Tag Archives: Food

What Makes Food Appealing?

Posted on March 11, 2019 by | 8 comments

What’s an unappealing colour that you can think of? The first colour that I thought of was brown. To me, it looks like combination of unwanted colours and reminds me of dirt. However, this colour is highly associated with what makes our food look delicious.

Now, which of the two would look more appetizing: a pale piece of chicken (cooked by boiling in water) or chicken that has been grilled until it is golden brown in colour? I think we would agree the second one is a better choice. So what is the cause of this difference in appearance?

Boiled Chicken and Grilled Chicken

A contrast between boiled chicken and grilled chicken
(Source: Myself)

The Maillard reaction

The Maillard reaction is a chemical reaction responsible for releasing flavours and aromas of food, while also browning them. Since most people only notice the colour change, it is also commonly known as the browning reaction! The process works by rearranging amino acids (the building blocks of protein) with sugars, and only occurs in temperatures of 140°C or higher. Usually proteins are coiled-up structures but when there is enough heat, denaturation (the unfolding of amino acids) happens, which is how the sugars are able to combine with them.

The Maillard reaction occurs in many foods, but have you noticed that they don’t all have the same flavour? Coffee and popcorn both experience the same reaction, but coffee has a nutty flavour while popcorn has a biscuit flavour. This is because of the different kinds of amino acids, as each kind of amino acid releases a different scent and flavour.

 

Why don’t we just cook on high heat all the time?

Although the Maillard reaction is highly desired, we can’t just cook on high heat all the time. This is because another reaction takes place when the temperature is too high: burning. This reaction gives an unwanted bitter flavour.

However, there is a way to increase the rate of the Maillard reaction. Because water boils at 100°C, lowering the moisture content on the surface of your food will promote the Maillard reaction. This helps keep the meat at a higher temperature since it no longer limited by the temperature’s boiling point.

 

Didn’t you just describe caramelization?

Many people confuse the Maillard reaction with caramelization. Although they are both browning reactions, they are different reactions. Caramelization is the burning of sugar, and as a result, it occurs in temperatures above the Maillard reaction. The results of the two reactions look similar but the key difference is that caramelization breaks down the sugar, rather than recombine them, and does not require amino acids.

Caramelization

Caramelized sugar on ice cream
(Source: Myself)

 

The Maillard reaction is the reason why our food is so appetizing, but is under-appreciated. Many people who cook know through experience that higher heats will give a nice colour to the food, but do not know that it is actually adding flavour too.

To learn more about how the Maillard reaction works, watch this video.

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Posted in Science Communication

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Why Are There So Few Blue Fruits?

Posted on March 11, 2019 by | 7 comments

Speaking of fruits, how many kinds of blue fruits can you come up with? A recent research conducted in Xishuangbanna Tropical Botanical Garden located in Yunnan, China has shown that, amongst the over 600 species of fruits growing in the garden, only 6 types of fruits are blue. How did this come about? There are a variety of aspects that we need to look at in order to answer this question.

Blueberries
credit: https://thescooponbaking.files.wordpress.com/2015/07/fullsizerender_1.jpg

Where do colours in fruits come from?

Fruits get their colours from three main types of plant pigments: carotenoids for colours red, orange and yellow, flavonoids for blue and red, as well as chlorophyll for green colour. Due to the fact that colour red is the most common hue among the three chemicals, most fruits are red.

Colours of fruits and their reproduction

The reason why we are able to identify different colours is that the wavelengths of these colours can be perceived by a specific type of cells called cones in our eyes. Some animals see more colours than we do because they can detect a wider range of wavelengths in the nature. However, when reacting to different colours, cone cells show different levels of sensitivity to their wavelengths, and the colour blue is, unfortunately, not as visible as other colours to most animals.

Credit: https://www.quora.com/Why-is-red-on-the-right-of-the-light-spectrum-and-purple-on-the-left

Lower visibility of blue fruits leads to lower probabilities that they get spotted and eaten by animals and consequently have their seeds spread, which is an important method of reproduction for most plants. As a consequence, blue fruits can not be spread as easily and frequently as fruits with other colours such as red and orange.

However, while the colour blue gives these fruits a hard time to reproduce, there also exist some animals that are inherently colourblind. These animals spot and eat fruits randomly instead of by identifying colours, and this is also the reason why there is still a small amount of blue fruits we can find in our everyday life nowadays.

Additionally, another factor that should be taken into account is that, because it is always connected with characteristics such as danger, the colour blue can result in a loss of appetite in animals.

(video credit: https://youtu.be/l04dn8Msm-Y)

Overall, the shortage of blue fruits is due to a number of reasons. Specifically, the uneven distribution of pigments in different species of fruits and some special characteristics of the colour blue are the two main factors that account for this phenomenon to a great extend.

 

– Siqi Tao

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Posted in Biological Sciences, Science in the News

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Spicy foods: Do we eat them because we like the way they taste?

Posted on January 28, 2019 by | 4 comments

Trick question. While there are five different classes of taste, spicy isn’t one of them. Sweet, salty, bitter, sour and umami are the five basic qualities that stimulate taste receptors on our tongue and all other taste sensations arise from the different combinations. So what about spicy?

(Source: Flickr Commons)

Spicy is not a taste

We experience the sensation of spiciness not because it’s a taste but because it’s pain-inducing. Spicy foods make you feel as though your mouth is on fire even though there is no real heat in spices. The searing pain occurs because of a chemical called capsaicin present in spicy foods that activate nociceptors (pain receptors) called TRPV1 on the tongue.

Interestingly, the description of heat is more accurate than most people realize. TRPV1 normally respond to heat to alert the body for heat damage, thereby warning us when we consume literally hot drinks or foods. They respond to extreme temperatures, intense mechanical stimulation, as well as certain chemicals like capsaicin.

(Source: Wikimedia Commons (modified))

So why do we eat spicy foods?

Some of our taste preferences are innate, such as our tendencies to crave sweet and salty foods and avoid bitter and sour foods. We’re inclined to consume sugar and salt because they’re biologically useful to us and we have an aversion towards concentrated bitter and sour foods because they can be poisonous or can damage our body tissues. When it comes to spicy foods, it seems that our preferences depend on social influences.

Some people dread the runny-nosed, sweaty-faced experience while others indulge in the burn. In places like India and South America, hot peppers are an integral part of their culture and is often incorporated in daily cuisine. For example, Mexican children are introduced to chili early on through spicy candies, and by the time they’re 5-6 years old, they eat chili peppers on their own accord.

Internationally famous spicy instant noodle from Korea. The cartoon says “스트레스 해소에 직빵이닭”, which means it’ll relieve your stress. (Source: my picture)

In Korea, it’s part of their culture to eat spicy foods in an attempt to relieve stress. The rationale? The pain of eating scorchingly spicy foods distracts someone from their anxieties. Unsurprisingly, a study at the Pusan National University found that Koreans who love spicy food are more prone to stress.

In the Western world, the interest in spicy foods as demonstrated by the fire noodle challenge, Carolina Reaper challenge, etc. may have more to do with masochism than an appreciation of a burn that accompanies a meal. The love for spicy food could be an indicator of personality; a study at the University of Pennsylvania found a relationship between chili-liking and thrill/sensation-seeking in Americans.

 

Author: Olivia Wong

 

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Posted in Biological Sciences, Science Communication

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Is Taking Popular Supplements a Waste of Money?

Posted on January 21, 2019 by | 3 comments

How many dietary supplements do you take every day? According to Statistics Canada, about half of the Canadians take at least one supplement a day.  There are so many supplement products in the market today and consumers are overwhelmed with all the choices available. Are these supplements really necessary for maintaining good health? A recent review article published in the Journal of American College of Cardiology suggests otherwise.

How Supplements are made

Most supplements are synthetically made in laboratories and very few are made from naturally derived ingredients. In terms of chemistry, there is no difference found between the synthetically derived and naturally derived supplements. Most of the commercial vitamins found are made synthetically due to cost and efficiency.

Wide selection of vitamin supplements found in drugstores (source: Wikipedia)

Research on popular supplements

A team of researchers from St Michael’s Hospital and the University of Toronto claims that taking vitamin and mineral supplements have no significant effect on one’s health. The team reviewed 179 studies with single randomized trials that were published from January 2012 to October 2017. According to their review, the most common supplements taken were multivitamins, vitamin D, calcium and vitamin C. Their findings on these four common supplements reveal that there is little to no evidence in preventing cardiovascular diseases or early death. However, among all the dietary supplements that were reviewed, vitamin B9 (folic acid), and other B-vitamins such as B6 and B12 with folic acid were found to decrease the risk of stroke by 20%. On the other hand, the team was able to conclude that vitamin B3 (niacin) and antioxidants have rather a negative effect on our body, which may even lead to early death regardless of the cause.

What should we do?

Dr. David Jenkins, the lead author of the study reassures people that there is no harm in taking most of the popular supplements, however, he also adds that people should know that there are no significant benefits in taking them. He recommends that people should rely on eating a healthy and balanced diet to get their vitamins and minerals. According to his research, fruits, nuts, and whole wheat pasta were some of the foods that people should consider adding to their grocery list.

Here is a video from TED-Ed providing background information on the vitamins that were mentioned in the review. (Source: YouTube)

Tina Kwon

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Posted in Biological Sciences, Issues in Science, Science in the News

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