Unformatted text preview:

Seafood CompositionReasons for studying seafood compositionSlide Number 3Fish and shellfish as foodFish and shellfish as foodWhat is in fish muscle?Major components of seafoods WaterWaterCrude ProteinLipidsDark vs. White MuscleDark vs. White MuscleLipidsLipidsLipids - Fatty AcidsWhy are we interested in marine lipids?Importance of lipids in human nutritionCalories in Fat, Protein and CarbohydratesFatty acids ‘omega’ nomenclature: Carboxylic acidsStructure of acylglycerols (‘glycerols’)Calories in Fat, Protein and CarbohydratesThe w-6 and w-3 essential fatty acids familiesSlide Number 24Fats: Terrestrial vs. marine animalsFats: Terrestrial vs. marine animalsGood fat versus bad fatGood fat versus bad fatWhy omega-3 fatty acids are good for you?Why omega-3 fatty acids are good for you?Why omega-3 fatty acids are good for you?The ‘goodies’ in fish oils (fish lipids)Increasing fish oil consumptionThe fats in plant oils versus eulachon oil (type of fish oil)The lipids in some fish oilsOmega-3 intake American Heart AssociationSlide Number 37Essential vitamins in fish lipidsMinor Components of SeafoodMinor Components of SeafoodMinor Components of SeafoodSlide Number 42Seafood CompositionReasons for studying seafood composition To evaluate quality of fish and shellfish To determine nutritional attributes of fish and shellfish products To predict shelf life and ensure safety of processed fish and shellfish To develop processing methods for underutilized fish and shellfish To determine the important components affecting sensory attributes (flavor, odor and appearance)New food pyramid - USDAFish and shellfish as foodImportant things to know:Different from other animal proteins (primarily in muscle structure)Specific texture attributes (muscle texture)Limited shelf life (fish and shellfish spoil v. fast)Hundreds of fish and shellfish (to a lesser extent) species with different characteristics and nutritional benefitsFish and shellfish as foodImportant things to know:The fat in fish can be very high in omega-3 fatty acids (e.g. Pacific salmon = sockeye, chinook, coho, chum, and pink)Consumption Related to Prevention of Coronary Heart DiseasesSeafood has balanced amino acids make up and high protein content (healthy + nutritious)Shellfish tends to have high sterol levels, mainly cholesterol (e.g. shrimp)What is in fish muscle?Water and fat usually combine for 80% of the total composition of fish muscleWater and fat are interchangeable, that is, higher fat content lower water content and vice-versaProteins are the building blocks of living organismsFats (lipids) are the primary energy source for living organismsFats in terrestrial animals are VERY DIFFERENT from the fats found in marine animalsMajor components of seafoods The three major components of fish and shellfish are: Water Protein Lipids (fat) These three types of compounds make up as much as 95% of the total gross composition of fish and shellfish Average composition of fish muscleWater ~ 75%Protein ~ 15%Lipids (fat) ~ 5%Ash (minerals) ~ 5%Water Muscles contain 50% to 85% water, depending on species and condition Plays important roles: solvent for organic and inorganic materials reaction media for enzymes (perfect environment for enzymes to ‘do their work’) hydration of proteins (texture) Water binds with many of the proteins Water also influences proteins and lipids in forming ordered structuresWater Free water: is lost during freezing/thawing, muscle storage and handling Bound water: is not easily lost (~4-5% of the water in a muscle food) Water is critical to:processing characteristicstexturenutritive valuesensory qualityshelf lifeCrude Protein Crude protein refers to the total of nitrogen containing compounds in a sample. This includes proteins, enzymes, amino acids (e.g. lysine), nucleic acids (DNA), and nucleotides (e.g. ATP). Muscle proteins are of three classes: Water soluble proteins: found in abundance in the extra cellular fluid (between cells). Make up ~ 30% of total protein in fish muscle Salt soluble proteins: make up the "flesh" and are ~ 40-60% of the total protein in fish muscle (muscle cells) Collagen: make up 3% of total protein in fish muscle (connective tissue – ‘cement’, ‘glues’ muscle cells together)Lipids Lipid content in fish muscle is often times used to classify fish from ‘lean’ to ‘fatty’ Classification of seafood regarding its lipid content (Ackman,1990):Lean (<2% fat) - cod, haddock, shellfishLow fat (2-4% fat) - sole, halibut, flounderMedium fat (4-8% fat) -salmonHigh fat (>8% fat) - herring, mackerelDark vs. White Muscle Distribution and amounts of dark muscle are different among fish speciesSections through the bodies of several fish showing depth of dark muscle. (a) Herring; (b) Mackerel; (c) Tuna; (d) Haddock; (e) Cod; (f) Whiting. Source: Love, 1988Dark vs. White Muscle Fat content is markedly different between dark and white muscle Dark muscle contains: higher levels of myoglobin (hemoglobin in blood has iron and it promotes oxidation) than white muscle More enzymes present than in white muscle More fat than white muscle Combination of three factors listed above makes dark muscle loose quality faster then white muscle Removal of dark muscle is advisable during filleting (whenever possible) to reduce lipid oxidation and consequently development of off flavorsLipids Lipid content of fish muscle refers to the total amount of the following compounds:Phospholipids – important constituents of cell membranes (STRUCTURAL LIPIDS)E.g. Lecithinemulsifying agent used in the food industry (e.g. ice cream)Sterols – in fish mainly in the form of cholesterol; however, in mollusks and shellfish a wide variety of ‘sterols’ are present (cholesterol is related to proper growth and overall health)LipidsTriglycerides (TAG) - main source of energy in fish - FAT TAG are mainly stored in the liver of fish classified as leanFatty fish have TAG reserves mainly in their muscle and belly flap areaWax esters – used for buoyancy and found in large quantities in deep water fish; present in fish scales (waxes)E.g. Bee wax is composed of wax estersLipids - Fatty Acids Triglycerides (TAG) are composted of fatty acids Fatty acids are carboxylic acids E.g. Acetic acid is the


View Full Document

UAF FSN 261 - Seafood Composition

Download Seafood Composition
Our administrator received your request to download this document. We will send you the file to your email shortly.
Loading Unlocking...
Login

Join to view Seafood Composition and access 3M+ class-specific study document.

or
We will never post anything without your permission.
Don't have an account?
Sign Up

Join to view Seafood Composition 2 2 and access 3M+ class-specific study document.

or

By creating an account you agree to our Privacy Policy and Terms Of Use

Already a member?