Lets start this scientific culinary journey by talking about the Cow. Around 30 millions years ago when the earth's moist warm climate became arid, this change led to increase in the grass lands which could grow quickly and produce a lot of seeds, during dry spells these plants were fibrous and dry. It was during this time that the horse like animals decreased and the deer like animals the ruminants survived and evolved. These animals are able to survive on less nutritious plants like dry grass and hay; there multi chambered stomach allowed for better digestion of cellulose and they are able to squeeze out the last drops of energy out of their food. The cow is part of the ruminant family, so it can utilize plant like hay and silage which are useless to humans. The cow's stomach is house to many microbes which help it to digest its cellulose rich diet. The nutrition absorbed by the digestive system of the cow are later used to manufacture milk.
Milk is amazing because its designed to be a complete food, its the sole sustaining food of the calf so its a rich source of many essential body building nutrients; specially proteins, sugar, fat and vitamin A,D,E,K and B and Calcium. All milk carries the same sort of nutrition the relative proportions vary from animal species to animal species. Milk is not rich in vitamin C or in Iron. Humans are perhaps the only creatures who drink milk after infancy but as the enzyme which is required to digest the milk sugar lactose decreases after infancy it is not surprising that most people are lactose intolerant and cannot stomach milk efficiently. Being Lactose intolerant is the norm rather than an anomaly. Most Northern Europeans underwent a genetic change thousands of years ago which allowed them to produce lactase(lactose digesting enzyme) through out life and therefore they are generally not lactose intolerant, however most people of Asian and African descent are. The best source of milks nutrition for lactose intolerant people is yogurt.
Lets talk briefly about milk chemistry. Milk is the food of the newborn so dairy animals must give birth before they can produce significant amounts of milk. The milk is produced by the mammary glands which are an astonishing biological factory with many different structures geared towards the production and storage of milk. Some components of milk come directly from the cows blood from the nutrients it digests and others like proteins, fats and sugars are assembled by the glands secretory cells. and than released into the udder. Do not be fooled by the milks bland appearance its a very complex liquid full of vitality; especially when it is fresh there is bacteria as well as white blood cells and other enzymes in it. Pasteurization decreases this vitality, more on pasteurization and homogenization next time.
Milk is slightly acidic having a pH of 6.5 to 6.7; it has the sugar lactose in it which is made up of the sugars glucose and galactose. It has two main types of proteins called caseins which make up the largest portion of the milk proteins. There are four types of casein proteins which are collectively knowns as the caseins. There are numerous other smaller water soluble proteins in milk which are left behind in the whey when the caseins coagulate in the curds and therefore are collectively known as the whey proteins; Lactoglobulin in the most common whey protein by a large margin; whey proteins make up about 20% of the total proteins by weigh.
Milk is an emulsion of butterfat globules within a water based fluid.Each fat globule is surrounded by a layer of phospholipids and proteins which help to keep the fat globules separate and not aggregate into larger molecules of butter fat grains, they also protect the fat globules from the activity of fat digesting enzymes found in the water portion of the milk. The fat soluble vitamins like A, D, K and E are found within the fat globule portion of the milk. Caseins proteins aggregate around an atom of calcium phosphate to form casein micelles; the opaque white color of milk comes from the light being deflected by the fat globules and the aggregated large casein protein particles.
In the next article I will talk more about the milks nutrition and its production. The history behind industrialization of milk and about the rise of pasteurization and homogenization. Now for the fun part
Todays recipe.
Breakfast is the most important meal of the day so before you rush out that door try this simple yet delicious and energizing smoothie.
Strawberry Banana smoothie. makes about 2 8 oz cups
1/2 cup low fat vanilla flavored yogurt
1 cup 1 or 2 % milk
2 tsp natural sugar free peanut butter
1 cup strawberries
1 banana
2 tsp whey powder (optional)
ice cubes
blend all these ingredients together and enjoy a delicious glass of wholesome goodness.
This is a complete breakfast as you are getting protein from the peanut butter, milk and whey powder and yogurt. Calcium from the milk, yogurt and whey powder. Vitamins and carbohydrates from the fruits. Antioxidants from the strawberries and instant energy from the bananas.
see you next week with more :D
References:
Biology concepts and connections by Campbell and Reece 5th edition
On food and cooking the science and lore of the kitchen by Harold McGee
Prevention- Healthy Woman
Milk- Wikipedia http://en.wikipedia.org/wiki/Milk
No comments:
Post a Comment