Week 8 : Biodiversity in the supermarket

Question 1

What are the 3 important aspects of food that food processing impacts?

Answer 1

1. Microbial activity
2. Nutrition
3. Sensory quality

Question 2

[NOVEL METHODS]
What is the idea behind high pressure processing (HPP)?

What are the advantages/disadvantages that HPP has on Microbial activity / Sensory quality / Nutrition if any?

Answer 2

Idea : food subjected to high hydrostatic pressure to inactivate/kill certain microbes/enzymes

ᴖ̈ Microbial : Not totally sterilised and require chilled storage

◡̈ Food quality (sensory) : Retains food sensory quality, maintains natural freshness

Question 3

[NOVEL METHODS]
What are some foods that use high pressure processing?

Answer 3

Oysters, ham, smoothies, fruit juices, RTE meals w meat and vegetables

Question 4

[NOVEL METHODS]
What is the idea behind Pulsed Electric Field (PEF)?

What are the advantages/disadvantages that PEF has on Microbial activity / Sensory quality / Nutrition if any?

Answer 4

Idea : food is subjected to pulses of a strong electric field, where foods are placed in chamber between to electrodes

◡̈ Microbial : Achieve microbial inactivation / killing → sterile

◡̈ Food quality : Minimal / no detrimental effect on food quality attributes

Question 5

[NOVEL METHODS]
What are some food applications of Pulsed Electric Field?

Answer 5

Foods that require further processing such as drying / baking (potato chips)

Question 6

[NOVEL METHODS]
What is the idea behind irradiation?

What are the advantages/disadvantages that irradiation has on Microbial activity / Sensory quality / Nutrition if any?

Answer 6

Food subject to irradiation from a distance through exposure to gamma rays (no contact between foods and radioactive materials)

◡̈ Microbial : destroys all microbes (at higher doses only). Can reduce risk of bacterial food poisoning. (for poultry and fresh meat )

ᴖ̈ Sensory quality (depends on type of food)
Minor changes to colour and odour
Softening of fruit and vegetable tissues

ᴖ̈ Nutritional value
Protein, peptides, a.acid are sensitive to irradiation
Loss of amino acids and vitamins
Lipid oxidation occurs

Question 7

There is negativity surrounding irradiation, and people think that irradiation generates harmful substances? Why is this fear irrational (from a scientific POV)?

Answer 7

Though irradiation generates harmful substances such as benzene, but the levels of harmful substances generated is not high enough to cause serious implications (levels of irradiation regulated).

Point i thought of : Furthermore, natural/minimally proessed foods may pose a higher safety risk due to higher microbial load as compared to irradiated food

Question 8

[CHEMICAL PRESERVATIVES]
What is the main purpose of adding chemical preservatives to food?

Answer 8

Preserve food by ensuring microbial quality of food

Question 9

[BIOLOGICAL METHODS]
What are the 2 main biological methods in food processing?

Answer 9

1. Fermentation
2. Enzyme treatment

Question 10

[CHEMICAL PRESERVATIVES]
What are the implications of chemical preservatives on Microbial activity / Sensory quality / Nutrition?

Answer 10

◡̈ Microbial activity : Inhibit microbial growth, extend shelf and improve food safety

◡̈ / ᴖ̈ Sensory Quality : Depends on type of preservative used

◡̈ / ᴖ̈ Nutrition : minimal, but high salt/sugar may cause problems if overconsumed

Question 11

[BIOLOGICAL METHODS]
What are the implications of fermentation on Microbial activity / Sensory quality / Nutrition?

Answer 11

◡̈ Microbial activity : good microbes are used to carry out fermentation, inhibiting harmful MO

◡̈ Sensory quality
Usually perceived to be desirable, changes to texture, aroma of product (small changes to colour too)

◡̈ Nutrition (overall nutritional value of food improves)
Breakdown of complex macronutrients into more digestible forms, improving digestibility
Vitamins may be utilized/synthesized during fermentation

Question 12

[BIOLOGICAL METHODS]

What are the implications of enzyme treatment on Microbial activity / Sensory quality / Nutrition?

Answer 12

ᴖ̈ Microbial : no effects

ᴖ̈ / ◡̈ Sensory quality : changes but depends on enzymes
- ◡̈ : may improve texture/taste as large molecules broken down into smaller ones (e.g. proteins broken down into smaller molecules : less gritty texture and less bitter taste etc
- ᴖ̈ : Enzymes may cause enzymatic browning in fruits etc, which may be undesirable and deemed as a sign of spoilage

ᴖ̈ / ◡̈ Nutrition : Changes but depends on enzymes
- Improved digestibility due to breakdown of large molecules into smaller digestible molecules

Question 13

[FOOD ADDITIVES]
How are ingredients arranged on an ingredient label?

Answer 13

By decreasing order of proportions by weight

Question 14

[FOOD ADDITIVES]

It is not mandatory to declare water as an ingredient on food labels. True or False?

Answer 14

True

Question 15

[FOOD ADDITIVES]
What are the 3 main criteria that a food additive must meet before being added into foods?

Answer 15

1. When there is technological justification for their use
2. No health risks involved
3. Their use does not mislead consumers
   - E.g. if ascorbic acid (vit C) is just used as an anti-oxidant to prevent browning, can’t claim that product is “a source of vit C”

Question 16

[FOOD ADDITIVES]

What is the main difference between food additives and adulterants?

Answer 16

Food additives are added as they serve a particular purpose, and improve properties of food. However, adulterants are added intentionally and do not improve properties of the food and should not be in the food

Question 17

[FOOD ADDITIVES]
Adulterants are always harmful. True or False?
(give examples)

Answer 17

False

Harmless adulterant (but not ethical) : HFCS in honey

Question 18

[PURPOSE OF FOOD ADDITIVES : ENSURING FOOD SAFETY]

What are chemical preservatives?

Answer 18

substance which is capable of inhibiting or retarding the process of fermentation, acidification or other deterioration of food caused by microbes

Question 19

[PURPOSE OF FOOD ADDITIVES : ENSURING FOOD SAFETY]

There are three different classes of food additives. (Class I, Class II, Class III). Which class(es) of preservatives can be found naturally in foods?

Answer 19

Class I and II

Question 20

[PURPOSE OF FOOD ADDITIVES : ENHANCE SENSORY PROPERTIES]

Colorants are all synthetic. True or False?

Answer 20

False, they can be natural too
(from plant/animal/mineral/microbiological colouring)

Question 21

[PURPOSE OF FOOD ADDITIVES : ENHANCE SENSORY PROPERTIES]
What is the difference between a flavouring agent and flavour enhancer?

Answer 21

Flavouring agent is a substance that is capable of imparting taste or odour, or both. (Spices are under the category of flavouring agents)–> impart a taste/odour that may not be present

But a flavour enhancer is a substance capable of enhancing/improving the flavour of food, which excludes sauce/gravy/spice/condiments etc. (does not impart taste but only enhances current flavour in food)

Question 22

[PURPOSE OF FOOD ADDITIVES : ENHANCE SENSORY PROPERTIES]
Give an example of flavour enhancers.

Answer 22

Mono-sodium L-glutamate (MSG), di-sodium 5’ isosinate, disodium 5’ - guanylate

Question 23

[PURPOSE OF FOOD ADDITIVES : ENHANCE SENSORY PROPERTIES]
What is a sweetening agent? What kinds of substances are not considered as sweetening agents?

Answer 23

Any substance added to food in place of sugar to provide a sweet taste
- does not include aspartame, sugar, carb, polyhydric alcohols

Question 24

[PURPOSE OF FOOD ADDITIVES : ENSURING FOOD QUALITY BY REDUCING CHEMICAL AND PHYSICAL DETIORATION]

What is an antioxidant?

Answer 24

Any substance which delays, retards or prevents the development of rancidity / other flavour deterioration in food due to oxidation

• e.g. ascorbic acid, citric acid, tocopherol

Question 25

[PURPOSE OF FOOD ADDITIVES : ENSURING FOOD QUALITY BY REDUCING CHEMICAL AND PHYSICAL DETIORATION] A sequestrant is sometimes labelled as an antioxidant on food ingredient labels. What is a sequestrant and its purpose?

Answer 25

Any substance which combines with metal ion in the food to render metal ion inactive. (transition metals catalyse oxidative rancidity) Purpose is to stabilise certain characteristics such as colour, flavour, texture

Question 26

[PURPOSE OF FOOD ADDITIVES : ENSURING FOOD QUALITY BY REDUCING CHEMICAL AND PHYSICAL DETIORATION] What is a humectant and its purpose? What kind of foods is it usually used in?

Answer 26

Any substance which absorbs moisture and maintains the water content of the food. Purpose : chemical – to prevent food from staling / becoming too tough (esp in bread, cakes) - Typically used in baked goods, confectionery, and meat products

Question 27

[PURPOSE OF FOOD ADDITIVES : ENSURING FOOD QUALITY BY REDUCING CHEMICAL AND PHYSICAL DETIORATION] What is a common example of a humectant?

Answer 27

Glycerin (aka glycerol) - polyphosphates in meat (recall water lect for fst2102b)

Question 28

[PURPOSE OF FOOD ADDITIVES : ENSURING FOOD QUALITY BY REDUCING CHEMICAL AND PHYSICAL DETIORATION] In what 2 ways are gaseous packaging agents used ?

Answer 28

Any substance used as an aerating agent / propellant in storage or packaging of any fluid food OR To displace air in a sealed package or in a place of storage, in the storage or packaging to any food

Question 29

[PURPOSE OF FOOD ADDITIVES : ENSURING FOOD QUALITY BY REDUCING CHEMICAL AND PHYSICAL DETIORATION] What are the physical and chemical purposes of gaseous packaging agents?

Answer 29

Physical : e.g. MAP in chips → prevents potato chip bags from being squashed and chips wont be crushed Chemical : reduce O2 thus reducing oxidative rancidity (chemical deterioration)

Question 30

[PURPOSE OF FOOD ADDITIVES : ENSURING FOOD QUALITY BY REDUCING CHEMICAL AND PHYSICAL DETIORATION] What is an anti-caking agent?

Answer 30

Any substance which when added to powder food prevents caking of food

Question 31

[PURPOSE OF FOOD ADDITIVES : ENSURING FOOD QUALITY BY REDUCING CHEMICAL AND PHYSICAL DETIORATION] What is anti-foaming agent and what purpose does it serve?

Answer 31

A substance which prevents / reduces foaming of food Purpose : physical → appearance - E.g. in apple juice → A customer may perceive aple juice with a layer of foam on top to be spoilt

Question 32

[PURPOSE OF FOOD ADDITIVES : ENSURING FOOD QUALITY BY REDUCING CHEMICAL AND PHYSICAL DETIORATION] What is a emulsifier/stabiliser and what purpose do they serve?

Answer 32

A substance which is capable of aiding the formation of (emulsifier) and in maintaining (stabiliser) the uniform dispersion of 2 or more immiscible substances (e.g. oil and water) - Purpose : physical -- prevent separation of immiscible layers which could be perceived as a sign of spoilage (but its not)

Question 33

[PURPOSE OF FOOD ADDITIVES : NUTRITION] What is a nutrient supplement?

Answer 33

Any amino acid, vitamin or mineral which enriches/improves nutrition content of food when added singly or in combination

Question 34

[PURPOSE OF FOOD ADDITIVES : GENERAL PURPOSE] What is shellac used for?

Answer 34

Shellac (wax) added as an edible layer of coating to increase shelf life of apples - Coatings can inhibit the growth of microorganisms during food storage, control gas exchange, water penetration, and oxidation processes in food

Question 35

[FOOD ADDITIVES] E numbers may appear on an ingredient's list. What are E numbers and what does it mean?

Answer 35

E-number is a number used in European Union to identify permitted food additives. E number means that an additive has passed safety tests and is approved for use