COMPLEX CARBOHYDRATES: STARCHES, CELLULOSE, GUMS AND PECTINS

FOODS RICH IN CARBOHYDRATES SOME CARBOHYDRATES ARE SIMPLE CARBOHYDRATES MANY ARE COMPLEX CARBOHYDRATES CALLED POLYSACCHARIDES BECAUSE THEY ARE MADE UP OF MANY SUGAR UNITS (SACCAHARIDES) POYSACCHARIDES ARE ALSO CALLED MACROMOLECULES BECAUSE THEY CONTAINS HUNDREDS OR THOUSANDS OF ATOMS EACH

TYPES OF COMPLEX CARBOHYDRATES STARCHES CELLULOSE GUMS PECTINS

STARCHES MOST ABUBDANT IN THE U.S. DIET ARE MADE UP OF MANY SUGAR UNITS LINKED IN CHAINS CALLED POLYMERS COMPOSED OF THE SUGAR GLUCOSE. HAS TWO BASIC STRUCTURES AMYLOSE – UNITS ARE LINKED IN A LINE (LINEAR) AMYLOPECTIN – UNITS ARE BRANCHED

STARCHES CONTINUED MOST ARE A MIXTURE OF AMYLOSE AND AMYLOPECTIN STARCHES COMPOSED MAINLY OF AMYLOPECTIN ARE CALLED WAXY STARCHES PLANTS PRODUCE STARCH IN PACKETS CALLED GRANULES THAT ARE NOT SOLUBLE IN COLD WATER GRANULES ARE A MIXTURES OF AMYLOSE AND AMYLOPECTIN THE RATIO DETERMINES HOW STARCHES PERFORM IN FOOD MIXTURES

SOURCES OF STARCH WHEAT FLOUR RICE CORN POTATOES OATS GRAIN OR SEED BAKED GOODS PASTA RICE CORN POTATOES OATS GRAIN OR SEED

CELLULOSE A POLYSACCHARIDE MADE FROM LARGE AMOUNTS OF BETA – D GLUCOSE SOME ANIMALS AND INSECTS CAN DIGEST BUT HUMANS CANNOT KNOW AS FIBER IN DIET FORMS THE RIGID STRUCTURE IN PLANTS (STRINGS IN CELERY ND MEMBRANES SURROUNDING CORN KERNELS

CARBOHYDRATE GUMS NOT GENERALLY AVAILABLE AT THE GROCERY STORE GUMS ARE POLYSACCHARIDES THAT ARE SOLUBLE IN WATER AND EXTRACTED FROM PLANTS USED TO THICKEN AND STABILIZE MIXTURES AND TRAP COLOR AND FLAVOR MOST COMMON IS GUM ARABIC SURROUNDS FLAVOR PARTICLES, PROTECTING THEM FROM MOISTURE, ABSORPORBTION, EVAPORATION, OR CHEMICAL OXIDATION COMMONLY USED IN SALAD DRESSINGS AND GUMMY CANDIES

PECTIN FOUND IN PLANT CELLS MADE OF CHEMICAL DERIVATIVES OF SUGAR CALLED SUGAR ACIDS NATURALLY OCCURS IN FRUITS PRODUCES A STRONG GEL REMAINS STABLE TO 1000 C (2120 F) CREATES A THICKENING STRUCTURE USED IN JAMS AND JELLIES

FUNCTION OF STARCH IN FOOD PREPARATION PROVIDES STRUCTURE RETAINS SHAPES RESPONSIBLE FOR TEXTURE BINDS HOLDS PRODUCTS TOGETHER STABILIZES TO PREVENT SETTLING THICKENS (GELATINIZATION) MOLECULES TAKE UP WATER HYDROGEN BONDS FORM BETWEEN STARCHES AND WATER

STRUCTURE MANY BONDS BETWEEN STARCH AND WATER MOLECULES CAN FORM STARCH MOLECULES ARE LARGE SPACES BETWEEN THEIR SUGAR UNITS TRAPS OR HOLDS WATER MOLECULES THE MORE WATER THEY HOLD. THE THICKER THE MIXTURE HEAT STRETCHES THE MOLECULES AND ALLOWS THEM TO HOLD MORE WATER

THICKENING POWER OF COMPEX CARBOHYDRATES TOO MUCH HEAT WILL CAUSE STARCH MOLECULES TO BREAK DOWN AND LOSE THICKENING ABILITY AND STABILITY THE PRESENCE OF SALT OR SUGAR ALSO AFFECTS STARCH’S THICKENING ABILITY BECAUSE THEY ARE ALSO POLAR MOLECULES THAT WILL BOND WITH THE WATER GUMS AND PECTINS ARE ALSO USED FOR THICKENING FOOD PRODUCTS

WHICH STARCH SOURCE IS BEST? IT DEPENDS ON WHAT TYPE OF FOOD PRODUCT OR STARCH-LIQUID MIXTURE IT WILL BE USED IN. REMEMBER THAT THE MOST IMPORTANT FACTOR IS USUALLY FLAVOR.

TYPES OF STARCH AND LIQUID MIXTURES SLURRIES – UNCOOKED MIXTURES OF WATER AND STARCH USED IN PROCESSING AND CHEMICAL ALTERATIONS. SOLS – THICKENING LIQUIDS THEY ARE POURABLE LIKE BATTER ARE COOKED SOLS LIKE GRAVY PASTES – THICKENING MIXTURES THAT HAVE VERY LITTLE FLOW AND CAN BE STIRRED INTO HOT LIQUIDS WITHOUT LUMPING GELS – MIXTURES THAT ARE RIGID AND ARE BOUND TOGETHER IN A 3-DIMENSIONAL NETWORK

PROPERTIES There are five properties that food scientists evaluate before selecting a starch for a starch-liquid mixture Retrogradation- the firming of a gel during cooling and standing Viscosity- the resistance of a mixture to flow Stability- the ability of a thickening mixture to remain constant over time and temperature changes Opacity- refers to how much an object blocks light Texture- the way a product feels to the fingers, tongue, teeth and palate

HOW DO YOU LIKE YOUR GRAVY? OPAQUE VS. TRANSLUCENT OPAQUE – USE FLOUR FOR THICKENING TRANSLUCENT – USE CORNSTARCH LUMPS OR NO LUMPS If you prefer no lumps GRAVY MIXES - may contain modified starches COLD WATER PASTE – stir starch and an equal amount of water until smooth before adding to hot mixture STARCH AND FAT – stir starch and an equal amount of heated fat until smooth and then slowly added liquid STARCH AND SUGAR – combine starch and sugar thoroughly then add to liquid Examples of the starch and fat mixture include the French, buerre manie and the Cajun roux.

NUTRITIONAL IMPACT DIGESTABLE STARCHES PROVIDE 4 CALORIES OF ENERGY PER GRAM MOST ABUNDANT AND ECONOMICAL SOURCE OF CALORIES PROVIDE OVER HALF OF DAILY CALORIES CARBS IN THE FORM OF GLUCOSE IS THE ONLY ENERGY SOURCE THE BRAIN CAN USE STARCHES AND SUGARS CAN BE EFFICIENTLY CHANGED TO ENERGY EXCESS CARBS ARE STORED AS GLYCOGEN GLYCOGEN IS STORED IN THE LIVER AND MUSCLES WHEN STORES ARE FULL THE EXCESS TURNS INTO FAT YOUR BODY DOES NOT NEED FAT TO PROPERLY USE STARCH. HOWEVER, CARBOHYDRATES MUST BE PRESENT TO COMBINE WITH FAT FRAGMENTS FOR YOUR BODY TO USE FAT FOR ENERGY. KETOSIS IS THE PROCESS OF BURNING FAT WITHOUT CARBOHYDRATES. THIS PROCESS PRODUCES KETONE BODIES. HIGH LEVELS OF KETONE BODIES OVER AN EXENDED TIME CAN CAUSE ADVERSE MEDICAL CONDITIONS.

NUTRITIONAL FACTS INDIGESTABLE FIBER CELLULOSE TERMS USED ON LABELS BRAN BULK HELPS YOU FILL FULL AIDS IN DIGESTION AND ELIMINATION SOURCES ARE COMPONENTS OF VEGTABLES, FRUITS, GRAINS AND ADDITIVES TO OTHER FOOD PRODUCTS TO SLOW DOWN STALING RATE

FUNCTION OF CARBS PROVIDES ENERGY FOR BODY FUNCTIONS PROVIDES BULK FOR DIGESTION PROCESSES DECREASES BILE ACIDS REABSORPTION LOWERS CHOLESTEROL LEVELS PROMOTES UTILIZATION OF FAT

CARBS ARE NOT THE ENEMY IN FACT, THEY ARE SO IMPORTANT THAT THEY REPRESENT THE LARGEST PORTION OF THE USDA’S MyPyramid SYMBOL