We all know about body chemistry but what do we know about food chemistry. Ever wonder why you pucker when you eat a lemon or weep when you chop an onion? Food glorious food. We all love it. We all need it. It provides us with vital fuel to keep our engines going. Food is also delicious and we cannot live without it.
Yet certain foods have very different effects on our bodies. Have you ever wondered why lemons have such a bitter taste or why onions bring tears to our eyes or why asparagus makes your urine smell? Read on to discover the answers to these and other intriguing questions.
There's a chemical in asparagus called asparagusic acid which is found exclusively in this vegetable and recent studies show that as the acid is digested it produces a strong-smelling sulphurous compound which is released in urine. However, not everyone can smell the pungent after-effects. Studies show that two out of 30 people are happily oblivious to the smell of asparagus in their urine.
But those of you who can smell it will usually do so about 15-30 minutes after the asparagus is eaten because that's how quickly it starts being released in urine. Hope this answers this question.
When onions are sliced, they release an enzyme known as alliinases. These enzymes stimulate sensory neurons in the eyes, causing a stinging sensation The eyes in turn, produce tears in response to flush them out. An intact onion does no effect at all.
It's only when you damage the cell walls by cutting the onion that the unpleasant enzymes are released. Upon eating a raw onion you breath comes a close second to that of garlic in terms of bad breath odours. The action of chewing raw onions also releases the alliinase enzymes resulting in a pongy breath. Got that one right!
The food chemistry compounds called betacyanins gives beetroot its characteristic red colour and also causes "beeturia" the colouration of urine that occurs after the vegetable has been eaten. This condition is thought to affect 10-15 per cent of people.
Scientists are still uncertain as to why this is but research suggests people with a low stomach acid pH can break down the betacyanins while those with a higher acid pH cannot. The betacyanins then pass through the digestive system into the bloodstream. It's only when they reach the kidneys that they are filtered out and excreted thus giving urine a distinctive pink colour.
A family of compounds known as capsaicinoids are responsible for the heat of chillies with capsaicin being the dominant of them. When eaten they bind a receptor in the mucous membrane associated with heat and physical abrasion producing that distinctive burning sensation.
Most of us know that someone who can't seem to get enough of the hot stuff. The reason for chillies tolerance comes from repeated ingestion which depletes the receptors. You can soothe the burn with milk if need be. And the reason why milk soothes the burning sensation is that casein, a protein which envelopes the fatty capsaicin molecules, effectively washing them down the hatch.
Thailand produces some of the hottest chilli sauce you can get but you can probably purchase some at your local supermarket too.
As much as eight per cent of one lemon is made up of citric acid which is the main source of the fruit's sourness. Malic acid is present in only about five per cent of the concentration of citric acid but also contributes to the persistent sour taste.
Lemons also have high amounts of ascorbic acid (vitamin C), which at around 50 mg per 100 grammes is on par with the levels found in oranges. Vitamin C is required by the body to produce collagen (the main protein of connective tissue) and for the growth and repair of tissue.
It's also an antioxidant, which blocks some of the damage caused by free radicals. The body can't make enough vitamin C, nor can it store it. So getting enough of the vitamin is vital in maintaining good health.
While this is one of my favourite foods, and despite what many may think, chocolate won't rev up your sex-life. Phenylethylamine (Pea), a food chemistry chemical aphrodisiac, is present in relatively high concentrations in chocolate (0.4 to 6.6 microgrammes per gramme) but it's broken down when eaten which means it's unlikely to have any significant effect on your body.
Tryptophan, an essential amino acid which cannot be manufactured by the body, is also found in chocolate. This amino acid plays an important role in the synthesis of the feel-good hormone serotonin. The only problem is that it's present in such small quantities and unlikely to trigger any warm and fuzzy feelings. Sorry about that.
Please take note that the information on this site is designed for educational purposes and is intended solely for general readership. The contents herein are not intended to offer any personal medical advice or to diagnose any health issues you may have. This information is also by no means a substitute for medical care by a licensed healthcare provider. For that, you'd need to consult your medical doctor or a health care practitioner for any advice should you require prescription medication.