Functions of VIT C:
- Absorption of Iron
- Antioxidant
- Repair of tissue
- Vital for immune system function
- Repair & maintainable of cartilage/bones/teeth
- Growth to make collagen/ligaments/vessel walls
Sources of VIT C:
- Potatoes
- Melon
- Citrus fruits (oranges/lines/lemons)
- Bell peppers
- Dark green leafy veg
- Kiwi
- Tomato
Excess of VIT C:
- diarrhoea
- stomach pain
- excreted in urine
Deficiency of VIT C:
- Slows metabolism
- Dental/guns problems can develop
- Wounds are slower to heal
What is SCURVY?
Occours when levels of VIT C fall below 300mg
- Tooth loss
- Spongey gums
- Bleeding from mucus membranes
How does VIT C help absorb IRON?
- VIT C ia a reducing agent
- It reduced FERRIC IRON (non haem) into FERROUS IRON to help it be absorbed
- Blood then carries the absorbed iron and uses it to form new RBC’s
How does the AGE of F&V affect their VIT C content?
- Young F&V contain the most VIT C
- Unripened Fruit is much lower than Ripe
- Content is highest in Vegetables during periods of rapid growth e.g. - spring
How does the CONDITION of the F&V affect their VIT C content?
- Bruised F&V means cell walls are damaged which releases ASCORBIC ACID OXIDASE that destroys VIT C
- Pre bought sliced F&V will therefor have less VIT C
How does the LOCATION of the F&V affect their VIT C content?
- Enzymes are active at room temp so cool is best
- Sunlight destroys VIT C so dark is best
- Action of ASCORBIC ACID OXIDASE is slowed by refrigeration but not stopped
How does the TIME AFTER PURCHASE of F&V affect their VIT C content?
- Exposure to light & warmth accelerates VIT C loss so less time = better
- Pre packaged bags have MODIFIED ATMOSPHERES to slow down OXIDATION but once opened will deteriorate quickly
- Homemade juice to be consumed within 2/3 days
How does PREPARATION of F&V affect their VIT C content?
- MINIMAL = BEST
- Cook with kinds on
- PEALING & SOAKING reduces VIT C
- RIPPING/TEARING is best because there is less damage to cell walls
- BLUNT KNIVES are better for same reason
- Bigger pieces = less SURFACE AREA = LESS OXIDATION = less loss of VIT C
How do PROCESSING METHODS of F&V affect their vIT C content?
- PASTEURISATION of juice/milk reduced VIT C content
- Manufacturers often fortify foods to restore it
- 50% of VIT C is lost during DRYING
- CANNING looses VIT C but only a little due to the HEAT used to can
How does BLANCHING F&V affect their VIT C content?
- Looses 25% of VIT C
- Prepared F&V dropped into boiling water then cooled rapidly
- Destroys more enzymes than freezing
How does COOKING F&V affect their VIT C content?
- 75% of VIT C in green leafy veg is lost during cooking
- 25% of VIT C is lost by BOILING/ STEAMING
How does SOAKING F&V affect their VIT C content?
- VIT C = WATER SOLUBLE
- VIT C will seep out into the water resulting in loss!
How does QUICK COOKING of F&V affect their VIT C content?
- Cook for the minimum
- Use tight fitting lids on pans etc
- Mash/puree soon after to save prolonged oxidation
How does SERVING F&V QUICKLY affect their VIT C content?
- Dont keep cooked veg warm
- 25% of VIT C is lost in 15mins
How does BOILNG WATER affect the VIT C content of F&V?
- DESTROYS ASCORBIC ACID OXIDASE
- Cold water bought to the boils means enzymes are active
- GRAVY/ SOUPS/ SAUCES absorb the least
How does BICARBONATE OF SODA affect the VIT C content of F&V?
- DO NOT ADD IT
- VIT C = ACID
- BICARB = ALKALI… it destroys it!
How do different METHODS & EQUIPMENT affect the VIT C content of F&V?
- All cooking reduced VIT C
- IRON & UNLINED PANS reduce VIT C
- Pressure cooking & steaming reduces it the least!
