Food Science Quiz 12
What this quiz covers
Before any food can be judged safe, somebody has to measure it — and the measurement is only as good as the person reading the instrument. This quiz is a tour of the food laboratory bench: the refractometer that reads total soluble solids in a drop of juice, the pycnometer that pins down specific gravity, the sensory tests that turn human opinion into data, and the mill that grinds grain with compression and shear. Lab literacy is what separates a technician who follows a method from one who understands it, and employers notice the difference fast.
Twenty questions cover innate immunity, PPO-driven browning in cut fruit, salt as a Class 1 preservative, PET for carbonated drinks, rice kernel weight, casein as a laminate adhesive, where probiotics cannot help, why proteins are amphoteric, niacin and pellagra, liquid nitrogen as a cryogen, the ranking test for intensity, specific heat, what temperature and pH do to enzymes, the Celsius–Fahrenheit conversion, hydrogen sulfide blackening pickles, roller mills, and ethylene’s role in climacteric fruit.
Instruments, ingredients, and the odd-one-out habit
Many questions here are built as odd-one-out puzzles: which item does not belong, which nutrient eggs lack, which gas ripens climacteric fruit. That format rewards crisp definitions — know exactly what a refractometer measures and you will never confuse it with a penetrometer again. The ingredient questions work the same way: PPO causes browning, proteins carry both charges, ethylene ripens climacteric fruit. Definitions first, answers follow.
How to use this quiz
You get 20 seconds per question and one attempt at each answer. When you miss an instrument question, learn what the instrument physically does — a refractometer bends light, a pycnometer weighs a known volume — because the principle is what sticks. For the fact questions, make pairs: niacin–pellagra, ethylene–climacteric, PPO–browning. Retake the quiz in a few days; the pairs that survive are learned, and the ones that don’t are your study list.
Answer explanations
Worked through the quiz? Here is why each correct answer is correct — the concept behind it, in plain terms.
- The immunity with which a person is born is
Correct answer: innate — Innate immunity is present at birth — skin, phagocytes, complement — while acquired (adaptive) immunity is learned through exposure or vaccination. - TSS of fruits is measured by
Correct answer: refractometer — Total soluble solids in fruit are read on a refractometer as °Brix; penetrometers test firmness and hydrometers density. - Which enzyme is responsible for browning of cut fruits and vegetables
Correct answer: PPO — Polyphenol oxidase (PPO) oxidizes phenols to brown melanins the moment cut surfaces meet air — the enzyme behind browning in apples and potatoes. - Which of following is not a preservation technique
Correct answer: micro filtration — The marked answer looks wrong: microfiltration genuinely is a preservation technique — it cold-sterilizes milk and juices by physically removing bacteria — while “packaging” alone preserves nothing without a barrier treatment. Flagging this key for review. - Which one is class 1 preservative
Correct answer: salt — Class 1 preservatives are the traditional ones — salt, sugar, vinegar — used since antiquity, as opposed to synthetic Class 2 preservatives like sorbates and benzoates. - Carbonated drinks and water is packaged in
Correct answer: PET — Carbonated drinks need a bottle that holds pressure without leaking CO2: PET’s strength and gas barrier make it the standard. - Kernel weight of rice
Correct answer: 40-50mg — The question bank gives a rice kernel as 40–50 mg; treat this as the bank’s figure — typical thousand-kernel weights for rice run lower, so this value is worth double-checking against the source text. - Which of the following is used as an adhesive in laminates
Correct answer: casein — Casein glues bond paper and foil plies in laminates — a milk-protein adhesive from long before synthetics took over. - Which of the following cannot be prevented by consumption of probiotics
Correct answer: respiratory disorders — Probiotic evidence is strongest for gut and urinary-tract conditions; respiratory disorders sit outside that evidence base, making it the odd one out. - Which of the following is amphoteric in nature
Correct answer: proteins — Proteins carry both acidic (carboxyl) and basic (amino) groups, so they can act as acids or bases depending on pH — the definition of amphoteric. - Deficiency of niacin can cause
Correct answer: Pellagra — Niacin deficiency causes pellagra — the 4 D’s: dermatitis, diarrhea, dementia, and death. Beri-beri is thiamine, scurvy vitamin C, rickets vitamin D. - Which of the following is an example of cryogenic agent
Correct answer: liquid N2 — Liquid nitrogen (−196°C) is the standard cryogenic agent for freezing tunnels and lab work; liquid hydrogen is a rocket fuel, not a food refrigerant. - Which of the following contains antimicrobial and anti-inflammatory factors
Correct answer: both — Spices and condiments both carry antimicrobial and anti-inflammatory compounds — allicin in garlic, curcumin in turmeric, eugenol in clove. - Which of the following differentiates a sample based on its intensity
Correct answer: Ranking Test — In a ranking test, panelists order samples by intensity of an attribute — the test built specifically for intensity differences. - Heat required to raise the temperature of 1g of substance by 1°C is called
Correct answer: specific heat — The heat needed to raise 1 g by 1°C is the specific heat capacity — water’s famously high value (4.18 J/g°C) is why foods heat slowly. - The enzymatic reactions are most affected by
Correct answer: Both — Enzyme reaction rates hinge on temperature (too hot denatures the protein) and pH (too far from optimum ionizes the active site) — both at once. - 10°C is equivalent to _______ °F
Correct answer: 50 — °F = (°C × 9/5) + 32, so 10°C = 50°F exactly. - Blackening of pickle occurs due to formation of
Correct answer: hydrogen sulfide — H2S from sulfur compounds reacts with iron from lids or water to form black iron sulfide — the classic pickle-blackening reaction. - Which of the following mill uses compressive and shearing forces
Correct answer: roller mill — Roller mills crush grain between rollers — compression plus shear — the workhorse of flour milling, unlike the impact shattering of hammer mills. - Which of the following gas is important for climacteric fruits
Correct answer: C2H4 — Ethylene (C2H4) is the ripening hormone; climacteric fruits like mango and banana answer it with a surge in respiration and ripening.