Mayonnaise,Tempura and sake4th Installment

Mayonnaise,Tempura and sake4th Installment

A Matter of Taste (from the perspective of viscosity)

We would like to end our 3-part series on 'viscosity in our daily lives' on a somewhat lighter note with this extra column.

What is mayonnaise?

In the first installment, we explored the components of chemical taste and physical taste. Texture is the main component of physical taste. How taste can be brought out through texture is an extremely important aspect in processed foods. In addition, even with a change in ingredients, it may be possible to create a facsimile of the real thing through skillful manipulation of texture. For example, it is possible to reduce calories in a food while still maintaining its taste and texture.
Let us look at mayonnaise as an example of this. There are many lovers of this condiment. A downside of mayonnaise though (for those who care), is its high caloric content. This drawback has spurred the creation of low calorie versions which boast reductions in calories of as much as 50 to 70%. Calories in mayonnaise can be reduced by cutting back on the amount of vegetable oil and other ingredients used. Such products offer the best of both worlds with greatly reduced calories but with the same good taste. But is this mayonnaise? If you look at the food label of such a low calorie products, it is apt to be described as a “creamy-type dressing” or something similar. In Japan, “real” mayonnaise and low calorie substitutes are considered separate categories of product. JAS (Japan Agricultural Standards) strictly defines the composition of products that may be labeled “mayonnaise”. Such products must have an oil content exceeding 65%. Thus a 50% oil-reduced product cannot be called “mayonnaise”.
This fact notwithstanding, the general consensus would likely be that - from the standpoint of chemical taste and texture - such products taste like real mayonnaise and the majority of people would not be able to distinguish between the two. To them mayonnaise is mayonnaise, whether it is called something else and has a caloric content half or 70% less than the real thing.
Considering this aspect further however, one may think it somewhat strange that the texture of a food remains the same even when the amount of oil is greatly reduced. The answer lies with thickeners and the subtle manipulation of textures. Take, for example two people who look identical but are not siblings. This may lead to problems in real life which may necessitate DNA testing in the extreme case that it becomes necessary to distinguish between the two.
In the world of food products, viscosity measurement provides a means of revealing differences without resorting to such measures. If ingredients in a food differ, viscosity characteristics would obviously not be the same. No matter how similar they may seem, the differences in identity soon becomes apparent.

Tempura - a scientific view

Let us look at cooking and viscosity.
Tempura is one of the dishes which demonstrates a cook’s skill. The ingredients used in tempura include the raw materials such as fish, shrimp, and vegetables as well as flour (and water) and oil. The raw materials are coated with flour and deep fried which is a rather simple process. The artistry of the professional chef comes to fore in his efforts to retain, as much as possible, the original flavor of the raw materials during preparation of this dish. In home cooking however, results are likely to be less-than-ideal with the tendency for the tempura to come out greasy. But while it may be a challenge to attain the same standards of specialty restaurants, it should still be possible when preparing tempura at home to achieve almost-as-good, light and crisp results by paying attention to the flour and oil used
One tip is to use flour made for tempura cooking rather than regular soft flour.
A second tip is to use oil that is as fresh as possible with good drying characteristics.
Tempura, to begin with, is a dish where moisture in the batter is replaced by the oil during the cooking process for a crisp outside which locks in the flavor of the baked ingredients. Batter not prepared well (such as “drippy batter”) may hinder this smooth exchange of moisture and oil. If the temperature of the water used to mix the flour is high or if the batter is mixed too thoroughly or vigorously, the result will be gluten. Gluten obstructs the replacement of moisture with oil. Techniques employed to suppress the formation of gluten include adding cold water little by little into the mix, adding baking powder, and using specially formulated tempura flour with a low protein ratio.
One flour manufacturer boasts that their tempura flour contains, in addition to wheat flour, “. . . pumpkin powder (patented), egg powder, baking powder, emulsifiers, and other ingredients” and there is keen technical competition among such producers to market introduce flour which enables anyone to create perfectly crisp tempura.
Still, all efforts to achieve crispy results may come to naught if excess oil is not shed properly. The key here is to use new and fresh oil instead of “tired” recycled oil. The correct frying temperature is also important. It is said that the key to deep frying tempura rests, firstly and secondly, with maintaining the proper oil temperature. Ideally, tempura should be deep fried at a high oil temperature of about 180°C (within an upper and lower band of 10°C depending on the type of raw material used). If oil temperature is low, viscosity will be high and the result will be tempura which is sticky and soggy. Given this fact, you may think that a quick dip fry in oil which is at high temperature would produce good results. Not so. Oil at high temperature means lowered viscosity, but unless the cook is proficient, the result may be an inedible concoction that is scorched on the outside but raw on the inside. In addition there is the problem of oil oxidation. Cooking oil used repeatedly will oxidize and deteriorate and the viscosity of such oil will rise. Tempura prepared with this kind of oil will be greasy and is liable to give you heartburn.
You may thus appreciate how - through technology - control of viscosity has now become an important factor even in the preparation of traditional Japanese dishes like tempura.

The perplexing "smooth & refreshing" but with "body" dilemma

Bliss for many Japanese is enjoying tempura with a good drink accompaniment. Traditional Japanese sake is fine but it is hard to beat the clean flavor and refreshing aftertaste of a good beer with this dish.
Let us take a brief look at alcohol and viscosity. Liquor has texture due to its content of alcohol and extracts. This fact makes it possible to represent qualities of smoothness and other attributes in terms of viscosity. If we take viscosity samples of various types of liquors (20ÅãC circulating bath temperature) we obtain values such as 3mPaÅEs for whiskey (alcohol content: 43), 2.52 mPas for Japanese sake (alcohol content: above 19, below 20), 1.84 mPas for wine (alcohol content: 11), and 1.67 mPas for beer (alcohol content: 4.5) and we can see that the higher the alcohol content, the higher the viscosity.
From this, you may also expect that viscosities would rise in proportion to the increase in alcohol content. Interestingly, this is not the case. When we measure an ethyl alcohol aqueous solution, we find that with an alcohol content in the 45% range, viscosity will peak at 2.9 mPas and then begin to fall as alcohol content increases beyond this point. Viscosity of an alcohol aqueous solution increases as the result of hydrogen bonding and gathering of alcohol and water molecules. However as the concentration of alcohol reaches the saturation point, the gathering of molecules ceases and viscosity starts to decrease as the number of pure alcohol molecules increases. Thus the texture of a liquor with a high level of alcohol may not necessarily be thick.
With regard to the smooth & refreshing but with body problem, let us examine two aspects of a well-known beer - Super-Dry - that was responsible for the dry beer boom in Japan. One aspect of this beer is its higher alcohol content compared to other regular commercial beers. Until the introduction of Super-Dry, the alcoholic content of most beers was in the 4.5% range. Super-Dry offered an increased alcohol content of 5%. (Perhaps as the result of this, most regular beers now sport a 5% or higher alcohol content.)
The second aspect is that Super-Dry managed to achieve both body as well as a smooth & refreshing taste. As mentioned, when alcoholic content rises, so does viscosity. Higher viscosity results in more body (although this cannot be said of low malt beers) but this normally also results in diminishing the sensation of smoothness as it goes down - a problem if you are striving to attain both of these attributes in the same product. How Super-Dry managed to accomplish this is a company secret. Some speculate that this was due to the beers higher carbonation or other reasons. But the fact remains that Super-Dry is now the number 1 selling beer in Japan because of its success in solving this dilemma.
Again, an important point is that viscosity changes with temperature. As temperature increases, viscosity decreases and vice versa. Thus it may be appropriate to offer a word of advice and caution if you are contemplating imbibing your favorite Japanese sake (or hot toddy?). Beware of the attendant results as sake drunk hot flows easier than sake drunk cold!
Our next series of installments will deal with the theme of adhesives and viscosity.

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