Food Chemistry Chapter 1 + 2 PDF

Applied chemistry Department Food Chemistry and Nutrition Fall 2024 Dr. Nizam Diab 2  Chapter 1: Overview of Food Constituents and their Role in Food Chemistry & Nutrition Dr. Nizam Diab 3 ❑...

Applied chemistry Department Food Chemistry and Nutrition Fall 2024 Dr. Nizam Diab 2  Chapter 1: Overview of Food Constituents and their Role in Food Chemistry & Nutrition Dr. Nizam Diab 3 ❑ Definition and Importance of Food Chemistry ❑ Chemistry and Nutrition of Food Constituents Water Carbohydrates Proteins Lipids Vitamins Minerals ❑ Role of Water and Water Activity in Food ❑ The Importance of Water Activity in Foods Dr. Nizam Diab 4 Introduction ▪ Most of the organized studies of nutrition have been confined to the 20th century. ▪ Although there was evidence of long-standing curiosity about nutrition. ▪ Hippocrates, the father of medicine (400 BC) considered food as one universal nutrient. ▪ Antonie Lauret Lavoisier(18th century, a French chemist) is known as father of nutrition. ▪ In Islam there are many verses of the Quran and Hadeeths in food and nutrition. ▪ Some of these fact has just been proved by the modern science and some not. Dr. Nizam Diab 5 ▪ Nutrition has played a significant role in our life, even from before our birth. ▪ Many people are concerned only with food that relives their hunger or satisfies their appetite. ▪ But in many times, these foods don't supply their bodies with all the component of good nutrition. Dr. Nizam Diab 6  Definition and Importance of Food Chemistry ❖ Food: - Foods are products derived from plants or animals. - that can be taken into the body to yield energy and nutrients for maintenance of life ,for growth and repair tissues. - Food is that nourishes the body. - Food is a prerequisite of nutrition. ❖ Diet : is the foods and beverages a person eats and drinks. Dr. Nizam Diab 7  What is a Nutrient? A nutrient is a chemical substance in food that helps maintain the body by: provide energy, structure materials, regulating agents to support growth, repair of body's tissues and may also reduce the risks of some diseases. You need over 50 nutrients, which can be divided into six groups. - Water - Carbohydrates - Lipids (Fats) - Proteins - Vitamins - Minerals Dr. Nizam Diab 8  Are Nutritional and Food chemistry the same thing Nutritional chemistry - is the science of components of food that are of benefit to the human body. Nutritional chemistry is a process of analyzing the biochemistry of your body. Understanding your unique biochemistry is the first step in solving health problems. Body chemistry indicators, such as acid/alkaline balance, metabolic rate, stage of stress, immune system function, adrenal, hormone, and thyroid activity, mental and emotional balances, are all important to consider before starting on any nutrition or supplement program. Dr. Nizam Diab 9 Food chemistry: is the study of chemical processes and interactions of all biological and non-biological components of foods. It is similar to biochemistry in its main components such as carbohydrates, lipids, and protein, but it also includes areas such as water, vitamins, minerals, enzymes, food additives, flavors, and colors. This discipline also encompasses how products change under certain food processing techniques and ways either to enhance or to prevent them from happening. The Nutritional Chemistry and Food Chemistry are similar but : food chemistry is the study of chemical processes and interactions of all biological and non-biological components of foods ; nutritional chemistry explores the biochemistry of the body in conjunction with food Dr. Nizam Diab 10  These Nutrients Have Calories Proteins Carbohydrates Fats The Calorie: the unit used to measure the energy value of food. Calories per gram: Protein 1 gram = 4 calories Carbohydrates 1 gram = 4 calories Fat 1 gram = 9 calories Dr. Nizam Diab 11  Variables which affect nutrient needs: 1. Age 2. Gender 3. Activity Level 4. Climate 5. Health 6. State of nutrition Dr. Nizam Diab 12  WATER Function Aids digestion and cell growth and maintenance Facilitates chemical reactions Lubricates joints and cells Regulates body temperature Sources Liquids Food Breakdown of energy nutrients Dr. Nizam Diab 13  Fats Function Supply energy * Carry fat-soluble vitamins Insulate the body * Protect organs Provide essential fatty acids Sources Types of Fats Saturated: dairy products, meats, lard, coconut and palm oils Unsaturated: fish, nuts, vegetable oils Cholesterol: The fat-like substance in found in body cells. This substance clogs arteries. Dr. Nizam Diab 14  Proteins Function Builds and repairs muscles and cell tissues Helps the body make important substances Regulates body processes Supplies energy Sources Complete proteins: dairy products, eggs, fish, meat and poultry. Incomplete proteins: beans, grains and nuts. Dr. Nizam Diab 15  Vitamins Vitamins are divided into two main groups. Fat-soluble vitamins dissolve in fats are stored in fatty tissues of the body Water-soluble vitamins dissolve in water are not stored in the body Dr. Nizam Diab 16  Fat-Soluble Vitamins Nutrient Functions Sources Vitamin A - Keeps skin and mucus membranes healthy Butter, dark green and yellow fruits - Prevents night blindness and vegetables, egg yolk, liver, - Promotes growth whole and fortified milk Vitamin D - Builds strong bones and teeth Egg yolk; fortified butter, margarine, and milk; the sun Vitamin E - Acts as an antioxidant to protect cell Eggs, liver, salad oils, whole grain membranes cereals Vitamin K - Helps blood clot Cauliflower, egg yolk, organ meats Dr. Nizam Diab 17  Water-Soluble Vitamins Nutrient Functions Sources B-Complex - Helps wounds heal Oranges, grapefruits, - Helps fight infection tangerines, cantaloupe, - Helps nervous tissue function healthy broccoli, citrus fruits, tomatoes and raw cabbage - Plays important role in breakdown of proteins fats and carbohydrates Vitamin C - Keeps nervous system healthy whole grain breads and cereals (ascorbic acid) - Releases energy from food - Helps promote healthy gums and tissues Dr. Nizam Diab 18 Minerals Dr. Nizam Diab 19 Nutrient Functions Sources Calcium - Builds bones and teeth Milk, yogurt, cheese, salmon, - Helps muscles and nerves work dark veggies Iron - Combines with protein to make hemoglobin. Liver, spinach, raisins and - Helps cells use oxygen molasses Potassium - Helps nerves and muscles Potatoes, bananas, prune juice - Balances body water and tomato products Sodium - Helps nerves and muscle function Salt, soy sauce, processed foods and country ham Iodine - Promotes normal functioning of the thyroid gland Iodized salt and salt water fish Dr. Nizam Diab 20  Food For Thought Avoid excesses of some vitamins and minerals. To promote good nutrition and maintain good health: Eat a variety of foods from the food guide pyramid. Drink plenty of water Daily exercise Seek the advice of a physician or dietician before taking supplements Dr. Nizam Diab 21 Role of Water and Water Activity in Food - Food production and processing require large amounts of water of varying quality. - Water, like food, is a vehicle for the transmission of many agents of disease and continues to cause significant outbreaks of disease in developed and developing countries worldwide. - Water can also contaminate food. Contamination of foods during primary production can play a role in the transmission of food borne disease. Dr. Nizam Diab 22 In Food Processing and Preservation - Large volumes of water are needed to meet processing demands: Water is used for cleaning, as carrier for nutrients, as plasticizer, as well as diluent and for food production. - It has an important impact on all chemical reactions and physical state changes occurring during various food processing operations. - Water plays many critical roles within the field of food science: Solutes such as salts and sugars found in water affect the physical properties of water (bp & mp), Solutes in water affect water activity which affects many chemical reactions and the growth of microbes in food. - Water activity can be described as a ratio of the vapor pressure of water in a solution to the vapor pressure of pure water. Solutes in water lower water activity. Most bacterial growth ceases at low levels of water activity. 23 Dr. Nizam Diab - Water hardness is also a critical factor in food processing. - It also affects its pH balance which plays a critical role in food processing. For example, hard water prevents successful production of clear beverages. - Water activity in foods can be controlled by using : - various additives (e.g., salts, sugars etc.,), - satisfactory packaging materials - and by maintaining favorable storage conditions. Water activity measurements are increasingly being used in food research as well as in food quality control laboratories. Dr. Nizam Diab 24 The Importance of Water Activity in Foods (a) Growth of Microorganisms: Water activity indicates the amount of water in the total water content of the food which is available to micro- organisms. - Each species of micro-organism (bacteria, yeast and mould) has its own minimum water activity value below which growth is no longer possible. - Water activity has its most useful application in predicting the growth of bacteria, yeasts and moulds. For a food to have a useful shelf life without relying on refrigerated storage, it is necessary to control either its acidity level (pH) or the level of water activity or a suitable combination of the two. - Food can be made safe to store by lowering the water activity to a point that will not allow dangerous pathogens Dr. Nizam Diab 25 (b) Chemical stability: - Water activity control is an important factor for the chemical stability of foods. - Most food stuffs contain carbohydrates and proteins and are therefore subject to non-enzymatic browning reactions (Maillard reaction: an organic chemical reaction in which reducing sugars react with amino acids to form a complex mixture of compounds). - The Maillard reaction gets stronger at increasing water activity values and reaches its peak at water activity of 0.6 to 0.7. With further increase of water activity, this reaction gets rapidly weaker. - The spontaneous autocatalyctic breaking of the molecular chains of fats is strongly influenced by water activity. - Even at low water activity values, foods with a fat content acquire a rancid )‫ (زنخ‬taste after being stored for some time. 26 Dr. Nizam Diab (c) Enzymatic stability: - Most enzymatic reactions are slowed down at water activity values below 0.8. However, as many food stuffs are thermally treated during their processing, enzymatic spoilage is usually of very little importance. Dr. Nizam Diab 27 The Challenges and the role of Food Chemistry - To make foods healthier and at the same time that they still taste great. - Increased knowledge on the chemistry of constituents of foods and the changes that occur and the interactions among theses constituent gives an opportunity for controlling the processes so that better quality products with longer shelf life can be manufactured. - Food chemistry will help to design and develop new food products for the present-day consumers. - The study of the components of various food substances could be used to initiate an array of chemical reactions that could lead to the formation of either new or improved food products (taste enhancement, new aroma, color, or increased shelf life). Dr. Nizam Diab 28 Chapter 2: Major Food Constituents – Properties and Interactions Dr. Nizam Diab 29 - Nutrition is essential for the maintenance of good health of any individual. - Good nutrition can be achieved by taking a balanced diet. - Diet is a combination of different kinds of foods. No single food can give each and every nutrient required for the growth and the maintenance of the health. - Materials present in the food can be classified into six groups of compounds. (a) carbohydrates (b) proteins (c) fats (d) vitamins (e) minerals and (f) water. Dr. Nizam Diab 30  Nutrients divided into two categories: Macronutrients Are the nutrients which the body needed in large amount: carbohydrate, protein and fats. Carbohydrates, protein and fats are the main source of energy for human body. These three important major food constituents are also involved in a number of chemical reactions during different types of food processing methods. Micronutrients Are nutrients needed in lesser amounts Nizam Diab such as: Vitamins & minerals. 31 2.1 Carbohydrates 2.1.1 Monosaccharides and their Chemical Properties 2.1.2 Oligosaccharides 2.1.3 Polysaccharides 2.1.4 Properties and Functions of Starch 2.1.5 Modified Starches and their Application in the Food Industry 2.1.6 Resistant Starch 2.1.7 Selection of an Optimum Starch for Snack Development Nizam Diab 32 2.1 Carbohydrates - Carbohydrates are the most widely distributed and abundant organic compounds on earth. - Carbohydrates represent one of the basic nutrients and are quantitatively the most important source of energy. - Carbohydrates play important roles such as sweetening agents, gel or paste forming agents, thickening agents, stabilizers etc. in processed foods. - They are also precursors for aroma and coloring substances, especially on thermal processing of foods. Even the non-digestible carbohydrates play an important role in daily diet by acting as bulk material. Nizam Diab 33 - Carbohydrates: are organic compounds composed of carbon, hydrogen, and oxygen atoms (hydrates of carbon): Composed of water and carbon Cn(H2O)n Major function: They serve as a primary source of energy for living organisms. Importance of Carbohydrates: Carbohydrates play a crucial role in providing energy for cellular functions, supporting metabolism, and forming structural components in cells. Nizam Diab 34 - Carbohydrates are commonly classified into: * Monosaccharides: are polyhydroxy aldehydes or ketones, generally with a unbranched carbon chain. ( glucose, fructose, mannose and galactose). * Oligosaccharides: which are obtained from