Under supervision ofProf. Dr. Nafisa Hassan al-BannaProfessor of nutritionNutrition and Food Science Department.Faculty of Home Economic.Helwan University.Prof.Dr.Mona Samy HalabyProfessor of food sciencesNutrition and Food Science Department.Faculty of Home Economic.Helwan University.
of probioticsA century ago, ElieMetchnikoff (a Russianscientist, Nobel laureate, andprofessor at the PasteurInstitute in Paris) postulatedthat lactic acid bacteria (LAB)offered health benefitscapable of promotinglongevity..
5The German professor Alfred Nissle isolated anon-pathogenic strain of Escherichia coli fromthe feces of a First World War soldier who didnot develop enterocolitis during a severeoutbreak of shigellosis.A Bifidobacterium was first isolated by HenryTissier (of the Pasteur Institute) from a breast-fed infant, and he named the bacterium Bacillusbifidus communis.
DefinitionsProbiotics:Probiotics are live microbes thatcan be formulated into manydifferent types of products,including foods, drugs, anddietary supplements.Prebiotics :Prebiotics are dietary substances (mostlyconsisting of nonstarch polysaccharidesand oligosaccharides poorly digested byhuman enzymes) that nurture a selectedgroup of microorganisms living in the gut.
Traditional dietary sources of prebiotics includesoybeans, inulin sources (such as Jerusalemartichoke, jicama, and chicory root), raw oats, unrefinedwheat, unrefined barley and yacon.prebiotics
Unlike probiotics, most prebiotics are used as foodingredients in biscuits, cereals, chocolate, spreads, anddairy products, for example: Commonly known prebioticsare: Oligofructose.Inulin.Galacto-oligosaccharides.Lactulose.Breast milk oligosaccharides.Fermentation of oligofructose in the colon results in a largenumber of physiologic effects, including:Increasing the numbers of bifidobacteria in the colon.Increasing calcium absorption.Increasing fecal weight.Shortening gastrointestinal transit time.Possibly, lowering blood lipid levels.
The increase in colonic bifidobacteria has been assumed tobenefit human health by producing compounds to inhibitpotential pathogens, by:Reducing blood ammonia levels.Producing vitamins and digestive enzymes.Synbiotics:Synbiotics are appropriate combinations ofprebiotics and probiotics. A synbiotic product exertsboth a prebiotic and probiotic effect.
Bacteria ResponsibleLactic acid bacteria (LAB) are themost common type of microbesused. LAB has been used in thefood industry for manyyears, because they are able toconvert sugars (including lactose)and other carbohydrates intolactic acid.This not only provides the characteristic sour taste of fermenteddairy foods such as yogurt, but also by lowering the pH maycreate fewer opportunities for spoilage organisms togrow, hence creating possible health benefits on preventinggastrointestinal infections.
Desirable Probiotic PropertiesIn order for a potential probiotic strain to be able to exertits beneficial effects, it is expected to exhibit certaindesirable properties. The ones currently determined by invitro tests are:•Acid and bile tolerance which seems to be crucial fororal administration.•Adhesion to mucosal and epithelial surfaces, animportant property for successful immune modulation,competitive exclusion of pathogens, as well asprevention of pathogen adhesion and colonization.•Antimicrobial activity against pathogenic bacteria.•Bile salt hydrolase activity.
•Able to survive the passage through the digestivesystem.•Able to attach to the intestinal epithelia and colonise.•Able to maintain good viability.•Able to utilise the nutrients and substrates in a normaldiet.•Non pathogenic and non toxic.•Capable of exerting a benificial effect on the host.•Stability of desired characteristics during processing,storage and transportation.•Anti-inflammatory,antimutagenic, immunostimulatory.Characteristics of Effective Probiotics
Mechanism of ActionInhibit Potentially Pathogenic Microorganisms (PPMs) Reduction in Intestinal pH ( through production of SCFAs) Production of bacteriocins Competitive blocking of adhesion sites Competition for nutrients
Mechanisms of probiotics activity
Uses for Health PurposesFriendly bacteria are vital toproper development of theimmune system, to protectionagainst microorganisms that couldcause disease, and to thedigestion and absorption of foodand nutrients.“Unfriendly” microorganismssuch as disease-causingbacteria, yeasts, fungi, andparasites can also upset thebalance