Food Review 2

Eating more than is needed can lead to obesity. This is associated with cancer, type 2 diabetes and CHD Body mass index is a way of determining whether a person is overweight

BMI = body mass in kg / (height in m)2 BMI

Category

Less than 18.5

Underweight

18.5-24.9

Acceptable

25-29.9

Overweight

30-34.9

Obese (class 1) Obese (class 2) Severely obese (class 3)

35-35.9 Over 40

Remember mass in kg here England 2007 17% men and 21% of women estimated BMI more than 30

-Risk of heart disease is increased if there is: A concentration of cholesterol in the blood greater than 5 mmol dm-3 A high concentration of LDLs (bad!) more than 3mmol dm-3 A low concentration of HDLS (good fat!) less than 1mmol dm-3 Low ratio of HDLs to LDLs. Ratio should be 4:1 Remember: Atherosclerosis is build up of plaques in the artery walls LDLs deposit cholesterol which accumulates with fatty acids, calcium salts and fibrous tissue

Autotroph Heterotroph Selective breeding Artificial selection Fertilisers Mycoprotein Food spoilage Pasteurisation Irradiation Sterilisation

Ingredients Rice, Sugar, Wheat (Wholewheat, Wheat Flour), Vanilla Flavour Clusters (10%) (Rolled Oats, Rice, Wheat Flour, Sugar, Vegetable Oil, Milk Whey Powder, Wheat Gluten, Defatted Wheatgerm, Skimmed Milk Powder, Barley Malt Extract, Salt, Glucose Syrup, Starch, Emulsifier {Soy Lecithin}, Glazing Agent {Gum Arabic}, Flavourings), Wheat Gluten, Defatted Wheatgerm, Skimmed Milk Powder, Freeze Dried Fruit(3%)(Cranberry, Raspberry), Salt, Barley Malt Flavouring, Vitamin C, Niacin, Iron, Vitamin B6, Riboflavin (B2), Thiamin (B1), Folic Acid, Vitamin B12.

Selective breeding Humans often want to develop a new variety (or breed) of plant or animal that has all the characteristics that they want. This is usually done to benefit us in some way.

Crops

Livestock

Pets

Garden plants

Dairy farmer

Characteristic

1. Select the best cow

3. Mate 2. Select the best bull

4. Select the best offspring and mate again

Crop Plants

Livestock

-Increased yield of grain, roots, tubers (potatoes), etc -Resistance to pests e.g. insects -Resistance to microbes -Better quality e.g. nutritional value and flavour

-Increased yield of meat, milk and eggs -Fast growing breeds -Resistance to disease -Better quality meat

Nitrogen as nitrates or ammonium ions – makes amino acids Magnesium – chlorophyll Potassium – Enzyme cofactors and for guard cells to open stomata Phosphate – Makes DNA, RNA and coenzymes for respiration -Natural fertiliser -Artificial e.g. NPK Pesticides 10.Herbicides – Kill weeds that complete with germinating crop 11.Fungicides – On crops that may grow fungi dependent upon weather 12.Insecticides – Insect levels may cause an economic loss Or: 15.Crop Rotation 16.Biological control 17.Antibiotics – Added to animal feed to reduce activity of bacteria in gut so more food available for digestion (banned in EU but still in USA)

Yogurt Cheese Beer Wine Bread Quorn QUORN Fusarium venenatum strain PTA-2684 is a soil mould fungus has been developed and used since 1985 as a meat substitute

Advantages

Disadvantages

Microbes grow rapidly High yields Factories use less land and can be set up anywhere Use waste material as substrate No ethical issues Low fat or no fat foods

Microbes subject to infection by viruses (bacteriophages) Fermenters can get contaminated Customer resistance Purification and processing can be expensive

-Mould, fungi, discolouration, softening, unpleasant odour -Extreme = vats of grain infected with fungus Aspergillus which produces carcinogenic toxins called aflotoxins Method

Example

Principle

Salting

Salted cod

Pickling

Sauerkraut

Removes water by osmosis Gives low pH so

Heat treatment

Milk, wine

enzymes in microbes denatured Pasteurisation and

Freezing

Meat

UHT Water frozen so not available for microbes

Irradiation

Fruit, prawns

X-rays/gamma rays kill bacteria and moulds by breaking bonds in proteins and DNA