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Evening program-1st SemesterMaster in Nutritional science and Food

Technology

Course Title: Food Processing and Preservation

Technology (Assignment)Course No: 5015

Group--BSession: Summer-(2013-14) Batch-B01

Submitted to:Md. Hafizur Rahman (Assistant

Professor)

Submitted by:S. M. Mainul IslamRoll: 130-116-079

Department of Applied Nutrition and Food Technology (ANFT)

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FACULTY OF APPLIED SCIENCE AND TECHNOLOGY

ISLAMIC UNIVERSITY, KUSHTIA-7003

Define Microwave : Micro waves are method of heating foods by employing radiant energy which affects foods when their energy is absorbed. The word Microwave means very short wave, which is the shortest wavelength region of the radio spectrum and a part of the electromagnetic spectrum.Microwave heating of foods is attractive due to its volumetric origin, rapid increase in temperature, controllable heat deposition, and the easy clean-up opportunities Microwave heating as one method of thermal food processing is presented. The current and potential uses of microwave heating in the food industry are many and are of growing importance

How does microwave work?Microwaves interact with polar water molecules and charged ions. The friction resulting from molecule alignment and migration of charged ions in rapidly alternating electromagnetic field generates heat within foods. US Federal Communication Commission (FCC) allocates 915 MHz and 2450 MHz bands for microwave heating applications.Most processed shelf-stable high moisture foods today are heat treated with pressurized hot water or steam to kill bacteria. Prolonged exposure to high temperature leads to poor product quality. Microwave sterilization is a thermal process [1] that delivers thermal energy to foods under pressure to achieve inactivation of bacteria harmful for humans. Sharp reduction in processing time improves color, texture and other sensory attributes of foods while meeting microbial safety requirements.WSU has received FDA acceptance of a microwave sterilization process for mashed potato. Currently, WSU researchers are generating scientific and engineering information to support regulatory acceptance of microwave sterilization technology for other products.

Properties of microwaveProperties of microwaves:

1. Microwaves are electromagnetic waves of radiant energy, differing from such other electromagnetic radiation as light wave and radio waves only in wave length.

2. Microwaves falls between radio waves and infrared radiant’s with wave length range from 25 million to 75 billion nm.

3. Microwaves like all electromagnetic radiation travels in a wave pattern4. The waves are reflected by metals but pass through with air, glass, paper, plastics and absorbed by

foods5. Most microwave container is designed to design to transmit microwave energy without reflecting or

absorbing it.6. Micro wave will travel through the container to the food7. When food is exposed to microwave is absorbed and convert it to heat8. Food composition mainly water in the key factor to determine how fast it will heats in the microwave

environments.

Difference between microwave woven & conventional oven methods,

Conventional MicrowavesHeat is conducted from external source Heat is produce inside the foodWater is not essential Water is essentialConventional methods brown or crust foods on the surface

Not

Heat generates from different source Heat generates from microwave & electricityFood substance direct contact with heat element Not

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and hot plateHeat sources causes food molecules to react large from the surface In word

Microwave penetrated food pieces uniformly