Friday, 26 March 2010

"And finally, Monsieur, a wafer-thin mint." *

Update (28/03/2010): I 've just read on the BBC News (again) that the Food Standards Agency in the UK is asking food manufacturers to start making available smaller packages of the unhealthy snacks, as well as to cut saturated fat in foods like biscuits and cakes.

I was really intrigued by the BBC News article regarding the change in portion sizes depicted in the Last Supper through time. The article was saying that, with time, the food present on the Last Supper table was getting more and that the portion sizes grew larger!

I always suspected that we eat more than once people used to. And I could imagine that the everyday visual stimuli (read: advertisements) would point to that directions. But I wouldn't easily say that even classical, artistic themes, such as the Last Supper, would be affected by what we tend to do in our everyday lives.

The evolution of the portion size is getting more and more into focus. People seem less skilled in properly controlling the amount of nutrients they take. And that is understandable. Food was - and still is - a human need. But it's also an element of social life. Not to mention that a range of disorders can affect the food intake in terms of quality and quantity.

One of the trends in the food industry - consumers interface, is the increase in the amount of information food producers make available to consumers. Food labelling regulations in Europe do not require the provision of nutritional information, unless a nutrition or health claim is made on the food label. However, more an more often, such information is featured on packaged food, while catering businesses have begun adding such information next to their dishes in the menu or on the packages of take-away food. According to the Examiner, the new health bill in the United States may make displaying calorie content compulsory for restaurants, which is certainly an interesting development.

Consumers have - at times - expressed confusion over the various food labelling schemes. In Europe, the GDA nutrition labelling scheme is gaining popularity amongst food producers. The GDA scheme informs the consumer on one or more nutritional attributes of a food product, refer to the absolute and relative content of a portion of the said foodstuff, taking into consideration the Guideline Daily Amount for that nutrient. Most implementations of the GDA scheme include reference to calories, sugars, fat, saturates and sodium. However, the list is being enriched with additional elements.

Part of the debate at the food industry stakeholders level is what to do with the portion size. There is no strict, formal definition of "portion size". Every food producer can choose what they judge as appropriate for their product. But critics argue that setting on the label of an 100g-pack of crisps the portion size to 40g is, simply, not realistic. I couldn't agree more. Yes, it might be prudent to eat only 40g of crisps but come on.... No, I'm not trying to hold responsible the food companies for my extra kilos of body weight. But I, too, support that "portion size" in everyday life is defined more in terms of convenience rather that nutritional content. In other words, the portion is the bag of crisps and not the amount that I should consume based on the nutritional profile of the said crisps.

It is a fact that people can make considerable error in fixing a portion for them. Even the size of the plate the food is put onto may play an effect on how much people will consume; the Small Plate Movement is encouraging people who want to loose weight to use smaller plates.

The debate on portion sizes is certainly no mere philosophical discussion. There are implications at many levels. Risk assessment, for instance, is done on the assumption of a certain portion size (although, depending on the case, a "large portion" may be taken into consideration) - see here for an example of how risk assessment is made. Assuming a smaller portion size may lead to a lower projected risk.

Indications that consumers adopt a one-package=1 portion approach in some cases, causes nutritional concerns, especially when the foods in question can contribute to a higher calorie intake or feature a high glyceamic index. In the case of people with existing disorders such as diabetes or cardiovascular problems the issue escalates to health concerns.

And then, there is the possible impact on food prices and the environment because of the need for additional packaging material (also, higher transport cost per food unit, etc.).

However, I admit, the portion size alone is no panacea in the nutritional problems of - mostly - the western world. Surely, in the good nutrition game, consumer education, possibly from the younger ages, cannot be ignored. After all, eating well is much easier when it becomes a largely practiced habit.

* A line from a rather disturbing scene featuring the dialog between Maitre D and Mr. Creosote from the Monty Python's The Meaning of Life.

Monday, 15 March 2010

The science in the (kitchen) cupboard

Photo of flying pop-corn

It is interesting that when people want to describe something complex they refer to it as "rocket science". On those grounds, I guess introducing oneself as a "rocket scientist" (or as an aerospace engineer) in most social occasions would cause plenty of heads to turn to oneself. Now, I wonder if introducing oneself as a "food scientist" would have the same effect.....

I admit - I've never tried it. But my gut feeling is that "food science" scores really low on the coolness scale most people maintain. And that is totally unfair!

Food science is not an isolated island in the sea of knowledge. Instead, it would be better described as a large group of islands: food science is about chemistry, physics and biology applied onto systems of considerable complexity. I know. It doesn't sound convincing. So let me give you a couple of simple examples:

Example 1: Pop-corn physics. You know the story: You take dry corn seeds; you throw them in a saucepan with a bit of oil; you warm the saucepan; after a while the corn seeds violently explode into yummy white-ish flakes. So what has happened? Well, basically, two things have happened: Firstly, the water inside the seed turned into steam, which, with when heated up to about 170-200 oC, it raises the pressure inside the corn seed to very high levels, until the seed hull finally breaks with a explosion. Secondly, the starch inside the corn seed changes it structure to a higher volume "jelly" form. When the seeds explode, the water steam - starch mixture breaks loose and rapidly expands; at the same time, the steam escapes to the atmosphere leaving back the familiar, starch-made, foamy structure that we call pop-corn.

Example 2: Corn flour physics. Corn flour is a rather popular ingredient. In cooking, water-dispersed corn flour often functions as a thickening agent, which, when warm is thin-flowing, but when it gets colder it assumes a jelly-like behaviour. Kids are a bit more familiar with the corn flour slime, which, is unarguably considerably more fun: Just slowly start adding corn flour to a bowl with a bit of water, while stirring to ensure homogeneity; once you reach equal amounts of water and corn flour, the mix will become thicker; keep adding corn flour slowly and you will reach a point (which depends on the type of corn flour you use and the temperature), where the mix will be changing to a "solid" form under rapid stirring and melting back to the liquid form when the stirring stops.

Why that strange behaviour? Well, corn flour contains a lot of corn starch. Starch is carbohydrate molecule, comprised by lots of glucose molecules linked together, forming a long chain. Starch chains also feature smaller glucose chains (branches) attached onto the main chain. When in solution, the neighbouring starch chains can interact with each other. At a certain starch concentration, stirring or agitating the solution helps the individual starch chains hit and -briefly- stick to a high number of nearby chains, thus creating solid-looking blobs of starch. When the agitation stops, the chains go back to their original, "untangled" state, thus giving the solution its liquid-like look.

Corn-starch solutions are non-Newtonian fluids, which at certain starch concentrations behave as rheopectic (shear-thickening) ones. As you may suspect, depending on the corn starch solution and the agitation frequency, a number of cool effects can be seen. Check out the video below:

Beyond plain fun, fluids with such properties have a wide range of practical applications, from power transmission in mechanical systems to enhanced performance in bulletproof vests (traditionally employing polymer fibres).

I guess that the humble corn flour doesn't look that naive anymore, does it?