Food - Technology :  Food technology is a branch of food science that deals with the production processes that make food and the operations that are implemented on the food.

Food technology uses and exploits the knowledge of food science. Food technology use the information generated from food science i.e. where food must be grown, stored, processed, preserved, transported, packaged and distributed on a large scale.

Some general subjects offered in the course of Food Technology: 

1. Fundamentals of  Food Processing 
2. Food Biochemistry
3. Food Microbiology
4. Safety laws and regulations associated with the food
5. Food Hygiene and Sanitation
6. Fruit and Vegetable Processing 

1. Fundamentals of food processing  

    Introduction : Food Processing is the set of techniques or methods that are used for transformation of raw materials into food or of food into other food materials for consumption by humans and animals either in home (small scale) or in industry level (large scale).

        In Food processing typically clean, harvested crops or slaughtered and butchered animal products are taken and these are used to produce attractive, marketable and often long shelf-life food products. It is a way implemented to convert raw food stuff into well-cooked and well preserved eatables for both the humans and the animals.These methods are used by food processing industry to produce processed or preserved foods for our daily consumption.

         Best quality harvested, slaughtered and butchered and clean constituents are used by food processing industry to manufacture very nutritious food products.
 

High Temperature processing: (Thermal Processing)

It is defined as specific temperature and time combination which is required to inhibit the growth of microorganisms in food material.

Some examples of thermal processing are pasteurization, sterilization,blanching, canning, frying, baking and roasting.

Thermal processing are necessary in order to :

• Reduce the microbiological flora present in the food
• Avoid any change produced in the food by micro-organisms
• Apply the appropriate amount of heating/cooling to the food

Pasteurization : Pasteurization is a heat treatment given to the liquid food at a specific time and temperature combination.

It implies the destruction by application of heat of all those microorganism in vegetative state which would produce illness. And it reduces the number of microorganisms which would produce alteration in the food stuff.

Types of Pasteurization : 

1) In bottle Pasteurization
2) Batch/Holding/LTLT Pasteurization
3) HTST Pasteurization
4) Vacuum Pasteurization
5) Stassinization
6) Ultra high temperature Pasteurization
7) Uperization

In Bottle Pasteurization

• Tightly sealed bottles with special caps
• 63-66°C for 30 min

Advantages

1. Prevents post pasteurization contamination

Disadvantages

1. Heat transfer slow
2. Risk of bottle breakage
3. Oversized bottles have to be used

Batch/Holding/LTLT Pasteurization

• 63-66°C for 30 min n immediate cooling to 5°C or below.
• Heating is done indirectly.
• Three types:

1. Water Jacketed vat
2. Water spraying type
3. Coil vat type

High temperature short time

• Product is heated at 72 °C for 15 sec

Advantages

1. Less floor space
2. Low initial cost and operating cost
3. easy cleaning and sanitization
4. Development of thermophiles is not a problem
5. Process can be interrupted and restarted quickly

Disadvantages

1. Its not good for small quantities
2. complete drainage is not possible
3. Greater accumulation in holding section
4. Gaskets require constant attention

Vaccum Pasteurization

1. Pasteurization under reduced pressure by direct steam
2. To prevent the losses of volatile flavours
3. First Chamber - 5" hg & 90-95 °C
4. Second Chamber - 15-20" hg & 71-82 °C
5. Third Chamber - 26-28" hg & 43 °C

Stassanization

• Carried out in a tubular heat exchanger having concentric tubes
• Passing a milk through narrow space of 0.6-0.8 mm
• 74 °C for 7 seconds and then immediate cooling

Ultra High temperature Pasteurization

• 135-150 °C for fraction of a second
• Its success depends upon aseptic packaging

Uperization

• Shortened form of Ultra high temperature process
• heated with direct steam up to 150 °C for fraction of a second

Process Flow Chart

      CLARIFICATION ----> CHILLING & STORAGE ----> HEATING (50 °C) 

      ----> DEAERATION --->HEATING (80-90 °C) ----> UPERIZATION CHAMBER 

      ----> HIGH PRESSURE STEAM @ 150 °C (.33-.75 SEC) ----> EXPANSION CHAMBER

      ----> COOLING ----> STORAGE

Blanching : Blanching is a cooking process in which the food substance usually a fruit or vegetable, is plunged or dipped into boiling water for a certain temperature-time combination after which it is dipped in a cold water to stop the overcooking.

It stops enzyme activity which can cause loss of flavour, colour and texture. It cleans the surface of the fruit and vegetable, brightens the colour and minimize the loss of vitamins. It makes vegetables soft, which make it easy for packaging.

Thomas Keller says "Blanching vegetables is not hard-you have to decide to do it." These are some tips for perfectly crisp-tender vegetables:

1. Use a large quantity of water relative to the amount of vegetables you're blanching.
2. Use a lot of salt - about a cup of salt per gallon of water.
3. Stop the vegetables from overcooking them by plunging into a large amount of ice water.

Water Blanching:
In this type of blanching a blancher is used which has a blanching basket and a cover. In hot water blanching food is hold in 70°-100°C for a certain period of time and then it is removed to dewatering cooling section.
Hot water blancher developed by Hallstrom el. al., 1988

Steam Blanching:
It is recommended only for a few vegetables like broccoli, pumpkin and sweet potatoes.Steam blanching takes usually 1.5 times longer than that of water blanching.
Advantages of steam blanching:
• faster and more uniform heating
• good mixing of the product
• shorter processing times and hence smaller losses of vitamins and other soluble heat sensitive components of food
A steam blancher developed by Lazer et. al.,1971

By - Kamal Thakur and Naina Dilaik