WATER IN FOOD LJW2009 BUA/HAUC NOF/F&FM AS A FOOD COMPONENT USE IN FOOD PROCESSING AS A NUTRIENT FOR LIFE

PROPERTIES OF WATER  naturally occurring in 3 states  unchanged when utilised within body  high melting/boiling points  excellent conductor  unique configuration  no smell/taste/colour

ROLE IN NUTRITION  CONTINUOUS LOSS FROM BODY ; Urine – 1300 mls/day Faeces – 60 mls/day Lungs (via respiration) – 300 mls/day Skin (via perspiration) – 920 mls/day

ROLE IN NUTRITION cont  SUPPLY IS FROM A VARIETY OF SOURCES ; Food – 1120mls/day Drink – 1180 mls/day Oxidation (metabolism of food) – 280mls What do you understand by the recommendations to consume 2l /day?

‘is thirst a reliable indicator of needs?’  Under normal circumstances intakes = losses SELF REGULATING  DEHYDRATION – losses exceeding 10% of body water  What causes dehydration ? deprivation disease thermal extreme – heat OR cold

Water in the human body

PROPERTIES OF WATER WITHIN THE BODY  Universal solvent – electrovalent covalent  Biochemical reactions  Transport & absorption  Homeostasis  Evaporation /heat loss  Excretion  Protection  Lubrication

WATER IN FOOD  The presence of water in food can be considered in 2 ways ; (i) Moisture percentage – by composition (ii) Water Activity – its availability for chemical/physical reactions within the food and microbial activity

WATER ACTIVITY  Expressed as a value on a scale from 1.00 down to 0.00  Pure water has a Aw of 1.00  Vegetable oil has an Aw of 0.00  The higher the value – the more water is available ; for reactions for microbial growth

WATER ACTIVITY ( Aw) cont Aw % water Fresh meat % Bread % Rice % Sugar % Vegetable Oil

WATER IN FOOD PROCESSING- FREEZING DRYING SALTING/SMOKING MAP All remove or reduce the availability of water

Water : food interactions  Aids mixing  Aids heat transfer  Acts as a lubricant Water also – dissolves effects boiling & freezing points forms gels can be ‘bound’ into foods

‘TAP’ or ‘BOTTLED’??  Is any water pure ? Dissolved gases + salts ( minerals) Impurities  Is tap water clean ? EU regulated Filtered Chlorinated ( 0.5ppm) Fluorinated ( 1ppm)

BOTTLED MINERAL WATERS  Sterilised with Ozone ( 1-2ppm)  Dissolved salts determine hardness  Sparkling (natural or artificial carbonation) or still  Added flavours or fortification ( eg calcium)

Bottled Water - definitions Spring Water can be collected only at the spring and must be bottled at source. May be treated to meet hygiene standards Mineral Water contains more than 250 ppm of total dissolved solids which are present at the point of emergence from the source. No minerals can be added to this water nor can it be drawn from a municipal source. In Europe, any recognized spring water with minerals can be called mineral water. May not be treated –only filtered Sparkling Water contains the same amount of carbon dioxide that it had when it was drawn from the source.

Vital fluids - drinks in our diet + culture Early settlement/ development determined by availability of water - is this becoming an issue again ?? How certain are we of the provision /sustainability of water for drinking,food production, and sanitation ??

Nature of Food should also consider the wider aspects of liquids in our diet and culture Think about - Food preservation – fermentation of fruit and cereals produced wine + beers Nutrition – carbonated + alcoholic beverages can make substantial contributions ( with +ve and –ve effects) Food culture – the role of drinks is often a key marker/ element

History of the world in five glasses !! Brewing beers made water safe to drink Wine is a key element in culture + religion Distilled spirits (rum, whisky + brandy) played a large part in global trade + exploration Coffee + tea were associated with commercial, intellectual and political developments Coca cola can be seen as the emblem of a global market place,the USA as a super power and consumer capitalism

Do we encourage the drinking of waters ? What would be the important issues ??