“Home cooking” is synonymous with rich, flavorful, and hearty dishes. The culinary world is embracing all that this segment has to offer, as exhibited by the rise of comfort foods, such as fried chicken (remade “boutique” style), macaroni-and-cheese (with gourmet versions now ubiquitous), and the rising popularity of Indian and North African cuisine – known for their slow-simmered, fragrant and saucy dishes. It’s safe to say that slow-cooking quickly is becoming a menu staple across the board.
Part of the trend is owed to a backlash against decades of lackluster, low-fat, bland diet foods. Today’s consumer choices indicate a demand for flavor and value that is unrepentant.
Another aspect is that, during stressful economic times, people seek comfort, and slow-cooked food equals comfort on a fundamental level.
With the arrival of the “foodie” movement, romanticized descriptions of food have become almost as important as the dish itself. Words like “succulent,” “robust,” “slow-roasted,” and “simmered” can be seen even in the health food sector. Consumer awareness of food ingredients and additives has never been higher, and the food industry is actively capitalizing on associations with the home-cooking “edge.”
The authenticity of slow-cooking stirs up thoughts of bold flavors, hearty dinners, luxury...and time.
Convenience has become such a necessity that slow-cookers, once lauded as the ultimate time savers in the preparation of a home-cooked meal, have become cumbersome and obsolete in favor of Ready to Eat (RTE), proportioned heat-and-serve meals in the home.
The RTE supermarket business has exploded with myriad flavors, protein and carbohydrate combinations, ethnic offerings and dietary restriction-compliant offerings. Even restaurant chains capitalize on the popularity of this segment, with “blessings” from celebrity chefs and co-branding attached.
The ability of foodservice and retailers to meet the demand for these boutique offerings requires no small feat of development and engineering.
Hurry Up and Wait
When meat products are subjected to heat, the proteins in the muscle and connective tissue begin to undergo denaturation. With insightful comprehension of this process, the conformational changes that result can be used to the product developer—and consumer’s—advantage, to create a mouth-wateringly delicious product.
Meat, of course, is muscle tissue. Each muscle cell is sheathed in a collagenous membrane, and several cells are bundled together, encased in another collagenous membrane.
It is this collagen that plays such a large role when cooking animal proteins. The duration of time exposed to heat, as well as temperature, will determine the organoleptic and textural properties of the final meat product. At 160°F, collagen proteins begin to break down into gelatin. Collagen is tough and chewy, and typically avoided on most plates, whereas gelatin is rich, soft and easy to eat.
The ultimate goal in cooking tougher cuts of meat is to break down this collagen and create gelatin proteins. At 140°F/60°C a cook ends up with a rare steak; it is still juicy. Shortly thereafter, the collagen proteins begin to shrink and squeeze out some liquid, drying out the cut of meat and making it slightly tougher. At 167°F/75°C, the steak is now well-done, and much of the liquid in the original cut has been ejected by the collagen proteins. The expulsion of liquids causes a deceleration in cooking time, so precision and patience become key.
The slow-cook process allows a longer time period for the meat product to cook and attain temperature. Once the product has reached 194°F/90°C, all of the collagen in the connective tissue of the muscles has now broken down into gelatin, and there is nothing left to keep the muscle fibers together. The result is a cut of meat that can be easily pulled apart, and easily piled on to a bun for, say, a nice pulled-pork sandwich.
Traditional kitchen techniques of improving meat tenderness can be implemented in large-scale processing, both prior to and post cooking. They will yield the most desirable finished product by minimizing drying and promoting muscle fiber breakdown.
The best-known home method is that of “mechanical tenderization”—beating the meat with a tenderizing hammer. Although effective, such physical tenderization is not always feasible in large volumes.
Marinades are meat tenderization methods employed prior to cooking. The meat is immersed or coated in solutions with an acidic liquid base, typically vinegar, wine or juice; or fermented (thus also acidic) liquids or semi-liquids, like buttermilk and yogurts.
Marinating promotes tenderness by weakening muscle tissue and increasing the protein’s ability to retain moisture. The process also slows spoilage, by reducing the pH and inhibiting microbial growth, while promoting flavor via the acidic compound and any other flavoring agents present in the marinade.
A drawback to marinating in batch processing is that it can take anywhere from hours to days, so the industry has developed methods of increasing marinade efficacy. The most efficient marination-expediting method is vacuum-tumbling. Marinating via this process on an industrial scale most often is used in concert with functional ingredients, such as phosphates.
“Techniques for incorporating phosphates include injection, followed by vacuum-tumbling to promote even distribution of the injection solution throughout the pieces of meat,” explains Luciana Lampila, PhD, RDN, CFS, as well as food phosphates consultant for the Food Safety Institute in Baton Rouge, La. Lampila warns, however, that, “Injection in the absence of tumbling can result in ‘pickle pockets’—areas where the solution dissolves the connective tissue and protein—leaving holes or voids in the muscle.”
“Research has shown that phosphates can be used to raise the thermal transition temperature in beef homogenates,” elaborates Lampila. “This translates to greater thermal stability of the water-binding protein, reducing moisture loss during cooking.” Lampila points to sodium tripolyphosphate (STPP) as one solution. “STPP is hydrolyzed by enzymes present in the meat in a way that increases binding capacity of both protein and water.”
Lampila adds that, in the absence of phosphate, at pH 6.0, moisture loss increased 1% for each degree over 52˚C/125°F. “Thus, the presence of phosphates in cooked and slow-cooked meats is directly related to the succulence of the finished meat product.”
Salt and Enzymes
Meat-tenderizing enzymes play a substantial functional role in processing. Commonly used enzymes can be extracted from a number of plants including papaya (papain) and pineapple (bromelain), and are commercially available in their native or purified forms. The majority of enzymes employed in this function are most effective at temperatures between 140°F and 160°F/60°C to 70°C, so the majority of protein “digestion” occurs during the cook step.
Care must be taken during processing to time the tenderization processes appropriately, as improper application of enzymes can yield a product overly digested on the surface, while remaining raw internally.
Brining also is an effective method of tenderization. Brine is typically 3-6% salt by weight, and is slow-acting, making it similar to a marinade.
The main purpose of brining is to increase the juiciness of the final product, and the first step is to disrupt the muscle structure. “Historically, NaCl was used in many meats at a level of 3-5%; however, with the use of the condensed phosphates at a level of 0.5%, the NaCl level can be reduced to 1.4-1.8%,” explains Lampila. “In addition, NaCl promotes the oxidation of lipids under some conditions.” This helps allow for reduced-sodium labeling for some products.
“The presence of STPP not only protects against the oxidative effect of NaCl, but inhibits the development of ‘warmed-over’ flavor caused by iron-induced oxidation of lipids,” adds Lampilla.
Vegetables and starches act in quite a different manner when undergoing heat treatment for long periods of time. The carbohydrate compounds that make up the base of both vegetables and typical starch side dishes are primarily composed of glucose, fructose and fiber.
These sugar and fiber molecules are linked together in varying conformations to form amylose and amylopectin, which in turn are chained together to form starches. Starch molecules can absorb a large volume of water, and the starch granules swell with this water, causing a thickening effect to the liquid.
This process can be beneficial, as the starches that leach from the food will help to create a cooking sauce within the meal. However, time is crucial, as many starches will break down completely with extensive heat treatment. The starch granules absorb too much water and burst, and the starch molecules themselves begin to degrade.
The other components of a vegetable, such as the cellulose, will dissolve with heat and no longer support the cellular structure. This causes softening of the vegetable. In many cases, such as hearty stews, this can be beneficial. However, in soups—where heavy particulate is an important aspect both visually and in terms of texture—the integrity of the vegetable is preferred intact.
Maintaining structural integrity remains a major challenge when combining unique ingredients with variable cook times and tolerances. Often, more delicate additions will be saved for the end, as adding the vegetables after the cook step will circumvent the majority of the harsh conditions. The inclusions can also be par-cooked separately to avoid breakage or disintegration during cooking, or even added at the post-cook stage, if food safety restrictions permit.
Manufacturers also can combat issues with inclusion damage and breakage by batching in smaller quantities. This will prevent continued heating post-cook. Different processing methods, such as kettle cooking, can allow for gentle heating and agitation of products while cooking, thus offering increased ease of production, as well as less physical stress upon the vegetable particulates.
Modified starches are used extensively in the food industry. Starches can be altered from their natural state in a number of ways, including pre-gelatinization, allowing them to hydrate immediately upon addition to water. This can aid in production or even eliminate the requirement for cooking.
Alternately modified cook-up starches gelatinize only upon heating and are similar to conventional, home-use food starch. This can be highly beneficial to facilitate ease of processing, functionality and often cost.
The ability to time heating, and subsequently thickening, allows for increased flowability and reduced pumping requirements, while paving the way for more ready ingredient incorporation into mixed liquid products.
Starches also can come into play in their more natural forms. Whole grains—very trendy for both their health halo and comfort factor—exude enough of their native starch into a slow-cooked formulation to hold textures of both sauces and particulates in place.
If using whole grains, sturdier forms, such as barley, brown rice and wheat berries, work well; they add both organoleptic characteristics, such as “chew,” and a meaty/nutty flavor. This makes them especially desirable in slow-cooked, vegetarian formulations.
The third macronutrient of importance in slow-cooking is fat. Fat components, especially solid fats, break down into smaller components with increased time and temperature. Saturated fats are the predominant lipid in solid fat items, such as butter and animal fat, whereas unsaturated fats are seen typically in liquid form, most notably oils. However, chemically refined oils are falling from favor, as consumers demand cleaner labels with more.
In creating slow-cooked or slow-cooked mimicking products, separation of fat can be a challenge. When solid fats separate, they leave hard, white nodules of fat throughout the liquid portion and adhere to the particulate portions of a formulation. Liquid fats separate and leave an oil slick that can be unattractive.
Since fat is a primary flavor carrier, simply removing the fat is not always the solution. In the case of savory products, emulsifiers for the sauce portion come in handy. An emulsifier in this case can be as simple as a roux of flour or other starch, such as the increasingly popular native starches. These will maintain flavor and texture, while countering any separation anxiety in the finished item.
With the breakdown of the food components a major challenge, product developers are discovering ways to mimic the beneficial aspects of the slow-cook process, without having to actually cook the product slowly.
In order to replicate the sensation of intense flavors and textures in new foods, and foods scaled up for production, manufacturers turn to yeast extracts. Yeast extraction occurs when the compounds within the cell walls of yeast are obtained, in liquid or dry form, to be used in food products. Yeast extracts aid in both flavor development and flavor enhancement.
The greatest benefit of adding yeast extracts arises from the high quantity of glutamic acid extracted. Glutamates deliver a savory, umami sensation, signalling such sensations on glutamate receptors located in the taste buds. This enhances the experience of the food being eaten. Umami is a key component upon which to focus when approaching the scale-up of slow cooked foods.
Yeast extracts often are included as ingredients to replicate several hours of simmering beef releasing glutamic acid compounds. They serve double duty, too, by hiding any off-notes from other additives that might be needed for expedited production.
Hydrolyzed vegetable protein also is used industrially to produce a similar result. The vegetable proteins are hydrolyzed using an acid in order to break down the protein into its amino acid components. Amino acids—including glutamic acid—are released.
Other flavor components can be used to enhance and intensify savory or umami flavors and add trendier flavor notes to long-cooked foods. Specifically, hot sauces are increasingly popular, especially vinegar-based chilli pepper sauces. They can add balance and intensity to stews and soups and put a little ethnic “bling” into the formula.
One powerful umami provider is soy, including soy-based sauces. These have been a mainstay for centuries in Asian cooking. However, many product developers are turning to soy sauces for non-Asian foods because of the ability of soy sauce and its derivatives to provide concentrated body and flavor. Of particular interest to culinologists are the newly developed, light-colored soy sauce products, which allow for a much greater variety of applications.
Upon recipe scale up, ingredients often are transformed from what one would purchase at the grocery store to what is purchased industrially. Even the fresh herbs that give such specific flavor and aroma to homemade meals, oftentimes are switched to dried herbs, if the product must undergo lengthy heat treatment. This often involves a compromise on certain unique flavor notes, especially for those herbs that do not translate readily to dried form when it comes to flavor preservation (think basil).
Fresh, frozen and dried herbs all are useful in varying ways, yet dried herbs are the most robust and can maintain their integrity when undergoing stress. Furthermore, the duration of time spent while cooking allows any water in the application to migrate to the herbs and rehydrate the cells, thus allowing for the late release of flavor compounds.
Dried herbs are certainly a less expensive way to achieve flavor, while diminishing the possibility of herb color darkening. They also mitigate the challenge of maintaining the integrity of an herb flake or leaf. But for those herbs that are altered irreversibly by the drying process, other formats can be better-suited. For example, the aforementioned basil can be substituted with a basil pesto, in which the olive oil-based paste holds the floral notes of basil, even through typical processing methods.
Ingredient selection is of utmost importance in home cooking and restaurant meals but is possibly even more important when scaling up recipes for mass production. “There are ingredients such as broccoli we would not usually choose for a slow-cooked meal,” says Arlene Karan, vice president of R&D at Campbell Co. of Canada.
“The vibrant color is not maintained over long periods of cooking time, and the distinctive firmness of broccoli disappears. Broccoli and other cruciferous vegetables are very high in sulfurous compounds, and enzymatic reactions with these sulfur compounds release a pungent and generally unpleasant odor that can increase over time,” Karan says.
To avoid off-flavors in the final product, Karan recommends root vegetables be used in place of broccoli or other vegetables that do not hold up so well through the cook/chill/reheat process. “Root vegetables will maintain their integrity with time, while enriching a hearty soup or stew,” she notes.
Legumes—especially beans—are another functional ingredient Karan recommends. Like hardier whole grains, beans will break down slightly and absorb liquid, creating a smooth, stew consistency. “Legumes also offer the benefit of high protein content and can help to bulk up a vegetarian option,” she adds.
Different varieties of pasta will hold up better under heat; nevertheless, it is not ideal for a soup that has been cooked for several hours.
Pasta need not be ruled out entirely, however. If pasta is to be included in a dish, it is possible to process the product in a high-temperature environment for a shorter period of time. Not all ingredients are suitable for the slow-cooking technique.
Play and Pack
The processing technique used by the food manufacturer, of course, plays a significant role in the outcome of the final product. This is even more applicable to the slow-cooking or slow-cooked appearing food product.
When possible, manufacturers may choose to spend several hours cooking a product, such as a stew, as opposed to simply faking it.
“Understanding the specific functionalities of [each step of our] different processing methods is an important step in the development of a new soup or stew product,” she explains. “When the product contains beef, for example, we would opt not to cook at a high temperature for a short period of time, but rather at a low temperature for a longer period of time. Both routes offer a commercially sterile final product, and yet the longer time period cooking allows the beef proteins to naturally break down and become much tenderer. This slow-cook technique also is beneficial for flavor development, as it allows the herbs, seasonings and other ingredients to marry.”
Karan adds that, although flavors might meld together well over time, a long cooking time also can negatively affect flavor in the final product. “In any slow-cook process, you do end up losing some flavor with time, as certain volatile components that carry flavor escape and are lost.”
However, Karan warns that, in some formulations it is possible to “over flavor” at the outset in order to compensate for, and in anticipation of, such losses. “Slow-cook sauces on the market today are created with a very intense flavor that might seem unbalanced, if one eats a spoonful before cooking. It is only with the long cooking time the flavors marry and mellow out, creating a desirable final dish.”
Packaging also can play a large role in the final product. “Mylar plastic, a type of polyester film, has been shown to be highly beneficial to RTE meals,” says John Kelly, president of Deer Haven Farms Inc. “The film aids in moisture retention and does not allow juices to escape, leading to a juicier and more tender product.”
Kelly explains that this specific polyester film comes in several different formats, catering to the desired final product and the most convenient form for the consumer. A meal tray covered with Mylar film begins as two pieces of sheeting that are melded together. At a high temperature, the internal pressure becomes too great, and the weld loosens slightly, allowing any excess gasses to escape.
“It is not a high-tech valve,” adds Kelly, “but this form of packaging utilizes simply the occurring reactions and allows the product within to cook at both low and high temperatures, and for long periods of time. The flavor of the meal is enhanced due to the aroma retention.”
Kelly emphasizes that ingredient selection is also important in relation to polyester film packaging. “With the addition of certain ingredients, such as seasoning and vegetable starches, the juice from the meat and the starch from the vegetables will create a sauce that develops organically.”
“It also can be advantageous to add a previously manufactured sauce to the meal within this package, as the high level of acid in the marinade or sauce will aid in meat tissue breakdown and enhance flavor,” adds Kelly. “Through an extended period of time in the oven, either at the consumer level or the manufacturer level, this type of packaging prevents the meal from drying out and can assist in the creation of the qualities of a slow-cooked meal, as desired by the consumer.”
The trend of comfort food and home-cooked meals geared towards time-stressed individuals, and with an eye toward convenience, shows no sign of slowing. Being mindful of emerging technologies in packaging, processing and ingredients allows developers to combat multiple challenges in commercialization of home recipes and stay ahead of the curve.
Liz Chan and Kirsten Benneter are research chefs/food scientists in new product innovation for Giraffe Food & Beverage Inc., (www.giraffefoods.com) in Mississauga, Ontario. They and the Giraffe team are specialists in creating private label, custom- formulated sauces, dips and dressings intended for both retail and foodservice. They can be reached at www.giraffefoods.com. Check out their previous feature for Prepared Foods, “Healthy, Convenient Meal Solutions (On the One Hand),” at http://bit.ly/1Ma3Azh.