Hello! In my last post, I will discuss about Molecular Gastronomy and the Future of Food. Additionally, I will be wrapping up this post with my final thoughts on this module 🙂

Molecular Gastronomy

In my previous post, I briefly mentioned about the term –  Molecular Gastronomy, where it incorporates Science and new techniques in the preparation, transformation and artistic presentation of food. Since there are different aspects of Molecular Gastronomy, I will be focusing on Emulsification.

Do you know what chocolate, milk, butter and ice cream have in common? All of them are emulsions!! In molecular gastronomy, emulsification is the technique used to incorporate and stabilise air bubbles in a liquid mixture.

Do you remember how I mentioned whisking  a mixture vigorously allows air bubbles to be introduced into the emulsion? (whisking egg white to produce foam -a step in making souffle pancake). However, this method of generating air bubbles is highly unstable and the air can escape in a relatively short time!

As such, I have learnt that using an emulsifier can  help to better stabilise the mixture. Some common emulsifiers used are egg, starch and gelatin. Besides these common ones, soy lecithin can be used as well. It is more commonly referred as a surfactant, where the molecules can act as a barrier between water and air.  By doing so, it reduces the tension between the water and air surface, which further stabilises the air and foam.

There are also other factors that can affect the success of generating foam. In fact, foam containing a larger number of small air bubbles is generally more stable than one formed using a small number of large bubbles. As such, using a hand mixer, a more powerful machine, is able to create more and smaller air bubbles, as compared to foam made with a whisk.  A large amount of bubbles dispersed in the liquid also increases the viscosity of solution, which gives foams their creaminess.

Future of Food

The drastic changes in climate, coupled with global warming has inevitably led to food insecurity. The decrease in crop yield due to climate change has threatened the availability of food. This also ultimately results in a rise of food prices, causing an increased risk of food insecurity. As such, there are many new discoveries that explores innovation to create new solutions for these problems.

Based on the readings, the one that caught my attention was “The Meat of Affliction” article. I am surprised as to how this article mentions the consumption of insects  to replace the traditional livestock as an alternative source of protein. Interestingly, the article mentions how insects have lower environmental footprint and possess protein rich nutrients. While consuming insects may be more sustainable in terms of lowering CO2 emissions, I feel that it is not viable due to the appealing nature of insects. Would you want to consume insects as part of your daily diet? I doubt so.

Another interesting article is the “Recent developments in 3D food printing”.  Basically, 3D food printing involves the customization of food according to individual needs and preferences. It is an environmentally-friendly approach as it can help to convert alternative ingredients such as proteins from algae, insects or beet leaves into tasty products. However, this approach has its disadvantageous. It is not easy, and in fact expensive. Furthermore, this method might not be widely accepted due to physiological barriers.

Final thoughts

I definitely have no regrets taking this module in my last study semester!! 🙂 I am fascinated to learn more about Science with regards to food, where topics like Molecular Gastronomy, Baking, Cooking were further explored. The interactive and hands-on workshops also made this module way less mundane compared to other modules. Through the workshops, I am so glad to be able to have the opportunity to learn more and even make my own Chocolate Mousse / Sorbet / Pancake / Kombucha!! And also the Coffee workshop that allowed me to better appreciate the different types of Coffee.

Few weeks back, I attended a Molecular Gastronomy workshop conducted by Dr. Linda. Molecular gastronomy is a movement that incorporates Science and new techniques in the preparation, transformation and artistic presentation of food. It is the study of molecules, especially on how the physical and chemical transformation of ingredients that occur in cooking can affect the overall taste/texture of food.

Figure 1. Certain processes in food (taken from workshop slides)

I was introduced to certain terms regarding food processes (Figure 1). It was indeed fascinating to know how each of the different ingredients has an important role to play in food preparation.

In this workshop, there was also hands-on activities which involved making Chocolate Mousse and Ribena Sorbet!

Chocolate Chantilly 

The steps to making Chocolate Chantilly, also termed as Mousse, is relatively simple. It involves melting 100g of chocolate into 85mL of hot water, followed by stirring it vigorously while letting the mixture bowl sit on a bed of ice. The end result should be give an airy and creamy texture.

So what is the science behind making Chantilly?

When hot water is added to the chocolate, an oil-in-water emulsion is formed. The hot water acts as the continuous phase, whereas the melted chocolate (oil cocoa fat) is the dispersed phase. By whisking the mixture vigorously, air bubbles is introduced into the emulsion and the oil molecules subsequently coats the air bubbles. Then, cooling the mixture in an ice bath allows the oil molecules to solidify into fat crystals and further trap the air molecules. This can be observed by an increase in viscosity of the chocolate mixture, and subsequently forming the airy creamy texture.

Based on these simple steps, it can be seen how simple ingredients could work together to create an airy and creamy chocolatey chantilly! No other ingredients, such as egg white, which normally gives food a fluffier texture due to the formation of foam is required 🙂

     Figure 2.  Chocolate bar used (left) and my group’s failed Chantilly (right)

My group’s Chocolate Chantilly definitely did not turn out how it should be – airy and creamy 🙁 Instead, what we obtained was just a watery chocolate texture… Despite whisking long enough, the mixture did not turn viscous. This could be attributed by type of chocolate used. As the chocolate we used contained 0% sugar, it could have attributed to this undesirable outcome.

Ribena Sorbet

Unlike ice cream making which involves the use of milk to give that additional creamy texture, sorbet making does not involve the use of milk. Hence, it is much easier to prepare, which only requires 2 main ingredients. The fruit flavour (in this case Ribena) and dry ice (solid carbon dioxide).

Figure 3. Ribena sorbet

Crushing the dry ice into smaller pieces and pouring the Ribena juice, followed by intense mixing, Sorbet is produced 🙂

While making the sorbet, it is important to crush the dry ice into smaller pieces so that the resultant sorbet has a better mouthfeel, rather than larger crystals that will feel coarser and grittier in the mouth.

Another observation made is that the sorbet tasted slightly fizzy, which is attributed by the dry ice. As the dry ice would sublime into carbon dioxide gas, it causes the Ribena juice to be saturated with carbon dioxide bubbles and thus, provides that fizzy taste.

And that’s it, another fun and fulfilling workshop which involves food and science!

Readings

Through the readings, I learnt about the two different basic methods of cooking:

1) Dry heat cooking:

Some examples of dry-heat techniques involve roasting, stir-frying, and deep-frying. This method involves the circulation of hot air (radiation) or direct contact to fat (conduction) to transfer heat. Radiation is the transfer of energy with the help of electromagnetic waves, whereas conduction is thermal energy exchanged from one particle to another through collision.

2) Moist heat cooking

Some examples of moist-heat techniques involve braising, boiling and steaming. This method uses water, liquid or steam to transfer heat to food via convection, which involves the movement of fluids.

Another two important concepts I have learnt is Caramelization and Maillard Reaction. Caramelisation is a type of non-enzymatic browning reaction, which involves pyrolysis of certain sugars at high temperature. It is also known as the oxidation of sugars, which results in nutty flavour (initially sweet to some bitterness and acidity flavour) and brown colour.

On the other hand, Maillard reaction is also a form of non-enzymatic browning, but it is a chemical reaction which involves an amino acid and reducing sugar. Although Maillard reaction may be desirable as it gives browned food its distinctive flavour such as bread, it often results in a loss of protein nutritional value due to reaction of essential amino acids and sugar. Hence, to minimize Maillard reaction, temperature can be lowered as high temperature leads to more significant Maillard browning. Also, a reduction in the concentration of sugar can be used to slow down Maillard reaction.

Let’s get cooking!

This week, I attended a self-directed Pancake workshop. My group was tasked to make Japanese Souffle Pancakes. Compared to traditional Western pancakes, Japanese Souffle pancakes are lighter and fluffier in texture. You may be wondering, why is this so? Read on to find out! 😊

Figure 1. List of ingredients used

Through this workshop, I was able to further appreciate the role of certain ingredients after having read the readings.

An important ingredient in making pancakes is the use of baking powder. Baking powder is a leavening agent, which is often used to increase the volume and lighten the texture of food. It works by releasing carbon dioxide gas into the batter through an acid-base reaction, which causes bubbles in it to expand and hence, leavens the mixture.

But what makes Japanese souffle pancakes fluffier than Western pancakes? It is the use of egg whites and sugar to make meringue!! Fascinating enough, whipping egg white forms foam. Foam is produced by trapping millions of gas bubbles in the whipped egg white, which allows the final Japanese souffle pancakes to have a lighter mouthfeel.

Figure 2. How an actual Japanese souffle pancake should look like (left) vs the actual product made by my group (right)

However, our Japanese souffle pancake did not turn out the way it should be ☹. As we were not provided with a hand mixer to whisk the egg whites, we had to do it manually. Thus, we were unable to form a nice stiff peak of foam while whisking the egg white, resulting in a much less fluffy pancake. Additionally, it can be seen that the pancake made has a slight brown colour, which is attributed by Maillard Reaction (as explained earlier on).

Figure 3. Group shot!

Despite the failed attempt in making fluffy Japanese souffle pancake, it  still tasted good! I would definitely try out this recipe again at home, but this time ensuring that a good meringue is formed to give that desired fluffy and light texture pancake.

Readings

In this topic, I was introduced to Brewing and Fermentation. Though the readings were quite long, they were interesting as it has allowed me to gain a wider exposure on these two particular aspects.

Brewing

In the Coffee Workshop which I attended a few weeks back, I was introduced briefly to the different parameters of brewing, such as temperature, pressure, grind size, etc. In one of the readings on Brewing, these concepts were further reinforced, where I learnt the parameters of brewing in greater detail.

One interesting thing I came across was that long cup coffees tend to be both stronger and bitter, which is due to over extraction that favors the extraction of less soluble, bitter and astringent compounds. This changes the sensory profile, where it moves from sweet acidic one, to bitter-harsh one. To prevent over extraction, filtration should be stopped after a planned time and hot water can be added to the brew instead of waiting for all the water to pass through the grounds.

Fermentation

To put it simply, fermentation is a biological process carried out by microorganisms, which can transform many raw materials into flavors. Generally, it involves the microbial conversion of glucose (carbohydrate) into ethanol and carbon dioxide.

For a good fermentation process, temperature is important. As temperature increases, fermentation rate accelerates. With increased fermentation rate, aromatic compounds are produced because the metabolic intermediates are excreted from yeast. Warm fermentation often leads to a fruity aroma. However, if the fermentation temperature gets too hot, desirable fruit aromatics will be blown off, and the yeast will become too stress, which inhibits yeast activity. Hence, the optimal temperature for fermentation is usually room temperature!

Fermentation Workshop

In Week 4, I attended a fermentation workshop conducted by Ding Jie, the founder of Starter Culture. I was taught on certain basic concepts regarding fermentation, which mainly focuses on Kombucha. This workshop was definitely enjoyable as I got to do my own Kombucha fermentation!!

So what is Kombucha exactly? Well, kombucha is a fermented, slightly alcoholic, sweetened black or green tea drink. It is consumed because of its supposed health benefits. Specifically, for kombucha fermentation, lactic acid bacteria (LAB) converts sugar to lactic acid, and acetic acid bacteria (AAB) converts sugars to acetic acid and cellulose. Yeast was added to convert sugar to ethanol.

We were provided with both a jar and a bottle to observe for fermentation.

The jar was covered with a kitchen towel (breathable material) to allow aerobic, primary fermentation to take place. This allows oxygen to enter so that fermentation can take place.  A layer of white substance was seen forming on the surface of the tea after 5 days. This layer is known as the cellulose pellicle, which is a bacteria that forms during the fermentation process.

On the other hand, anaerobic, secondary fermentation occurred in the bottle. Carbonation drops were added to make the fermented kombucha fizzy in the airtight bottle. When I first tried the fermented kombucha from the bottle, it tasted sweet and slightly fizzy. After leaving it to stand at room temperature for 5 days, fumes were seen when I opened the bottle, due to build up pressure! Moreover, it tasted much more sour and fizzy.  Having left it longer to allow the brew to continue its fermentation process, the more sour and tart it gets!

In Weeks 1 and 2, the textbook readings and videos introduce certain chemistry concepts in food and drinks, such as the major compounds found in food, as well as their basic chemical and physical properties. As a Chemistry major, understanding the concepts of pH, phase diagrams (triple point, supercritical fluid), chemical bonds, water hardness, etc were relatively easy. These concepts further emphasised what I have learnt so far in my undergraduate years, but in food applications.

In one of the videos, I learnt a few interesting science-based cooking techniques/tricks to make tastier meals. An example would be the use of beer instead of yeast to make bread. Interesting enough, I definitely did not know that beer has such a useful purpose! This is only possible as both beer and bread share the same fermentation step. In bread making, fermentation is where yeast consumes sugar and releases both carbon dioxide and alcohol as waste products. However, using beer alone will result in denser bread, which is not desired. To rectify, self-rising flour, which contains baking powder and salt can be used. The sodium bicarbonate present reacts with acids in dough to create additional bubbles of carbon dioxide, giving a more fluffy bread!

Coffee Brewing Workshop by The Coffee Roaster

Two weeks ago, I attended an interesting and informative Coffee Brewing Workshop (16 Jan). I learnt a lot about coffee, such as its origin, the different types of coffee (espresso, long black, americano, latte, etc.) and the different parameters in brewing coffee (brew ratio, grind size, temperature, pressure, etc.).

Truthfully speaking, coffee plays quite a significant part in my life. I used to rely and only drink 3-in-1 instant coffee to keep myself awake for classes. However now, I have switched and grew fondly of both Frappuccino and Latte 😊

Through this workshop, the most interesting segment I have learnt is understanding the different types of coffee (espresso, long black, americano, flat white, cappuccino, latte, etc.) which I wasn’t well aware of. Unlike black coffee (espresso, long black, americano), white coffee (flat white, cappuccino, latte) involves the use of milk/cream to enhance the flavour of black coffee.

Another fascinating takeaway is the difference between flat white, cappuccino and latte, categorise by their different ratio of expresso, steamed milk, and foam. Flat white introduces no foam, whereas cappuccino introduces a thick layer of foam, and latte has a relatively thinner layer of foam.

So how does foam forms? Interestingly, the foam found at the top of coffee is known as Crema, which can be explained by Science! Crema is a golden layer found on the top of espresso, which is formed during emulsification. During espresso making process, hot water pumped at great pressures pushes oil from the coffee beans into the liquid, forming air bubbles. So, the next time when I order white coffee, I will try out both cappuccino and flat white, other than my usual order of latte, to see how foam will affect the taste of white coffee 😊

Class photo taken during Coffee Brewing Workshop

Looking forward to the next workshop: Fermentation!