Process Fruit and Veg

Question 1

Fruit and Veg processing

Answer 1

Sorting
Refrigeration and freezing
Juicing
Peeling
Canning
Pickling/jamming

Question 2

Sorting Properties Fruit and Veg

Answer 2

Colour
Size
Weight
Density

Question 3

Sorting Process

Answer 3

Hopper
Vibrating Conveyor
Chute 
Photo-detector
Ejector
Product

Question 4

Sorting fruit and veg by colour

Answer 4

Strawberries - sorted into ref and green (reject green)

Apples - same idea

Question 5

Sorting fruit and veg by size

Answer 5

Conveyor belt that has rollers closer and close together

Only really works for circle object

For non circle use electronic sorter

Question 6

Refrigeration

Answer 6

Have coolant that is liquid at high pressure but gas at lower

Gas is compressed to liquid heating it up
Hot liquid is cooled to ambient temp
Then evaporated via expansion valve
Resulting in a cold gas

Question 7

Freezing

Answer 7

Needs to be -24 for most fruit and veg

Need to be frozen very rapidly - using liquid nitrogen to minimise ice crystals formation

Therefore, need larger fruit and veg to be cut into smaller uniformed pieces

Question 8

Issues with freezing

Answer 8

Does not inactivate enzymes

Causing browning and forming rancid taste during thawing

Question 9

Solution to rancid outcome of freezing

Answer 9

Blanching - deactivates enzymes

Question 10

Blanching process

Answer 10

Short duration heating of foods
Destroys enzyme activity
Food reheated rapidly to pre-determined temperature held for pre-determined temp and time
Rapidly cooled
Depends of type of fruit, size of fruit, blanching temp and method of heating

Question 11

Juicing consideration

Answer 11

Safety
Appearance and taste
Nutritional Value

Question 12

Stages of Juicing

Answer 12

Maceration
Pressing
Filtering
Stabilising

Question 13

Maceration

Answer 13

release the juice from solid fruit matrix
Crushing - breaks down call wall - brittle tissues

Heating - breaks down cell membrane

Enzyme Treatment - Breaks down viscous polymer to separate pulp to separate pulp an juice

Question 14

Pressing

Answer 14

Traditional - apple press

Continuous centrifuge

Question 15

Stabilisation

Answer 15

Prevent loss of quantity until juice is consumed Enzymes cause browning and may have microbes

Rapid consumption - no time for spoilage

Refrigerate or freeze - slows down microbial growth

Pasteurisation - Removes most microbes and enzymes, safe pH below 4.6

Concentration - reduce cost to transport

Additives - SO2 - prevent browning

Question 16

Peeling

Answer 16

Flash steam peeling - rapid heating of skin
Knife peeling - cutting away of outer layer
Abrasion peeling - coarse surface and water

Question 17

Canning

Answer 17

Used to be the most common process of storing veg for long term
Container is closed at start of heat treatment and it remains closed until use

pH higher than 4.6 - then needs to be heated for a really long time (120 degrees for 20mins)

High temperature is achieved using steam

Destroys taste compound and vitamins the longer it is heated
Water and steam promote heat transfer
Speed of movement through equipment determines rate of heating and cooling
Heating and cooling take longer for larger cans

Question 18

Pickling / Jamming

Answer 18

High concentration of small molecules will reduce water activity and inhibit growth of micro-organisms
Acids can be added to ensure pH<4.6
Combination of acids with sugar or salt improves protection
Combine with heat treatment to reduce microbial load

Question 19

Nutritional effect of juice

Answer 19

Vitamin C, Polyphenols, Proteins are degraded or polymerised

Question 20

Freezing nutritional effect

Answer 20

Blanching leads to water soluble compounds being lost, less is lost with steam

If no blanching then lipids turn rancid

Question 21

Canning nutritional effect

Answer 21

Vitamin C and other vitamins degraded by heat

Question 22

Pickling nutritional effect

Answer 22

Beta-carotene degrade if pH ,3.5