Sterilizable Fluidized Bed Fermenter - Assignment Example

of the paper s Introduction: Fermentation refers to the process of converting carbohydrates to alcohol and carbon dioxide by the fermenting action of microbes such as yeast, bacteria or combinations of different microbes. Fermentation usually implies that the action of microorganisms is desirable. Zymology is the science off fermentation and the study of fermentation techniques and principles. The term "fermentation" is sometimes used to specifically refer to the chemical conversion of sugars into ethanol, a process which is used to produce alcoholic beverages such as wine,  beer, and cider. Fermentation is also employed in the production of bread (CO2 produced by yeast activity); in preservation techniques to produce lactic acid in sour foods like acidified milk, sour food, and yogurt. Fermentation is an important method that is sued in different food industries such as in the winery, bakery or dairy industries. Commercial fermentation calls for usage of different equipments since the processes require maintenance of the right temperature and ambience for optimal activity of the microorganisms used. Winery: The making of wine-making may be considered almost a form of art. The different textures and aromas that are obtained are all results of a wonderfully maintained process which requires acute precision at every single stage. Yeast strains are used for fermentation and Non-Saccharomyces cerevisiae yeasts are being used more prevalently in the industry to add greater complexity to wine because of their oenological properties (Cianni & Maccarelli,1997). During wine making fermentation induces conversion of juice of the grapes into an alcoholic beverage. During the procedure, yeasts that are added to the grapes, transform the fruit sugars present in the grape juice into ethanol and  carbon dioxide (as a by-product). In winemaking, the temperature and speed of fermentation are important considerations, while the level of oxygen present is also an important factor at the starting point of the fermentation. To ensure that the wine is produced with the right taste, aroma, texture and quality different equipments are used by commercial industries. Temperature maintenance is one of the most critical technical requirements of wine making. It allows production of higher volumes of wine while keeping the quality of the wine intact. Cooling is also required at different steps of the wine making process. It is accomplished by using chillers of different types. The most important element of such cooling devices are heat exchangers which allow transfer of heat from one point to another in any liquid. Cooling during Crio-maceration-Use of Heat exchanger Crio-maceration is a process during which the fresh grapes are macerated to produce musts which contain grape pulp. Cold maceration technique has been used for many years in the process of white wine making and it has been seen that cold maceration enhances and preserves the “intrinsic quality of grapes resulting in higher quality and characterization of the wine” (Parenti et al,2004), thereby increasing the commercial value of the final product that is obtained. In this cooling procedure cooling is done using heat exchangers. Heat exchangers used in this case is a tube-in-tube made of made of stainless steel. This kind of heat exchanger allows exchange of heat between two different liquids. A tube-in-tube heat exchanger consists of a tube inside another tube i.e., at least one tube pair is present even though more than one pair is also used , two tube sheets that are spaced apart, two annual flow chambers and two inner tube flow chambers. While the heat exchanger is being used a liquid flows through the inside of an inner tube while another liquid flows through the outer tube. The direction of flow of both the liquids is opposite in direction. This allows for the cooling of the macerated grapes at a fixed temperature to ensure that the flavor of the grapes is not lost. Cooling during Fermentation-Use of coolers Production of good quality wines calls for maintaining the correct temperature at different stages. This is because each stage of wine making is done at different temperatures for the purpose of which different coolers are used. Glycol chillers are one of the coolers that are prevalently used for the purpose of maintaining low ambient temperatures. Glycol coolers are easy to use and handle. They require a coolant, a liquid load (wine in this case) and an electrical power supply source. The coolant used in glycol coolers is propylene glycol which is a kind of food grade antifreeze. Glycol mixed with water allows the temperature to be brought down to almost 25-27 degree Fahrenheit. The control of temperature in this case is done by the help of tiny microprocessor-controlled instruments. These controlling instruments are primarily responsible for the maintenance of temperature. Fermentation tanks or bins Fermentation tanks or bins play an important role in the entire process; they primarily support the conversion of sugars in the grapes to ethyl alcohol. Wine tanks are basically made up of stainless steel. There exists a main tank for holding must of the grapes and an upper tank that is placed right above the main tank. A supply of the grape must from the base of the main tank to the upper tank is ensured by a valve apparatus. An actuator apparatus, which is electromagnetically operated, is connected to the valve apparatus. The wine is put in these tanks for fermentation along with the inoculum of yeast. In some cases plastic tanks are also used but this occurs in smaller wineries. Such tanks are made of food grade plastic, which is permeable to oxygen as well. Fermentation Bottles Using bottles as equipment for fermentation is known as bottle fermentation. In this, a bottle is taken as the vessel which holds the wine and the yeast together for 1-3 years. The wine inside the bottle is slowly fermented in this process. The autolyzed reactions taking place in the undisturbed bottle ensures addition of special flavors. Conical fermenters Conical fermenters are basically cone-shaped. It is made of food grade stainless steel. These tanks have a conical shape, with a dish-like top and almost cylindrical body. The bottom of the tank is set an angle of 60 degrees which allows for optimal fermentation. The conical tanks have their own cooling system which is made up of a jacket filled with polyurethane. The inside of the tanks are sanitized and polished while the outside of the tank come with a mirror finish to ensure minimal loss of temperature to the surroundings. Spontaneous fermentation To obtain a thorough understanding of cultured yeast, it becomes necessary to understand their counterparts as well-spontaneous fermentations. Some consider spontaneous fermentations as an advantage especially in the wine industry. However, there are two myths involving them that are needed to be addressed. Firstly, all the yeasts that work during a spontaneous fermentation come from the vineyard. The second is that indigenous yeasts (mostly of the Kloeckera, Candida and Hanseniaspora genera) are able to finish fermentation to dryness. The University of Geisenheim has recent studies that prove that the vast majority of yeasts in a spontaneous fermentation come from the winery (from last year’s fermentation) and not from the vineyard. Those studies also show that the yeasts that finish the fermentation are from the Saccharomyces genera (or strains of closely related species such as S. bayanus), as aciculate yeast species are only viable until alcohol levels reach around 4% (or must density drops to 1.070–1.060). Also, a dominant strain of Saccharomyces (based upon growth factors, genetics, timing and killer factors) will take over the fermentation and colonize the winery. This strain will finish the fermentation. Dairy Industry Fermented dairy products are made from milk of almost all domesticated milch animals since ages. Several new types of fermented milk products are becoming popular all over the world. The traditional fermentations take place as a result of the activities of natural flora present in the food or added from the surroundings. Dairy products, represent a major portion of the total European functional food market, and are at the forefront of probiotic developments (Miller et al., 2000). There are numerous dairy products, the productions of which follow different procedures and temperatures and calls for usage of different equipments as well. For example, for yoghurt production the milk is first heated to about 80 °C (176 °F) to kill any undesirable bacteria and to denature the milk proteins, so that they set together rather than forming curd. The bacterial culture is added, and the temperature is maintained for 4 to 7 hours to allow fermentation and yoghurt production while in case of kefir production fermentation lasts around 24 hours and requires a temperature of around 68–77 °F. Fermentation tanks: One of the most basic equipment that is used in the dairy industry is the tanks used for the process of fermentation. Fermentation tanks are usually used for production of yoghurt in an ambient environment. The design of a normal tank employs usage of sterile air which is kept under high pressure to inhibit entry of harmful or unwanted microbes from the outside in to the fermentation tank, while the milk is being fermented. The tank is usually made up of stainless steel and contains stainless steel blades which are used for continuous stirring and mixing and helps regulated the flow of the milk and the yoghurt. The tank also uses heat exchanger mechanism to allow maintenance of temperature since very high or very low temperature would stop the entire process of fermentation of milk. Another kind of fermentation tank that is sued is known as the bulk fermentation tank. In large industries the fermentation tanks are fitted with temperature and pH-recorders. Bulk fermentation tanks are designed in a conical shape so that the fermented yoghurt is discharged more easily from the base. During incubation period warm water is made to flow through the water jacket of the equipment (Yildiz). The temperature of the water is warmed at 40-45 degrees. Right after the product is warmed the coagulum is cooled. The fermentation tank has air filters which stops large particulate matter from the entering the tank and contaminating the product. Kefir is yet another dairy product which needs to be fermented well. Glass is the most widely used material and kefir fermenters are mostly made of glass. Glass is used as the culturing containing since it does not react with the brew that is placed inside the container. Fermentation of yoghurt is done by adding stabilizers, flavors and bacterial culture and another unique fermenter that is used for this purpose ensures that the quality of yoghurt produced is optimum. The fermenter basically consists of a condenser which helps to bring the temperature of the homogenized and pasteurized milk to about 109-114 degree Fahrenheit. The bacterial culture is added here. A double jacket is present around the whole structure, which ensures that none of the heat is lost during the process of fermentation and stabilization. Cooling pr and post -fermentation-use of plate heat exchangers During fermentation the product acquires great flavor and texture and the product needs to be rapidly cooled to keep these intact. The rapid cooling is achieved by using plate heat exchangers. The first of plate heat exchanger consists of a number of plates. The continuous series of the plates that are used helps in controlling and regulating the temperature of the fluid in process Another kind of heat exchanger that is used consists of an extremely modulated design. The design allows the existence of wide gaps which do not have any contact points. The surface area of the plate is almost 3 meter squares and is above welded cassettes of steel. The design works on the principle of decreasing the pressure drastically thereby increasing the temperature of the milk inside. The third type of heat exchanger that is used is a double walled one. The design of this plate heat exchanger consists of two thin plates which are separated by a small gap. The structure has two opening-an inlet and an outlet. The openings are welded and the rest of the structure of the double walled heat exchanger remains the same when compared to conventional ones. Rapid cooling of the product is done when it enters from the inlet tube and exits from the outlet tubing. BAKERY INDUSTRY The bakery industry involves usage of microorganisms since fermentation is the most crucial part in any kind of baking. Yeast is the most important microbe used in baking industry. In the process of fermentation, yeast produces carbon dioxide, alcohol and other compounds which enable dough to rise and modify its physical properties. When the fermentation is correctly achieved, depending on the quality of flour among other things, the baker will obtain the proper external and internal characteristics (grain and texture) suitable for a determined finished product. Together with alcohol, a small amount of other volatile compounds are released. These are involved in the original taste and flavors of baked leavened products. Most of these compounds, and all of the alcohol, evaporate when baked. Yeast needs the right temperature to be able to help the dough rise and make the product rise. The right temperature in the commercial industry is achieved by a number of different equipments. Fermentation Tank system Sour dough needs to be fermented well before the dough can be utilized for any purpose. Most fermentation tanks utilize the famous Ankerbrot-Reimelt system and Paech-TUB system each of which allows the fermentation time to decrease and are sophisticated as well (Kulp & Lorenz,2003).These fermentation techniques are basically employed in Germany. The Paech-TUB system is widely used for fermentation of dough and utilizes different equipments. The fermentation tank has temperature controllers and the approximate volume of each tank is 2 m3. The system primarily consists of two different fermentation tanks and an insulator and a heat exchanger as well. The heat exchanger is present right after the first fermentation tank. The fermentation tank includes a stirrer which has been placed to easily pick out the cooled dough since cooled dough is not as mobile as the fermented dough (Kulp & Lorenz,2003).. This primarily because cooled dough has high viscosity and density. The second fermentation tank is a segmented one. The segments are filled form the above and emptied from below. The primary process is to allow the dough to pass to the first fermentation tank after which the dough is cooled in by the heat exchanger. The cooled dough is then stored and passed off to the second fermentation tank where the dough is ripened before usage in baking. Fermentation Tanks Stainless steel fermentation tanks are utilized in case of cheese production, cream and cream cheese production. The stainless steel tanks are maintained under pressure which is about 0.4 bar. The tanks are insulated so as to control the loss of heat by insulation. However, if needed the tanks maybe equipped with thermal double jackets as well to maintain the accurate temperature as well. Stainless steel blade stirrers are present inside each of the tanks to ensure continuous, rapid and homogenous stirring of the products. The stirrers are oriented straight at about 90 degrees and each stirrer has helical blades made of steel. These mechanisms ensure that the product is pumped thoroughly and optimally. Yeast strains are added to the product for proper mixing and proofing. Baker’s yeast strains have been thoroughly researched upon and dealt with, to a great extent. The focus of the research was mostly to develop strains that acted rapidly as well as those that can easily adapt to various different baking processes.  If sucrose has been incorporated into the dough, it is immediately transformed by a yeast enzyme, invertase; into glucose and fructose (the two basic links composing sucrose are thus separated). When sucrose or glucose is added to the dough, they are directly fermented before maltose. This means that in such dough, mainly sucrose or glucose are consumed by the yeast. These sugars do not contribute to giving the bread a sweet taste since they are partly consumed.  Nutrient fed fermentation tank Nutrient fed fermentation tanks primarily are used to culture yeast for dough making. These tanks are made of steel and have tubes at the bottom to allow entry of air into the vessel. The rate of airflow can be controlled and is slowly regulated with the help of a stopper apparatus. Casks in the huge fermenters have worts which cause the added yeast to multiply rapidly and by the end of fermentation process the yeast cells grow almost 10 folds. Sterilized fluidized bed fermenter This new technology is utilized to ensure that the fermentation is carried out under low-moisture conditions. The fluidized bed fermenter consists of a heavy bottom with an orifice. This orifice is used for gas introduction and distribution. Filters are also present which helps separate used culture. The fermenter also uses an air humidifier which helps the fermenting microbes remain alive (Bucholz et al, 1988). Conclusion Equipments in any industry ensure proper maintenance of culture, temperature, texture, flavor and the quality of the products that are being produced. Different industries employ different kinds of fermenting machinery or machinery system to help them achieve and produce quality products. Basic fermenting tanks are used in industries which need fermentation and technological advancements and modulations have been done on the basic structure to achieve optimal fermentation that is fit for every individual product. References Bucholz et al. Sterilizable fluidized bed fermenter.(1988).Retreived from http://www.google.com/patents/US4746615. Ciani,M.& Maccarelli,F. Oenological properties of non-Saccharomyces yeasts associated with wine-making. World Journal of Microbiology and Biotechnology.1997.14(2):199-203. Kulp,K.& Lorenz,K.(2003). Handbook of Dough Fermentations (Food Science and Technology).USA:CRC Press.Print. Miller, G.D., Jarvis, J.K. and McBean, L.D. 2000. Handbook of dairy foods and nutrition. 3rd ed. CRC Press, Boca Raton, FL.  Parenti et al.(2004). Effects of cold maceration on red wine quality from Tuscan Sangiovese grape. European Food Research and Technology.218(4):360-366. Yildiz,F. Development and Manufacture of Yogurt and Other Functional Dairy .(2010).United states of America:CRC press. Read More