Lecture 2 Food Biotechnology PDF

Biotechnological Applications In Food Industry Dr. Eman Owis Lecturer Of Microbial Biotechnology – Mansoura Uni P h. D. G ö t t i n g e n U n i - G e r m a n y [email protected]  Food b...

Biotechnological Applications In Food Industry Dr. Eman Owis Lecturer Of Microbial Biotechnology – Mansoura Uni P h. D. G ö t t i n g e n U n i - G e r m a n y [email protected]  Food biotechnology Nanotechnology in Microorganisms Fermentation Genetically Modified Enzymes in food Introduction agriculture and food associated with food Biotechnology Food industry industry & Bioethics Bacteria, yeast and Applications of Definition Introduction Genetic Engineering Introduction molds nanotechnology Production of food Ethical aspects of food Branches of Factors influencing Fermenter DNA, RNA, Peotein enzymes from and agricultural biotechnology microbial activity microorganisms biotechnology Benefits of Importance of Molecular Biology Different enzymes in Types of bacteria in the food biotechnology industry fermentation techniques food industry Food biotechnology Importance of yeasts safety and regulations in foods Different techniques associated with food biotechnology  Outputs of this Lecture Microorganisms associated with food Factors influencing microbial activity Importance of microbes in the food industry Microorganism & Microbiology Microorganism Microbiology Living things which individually are too Study of microorganisms small to be seen with the naked eye. Foundation of modern biotechnology All of the following may be considered microorganisms: Among the many – bacteria specialized fields of (eubacteria, archaebacteria) microbiology – fungi (yeasts, molds) -Mycology, Bacteriology, – protozoa Immunology, Microbial Ecology, – microscopic algae Biotechnological Microbiology, – various parasitic worms Environmental Microbiology, Food Microbiology, Forensic Microbiology, Molecular Biology Microorganism & Microbiology Two main themes involved in Microbiology 1 Basic- cellular processes 2 Applied- concerning agriculture, industry, and health Themes in Microbiology and its field All living things are composed of cells Some organisms are composed of just one cell (bacteria). Other organisms (like plants, animals, and humans) are composed of trillions of cells.  Major Differences Prokaryotic Cell Eukaryotic Cell No nucleus Has a nucleus No membrane bound organelles Has membrane bound organelles 2 major types of cells Prokaryotes Eukaryotes Bacteria Plants, Fungi Animals, Humans, etc. Microorganism Too small Germ-rapidly growing cell Has habitat Live in population (not alone) Communities are either swimming freely or attached to a surface (biofilm) Interact between communities; may either be - harmful (because of waste product) - beneficial (cooperative feeding efforts-waste→nutrient)  Microbes in our lives Some are pathogenic (disease-causing) Decompose organic waste Produces through photosynthesis (e.g.Purple sulfur bacteria must fix CO2 to live) Play a role in industry (e.g. fermentation to produce ethanol and acetone) Produce fermented food (vinegar, cheese & bread) Produce products used in manufacturing (cellulase) and treatment (insulin) Naming and Classifying microorganisms Linnaeus system for scientific nomenclature Each organism has two names: 1) Genus 2) species Scientific Names Italicized or underlined. The genus is capitalized, and the specific epithet is in lowercase A Latin origin e.g. Escherichia coli (E. coli) - describes the habitat (colon/intestine) e.g. Staphylococcus aureus (S. aureus) - Clustered (staphylo), spherical (cocci) - Gold colored colonies (aureus) Bacteria  Bacteria (P)/ Bacterium (S) Archaea A prokaryotic and single- Prokayotic cell microorganism. Lack peptidoglycan Has peptidoglycan cell Live in extreme walls environments Reproduction by Binary Include fission - Methanogens Utilize organic/inorganic - Extreme halophiles chemicals, or photosynthesis to obtain - Extreme thermophiles energy  Capsule - Some species of bacteria have a third protective covering, a capsule made up of polysaccharides (complex carbohydrates). Cell Wall - Each bacterium is enclosed by a rigid cell wall composed of peptidoglycan. The wall gives the cell its shape and surrounds the cytoplasmic membrane, protecting it from the environment. Cytoplasm - The cytoplasm of bacterial cells is where the functions for cell growth, metabolism, and replication are carried out. Cytoplasmic Membrane - A layer of phospholipids and proteins, encloses the interior of the bacterium, regulating the flow of materials in and out of the cell.  Flagella - are hairlike structures that provide a means of locomotion for those bacteria that have them. Pili - small hairlike projections emerging from the outside cell surface assist in attaching to other cells and surfaces. Ribosomes - Ribosomes are microscopic "factories“ that translate the genetic code from nucleic acid to amino acids—the building blocks of proteins.  Types of Eukaryotes Protozoa Algae Unicellular eukaryote Unicellular/multicellular eukaryote Absorb or ingest organic chemicals Has cellulose cell walls May move using pseudopods, cilia or Gain energy through photosynthesis flagella Produce molecular and organic e.g. Amoeba compounds Fungi (singular: Fungus) Eukaryotes Chitin cell walls Use organic chemicals for energy Molds and mushrooms are multicellular, consist of mycelia (composed of filaments called hyphae) Yeasts are unicellular  Yeasts Yeast is a single-celled organism that feeds on sugar, producing alcohol, carbon dioxide, heat and flavor compounds in return. There are many species of yeast existing in nature but the species used in distilling is Saccharomyces cerevisiae. So, what does a yeast cell look like? a typical yeast cell: 1.Capsule. The outer part of the cell wall. 2.Cell wall. The protective layer surrounding the cell which gives the cell structure. 3.Cytoplasmic membrane. The membrane controls the molecules and compounds that come in and out of the yeast cell. 4.Bud. The new “daughter” cell, that eventually splits off from the original “mother” cell. 5- Mitochondria. The “powerhouse” of the cell where respiration occurs. 6- Nucleus. The part of the cell containing DNA. 7- Nuclear membrane. The protective layer around the nucleus controls flow of material in and out of the nucleus. 8- Vacuole. The sac inside the cell contains water and other liquids.  Microorganisms associated with food Food serves as an interacting medium between various living species because it is a source of nutrients for humans, animals, and microorganisms. This is a natural consequence of cohabitation. Microorganisms play a significant role in producing and preserving food products. They are used in fermentation products such as bread, cheese, yogurt, beer, and wine. Microorganisms also contribute to developing new flavors and provide new textures in fermented foods.  Factors influencing microbial activity The growth and activity of the microorganisms depend on the nature of the food and its composition. The factors that govern the microbial activity in a food include both intrinsic and extrinsic factors. Intrinsic factors include: Extrinsic factors: Acidity (pH) Storage conditions of the food i.e. Water activity (aw) properties of the environment in which Oxidation- reduction potential(Eh) the food is stored. Nutrient content Temperature Presence of antimicrobials Biological structures Presence and activities of other microorganisms Acidity (pH) Microorganisms are able to grow in an environment with a specific pH - Acidophilic microorganism ‫كائنات محبة للحموضة‬ - Neutrophilic microorganism ‫كائنات محبة للتعادل‬ - Alkalophilic microorganism ‫كائنات محبة للقلوية‬ Water activity (aw) Water activity is a measure of the water available for microorganisms to grow. It is a ratio of water vapour pressure of the food substance to the vapour pressure of pure water at the same temperature. No growth of any microbe below aw = 0.60 Exceptions are : Halophilic bacteria. Nutrient content: Microorganisms require a. Energy source such as carbohydrates, amino acids, proteins, organic acids and alcohol. b. Nitrogen source such as amino acids, peptides, nucleotides, urea, proteins and ammonia. c. Carbon source Oxidation- Reduction Potential (O/R or Eh) the ratio of the total oxidizing (electron accepting) power to a substance's total reducing (electron donating) power. The more oxidized substances, the higher the Eh; the more reduced substances, the lower Eh. Microorganisms that grow at: ✓ high Eh or +ve Eh (require oxygen) – Aerobes ✓ low Eh or –ve Eh (oxygen is toxic)- Anaerobes ✓ high and low Eh (+ve /-ve Eh) – Facultative anaerobes ✓relative low Eh values – Micro-aerophilic Presence of antimicrobials: Natural constituents of foods which affect microbial growth - Lysozyme e.g. Eggs - Lactoferrin e.g. Milk - Lactoperoxidase e.g. Cow’s milk - Conglutinin e.g. Cow’s milk - Essential oils e.g. Spices and vegetables - Preservatives such as benzoic acid, sorbic acid and nisin Biological structures: Natural physical barriers to foods are: ✓ Cell walls e.g. Fruits and vegetables ✓ Shells e.g. Eggs ✓ Skin e.g. Fish Extrinsic factors: Temperature Importance of Microbes in the Food Industry FERMENTED FOOD PRODUCTS Cheese Yoghurt Sauerkraut  FERMENTATION Microorganisms are the key building blocks of fermented foods & beverages The final product of fermentation is the result of chemical, physical & biological interactions between specific microbes & food Bacteria, Yeast & molds are involved in food fermentation Sugar →Alchohol + Co2  1- Fermented products Yoghurt → Streptococcus thermophilus, Lactobacillus bulgaricus. Cheese → Streptococcus sp. Lactococcus lactis. sauerkraut → Enterobacter cloacae & Erwinia herbicola CHEESE ✓ Cheese is a milk product ✓ Method of preserving milk ✓ Purely a product of microbial fermentation ✓ Flavor & aroma changes depending upon the microbes being used ✓ As a carrier for probiotics ✓ Rich in nutrients : high content in protein, calcium, riboflavin, vitamin A&D Production of cheese ✓ A starter culture is added to pasteurized milk ✓ Fermentation changes the sugar to acid causing curd ✓ Rennet (enzyme) is added to speed up the process ✓ Whey is drained off ✓ Cut the curd & scalding stirring ✓ And cheddaring – squeezing & stretching the curd ✓ Salting to prevent starter activity, flavor, and release of whey ✓ Moulding & pressing (further release of whey) ✓ Ripening ✓ Cheese produce PRODUCTION OF CHEESE Roquefort cheese Blue cheese is a fermented cheese that uses Penicillium roqueforti mold cultures. However, unlike other types of mold, these cultures are nontoxic and safe for human consumption. Blue cheese can help promote bone health, dental health, and heart health. The cheese is white, tangy, creamy, and slightly moist, with veins of blue mold. It has a characteristic fragrance and flavor with a taste of butyric acid.  A fermented dairy product whereby milk is inoculated Yogurt with bacterial culture Lactose → lactic acid → acid causes casein to denature & hold water into a semi-solid gel (yogurt) Lactococcus thermophilus & Streptococcus bulgaricus are involved in yogurt production S.thermophilus brings the pH of the milk down to 5.5 L.bulgaricus converts lactose to lactic acid Taste depends on organoleptic aspects & no. of lactic enzymes contained. Production of yogurt ✓Based on production & physical structure ✓Three methods: ❖Set yogurt: fermentation of milk is carried out in a container ❖Stirred yogurt: gel structure is broken before cooling & packaging ❖Fluid yogurt: stirred yogurt of low viscosity PRODUCTION OF YOGHURT Sauerkraut Sauerkraut is the clean, sound product of characteristic flavor, obtained by full fermentation, chiefly lactic, of properly prepared and shredded cabbage in the presence of not less than 2% and not more than 3% salt. The word has German origin, meaning “sour cabbage”. It has a sour taste with a clean acid flavor. Mild flavoured, sweet, solid, white-headed cabbage is the best choice for making superior kraut. Preparation of Sauerkraut Fermentation The juice contains natural flora from soil and some contaminants from soil and water. At first different kinds of bacteria grow but then acid- forming soon predominate. Early microbes to predominate include Enterobacter, Erwinia, which produce volatile acids and gas and contribute to some flavor. Soon, Leuconostoc bacteria begin to outgrow all other organisms and continue producing lactic acid. They attack sugars to form lactic acid, acetic acid, ethanol, mannitol, dextran, esters, and carbon dioxide, which contribute to the good flavor of sauerkraut.  2- Single cell proteins Refers to the dried cells of microorganisms such as algae, bacteria and fungi. Used as protein sources in animal feeds including human food supplements. – Eg. Pruteen - Made from the bacterium Methilophilus methilotrophus. – Spirulina – cyanobacteria of the genus Arthrospira. Whole cells as well as beta carotenes from spirulina are available.  3- Production of Beer ▪ The process of manufacturing beer is called brewing. ▪ Beer is an alcoholic beverage made by yeast fermentation of grains to ethanol and CO2. ▪ Beer is an example of a malt beverage. ▪ Brewing is a complex fermentation process because several factors that do not result from microbial activity (e.g., Flavor, aroma, clarity, foam formation, foam stability, etc.) are considered in this fermentation. Types of beer:- ▪ There are two major types of beer based on fermentation differences. ❑Bottom fermented beer ▪ are generally called lager beers and utilize bottom yeast in their manufacture. ▪ As the fermentation subsides, bottom yeast tends to flocculate and settle at the bottom. ▪ Example of bottom yeast are Saccharomyces uvarum,. Bock beer, Pilsen beer is lager beers. ❑Top fermented beer- is called ales. ▪ Production of ales utilizes top yeast, which during fermentation rises to the surface and floats on the surface of fermentation broth. ▪ Some strains of Saccharomyces cerevisiae are top yeast. 4- Yeast as a food supplement (Nutritional Yeast ) ▪ Deactivated yeast, often a strain of Saccharomyces cerevisiae ▪ Used as dietary supplements. ▪ Nutritional yeast is rich in many basic nutrients that the body requires: B vitamins (excluding B12), chromium, minerals, amino acids, and vitamins (excluding A, C, and E). ▪ Yeast also has high phosphorous content. ▪ There are two primary sources from which nutritional yeast is derived: from brewing beer and whey, molasses, blackstrap, or wood pulp Types of Backer’s Yeast  Assignment Are there additional applications of microorganisms in the food sector? Give one example