Seaweed in the Filipino Diet

Seaweed

• Seaweeds are naturally abundant in the Philippines
• Used in Filipino diet for years
• Classified into four classes based on pigmentation:
  • Chlorophyceae (green algae)
  • Cyanophyceae (blue-green algae)
  • Phaeophyceae (brown algae)
  • Rhodophyceae (red algae)
• Green and blue-green algae grow in freshwater
• Brown and red algae, commonly referred to as seaweeds, are found in marine habitats
• Main components of seaweed are carbohydrates (saccharides and cellulose), proteins, and minerals
• Contain lipids and vitamins
• Some seaweeds have high protein content, such as dried laver (Porphyra tenera)
  • Protein content reaches 34-40% comparable to soybean
• Rich in vitamins A, B1 (thiamine), B2 (riboflavin), C (ascorbic acid) and niacin
• High levels of minerals, including calcium, sodium, magnesium, potassium, phosphorus, sulfur, iodine, and iron
• Recent research suggests carrageenan (a type of seaweed extract) lowers blood glucose levels, making it beneficial for diabetics
• Carrageenan can bind with toxins, such as saxitoxin (red tide toxin), and remove them from the body

Fish Oils

• Extracted from specific fish species
• Obtained from fish waste materials during processing
• Some bony fish (mackerel, herring) have fat concentrated in their muscle tissue
• Sharks, rays, and skates have large oily livers, which may comprise 10-15% or more of their body weight.
• Fish oils are mainly esters of fatty acids and glycerol (triglycerides)
• Comprised of 25% saturated fatty acids (palmitic acid, stearic acid, myristic acid) and 75% unsaturated fatty acids (oleic acid)
• The unsaturated fatty acid chain length varies significantly

Fish Protein Concentrate (FPC)

• Classified by the Food and Agriculture Organization (FAO) into three types:
  • Type A: Odorless and tasteless powder with low fat content
  • Type B: Powder with a fishy flavor
  • Type C: Ordinary fish meal produced under hygienic conditions
• Types A and B preparation methods:
  • Chemical: Solvents like ethanol, isopropanol, sodium citrate, and sodium chloride are used
  • Enzymatic: Uses proteolytic enzymes (bromelin, papain, bacterial and fungal proteases) to digest fish protein
  • Physical: Physical processes like pressing to separate water and oil from whole fish
• Cost of fish is the main determining factor of FPC cost
• Inexpensive fish that are not in high demand for direct consumption are suitable for Type B FPC production

Minced Fish Processing

• Minced fish is a popular food product in Southeast Asia
• Used in various dishes like soups, noodles, rice, and vegetables
• Primary sources of fish mince are trimmings from manual or machine filleting operations
• Fish mince differs from surimi
  • Surimi has undergone leaching by water and the addition of sugars and polyphosphates
  • Fish mince does not have separation of sarcoplasmic proteins (albumin, myoglobin, and enzymes) and lipids
• Fish mince is less stable during frozen storage due to the presence of enzymes, haem pigments, and lipids

Surimi

• Japanese term for semi-processed frozen minced fish protein
• Manufactured from minced meat that has been leached by water and has additives (sugars, polyphosphates)
• In 1959, a team of Japanese scientists discovered a method to stabilize the muscle proteins of surimi during freezing
• Washing out water-soluble components and adding cryoprotectants (sugars, polyphosphates) extended the functional properties of surimi during freezing and storage
• Any fish can be used for surimi production
• White-fleshed marine fish are preferred for surimi manufacture (Alaska pollock, blue whiting)
• Restrictions on harvesting these temperate species are leading to the use of tropical trawl fishes

Surimi Processing Stages

• De-watering or Dehydration: Water is removed after leaching or washing
  • Water content should be 85% by weight
  • Methods include screw press, hydraulic press, centrifuge, or cheese cloth for small-scale operations
• Straining: This step removes scales, connective tissues, and small bones
  • A strainer with a cooling system is ideal
• Mixing: Meat is mixed with additives (sugar, polyphosphates) using a mixer, grinder, or silent cutter
  • Sugar should be 3-5% and polyphosphates should not exceed 0.3%
• Freezing: Mixed surimi is packed in polyethylene bags and quickly frozen in a contact or air blast freezer at -30°C

Surimi Quality Assessment

• Primarily based on gel strength and color
• Factors influencing quality are fish species, freshness, processing method, control, moisture content, freezing and storage temperatures, handling, and distribution conditions.
• Gel strength is measured objectively by rheometer or tensiometer and subjectively through sensory evaluation, folding, and teeth-cutting tests
• Surimi whiteness (required for fish balls and cakes) is measured using a whiteness meter
• Good quality surimi can absorb 30% or more of its weight in water
  • Produces cooked products with acceptable firmness, a springy, gel-like texture

Surimi Manufacturing Products

• Minced fish and/or surimi can be utilized in imitation products (crab legs, scampi, shrimp dumplings) or traditional foods (fish/shrimp/squid balls, nuggets, sausages, burgers).
• Minced fish products are classified as intermediate moisture food (IMF)
• Shelf life ranges from three days at room temperature to six months when vacuum packed
• Exports require freezing for longer shelf life

Fish Balls

• Popular food in the Philippines sold in markets and parks