Trends for Yeast Extracts in its Use as a Seasoning and Flavoring in the US and European Markets.
Tilak Nagodawithana PhD Esteekay Associates Inc. Milwaukee, WI 53217 USA
Tilak Nagodawithana PhD Esteekay Associates Inc. Milwaukee, WI 53217 USA
Flavor is one of the most important attributes governing the selection of foods we eat. Early civilizations have relied upon their good sense and experience to develop and improve their food quality, which in the process, probably led to the development of their traditional foods. The empirical knowledge they acquired was subsequently transmitted throughout the ages to succeeding civilizations. Today, with this know-how, combined with new technology on the skillful use of ingredients in the art of cooking, fascination with food has become a basic human experience to many.
In most cases, foods require additional flavorings during or after processing to make them more palatable. The significance of a very familiar taste like that of common salt is well known to both food processors as well as to the consumer. Many other flavorings are now being marketed to improve the flavor characteristics, particularly of convenience foods.
Among the earliest savory foods, the best known fermented savory flavoring or seasoning that has a long history in the Orient is soy sauce. Although the information relating to this product is fragmentary, the authentic records of the Chinese using soy sauce as a flavoring agent may date back approximately 3,000 years (Prinsen-Geerligs, 1896). Today, without doubt, the discovery of soy sauce is rated one of the outstanding achievements made by man in the area of food science. The popularity of soy sauce as a savory flavoring has clearly soared in the Western world during the last few decades.
In 1886, Julius Maggi, (Heer, 1991) a pioneer in the food industry broke new ground by developing rapid-cooking dehydrated soups. One of the key ingredients he utilized in his formulation was hydrolyzed plant protein. These hydrolysates yielded the meaty flavoring necessary to make these rapid-cooking soups, meaty and so enticing. This eventually evolved into an important business segment in many parts of the world.
During the last few decades, yeast extracts have become popular in part due to their usefulness as a natural flavoring agent and a flavor enhancer as well as for its cost effectiveness compared to other flavoring agents on the basis of equivalent flavor intensity.
2、Characteristics of Yeast Extracts:
Yeast extracts are a perfectly natural source for savory flavor and a seasoning for use in a wide variety of food formulations. Yeast extracts are produced by a process called autolysis, which is essentially a self-digestion of the yeast, which requires the mediation of several endogenous hydrolytic enzymes. The process is generally initiated by the application of carefully controlled conditions such as temperature and pH, so as to achieve cell death with out inactivating the natural hydrolytic enzyme. At the end of the autolysis or self digestion, the entire material is centrifuged to separate the cell wall fraction from the clear supernatant extract. The later fraction which we refer to as yeast extract is concentrated to a paste or concentrated and spray dried before packaging to ensure its stability of the product. Some times, the entire digested yeast with the cell wall fraction is dried without separation and the product is termed an autolysate which food processors find use in certain specific applications.
The best-known extracts are derived from specially selected strains of primary grown baker’s yeast. However, similar yeast extracts can also be made from other species of yeast such as torula yeast (Candida utilis) grown on ethanol, Kluyveromyces marxianus grown on whey or from spent brewer’s yeast.
The key factors in choosing the starting yeast for processing are the price, availability of the yeast itself, and the properties desired in the final product. Baker’s, brewer’s, and Torula yeast strains serve as common substrates but in general, brewer’s yeast require a pretreatment prior to use. Yeast extracts have become popular during the last few decades in part due to their usefulness as a natural flavoring agent The amino acids have been of primary importance because of the characteristic taste profile they collectively impart, and most importantly, for their ability to serve as precursors for flavor development through Maillard reaction.
Heat treatment plays a very important role in the production of flavor compounds in yeast extracts. These heat-induced changes in an aqueous phase are caused by complex thermal reactions between proteins, amino acids, carbohydrates, fats, organic acids, vitamins, etc. The process is referred to as non-enzymatic browning or Maillard reaction, named after the discoverer. This reaction which in reality is a complex system of reaction pathways, is important in developing the desirable aroma and non-volatile savory taste chemicals of cooked, roasted, fried or baked foods. Browning and aroma formation accompanying such heat processing are essentially caused primarily from the reaction of carbonyl groups of reducing sugar or related carbonyl compounds with free amino groups of amino acids or peptides. These are precursors generally present in yeast extracts and almost all savory food systems prior to heat processing. The variety of aroma compounds, which can arise from the Maillard reaction generally, varies both in number and complexity based on the reaction conditions.
It is the taste that is the most influential in determining how delicious a food is. Conventionally, it has been thought that our sense of taste is comprised of four basic, or ‘primary’, tastes, which cannot be replicated by mixing together any of the other primaries: sweet, sour, salt and bitter. However, it is now accepted that umami is actually the fifth primary taste and the word of umami is now used internationally to describe the taste elicited by glutamate, 5’- GMP and 5’-IMP. The presence of glutamic acid and its flavor enhancing sodium salts thus serve an added advantage to those who use yeast extracts in product formulations. Certain peptides are also known to provide brothy character in soups and gravies and enhance certain targeted flavors.
It was K. Ikeda who first coined the word umami in 1908 to identify the distinctive taste of glutamate isolated from gluten. There is no English word synonymous with umami. However, the closest related terms are savory, meaty and broth-like. Because umami was originally a Japanese term, it is often thought to describe a unique, oriental taste familiar only to the Japanese and other Asians. It was not until 1913, when Ikeda’s protégé Dhintaro Kodama completed his studies on bonito flakes that the role of inosinate in umami was clarified. The identification of the third element in umami which was 5’-guanylate had to wait until Akira Kuninaka’s studies in 1960. The same year saw it extracted from the broth of mushroom, shitake.
The yeast extracts described earlier are generally considered more as flavoring agents rather than enhancers because its – nucleotides. In a typical autolysis¢final extracts lack the flavor enhancing 5 -nucleotides because yeast does not¢process, nucleic acids are converted to 3 -nucleotides.¢have the necessary enzymes to convert RNA to flavor enhancing 5
The type of flavor enhancing yeast extracts that are currently marketed have the -IMP and the¢-GMP and 5¢-nucleotides, 5¢flavor enhancing properties of the two 5 glutamate formed by the hydrolysis of proteins in the yeast. These yeast-based flavor enhancers are known to give an additional boost to the overall flavor of a food system including salt perception, green herb and brown spike notes and spice heat. Most of all, flavor enhancers in yeast extracts contribute to the ‘umami,’ the 5th basic taste that is often described as savory or brothy.
The flavor enhancing effect of umami substances on the palatability of different types of foods has been extensively investigated. The most important phenomenon exhibited by such flavor enhancing compounds is their ability to show synergy -IMP and glutamate. This type of synergy, not common to other¢-GMP, 5¢between 5 taste attributes, is one of the most remarkable properties, common to these flavor potentiators.
-I+G flavor-enhancing nucleotides have the ability¢Yeast extracts containing 5 to not only provide the enhancement of the savory flavor system but also to contribute the basic flavor building blocks that can mimic the nondescript savory background taste profile, traditional to homemade foods. Product designers often add yeast extracts, perhaps with HVP to vegetarian products such as soy-based burger patties or chicken substitute nuggets and fingers to mimic the savory flavor profile of their meat counterparts. (Fig 15) These yeast-based ingredients contributing naturally occurring glutamic acid and flavor enhancing -nucleotides do not require additional labeling. These yeast extracts may¢5 simply be labeled as ‘Autolyzed Yeast Extracts’ (USDA) or as ‘Yeast Extracts’ (FDA).
Modern food processors utilize these flavorings and all the technical resources available at their disposal to skillfully generate the proper balance in the final savory character of their culinary creations.
3、Advantages in the use of yeast extracts:
In recent years there has been some decline in the HVP usage due to reports that it is carcinogenic. This has been due to the detection of certain chemicals called 3-MCPD (3-monochloropropane-1,2-diol) and 1,3-DCP (1,3-dichloro-2 propanol), which may be formed by the reaction of chlorides with lipids during cooking.
. Admittedly, some of the trace chemical compounds found previously in HVPs have shown mutagenic properties As a result of this development, the market for yeast extract based flavour enhancers has improved markedly. New technologies developed lately have been able to bring the levels of these compounds below 5 ppb in the HVPs. Nevertheless, rumors and stories persist for long periods and many product designers seek to avoid or drastically reduce the level of HVP usage in product formulations. As compared to HVP, yeast extracts have not entered into any major controversy and is currently preferred over the former by the leading users of savory flavors worldwide, particularly in the soup/sauces sector.
Additionally, in the US and Europe, the use of chemical MSG has fallen to disfavor among many consumers. According to a FDA’s report, MSG symptom Complex or MSG side effects can result in numbness, burning sensation, tingling, difficulty of breathing for asthmatics, etc, among those who appear to have affected by this chemical. Because of this, most multinational food companies with huge investments in brand values have chosen not to risk possible damaging publicity by reformulating their relevant savory products with appropriately chosen yeast extracts. Such extracts are known to work synergistically with the flavor components of the base food and even smooth out any harsh flavor notes which may seem objectionable to a taster further rounding off and balancing the overall savory character in foods. They contain strong flavor intensities offering low usage levels and thus relatively lower costs in formulating a wide variety of food products.
This glutamate is a vital neurotransmitter – a chemical which allows communication between neurons – cells in the brain. There are in fact glutamate receptors in every major human organ. Natural glutamate consists of two amino acids – glutamic acid and glutamine, which are partially bound up in the protein molecules of yeast, yeast extracts and other natural foods. In the body, these proteins are slowly broken down which means the glutamate is released gradually and can be absorbed naturally at a manageable pace. The free glutamic acid in yeast extracts are relatively low and of the concentration that will not produce a harmful spike in the body when consumed.
On the other hand, pure MSG contains much higher levels of glutamate than occurs naturally in extracts or other natural foods. MSG is not bound in a protein molecule – it is free and is therefore absorbed by the body at a faster level than natural glutamate. If too much glutamate is consumed, the body normally pumps the excess glutamate out of the neurons and into the surrounding helper cells – astrocytes. However, if the levels of glutamate are too high, as occurs when the body ingests MSG, the body cannot pump out the excess and the neurons become over-stimulated and disoriented. An MSG sensitive person in that case experiences such discomfort when MSG is consumed with the food.
Yeast extracts made from baker’s, brewer’s or torula yeast have now become key elements in the development of most savory flavor systems. The major contributors from such yeast extracts are derived from the hydrolysis of macromolecules present in the yeast cell and their reaction products formed by their mutual chemical interactions, primarily during concentration, pasteurization and drying.
Yeast extracts serve as a good source of flavors as well as flavor precursor compounds that include amino acids, sugars, peptides, nucleotides and B-vitamins that are useful in the development of meaty, savory flavor. For this reason, yeast extracts are a key component that allows flavor houses to create savory flavors and top notes for a variety of savory foods through reaction or processed flavor technology.
3、Introduction of Yeast Extracts in Foods and Seasonings:
With the greater emphasis on natural flavors in foods, there has been a revival of interest in yeast extracts. If product designers find certain savory nuances missing in finished products or they just want to boost up a weak flavor, or to introduce new flavor variations, they can now find yeast extracts to which is a natural food ingredient to fill this gap. Yeast extracts are generally used at 0.1 to 0.25% on a finished product basis. Yeast extracts typically intensify and round out flavors and provide intense meaty notes in appropriate applications. They are often applied in food systems, as they are capable of providing the missing links to look like homemade foods. Yeast autolysates which have less intense flavors due to dilution effect by the presence of cell walls, are also typically used at 0.5 – 1.0% in food formulations.
Within the food industry, the key sectors to account for its high demand for yeast extracts are soups, bouillion, sauces, gravy, ready-to-eat meals, seasonings and savory snacks. Apart from these direct purchasers of yeast extracts and enhancers, flavor houses and seasoning houses can also be considered as demand sectors since they often add value to these products and market the resulting seasonings to the food producers. Yeast extracts are extensively used in improving the flavor characteristics of soy sauce by rounding of its flavor profile, reducing Na content and by masking any unpleasant notes. In addition, an impressive growing demand of the boullion sector is being explained by the presence of Wűrze and Marmite, two of the largest user-segments of savory flavors enhancers in Asia, Australia and Europe.
All yeast extracts contain certain peptides and amino acids and some contain flavor enhancing 5’-nucleotides which are known to provide the brothy character to the aforementioned savory food categories. Additionally, desirable flavors can also be supplied by reaction flavor compounds that develop at high temperature processing. Yeast extracts also contain natural glutamate and certain other grades contain higher levels of flavor enhancing 5’-I+G.
4、Evolution of Yeast Extracts in the US and Europe:
The start of yeast extract production dates back to early 20th century. It was in 1902 that the Marmite Food Company (later Marmite Ltd) was set up in the United Kingdom. Their mission, then as now, was to produce yeast based nutritionally-rich product called Marmite with excellent taste. The basic production method has changed little since Marmite was first invented. Basically, the used brewer’s yeast is broken down to release soluble amino acids and proteins. This soluble material is then concentrated and filtered a few times before going through a unique proprietary process for flavor development. Finally, what ends up with is a yeast extract paste. The product is then blended with vitamins, vegetable and spice extracts to create the taste the world now knows as Marmite. By the time of the First World War it was included in soldiers ration packs. It also became a staple food in hospitals and schools. During World War II, Marmite became a dietary supplement in prisoner-of-war camps.
With these humble beginnings, yeast extract business today has blossomed into a very lucrative industry providing a spectrum of savory flavors and seasonings primarily to the food industry. Although the early innovation in yeast extract production from brewer’s yeast started in the early 1930’s, the products were not well received in food formulation due to its inherent bitter taste. This was soon overcome by the use of baker’s yeast which is a primary grown yeast which is a much cleaner yeast than the brewers yeast that have the residual effect of hops.
In the mid 1930’s Götz Ohly was the first to develop yeast extracts from primary grown yeast and he still lends his name to the company and the branded range of bakers yeast derived products. In 1961 the company was converted to Deutsche Hefewerke GmbH (DHW). Today, yeast extracts are made very extensively in Europe with production to a lesser degree in the US & Canada, China, South America and Australia.
Up till the 1960’s, the markets dominated with brewers and bakers yeast extracts in the form of paste and a lesser amount in the form of powder. With the advent of efficient dryers and improvements in the techniques of drying, more and more users of yeast extracts have preferred the powder over paste and today, yeast extract are predominantly available as fine powders or agglomerated or oil treated powders for convenience. These extracts were basically produced from bakers or brewers yeast using a simple autolysis procedure. The critical flavors were derived from the breakdown products of proteins and the reaction flavors generated during downstream processing.
By mid 1970’s, the use of enzymes to enhance the autolysis process was first started in order to improve extract yield and flavor properties of the yeast extracts and to bring down the cost of production. This improved the free glutamic acid levels of the extracts thus making the products more acceptable in the application of foods and seasonings. An important development during this era was the use of special enzymes for the production of flavor enhancers such as 5’-IMP and 5’-GMP from yeast. This breakthrough made a significant impact, even though slow at the beginning, in providing a replacement for MSG which the consumer was beginning to monitor in the prepared foods they consumed.
5、Production and Producers of Yeast Extracts Worldwide, 2008.
In this section, I wish to now review the list of major producers by regions with details on their output of yeast extracts for the year 2008 and the forecast for the year 2009. This information is summarized in Slide 14 which indicates that the worldwide output amounts to approximately 124,000 tons for the year 2008 for the free market. In addition, 12,000 tons yeast extracts are produced primarily from brewer’s yeast for captive use.
Based on the estimated worldwide output of 124,000 tons of yeast extract for 2008, Table 6 presents the projected output for the coming year 2009, assuming a 3% or 5% increases in demand for the food industry. This would amount to a total increased need of 7,300 ton extract for an increase of 3% or 10,400 tons requirement in case of a 5% increased demand in which case the total forecast for the year 2009 would amount to an output in the 131,300 and 134,400 tons range.
6、Trends for the Future
Today, the food industry is demanding much more innovations on the part of the ingredient suppliers as a direct response to more recent challenges placed by the health-conscious consumer. These include: (1) no chemical MSG (2) no HVP (3) gluten-free (4) no trans fat (5) low Na, etc. Consequently, there is a great deal of research activity taking place with in the extract manufacturing community in response to these demands.
The Western World, which now produces and consumes vast quantities of animal meat may, in the future experience shortages that could result in dramatic changes in food habits. Additionally, consumers have now become exceedingly conscious of their health and this too has caused a dramatic reduction in the inclusion of meat in their diets. In response to these pressures and consumer demands, meat analogs are becoming increasingly popular, and as this occurs, production of meat-like savory flavors or process flavors will be of ever increasing importance throughout the world.
The general trend for future is to produce yeast extracts that contain:
(a)Very high 5’-I+G (perhaps in the range of 15-20%) (b) Reaction flavors to mimic savory meatiness of chicken, beef, pork, turkey, etc. specially for formulating foods for vegans and vegetarians (c) Low sodium extracts for health conscious consumer (d) Extracts to imparts freshness to formulated foods (e) High natural glutamic acid in extracts for flavor enhancement (f) Cleaner products with less color (g) Product with minimal or no odor
It is the responsibility of the food scientists, flavorists and product designers to develop savory richness in diets low in meat or low in salt in those diets that are rich in vegetable proteins. Currently, there is considerable interest to produce very high 5-nucleotide-rich yeast extracts for use in flavor enhancement.
Current research is devoted more to the identification of character impact compound to savory flavor and to maximize the production of these flavor chemicals through reaction flavor technology. Understanding the kinetics of these reactions would be helpful to activate only the relevant pathways that would generate the desired flavors with out the release of undesirable flavors. In the future, we can expect to see further interest in model systems for both knowledge building as well as for practical use.
The affects of “low sodium awareness” are also being seen in food service, particularly in the developed world. Accordingly, the food processors are under pressure to reformulate products and re-label packages to help consumers understand what they are eating. In response to these changes, yeast extract manufacturers are compelled to produce and market products low in sodium to stay in business.
The quest for controlled flavor release will continue to remain a high priority to those who are in the business of formulating prepared foods. The basic intention is to provide the fresh flavor notes that are reminiscent of fresh homemade foods. One approach that has not yet reached perfection is to add flavor precursors, which may include specially designed yeast extracts and protein hydrolysates, additional to flavorings. The product designers are aggressively making headway to take the best advantage of this approach. The hope is that such well-defined flavor precursors introduced into the formulation would generate the characteristic taste and aroma during the final heat treatment just prior to consumption to make the food resemble more close to freshly prepared foods.
A few well-known food research laboratories have come closer than ever before in acquiring control over the process to achieve flavor development through the application of model systems. These developments have set the stage for flavor chemists to utilize the power of computers to assist in steering reactions to generate definite flavors, important for new product development. This will allow the food research to gradually move away from “hit-and-miss” type approach to a more defined and predictable flavor design and flavor engineering approach in the future.