114.8° F (43-46° C) and the fermentation culture is added in aconcentration of about 2%. It is held at this temperature for about three to four hourswhile the incubation process takes place. During this time, the bacteria metabolizes

certain compounds in the milk producing the characteristic yogurt flavor. Animportant byproduct of this process is lactic acid.

y 5 Depending on the type of yogurt, the incubation process is done either in a largetank of several hundred gallons or in the final individual containers. Stirred yogurt is

fermented in bulk and then poured into the final selling containers. Set yogurt, alsoknown as French style, is allowed to ferment right in the container it is sold in. In both



instances, the lactic acid level is used to determine when the yogurt is ready. The acidlevel is found by taking a sample of the product and titrating it with sodium

hydroxide. A value of at least 0.9% acidity and a pH of about 4.4 are the currentminimum standards for yogurt manufacture in the United States. When the yogurt

reaches the desired acid level, it is cooled, modified as necessary and dispensed into

containers (if applicable).

Adding other ingredients

y 6 Fruits, flavors, and other additives can be added to the yogurt at various points in

manufacturing process. This is typically dependent on the type of yogurt being

produced. Flavor in non-fruit yogurts are added to the process milk before being

dispensed into cartons. Fruits and flavors can also be added to the containers first,

creating a bottom layer. The inoculated milk is then added on top and the carton is

sealed and incubated. If the fruit is pasteurized, it can be added as a puree to the bulk

yogurt, which is then dispensed into containers. Finally, the fruit can be put into a

special package, which is mixed with plain yogurt upon consumption.

y 7 The finished yogurt containers are placed in cardboard cases, stacked on pallets, and

delivered to stores via refrigerated trucks.

Quality Control

Milk products such as yogurt are subject to a variety of safety testing. Some of these includetests for microbial quality, degree of pasteurization, and various forms of contaminants. The

microbial quality of the incoming milk is determined by using a dye reaction test. Thismethod shows the number of organisms present in the incoming milk. If the microbial count

is too high at this point, the milk may not be used for manufacture. Since completepasteurization inactivates most organisms in milk, the degree of pasteurization is determined

by measuring the level of an enzyme in the milk called phosphatase. Governmental

regulations require that this test be run to ensure that pasteurization is done properly. Beyondmicrobial contamination, raw milk is subject to other kinds of contaminants such as

antibiotics, pesticides or even radioactivity. These can all be found through safety testing and

the milk is treated accordingly.

In addition to safety tests, the final yogurt product is also evaluated to ensure that it meets the

specifications set by the manufacturer for characteristics such as pH, rheology, taste, color,and odor. These factors are tested using various laboratory equipment such as pH meters and

viscometers and also human panelists.

The Future

The future of yogurt manufacturing will focus on the development of new flavors and longer lasting yogurts. The introduction of new flavors will be driven by consumer desires and new

developments by flavor manufacturers. The suppliers of the bacterial cultures are conductingresearch that hints at the development of uniquely flavored yogurts. By varying the types of

organisms in the cultures, yogurt is produced much faster and lasts longer than conventionalyogurt.

Additionally, the nutritional aspects of yogurt will be more thoroughly investigated There is

some evidence that has shown consumption of yogurt has a beneficial antibiotic effect. It has



also been shown to reduce the incidence of lactose intolerance and other gastro-intestinalillnesses. Other purported benefits of yogurt include the reduction of cholesterol, protection

against certain cancers, and even boosting the immune system. The research is still notcomplete on these benefits however, these factors will likely be important in the continued

market growth of yogurt.

1. Step 1

Is frozen yogurt healthy when compared to ice cream?

If offered the choice between ice cream and frozen yogurt, in most cases, yogurtwill be the healthier alternative, although you'll need to read labels carefully toavoid surprises. Some "healthy frozen yogurt" can have a fat content of up to 15grams per cup which exceeds that of many ice creams. If choosing between alow fat ice cream and yogurt, unless you're selecting a healthy frozen yogurt, thelow fat ice cream could win out, depending upon the brand and the nutritionalprofile.

2. Step 2

When comparing frozen yogurt to standard ice cream, the yogurt will generallyhave the advantage. Most regular ice cream is ten to twelve percent fat by weigh twhile frozen yogurt varies from two to four percent. Keep in mind that many lowfat frozen yogurts compensate for the lower fat content by adding extra sugar.That low fat "healthy" frozen yogurt may not be such a good option if it hastwenty grams of sugar. Again, read the label before purchasing.

3. Step 3

Is frozen yogurt healthy when compared to regular yogurt?

When it comes to nutrition, standard yogurt seems to have the advantage over frozen yogurt. Frozen yogurt, as a generalization, is lower in calc ium and proteinthan yogurt found in the dairy case. In fact, the calcium content of regular yogurtis almost twice that of the frozen variety. Both standard and frozen yogurt can bequite high in carbohydrates since companies use sugar to add taste appeal . If you're concerned about the sugar content, look for brands of frozen yogurtwithout added sugar or brands that are sweetened with Splenda.

4. Step 4

Are there any additional health benefits of frozen yogurt?

One of the major benefits of healthy frozen yogurt is the probiotic content. Thereare frozen yogurts that advertise they contain live bacterial cultures which help topromote better digestion as well as give all of the other advantages these "goodbacteria" have to offer. It appears that these friend ly bacteria are able to survivethe freezing process required to make healthy frozen yogurt and still retain their ability to positively affect your gut. Look for a brand that advertises that it containslive cultures.



5. Step 5

Another additional health bene fit of healthy frozen yogurt over ice cream is thelactose found in frozen yogurt appears to be more digestible than the lactose inmilk. This is particularly important for people with lactose intolerance who mayexperience bloating and diarrhea after a la ctose load.

6. Step 6

The bottom line? Although frozen yogurt may not be as healthy as standardyogurt in terms of protein and calcium content, it does have some advantagesover ice cream including greater digestibility and the presence of probioticcultures in some brands. In terms of fat and sugar content, it pays to read labelsclosely.

BIKIN YOGHURT

To start, you need yogurt; so buy a small container of yogurt, the type you likeand make sure it matches the fat content of the milk you will use to make your yogurt.

1. Step 2

In a large pot heat up the milk until it reaches boiling point (212 °F). Then let themilk cool down. You can put the milk pot in cold water to speed up the coolingprocess. Check milk temperature that the milk has cooled down to about 110 -115°F, and not below before you continue.

2. Step 3

Take about a few spoonfuls of yogurt (I use 4 oz) and mix some milk to it. Thentake that mixture and pour into the large milk con tainer. Then pour the milk withthe mixed-in yogurt into two half gallon plastic containers (I use two Costco 40 ozMixed Nuts containers)and wrap them in a towel and put them on a shelf to letthe yogurt form in the slow cooling process from 115 °F. I keep the yogurt therefor 24 hours and then I refrigerate it. To make another batch, I just use a fewspoonful of yogurt from that batch to start a new batch. I can reuse the yogurt 3 -4times before it loses its "power" and the I start with a fresh set again. Enjoy

This leaves two questions:

y

are the benefits real?y are the benefits greater with yoghurt containing live bacteria than for pasteurised products?

The primary benefits of natural yoghurt are simply a result of the potassium, calcium, B12 and

other B vitamins and protein that it contains.

The claimed benefits of yoghurt include:

y reduced gastrointestinal infections

y improved immune system (resistance to illness and infection)



y greater resistance to cancer

y reduced incidence of osteoporosis (wekened bone strength)

Additional benefits include

y treatment of, and reduction of the symptoms of, thrush

y lactose intolerant people can often consume yoghurt, because the enzymes in the yoghurt

help reduce the lactose levels in the intestines - thus gaining the benefits contained in allmilk based products (above all calcium)

y improved absorption of calcium in the intestine, because the lactic acid in the yoghurtprovides the perfect environment for this absorption to occur

The benefits of live yoghurt over pasteurised yoghurt do not seem to be conclusively proven,despite strong evidence that they exist. However there is strong, if not inconclusive evidence, andmost nutritionists would recommend the 'live' version.

And the benefits of heat-treated yoghurt? These are

y a longer shelf-life, and hence more financially viable for the manufacturer

y a less bitter taste

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amsa - yoghurt