5.2 Food Preparation

Question 1

Which nutrients decrease with cooking?

Answer 1

Water-soluble nutrients like B vitamins and vitamin C

Question 2

Which nutrients are increased at moderate temperatures?

Answer 2

Nutrients such as vitamins A, D, E, K are released from the thick cell wall

Question 3

What antioxidant found in tomatoes increases with cooking?

Answer 3

Lycopene (of particular therapeutic benefit in prostate cancer)

Pureeing tomatoes also increases lycopene content.

Question 4

Why is boiling not recommended?

Answer 4

• Boiling greatly reduces nutrient content, in particular B vitamins, vitamin C, potassium and plant compounds such as chlorophyll
• Flavour, colour and texture are also altered
• Drink the water or use it as a base for soups

Question 5

Why is steaming more effective?

Answer 5

• Steaming minimizes nutrient losses while taste and colour are retained
• The longer the exposure to air, heat and water, the greater the nutrient losses

Question 6

What are the dangers of high heat when cooking meat?

Answer 6

• Heterocyclic amines are produced (linked with increased risk for cancer, especially colon cancer)
• Polycyclic aromatic hydrocarbons (carcinogenic) if fat from the meat drips and begins to smoke
• Inflammatory compounds called advanced glycation end products (AGEs, linked to diabetes, Alzheimer’s, atherosclerosis and kidney disease)

Question 7

What happens when oils are heated to high temperatures?

Answer 7

• Oxidation of fatty acids
• Results in free radical damage in the body

Question 8

How can dangers be reduced?

Answer 8

• Use smaller pieces (kebabs) as they cook faster at a lower temperature.
• Marinate meat and veggies in antioxidant spices such as turmeric and rosemary before cooking lowers carcinogenic compounds.

Question 9

What is Steam sautéing?

Answer 9

Sauté foods in water adding a small amount of oil at the end for taste

Question 10

What is the key consideration when cooking?

Answer 10

Keep the temperature low
Maintain the water content of the foods

Question 11

What are considerations when buying/storing oils?

Answer 11

• Use cold-pressed oils, stored in dark, glass bottles
• Store in a cool dark place or in the fridge.
• Heat, light and air cause oils to slowly go rancid - add a drop of Vit E to help preserve
• When cooking with oils that contain unsaturated fatty acids (and hence have doubled bonds in their chemical structure), they are prone to oxidation which leads to free radical damage and inflammation
• Ingesting or inhaling oxidized oils is associated with atherosclerosis and DNA damage (i.e. cancer)

Question 12

What are considerations when cooking with oils?

Answer 12

• Oils with unsaturated* fatty acids are prone to oxidation which leads to free radical damage and inflammation
• Monounsaturated (e.g olive oil) oxidise less easily than polyunsaturated oils (sunflower, sesame, fish oils)
• Ingesting or inhaling oxidized oils is associated with atherosclerosis and DNA damage (i.e. cancer)

*Double bonds in their chemical structure

Question 13

When is the best time to add oils in cooking?

Answer 13

After cooking the food, to avoid heating them

Question 14

Which oils can be used if heating is necessary?

Answer 14

• Monounsaturated fats such as olive, macadamia and avocado oils
• Extra virgin olive oil can be heated to 180 - 200°C
• Saturated fats such as coconut oil are stable with heat and barely oxidize at all.

Question 15

What oils can be used at Medium temperature cooking

Steam sautéing/Sautéing/Lower temperature roasting (e.g. 150°C)

Answer 15

• Virgin olive oil
• Coconut oil
• Avocado oil
• Butter (from grass-fed cows)

Question 16

What oils can be used at higher temperature cooking (180°C+)

Frying/roasting/grilling/baking

Answer 16

• Avocado oil
• Coconut oil
• Ghee or clarified butter

Question 17

What oils should be avoided?

Answer 17

• Soya-bean oil: has a short shelf life and is often treated with hydrogen gas so it becomes trans-fats
• Corn oil: generally extensively processed and refined. Predominantly GM in the US
• Canola, palm and vegetable oils (unless cold-pressed) are highly processed and exposed to high heat to create them

Question 18

What are phytates?

Answer 18

• Naturally-occurring compounds in grains, legumes, seeds and nuts. They bind to some minerals (iron, zinc, calcium) and slow or prevent their absorption in the GI tract
• Most people consume sufficient minerals. The small amounts that becomes bound to phytic acid will not lead to a deficiency
• Phytates are antioxidants and do have health benefits

Question 19

What happens when nuts and seeds are soaked?

Answer 19

The germination process is activated
* Lowers starches
* Releases nutrients
* Increases enzyme actions which helps to digests more nutrients

Use raw, not roasted!

Question 20

Why should beans be soaked?

Answer 20

• Dried beans contain varying levels of fermentable oligosaccharides, which can cause intestinal discomfort and flatulence

Question 21

What are some examples of Fermented Foods?

Answer 21

• Kimchi (Korean fermented cabbage, onion, garlic, carrots)
• Sauerkraut (fermented cabbage)
• Kombucha (fermented tea and mushroom drink)
• Kefir (fermented milk, water or coconut)
• Yoghurt (should be organic, grass-fed, full fat, plain); coconut yoghurt
• Sourdough bread (not a commercial variety)
  Make sure there are no added ingredients such as sugars, preservatives and fruit ‘flavourings’.

Question 22

How can phytates be reduced in nuts, seeds, grains and legumes?

Answer 22

By soaking in water overnight

Question 23

What methods can be used to soak Beans?

Answer 23

• Overnight method: place beans in a large bowl and fill with water until water is at least 2 inches above the beans, leave overnight.
• Quick method: boil beans in water for 2 to 3 minutes. Remove from heat, cover and let soak (1 - 4 hours).

After soaking, drain and rinse. Place in pots with water; cook until tender