Why do we cook foods? Our ancestors before the advent of fire were eating raw foods and many foods like salads are even eaten to day raw. Even there are people in some parts of the world who drink raw milk without pasteurization or sterilization. Therefore most foods, even clean and uncontaminated, can be eaten straight with least discomfort. However with the human civilization becoming more and more modernized, people slowly developed taste for cooked foods leading to a plethora of processed food products which have flooded the market attracting more and more customers. Heat processing is to day an inevitable step before food is eaten for a variety of reasons, most important of which is making the food safe without causing biological discomfort or various ailments associated with raw foods. Besides the modern man has cultivated a taste for cooked foods whether using hot water or baking process. While water cooking does not raise the temperature beyond 100C at the atmospheric pressure baking temperatures can be as high as 300C. Higher the temperature faster could be the cooking and vice versa.
Currently cooking does not take more than one hour as per the practices prevalent now and technology is ever striving to reduce this time as much as possible for saving time for the man who has less and less time for long duration cooking. Against this trend is the attempt to promote "slow cooking" that can take up to 10 hours under low temperature conditions. According to the proponents of this alternative, slow cooking gives a better food and saves energy. Slow cookers generally use less electricity than the conventional cookers and can be used year-round. Because of the long, low-temperature cooking, slow cookers help tenderize less-expensive cuts of meat. They usually allow for one-step preparation; putting all the ingredients in the slow cooker saves time and reduces cleanup. Many foods can be cooked in a slow process including soups, stews, side dishes, main dishes, meats, poultry and desserts. Most slow cookers have two or three settings which can be adjusted for cooking times from 6 to10 hours. Setting the temperature at the higher level initially and then lowering the same can suit many foods to give a completely cooked taste. It seems an entirely new industry has been evolved for making slow cookers with different capacities and capabilities .
If clean cookers are used along with clean utensils and keeping the work area clean, finished products are always safe. . Of course perishable foods have to be refrigerated until preparation time. Meat cuts are to be thawed before putting in the slow cooker. As vegetables cook slower than meat and poultry, putting vegetables in first is recommended before adding meat and liquids such as broth, water or sauce. The cooker must be closed with a lid to get optimum results. While cooking, rarely any thought is given regarding the fate of nutrients present in the food because cooking is often conceived as a means of generating desirable flavor and taste. The perception regarding "desirable" eating quality traits may differ from society to society, country to country and ethnicity to ethnicity across the world. A simple example is that of milk. While Indians are used to "boiled" milk, western consumers want the milk just pasteurized with minimum heat exposure. Similarly there are hundreds of examples which substantiate the above diversity in the taste perception..
One of the reasons for over cooking in many parts of the world is the fear of microbial dangers coming from foods which are not properly cooked to destroy them and invariably people develop a taste for such foods over the years making it a standard practice. Time-temperature relationship vis-a-vis making a product sterile is well established and food technology has been striving for decades to reduce the exposure of foods to heat as much as possible. The HTST process and UHT process are able to achieve sterility within a matter of seconds while traditional method involved lower temperatures and longer heat exposure. Obviously modern technologies try to minimize heat damage and preserve the original quality to the maximum extent possible. Does the "slow cooking" method satisfy the palates of both Eastern and Western cultures? It is difficult to guess an answer to this critical question. It must be remembered that before the advent of cooking gas or electric stoves or ovens, in countries like India people were using fire wood and charcoal as fuels for cooking and invariably time taken can be long. As such there might not be any thing new in this so called "new" slow cooking system.
With the fuel cost going up, there are serious attempts to reduce its use as much as possible and save on the energy. Solar cookers are increasingly being used and naturally food takes much longer time to achieve the "doneness". There are also cookers which use a combination of heating and insulation to utilize the energy to the maximum extent without waste. Some consumers soak the foods like the grains in water over night before applying heat which saves significant amount of energy. As cooking is also a function of the water content in the food, soaking for 6-12 hours achieves saturated absorption of moisture into the food thereby enabling the heat to get transferred to the center of the material faster. Thus slow cooking is practiced in all countries even to day not for any reason of enhanced taste but for cutting down on energy use. Improvements in taste and flavor may be incidental here.
Science says that the food we eat contains many nutrients necessary to sustain good health and health pundits have laid down minimum and maximum levels of these nutrients to be taken every day for children, adults, men and women. Naturally if food is to be cooked to make it more easily digestible and eatable, we have to ensure minimum destruction of these vital components during the cooking process. Here again the sensitivity of different nutrients to heat varies enormously and a combination of air and heat can bring about greater destruction under common cooking conditions. From a nutritional point of view probably slower cooking can result in greater loss of nutrients thus lowering the overall nutritional quality. In this context modern cooking system will probably score over slow cooking mode. Ultimately the euphoria around slow cooking is bound to wane with time like it has happened with many fads previously!