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WorksheetsApplied Food Science Revision
Total questions: 107
Worksheet time: 54mins
Which statement best describes why water is considered polar?
Water has no charges anywhere in the molecule
Hydrogen atoms carry full negative electric charges
Oxygen end has partial negative, hydrogen end partial positive
Electrons distribute evenly around all atoms
In food production, why does salt dissolve readily in water?
Salt has no interaction with water molecules
Salt is polar and attracted to water’s partial charges
Salt is non-polar like oil molecules
Salt dissolves only due to high temperature
Which pair correctly matches molecule type with water’s dissolving behavior?
Both polar and non-polar—dissolve equally
Neither polar nor non-polar—ever dissolves
Polar molecules—do not dissolve; Non-polar—dissolve easily
Polar molecules—tend to dissolve; Non-polar—do not dissolve
What feature of water allows it to act as a universal solvent in many food processes?
Its lack of any electrical properties
Its bent shape creating partial charges
Its ability to form metallic bonds
Its straight molecular shape without angles
A sauce separates when oil is added to water. Which reasoning best explains this outcome?
Water is non-polar and cannot mix with oil
Oil has stronger ionic bonds than water
Oil is non-polar and does not interact with water’s partial charges
Oil is polar and repels water’s charges
Which statement most directly connects water polarity to desired textures in cookery?
Polarity increases water’s viscosity to thicken foods
Polarity reduces water’s temperature, preventing texture changes
Polarity lets water dissolve polar ingredients, affecting structure
Polarity eliminates all charges, stabilizing textures
During candy making, sugar dissolves in water to form a syrup. Which concept explains this process?
Water dissolves only metals, not sugars
Sugar is non-polar and avoids water’s charges
Sugar breaks water’s covalent bonds completely
Water’s partial charges attract polar sugar molecules
Which statement best describes a true solution?
Homogeneous mixture with visible dispersed particles
Heterogeneous mixture with intermediate particles
Homogeneous mixture with dissolved solutes
Heterogeneous mixture with settling particles
Which mixture is most likely to show particles settling upon standing?
Solution with particles under 1 nm
Colloid with particles 1–1000 nm
Suspension with particles over 1000 nm
Solution with evenly spread molecules
In a colloid, why don’t dispersed particles settle out?
They are dissolved completely as solutes
They are heavier than the dispersion medium
They are not large like suspension particles
They are smaller than solution molecules
Match each mixture type to its typical particle size range.
Solution: <1 nm; Colloid: 1–1000 nm; Suspension: >1000 nm
Solution: variable; Colloid: dissolved; Suspension: settled
Solution: >1000 nm; Colloid: <1 nm; Suspension: 1–1000 nm
Solution: 1–1000 nm; Colloid: >1000 nm; Suspension: <1 nm
A mixture has evenly spread particles that are intermediate in size and do not settle. What is the best classification?
Solution with visible particles
Colloid in any dispersion medium
Suspension in water
Solution in a liquid solvent
Which statement best defines surface tension in liquids?
A measure of liquid density near the surface
A pressure increase caused by evaporation
A resistance of the surface to external force
A tendency of molecules to form ionic bonds
What primary intermolecular interaction strengthens cohesion in water?
Hydrogen bonding between water molecules
Ionic bonding among dissolved salts
Metallic bonding across the surface
Covalent bonding within single molecules
Why do water droplets tend to be spherical when forming on a surface?
Evaporation cools and contracts the water
Gravity compresses the liquid evenly
Surface tension minimizes surface area
Air pressure shapes droplets symmetrically
Which scenario best illustrates capillary action driven by surface tension?
Steam condensing on a cold window
Water rising in thin plant xylem tubes
Salt crystals forming from seawater
Ice floating on a lake in winter
At the water’s surface, why is there a net inward pull on molecules?
They bond only to neighbors beside and below
They bond equally in all directions
They form new bonds with the air above
They lose all cohesive forces at the surface
Some insects can walk on water primarily because
They reduce gravity through wing flapping
They are lighter than air around them
Their legs chemically repel liquid water
Their weight does not break surface tension
Which statement best describes how pressure affects water’s boiling point?
Lower pressure raises boiling temperature dramatically
Higher pressure raises boiling temperature moderately
Lower pressure makes boiling independent of temperature
Higher pressure lowers boiling temperature significantly
At roughly 2,000 meters above sea level, water typically boils near which temperature due to lower atmospheric pressure?
About 93°C under reduced pressure
About 110°C at high elevation
Exactly 100°C at any altitude
Below 80°C in all mountains
A pressure cooker shortens cooking time mainly because it
removes free water from ingredients
decreases heat transfer to the food
increases boiling point by raising pressure
reduces water activity dramatically
Which scenario would most likely increase the risk of microbial growth based on Aw?
Moderate Aw from entrapped water
High Aw with abundant free water
Very low Aw due to crystallized starch
Low Aw from bound water in jam
Water activity (Aw) primarily measures the amount of
vapour pressure at sea level only
free and entrapped water available
bound water unavailable to microbes
total moisture including all forms
Which type of water is NOT counted in Aw because it is inaccessible to microbes or vapour?
Bound water held by constituents
Entrapped water flowing when freed
Surface moisture on vegetables
Free water released by cutting
A fruit gel (high pectin) contains water immobilized in its structure. Which classification fits best, and what happens if the structure is broken?
Entrapped water; flows freely when released
Free water; stays unchanged when disturbed
Bound water; remains inaccessible after rupture
Bound water; instantly evaporates when cut
Choose the best explanation for why water boils at a lower temperature at high altitude.
More wind increases heat loss from pots
Lower humidity absorbs heat from water
Less atmospheric pressure reduces required energy
Colder air prevents bubbles from forming
Which statement best describes ionic bonding?
Atoms merge nuclei to become one particle
Electrons move freely without forming compounds
Ions are held together by opposite charge attraction
Atoms share electrons to fill valence shells
What happens to sodium chloride when it dissolves in water?
It forms Na2 and Cl2 neutral atoms
It releases protons to make acid
It splits into Na+ and Cl− moving ions
It becomes a covalent molecule NaCl
Covalent bonding primarily involves which process?
Electron transfer creating ions
Protons exchanging between nuclei
Opposite charges attracting
Electron sharing between atoms
Which pair of atoms most likely forms a covalent bond?
Potassium and bromine in KBr
Magnesium and oxygen in MgO
Oxygen and hydrogen in water
Sodium and chlorine in table salt
An atom becomes a cation when it does what?
Attracts anions through dipoles
Shares electrons equally in pairs
Loses electrons becoming positive
Gains electrons becoming negative
Why do ionic compounds form solid lattices at room temperature?
Shared electrons create flexible bonds
Opposite ions attract in strong arrays
Metal atoms stack with free electrons
Molecules align through weak forces
Which explanation fits the phrase “Sharing is caring” used for covalent bonds?
Electrons move independently in solutions
Ions with opposite charges attract strongly
Atoms share valence electrons to fill shells
Atoms donate electrons to other atoms
Which change would convert a neutral chlorine atom into an anion?
Sharing electrons with sodium
Releasing a proton from nucleus
Gaining one valence electron
Losing one valence electron
Which set lists the four core parts found in every amino acid?
Hydroxyl group, aldehyde group, nitrogen base
Carbonyl group, methyl group, sulfur, R group
Amino group, carboxyl group, phosphate, sugar
Central carbon, hydrogen, amino group, R group
What best describes the R group in amino acids?
Charged group always hydrophilic
Fixed group identical in all amino acids
Backbone forming peptide linkage
Variable side chain determining properties
During peptide bond formation, which two groups react directly?
Two R groups from adjacent residues
Amino of one and R group of another
Carboxyl of one and amino of another
Hydrogen from backbone and hydroxyl
Which statement about a dehydration reaction in peptide bond formation is correct?
Water is converted into hydroxide
Two water molecules are released
A molecule of water is absorbed
A molecule of water is released
An amino acid with a non-polar R group is most likely to be
Hydrophobic and water-hating
Hydrophilic and water-loving
Always basic and positively charged
Always acidic in solution
Which change would most likely alter a protein’s properties without breaking the backbone?
Eliminating the amino group from all residues
Deleting the carboxyl group from the backbone
Removing the central carbon from residues
Replacing an R group with a different side chain
You join three amino acids sequentially. How many peptide bonds form and how many water molecules are released?
Three bonds and three waters
One bond and one water
Two bonds and three waters
Two bonds and two waters
Which sequence correctly describes building a polypeptide chain?
Amino acids link by peptide bonds
R groups condense into nucleotides
Carboxyl groups form hydrogen bonds
Water adds to break peptide bonds
Which description best matches primary protein structure?
Linear order of amino acids with peptide bonds
Association of multiple polypeptide subunits
Local folding into helices and sheets structures
Overall 3-D shape of a single polypeptide
Which feature is characteristic of secondary protein structure?
Alpha-helix and beta-pleated sheet patterns
Specific sequence of amino acid residues
Binding between different protein subunits
Covalent disulfide linkages only
Tertiary structure is primarily determined by which interactions?
Peptide bond formation along the chain
Side chain interactions forming a 3-D fold
Subunit assembly into larger complexes
Hydrogen bonds in helix and sheet motifs
Quaternary protein structure refers to what organization?
Local helix or sheet within one chain
Single-chain 3-D folding conformation
Arrangement of more than one polypeptide
Exact amino acid sequence information
Which statement distinguishes an alpha-helix from a beta-pleated sheet?
Alpha-helix forms a coiled structure; beta-sheet forms aligned strands
Alpha-helix creates multi-subunit complexes; beta-sheet does not
Alpha-helix defines primary sequence; beta-sheet defines peptide bonds
Alpha-helix involves only covalent bonds; beta-sheet involves none
A protein with two identical polypeptide chains functioning together exemplifies which level?
Secondary structure forming sheets and helices
Quaternary structure involving subunit association
Tertiary structure of a single polypeptide
Primary structure listing amino acid sequence
If a mutation changes one amino acid in a polypeptide, which level is directly altered first?
Primary sequence of the polypeptide chain
Quaternary arrangement of multiple chains
Secondary motifs such as helices and sheets
Tertiary fold of the complete protein
Which statement best describes protein denaturation in foods?
Proteins gain more active sites and increased activity
Proteins dissolve completely into amino acids
Proteins undergo physical unfolding and loss of function
Proteins form stronger native bonds and harden
Which condition commonly causes proteins to denature during food processing?
Heat, acid, salt, alcohol, or agitation
Low light exposure in storage
Mild cooling below room temperature
Addition of water without mixing
Why is denaturation considered desirable when cooking eggs?
It prevents any structural change during heating
It increases yolk color intensity and shine
It unfolds proteins so they coagulate and firm
It keeps proteins soluble and runny in liquid
In cheese making, what role do acid or rennet enzymes play?
They pasteurize milk by killing microbes
They add flavor without changing proteins
They dissolve casein to make milk sweeter
They denature casein allowing curd formation
A baker wants bread with good structure and volume. Which process supports this outcome?
Keeping gluten fully native and flexible
Adding cold water to avoid protein changes
Denaturing gluten and egg proteins by heat
Preventing any agitation of the batter
What happens to enzyme activity when the enzyme protein is denatured?
It breaks down only lipids and not proteins
It gains new active sites and extra products
It no longer fits the substrate; reaction stops
It binds substrates more tightly and faster
Match each enzyme to its substrate and product.
Amylase → starch → simple sugars
Lactase → starch → glucose and fructose
Lactase → lactose → glucose and galactose
Protease → starch → amino acid fragments
A food technologist notices an enzyme-substrate complex fails to form. Which reasoning best explains this?
The enzyme is folded perfectly and highly specific
The products are already leaving the active site
The substrate concentration is exactly optimal
The enzyme is denatured and active site misshapen
Which statement best defines protein coagulation in foods?
A change in protein structure causing thickening
A cooling process that keeps proteins dissolved
A sugar reaction that browns the surface slowly
A moisture loss that dehydrates the whole food
When egg white turns from clear to solid during heating, which process is occurring?
Coagulation of egg proteins
Fermentation of albumen
Gelatinization of starch
Emulsification of lipids
Which condition most commonly triggers protein coagulation in foods like eggs and milk?
High sugar and salt addition
Cold storage with low humidity
Heat or acid causing denaturation
Extended fermentation with yeast
Gluten in dough develops most effectively under which set of conditions?
Salt dissolved, dough folded, air-dried
Water added, dough kneaded, kept warm
Dry flour sifted, dough rested, kept cold
Oil added, dough mixed lightly, chilled
Which pair are the main proteins that combine to form gluten?
Albumen and myosin
Prolamin and glutelin
Casein and whey
Glutenin and gliadin
Which factor inhibits gluten formation during dough preparation?
Presence of fat in the mixture
Warm environment during proofing
Adequate water for hydration
Prolonged kneading of dough
A baker wants a tender pastry with minimal gluten. Which modification best achieves this?
Add extra water to hydrate proteins
Keep dough warm to accelerate bonds
Increase fat to coat flour particles
Knead longer to align protein chains
Seitan is primarily made from which ingredient and is best described how?
Soy protein isolate; dairy-free cheese alternative
Vital wheat gluten; plant-based meat substitute
Brown rice gluten; high-fat meat replacement
Pea protein flour; fermented grain product
Compared with animal meat, what is a nutritional limitation of seitan?
Excess saturated fat from grain oils
High sugar formation during cooking
Low carbohydrate content in gluten
Limited amino acid profile due to gluten
Which description of gluten’s role in dough is most accurate?
Reduces moisture and prevents hydration entirely
Acts as a leavening gas that expands bubbles
Adds sweetness and increases browning reactions
Provides elasticity and helps hold dough together
Which classification describes monosaccharides within carbohydrates?
Polymers forming storage starch
Dimers forming complex fibers
Monomers forming simple sugars
Cross-linked proteins chains
Which set lists examples of disaccharides?
Sucrose maltose lactose
Glucose fructose ribose
Starch cellulose glycogen
Galactose glucose fructose
Which category includes starch, cellulose, and glycogen?
Disaccharides dimers
Polysaccharides polymers
Lipids triglycerides
Monosaccharides monomers
Identify the molecule type shown as a single ring labeled glucose in the diagram.
Monosaccharide single unit
Amino acid building block
Polysaccharide many units
Disaccharide two units
Monosaccharides in food science most relevant are which two?
Sucrose and lactose
Ribose and cellulose
Glucose and fructose
Starch and glycogen
All three—glucose, galactose, and fructose—share C6H12O6 but differ in arrangement. What term describes this relationship?
Isomers same formula
Isotopes extra neutrons
Enzymes protein catalysts
Ions charged atoms
A student claims fructose and glucose have identical properties because their formulas match. What is the best response?
They are disaccharides only
They are the same sugar
They differ as isomers
They become equal in water
Which statement correctly contrasts simple and complex carbohydrates in the diagrams?
Simple are single or double units
Complex are single units only
Simple are long branched chains
Complex are one-ring structures
Which statement best describes a reducing sugar in food chemistry?
Donates electrons to another molecule
Absorbs electrons from proteins
Forms water when heated strongly
Always occurs only in disaccharides
Which reaction requires amino acids and involves browning and aroma formation?
Simple hydrolysis
Fermentation process
Maillard reaction
Caramelisation only
Which carbohydrate is NOT a reducing sugar?
Lactose
Sucrose
Maltose
Glucose
What primarily causes browning when sucrose is heated without proteins present?
Gelatinisation
Maillard reaction
Oxidative rancidity
Caramelisation
Which statement about monosaccharides and disaccharides is accurate?
Only ketoses are reducing carbohydrates
Only sucrose is a reducing disaccharide
No disaccharides are reducing sugars
All monosaccharides are reducing sugars
Sugar alcohols are commonly called polyols and are used to replace which ingredient in foods and drinks?
Fat triglycerides
Dietary fiber cellulose
Table sugar sucrose
Protein casein
Which property most distinguishes sugar alcohols from regular sugar?
About half the calories
Higher melting point
Stronger sweetness always
Requires protein to react
Which scenario best explains why some "sugar free" products still taste sweet?
They contain sugar alcohol polyols
They rely solely on amino acids
They use only unsweet starches
They are sweet due to proteins
Which statement best describes sugar crystallisation during confectionery making?
Water is driven off forming thick syrup
Fats emulsify to create smooth texture
Proteins denature creating firm structure
Starch gels to trap water molecules
Which product most commonly relies on sugar crystallisation for its texture?
Shortcrust pastry cases
Yeast-leavened breads
Tablet and toffee sweets
Crème caramel dessert
What visible change signals sugar caramelisation when heated in a liquid or as a topping?
Turns brown due to heat
Separates into oil droplets
Forms opaque white crystals
Produces foamy air bubbles
Which kitchen outcome is a risk if sugar is caramelised for too long?
It will curdle dairy proteins
It will burn and taste bitter
It will ferment into alcohol
It will freeze and harden
During aeration, what role does sugar play when creamed with fat?
Raises gelatinisation temperature
Stabilises emulsions preventing separation
Absorbs moisture to reduce stickiness
Traps air making mixtures lighter
Which baked item most depends on aeration from sugar creamed with fat?
Pickled vegetables
Cakes and sponge batters
Roasted meats with glaze
Custard-based desserts
How does sugar contribute to colour in baked products?
Gives a golden brown surface
Bleaches pigments during baking
Creates bright red caramel hue
Prevents any browning reactions
Which combination correctly matches a functional property with a typical use?
Caramelisation—crème caramel
Aeration—jam preservation
Colour—bread fermentation
Crystallisation—meat tenderising
Which statement best describes aeration during the creaming of sugar and fat?
Air is added by melting fat gently
Fine powders prevent any air incorporation
Sugar crystals cut fat, trapping air bubbles
Fat dissolves sugar crystals completely
Why is caster sugar preferred over icing sugar for aeration in baking?
Icing sugar has more moisture content
Caster sugar crystals are finer and sharper
Caster sugar dissolves slower in water
Icing sugar contains added starch thickeners
During aeration, what role does fat play in the mixture?
Fat evaporates to lighten the batter
Fat reacts chemically with sugar
Fat surrounds and traps air bubbles
Fat expels air from the mixture
Artificial sweeteners often fail to aerate mixtures effectively because they are typically:
Amorphous gels with high viscosity
Highly hygroscopic solids
Large crystalline granules
Very fine powders lacking sharp edges
Starch gelatinisation requires the combined presence of:
Acid, light, and cold
Starch, moisture, and heat
Protein, enzymes, and salt
Sugar, fat, and pressure
What occurs between about 60°C and 71°C during starch gelatinisation?
Amylose chains fully crosslink
Paste sets into a permanent gel
Grains burst and form a sol
Water is absorbed by starch grains
Which sequence correctly depicts the later stages of gelatinisation?
Absorption stops, grains shrink, paste thins
Water evaporates, grains crystallise, fluid thins
Grains swell, rupture, sol forms, viscosity increases
Grains freeze, amylose leaches, paste clarifies
In food applications, gelatinisation is primarily used to:
Stabilise proteins in meat marinades
Aerate cakes and cookies
Thicken sauces, soups, and custards
Caramelise sugars in syrups
Which event initiates the caramelisation of sucrose during heating?
Melting of the sugar with foaming
Immediate formation of caramels
Rapid crystallisation on cooling
Addition of water to the mixture
During caramelisation, sucrose first breaks down into which two monosaccharides?
Glucose and fructose
Glucose and galactose
Ribose and glucose
Fructose and lactose
Which statement best describes the role of condensation in caramelisation?
Steam removes volatile flavours
Water condenses on cooler surfaces
Sugars absorb water and expand
Sugars lose water and react together
Which product group mainly contributes to the complex flavours formed during caramelisation?
Aromatic compounds from caramelins
Organic acids from fermentation
Proteins from Maillard browning
Mineral salts from inversion
Identify the correct sequence element found among the reactions in caramelisation.
Isomerization of aldoses to ketoses
Hydrogenation of double bonds
Oxidation producing carbon dioxide
Formation of crystalline lattices
What happens when sugar is dissolved in water, heated, and then cooled?
It decomposes into carbon dioxide
It reverts to a crystalline form
It remains a supersaturated liquid
It forms stable glassy amorphous solids
To achieve smoother fudge, what processing step is applied as the mixture cools?
Resting to allow large crystals
Adding salt to halt crystallisation
Filtering to remove seed crystals
Beating to create smaller crystals
Which syrup stage most closely matches 118–120°C and about 87% sugar concentration?
Thread stage for syrups
Hard crack stage for brittles
Soft ball stage for fudge
Firm ball stage for caramels
