Chap 5: Food Chemistry Flashcards
Food Chemistry
encompasses the composition and properties of food components and the chemical changes they undergo during handling, processing, and storage
Chemical Bonds
- Holds atoms and molecules together
- Requires energy
- Only electrons involved
Types of Bonds
- Covalent
- Ionic
- Hydrogen
Covalent Bonds
- Sharing one or more pairs of electrons
(Fats, proteins, and carbohydrates incorporate covalently bonded atoms to form backbones of food molecules)
Ionic Bonds
- Transfer of electrons
Hydrogen (Bond)
- Type of covalent bond
- Unequal sharing of electron
- Compounds containing oxygen, nitrogen bonded to hydrogen
Composition vs Decomposition
Composition - two or more substances combined to form a product A + B = AB
Sugars/Amino Acids —-> Polysaccharides/Proteins
Decomposition - One substance breaking down to form two or more products AB = A+B
Polysaccharides —-> Sugar
Enzymes
- Biological Catalysts
- Speeds up reactions
- Lowers activation energy
Desirable
Fermentation
Pickles, Tea, Yogurt
Oxidation
addition of oxygen or removal of hydrogen
Reduction
losing oxygen or gaining of hydrogen
Browning of fruits and vegetables (catalyst)
Polyphenol Oxidase
Browning of fruits and vegetables (melanin)
Oxidizes Polyphenols
Properties of Water
- Acts at a dilutant and carrier of hydrophilic substances
- Fat replacer
- Dispersing/solvent action
- Medium for heat transfer
- Plasticizer
Dipolar
Hydrogens share electron pair with oxygen
Boiling and Freezing Point
BP: 100 C & 212 F
FP: 0 C & 32 F