Gastronomic engineering (GE) is “… applying concepts of food materials science as well as methods and tools of food engineering to guide the physical and chemical transformations of culinary practice and design novel structures that, according to chefs, are uniquely tasty and palatable” (Aguilera and Lillford, 2008).FACTS ABOUT THE RESTAURANT INDUSTRY
Higher incomes, increased urbanization, and less time for food preparation cause consumers who live in modern societies to spend an increasing percentage of their food expenditures eating away from home. This number is reaching almost 30% in the United Kingdom, and 42% in the United States. According to Forbes magazine, worldwide annual sales of the restaurant industry are estimated to be around $1.5 to $2 trillion. In the United States alone, the restaurant industry sales were estimated to have reached $537 billion by 2007. In the period 2000–2020, per capita expenditures in restaurants are expected to grow by 18%, while those in fast-food outlets only by 6%.
Furthermore, there is an emotional component to this growth. A sizable proportion of consumers—almost 40% in the United States—prefer restaurants for an enjoyable dining experience (Stewart et al., 2006).
Gastronomy and the industry of fine dining are becoming major drivers for food innovation. Top chefs, often the owners of high-quality restaurants, are evolving into major protagonists of a paradigm shift in modern cuisine characterized by the increased use of scientific knowledge for the development of new dishes (Vega and Ubbink, 2008). Several of these high-ranked chefs are celebrities as well as multimillionaires, their empires are based on the restaurants, cookbook sales, endorsement of product lines, and TV performances.
According to a salary survey done in 2005 15% of executive chefs in fine dining establishments in America earned annually over $100,000. Enthusiasm for fine dining does not stop with celebrities. According to Cowen (2006), expenditures in the highest-quality restaurants in Paris (i.e., Michelin dining guide categories from “very comfortable” to “luxury”) tripled between 1950 and 2005, adjusted for inflation. Today, a meal in a Michelin three-star restaurant in Paris can cost $300 or $400 a person, not including wine. By contrast, the cost of eating in non-luxury restaurants became cheaper in period. The economic consequences of this trend has led to the formation of "The Society of Quantitative Gastronomy" described as “a scientific organization where mainly economists, econometricians, and managers bring their professional know-how and knowledge to gastronomy.”
GASTRONOMY: ART OF COOKING AND PLEASURE OF EATING
"La cuisine est le plus ancien des arts"(Antoine Brillat Savarin, 1840).
The Larousse Gastronomique defines gastronomy as “… the art of good eating.” In France, the word gastronomy came in general use around 1800 and was accepted by the Academie Francaise only in 1835 (Montagne, 2003). Another definition of gastronomy is “… the art or science of good eating” (Gillespie, 2001). While gastronomers are referees of taste and define what may be considered gastronomic, a gourmet is someone interested in and has learned the connoisseur of table delicacies (Gillespie, 2001).
Traditional gastronomy is based on recipes passed from one generation to the next. These recipes embody all the information needed to construct gastronomic dishes, albeit in an imprecise way. According to This (2005), recipes comprise two parts, the first having to do with the ingredients and the second with the succession of processes and devices necessary to achieve the expected results. While ingredients are more or less well defined (but now in constant evolution), it is the process that needs “precision.” Recipe nomenclature such as “stir slowly,” “bake with oven door open,” “add drop by drop,” and so forth often represent 80% of the text. The steps in preparation are crucial to the success or failure of the preparation. In a positive way, this vagueness permits experimentation by cooks and is a source of variability, creativity, and differentiation.
The pleasure of eating is largely a perception of breakdown of food structures in the mouth. Enjoyment of a meal would not be the same if its contents were reduced to purees, even though all chemical components would be the same. Indeed, some foods such as meat, corn flakes, and cucumber are actually not recognized by most consumers when their structure is obliterated into purees, with flavor becoming the only attribute for identification (Bourne, 2002). Although it is proverbial that “food enters by the eyes,” most desirable structural attributes of foods are at a level beyond the resolution of our vision (approximately 100 mm). Texture perception and flavor release, among other properties, depend on food microstructures formed by nature or created during processing and cooking (Aguilera, 2005).
ORIGINS OF SCIENTIFIC CUISINE
When it comes to the art of cooking, great chefs in the late 1980s must have felt like painters at the end of the nineteenth century. These artists realized that reproductions of the common life by the masters of the Renaissance could not be surpassed, perhaps only imitated or duplicated. Precise imaging of the visual world, the new technology eventually to be called photography, was becoming popular. Painters at that time turned to explorations with colors, shapes, and subjects adopting new materials and techniques. Almost in the same period, architects discovered that their trade and engineering need not remain estranged from each other but on the contrary, both could benefit by using new materials and techniques to built astounding structures, for example, skyscrapers (Gombrich, 1995).
A similar evolution occurred in the 1980s in the field of haute cuisine. Local ingredients and traditional cooking had been exploited to their full extent for a couple of centuries since the restaurant became established in Paris around 1765. The ambiguity of most recipes alluded before provided the opportunity for experimentation and change. Some of the prefixes ascribed to this modern type of cuisine are fusion, nouvelle, and author’s, hyper, experimental, and techno-emotional.
All these terms attempt to capture the efforts by modern chefs to break up with the rigidity imposed by traditional ingredients, cooking methods, and tastes of classical gastronomy. Like architects and engineers in the past, chefs and scientists have realized the enormous potential of combining creativity and scientific knowledge to develop new foods and new sensations. In this context, the book of McGee (1984) became a classic in describing the scientific understanding of science-based cooking.
The term “molecular gastronomy” was coined by Herve This and the physicist Nicolas Kurti in 1988 to refer to the “scientific” aspects of culinary transformations and the sensory phenomena associated with eating (This, 2006). According to them, molecular gastronomy is not molecular cooking, because cooking is a craft or an art, and not a science. They argued that scientific knowledge was needed to explain why some recipes work and some did not, to give chefs and cooks (including amateurs cooks) a basis for innovation, and to convey personal imprints in the foods they prepared.
Although the term molecular was very fashionable in the 1990s, some chefs were not at ease in giving such a chemical meaning to a science associated with gastronomy. The "Research Chefs Association" (RCA) in the United States introduced the term “Culinology” (now a registered trademark) to describe “… the blending of culinary arts and the science of food.”
GASTRONOMIC ENGINEERING
Only in the last 20 years has the study of foods as materials become a field in its own. This maturation has been fostered by integrating progress in related areas, most notably, polymer science, colloidal science, mesoscopic physics, microscopy, and other advanced instrumental techniques, and by applying it to food structuring (Aguilera and Lillford, 2008). The battlefield of definitions and scopes in modern gastronomy is expanding.
Food material scientists have created the term gastronomic engineering (GE) which is “… applying concepts of food materials science as well as methods and tools of food engineering to guide the physical and chemical transformations of culinary practice and design novel structures that, according to chefs, are uniquely tasty and palatable” (Aguilera and Lillford, 2008). It is clear that chefs are central in the process of creating food structures. They actively participate in the generation of ideas, process development, and final applications. Examples of novel engineered structures already established in modern cuisine are edible films, the airs or three-dimensional sauces, gel beads, and textures derived from the use of cryogenic freezing, just to name a few.
GE also encompasses the principles of engineering that lead to the formation of food structures. Cooking is largely transferring energy to heat a food so it changes in texture and flavor, becoming edible. Broiling, boiling, baking, steaming, and frying are the terms used by cooks that describe different methods to affect heat transfer. Cutting, dicing, grinding, and mashing are all size reduction operations that are well defined in engineering texts. Stirring, shearing, and mixing are based on the transfer of momentum to liquids or particulate materials, and so on. Heat and mass transfer concepts as well as the physical chemistry behind food processing and microstructural changes in foods are presented in the book by Aguilera and Stanley (1999).
INGREDIENTS FOR STRUCTURE DESIGN
For example, while traditional gastronomy for the most part used one thickener (starch) and one gelling agent (gelatin), today’s chefs use a myriad of hydrocolloids and refined proteins in order to control the viscosity and mouth feel of their dishes. Commercial kits containing standardized thickeners and gelling agents for culinary applications based on hydrocolloids are already in the market. Among these different products we find
1. Agar agar: A polysaccharide extracted from the algae Gracilaria, traditionally used in Japan (known as kanten) for molded jellies and in microbiology laboratories. Hot solutions at very low concentrations form strong gels when cooled to room temperature.
2. Carrageenans (kappa, iota, and lambda): A family of linear sulfated polysaccharides extracted from red seaweeds (e.g., Chondrus crispus) that have been used as food additives for hundreds of years. Used as a thickening, stabilizing, or emulsifying agent in dairy products, reprocessed meats, and to make puddings, salad dressings, etc.
3. Egg white powder: Spray dried egg whites that can be used in the same preparations as regular egg whites to achieve more concentrated flavors, new textures, and foams.
4. Gellan gum: A bacterial exopolysaccharide that may form hard and brittle gels that crumble in the mouth, giving a “melting in the mouth” sensation.
5. Guar gum: Primarily, the ground endosperm of the seeds from Cyamopsis tetragonolobus (L.) Taub. (Fam. Leguminosae) mainly consisting of high molecular weight (50,000–8,000,000) polysaccharides composed of galactomannans.
6. Methyl celluloses: Water-soluble cellulose ethers derived from cellulose. They have been used as binders, emulsifiers, stabilizers, suspension agents, protective colloids, thickeners, and film-forming agents for many years. Form gels upon heating and return to solutions after cooling.
7. Sodium alginate: A seaweed extract from the giant kelp Macrocystis pyrifera. It is a cold gelling agent in the presence of calcium (i.e., a solution of calcium chloride), and is used to make artificial caviar (“spherification”) and other gels.
8. Whey protein isolate: Manufactured from sweet dairy whey and spray dried. Used as a protein source and to form gels by heating.
9. Xanthan gum: Polysaccharide gum made by a fermentation process using Xanthomonas campestris, widely used as a natural thickener and emulsifier, and a substitute for eggs and gluten. It reduces the thinning of liquid films in foams.
As food scientists will recognize, some of these ingredients have been used for centuries. Their traditional applications are well established and most of them have been amply researched by academia and the food industry. The point is that their adoption by chefs has been fast and steady. An excellent practical example of converting ideas from the chef’s mind into actual products using physicochemical principles and some of these ingredients is presented by Arboleya et al. (2008). A bubbly beetroot juice (thin foam) was stabilized with a mixture of egg white powder and xanthan gum in order to trap the aroma of the food. An edible film was obtained by the casting method, using a solution of gelatin extracted from cod skins. The idea was to fool the sense of vision and taste by covering the pieces of white fish with an artificial skin.
FOOD STRUCTURING: KNOWLEDGE OF MOLECULES TO PRODUCTS
Our understanding of how food structures are built from the molecular level to the macrolevel has advanced steadily in recent years. For a more detailed description of the science behind food structuring, the reader is referred to the book published by Aguilera and Lillford (2008). It is a characteristic of foods that several structure building phenomena occur simultaneously at different length scales from the molecular level to the macrodomain. Furthermore, thermal gradients build up during heating that lead to heterogeneous and composite structures. Examples of the former are bubble growth and gluten setting during baking, and of the latter, the formation of crust in fried and baked products. Some specific phenomena leading to structure formation in foods are
1. Stabilization of interfaces by small molecules (e.g., emulsions)
2. Formation of liquid crystalline phases
3. Denaturation of proteins
4. Aggregation and phase separation of macromolecules
5. Hydration and swelling of starch granules
6. Assembly of colloidal networks of proteins and polysaccharides (e.g., gels)
7. Formation of fat crystal networks
Control of food microstructure starts at the molecular level. Food chemists continually modify the molecules for added functionality (e.g., modified starches) and of course, safety. The next level of organization is the assemblage of molecules at the mesoscale (10 nm–1 mm). Further up in the scale is the realm of polymer physics where interactions of molecules give rise to phenomena such as growth of separated phases (crystals, bubbles, droplets) and formation of amorphous matrices that stabilize the product in a metastable state. The last level is performed directly in the kitchen.
WHAT SEDUCES INNOVATIVE CHEFS?
Nine of the more popular concepts that attract the attention of modern chefs are:
1. Converting liquids into light three-dimensional structures, e.g., foams
2. Entrapping natural aromas distilled in the laboratory and smoke from indigenous woods
3. New gases and aromas to aerate solutions and solids
4. Entrapping solutions in the solid state as gels
5. Forming transparent films
6. Structures formed by freezing with liquid nitrogen
7. Cooking meats and fish under vacuum at low temperatures and for extended periods of time
8. Development of crispy, crunchy, and crackly textures
9. Teasing and astonishing people, with new sensations (e.g., explosive candy)
As pointed out by Vega and Ubbink (2008), it is ironic that both scientific knowledge and technological concepts originally developed for industrial food production, including those described in patents, are adapted and used to their advantage by the practitioners of scientific cuisine.
CHEFS AND THEIR LABORATORIES
Most reputed chefs involved in scientific cuisine have their own laboratories, or command outsourcing from independent entities (e.g., AZTI-Technalia). For example, top chefs Ferrán Adrià and Heston Blumenthal have research laboratories and staff dedicated almost entirely to the creation of new dishes and techniques. It is well known that scientist Hervé This and chef Pierre Gagnaire have been collaborating for years.
Sophisticated techniques such as rheometry to characterize semisolid foods or gas chromatography-mass spectrometry for aroma research are not uncommon in well-equipped laboratories. Some sort of pilot facility to mimic reactions, extraction processes, blending and drying operations is now necessary for gastronomic research. Precise analytical instruments are compulsory to measure critical parameters that define product specifications, such as refractive index, specific gravity, moisture, acidity, etc. (McEvoy, 2005).
The Arzak Laboratory, located near the restaurant and operational since March 2001, combines modern equipment and a team of “alchemists” who are indispensable to generate the dishes for a kitchen that does not abandon tradition. The “bank of flavors” includes more than 1600 flavors from around the world that are carefully sorted and classified, normally applied to some dishes or ready to be introduced into new developments (Gastronomía and Cía, 2008).
At The Fat Duck, they have developed an internal computer-based encyclopedia (duckopedia) that serves as a virtual laboratory notebook where all the procedures, results, and conclusions of their culinary experiments are registered. Blumenthal has published a book where he explains the chemistry and physics behind cooking to college students and the general public. At elBulli, all creations are systematically cataloged by grouping them into families, in order to better understand the fast evolution of their innovative cuisine (Vega and Ubbink, 2008). Adrià is also the president of the Alicia Foundation created by the Generalitat de Catalunya and Caixa Manresa, which owns a modern laboratory installation located in Sant Benet de Bages since October 2007.
NEW TOOLS AND EQUIPMENT
Commercial appliances to cook under vacuum (sous vide) and at low temperature are becoming standard equipment in restaurants to tenderize meat and fish in unique ways while intensifying flavors as the food cooks in its own juices. The same device can be used to impregnate solid foods with the surrounding solution and to achieve uncommon combinations of familiar textures and exotic flavors.
Chef Homaro Cantu of Moto restaurant in Chicago is recognized by his creativity in implementing new devices. He has modified an inkjet printer to print the menu on an edible paper with various tastes using vegetable inks (that is later eaten by the customer; Lee Allen, 2005). Another favorite tool used by Homaro Cantu is a laser, similar to the type used for eye surgery, which he uses to vaporize bits of cinnamon or vanilla (Thorn, 2007).
WORKING WITH CHEFS
The author has had the experience of working with a young chef for the last 3 years. Chef Rodolfo Guzmán, trained at the Mugaritz in the Basque country (number 4 restaurant in the world, uses the laboratory to develop some of his creations. Winner of numerous national awards in gastronomy, including Most Innovative Chef 2007, after opening Boragó in 2007 he has been involved in extracting aromas from flowers, structuring with liquid nitrogen popping out of Andean cereals quinoa and cañihua, and toying with edible films. Working with chefs presents several advantages for the food technologist, and no disadvantages, as least thus far. In this unique experience of product development we have realized that modern chefs are eager to know the scientific and engineering concepts behind their creations, even the technical vocabulary (apparently to make a distinction with traditional chefs, making them a “breed apart”). Once results are attained, their innovations are rapidly converted into dishes.
The market is well defined (customers of the restaurant), and cost is not a major restriction since these costs are passed on to customers. No major scale-up into industrial production levels is needed. For example, on only a couple of dozen portions may be prepared daily with laboratory-size equipment in the kitchen. Also important is that restaurants have been free till now of some of the regulations (e.g., labeling ingredients) and inspections required for industrial production of foods.
Another major plus of working with chefs is that they are very credible to the general public. Examples of this can be seen from the numerous TV shows all around the world. Chefs can pass on to people the science behind cooking with minimum distrust, which is not the case of the food industry, always suspected of deceiving consumers by using unhealthy additives and unidentified generic ingredients (e.g., ground meat from unknown species and GM foods).
SEIZING THE MOMENTUM OF SCIENTIFIC CUISINE
It is obvious that a limited proportion of consumers have access to top restaurants and to experience the novelty of scientific cuisine. In time it is expected that lesser quality restaurants and perhaps, food chains will benefit from the “trickle down” of these innovations. Meanwhile, product development centers of food multinationals are listening to chefs and bringing them into their quarters to profit from their approaches. As the use of new products become more popular and disseminated in the general public, ingredient companies will find expanding niches for their products. Manufacturers of kitchen appliances are likely to see expanded opportunities as the precise control of heating, cooling, mixing, and shearing during cooking becomes a must in achieving unique gastronomic results. Food product developers should be alert about this top–down trend of innovation as it may lead to improved goods with added novelty. Top chefs excel at disseminating their creations in books, Web pages, and TV shows. At the end of the day, most of the developments of scientific cuisine have been picked up from the published scientific literature.
CONCLUSION
By Jose M. Aguilera in the book "An Integrated Approach to New Food Product Development", edited by Howard R. Moskowitz, I. Sam Saguy, and Tim Straus, published by CRC Press- Taylor & Francis Group U.S.A, 2009, excerpts from the pages 318 to 327. Adapted and illustrated to be posted by Leopoldo Costa.
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