Spectrophotometric Determination of Reducing and Non- reducing Sugar in Commercial Sugar Samples Mona Abdalgaum Alnour Ahmed B.Sc. (Hons.) in Chemistry, University of Khartoum (2010) A Dissertation Submitted to the University of Gezira in Partial Fulfillment of the Requirements for the Award of the Degree of Master of Science in Chemistry Department of Applied Chemistry and Chemical Technology Faculty of Engineering and Technology November, 2013 1 Spectrophotometric Determination of Reducing and Non- reducing Sugar in Commercial Sugar Samples Mona Abdalgaum Alnour Ahmed Supervision Committee : Name Position Signature Prof. Alnaeim Abdalla Ali Main Supervisor Dr. Mohammed Osamn Babiker Ahmed Co-supervisor Date: November 2013 2 Spectrophotometric Determination of Reducing and Non- reducing Sugar in Commercial Sugar Samples Mona Abdalgaum Alnour Ahmed Examination Committee: Name position Signature Prof. Alnaeim ABdalla Mohamed Chair Person Dr. Shama Elamin Daw Elbeit External Examiner Dr. Mustafa Ohag Mohamed Internal Examiner Date of Examination: 24 / 11 /2013 3 Dedication To my Family My father Mother and sister Brothers and all my friends 4 Acknowledgment I send my heart full thanks to all those who contributed to the completion of this research especial thanks to my supervisor prof. Alnaeim Abdalla for his great help in all steps of this research. Also I want to thank the Biochemistry lab staff in Agricultural researcher corporation ,. My thanks also extends to the faculty of Engineering & Technology university of Gezira for offering me the chance to pursue post graduate studies. Eventually my thanks to my friend Sara Mustafa for her help 5 Spectrophotometric Determination of Reducing and Non-Reducing Sugar in Commercial Sugar Samples Mona Abdalgaum Alnour Ahmed Master of Science in Chemistry 2014 Department of Applied Chemistry and Technology Faculty of Engineering and Technology University of Gezira Abstract Sucrose or table sugar is a non-reducing disaccharide containing the monosaccharides glucose and fructose linked by carbon atom 1 of glucose containing the aldhydic group and carbon atom 2 of fructose containing the ketonic group. The sucrose content of commercial sugar must not be less than 99.5% while the reducing sugar content must not be more than 0.1%. the aim of this work is the determination of the reducing sugars and non-reducing sugar in commercial sugar spectrophotometrically using the modified Nelson method in which the Cu+2 in alkaline solution was reduced quantitatively by glucose (reducing agent) to Cu+1 which reduced the Mo+6 in ammonium molybdate to Mo+5 to give a blue color. The spectrophotometer was used to determine the absorbance at 600 nm and from which the % of sugars was calculated. Four commercial sugar samples were collected from Wad Medani local market, two samples from Kenana and Gunied and the other two were imported from Brazil and India. The results indicated that the four samples contain 0.1 -0.23% reducing sugar and 99.27-99.9% sucrose in conformity with standard specifications of table sugar. The Gunied sample contains slightly higher percentage of reducing sugar compared to the other samples. The method is simple and easy to run and hence it is very suitable for determination of soluble sugars in commercial sugar samples and it is recommended that other sugar brands should be analyzed in the same way. 6 التحديد الطيفي للسكريات المختزلة وغير مختزلة في عينات السكر التجاري منى عبد القيوم النور أحمد ماجستير الكيمياء التطبيقية 4102م قسم الكيمياء التطبيقية وتكنولوجيا الكيمياء كلية الهندسة والتكنولوجيا جامعة الجزيرة ملخص الدراسة 7 List of Contents: page Dedication III Acknowledgment IV English Abstract V Arabic Abstract VI List of contents VII List of tables IX List of figures X Chapter one 1-1 Carbohydrate compound 1 1-1-1 Carbohydrate chemical structure 2 1-1-2 Carbohydrate classification 2 1-2 Sugar 3 1-2-1 History of sugar 4 1-2-2 Chemistry of sugar 7 1-2-3 Natural polymer of sugar 7 1-2-4 Types of sugar 8 1-3 What is sucrose 11 1-3-1 Invert sugar 11 1-3-2 Hydrolysis of sucrose 12 1-3-3 Metabolism of sucrose 12 1-3-4 Physical and Chemical Properties of sucrose 13 1-3-5 Synthesis and biosynthesis of sucrose 14 1-4 Production of sugar 14 1-4-1 Sugar beet 14 1-4-2 Sugar cane 14 1-4-3 Sugar Processing 15 1-4-4 Refining between sugar beet & sugar cane 16 1-4-5 Forms and uses of sugar 16 1-5 Consumption of sugar 17 1-6 Health effect of sugar 18 1-7 Methods of analysis of carbohydrate 20 8 1-7-1 Chromatographic and Electrophoretic 20 methods 1-7-2 Chemical Methods 21 1-7-3 Physical Methods 24 The objective of the work 26 Chapter two Materials and methods 2-1 Sample collection and preparation 27 2-2 Apparatus 27 2-3 Chemicals 27 2-4 Preparation of solution 28 2-5 Procedure 30 Chapter three (Result and Discussion) Result of concentration of reducing sugar 33 Result of concentration of total soluble sugar 34 Soluble sugar in commercial sugars sample 34 Discussion 34 Conclusion 35 References 36 9 List of table No Name of table Page 2-1 Types, colour, origin of sugar sample 27 2-2 Absorbance of the reference solution 31 3-1 Concentration of reducing sugars 33 3-2 Concentration of total soluble sugars 34 3-3 Soluble sugar in commercial samples 34 List of figures No Name of figure Page 3-1 Calibration curve of standard solution of glucose 32 10 Chapter one Introduction 1-1 Carbohydrate compounds Carbohydrates are the most abundant class of organic compounds found in living organisms. They originate as products of photosynthesis, an endothermic reductive condensation of carbon dioxide requiring light energy and the pigment chlorophyll. n CO2 + n H2O + energy CnH2nOn + n O2 As noted here, the formulae of many carbohydrates can be written as carbon hydrates, Cn (H2 O)n hence their name. The carbohydrates are a major source of metabolic energy, both for plants and animals that depend on plants for food. Aside from the sugars and starches that meet this vital nutritional role, carbohydrates also serve as a structural material (cellulose), a component of the energy transport compound Adenosine Triphosphate(ATP), recognition sites on cell surfaces, and one of three essential components of Deoxyribonucleic acid (DNA) and Ribonucleic acid (RNA). (Kovac and Saksena, 2008). Carbohydrates are one of the main types of nutrients. They are the most important source of energy for your body. Your digestive system changes carbohydrates into glucose (blood sugar). Your body uses this sugar for energy for your cells, tissues and organs. It stores any extra sugar in your liver and muscles for when it is needed. Carbohydrates are called simple or complex, depending on their chemical structure. Simple carbohydrates include sugars found naturally in foods such as fruits, vegetables, milk, and milk products. They also include sugars added during food processing and refining. Complex carbohydrates include whole grain breads and cereals, starchy vegetables and legumes. Many of the complex carbohydrates are good sources of fiber. (Aldrich, et al. , 2008). 11 1-1-1 Carbohydrates –Chemical Structure: Carbohydrates consist of the elements carbon (C), hydrogen (H) and oxygen (O) with a ratio of hydrogen twice that of carbon and oxygen.Carbohydrates include sugars, starches, cellulose and many other compounds found in living organisms. In their basic form, carbohydrates are simple sugars or monosaccharaides. These simple sugars can combine with each other to form more complex carbohydrates. The combination of two simple sugars is a disaccharide. Carbohydrates consisting of two to ten simple sugars are called oligosaccharides, and those with a larger number are called polysaccharides, (Meng, et al., 2008) 1-1-2 Carbohydrate Classification: There are a variety of interrelated classification schemes. The most useful classification scheme divides the carbohydrates into groups according to the - number of individual simple sugar units. Monosaccharaides contain a single unit of sugar. Disaccharides contain two sugar units Polysaccharides contain many sugar units as in polymers (most contain glucose as the monosaccharide unit). Carbohydrates Monosaccharide’s Disaccharides Polysaccharides Glucose Sucrose Starch Galactose Maltose Glycogen Fructose Lactose Cellulose Ribose Glyceraldehyde 12 Number of Carbons: Monosaccharide’s can be further classified by the number of carbons present. Hexoses (6-carbones) are by far the most prevalent. Number of Carbons Six = Hexose Five = Pentose Three = Triose Glucose Ribose Glyceradehyde Galactose Fructose Functional Groups: Aldoses contain the aldehyde group – Monosaccharide’s in this group are glucose, galactose, ribose, and glyceraldehyde. Ketoses contain the ketone group. The major sugar in this group is fructose. Reducing: Contain a hemiacetal or hemiketal group. Sugars include glucose, galactose, fructose, maltose, lactose. Non-reducing: contain no hemiacetal groups. Sucrose and all polysaccharides in this groups. (Pigman, et al., 1972) 1-2 Sugar: Sugar is the generalized name for a class of chemically-related sweet-flavored substances, most of which are used as food. They are carbohydrates, composed of carbon, hydrogen and oxygen. There are various types of sugar derived from different sources. Simple sugars are called monosaccharaides and include glucose (also known as dextrose), fructose and galactose. The table or granulated sugar most customarily used as food is sucrose, a disaccharide (in the body, sucrose hydrolyses into fructose and glucose). Other disaccharides include maltose and lactose. Chemically-different substances may also have a sweet taste, but are not classified as sugars. Sugars are found in the tissues of most plants but are only present in sufficient concentrations for efficient extraction in sugarcane and sugar beet.( wikipedia.org/wiki/Sruga) 13 The average person consumes about 24 kilograms of sugar each year (33.1 kg in industrialized countries), equivalent to over 260 food calories per person, per day.