AMAN KUMAR M.Sc. Food Science And Technology Adm. No.: H-2019-28-M INTRODUCTION: Vegetables are generally altered by microbial flora. This flora can be inhibited under some conditions, e.g. acidity, the presence of alcohol or antibiotics in the medium, or a lack of assimilable carbon-based substrates. These conditions are created through the multiplication of certain commensal micro-organisms which grow on the plant substrate. Vegetables, which have a low sugar content and neutral pH, provide a natural medium for microbial development. Lactic acid was empirically found to stabilize such flora, and has been used for this purpose since ancient times. Starter cultures are now used to initiate fermentation, thus enhancing the control of fermented vegetable quality. LACTIC ACID FERMENTED VEGETABLES: There is a wide range of different microbial organisms in vegetables. Lactic acid bacteria are outnumbered by spoilage bacteria (Pseudomonas, Bacillus, entrobacteria), yeasts and molds. The composition of vegetables is not favourable for spontaneous growth of Lactic acid bacteria. Salting is also used in vegetable fermentation processes. A high NaCl promotes the development of lactic flora and inhibits the pectinolytic and proteolytic enzyme activities that occur, thus controlling softening and preventing putrefaction. Fermented vegetables represent an essential element of people’s diets worldwide. Sauerkraut, olives and cucumbers are often fermented, while other vegetables are sterile or frozen. In many developing countries fermented vegetables are staple foods. Lactic acid fermentation is possible on a small scale, doesn’t require additives and is inexpensive. This process usually enhances the organoleptic and nutritional quality of the final food products, which are highly appreciated by consumers. List of vegetables that can go lactic acid fermentation: Many types of brassicaceous vegetables, such as cabbage, cauliflower, broccolis, mustard vegetables. Some root vegetables, such as carrots, turnips, beet roots, radishes, celeriac. Some vegetable-fruits, such as cucumbers, olives, tomatoes, peppers, okra, green peas and green beans. Bulbs, such as onion and garlic. Some vegetable juices, such as carrots, beetroot, pepper, tomato pulp, horseradish, onion or beetroot puree, mushrooms for sauce. Many ingredients apart from salt can be used in preparation of lactic acid fermented vegetables. They may have three main functions: 1. They are a source of nutrients ,such as sugars , mineral salts and vitamins , for micro organisms that cause fermentation: 2. They help restrict the growth of unwanted bacteria, either through a regulatory effect on Ph or by producing inhibitory agents: 3. Spices can have a final flavour determining role in fermented vegetables. Country: Germany Major Ingredients: Cabbage, Salt Usage: Salad, Side Dish Product Description: Fermented shredded cabbage. The product has a sour taste with a clean acid flavour. Microorganisms: L. mesenteroides, Lactobacillus brevis, Pediococcus cerevisiae and Lb. plantarum, Starter Culture: Natural Microflora, commercial starter cultures are available. Sometimes backslopping. Salting:- The level of salting is critical to obtaining a satisfactory product, it must be within the range 2–3% w/w and is normally about 2.25%. Too little salt (<2%) and the product softens unacceptably, too much salt (>3%) and the correct microbial sequence is not obtained. The salt serves a number of purposes: (i) it extracts moisture from the shredded cabbage by osmosis to form the brine in which the fermentation will take place. (ii) it helps to inhibit some of the natural microflora of the cabbage such as pseudomonads which would otherwise cause spoilage and helps to select for the lactic acid bacteria; (iii) it helps maintain the crisp texture of the cabbage by withdrawing water and inhibiting endogenous pectolytic enzymes which cause the product to soften; (iv) finally, salt contributes to the flavour of the product Fermentation:The starter for sauerkraut production is usually the normal mixed flora of cabbage. The raw material has a large number of undesirable organisms and a small population of lactic acid bacteria (<1%) Among the lactic acid bacteria, most are Lactococcus spp. and Leuconostoc spp., and a small fraction is Lactobacillus spp. and Pediococcus spp. During fermentation, sequential growth of these lactic acid bacteria occurs. The presence of 2.25% salt, large amounts of fermentable sugars (sucrose, hexoses, pentoses), an absence of oxygen, and a low fermentation temperature facilitate Leuconostoc spp., primarily Leu. mesenteroides, to grow rapidly When the acidity has reached approximately 1% (as lactic acid), growth of Leu. mesenteroides slows down. Then Lab. brevis starts growing rapidly until acid production reaches approximately 1.5%. Then Ped. pentosaceus takes over and increases the acidity to approximately 1.8%. Finally, Lab. plantarum starts growing and brings the acid level to approximately 2%. Region: Korea Major Ingredients: Chinese Cabbage, Asian Radish, Red Pepper, Ginger, Garlic, Salt Usage: Salad, Side Dish Product Description: Fermented shredded cabbage. The product has a sour taste with a clean acid flavour. Microorganisms: L. mesenteroides, Lactobacillus brevis, Pediococcus cerevisiae and Lb. plantarum, Starter Culture: Natural Microflora, commercial starter cultures are available. Biochemistry and fermentation aspects of Kimchi are similar to sauerkraut. The best taste is claimed after 3 days at 20C when the acidity is 0.6% and the pH around 4.2. Leuconostoc mesenteroides is the principal organism responsible for the fermentation Dominance of Lactobacillus plantarum is regarded as a defect which results in an excessively sour product. Region: Mediterranean Major Ingredients: Olives, Brine Usage: Salad, Side Dish Microorganisms: L.mesenteroides, Lactobacillus brevis, Pediococcus cerevisiae and Lb. plantarum, Starter Culture: Natural Microflora, commercial starter cultures are available. Fermentation:- The initial pH of the fermentation can be above 7 depending on how much washing was done after the NaOH treatment. As a consequence, the initial microflora during fermentation can include a variety of gram-positive bacilli (Bacillus species) and gram-negative enteric bacteria (Enterobacter, Citrobacter, Klebsiella, and Escherichia). As organic acids accumulate and the pH decreases below 6, the LAB, principally Lb. plantarum, dominate the fermentation to the exclusion of the other gram-positive and gram-negative microbes. Yeast species may also be present (Candida, Pichia, Saccharomyces, and others) and contribute desirable flavor characteristics to the brined olives. Region: North America, Germany Major Ingredients: Cucumber, Spices, Dill etc Usage: Salad, Side Dish Microorganisms: Lactobacillus brevis, Pediococcus cerevisiae and Lb. plantarum, Starter Culture: Natural Microflora, commercial starter cultures are available. Sometimes backslopping. INTRODUCTION: Meat is the flesh (muscle tissue ) of warm-blooded animals, but fermented specialties from poultry ( sausages as well as cured and smoked fermented poultry) are available. What is fermented sausage? A sausage is fermented if -its pH below 5.6 and D-lactic acid content above 0.2% -its colour is heat-stable -its texture is no longer crumble -its aroma is typical -lactic acid bacteria predominate -Enterobacteriaceae counts are low a) Nutritional Role of Meat in the Human Diet: Essential component of the human diet to ensure optimal growth and development. As a concentrated source of a wide range of nutrients. High digestibility required relatively smaller guts. Meat and meat products has increased with the affluence of the consumer. Fat content of meat as consumed is around 2to5%. Protein of high biological value. Micronutrient such as iron, zinc, vitamin B1, niacin equivalents, and vitamin B12 significantly contribute to the nutritional value of meat. Red meat contains 50-60% of iron in the hame from (from hemoglobin and myoglobin). Meat is extremely susceptible to microbial spoilage. Meat as a substrate are optimal for the growth of bacteria. Water activity and pH are 0.96 to 0.97 and 5.6 to 5.8, respectively Nutrients and growth factors are abundantly available. Storage and preservation of meat is necessary for the suppression of microbial growth or the elimination of microorganisms and prevention of recontamination. The traditional methods which comprise reduction 1) Water activity ( drying, salting) and/ or pH (fermentation, acidification) 2) Smoking, storage at refrigeration or freezing temperatures, 3) Use of curing aids (nitrite and nitrate) Meat may also contain bacterial food pathogens. Meat has to be of high quality with regard to hygiene and microbial counts. Fermentation process : Two types:Foods from a comminuted matrix. Whole meat products. a) Variables in sausage production The particle size of the comminuted meat and fatty tissue (1 and 30 mm). The selection of additives (curing salt, nitrate, ascorbic acid, sodium glutamate and glucono-∂lactone -source glucose. The temperature /humidity (below 2to 3℃, the temperature is raised usually to ＞20℃ and ＞28℃, but maximum higher temperatures (32 to 38℃). The diameter of the sausages The nature of the casings smoking Heating after fermentation Supporting the development of mold growth on the surface or establishing a special tight surface film (e. g. coating with a titanium dioxide film) Dipping in antifungal preparation(sorbic acid or pimaricin) pH-4.8 to 5.4 b) Sausages as Possible Probiotics : Contain the probiotic bacterial strain which effective in the intestines. Probiotic bacteria supports survival and metabolic activity in the intestinal tract. Probiotic food should have been performed to substantiate any health claim. Lactobacilli and bifidobacteria (probiotic strains) had been used for sausage production. Lactobacillus paracasei are used for the production of moist type of fermented sausage. Large reduction of pH-∠5.0. Extended ripening―＞1 month. Drying, or excessive heating. In these condition all strains of bacteria damaged or killed.. Curing by salting (with or without the use of nitrite and/or nitrate). To achieve a water activity of ∠0.96 (equivalent to 4.5% sodium chloride). Temperatures (50C)―the salt will diffuse to the deepest part of meat. Overcoming the food poisoning through Clostridium botulinum contamination. After equilibrating the salt concentration and flavor development, the temperature is raised to 15 to 250C to ripen the ham. Optimum flavor has no changed at least 6 to 9 months, maximum 18th month. At the end of ripening step, the moisture has been reduced by 25% and salt 4.5 to 6%). Growth of LAB and concomitant acidification of the product. Reduction of nitrates to nitrites and formation of nitrosomyoglobin. Solubilization and gelification of miofibrillar and sarcoplasmic proteins. Degradation of proteins and lipids. Dehydration. a) Fermentation Microflora Sausage minces favor the growth of Micrococcacea and Lactobacilli (5×108 to 109 CFU/g). Micrococcacea such as Kocuria varians, Staphylococcus carnosus or S. xylosus grow to cell counts 106 to 107 CFU/g, when nitrate cure is applied. Inhibited the growth of organism. The predominant microorganism is isolated. Growth of Staphylococcus occurs. Penicillium constituted 96% of the microflora. The nontoxigenic species Penicillium nalgiovense was most frequently isolated. The halotolerant yeast (Debaryomyces hansenii) is the predominant. b) Acidification, Dehydration, and Microbial Antagonism Isoelectric point of meat proteins (pH 5.3 to 5.4) Increase the ionic strength. Sodium chloride and lactate in fermented sausages develop taste of the product. Acidification and drying are importance for inhibition of the growth of pathogens. Low pH and water activity exert an inhibitory effect towards pathogens. Lactic and acetic acids are the major fermentation products. The dry matter content 50-75%. The water activity values 0.86-0.92 depend on ripening. c) Proteolytic and Lipolytic Degradation during fermentation Peptides and amino acids accumulate to levels of about 1% dry matter. Peptides and amino acids act as flavor enhancers and synergists. Excess proteolysis may result in bitter and metabolic off-flavor. Amino acids and peptides are utilized by microorganisms for the conversion to flavor volatiles. The bioactive peptides is influenced by lactic fermentation. Kocuria varians is inhibited by environmental conditions Lb. casei utilizes peptides released from pork muscles Fat content 40-60% of dry matter. Long chain fatty acids are released from triglycerides and phospholipids. Free fatty acids are found 5% of the total fatty acids. Polyunsaturated fatty acids is higher than saturated d) Generation of Flavor volatiles By lipolysis and hydrolysis of phospholipids, followed by oxidation of free fatty acids. Microorganisms produce organic acids: convert amino acids and peptides to flavor-active alcohols, aldehydes, and acids. Modify products of lipid oxidation. Aroma is determined by the addition of spices, smoking, or surface-ripening with yeasts or molds. e) Biogenic amines Histamine, tyramine, phenylethylamine, tryptamine, putrescine and cadaverine not exceeding 100mg/kg. Are mainly derived from bacterial decarboxylation of amino acids. Putrescine and cadaverine are produced by the Gram-negative spoilage flora. Starter cultures inhibit rapidly metabolism of Gram negative bacteria. Effectively reduce tyramine levels in fermented sausages TRADITIONAL SPECIALITY SAUSAGES:_ DRY SALAMI:- Dry salami is made by Beef Chunk and Lean pork. GENOA SALAMI:- It is made by Lean Pork and Black Fat. ITALIAN STYLE- PEPPERONI:- It is made by Lean Pork, Regular Pork and Beef Chunks. MORTADELLA(DRY PROCESS):- It is made by Lean Pork, Lean Beef, Treated Beef Tripe, Beef/Pork Heart, Black Fat. SPANISH OR PORTUGESE SAUSAGE:- It is made by Meat, Certified Extra lean pork, Certified Belly trimmings. CERVELAT SUMMER SAUSAGE:It is made by Lean Pork Trimmings, Pork Heart, Beef Heart and Black Fat. THURINGER-STYLE SAUSAGE:It is made by Boneless Chunk, Regular Pork Trimmings, Non-Fat Dry Milk. Potential beneficial health effects of bacteria involved in meat fermentation LAB act as a human intestinal microflora and man-made ecosystems. Microorganisms may contribute to the microbial ecosystem of the gastrointestinal tract. Bacteria survive gastrointestinal transit. LAB have been predicted with the use of in vitro experiments. Some bacteria have capability to survive low pH (1.5-2.5) and bile (10mM ). To attach to enterocyte-like CaCO-2 cells. Conclusions: LAB as a part of traditional human diet or probiotic therapy. Influence the homeostasis between the intestinal microflora and the host. Prevention and treatment of certain disease. Use as a multitude of bacterial species in various food matrices. To select bacterial strains that are capable of producing a fermented meat product. Provide beneficial probiotic effects.
