Food between farm gate and consumption

Question 1

Compare food processing and food preservation

Answer 1

Food processing: – Conversion of raw animal and plant tissue into forms that are convenient and practical to consume – All the operations from field and farm to consumers • Food preservation – Use of specific thermal and non-thermal techniques to minimize the number of spoilage and pathogenic microorganisms in foods, making them safe and extending the shelf life

Question 2

What are the 12 unit operations?

Answer 2

1. Materials Handling 2. Seperating 3. Cleaning 4. Disintergrating 5. Pumping 6. Mixing 7. Heat exchange 8. Evaporation 9. Drying 10. Forming 11. Packaging 12. Non-thermal methods

Question 3

What is materials handling?

Answer 3

From farm to harvest. Transport to processor. Movement within a plant of conveyor belt. Distribution of processed product

Question 4

What is separating?

Answer 4

-solid from liquid…. ex) peeling potatoes, juice from oranges, oil from water, air removal. Sorting good from bad.

Question 5

What is cleaning?

Answer 5

Brushing off micro filtration of bacteria from a liquid. Plant equipment and surfaces.

Question 6

Disintegration?

Answer 6

Subdivision of food into smaller particle size. ex) grinding,cutting,dicing,roller mixing. ex) Homogenizing oil/water mixture to create emulsion.

Question 7

Pumping?

Answer 7

Moving semi-solid paste or liquids in the plant in pumps.

Question 8

Mixing?

Answer 8

Wide range for materials (solid, liquid, gas). and for purpose (dispersion of ingredients, emulsifying, whipping air into foam)

Question 9

Heat exchange

Answer 9

Application or removal of heat ex) cooking, canning, pasteurization, freezing. These must be very efficient for mix heat loss.

Question 10

Evaporation?

Answer 10

Removal of moisture from food to concentrate its solids. ex evaporated milk, juice concentrates. Often under vacuum so lowers boiling pt.

Question 11

Drying?

Answer 11

For more extensive moisture removal than evaporation -tunnel or cabinet (solids) -Spray drying (liquids)

Question 12

Describe spray drying….

Answer 12

Question 13

Forming?

Answer 13

Formation of specific shapes of foods

ex) burger patties, breakfest cereal, pasta.

Question 14

Why package food?

Answer 14

Provides protection from

• Microbial contamination
• physical dirt
• insect
• light
• air (ox)
• Moisture gain or loss
• Can be good marketing tool

Question 15

What does high pressure porcessing do?

Answer 15

It is a non-thermal food preservation method (NO HEAT).

Used high pressure to destroy pathogenic bacteria.

Question 16

What is gamma irradiation?

Answer 16

Non-thermal food preservation method. The radiation kills all bacteria and can make fruit and veg last way longer before going bad naturally.

Question 17

What is controlling? (13th unit operation)

Answer 17

Controlling-

to continuously measure the steps to make sure that desired product remains quality. ex) valves, thermometers, scales….

On-line analysis and adjustments.

Question 18

The NEW definition of food processing….?

Answer 18

The systematic combination of unit process operations into a complex total processes.

Question 19

Describe the three types of food deteriorations:

Physical deterioration

chemical deteriration

biological deterioration

Answer 19

Physical deterioration- Phase seperation, undesired drying, loss of structure and damage due to handling

chemical deterioration- Undersired chem rxns in food, enzymatic action, lipid oxidation, toxins.

biological deterioration- microbial growth and food spoilage.

Question 20

What are the 9 major causes of food deterioration?

Answer 20

1. Growth and activity of microorganisms,

primarily bacteria, yeast and molds – Food spoilage and food safety issues

2. Activity of endogenous food enzymes and other

chemical reactions within the food itself – Lipoxygenase catalyzes lipid oxidation, PPO for enzymatic browning

3. Infestation by insects, parasites and rodents – (5-10% in North America, >50% some countries)
4. Inappropriate temperatures for a given food, both heat and cold – e.g., chill injury for bananas, cucumbers and tomatoes can occur below 10°C
5. Gain or loss of moisture • Surface moisture controlled by humidity in air around food and barrier properties of the package
6. Reaction with oxygen – Oxidation of nutrients (vitamin A and C, essential fatty acids), colours, flavours, mold growth
7. Exposure to light – Light induced oxidation
8. Physical stress or abuse
9. Time - specific time interval when quality is the highest

Question 21

What are the two most common preservation techniques used?

Answer 21

Heating (thermal processing)

-freezing

Question 22

Describe what these food preservation strategies do?

Dehydrating/drying

Acidification

Fermentation

Answer 22

Dehydrating/drying- prevents microorganism growth by removal of water

Acidification- Gives foods with high degree of acidicty longer perservation (pickles)

Fermentation- Desirable microbial growth that can lead to chem and physical changes that help in preservation. Can also add new flavour and colour. (yogurt, cheese, beer, bread)

Question 23

Describe what these food preservation strategies do?

• Smoking
• Modificed/controlled atmosphere packaging

Answer 23

smoking- kill surface bacteria (wood burning produces antimicrobial components). Surface drying. Smoked flavour. Heating increases spoilage control.

Modified/controlled atmosphere packaging- Increase shelf life by controlling the gas environment in direct contact with the product. Can control anaerobic pathogenic bacteria.

Question 24

Examples of different types of chemical preservatives:

Traditional?

Acidulant?

Gaseous?

Antioxidants?

Answer 24

Traditional – Salt, Sugar

• Acidulants – Benzoic acid salts, sorbic acid salts, lactic acid
• Gaseous – SO2, CO2
• Antioxidants – Vit E, ascorbic acid, BHT, TBHQ, BHA

Question 25

What are the three main mechanisms by which heat is transferred?

Answer 25

Conduction, convection and radiation

Question 26

Describe conduction

Answer 26

Conduction

– Heat energy is transferred from one molecule to an adjacent molecule (through containers)

without a gross change in the relative positions of the molecules

– Heating of solid foods

Question 27

Describe convection

Answer 27

Convection

– Transfer of heat by groups of molecules that move as a result of differences in density or as a result of agitation

– Heating of fluid foods

Question 28

Describe radiation

Answer 28

Radiation

– Heat transfer by electromagnetic waves emitted by hot objects (infrared range, wavelength 750 nm to 1 mm)

– Infrared, microwave, dielectric heating

Question 29

What is the primary objective to cooking?

Preservative changes?

Other desierable changes?

Undesirable changes?

Answer 29

What is the primary objective to cooking? In crease palatability. Baking, roasting, dry heat

Preservative changes? Some destruction of spoilage and pathogenic microrganisms. Inactivation of deteriroative enzymes

Other desierable changes? Inactivation of some anti-nutritional factors (Lectins in pulses). Improved digestability of some food constitients

Undesirable changes? Loss of nutrients. Decline in sensory quality (with too much heating).

Question 30

How is there nutirent loss during cooking?

Answer 30

• Lysine bioavailability reduced by nonenzymatic browning
• Heat sensitive vitamins: decrease in bioavailability (not concentration) – vitamin A, vitamin D
• Loss of water soluble vitamins: decrease in concentration (and bioavailability) – thiamine, niacin, folate

Question 31

What is the main objective of blanching and how is it done?

Answer 31

Main objective- inactivate deteriorative enzymes. Kill spoilage bacteria.

Atmospheric or pressurized steam.

Less severe than canning

Normally done prior to freezing or canning of veg and drying of fruit.

Question 32

What are the purposes of blanching prior to freezing or canning?

Blanching of fruits before drying?

Answer 32

Question 33

How are these enzymes inactivated during blanching?

Lipoxygenase

Polyphenol oxidase

Pectinase

Answer 33

Question 34

How is nutrient loss during blanching indicated?

Answer 34

Loss of nutrients during blanching is mainly due to leaching, thermal destruction, oxidation

• As ascorbic acid is water soluble it is often leached from cells. It is also thermally labile and subject to enzymatic breakdown.
• Therefore, loss of ascorbic acid is used as an indicator of the severity of the blanching process

Question 35

When is there the least amount of loss during blanching?

Answer 35

Blanching with steam and air cooling (instead of rinsing)

Question 36

What does pasterurization do?

Answer 36

A heat treatment which kills part of the microbial population present in a food – Minimum changes in sensory or nutritive value

• Pasteurization of milk – Primary objective is to kill pathogenic microorganisms; shelf life is extended due to reduction in spoilage organisms and deteriorative enzymes – Target pathogens: was Mycobacterium tuberculosis (TB), now Coxiella burnetti (Q fever)

Question 37

What are the two equivalent processes in terms of microbial kill?

Answer 37

LTH (low temp, hold) = 63°C for 30 min

–> LTH is more detrimental to nutritional and sensory properties.

HTST (high temp, short time or flash) = 72°C for 15 sec

Question 38

What is the difference between the batch process and the continuous process of pasterization?

Answer 38

Batch process

– Milk is heated in holding tank for a certain time

– Used only in small-scale operation

• Continuous process

– Milk flow through a heat exchanger while the desired time/temperature treatment is obtained

– Equipment: Plate heat exchanger (PHE) • High production rate

• No overheating of milk

Question 39

What foods other than milk are pasterized?

Answer 39

Beer, juice, eggs

Question 40

What is steriization?

Answer 40

Sterilization or “commercial sterilization” is the process used in canning, retorting and UHT (ultra high temp) processing of food

– Done at a much higher temperature than pasteurization

• It is also called Appertization, after the French scientist Nicolas Appert, who in 1810 won a prize from Napoleon for discovering way to preserve food by enclosing in hermetically sealed containers

Question 41

What are other types of microorganism destruction processes?

Answer 41

Question 42

What counts as

low-acid food?

acid?

high-acid foods?

Answer 42

Low-acid foods (pH > 4.5)

– Acid foods (pH 3.7 to 4.5)

– High-acid foods (pH < 3.7)

Question 43

Cannning of low acid foods.

Answer 43

Question 44

Canning of acid foods?

Answer 44

Question 45

Canning of high acid foods?

Answer 45

Question 46

What is so great about UHT sterilization?

Answer 46

Question 47

Why exactly do we fucking love Tetra Pak’s??????

Answer 47

ASEPTIC packaging!!!!

Question 48

What must be taken into consideration for heat transfer during commercial sterilization?

Answer 48

Heat transfer during sterilization of cans in retort occurs via:

– Conduction through can wall and solid foods

– Convection through liquid foods

• Need to make sure the cold point (x) has reached desired temperature and time

Question 49

What is thermal conductivity?

Answer 49

Thermal conductivity is a measure of how fast a solid material can be heated

Question 50

What is specific heat capacity (Cp)

Answer 50

The amount of heat energy required to raise the temperature of a mass unit of a substance by 1 degree celcuis

Question 51

What are some factors that influence the severity of the thermal process required to commercially sterilize?

Answer 51

– Nature and heat resistance of the microbial population

– Initial microbial load (How many microbes are present?)

– Nature of the food (pH, chemical composition)

– Heat transfer characteristics of the container

– Heat transfer characteristics of the food

– Conditions of storage (liquid? How will it be stored?)

– Characteristics of the canning equipment • “still” retort vs. one with agitation

Question 52

What does the survivor curve demonstrate?

Answer 52

The survivor curve is the logarithmic releationship betweeen the number of survivors of a given microorganism and the time oh heat at that given temp

This is because the number of microorganisms in a food is reduced when it is subjected to heat treatment for a certain time.

Question 53

For thermal resistance of microorganisms:

T/F

The more time needed to decrease the microbial population at a given temp, the more heat resistant it is.

Answer 53

True

-The slope of this curve (survival rate per unit time) is related to sensitivity/resistance of the the microorganism to heat.

Question 54

How is heat resistance of microorganisms expressed?

Answer 54

The heat resistance of microorganisms is expressed in terms of the time needed to kill 90% at a given temperature

-D-value

Question 55

What is the D-Value?

Answer 55

D value (decimal reduction time)

-The number of minutes required at a particular temperature and in a particular medium to destory 90% of the microorganisms (10% survival) in a population

–> or to decrease the population by one log cycle

Question 56

What is the practical use of D-values?

Answer 56

If we know the d-value at a particular temp for our target organism and the number of organisms present, we can calculate how long it will take to destory the entire population

Often assume that there are 10^12 of an initial bacterial population, since we don’t usually know how many are initially present.

–> So we heat for 12 x D, which is known as a 12 D process. To kill all the bacteria present!

Question 57

What are some factors affecting D value (before, during and after processing?)?

Answer 57

Before processing: Type of microorganism, growth temp, medium and phase

During: Type of food, pH, water activity, salt concentration. Concentration of microorganism (how much is present before processing?), rate of heating

After processing: Recovery medium (can they recover after processing?), temp. Presence of oxygen. Background microflora chance of growth in the medium?)

Question 58

What are the effects of thermal processing on food constituents?

Answer 58

Acid and salt accelerate the destruction of microorganisms

Protein denaturation (during processing)

Generation of cooked flavour due to reaction of sulfur (S) from amino acid cysteine

Maillard Browning reaction between reducing sugars and proteins-loss of nutirents (and important AA’s)

Loss of heat sensative vitamins

Question 59

How do we measure thermal destruction of nutrients in food?

Answer 59

Also D-value

D-valuse for nutirent: decimal reduction time for nutrient degradation at retort temp

Bacterial cells and spores are more heat sensative than nutrients

Imporved nutrient retention can be achieved with a high temp short time (HTST) process. -accelerated lethal rate at high temp. -Shorter process time prevents nutrient degradation form proceeding very far.

Question 60

What are 4 pieces of equipment that can be used for thermal processing?

Answer 60

Question 61

What is the most setisfactory method currently available for long-term food preservation?

Answer 61

Freezing

Refers to storage of food at temperatures between -18 and -30 degrees celcius.

Freezing reoves free water required for microbial growth.

Question 62

What is the process of freezing?

Answer 62

-Removal of sensible heat until freezing temperature

– Removal of latent heat of fusion leading to ice formation

– Further removal of sensible heat towards storage temperature

Question 63

What is the difference is ice crystal size of a fast freeze vs a slow freeze?

Answer 63

Fast freeze= numerous small ice crystals

Slow freeze= fewer, but larger ice crystals

Question 64

Where do ice crystals first form in forzen vegetable tissues?

Answer 64

Ice crystals first form between the cells, as they have lower concentration of solutes there.

Question 65

The effect of slow freezing (home freezer) on vegatables

Answer 65

1. Large ice crystals damage cellular structure of frozen vegetables and lead to loss of structural integrity (food becomes very soft)
2. Formation of large crystals in inter-cellular region of vegetables pulls water out of the cell (due to osmotic equilibrium) - results in cellular dehydration. –> Ice crystals outside of the cell will force free water out of the cell to maintain equilibrium.
3. On thawing the cells unable to maintain rigidity due to dehydration and disruption of cell wall by ice crystals – leading to soft, flaccid texture and loss of water

Question 66

Effects of rapid freezing?

Answer 66

–> Many small ice crystals, and all freeze together

• Rapid freezing results in higher ice crystal nucleation rate which lead to formation of numerous small ice crystals both outside and inside the cells of frozen vegetables
• Cells maintain their rigidity and minimizes drip loss of water during thawing of frozen vegetables
• However, disruptive effect of size of ice crystals is minimum in fish or meat (muscle food) due to the elasticity of the cellular structure in muscles

– The mechanism of loss of quality due to slow freezing of muscle foods is different than fruits and vegetables

Question 67

What quality issues arrive from frozen muscle food?

Answer 67

Loss of quality of muscle food is due to denaturation of muscle proteins

– During freezing unfrozen region become concentrated with enzymes and and acids which denatures muscle proteins and affect its functionality

– Increased salt concentration in the unfrozen water also produces protein denaturation

• This denaturation of protein occurs during formation of ice crystals in slow freezing in the temperature range 0º to -5ºC
• This can be avoided by rapidly freezing the product (meat) such that the ice crystal formation zone (0º to -5ºC) passes as quickly as possible

Faster freezing is better for muscle foods and veg.

Question 68

What 5 things affects the rate of freezing?

Answer 68

1. temperature differential between the food and cooling medium
2. heat transfer rate of cooling medium (air or refrigerant)
3. surface area of food
4. product thickness
5. Agitation of liquid product

Question 69

What effect can chemical changes have during freezing?

Answer 69

In frozen food products enzymes remain active, so unwanted enzyme activity in the frozen state may lead to loss of colour, flavour, lipid oxidation and also loss of nutrients

• To avoid this, vegetables must be blanched prior to freezing
• For fruits, if blanching is not option, ascorbic acid can be added to stop enzyme activity in frozen state

Question 70

What must be taken into consideration for microbiological activity for freezing food?

Answer 70

– The process of freezing does not significantly kill microorganisms already present in food

– Blanching prior to freezing kills some microorganisms

– During freezer storage, the growth of microorganisms significantly reduced and a gradual decrease in their number can be observed

– However, often there can be sufficient survivors that can multiply and give problem during the thawing process

– Temperature fluctuation during frozen storage can also lead to similar problem

Question 71

What causes freezer burn?

Answer 71

Decrease in humidity in freezer may lead to sublimatation of ice on food surface= freezer burn

-Loss of food weight, dry out surface (discolouration, protein dentaturation), loss of texture, rancidity development.

Question 72

How to prevent freezer burn?

Answer 72

Relative humidity inside the freezer should be kept above 90%. REduce air movement across the food prodcuts.

Glazing of food prior to freezing. Glazing is the formation of a layer of water or aq sol’n on food surcae that turns into an ice coat during freezing. Glaze layer protects food from loss of moisture and prevents freezer burn.

Use of food packaging, prevents freezer burn and oxidation.

Question 73

What type of freezer?

Answer 73

Air-blast freezer and tunnel freezer.

Air blown over, air frozen.

Question 74

What kind of freezer?

Answer 74

Belt freezer (spiral belt freezer). Rotating belt, mostly for frozen meat.

Question 75

What kind of freezer?

Answer 75

Fluidized-bed freezer.

Cold air spray from bottom, fluid bed on top to freeze product.

Question 76

What kind of freezer?

Answer 76

Scraped-surface freezer

Widely used for ice cream manufacturing.

Food froen on surface and scraped off by blade as freezes.

Question 77

What type of freezer?

Answer 77

Cryogenic freezing

Cooling with liquid nitrogen (-196 degrees C) or dry ice (solid CO, -79degrees C) or liquid ammonia (-33 degrees C)

RAPID freezing.

Question 78

What type of freezing does IQF stand for?

Answer 78

Individual quick freezing

Foods frozen individually for ease of consumer use. Rapid freezing with small ice crystal formation.

Dehydration may be a concern, water sprayed before freezing (glazing) to control drying. Amount of water gain must be regulated.

Question 79

What are three things to consider for freezing vegatables?

Answer 79

What are three things to consider for freezing vegatables?

• Blanch prior to freezing (to inactivate damaging enzymes)
• Small loss of nutrients while freezing
• On thawing, there may be more leaching compared to fresh veg.

Question 80

What are 2 things to consider for freezing fruits?

Answer 80

During frozen storage, some loss of vit C will occur.

On thawing, substancial vitamin loss happens in fruit syrup/juices, unless you consume it!

Question 81

What are the digestible and indigestable structural aspects of fruits and veg?

Answer 81

Most fruits and vegetables are high in water, low in proteins and fats

• They are good sources of carbohydrates

– Digestible: sugars and starches

– Indigestible: cellulose, hemicellulose, lignin and pectic materials

• Cell wall of young plants are relatively thin and composed largely of cellulose held together by pectin
• With aging the wall thickens and higher amount of tough fibrous hemicellulose and lignins are formed

Question 82

Fruits are a good source of which things?

Answer 82

Fruits are generally good source of:

– Specific vitamins and minerals

– Natural sugars

– Organic acids

– Flavor compounds

– Bioactive phytochemicals

Question 83

The colour found in chloroplasts and chromoplasms is a result of which 3 pigments?

Answer 83

Question 84

What are climacteric fruits vs non-climacteric fruits?

Answer 84

Climacteric fruits- Harvested immature so that they may ripen by the time of consumption. Can ripen during shipping. (apples, bananas, melon, tomatoes)

Non-climacteric fruits- Are harvested in fully ripened state and msut be consumed quickly. Don’t ripen during storage, can’t ripen off the tree. (Grapes, strawberries, citrus fruits)

Question 85

Describe fruit and vegatables in terms of:

Growth phase, maturation, ripening and senescence

Answer 85

Growth phase encompasses cell division and enlargement causing an increase in size

• Maturation, reached at the end of growth phase, is exhibited by increase in sweetness, softness, colour and flavour development
• Ripening happens due to natural physiological processes under enzymatic and hormonal control – Both physical and chemical changes in fruits
• Senescence is the phase associated with deteriorative process, caused by aging, tissue death and associated with loss of quality (over-ripe and inedible)

Question 86

Why is ethylene important? What is the effect of ethylene on F&V?

Answer 86

• Ethylene is a plant hormone that plays key role in ripening and senescence of F & V
• All plant cells produce low level of ethylene, but any external stress (wound, bacteria and fungi attack) can stimulate ethylene synthesis and release
• Effect of ethylene on F & V – Chlorophyll is broken down, new pigments surface – Acids are broken down – fruit changes from sour to neutral

to sweet – Amylase degrades starch to sugar – The breakdown of pectin between the the cells unglues them so they can slip past each other hence the softer fruit – Breakdown of large organic molecules to produce the aroma and tastes we associate with ripe fruit.

Question 87

What is the effect of ethylene on climacteric fruits vs non-climacteric fruits?

Answer 87

Climacteric fruits produce high level of ethylene during ripening – Exposure to exogenous ethylene may lead to acceleration of ripening and senescence

• Non-climacteric fruit (e.g., citrus fruits) do not produce ethylene during ripening process but respond to exogenous ethylene by softening and increasing respiration rate – It does not promote natural ripening – In order to improve external skin colour and market acceptance, these fruits can be treated with ethylene, as a de-greening agent – Ethylene treatment breaks down the green chlorophyll pigment on the exterior part of the peel and allows the yellow or orange carotenoid pigments to be expressed

Question 88

Why must climacteric fruit’s respiration be montored closely during ripening?

Answer 88

– Without careful temperature control, fruits will rapidly over-ripen and senesce

– Failure to control respiratory heat also can increase water loss from the produce

– Furthermore, the increased warmth and moisture levels developed during respiration may lead to increased bacterial and fungal infections

–> Temp needs to be controlled so this is slowed down!

Question 89

Why are they changes in chlorophyll due to cooking of vegetables?

Answer 89

Why are they changes in chlorophyll due to cooking of vegetables?

Question 90

How does water loss change quality of fresh produce?

Answer 90

• Water loss

– Structure and thus textural properties of fresh produce dependent on the moisture level inside the cells

– If too much water is lost from the tissues wilting or wrinkling of the product will occur

– The speed of post-harvest water loss is dependent primarily on the external vapour pressure

• Other factors for water loss

– Products with a large surface to volume ratio such as leafy crops will lose a greater percentage of water far quicker than large spherical fruits

– Fruits with thick peels can lose a considerable amount of moisture from the skin without compromising edible quality (citrus species, bananas)

Question 91

How do fungal and bacterial growth affect quality of fresh produce?

Answer 91

Fungal and bacterial growth

– The most important microorganisms causing postharvest wastage of fresh produce are fungi

– This is particularly true for fruits, where relatively acidic conditions tend to suppress bacterial growth

– Vegetables with a higher pH can, however, suffer high losses from bacterial infections

Question 92

How do physical injuries affect the quality of fresh produce?

Answer 92

– The most important cause of loss in fresh produce

– The wound is an ideal entry point for many post-harvest pathogens

– Physical injury stimulates ethylene production in plant tissues, which can lead to premature yellowing or ripening of commodities

– Brown spots on over-ripe or injured bananas are due to over exposure to ethylene

• Degradation of yellow pigments into brown
• This is different from enzymatic browning of cut F & V due to PPO

Cover the top of banaa with aluminum foil, not at much ethelyene will be converted. will ripen slower. Keep banana, pears and apples sepereate. Do not keep the different climacteric f and v together, will turn eachother

Question 93

What does pre-cooling mean?

Answer 93

Precooling to remove field heat as quickly as possible after harvest. Essential for highly perishable products.

ex) Icing, room or forced air cooling, hydrocooling (water)

Question 94

What is the benefit of surface coating and wraps for fresh produce?

Answer 94

– Many fruits and vegetables benefit from a surface coating which can slow down the loss of moisture

– Coatings can also reduce the movement of gas in and out of the products

– Many of the coatings applied are derived from plant extracts: carnauba, shellac or other natural waxes (for apples)

Question 95

What is irradiation, what does does it do to fresh produce?

Answer 95

Irradiation- not allowed in Canada fro fresh f&v

– Application of gamma ray or high energy electrons to fresh produce

– Sprout inhibition in root, tuber and bulb crops

– Control of some fungal diseases

– Increased storage potential through delays to the ripening processes of fruits

– In practice, very little fresh produce is actually irradiated owing to both these consumer concerns and legislative restrictions

Question 96

What is controlled atmosphere storage?

Answer 96

Packaging where respiration can be controlled in many crops by reducing the levels of oxygen

Can also be controlled by raising the levels of carbon dioxide.

Packaging may also be conventional to reduce physical damage of sensative products.

Question 97

What is MAP and what does it stand for?

Answer 97

Modified atmosphere packaging (MAP) by Polymeric films

– Provide a barrier to the spread of decay from one unit to another

– These films will also affect the movement of respiratory gases depending on the relative permeability of the film

– This can lead to the development of lowered O2 and raised CO2 levels within the package

– Reduce the respiration of the produce and potentially extend shelflife.

Question 98

How do MAP films work?

Answer 98

Question 99

What are the difference between active modification and passive modification of MAP products?

Answer 99

A modified atmosphere can be created within the pack in two ways:

• Active modification involves the pulling of a slight vacuum within the pack and then replacing the atmosphere with the desired gas mixture

– Absorbers of CO2, O2 or ethylene may be included within the pack to control the concentration of these gases. (force gas mixture into package)

• In passive modification systems, the atmosphere is attained through the respiration of the products within the pack. (Passively by the respiration of the fruit and veg)
• Temperature control is extremely important with MAP, as this will influence the gas permeability properties of the film as well as the respiration rate of the product

Question 100

What is the difference between the primary and the secondary packaging material?

Answer 100

Primary packaging material remains in direct contact with the food

Secondary packaging material may also be used for convenience, and protective purpose, and for printed material.

Question 101

What are the primary functions of food packaging?

Answer 101

• Preservation
• Protection against physical damage
• Protection against chemicals, dirt and biological contamination
• Aiding distribution to consumer
• Create or enhance sales appeal (marketing)

Question 102

What are teh 10 golden rule fro food packaging?

Answer 102

Question 103

What are the 6 functional requirements of packaging materials?

Answer 103

• Gas permeability

– OTR, oxygen transmission rate

– WVTR, water vapor transmission rate

• Protection against environmental factors (light, odor, microorganisms, moisture)
• Mechanical properties (e.g., film strength, weight)
• Reactivity with food (grease, acid, water, color)
• Marketing-related (printability, cost)
• Convenience (disposability, re-sealability)

Question 104

What do these recycling plastic coding systems mean (USA, 1988).

Answer 104

Question 105

What do these recycling plastic coding systems mean (USA, 1988)?

Answer 105

Question 106

What are the three main gases used in MAP?

Answer 106

Oxygen, carbon dioxide and nitrogen

Question 107

What are some advantages and limitations of MAP?

Answer 107

Question 108

Discuss MAP packaging of meat products

Answer 108

Map is used to extend shelf life of red meat products

• For fresh meats (ground beef), package may include high oxygen (80% O2 + 20% CO2) to maintain the red myoglobin pigment on meat surface
• However, high oxygen level may lead to off colour and rancidity in cured meat and bacon. Therefore they are stored under vacuum
• Pork, poultry meat has no requirement of O2 to maintain color, so they are stored under 90% CO2 to extend shelf life to 11 days
• For cooked product, need to limit O2 to prevent oxidation so also could use vacuum packages

Question 109

What are some important considerations for MAP use with F&V?

Answer 109

For fresh fruits and vegetables- minimize respiration and senescence without causing damage to metabolic activity… loss of quality

• A typical modified gas composition for many fresh-cut fruits and vegetables: 2-5% O2, 8-12% CO2 and nitrogen – Reduces respiration rate, delay ripening and increase storage life (slow microbial growth).

– But need some oxygen present to prevent anaerobic respiration/ fermentation and related negative biochemical changes

• May need to control oxygen intake and CO2 release, as some product cannot handle excess CO2- Micro-Perforated films often used to regulate the internal atmosphere by using the natural respiration of fruits and vegetables
• It is called “equilibrium MAP or eMAP”. The targeted Modified Atmosphere develops as an equilibrium steady state composition controlled by the modified permeability of the packaging film.
• The required transfer rate of different gases through the packaging film is obtained by a properly designed microperforation pattern.

Question 110

What is the difference between MAP and controlled atmopshere storage?

Answer 110

• MAP differs from Controlled Atmosphere (CA) storage which actively monitors and changes atmosphere around product (e.g., storage of apples)
• CA utilizes low temperature storage in combination with specific concentrations of oxygen and carbon dioxide.

Ethylene may also be controlled.

Question 111

Active/ smart/ intelligent packaging are helpful how?

Answer 111

To help extend shelf life. Prevent lipid oxidation: acitve packaging containing antioxidant agents, radial scavengers, metal chelators and UV absorbers have been developed.

To monitor freshness, how long product is stored

Display information on quality. Detect temperature abuse.

Improve safety. Antimicrobial film.

Improve product convenience.

Question 112

What does a freshness label mean for meat products?

Type of active/smart packaging.

The label contains special ink that changes colour based on the amount of ammonia emitted by the meat (the older the meat, the more ammonia it releases)

When the meat is no longer suitable for sale, the ink blocks the barcode so that it cannot be scanned at the cash register.

Question 113

What could an ethylene absorber do?

Answer 113

Help keep fruits and veggies fresh long by absorbing the ethylene that would have then overripening too soon.

Question 114

How does ethylene inhibition prevent the aging process of fruits and veg?

Answer 114

Question 115

What is the secret of microwave packaging?

Answer 115

Aluminum metalized sheet at bottom of package heats to about 400 degrees C and heats to food.

“This side down” onto metal sheet.

Question 116

What does “best before” mean in comparison to “Use by”?

Answer 116

Pack date – date of production

• “Best before” or “best if used by” date. Last date of “Maximum” quality. Required when 90 days or less, also proper storage instructions must be given if not stored at room temp.Now some are trying “better if used by”
• “Use by” or “expiration date”. date no longer can guarantee nutrition info on package. (e.g. baby foods) or reduced potency (e.g. drugs)

Question 117

How long after best before date can these be consumed?

Canned goods

White flour

Answer 117

Canned good- BB is often 3 years after production, so 6-12 month more

White flour- BB 6-12 months, so 6-8 months if pantry stored after opening

Question 118

What are the role of the five senses in sensory evaluation?

Answer 118

Sight, odor, touch, taste and sound

Question 119

Which can we smell? Volatile or non-volatile compounds?

Answer 119

Aromas are volatile compounds, while we sense taste for non-volatile compounds

Question 120

How do we smell?

Answer 120

Question 121

What makes up the impression of flavour of a food?

Answer 121

Question 122

How do we smell?

Answer 122

Odorant can reach the olfactory epithelium by two route:

Orthonasal olfaction: The detection of an odor through the nostrils by sniffing or inhaling

Retronasal olfaction: The detection of an odorant when it is released from food in your mouth during chewing, exhalation or swallowing.

Some people lack or lose the ability to smell, This is called anosmia.

Difference also exist in how sensitive people are to differnt odorant. Some people are more sensative to some odorant than other.

Adaption to a specific smell also changes how we percieve a food

Question 123

How do we taste? 5 basic tastes?

Answer 123

By our tongues, sensory organ of taste/

1. Salt (NaCl)
2. Sour (lemon juice)
3. Sweet (sucrose)
4. Bitter (caffeine, alkaliods)
5. Umami (savory)- Action of trigeminal nerve’s response due to the presence of glutamate (widely prensent in meat and fermented products)

95% of what we percieve as tatse is actually smell!!!!!!!!

Question 124

What does the Trigeminal nerve do?T

Answer 124

Trigeminal nerves are responsible for sensation in the face and controlling how we chew and bite foods.

Question 125

What does supertaster mean?

Answer 125

Supertasters

Have strong good dislikes. Can detect specific ingredients in food samples. Have more intense reaction to various sensations ex) fat in food, more pain from oral irritants like capsaicin (pepper sensation).

It is thought that “supertasters” are the people with a greater number of fungiform papillae. More of these taste buds makes you a supertaster

Question 126

What is the differnce between medium tasters and non-tasters?

Answer 126

Medium tasters- tend to like all food, Are fussy about preparation. Think about food in a positive way

Non-tasters- Attentive to presentation. May prefer higher sweeness to other groups. Think of food in terms of healthfulness rather than taste. Foods sensed more as a package (health and taste and presentation all coming together).

Question 127

What is the difference between subjective tests/sensory evalutation vs objective tests?

Answer 127

Subjective tests or Sensory evaluation

• Determining preference to a particular product
• Evaluating specific flavour or taste criteria of foods
• May not be a subjective test if people are trained

Objective tests

• Laboratory methods and equipment to evaluate foods through physical and chemical tests

Question 128

What are the three sensory evaluation methods?

Answer 128

Discriminant tests

Descriptive analysis

affective/hedonic tests

Question 129

Which question would be asked for the three sesonry evaluation methods?

“are the products different”

“if the products are different, how are they different”

“What is the acceptability of a product? Is one product preferred over another?”

Answer 129

Question 130

Describe discriminant tests for sensory evaluation

Answer 130

Question 131

DEscribe descriptive analysis tests for sensory evaluation

Answer 131

Most complex and expensive of the techniques.

Most food companies have a pannel that is trained on each of their products

To train a panel takes several weeks to months

The panelists are trained to evaluate products similar to how any insurment would give a reading.

For example, a trained panel would be given a sample of grape juice and would be able to rate the level of tubrbidity, colour and viscosity. Answer on a ballot.

Lots of stats are required to gather the information from the panelists.

Question 132

Describe affective/ hedonic tests

Answer 132

Measuring the degree of liking for a food or its properties. Liking of the saltiness or sweetness?

Best done by untrained panelists.

Consumer panels- panelists should be representative of the target population for the product.

9-point scale (also referred to as the acceptance test)

Question 133

What is the importance of sensory evaluation for food companies?

Answer 133

Consumer-oriented companies have a reputation for product quality and permormance.

Consitent quality is essenial for consumer perception of quality and is the basis for brand loyalty.

Semsory evaluation is an important tool during the development of new products and its commercial launch.

There are several key steps in developing a new commercial product

Question 134

What is molecular gastronomy?

Answer 134

MOlecular gastronomy is a scientific discipline that studies the physicochemical tranformation of edible materials duing cooking and the sensory phenomena associated with eating them.

Question 135

Who said?

“The aim of Molecular Gastronomy was, is and will be forever: looking for the mechanisms of phenomena occurring during dish preparation and consumption”

Answer 135

Hervé This in his book Molecular Gastronomy

Question 136

What is the difference between molecular gastronomy and food science?

Answer 136

Molecular gastronomy is a part of food science, it is the science of domestic or restaurant cooking.

Food science is the use of physical sciecnes and engineering to study foods and understand their deterioration and the principles of food processing.

Question 137

What is the dispersed system formula?

Answer 137