Transcript yeasts
Yeast and its Food Application Syeda Fatma H. Bukhari Yeast Eukaryotic (mostly unicellular) Classified1.under the kingdomand Fungi. vigorous Predictable They are capable of obtaining their required energy in fermentation capabilities 2. Tolerance towards aerobic conditions (respiration) as well as high anaerobic alcohol and sulfur dioxide conditions (fermentation). levels “Yeast” as a word comes from Old English (gist or gyst) and 3. Capability of thriving between from the Indo-European root yes-, meaning foam, bubble or pH 2.8 and 4 (normal wine pH) boil. Saccharomyces cerevisiae is the most common yeast species used in processes like brewing and baking. Types of Yeast Brewer's yeast Torula Nutritional yeast Baker's yeast Types of Baker’s Yeast Cream yeast • Suspension of yeast cells in a liquid • Closest forms to the yeast slurries of the 19th century • Used in industrial bakeries Compressed yeast • Cream yeast with most of its liquid removed • Available in the form of “cake yeast” • Low shelf life Active dry yeast • Commonly available • Coarse oblong granules of yeast • Rehydrated before use • Long shelf life • More sensitive towards thermal shock during cooking Instant Yeast Rapid Rise Yeast • Higher percentages of live yeast cells per unit volume and the granules are also smaller • Shelf life is shorter than active dry yeast • Ascorbic acid • Does not require rehydration • Variety of dried yeast • Smaller granules which aid the yeast to dissolve faster in the dough • Provide a greater carbon dioxide output which allows faster rising • Bread making machines 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 from whey, molasses, blackstrap or wood pulp Uses of Yeast Extracts Yeast extract is the name given to various processed yeast products obtained by extracting the cell contents (or through removal of cell walls). They are used as food additives and flavorings, often to create savory flavors and umami taste sensations. Yeast extracts are found in a large variety of packaged food including frozen meals, junk food, crackers, gravy, stock and more. Liquid form of yeast extracts can be dried to produce a light paste or powder. Glutamic acid is one of the most widely used yeast extracts and is produced from an acid-base fermentation cycle. Methods to obtain yeast extract 1. Autolyzed yeast extract Consists of a concentration of yeast cells that are made to die and break up. This is followed by the breakdown of yeast’s proteins into simpler compounds by the action of the yeast’s own endogenous digestive enzymes. The general method of making Autolyzed yeast extract on a commercial scale is the addition of sodium chloride to a yeast suspension. The hypertonic nature of the suspension leads to the shriveling up of yeast cells, which triggers autolysis (self destruction) of yeast. The dying yeast cells are then heated to complete their breakdown, after which the husk containing the yeast with thick cell walls is separated. This removal of cell walls changes the texture and concentrates the flavor. 2. Hydrolyzed yeast extract Differs from autolyzed yeast extract in the use of enzymes that digest the yeast proteins. Hydrolyzed yeast extract is produced by the digestion of yeast proteins by exogenous enzymes or acids. YEASTS: NUTRACEUTICALS & SUPPLEMENTS BY: FARIA KHAN COMMONLY USED YEASTS: BREWER'S YEAST (SACCHAROMYCES CEREVISIAE) RED YEAST RICE (MONASCUS PURPUREUS) SACCHAROMYCES BOULARDII NUTRACEUTICALS: OSTEOARTHRITIS ANTI CANCER ANTI OXIDANT BLOOD PRESSURE IMMUNE RESPONSE MOOD CONTROL AIDS DIGESTION HEART DISEASES WHY WE NEED THEM? portmanteau of the words “nutrition” and “pharmaceutical” •Food • Food products provides health and medical benefits prevention and treatment of disease BETA GLUCAN----- A SUPER FOOD •anti cancer •immuno modulator •conquering infections •cholestrol lowering “Beta glucan is a scientifically proven biological defense modifier (BDM) that nutritionally potentiates and modulates the immune response.” It is found in the cell walls of yeast and first identified in the 1960’s by Nicholas DiLuzio, Ph.D. The cell walls of Saccharomyces cerevisiae yeast are an important source of this polysaccharide. Beta-D-Glucan “has bioactive and medicinal properties, which include immune stimulation, anti-inflammatory, anti-microbial, anti-infective, antiviral, anti-tumoral, cholesterol lowering, radioprotective and wound healing.” “the 1,3-beta-D-glucans lentinan and schizophyllan have been used clinically as adjuncts in cancer therapy.” Freimund S, Sauter M, et al, A New Non-Degrading Isolation Process for 1,3-�-D-glucan of High Purity From Baker's Yeast Saccharomyces cerevisia, Carbohydr Polymers, 2003;54:159-171. PROS AND CONS OF USING YEAST IN FOOD PRODUCTS (Saima Siddique) UG-3 INTRODUCTION CANDIDA ALBICANS HEALTH BENEFITS OF YEAST IN FOOD NUTRITIONAL YEAST (18 amino acids) (15 minerals) Valuable and well known food supplement and healthy impact on the body The essential minerals and vitamins provided by nutritional yeast include: Managing stress level Vitamin B complex (Brewer’s yeast) Biotin, pantothenic acid, riboflavin, pyridoxine, thiamine, niacin and folic acid Prevents pancreatic cancer Break down carbohydrates ,fats and proteins Healthy functioning of digestive and nervous system Important for strong and healthy hair Contributes to nail and growth and strength. Chromium (GTF) Dealing with diabetes and low blood pressure. Be helpful in reducing the amount of fat Knock down free radicals in body Selenium Improves the elasticity of skin Development of nervous system in a growing fetus Folic Acid and Fibre Rich source of fibre Excellent alternate for dairy products Plays important role in regulating blood sugar Beneficial for people having digestive issues and atherosclerosis Beneficial for vegetarian and people on low cholesterol diet Cures conditions like eczema and dermatitis NUTRITIONAL YEAST BREWER’S YEAST Deplete vitamin B in the body Stomach discomfort, excess gas and bloating Increase the effects of diabetes medications Irritable bowel disease Itching, Urticaria, and Quincke's edema Allergic reactions Tyraminehypertensiv e crisis