CARBOHYDRATES:

WHAT ARE CARBOHYDRATES:

• Classifications of hydrated carbons → held together by covalent bonds

• Attracting water + dissolving in water

• Classified based of size + digestibility

  • Size: depends on how many sugar molecules are hooked together

    • Saccharide = carbohydrate

    • Monosaccharide: 1 sugar unit

    • Disaccharide: 2 sugar units

    • Polysaccharide

  • Digestibility: sugars, starches, fibers

• Cx(H2O)y

  • carbon

  • water

TYPES:

• Monosaccharides: Glucose and Fructose

  • 1 sugar unit

  • All monosaccharides differ in properties

    • EX: sweetness + solubility in water

  • Glucose: what food converts to for cells to use as energy (not sweet)

  • Fructose: what makes sweet (sweetest sugar)

• Disaccharides: Sucrose and Lactose

  • 2 sugar units → covalent bond

    • Bond = broken during digestion (use monosaccharides for energy)

  • Sucrose = glucose + fructose → less sweet than fructose

    • Table sugar, granulated sugar, caster sugar, etc.

    • Standard for sweetness 

    • Relative sweetness index value = 100

  • Lactose = glucose + galactose → can digest separately but as lactose its harder 

    • Sugar only found in milk

    • 40% of energy during nursing

    • Less sweet + soluble than sucrose

    • Lactose content of milks

      • Human: 7%+

      • Bovine and goat: 4.5-4.8%

    • Lactose intolerance → not an allergy

      • Not enough enzymes (lactase or B-galactosidase)produced to break the bond between glucose and galactose to digest

• Polysaccharides

  • Many sugar units linked together

  • Can be classified based on digestibility

    • Digestible: starches

      • Primary source of energy

      • Glucose units linked together

      • (Storage form of glucose for energy in plants)

      • Glycogen

    • Non-digestible: fibers (e.g. cellulose)

      • No energy intake

      • Glucose units linked together (not digestible) 

      • (structure in plants) → provides fiber for humans

    • Humans guest monosaccharides

      • Bonds are alpha or beta between sugar units (3D shape)

      • Human enzymes = only break down alpha bonds

        • Fibers = beta bonds

        • Lactose = beta bonds

FUNCTIONS IN FOODS:

• Sweeteners

  • Sucrose, fructose, maltose, etc. = nutritive sweeteners

  • Commonly used:

    • High fructose corn syrup

      • 55% fructose

      • 45% glucose

    • Sucrose

      • 50% fructose

      • 50% glucose

    • Invert sugar

    • Agave

      • 90% fructose

• Thickeners

  • Increase viscosity

    • Attracts + holds water

    • Some carbs are better than others at thickening

    • Flour = used to make a roux for gravy + sauces

    • Cornstarch → pastry cream

    • Stabilizers → xanthan gum or carrageenan

• Water binding

  • Carbs attract water + bonds easily with it

  • Water activity = measures the free water in food system

  • Carbs + water = no longer free water (can’t react with anything else)

    • Microbes = cant use water → less spoilage (preservative)

    • Water = doesn't freeze → softer when frozen

    • Higher water activity = shorter shelf life of food

    • More carbs = lower water activity = longer shelf life of food

• Contributes to browning

  • Caramelization

  • Maillard reaction