Tag: #whey

CHEESE- introduction and production

Cheese is a most commonly used dairy product which is a product derived from milk. Cheese is available in the market in various textures, forms and flavors. It is basically the product of coagulation of milk protein, casein. Cheese is said to be a concentrated form of two major products i.e. Milk protein (casein) and Milk fat. Combination of these two results in the production of cheese which is very much liked by everyone nowadays.
The other ingredients of cheese besides milk are a particular, selective strain of a bacterium, a milk clotting agent and some amount of sodium chloride (to give a salty flavor).
Various types of cheese are present in the market which is basically due to the variation in its basic constituents. No new ingredient is actually added in forming the new type of cheese. Just a basic variation in the already present ingredients can help. Sometimes there is a need to add new additional ingredients which give rise to completely different variety of cheese. It has also been observed and noted that the change in any environmental conditions surrounding the manufacture and subsequent ripening of cheese also affects its manufacturing and thus type.
BASIC CHEESE MANUFACTURING PROCESS –
The basic cheese manufacturing process consists of 3 main stages – Curdling, Curd processing and ripening. All different varieties of cheese can be manufactured at different levels of manufacturing means some cheese can be made in the first step while some needs all the 3 steps to completely occur.

  1. CURDLING –
    It is the first and the most important step in the production of cheese. In this step, there is a separation of milk into solid curds and liquid whey. Usually, this step is achieved by the addition of acidifying (souring) agent in milk and adding the enzyme RENNET. The acidification can also be achieved by directly adding some acidic agent such as vinegar. But most commonly for this acidification purpose, a starter bacteria is used which converts milk sugars into lactic acid and without even the addition of any acidic substance, the acidification is achieved. The common starter bacteria which are used are from Lactococcus, Lactobacillus, or Streptococcus families. Swiss cheese requires the addition of Propionibacter Sherman, which is used to produce Carbon dioxide bubbles during ageing resulting in the hole like structure of Swiss cheese.
    Some fresh cheeses are curdled only the acidification process, but most cheeses require the addition of enzyme, rennet which sets the cheese as strong and rubbery. It also allows the curdling step at low acidity.
  2. CURD PROCESSING
    Till this step, the cheese has now set into a very moist gel. Some soft types of cheeses are essentially complete in the first step. They are just drained, salted and packaged. But from other cheeses, which are not been prepared in the single step, the curd is cut into small cubes which allows the remaining water to drain off from the individual pieces of curd itself.
    Some harder cheeses are then heated at a normal temperature which deliberately forces out the whey from the cut curds. This step changes the taste and flavor of the cheese. Apart from providing a salty flavor to cheese, salting has some other benefits also like it prevents cheese from spoiling, it drains out moisture and also it is used in firming he cheese’s texture in an interaction with its proteins. Different cheeses have different processes of getting texture.
  3. RIPENING
    Most of the cheeses are already prepared in the last step, some of which are not prepared yet are of harder varieties and more rubbery in texture which is completely attained in this step. In this step, the cheeses are left to rest under controlled conditions. This step is also known as AGING. This step may take several years to complete. As a cheese ages, the microbes and the enzymes secreted by them transform its texture and also intensify the flavor. This transformation is more of a result of the breakdown of casein proteins and milk fat into a complex mixture of amino acids, amines and fatty acids.

YOGURT- a fermented milk product

Yogurt is a basic fermented milk product that usually contains the basic bacterial starter cultures of Lactobacillus bulgaricus and Streptococcus thermophillus.
Although the composition of different types of yogurts changes but there is some fixed composition of fats present in them. It is important to note that all yogurts must contain at least 8.25% of solid which is not fat. The fat composition changes with the type of yogurt like full fat yogurt must contain not less than 3.25% of milk fat whereas low fat yogurt must not contain more than 2% milk fat. Also there is a category of non fat yogurt where the fat composition is even less than 0.5%.
The yogurt is basically a mixture of milk and cream which is then fermented by using a culture of Lactic acid producing bacteria. The types of milk which can be used are whole, reduced-fat, low-fat or non-fat depending on which the type of yogurt is decided. The lactic acid produced by the starter culture bacteria is basically responsible for lowering the pH of the yogurt making it acidic and tart. This finally causes the milk protein to thicken. These bacteria ferment the milk which results in the production of yogurt leads to partial digestion of the milk making it more easily digestible. In addition, these bacteria also act as a beneficial microorganisms for the human body as they act as oral-antibiotic therapy and helps in eliminating the pathogenic-bacteria from the gut and replenishing the non-pathogenic bacteria.


Ingredients of yogurt –
Milk
Cream
Sweeteners (e.g. sugar, honey, aspartame, etc)
Flavorings (e.g. vanilla, coffee, etc)
Other ingredients (e.g. fruits, preserves, stabilizers such as gelatin)

Types of yogurt –

  1. Set yogurt – This type of yogurt has a jelly-like structure and texture and is incubated and cooled in a final package.
  2. Stirred yogurt – This type is less firm than set yogurt. It is incubated in a tank and final coagulum is broken by stirring before cooling.
  3. Drinking yogurt – It also has coagulum broken before cooling though very little reformation of coagulum will occur.
  4. Frozen yogurt – This type of yogurt is incubated in the same way the stirred yogurt is incubated. It has an ice-cream like texture.
  5. Flavored yogurt – In this type of yogurt, flavors are added just before yogurt is poured into pots and the sugar content present in this type of yogurt is about 50%.

General processing of yogurt –

  1. Adjusting milk composition and blending all the ingredients
  2. Pasteurization of milk (at 85 degrees celcius for 85 minutes)
  3. Homogenization of milk (2000-2500psi)
  4. Cooling of milk to 42 degree celcius
  5. Inoculation with bacterial starter cultures into the cooled milk
  6. pH reduction by waiting for sometime
  7. Again cooling to 7 degree celcius
  8. Addition of fruits and flavors
  9. Packaging of prepared yogurt.

Health benefits of yogurt:
• Yogurt is comparably easier to digest than milk.
• It is rich in variety of vitamins.
• It is a rich source of protein.
• As it is source of protein, it may help in losing weight and gain muscles.
• It acts as a booster for immune system
• It is also important and useful for digestive system. It destroys the pathogenic microorganisms from the gut.
• It is good for bones especially for kids and elderly
• It may also be useful in lowering the blood pressure.