Acid-Base Chemistry Lab Essay -- Scientific Research

The purpose of this lab was to bump the pH and total acidity of grape juice and wine. A befriend purpose was to experimentally determine the pKa of a monoprotic weak acid, polyprotic weak acid, as well as, a free amino acid, alanine. Acids and bases were defined by Bronsted-Lowry in 1923, in which acids were described as substances open of donating a proton and bases are substances capable of accepting a proton (Thompson and Dinh 2009). In addition to defining acids and bases, Bronsted-Lowry further sort out acids and bases as being either laborious or weak. By definition, a strong acid or base is a substance that is in all splitd in aqueous solutions and in contrast, weak acids only partially dissociate and reach their equilibrium with their merge base (Harris 2003). Buffers are comprised of weak acids and their conjugate bases. In the food industry, buffers are commonly used to protect changes in pH of food stuffs. The two conjugate components of the buff er resist changes in pH by absorbing the addition of any hydrogen or hydroxyl ions (Christen and Smith 2000). When weak acids and their conjugate bases are at equilibrium, their dousings thunder mug be expressed in terms of the dissociation constant, Ka. For a strong acid, the Ka value is greater than 1 x 10-2M and less than 1 x 10-2M for a weak acid (Thompson and Dinh 2009). For weak acids, the relationship of hydrogen ion concentration and pH can be defined by the Henderson-Hasselbach equation (Thompson and Dinh 2009). wine-colored quality greatly depends on the quality of the grapes and the microorganisms involved in the excitement process (Husnik and others 2006). When compared to lactic acid bacteria, yeasts are better suited for growt... ... boy HS, Hong YS, Park WM, Yu MA, Lee CH. 2009. A novel approach for estimating sugar and intoxicant concentrations in wines using refractometer and hydrometer. J. nutrient Chem. 74106-111.Thompson LD, Dinh T. 2009. Acid-Base Chemistr y. FDSC 4303/5303 food chemistry laboratory manual. Lubbock, Tx. Texas Tech University, Department of Animal and Food Sciences. Ugliano M, Moio L. 2005. Changes in the concentration of yeast-derived vapourisable compounds of red wine during malolactic fermentation with four commercial starter cultures of Oenococcus oeni. J. Agric. Food Chem. 5310134-10139. Waite JG, Daeschel MA. 2007. Contribution of wine components to inactivation of food-borne pathogens. J. Food Sci. 72286-291. Wintersteen CL, Andrae LM, Engeseth NJ. 2005. accomplishment of heat treatment on antioxidant capacity and flavor volatiles of mead. J. Food Chem. 70119-126.