ROLE OF FERMENTATION IN FOOD TECHNOLOGY



ROLE OF FERMENTATION IN FOOD TECHNOLOGYSUBMITTED TO: Sir Tahir Baig SUBMITTED BY: Ayesha SajidRoll No. 2731st December 201218669002458085 TABLE OF CONTENTS Serial icsPage No.1Introduction 12Classification of food fermentations1Lactic acid fermentation1Alcoholic fermentation 1Solid state fermentation23Type of food fermented 2Dairy products2Beverages2Cereal based foods3Meat products34Importance of fermentation in food industry3Flavor enhancement3Nutritional value4Preservation4Antibiotic properties5Alleviation of lactose intolerance55Conclusion 56References 6ROLE OF FERMENTATION IN FOOD TECHNOLOGY The production and consumption of fermented food date back to many thousand years with the evidence of fermentation of barley in beer. It is an age-old process in food biotechnology. Fermented foods are the ones that undergo microbial or enzymatic action in order to produce significant modifications in the food by biochemical changes (Campbell-Platt 1987). In fermentation organic substrates mostly carbohydrates are oxidized and act as an electron acceptor (Adams, 1990). In food processing, carbohydrates are converted to?alcohol, lactic acid, carbon dioxide (CO2)?or organic acids with the help of microbial organisms such as bacteria, yeast etc. in anaerobic?conditions. Processes involving the production of ethanol by yeast or lactic acid bacteria (LAB) producing organic acids are included in food fermentation.CLASSIFICATION OF FOOD FERMENTATIONSFermentation can occur spontaneously or can be induced. There are different types of fermentation used in food processing. Food fermentations can be classified either based upon categories, classes or commodities. Some examples of food fermentations are as follows:Lactic acid Fermentation In lactic acid fermentations sugars are transformed to lactic acid by lactic acid organisms such as Leuconostoc, Streptococcus, Lactobacillus bacteria. Lactic acid is the most important compound result from this reaction. Lactic acid producing bacteria are most significant bacteria used in food fermentation and production. Sour milk is one of the most ancient lactic acid fermented food in which the lactic acid bacteria will convert the milk sugar known as lactose to lactic acid resulting in sour or fermented milk. Dairy products for example yogurt, cheese, butter and sour milk are also produced. Lactic acid fermentation is used for the preservation of different vegetable foods (Steinkraus 1983). The best example is of sauerkraut, produced by the action of LAB on cabbage (Pederson and Albury 1969).Alcoholic FermentationThis involves the production of ethanol mostly by yeast or yeast like molds such as Amylomyces Rouxii. Alcoholic fermentation usually results in the production of beverages such as wine, beer vodka etc. and rising of bread dough. The substrates used for fermentation include honey, cereal grains, sap of palm, fruit juices, grain malt, that contain sugars that can be fermented and are converted to ethanol by yeast. During the process equal amount of carbon dioxide (CO2) is also produced as a side product and this process is carried out under anaerobic conditions.Solid state fermentationIt is a fermentation performed on a solid substrate acting both as support and nutrient source for the microorganism when there is no free flowing liquid (Pandey, 1992). SSF results in biomolecule?manufacture utilized in food. These biomolecules are?metabolites which are generated by microorganisms such as yeast or bacteria. This is an ancient process and different fungi are used in food production. The most common examples include the fermentation of rice and cheese by fungi. Industrial enzymes are produced commercially by SSF (Suryanarayan, 2003). TYPES OF FOOD FERMENTEDDifferent types of food are fermented and used daily in diet. Some examples of these foods are as follows:Dairy productsMilk fermentation and the dairy products manufactured in the process are extremely important for human beings. Dairy products like yoghurt, kefir, cheese, butter and sour milk are fermented. Fermented milk products are important source of probiotoics (Katz, 2001). A fermented milk product, yoghurt has the ability to modulate the immune system.BeveragesThe process of fermentation for the production of beverages has been used since old times. Fermented beverages are of two types:Wines produced by the fermentation of fruit juices having fermentable sugarBeers produces from the products containing starch which undergoes enzymatic splitting, malting and mashing so that the sugar become available to microorganism for fermentation.Cereal-based foodCereal grains have been human ancient source of food. Grains can be processed into food by fermentation (Akinrele, 1970). “Ogi”, cereal porridge is made from maize, millet and sorghum fermentation (Osungbaro, 2009). Most of cereal based foods are obtained from maize, wheat, millet, sorghum, or rice. Fermented cereal products can either be liquid or solids (stiff gels).Meat ProductsMeat is consumed worldwide however is greatly susceptible to contamination by pathogens. Therefore it is necessary to preserve meat and maintain its stability. This is achieved by meat fermentation (Hugas et al. 2003). Using lactic acid bacteria (LAB) for the fermentation of meat sausages preserve the meat and protect it from spoilage (Metaxopoulos et al. 2002). Fermented fish products can be stored for prolong periods by retaining their nutritional quality. More over different vegetavles, legumes such as soy products and tea, coffee are also fermented.IMPORTANCE OF FERMENTATION IN FOOD TECHNOLOGYFermentation gives physical and nutritional benefits to the food. Fermentation plays following key roles in food processing: (1) Enhancing a range of flavors, odor and textures of food(2) Food preservation through lactic acid, alcoholic, or alkaline fermentations (3) Increasing the nutritional value of food by producing different vitamins, protein (4) Reduction in toxinsFLAVOR ENHANCEMENTFermentation enhances the aroma and flavor of food. The organoleptic properties of fermented food make them preferable as compared to unfermented food products. The flavor of fermented food products is greatly influenced by acid fermentation as it produces lactic acid thus resulting in lowering of pH causing sourness in food. During fermentation, metabolism of sugar produces acid or alcohol thus decreasing sweetness (McFeeters, 2004). Lactic acid bacteria converts carbohydrates to organic acids and produces other flavoring compounds such as diacetly, acetaldehyde and ethanol contribute to the desired taste and flavour of the food Diacetly is a compound that gives butter milk and culture sour milk a sweet taste. Acetaldehyde is essential for characteristic yogurt flavor and aroma. During the baking of bread dough, a typical odor compound 2-acetyl pyrroline is liberated having an odor almost similar to popcorn. Its precursor is ornithine produce by fermentive LAB from free arginine (Schieberle 1995). NUTRITIONAL QUALITYMany food products have low nutritional value such as cereals but it has been shown that lactic acid fermentation enhances the nutrient content and digestive property of different foods (Nout, 2009). The quantity and quality of proteins and vitamins increases on the other hand antinutritional agents decreases after fermentation (Paredes-López & Harry, 1988). During the process of fermentation the raw substrate undergoes many soaking and hydration stages and then cooking many potent toxins such as trypsin inhibitors and cyanogens in cassava declines. Aflatoxins present in peanut and grains is decreased (Steinkraus, 1983a). Fermentation causes a decrease in the sugars and indigestible carbohydrates level in legumes thus leading to reduce abdominal pain (Matarjemi and Nout, 1996).PRESERVATIVE PROPERTIESThe preservative quality in food and beverages is due to antimicrobial metabolites formed during fermentation (Caplice and Fitzgerald, 1999). These metabolites include different organic acids such as acetic acid and propionic acid. Lactic acid bacteria inhibit the growth of pathogenic organisms through acid production which decreases the pH (below 4) during fermentation thus protecting the food from spoilage and poisoning (Ananou et al, 2007). Acids interfere with the maintenance of potential of cell membrane, inhibit active transport across membranes and inhibit range of other metabolic functions (Doores, 1993).Antifungal properties of lactic acid bacteria have been observed (Schnürer and Magnusson, 2005). Thus fermentation increases the shelf life of fermented food. Microorganisms produce variety of antimicrobial proteins or peptides known as bacteriocins (Ross et al, 2002). Their mode of action involves cell wall synthesis inhibition or depolarizes the cell membrane (Abee et al., 1995).ANTIBIOTIC ACTIVITIES Hydrogen peroxide and bacteriocins produced during fermentation are inhibitory for other bacterial growth (Oyewole, 1997). Some compounds produced after acid fermentation has antitumor properties (Hirayama and Rafter, 1999). Gastrointestinal infections such as diarrhea are caused due to changes in the local flora of gastrointestinal tract by the evading pathogen. In milk products produced by fermentation the lactic acid bacteria interfere with the colonization and spreading of food borne pathogens, resulting in the prevention of the pathogen (Gandhi, 2000). Dairy products such as yogurt, butter milk and cheese have been considered to protect against breast cancer. Experimental studies have showed that lactic acid bacteria produce antitumor effect by suppressing cancer initiation. Different mechanisms by which these bacteria induce anti cancer effect includes changes in faecal enzymes that lead to colon carcinogenesis, cellular uptake of mutagenic substances and reduction of chemical mutagens and suppression of tumors by enhanced immune response (Hosono et al. 1986).ALLEVIATION OF LACTOSE INTOLERANCESome individuals are unable to digest lactose present in milk thus causing diseases such as diarrhea, pain in the abdomin and flatulence (Panesar et al. 2006). This intolerance is due to the lack or insufficient amount of enzymes beta galactosidase and beta phosphogalctosidase which convert them into monosacchride components. Fermentation convert milk lactose to lactic acid, milk having cells of L. acidophilus helps in the digestion of lactose. Lactic acid bacteria are able to convert lactose to lactic acid by utilizing the enzyme lactase.Apart from these fermented food help in stimulation of immune system, decrease in cholesterol level, give texture to food by softening it. Fermentation enhances the food quality and safety by probiotoics.CONCLUSIONFermented foods represents approximately one-third of food consumption. From yoghurt and bread to beer and wine fermentation plays its role in not only the production of these compounds but also provides functional properties to food products and ingredients. By using different microbial strains, optimum fermentation conditions and different advanced techniques many fermented products have been manufactured such as dairy (cheese, butter) vegetables (pickles, olives, and sauerkraut), meat, beverages, bread, vinegar and other organic acids. Besides these advantages fermentation technologies are sensitive, there is a risk of contamination and intoxication therefore it should be carefully controlled.ReferencesAdams M R 1990, ‘Topical aspects of fermented foods’, Trends in Food Science & Technology vol.1, pp. 141-144.Akinrele IA 1970, ‘Fermented studies on maize during preparation of traditional African starch cake food’, J. Sci. Food Agric, vol. 21, pp.619-625Ananou S, Maqueda M, Martínez-Bueno M and Valdivia E 2007, ‘Biopreservation, an ecological approach to improve the safety and shelf-life of foods’, FORMATEXCampbell-Platt G 1987,‘Fermented foods of the world - a dictionary and guide’, London, Butterworths. ISBN: 0-407-00313-4Caplice, E., Fitzgerald, G.F, 1999, ‘ Food fermentations: role of microorganisms in food production and preservation’, International Journal of Food Microbiology, vol. 50, pp.131– 149.Doores, S., 1993. In: Davidson, P.M, Branen, A.L. (Eds.), Organic Acids. Marcel Dekker, New York, pp. 95–136.Gandhi,D N 2000, ‘Fermented Dairy Products and Their Role in Controlling Food Borne Diseases’, Food Processing: Biotechnological Applications, pp. 209-220.Hirayama, K. and Rafter, J 1999, ‘The role of lactic acid bacteria in colon cancer prevention: mechanistic considerations’, Antonie van Leeuwenhoek, vol.76, pp. 391-394.Hosono, A, Kashina, T and Kada, T 1986, “Antimutagenic Properties of Lactic Acid Cultured Milk on Chemical and Faecal Mutagens,” Journal of Dairy Science, Vol. 69, No. 9, 1986, pp. 2237-2242. doi:10.3168/jds.S0022-0302 (86)80662-2Hugas M, Garriga M and Aymerich MT 2003,‘Functionalty of enterococci in meat products’, International Journal of Food Microbiology, vol. 88(2-3), pp.223-233.Katz F 2001, ‘Active cultures add function to yoghurt and other foods’, Food Technology, vol.55, pp.46-49.Matarjemi Y and Nout M J R, 1996, ‘Food Fermentation: A safety and nutritional assessment’, Bulletin of the world health organization, vol.74(6), pp.553-559McFeeters, R F 2004,‘Fermentation Microorganisms and Flavor Changes in Fermented Food’, Journal of Food Sciences, vol.69, pp.35-37.Metaxopoulos J, Mataragas M and Drosinos EH 2009, ‘Microbial interaction in cooked cured meat products under vacuum ormodified atmosphere at 4°C’, Journal of Applied Microbiology, vol. 93(3), pp. 363-373.Nout MJR 2009,‘Rich nutrition from the poorest - Cereal fermentations in Africa and Asia’ Food Microbiology, vol. 26(7), pp.685-692.Osungbaro T O, 2009, ‘Physical and Nutritive properties of Fermented cereal foods’, African Journal of Food sciences, vol. 3(2), pp.23-27.Oyewole OB 1997, ‘Lactic fermented foods in Africa and their benefits’, Food Control, vol. 8(5-6), pp.289-297.Pandey, A. 1992, ‘Recent process developments in solid-state fermentation’,Process Biochemistry, vol. 27, pp.109–117.Panesar, P S, Panesar, R S, Singh, S, Kennedy J F and. Kumar, H 2006, ‘Microbial Production, Immobilization and Applications of ?-D-Galactosidase’, Journal of Chemical Technology and Biotechnology, Vol. 81, No. 4, pp. 530-543. doi:10.1002/jctb.1453.Paredes-López O & Harry GI 1988, ‘Food biotechnology review: traditional solid-state fermentations of plant raw materials - application, nutritional significance and future prospects’ CRC Critical Reviews in Food Science and Nutrition, vol. 27, pp.159-187.Ross, R P, Morgan S and Hill C, 2002, ‘Preservation and fermentation: Past, Present and Future’, International Journal of Food Microbiology, vol.79, pp.3-16.Schieberle P 1995, ‘Quantitation of important roast-smelling odorants in popcorn by stable isotope dilution assays and model studies on flavor formation during popping’, J Agric Food Chem, vol. 43, pp.2442-8.Schnürer J and Magnusson J 2005, ‘Antifungal lactic acid bacteria as biopreservatives’, Trends in Food Science & Technology, vol. 16(1-3), pp.70-78.Steinkraus KH 1983,‘Lactic acid fermentation in the production of foods from vegetables, cereals and legumes’, Antonie van Leeuwenhoek, Vol.49, pp.337-348.Suryanarayan, S 2003, ‘Current industrial practice in solid state fermentations for secondary metabolite production: the Biocon India experience’, Biochemical Engineering Journal, vol.13, pp.189–195. ................
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