CAN THO UNIVERSITY COLLEGE OF NATURAL SCIENCES THEMATIC REPORT ROLES OF BACTERIA IN FOOD GUIDANCE LECTURER: PhD Nguyễn Thị Phi Oanh STUDENT PERFORMANCE: Trần Chí Linh B1303493 Nguyễn Thị Hồng Lẹ B1303491 Trần Thị Ngọc Loan B1303494 Võ Thị Quyền Qúy B1303603 Võ Chí Linh B1303 Nguyễn Thành Luân B1303 THE STRUCURE OF REPORT I THE CONCEPT OF FOOD AND BACTERIA II THE EFFECTS OF BACTERIA ON FOOD III INTRODUCTION OF LACTIC ACID BACTERIA IV APPLICATION OF BACTERIA IN FOOD V CONCLUSION I CONCEPT OF FOOD AND BACTERIA Food • Food is any substance consumed nutritional support for the body to provide • Food is usually of plant or animal origin, and contains essential nutrients, such as fats, proteins, vitamins, or minerals • The substance is ingested by an organism and assimilated by the organism's cells to provide energy, maintain life, or stimulate growth I CONCEPT OF FOOD AND BACTERIA Bacteria • Bacteria were among the first life forms to appear on Earth, and are present in most of its habitats • Bacteria inhabit soil, water, acidic hot springs, radioactive waste and the deep portions of Earth's crust • Bacteria also live in symbiotic and parasitic relationships with plants and animals • They are also known to have flourished in manned spacecraft II THE EFFECTS OF BACTERIA ON FOOD Good bacteria • Some bacteria possess properties that can benefit food production or conversion • Many food-grade bacteria are used to produce a variety of fermented foods from raw animal and plant materials • The acidic, and in part organolytic, properties of fermented products result from the fermentative activities of these bacteria • Foods such as ripened cheeses, fermented sausages, sauerkraut and pickles have not only a greatly extended shelf life compared to the raw materials from which hey are derived, but also aroma and flavor characteristics contributed directly or indirectly by the fermenting organisms II THE EFFECTS OF BACTERIA IN FOOD Bad bacteria • Microbial contamination of foods can have many undesirable consequences ranging from spoilage to foodborne illness http://www.baomoi.com http://petrotimes.vn III INTRODUCTION OF LACTIC ACID BACTERIA Lactic acid bacteria • The colonies are small round, glossy – clear, opalescent or yellow of cream; or colonies are large round, outstanding, opalescent Also colonies have sour smell of acid • LAB need nitrogen from some acid amin, vitamin, growth substance, and some mineral The best carbon that they growth are small glucoses, alcohol Figure The colonies of LAB http://ryfypo.hst.im/78/ III INTRODUCTION OF LACTIC ACID BACTERIA Lactic fermentation Lactic fermentation is anerobic metabolism from sugar to lactic acid by some lactobacilli: Bacterium lactic, Bacterium delbriski, Bacterium casei,… III INTRODUCTION OF LACTIC ACID BACTERIA a Homofermentative pathway Lactic acid is main product (90 - 98% in fermentation products total), subproducts are ethanol, acid acetic, CO2 C6H12O6 2C3H6O3 (Glucose) (Lactic acid) b Heterofermentative pathway Only 50% glucose was created lactic acid Subproducts are ethanol, acid acetic, CO2 It can interact each other to create smell ester C6H12O6 2C3H6O3 + C2H4(COOH)2 + CH3COOH + C2H5OH + CO2 + H2 (Glucose) (Lactic acid) (Succinic acid) (Acetic acid) (Ethanol) III INTRODUCTION OF LACTIC ACID BACTERIA Classification of LAB According to fermentation method, Lactobacilli includes two species: Homolactic and Heterolactic bacteria a Homolactic bacteria Homolactic bacteria are lactic bacteria create main products are lactic acid in glucose fermentation process There are two genera take part in this fermentation process: Lactobacillus and Streptococcus Figure Lactobacillus bulgaricus http://bioweb.uwlax.edu III INTRODUCTION OF LACTIC ACID BACTERIA Some Lactic bacteria species in Homolactic bacteria III INTRODUCTION OF LACTIC ACID BACTERIA b Heterolactic bacteria Heterolactic bacteria are lactic bacteria create a little lactic acid in glucose fermentation process Other some subproduct are ethanol, acid acetic Like Homolactic bacteria Lactobacillus and Streptococcus have some common species: Lactobacillus brevis, Streptococcus fulcalis, and Streptococcus cumoris Figure 10 Lactobacillus brevis www.brewingscience.com enfo.agt.bme.hu IV APPLICATION OF BACTERIA IN FOOD Fish sauce • Uneviscerated fish is mixed with salt and placed in fermented tanks about six month • Streptococcus, Micrococcus and Bacillus speces are involved in this fermentation process • This product is dark couloured with a distinctaroma IV APPLICATION OF BACTERIA IN FOOD Kim Chi • Kim chi is the fermented napa cabbage • Kimchi is processed with various seasonings, such as red pepper powder, garlic, ginger, green onion, fermented seafood (jeotgal), and salts, at low temperatures • Lactic acid bacteria and included several species of the genera Lactobacillus, Leuconostoc and Weissella are involved in this fermentation process IV APPLICATION OF BACTERIA IN FOOD Soy sauce • Soy sauce is the mixtrure of soybeans, wheat, salt and water • The wheat-soy mixture is exposed to specific strains of mold called Aspergillus oryzae or Aspergillus soyae, which break down the proteins in the mash • Further fermentation occurs through addition of specific bacteria (lactobaccillus) and yeasts which enzymatically react with the protein residues to produce a number of amino acids and peptides • These protein derivatives all contribute flavor to the end product IV APPLICATION OF BACTERIA IN FOOD Yogurt • Yogurt is made by fermenting many types of milk with lactic acid bacteria • The good bacteria most commonly used as probiotics are lactic acid bacteria, such as lactobacillus bulgaricus, lactobacillus acidophilus, L animalis and L casei, the probiotic Bifidobacterium strains B animalis and B lactis, Streptococcus thermophilus • To turn milk into yogurt, these bacteria ferment the milk, turning the lactose sugars in the milk into lactic acid The lactic acid is what causes the milk, as it ferments, to thicken and taste tart V CONCLUSION • Food, bacteria and humans have an intimate relationship with each other very interesting for a long time, before both the record of history • Food not only has nutritional value for humans but also the ideal culture medium for the growth of bacteria • Fermented by bacteria that can lead to the ability to preserve food instead of food spoil • Therefore, people have long been promoted: Study rules of bacterial activity with the relevant food The study method using the friendly bacteria to food processing Research methods to control the harmful bacteria, prevention of food spoilage Research test methods bacteria in foods, identifying food safety standards V CONCLUSION • Bacteria can be used to turn raw food into your favorite food, such as cheese, pickles, yogurt, the tofu (bean curd powder), sausage, sauce, fish sauce, soy sauce, noodles, noodles, yeast cake bacteria can directly affect food quality and human health • In terms of benefits, the nutrient-rich foods are essential for humans • The growth of bacteria in food can lead to either safety or to help preserve the food spoil • This depends on the relationship between bacteria and food storage conditions • Therefore, people need to continue to improve the understanding of the bacteria to be able to exploit the benefits tubers them up REFERENCES Michael P., J Meng, 2006 Bacteria in Food and Beverage Production, Prokaryotes,1:797–811 Tran Minh Tam, 2000 Microbiological technology applications Agriculture Publisher, TP HCM Dong Thi Thanh Thu 19, 2003 Biochemical applications National University Publishing House, TP.HCM Nguyen Duc Luong, 2006 Microbiological technology National University Publishing House, TP HCM THANKS FOR WATCHING AND LISTENING [...]... INTRODUCTION OF LACTIC ACID BACTERIA Some Lactic bacteria species in Homolactic bacteria III INTRODUCTION OF LACTIC ACID BACTERIA b Heterolactic bacteria Heterolactic bacteria are lactic bacteria create a little lactic acid in glucose fermentation process Other some subproduct are ethanol, acid acetic Like Homolactic bacteria Lactobacillus and Streptococcus have some common species: Lactobacillus brevis, Streptococcus...III INTRODUCTION OF LACTIC ACID BACTERIA 3 Classification of LAB According to fermentation method, Lactobacilli includes two species: Homolactic and Heterolactic bacteria a Homolactic bacteria Homolactic bacteria are lactic bacteria create main products are lactic acid in glucose fermentation process There are two genera take part in this... with lactic acid bacteria • The good bacteria most commonly used as probiotics are lactic acid bacteria, such as lactobacillus bulgaricus, lactobacillus acidophilus, L animalis and L casei, the probiotic Bifidobacterium strains B animalis and B lactis, Streptococcus thermophilus • To turn milk into yogurt, these bacteria ferment the milk, turning the lactose sugars in the milk into lactic acid The lactic. .. Lactobacillus and Streptococcus have some common species: Lactobacillus brevis, Streptococcus fulcalis, and Streptococcus cumoris Figure 10 Lactobacillus brevis www.brewingscience.com enfo.agt.bme.hu IV APPLICATION OF BACTERIA IN FOOD 1 Fish sauce • Uneviscerated fish is mixed with salt and placed in fermented tanks about six month • Streptococcus, Micrococcus and Bacillus speces are involved in this fermentation... Kim chi is the fermented napa cabbage • Kimchi is processed with various seasonings, such as red pepper powder, garlic, ginger, green onion, fermented seafood (jeotgal), and salts, at low temperatures • Lactic acid bacteria and included several species of the genera Lactobacillus, Leuconostoc and Weissella are involved in this fermentation process IV APPLICATION OF BACTERIA IN FOOD 3 Soy sauce • Soy... medium for the growth of bacteria • Fermented by bacteria that can lead to the ability to preserve food instead of food spoil • Therefore, people have long been promoted: Study rules of bacterial activity with the relevant food The study method using the friendly bacteria to food processing Research methods to control the harmful bacteria, prevention of food spoilage Research test methods bacteria