Torching food popular, but overcooked food is harmful
28 February 2017
The Straits Times
(Mind & Body, B14)
As anyone who has forgotten about a loaf in the oven knows, only a few minutes separate a perfect crusty baguette from an inedible charred ruin.
But how healthy are foods like grilled steak, roasted vegetables and french fries - all of which are browned to a certain degree?
Last month, the United Kingdom's Food Standards Agency launched a campaign encouraging people to Go For Gold, to raise awareness of the dangers of overcooking foods such as roast parsnips and fried potatoes.
This means aiming for a golden colour - or even lighter - when toasting, grilling, baking or frying starchy foods.
In Singapore, torching food has caught on as more chefs become interested in molecular cooking techniques, said Mr Edmund Toh, president of the Singapore Chefs Association.
"Chefs are inspired or intrigued by molecular cooking, which is a more scientific approach to food preparation," he said.
Roast the toast
What are some popular items on the menu that are known to produce harmful chemicals when they are grilled, roasted, toasted or fried?
The chemical known as acrylamide is formed when starchy, plant-based foods such as potatoes are cooked through methods like frying, baking or roasting at high temperatures of more than 120 degree C.
This includes foods such as:
• Potato chips
• French fries
• Pastries and sweet biscuits
• Roasted coffee beans
Cooking methods such as boiling or steaming, however, seem much less likely to produce this cancer-causing substance.
Char-grilling meat or seafood, on the other hand, produces chemicals called heterocyclic amines and polycyclic aromatic hydrocarbons. These chemicals can also be formed when food is pan-fried or barbecued at high temperatures, especially if it is cooked for a long time.
This includes foods such as:
•Barbecued meat, including bak kwa
•Roast meat, including roast duck and roast pork
•Char-grilled steak and seafood like stingray and prawns
Meats that are not cooked directly over a fire, but are steamed or stewed instead, tend to have less of these chemicals.
PLEASURES OF LIFE
Everything in life is a risk and one of the pleasures of life is eating good food. It's important that we keep everything in moderation.
PROFESSOR JEYAKUMAR HENRY, director of the Clinical Nutrition Research Centre, on not worrying too much but taking a sensible approach to managing risks.
"Thus, we're seeing the growing popularity of torching food before serving, which adds a charred flavour to the food."
However, the jury is still out on exactly how bad foods cooked this way are for one's health.
Experts say that what is known for certain is that browned food generally contains cancer-causing chemicals, so it is best to apply the old adage - everything in moderation.
"These foods are potentially dangerous, but so is crossing the road," said Professor Jeyakumar Henry, director of the Clinical Nutrition Research Centre.
"The fact that they contain potential carcinogens doesn't mean that you can't eat them."
The centre is a collaboration between the Singapore Institute for Clinical Sciences, the Agency for Science, Technology and Research, and the National University Health System.
What makes these foods so tasty are the chemical reactions that take place when they are cooked at high temperatures.
Prof Henry said that for starchy items like bread and potatoes, the sugars in them combine with proteins to create the enticing flavours and aromas we associate with toast or french fries.
Principal dietitian Mah Wai Yee, who works in nutrition services at Farrer Park Hospital, said: "What makes charred meat so tasty is the Maillard reaction, which rearranges the amino acids and sugars in the meat to produce the browned colour and mouth-watering smoky taste."
However, cooking carbohydrate- rich starchy foods at high temperatures results in the formation of a chemical called acrylamide.
Similarly, char-grilling meats creates compounds known as heterocyclic amines and polycyclic aromatic hydrocarbons (PAHs).
While the former is formed at high temperatures, the latter occurs when fats and juices from grilled food drip onto an open fire, Ms Mah said.
The resulting flames contain PAHs, which stick to the surface of the meat, she added.
Animal studies have shown that both these chemicals can cause cancer, with scientific evidence showing that this is likely to hold true in humans as well.
Dr Reuben Wong, a gastroenterologist at Gleneagles Hospital, said that overall, there is an increased risk of developing cancer. "In the gastro-intestinal tract, the biggest risk is with colon cancer."
That being said, there are no clear guidelines on the amount of charred food people can consume.
Ms Mah said: "Keep in mind that moderation is key. There is only a significant increase in the risk of cancer when excessive amounts are consumed."
Dr Wong added that cancer is a complex disease and its development is dependent on a person's genetic make-up, which is beyond control.
"But we can certainly control what we eat and the recommendation would be to keep one's intake of charred foods to a minimum," he said.
Prof Henry said that those who are really worried can take steps like cutting the crust off the toast before eating it.
He added that, interestingly, marinating meats in seasonings like garlic or olive oil can actually help to reduce the levels of cancer- causing substances in foods.
This is what is done at Violet Oon Satay Bar and Grill, which serves grilled foods. A spokesman said: "Research has shown that marinating meat, even for just one hour before cooking, makes the barbecued meat a healthier option.
"We do not over-char our seafood and meats. We flip the food constantly to ensure it is cooked evenly as fast as possible."
For those who are concerned, Prof Henry said they should not worry too much but simply take a sensible approach to managing risks.
"Everything in life is a risk and one of the pleasures of life is eating good food," he said. "It's important that we keep everything in moderation."