carbohydrates n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
CARBOHYDRATES PowerPoint Presentation
Download Presentation
CARBOHYDRATES

Loading in 2 Seconds...

play fullscreen
1 / 64

CARBOHYDRATES - PowerPoint PPT Presentation


  • 149 Views
  • Uploaded on

CARBOHYDRATES. SUGARS, STARCHES, PECTINS, AND OTHER CARBOHYDRATES. CHARACTERISTICS. Organic compounds Carbon, Hydrogen, Oxygen Simple or complex Source of energy or fiber Important food CHOs - Sugars, dextrins, starches, celluloses, hemicellulose, pectins, gums. FUNCTIONS. SWEETENERS

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'CARBOHYDRATES' - ernie


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
carbohydrates

CARBOHYDRATES

SUGARS, STARCHES, PECTINS, AND OTHER CARBOHYDRATES

characteristics
CHARACTERISTICS
  • Organic compounds
  • Carbon, Hydrogen, Oxygen
  • Simple or complex
  • Source of energy or fiber
  • Important food CHOs - Sugars, dextrins, starches, celluloses, hemicellulose, pectins, gums
functions
FUNCTIONS
  • SWEETENERS
  • THICKENERS
  • STABILIZERS
  • GELLING AGENTS
  • FAT REPLACERS
monosaccharides
MONOSACCHARIDES
  • SIMPLE SUGARS
  • MOST COMMON - 5 OR 6 CARBON
glucose
GLUCOSE
  • Dextrose
  • Naturally present in fruit
  • Basic unit for starches
  • Less sweet than fructose
  • Used in food industry because of water holding properties and ability to control crystals
  • Food for yeast
fructose
FRUCTOSE
  • Levulose
  • Part of sucrose
  • Sweetest of all sugars
  • In many fruits
  • Very soluble
  • Not easily crystallized
  • Glucose isomerase to change glucose to fructose
galactose
GALACTOSE
  • Part of lactose – milk sugar
  • Basic unit of pectic substances
  • Building block of many vegetable gums
disaccharides
DISACCHARIDES
  • Two monosaccharides
  • Glycosidic bonds-readily hydrolyzed by heat, acid, enzymes
sucrose
SUCROSE
  • Table sugar
  • From sugar cane or sugar beet
  • Glucose + fructose
  • Invert sugar important in controlling crystallization
  • Most common disaccharide
maltose
MALTOSE
  • Glucose + glucose
  • Product of starch breakdown
  • Corn syrup
  • Flavoring and coloring agent in beer, candies, shakes
lactose
LACTOSE
  • Glucose + galactose
  • Milk sugar
  • Extracted from solutions of whey
  • Not broken down or fermented by yeast
  • Does not react in batter leavened with baking soda or baking powder
  • Available for Maillard reaction so added to bakery products for browning
solubility
SOLUBILITY
  • Solution in foods
  • Varying degrees of solubility for monosaccharides and disaccahrides
  • As temperature increases  greater the amount of sugar that dissolves
  • Slow heating increases the solubility
  • As concentration increases  boiling point increases
  • Each gram molecular weight of sucrose increases boiling point 0.940F (0.520C)
  • Can use temperature to determine sucrose concentration
saturation
SATURATION
  • Unsaturated – small amount of sugar in water, can hold more sugar
  • Saturated – no more sugar can be dissolved
  • Supersaturated – holds more than what is usually soluble at a certain temperature
  • Supersaturation – heat to high temperature and cool slowly
crystallization
CRYSTALLIZATION
  • Cool supersaturated solution
  • Formation of closely packed molecules from the solidification of dispersed elements in a precise orderly structure
  • Arranged around a nuclei
  • Size of crystal depends on rate of formation of nuclei and rate of growth
  • Crystals form too soon  only a few  crystals too large, continue to grow, candy grainy
melting point heat decomposition
MELTING POINT/HEAT DECOMPOSITION
  • Apply dry heat  sugars melt to liquid state
  • Sucrose melts and forms liquid that turns brown
  • Carmelization – nonenzymatic browning, flavors food
  • Noncrystalline
hygroscopicity
HYGROSCOPICITY
  • Ability to absorb moisture
  • Responsible for lumpiness (sugar)
  • Decreases staling in bread
  • Gives stickiness for high moisture characteristics to foods
  • Fructose most hygroscopic
invert sugar
INVERT SUGAR
  • Acid hydrolysis of disaccharide sucrose
  • Heat increases hydrolysis
  • Glucose and fructose in equal amounts (equimolar)
  • Resists cyrstallization and retains moisture
  • Add cream of tartar, vinegar, molasses (acids)
  • Enzyme hydrolysis with invertase
types of sugars

TYPES OF SUGARS

CRYSTALLINE AND NON-CRYSTALLINE

granulated sugar
GRANULATED SUGAR
  • Crystalline – table sugar
  • Sugar cane or sugar beet
  • Affects texture of baked goods
  • Improves body and texture of ice cream
  • Fermented by yeast
  • Retards growth of microorganisms
  • Raw sugar banned by FDA
  • Turbinado –raw sugar separated in centrifuge, washed with steam
  • Retailed as fine or extra fine
powdered sugar
POWDERED SUGAR
  • Pulverized granulated sugar
  • Add cornstarch to prevent caking
  • X designates fineness
brown sugars
BROWN SUGARS
  • From cane sugar – late stages of refining
  • Crystals of sugar coated with molasses
  • Contains invert sugar
  • Sold in grades
  • More refined  lighter color, less flavor, lower grade – for baking – less flavor
  • Higher, darker grades more flavorful and suitable for cooking strong flavored foods
corn syrup
CORN SYRUP
  • Acid and high temperatures to hydrolyze corn starch
  • Varying degrees of sugars
  • High fructose corn syrup (HFCS) from high glucose corn syrup – use enzyme glucose isomerase
  • Significant use in food industry
molasses and sorghum
MOLASSES AND SORGHUM
  • By-product of sugar production from sugar cane
  • Mineral content varies
  • Bitterness increases as refinement continues – blackstrap molasses
  • Treacle – dark fluid left after sugar cane is processed
  • Sorghum – from cane sorghum, similar to molasses
maple syrup and honey
MAPLE SYRUP AND HONEY
  • Maple syrup from sap of mature maple trees
  • Water evaporated, organic acids cause flavor
  • Honey flavors according to flower nectars
  • USDA has standards for grades of honey
alternative sweeteners
ALTERNATIVE SWEETENERS
  • Non-nutritive – high intensity sweeteners
  • Approved saccharin, aspartame, acesulfame-K, sucralose, neotame
  • Except for sucralose not enough bulk to substitute in recipes
  • Cyclamates – banned
  • Sugar alcohols - polyols– improve bulk, mouthfeel, and texture
crystalline candies
CRYSTALLINE CANDIES
  • Generally soft
  • Smooth, creamy with tiny crystals that cannot be detected with the tongue
  • Fondant and fudge
  • Use interfering agent to prevent early crystallization
  • Must concentrate solution-test temperature to determine concentration
  • Complete solution of crystalline sugar
interfering agent
INTERFERING AGENT
  • Interfere with size or rate of crystal growth
  • Contribute to viscosity of syrup and elevate the boiling point
  • Examples – milk, butter, cream, eggs, chocolate, cocoa, proteins, fats, dextrins, invert sugar, corn syrup
non crystalline candies
NON-CRYSTALLINE CANDIES
  • Amorphous
  • No definite crystalline pattern
  • Cook to very high temperature
  • Adding large amounts of interfering agent
  • Combination of methods
  • Hard – brittles, high temperature, low moisture
  • Chewy – caramels, high interfering agent
  • Aerated – marshmallows, air trapped in protein foams and interfering agent
polysaccharides
POLYSACCHARIDES
  • Complex carbohydrate polymers
  • Properties depend on sugar units, glycosidic linkage and degree of branching
  • Starches, Pectins, Gums most important
  • Hydrocolloids – water loving colloidal substances
starch
STARCH
  • Plant polysaccharide - linked glucose monomers
  • GRANULES - formed in cells, grow by adding on layers
  • Long-chain glucose polymers
  • Insoluble in water
  • Form temporary suspension
sources
SOURCES
  • Characteristic of finished food depends on starch source
  • Seeds, roots and tubers
  • Cereal grains - wheat, corn, rice, oats
  • Roots and tubers - potatoes, arrowroot, cassava
structure

STRUCTURE

AMYLOSE AND AMYLOPECTIN

amylose
AMYLOSE
  • Straight chain or linear fraction
  • 1/4 of all starch
  • Thousands of glucose units
  • Forms thick gels-hold shape when molded, rigid
amylopectin
AMYLOPECTIN
  • Highly branched
  • 3/4 of starches
  • Thickens but does not gel
  • Proportion of amylose:amylopectin influences cooking qualities and keeping characteristics of finished food product
starch characteristics
STARCH CHARACTERISTICS
  • Ability to absorb water limited
  • In uncooked stage is insoluble in cold water - forms temporary suspension because polymer is too large
  • Doesn’t change boiling point or freezing point of liquid
  • Reversible
dry heat
DRY HEAT
  • Heating - increases uptake of water
  • Dextrinization
  • Color and flavor changes
  • Reduced thickening power
  • Nonenzymatic browning
  • Dry flour browned
moist heat
MOIST HEAT
  • Complete absorption as heat increases - permanent swelling, irreversible
  • Sol - as starch continues to come out of granules
  • Viscosity-thickness, thinness of liquid
  • Translucency increases during heating
gelatinization
GELATINIZATION
  • Sum of changes in first stages of moist heating of starch granules
  • Gelatinized granules = opaque, fragile, ordered structure disrupted
  • Temperature of gelatinization differs for each starch
  • Short chains of amylose come out of the granules
  • Irreversible changes
continued heating
CONTINUED HEATING
  • Gelatinization requires addition of heat
  • Cooking develops flavor
  • Pasting occurs
  • Granules swell
  • Granules of starch swell independently
paste characteristics
PASTE CHARACTERISTICS
  • Concentration of starch affects consistency
  • Clear thickened gel made from root starches or waxy versions of starches
  • Cloudy gels from cereal starches
slide48
ACID
  • Fragments (hydrolyzes) starch molecule = thinner hot paste and less firm product
  • Hydrolysis = less hydration of starch
  • Add acid after gelatinization and after starch has cooked
  • Applicable - lemon juice, vinegar, tomatoes
agitation
AGITATION
  • Over-stirring causes granules to burst, empty bound water = gel will thin
  • Creates more uniform mixture
other factors
OTHER FACTORS
  • FAT AND PROTEIN- coats (adsorbs) to surface of granule = delays hydration

Fat in pie crust to prevent clumping

  • SUGAR - competes for liquid = delays absorption by granule = thinner mixture

Elevates temperature for gelatinization

  • ENZYMES - hydrolyze starch molecules
time and temperature
TIME AND TEMPERATURE
  • Lengthen heating time = causes granules to rupture - thins product
  • More rapid heating = smoother paste
  • Bring to boil over direct heat
gelation
GELATION
  • Formation of a gel when gelatinized starch is cooled
  • Strong amylose bonds
  • Elastic solid
  • Retrogradation-reverting to crystalline state
  • Syneresis - water loss during retrogradation, “weeping”-as water evaporates dried out rubbery matrix of starch
  • Non-pourable, highly viscous
separating agents
SEPARATING AGENTS
  • DEFINED - ingredients or additives which physically separate starch granules during hydration, allowing maximum hydration
  • Prevents lump formation
  • FAT -ROUX- forms film around granule = each granule swells independently of others
  • COLD WATER- SLURRY-physically separates granules (hot water causes partial gelatinization)
  • SUGAR-LIAISON - physically separates
modified starches
MODIFIED STARCHES
  • Defined-starches which have been chemically altered to produce physical changes
  • Will improve stability, convenience, performance during food processing
  • Use acids or oxidizing agents
  • FDA-regulations governing modification
examples
EXAMPLES
  • PREGELATINIZED STARCH - gelatinized, dried, can reconstitute without heat (instant potatoes, hot cereal)
  • Acid-modified starch - treated with acid slurry, forms strong gel upon cooling
  • Cross-linked starches - acid resistant, resists rupture
  • Cold water-swelling - instant starch that remains intact
functions of modified starches
FUNCTIONS OF MODIFIED STARCHES
  • Increase acceptability of product flavor and consistency
  • Prevent retrogradation
  • Stabilizers in conjunction with emulsifiers
  • Improve freeze-thaw stability
  • Prolong shelf life of frozen food by preventing oxidation
waxy starches
WAXY STARCHES
  • Commonly used in pie fillings
  • Made from natural starches
  • Practically no amlyose
  • Thicken at lower temperature but no gelling
  • Less retrogradation
  • Barley, corn, rice, sorghum
high amlyose starches
HIGH AMLYOSE STARCHES
  • Genetic manipulation
  • Form films and bind other ingredients
pectins and gums
PECTINS AND GUMS
  • Polysaccharides
  • Plant tissue
  • Used as gelling agents, thickeners, stabilizers
pectic substances
PECTIC SUBSTANCES
  • Part of primary cell wall
  • Hold cells together, hold skin on fruit
  • Protopectin - immature fruits
  • Pectinic acid- mature fruit, includes pectins
  • Pectic acid - over ripe fruit
pectin
PECTIN
  • Dispersible in water
  • Forms a sol
  • Can be converted to a gel in the presence of water with addition of sugar or acid
  • Attraction to water is decreased
  • Pectin under skin of fruits melts with heat application (peel tomatoes, etc)
pectins
PECTINS
  • Commercially extracted from apple cores and skins; form white inner skin of citrus fruits
  • Boiling too long - depolymerization occurs, gel may not set
  • Boiling too short - insufficient invert sugar formed, sucrose may crystallize
slide63
GUMS
  • All are colloidal polymers (too large to dissolve)
  • All are very hydrophilic
  • All are thickeners in water dispersions
  • Galactose most common sugar
  • All are polysaccharides – EXCEPT for gelatin
  • Examples: Guar gum, gum arabic, carob bean gum, carageenan, agar, xanthan gum
slide64
USES
  • Thickening agents replacing starch
  • Stabilizers of emulsions
  • Maintain smooth texture of products like ice cream
  • All do not form gels