Curious Cook: Food, proteins and googly eyes on fish


  • Food News
  • Sunday, 23 Sep 2018

In South-East Asia, beef is often cooked with a lot of spices, as in this curry. Photo: The Star/Yap Chee Hong

My sister and her family recently came to stay in France, and one of their consistent comments was how good and “different” food tastes here – and were therefore curious about the “secret”.

Of course, there is no secret as such. For one, the food raised in France (and other parts of Europe) is different from food in Asia. By different, I mean the varieties of vegetables, fruits and animals here are distinct from other parts of the world. The preparation of the food is also often different, and I am also particularly fussy – for example, to get the right bangers for a barbecue, we made a return trip of around 100km to a butcher who sold sausages hand-crafted from pigs raised in the Cantal region.

There are, of course, several other items for which I would consider making such a long trip and top of the list would be good Malaysian durians – but sadly, there is no chance of that here as durians are still banned on flights.

This fussiness applies even to little things like salt. It is hard to believe but there are significant differences in the taste of salt. My personal preference is for Fleur De Sel De Guérande – if you are curious, try comparing a sample with ordinary salt side by side. The difference is usually due to the desiccants and/or flow-improvers in normal table salt.

French cheese Reblochon
French cheese Reblochon is made with raw, unpasteurised milk. Photo: The Star

France is largely agricultural and many regions are littered with remote farming communities where there is only one obscure road in and the same route out. Industrial farming is impossible and these communities mainly supply local markets with produce seldom contaminated by modern additives or processes used for mass production.

This is not always riskless – many fine French cheeses are made with “lait cru” or raw, unpasteurised milk and there was recently a recall of many tonnes of Reblochon de Savoie after some batches were found to be contaminated with E. coli. This outbreak had caused hemolytic-uremic syndrome in six out of seven affected children (though nobody died).

Statistically, this still makes eating Reblochon safer than crossing a road, so for that reason, such stories seldom bother me – though I would never offer young children cheese made with unpasteurised milk, just in case.

The right type of ingredients matter very significantly, especially in countries where there are few heavy spices to cover any deficiencies in food elements. For example, the closest to a French national dish might be boeuf bourguinon, a heady stew of beef, Provence herbs and red wine.

Boeuf bourguignon
Boeuf bourguignon is made with few ingredients, unlike a Malaysian beef curry (see main image, top), which is often heavily spiced. Photos: The Star

In theory, it should be very easy to make (as it is mostly boiling lumps of beef for hours in wine and herbs) but it took a year before getting it right. The main problems were the cuts of meat used and the wine selection, according to a professional cook. So changing the meat for a fresher tougher cut and using a lighter Cote du Rhone (and adjusting the balance of herbs) now results in a pretty good stew every time.

I would probably not bother to make boeuf bourguinon in tropical Asian countries. This is because most “beef” in many South-East Asian countries is actually water buffalo imported from India. The other issue may also be the freshness of meat in tropical climates. Meat decomposes and changes its flavour very quickly, especially at warm temperatures – this rapid decomposition is mainly due to aerobic bacteria breaking down meat proteins and spoiling the flavour.

Hence in the Far East, it would make much more sense to cook food with strong spices or flavours to counteract any possible issues with meat protein decomposition. And of course, this is what most people do.

fish
Check the eyes for freshness. Photo: The Star

Googly eyes

A funny story recently is the use of plastic googly eyes by a Kuwaiti fishmonger to cover the rotting eyes of old fish – a common way to test the freshness of fish is to check the decomposition of the eyes. The other is to check the redness underneath the gills. This indicates that consumers are acutely aware of the problems of protein decomposition.

Snack bars

This brings us round to the subject of proteins itself, especially in the modern diet. My daughter recently informed me that dietary protein is now such a fad that even confectionery manufacturers now offer protein-rich snack bars. This was a surprise to me, but a quick search proved she was right – you can get protein-rich Mars, Snickers and Bounty bars, for example. The Carnivore Diet is also an off-shoot of this protein fad. See “A modern food story – Part 1”.

Proteins

After ingestion, proteins are digested down into amino acids which are then released into the blood stream. Amino acids are extremely important as they are the building blocks of enzymes, antibodies, hormones, muscles and connective tissues such as collagen, without which the body simply cannot survive – and we cannot produce all the required amino acids so we require them in our diets. Humans need around 0.8g of protein per kilo of body weight.

One fact about proteins is they provide fewer digestible calories than carbohydrates and fat – as often stated before, not all calories from food are equal. This is because of the Thermic Effect of Food (TEF) which basically means that proteins take up five times more energy to digest compared to carbohydrates and fats. Hence, a piece of lean meat or soy protein delivers fewer calories than a fried doughnut of the same weight. This was reviewed in “The perils of dieting – Part 1”.

The TEF is also known as dietary-induced thermogenesis and appears to be the rationale behind many of the protein diet fads. Unlike dietary carbohydrates, which are chains of glucose molecules easily freed by enzymes (eg. amylase, galactose, sucrase, etc) into energy-giving glucose molecules, proteins are digested via a completely different pathway.

Proteins are more difficult to convert into energy for two reasons: (i) proteins contain nitrogen; and (ii) the digestive system needs to break down the peptide bonds holding together polypeptides. A string of amino acids is a polypeptide and proteins are either polypeptides or chains of polypeptides. Degradation of proteins is known as proteolysis and the first stage is denaturation of proteins in the extremely acidic environment of the stomach, plus the introduction of a stomach enzyme called pepsin. The deconstruction of proteins is further enhanced by the enzymes trypsin, chymotrypsin, carboxypeptidase A and B and elastase produced by the pancreas while passing into the intestines via the duodenum (where bicarbonate is introduced to raise pH to the level needed for the pancreatic enzymes to function efficiently).

After reducing proteins into amino acids, the amino acids are then passed into the intestinal cell walls and released into the bloodstream to be absorbed by other tissues.

Excess amino acids produced after digestion cannot be stored, and can then be converted into energy. These excess amino acids are subjected to processes called transamination and deamination, which remove the nitrogen molecules in amino acids, thereby reducing amino acids to carbon-based structures (such as pyruvate) which can be converted into glucose (energy) or stored as fat. The nitrogen is freed as ammonia, extracted from the bloodstream by the liver and passed for excretion by the kidneys as urea.

Due to the increase in urea production, anyone with chronic kidney diseases may be negatively affected by high protein diets. Healthy people generally have no issues with any amount of protein.

Although a high-protein diet may help weight loss due to the TEF of proteins, in many ways it is not significantly better than eating raw vegetables, which also have a high TEF. Also, a recent cohort study published in The Lancet (based on 432,179 participants) found that high-protein diets involving mainly animal proteins shortened lifespans (the reasons were not investigated). The study also suggested getting 50% to 55% of daily energy requirements from carbohydrates extended lifespans.

In summary, there is no compelling reason to pursue a high-protein diet but if you must do so, then consider a diet with a much higher proportion of non-animal proteins. There is even less sense in eating expensive sugary confections with added protein – if you investigate the protein content, much of it are by-products from other food processing. Examples are hydrolysed collagen, soy protein isolate, milk protein isolate, skimmed milk powder, whey protein, egg albumen, etc, all mixed with sugars and fats.


Curious Cook appears on the second and fourth Sunday of the month.


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