Practical 3 Carbohydrates qualitative 2016 (original) (raw)
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Isolation and Characterization of Carbohydrates
Starch from potato and glycogen from chicken liver were isolated for the general test for polysaccharides, which are the molisch's test and the iodine reaction test, hydrolysis of polysaccharides (acidic and enzymatic) and for the tests such as Benedict's, Barfoed's, Seliwanoff's, and Bial's Orcinol Tests. Quantitative analysis was performed with glucose solution employing absorption spectrometry which determined the concentration of the given unknown sample using the equation of the line obtained from the graph. The absorbance of the unknown solution was 0.620 resulting to the quantifying its concentration which was 0.000896 M.
Starch and Glycogen Analyses: Methods and Techniques
Biomolecules
For complex carbohydrates, such as glycogen and starch, various analytical methods and techniques exist allowing the detailed characterization of these storage carbohydrates. In this article, we give a brief overview of the most frequently used methods, techniques, and results. Furthermore, we give insights in the isolation, purification, and fragmentation of both starch and glycogen. An overview of the different structural levels of the glucans is given and the corresponding analytical techniques are discussed. Moreover, future perspectives of the analytical needs and the challenges of the currently developing scientific questions are included.
2020
For complex carbohydrates, such as glycogen and starch, various analytical methods and techniques exist allowing the detailed characterization of these storage carbohydrates. In this article, we give a brief overview of the most frequently used methods, techniques, and results. Furthermore, we give insights in the isolation, purification, and fragmentation of both starch and glycogen. An overview of the different structural levels of the glucans is given and the corresponding analytical techniques are discussed. Moreover, future perspectives of the analytical needs and the challenges of the currently developing scientific questions are included
Activity No. 2 Qualitative Analysis of Carbohydrates
This experiment aims to introduce you with the identification of unknown carbohydrates. The test samples were 1% Dextrin, 1% Galactose, 1% Glucose, 1% Lactose, 1% Sucrose, 1% Maltose and 1% Starch. The test solutions in the Molisch test were treated with Molisch reagent and concentrated sulfuric acid. In the Orcinol test, test solutions were added with Bial’s reagent and was heated in a flame. For the Seliwanoff’s test, the test solutions were added with Seliwanoff’s reagent and was heated in a water bath. And for the Barfoed’s and Benedict’s tests, the test solutions were added with the reagent. Heated in water bath. In Barfoed’s test, the time was recorded when precipitate forms. Thus, the postive result for Molisch test is purple liquid layer. In the Orcinol’s test the positive result for pentoses is blue or green color and hexoses is yellow or brown color. For Seliwanoff’s test, the postive result is red product. Lastly, for Barfoed’s and Benedicts test were the presence of brick red precipitate.
STARCH IN FOOD. STRUCTURE, FUNCTION and APPLICATIONS
Journal of Texture Studies, 2005
This comprehensive review on starch chemistry and technology applied to food is divided into four parts and 21 chapters. The first part of the book covers starch analysis and modification. In Chapter 1, J. Preiss reviews starch synthesis in plants. The author describes a pathway of starch synthesis suggesting specific functions for starch synthesis and branching enzymes. The paper points to the possibility of producing modified starches through molecular biology techniques. Chapter 2 deals with the analysis of starch structure. E. Bertoft reviews analyses of starch structure focusing on amylopectin as the main substrate, and using enzymic methods. The author stresses the need for improved technology for routine starch component characterization. In Chapter 3, A. Blennow reviews progress in starch bioengineering, emphasizing cross disciplinary approach for starch modification. Bleenow points to the huge potential that biotechnology offers in producing starch with customized functionalities, at low cost and in an environment-friendly way. In Chapter 4, D.P. Butler et al. deal with starch-acting enzymes. The chapter reviews starch-hydrolyzing enzymes and their use for functional changes in starch and starch-based foods. The paper also describes molecular biological strategies used to obtain enzymes with new applications in starch modification. A.M. Donald in Chapter 5 reviews starch structure and functionality, highlighting the role current technology can play in understanding and modifying the structure of starch granule. The chapter by M. Peris-Totajarda in Chapter 6 is about measuring starch in food. Perris-Totajarda reviews regulations pertaining to starch analyses and describes classical and modern methods of analyzing starch in food. The second part of the book deals with the various sources of starch. H. Cornell in Chapter 7, provides a comprehensive review on the functionality of wheat starch. Wheat starch manufacturing, structure and functionality are described. Rheological properties of wheat starch paste and gels are covered, as well as wheat starch modification for application in food industry. In Chapter 8, W. Bergthaller offers a succinct review of developments in potato starch, stressing its unique functional properties. The paper covers rheological properties of potato starch, production techniques and ways to improve potato starch for food applications. The reviews ends with a brief look at future trends, especially in breeding, genetic engineering, organic potato starch and the potential offered by small potato starch granules.