LPT 321: Meat Science (1+1)

FORMULATION AND DEVELOPMENT OF SURIMI

Raw material

• Fish having white meat and low fat content is generally used.
• Alaska Pollock (Theragra chalcogramma) has been the traditional material.
• Decline in the Alaska Pollock fishery has resulted in the producer countries increasingly using other species like Pacific Whiting, Hoki, Croaker, Lizard Fish, Barracuda, Ribbon Fish, Threadfin Bream etc.
• Even fatty fish has recently been employed after removing the fat with alkali washing.

Processing of surimi

• The basic steps of production of surimi are as follows :
• Heading and gutting
  • The head, viscera and most of the backbone of the fish are removed.
  • The kidney, intestines, parts of stomach and liver, if allowed to remain, may severely damage the quality of protein during processing.
  • Filleting before mincing reduces yield, but it increases the quality of surimi produced.
  • It has become a common practice now to install a filleting machine at the beginning of the surimi line.
• Mincing
  • Meat is separated from the skin and bones of the dressed fish by a mechanical deboner.
  • This is done by extruding the muscle through small perforations (3-5 mm dia) in a rotating stainless steel drum.
• Washing
  • The deboned mince is mixed with fresh water in a series of leaching tanks.
  • It is important to maintain the water/mince ratio at such a level that proper washing is performed without leading to overhydration.
• Refining
  • The refiner is a high speed rotating spiral surrounded by a screen having perforations of 1.2 mm to 3 mm.
  • The washed meat is forced through the perforations, leaving behind any impurities.
• Dehydrating
  • The water content of the washed and refined mince is further reduced in a screw press.
  • The screw press is a perforated drum of about 10 feet long, inside which rotates a spiral screw.
  • As the screw rotates, it pushes the meat down the length of the drum.
  • The dewatered material comes out through a chute at the end of the drum.
• Mixing with cryoprotectants
  • The dewatered mince is mixed with cryoprotectants like sugar, sorbitol and polyphosphates which prevent protein denaturation during frozen storage.
• Freezing
  • The prepared surimi is immediately frozen at -40°C in a contact plate freezer and stored at -20°C.

Processing yields at different stages

Stage of Operation	Yield
Raw material	100
Heading & gutting	60
Mincing	45
Washing	42
Refining	30
Dewatering	20