1102 EXAM Flashcards

1
Q

Factors affecting food choices

A

Physical- affects ability to detect flavours
= body chemistry, taste buds, age, gender

Physiological- taste bias due to past experiences
= brand, advertisement, peers, setting

Cultural- beliefs+ behaviours influence food exposure+ preferences
= religious practices, lifestyle, holiday traditions

Environmental- availability, economical
= Geography, climate, costs, obtainability, we tend to prefer foods that we have been exposed to in childhood

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2
Q

Super- tasters

A

strong dislikes& fussy but good detection

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3
Q

Medium- tasters

A

like all foods, sometimes fussy, may detect well

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4
Q

Non- tasters

A

cannot detect, not fussy, depend on smell and presentation

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5
Q

types of sensory tests

A

Affective= untrained consumers/ panelists so can detect individual preferences

Analytical= Detect differences, minimal training required

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6
Q

how to prepare for sensory evaluation

A
  • away from cooking and smells
  • all samples look identical
  • rinse w water first
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7
Q

ideal participant characteristics for sensory evaluation

A
  • No cold/ flu
  • No chewing gum immediately beforehand
  • Haven’t ingested food w/in an hour before testing
  • Nonsmokers
  • Not colour blind
  • Good mixture of people
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8
Q

VISUAL physical evaluation tests

A

Microscope= observes microorganisms, starch granules, sugar/ salt crystals etc.

Spectroscopy= Measures colour in foods by detecting amount + wavelength of light transmitted through a solution

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9
Q

WEIGHT/ VOLUME, CONCENTRATION Physical evaluation tests

A

Refractometer: sugar concentration- determines the angle of polarised light passed through the solution

Spectroscopy= AAS- measure minerals content

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10
Q

TEXTURE, VISCOSITY physical evaluation tests

A

Linespread test- measures viscosity of viscous foods

Penetrometer- stimulates teeth biting

Shortometer- measures resistance of baked products

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11
Q

What is the Kjeldhal method used for

A

used to measure protein content

Food industry- accurate labeling+ product quality

Animal Feed- balanced diet+ maintain feed quality

Agriculture- assists in selecting high- protein crop varieties

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12
Q

Steps in the Kjeldahl Method

A
  1. Digestion: The sample is mixed with sulfuric acid to break down organic matter, converting nitrogen into ammonium sulfate.
  2. Distillation: The digest is then made alkaline, releasing ammonia. This ammonia is distilled and captured in a boric acid solution.
  3. Titration: Finally, the amount of ammonia is measured by titration with a known concentration of acid, usually hydrochloric acid. The amount of nitrogen is then calculated, and a conversion factor (often 6.25) is applied to estimate the total protein content.
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13
Q

What is Benedict’s test used for

A

detect the presence of reducing sugars, such as glucose, fructose, and lactose, in a sample.

Food Industry: Used to assess sugar content in foods and beverages.

Medical Diagnostics: Sometimes used to detect glucose in urine, which can be an indicator of diabetes.

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14
Q

Benedict’s Test procedure

A
  1. Preparation: Benedict’s reagent, a bright blue solution containing copper(II) sulfate, is added to the sample.
  2. Heating: The mixture is heated in a water bath.
  3. Observation: If reducing sugars are present, the solution changes color:
    Green: low sugar concentration
    Yellow to orange: moderate sugar concentration
    Red or brick red precipitate: high sugar concentration.
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15
Q

what is the Iodine Test used for

A

Detect the presence of starch

Food Industry: To test starch content in processed foods.

Botany: To observe starch storage in plant cells.

Education: Commonly used in labs to demonstrate carbohydrate detection

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16
Q

Iodine Test Procedure

A
  1. Preparation: A few drops of iodine solution (usually potassium iodide with iodine) are added to the sample.
  2. Observation: If starch is present, the iodine reacts with it, producing a color change:
    Blue-black: Indicates the presence of starch.
    Yellow-brown (no color change): Indicates that starch is absent or present in very low amounts.
17
Q

Cooking

A

the transfer of energy from a heat source to a food

Destroys pathogens to reduce illness

Changes molecular structure of foods

18
Q

Ripening

A

result of enzyme activity+ ethylene gas

Chlorophyll degrade, flavour changes, nutrient changes

19
Q

Spoilage

A

Microorganisms prefer high sugar-> natural decomposition-> food lost

Enzymes: rancidity, off- odour, off- taste

Water loss- dehydration, loss of flavour

Decreased eating quality- sensory changes

20
Q

What are the functions of food packaging

A

protection, Containment, communication, food safety, production efficiency, environmental impact, convenience, food availability

21
Q

Primary Packaging

A

direct contact with food products

-consumers see the most
food safety requirements
e.g metal cans, bottles

22
Q

Secondary Packaging

A

protection against physical abuse

23
Q

Tertiary packaging

A

distribution of packaged foods
- never seen by customers

24
Q

Quaternary Packaging

A

distribution of packaged foods
- never seen by customers
e.g shipping containers

25
Q

blanching

A

quick cooking technique that involves briefly boiling food and then plunging it into cold water to preserve its color, texture, and nutrients, often used for vegetables before freezing or further cooking.

destroys enzymes+ reduces microbial load
- hot water 89-99 degrees
- steam 100 degrees
- time varies depending on food

26
Q

Pasteurisation

A

heat-treatment process that kills harmful bacteria in food and beverages, particularly dairy, by heating them to a specific temperature for a set period without affecting their quality.

destroys enzymes and reduces pathogens
- high temp, short time
var

27
Q

sterilisation- canning

A

food preservation method that involves sealing food in airtight containers and then heating them to high temperatures to kill all microorganisms, including bacteria and spores.
- extends shelf life

28
Q

slow freezing

A

preservation method where food is frozen gradually, forming larger ice crystals that can affect texture but still extend shelf life.

-18- -25degrees
- 3 hours

29
Q

Fast freezing

A

food is frozen rapidly at very low temperatures, creating small ice crystals that help preserve its texture, flavor, and nutrients better than slower methods.

-18- -40degrees
-5-10 min

30
Q

Freeze- drying

A

food is frozen and then subjected to a vacuum, causing the ice in the food to sublimate directly from a solid to a gas, bypassing the liquid phase
- removes moisture while retaining the food’s original structure, nutrients, and flavor, making it lightweight and shelf-stable for long-term storage without refrigeration

31
Q
A