Understanding Carbohydrates

Carbohydrates

• Large group of organic compounds in foods and living tissues
• Includes sugars, starch, and cellulose
• Contain hydrogen and oxygen in a 2:1 ratio, similar to water
• Primary function is to release energy in the animal body
• Chemically defined as polyhydroxy aldehydes or ketones, their derivatives, or polymers
• Considered an essential nutrient

Forms of Carbohydrates

• Sugars (fructose, glucose, lactose)
• Starches (starchy vegetables, grains, rice, breads, cereals)
• The body turns most carbohydrates into glucose, which is then absorbed into the bloodstream
• Saccharides relate to sugar and sweetness
• Mono, Di, Oligo carbohydrate groups
• Poly-Homo and Hetero carbohydrate groups

Key Examples

• Glucose
• Glycogen
• Lactose
• Fructose
• Mannose
• Galactose
• Cellulose
• D and L sugars
• Aldoses and ketoses
• Pentoses and hexoses
• Reducing and Non-reducing Sugars

Reducing Sugars

• Able to act as reducing agents
• Their functional groups change due to oxidation
• Forms carboxylic acid with Benedict’s solution
• React with other food components, changing color, flavor, and nutritive value in Maillard browning
• Include aldoses and ketoses with free functional groups
• Examples Glucose, Fructose, Glyceraldehyde, Lactose, Arabinose, Maltose

Benedict's Test

• Benedict's reagent/solution is a chemical reagent and complex mixture of sodium carbonate, sodium citrate, and copper(II) sulfate pentahydrate,
• It detects reducing sugars, and can replace Fehling's solution
• A positive reaction shows a color change from clear blue to brick-red with precipitate

Benedict's Test Procedure

• Dissolve a food sample in boiling water
• Add a small amount of Benedict's reagent and let the solution cool
• Color changes occur within 4-10 minutes
• A blue colorChange indicates no glucose
• High glucose amounts lead to color progression from green to yellow, orange, red, and dark red or brown

Fehling's Test

• Uses two reagents: a clear blue solution of copper sulphate and a colorless solution of sodium tartrate
• To perform the test, dilute the solution in water and warm until dissolved
• Add Fehling's solution while stirring
• Reducing sugars lead to a color change forming a rust or red precipitate
• If there are no reducing sugars the solution will remain blue or green

Practical Application of Reducing Sugar Tests

• Tests like Benedict’s and Fehling’s determine the presence of sugars in urine
• Positive result can indicate diabetes mellitus

Non-Reducing Sugars

• Lack a free functional group
• Example: Sucrose

Functions of Carbohydrates

• Main source of energy
• Role in fat metabolism
• Prevent ketosis
• Support digestive system function
• Fibers reduce blood cholesterol levels
• Prevent protein from being burned for energy, supporting construction and repair
• Supply energy to the central nervous system
• Come in various forms, including sugar, glucose, starch, and fibre

Dietary Sources of Carbohydrates

• Fructose: Fruits
• Galactose: Dairy products
• Lactose: Milk and dairy products
• Maltose: Cereal, beer, potatoes, processed cheese, pasta
• Sucrose: Sugar and honey (with trace vitamins and minerals too)

Healthy Food Sources of Carbohydrates

• Corn
• Potatoes
• Milk Products
• Fresh Fruits
• Vegetables

Unhealthy Food Sources of Carbohydrates

• White bread
• Artificial sugar
• Pastries
• Soda
• Highly processed foods

Importance of Carbohydrates

• Aid metabolism and provide glucose for energy
• Plant cells use cellulose (a disaccharide)
• Cellulose is a component of paper, textiles, and wood
• Photosynthesis uses sunlight and carbon dioxide to produce glucose, which stores energy in plants, and releases oxygen

Roles of Carbohydrates

• Primary energy source through glucose units
• Glycogen, a complex carbohydrate stored in animal cells, breaks down into glucose with stress and muscle exercise
• Chitin, a complex carbohydrate makes up arthropods’ exoskeletons
• Fuel brain, heart, kidneys, and the central nervous system
• Converted to glucose for energy
• Stores excess carbohydrates as glycogen in liver cells

Regulating Blood Sugar

• Insulin is made by the pancreas
• It lowers blood sugar and stores it as fat in the liver and muscles

Carbohydrates in Living Organisms

• Essential because they provide energy
• Ribose and deoxyribose sugars are key to genetic material structure

Additional roles of Carbohydrates

• Ribose sugar is a component of ATP (adenosine triphosphate)
• They turn carbon dioxide into organic substances that supply plants with energy
• Enhance seed germination and root elongation in soil
• Used to make blood sugar-controlling medications
• Complex oligosaccharides and oligonucleotides have anti-inflammatory properties aid in cancer treatment
• Nucleoside analogues derived from uncommon sugars are in antiviral medicines combatting HIV and HCV

Sugar Functions in Foods

• Influences sugar-water relationships
• Act as humectants by absorbing moisture
• Act as plasticizers
• Add texture
• React to heating
• Provide flavoring
• Able to form hydrogen bonds
• Act as sweeteners

Humectants

• Reduce water and microbial activity in food enhancing stability and maintaining texture
• Include salt and sugar
• Sorbitol (E420): Commonly used sugar alcohol
• Mannitol (E421)
• Glycerol (E422)
• Propylene glycol (E1520)

Plasticizers

• Substances added to make materials softer and more flexible
• Increase plasticity and decrease viscosity
• Examples: di-n-butyl phthalate (DnBP) and di (2-ethylhexyl) phthalate (DEHP)

Food Texturing Agents

• Additives, used to change texture
• Added in regulated quantities to improve texture
• Change the mouthfeel and food appearance

Examples of Texturing Agents

• Cellulose derivatives
• Gums
• Pectins
• Gelatins
• Algae extract
• Milk Proteins
• Starch
• Inulin
• Dextrose
• Used to disperse flavors and oils

Applications of Texturing Agents

• Dairy products and ice creams
• Confectionery and chocolate
• Jams, layers, and fillings
• Bakery and biscuits
• Snacks and meat products
• Ready-to-eat foods and pet food
• Sauces, dressings, and soups
• Solid fatty substances and beverages

Food Texturizing Agents: Types and Functionalities

• Acacia Gum: Reduces liquid surface tension and acts as an emulsifier
• Gelatin: Water-soluble, widely used as a gelling agent
• Pectin: Functions as a dietary fiber
• Starch: Acts as a stabilizer
• Xanthan Gum: Prevents oil separation and increases liquid viscosity

Candies

• Formed to be sucked or licked
• Range of flavors and types

Types of Candy

• Caramels: Made by cooking sugar and water
• Chocolate
• Gummies
• Hard Candies
• Licorice
• Lollipops and Sours
• Chewing Gums
• Cotton Candy

Candy Texture

• Ranges from soft and chewy to hard and brittle
• Candy creation involves dissolving sugar in liquid
• Ingredients, sugar concentrate, sugar crystal size, aeration, color, and the type of sugar all affect type

Jelly Candies

• Gumdrops and gummies: Stabilizers like starch, pectin, or gelatin are used

Caramel

• Caramel squares, Coffee Rio, Long Boys, Squirrel nut caramels, Caramel Crunch, Caramel Creams, Jelly Belly Caramel Corn, Vanilla Caramel are types of caramels
• Made by cooking sugar and water

Chocolate

• Hershey, Bar-Hershey, Milk Chocolate, Twix Mars, Snickers, Milk Duds, Milky Way, M&Ms, Kit Kat, Chocolate Covered Raisins, Chocolate Covered Cherries, Skittles, Baby Ruth, Almond Joy, Krackle are types of chocolate

Gummies

• Gelatin based and have chewy textures
• Range of shapes, colors, and flavors

Gummies: Varieties

• Gummi bears, Gummi worms, Gummi Cheries, Gummi cola bottles, Gummi fish, Gummi banana strawberry ring, Fraise Tagada

Hard Candies (Boiled Sweets)

• Sugary candies dissolve slowly in the mouth
• Candy Buttons, Candy canes, Jolly Rancher, Life Savers, Rock, Sweethearts (candy), PEZ are examples of hard candies

Licorice

• Semi-soft candy
• Often black licorice flavor or red strawberry/cherry flavor

Licorice: Types

• Red Vines, Snaps, Twizzler

Lollipops and Sours

• Types of lollipops Sugar Daddy, Chupa Chups
• Lilies and Lollipops are hard candies
• Warheads, Sour Patch Kids, Sour Punch, Toxic Waste are examples of sour candies

Chewing Gums

• Chewing gum, gum or bubblegum are other names
• Peach Blossoms, Abba-Zaba, Bit-O-Honey, Sky Bar, Boston Fruit Slices, Mall Cups, Wrigley's Chewing Gum, Fruit Stripe Gum are types/examples of chewing gums