Freezing Technology

Teacher

Biswajit Mohanty

Category

Core Courses

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Course Name : Freezing Technology

FSPT 2103(1+1) : FSPT 2103(1-1-0)

Course Objectives

  • This course deals with the preservation of sea foods by chilling and freezing techniques. As we know, fish is a perishable commodity, its mainly because of the composition. Nearly 70% of the fish body constitutes water and 30% consist of protein, fat, minerals, and vitamin and non-protein nitrogen extractives. At ambient temperature fish muscle undergo rapid biochemical changes and creates a favorable environment for microorganisms to grow. This in turn responsible for the production of fouls smell and makes muscle spoiled and unsuitable for human consumption. Fish contains all essential amino acids (EAA) that is necessary for human body. Poly unsaturated a fatty acid (PUFA) (Omega-3-fatty acids) of fish is good for human health. Therefore it is imperative to preserve the fish immediately after catch to get the EAA & PUFA without any deterioration. How it can be preserved?. It is possible by lowering the temperature by direct (icing) or indirect (chill storage) methods. The main principle of chilling by ice is, it lowers the temperature of fish body from 30°C to 5°C. This greatly affect the mesophilic bacterial flora of fish and its growth is completely arrested by lowering of temperature and also slows down the biochemical activity, there by preserving quality to the extended time. Various methods of chilling is explained in detail. To consume the fish as similar to fresh fish, it has to be subjected to freezing process. Different methods of freezing fish, equipments used, refrigeration load and refrigerants used are discussed with illustration in detail. Before consuming, frozen fish has to be thawed to obtain fish in normal form. Various methods of thawing including latest techniques are described.

Learning Outcomes

Normally frozen fish will be stored in cold store where the temperature is maintained at -18°C. During storage due to various factors frozen fish undergo physical & chemical changes. Quality changes during storage, its preservative methods are explained cleanly storage condition is very important for best quality sea food. Therefore, the correct layout of cold store with all factors, mobile store (containers) was also described. Packaging of food is important in maintaining the wholesomeness of the product. Various types of packaging materials and their requirements were elaborated. To export the sea food it is essential to register the processing unit to European Union under their law. Therefore every approved unit must have a HACCP plan for that particular firm. Before preparing a plan one must know the classification of physical, chemical and biological hazards including Bio-toxin. All the above hazards are discussed in detail. Extension of shelf life by vacuum packing & Modified atmospheric packaging (MAP) were also documented. By undergoing this course one must learns the preservation technique by freezing and how to main the hygienic condition of the fish and export formalities, rules and regulations of importing countries. To consume the fish as similar to fresh fish, it has to be subjected to freezing process. Different methods of freezing fish, equipments used, refrigeration load and refrigerants used are discussed with illustration in detail. Before consuming, frozen fish has to be thawed to obtain fish in normal form. Various methods of thawing including latest techniques are described.

Course Syllabus

Freezing Technology     

Theory

Introduction to freezing technology; characteristics of fish and shellfish; changes in fish after death, spoilage of fish, spoilage and pathogenic microorganism. Handling of fresh fish; sanitation in processing plants. Principles of low temperature preservations. Chilling of fish – methods and equipment for chilling; icing – quality of ice, ice making; refrigerated or chilled sea water, chilling rate; spoilage of fish during chilled storage; use of antibiotics and chemicals. Freezing of fish fundamental aspects; heat units; freezing point depression, eutectic point; freezing rate; methods of freezing, freeze drying, physico– chemical changes that occur during freezing, mechanism of ice crystal formation; preparation of fish for freezing. Changes that occur during frozen storage – microbiological, physical and chemical changes, protein denaturation, fat oxidation, dehydration, drip; protective treatments – polyphosphate, glazing, antioxidants, packaging; thawing of frozen fish – methods of thawing. Transportation of frozen fish, cold chain, quality control, HACCP in freezing industry.

Practicals

 Sanitation and plant housekeeping; chilling and freezing equipment, instruments; packages and product styles; methods of icing fish; cooling rate; preservation by chilled sea water; freezing and thawing curves; freezing of different varieties of fish and shellfish; estimation of drip; determination of quality changes during frozen storage; inspection of frozen fishery products; visits to ice plants, cold storages and freezing plants.

Session Plan

Session 1

Introduction to freezing technology; characteristics of fish and shellfish; changes in fish after death, spoilage of fish, spoilage and pathogenic microorganism.

Session 1

https://www.youtube.com/watch?v=D8Npk0ZtxJg

Practical- Plant Hygiene and Sanitation

P1

Session 2

Chilling of fish – methods and equipment for chilling; icing – quality of ice, ice making; refrigerated or chilled sea water, chilling rate; spoilage of fish during chilled storage; use of antibiotics and chemicals.

Session 2

https://www.youtube.com/watch?v=9ztjEOk-tJQ

https://www.youtube.com/watch?v=0WxLLsviIRw

Session 3

Manufacturing of different types of Ice, Super chilling (0ºC to - 4ºC), Application of ozone / chlorine in seafood processing

Session 3

https://www.youtube.com/watch?v=dB6Dxsxb8Og

https://www.youtube.com/watch?v=Y2zdsLrFVb0

Session 4

Freezing preservation of fish, Physical, chemical and thermodynamic properties of  refrigerants

Session 4

https://www.youtube.com/watch?v=rRyo4WcIsMg

https://www.youtube.com/watch?v=jO1tHkoo4-Y

https://www.youtube.com/watch?v=bGdZWyEtYFY

Session 6

Types of freezer, Methods of protective treatments, Calculation of freezer refrigeration load

Session 6

https://www.youtube.com/watch?v=TPabv9iDENc

https://www.youtube.com/watch?v=0gv2tJf7nwo

Session 7

Freeze drying of fish, Thawing of fish, Quality changes during frozen storage, Microbial growth at low temperature.

Session 7

https://www.youtube.com/watch?v=vwtAuslmCkU

https://www.youtube.com/watch?v=_nLsoFNsxHk

https://www.youtube.com/watch?v=3qEwfIif89U

Session 8

Cold stores and containers, Refrigerated containers, Good handling and shipping practices

Session 8

https://www.youtube.com/watch?v=OwSSk1vF5ZI

https://www.youtube.com/watch?v=nMd9mahYoOg

https://www.youtube.com/watch?v=hKRL-HcSJx0

 

Session 9

Packaging methods, Packaging of frozen fishery products, Vaccum packaging and modified atmosphere packaging and storage

Session 9

https://www.youtube.com/watch?v=O1gQNkxkdCE

https://www.youtube.com/watch?v=juvZ-rtViK0

https://www.youtube.com/watch?v=mLXfZGAV5Gw

 

Session 10

HACCP, Physical, chemical and biological hazards in seafood, Important biotoxin in seafood, Histamine

Session 10

https://www.youtube.com/watch?v=j-XNzBUKOoE

https://www.youtube.com/watch?v=5oOhgJd046w

https://www.youtube.com/watch?v=-XZphYpRlyA

 

 

 

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