Food Product Design: Ingredient Insight - April 2005 - What’s Sauce for the Sushi

April 2005

What's Sauce for the Sushi

By Martin SchultzContributing Editor

The next time you immerse your sushi and sashimi in a bowl of soy sauce, you might want to consider what exactly you are dipping the fish into. Though used generically in a multitude of Asian dishes, soy sauce is in fact a highly complex ingredient produced in a wide range of textures and formulations. The sauce's consistency can range from very thin to very thick. From Thailand to Japan, soy sauce shows up in recipes calling for thick pastes, salty marinades and dark sauces, as well as in dips. In cooking, for example, it might heighten the meaty flavor in savory dishes while adding color and enhancing aroma. As a condiment, it unifies spice flavors in marinades and tempers the harshness of vinegar in salad dressings.

A legendary sauce Soy sauce has an ancient lineage, with the first reports of its use as a flavoring agent recorded as far back as 2,500 years ago. Soy sauce emerged in China, and its growth was enhanced when the country's Buddhist rulers decreed that vegetarianism would henceforth form the basis of its culinary culture. The requirement for a meatless seasoning prompted the evolution of a salty paste of fermented grains, including soybeans.

According to legend, a Zen priest brought the recipe to Japan, where the formulation underwent radical modification. Nevertheless, soy sauce did not start to taste like today's version until the 16th century. One of the improvements was adding wheat: It dramatically improved the taste, aroma and color.

Soy sauce is a salty brown liquid made from fermented soybeans typically mixed with another type of roasted grain (wheat, barley or rice are common), injected with a special mold, and flavored with salt.

Chinese soy sauces, which rely almost exclusively on a soybean base, come in two varieties: light, generally for cooking, and dark, for cooking and seasoning. The Japanese have five kinds of soy sauce: koikuchi (dark), usuikuchi (light), tamari (very dark), shiro (white) and saishikomi (twice-fermented, thick and dark), differentiated by region, production process and ingredients.

U.S. tamari distribution has increased recently. "Tamari has a higher degree of protein achieved from higher amounts of soybean," says Herb Bench, general manager of Nikken Foods, St. Louis. "Because of the added protein, tamari provides a higher degree of flavor enhancement for meat applications."

Soy sauce is produced either by "natural" brewing or a chemical process. Natural brewing or fermenting has been the favored traditional approach and has some of the production attributes used in wine and beer making. "Soy sauce contains amino-acid profiles with generally higher amounts of glutamic acid that contribute to its flavor- enhancing characteristics," says Bench. "Naturally fermented soy sauce has a flavor that is complementary to many savory food systems."

Zen art of brewing The natural brewing of soy sauce relies on a three-stage process over a period of several months. Traditional Japanese brewing begins by combining soybeans and wheat under controlled temperature and humidity. Processors introduce a seed mold, typically Aspergillus oryzae, and the mixture allowed to mature for 72 hours to produce koji. The koji is then transferred to fermentation tanks and mixed with saltwater. This creates a mash the Japanese term moromi. What happens next is perhaps the most critical step in the whole process. Using a variety of lactic-acid bacteria and yeasts, the moromi is allowed to ferment over a period of several months. The culture takes on a semi-liquid characteristic. During   aging, the sauce acquires distinct flavor and fragrance components.

The final step is refining, in which the raw soy sauce is filtered out. The resultant liquid is refined, pasteurized and packaged.

With the nonbrewed process, soybeans are boiled with hydrochloric acid for between 15 and 20 hours. Once the soybeans have yielded their maximum output of amino acids, the mixture is cooled to prevent further hydrolytic reaction. At this point, the amino-acid liquid is neutralized, mixed with active carbon and purified through a filtration process. Processors that use this technique add various ingredients, such as caramel color, corn syrup and salt, to this hydrolyzed vegetable protein mixture to provide its characteristic appearance and mouthfeel. The mixture is then refined and packaged.

Disparate descedants The two methods of production yield very different products. Perhaps the most-important difference is the complexity of flavor. Brewed soy sauce contains almost 300 identifiable constituents.

"During the fermentation process in naturally brewed soy sauce, many flavors are generated," says Yukio Mogi, marketing manager, retail and industrial, Kikkoman International, San Francisco. "It is just like the fermentation of wine. Because chemically made soy sauce has only a short period of this process done by biochemical reaction, it cannot gain the same flavor components that are developed during the natural-brewing process."

Much of the flavor of soy sauce comes from the amino acids resulting from the breakdown of soybean proteins by the fungi in the koji. Other factors include the type and presence of such components as sugar and color, in addition to aromatic esters, post-fermentation development and salt.

Salt illustrates the critical synergy among soy sauce's many constituent parts. With the natural-brewed version, all the constituent parts form a smooth flavor. Nonbrewed sauce tends to have a harsher salinity in its taste, perhaps from chemically blending the ingredients instead of allowing them to fuse over time.

Enhancing the category One of the biggest challenges to greater U.S. usage of soy sauce is precisely because of the extra high levels of sodium. Yet salt is such an integral ingredient of the taste that consumers can notice its reduction or absence.

The sodium chloride content of our regular soy sauce is about 13.7%, while that of reduced-sodium types are about 8.4%, according to Mogi. "Many people tend to think that Less Sodium Soy Sauce is made with less sodium during its fermentation process, but it's not true," he explains. "Our Less Sodium Soy Sauce is made from regular soy sauce and then removing the sodium ion by a special filter. Thus, most flavor components still remain in the product, and you will still enjoy the same depth of flavor that we have in regular soy sauce."

Another flavor solution is a natural blend of fermented soy sauce and yeast extract that functions as a potent replacer for other flavor enhancers. Bench notes that a synergy between the soy sauce and the yeast extract appears to exist. Not only does this ingredient function as a sodium-reducing element, but it is also kosher certified and has applications in meat products, soups, gravies, rubs and spice mixes.

Beyond the sushi bowl Manufacturers supply soy sauces in a variety of formats, including liquid, powder, reduced-sodium, preservative-free and clear types. The right ingredient depends on the   product formulation.

For example, according to Mogi, powder is desirable in dry applications, such as snacks and seasoning mixes. "It tends to absorb moisture, so we recommend granulated soy to those manufacturers who care about moisture levels during their production process," he notes. "The recommended reconstitution is 1 part powder soy to 11/3 water."

Widely perceived as a savory flavor enhancer for Asian foods, manufacturers have discovered that soy sauce's many nuances allow use across a range of ethnic cuisines. For example, many people have been pleasantly suprised to see soy sauce in a Mexican beef fajita sauce. "Soy sauce enhances meaty flavors found in meatless foods like veggie burgers," says Bench. However, "it is also used in Mexican fajita mixes and barbecue sauces."

Soy sauce has also migrated into Caribbean food as a component of Jamaican-jerk sauce and spicy marinades. It has found its way into English sauces, such as Worcestershire and steak sauce. Also, soy sauce has become a staple in the homes of many American consumers, serving to add a bit of flavor to such foods as meatloaf, snacks and specialty cheese.

Martin Schultz is an experienced consumer and trade magazine writer with a special interest in food and food-technology topics. He can be contacted at [email protected] .

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