Principles Of Food Science And Processing 2024 Lecture 1 PDF

Principles of Food Science and Processing an overview 1st lecture Dr. Mohamed Elsaadany  Outline Food science Core areas in Food Science Significance of Food Science and Technology Classification of Food Food Constituents Water in food im...

Principles of Food Science and Processing an overview 1st lecture Dr. Mohamed Elsaadany  Outline Food science Core areas in Food Science Significance of Food Science and Technology Classification of Food Food Constituents Water in food importance of water Forms of water in food Specific Heat of water Dr. Mohamed Elsaadany 2 1 Food Science Dr. Mohamed Elsaadany 3  Food Science Food science is the application of the basic sciences and engineering to study the fundamental physical, chemical, biochemical nature of foods and the principals of processing.  Food is any substance that, when ingested, usually will supply nutrients that nourish the body.  Nutrients are the constituents of food i.e. Carbohydrates, Proteins, Lipids, Vitamins, Minerals and Water.  Processing involves any operation that will alter the value of food in order to enhance: shelf life, consumer acceptance and nutrient load. 4 Dr. Mohamed Elsaadany 4  Core areas in Food Science Food Science emerged as a discipline in early 1950’s. Broad discipline that holds many specializations:  Food Chemistry/Nutrition  Food Engineering/Technology  Food Microbiology  Food Processing & Packaging  Food Safety  Sensory Science  Product development  Education & Careers  Public Policy & regulation The terms Food Science and Food Technology are often used synonymously.  Food Technology is the application of food science to the selection, preservation, processing, packaging, distribution and use of safe, nutritious, and wholesome 5 food. Dr. Mohamed Elsaadany 5 Significance of Food Science and Technology Developed as world’s largest industry Transformation of food from agriculture to industrial farming Enormous impact on human health and the quality of life Food freshness retention Deterioration and spoilage prevention Supplying quality food to the distant areas and in off season Regulating food supply Consumer convenience in food cleaning, preparation, storage and Cooking time reduction Suppling clean, safe, wholesome food over the counter Nutrient enriched food products Producing special food for special cases like diabetes, heart disorders, allergies etc. 6 Dr. Mohamed Elsaadany 6 Significance of Food Science and Technology Suppling food along on journeys such as Ships Airlines and Astronauts Waste utilization & reduction in environmental pollution for example utilization of food waste (husk, peels, pits, seeds, stems, leaves) to Develop new food products Enrich nutrient content of existing food products (supplementation) Produce organic manure or fertilizers Production of Oils, fibres or pectins Production in herbal supplements or medicines Food industry emerged as the biggest industry with Enormous economic gains and profits 7 Dr. Mohamed Elsaadany 7  Food sources Primarily there are two main sources of food:  Plants Sources and Animal Sources Fishes are sometimes treated separately as a third group:  Plant Sources: Fruits, vegetables, roots, stems, leaves, flowers, seeds, nuts, legumes, pulses, herbs, spices etc.  Animal Sources: Worldwide numerous species are considered edible. For Muslims only split-hoofed ruminants and selected birds are Halal/edible. Cows, buffalo, sheep, lamb, goat, deer, camel, hen, duck, turkey, quail. 8 Dr. Mohamed Elsaadany 8  Classification of Food Classification based on Perishability Foods can be classified into three groups depending on how long they can be kept without any treatment Stable Semi-Perishable Perishable Stable Foods Remain acceptable for long period of time if stored properly Usually from 3 months to 3years Can be stored on shelf/room temperature Moisture content less than 15% Includes: honey, sugar, dry Cereals, legumes, pulses, processed foods ( powdered milk, cereals, pasta) etc. 9 Dr. Mohamed Elsaadany 9  Classification of Food Semi Perishable Foods Remain fit for consumption for a fairly long period of time when handled and stored carefully. Shelf life ranges from few weeks to few months Moisture content 60-90% Included: potatoes, onions, ginger, garlic, some varieties of apples, commercial processed foods like scacks, cheese, icecream Spoiled by autolysis and growth of microorganisms Good handling and proper storage increases shelf life. 10 Dr. Mohamed Elsaadany 10  Classification of Food Perishable Foods Very short Shelf life usually from few hours to few days Needs immediate attention like refrigeration to prolong shelf life. Moisture content 80-95% Readily spoiled by autolysis and microorganisms Include fresh commodities like fresh fruits, vegetables, milk, meat, fish, eggs, processed foods like pasteurized milk, cottage cheese, fresh cream, cakes, bakery biscuits, bread etc. Canned foods are served as perishable when opened. 11 Dr. Mohamed Elsaadany 11  Classification of Food Classification on the basis of pH In chemistry, p H is a numeric scale used to specify the acidity or basicity of an aqueous solution. The acidity of foods has been used for centuries to preserve foods. p H determine the rate of microbial survivors. It gives information on: Food spoilage organism Food poisoning microorganism Choice of heat processing temperatures 12 Dr. Mohamed Elsaadany 12  Classification of Food Classification on the basis of pH Divided into four categories: 1. High Acid 2. Acid 3. Medium acid 4. Low Acid High Acid Foods: pH below 3.7 Includes citrus fruits, fermented vegetables/pickles Spoilage organisms associated with these are yeast or moulds Boiling water can destroy these organisms Aciduric (acid resistant) bacteria can pose problems Food poisoning bacteria do not thrive in high acidic foods 13 Dr. Mohamed Elsaadany 13  Classification of Food Acid Foods: pH 4.5-3.7 Includes guava, orange, mango, pineapples, tomatoes etc. Spoilage is caused by enzymes and aciduric bacterias that are low heat resistant and can be killed by pasteurization Examples are: some mesophilic spore forming bacteria like: Clostridium Pasteurianium Bacillus thermoacidurans a spore forming bacteria cause sour spoilage even in canned juices Food poisoning organisms usually don’t grow in acid foods 14 Dr. Mohamed Elsaadany 14  Classification of Food Medium Acid Foods: pH 5-4.5 Includes most meats and vegetable mixtures Same spoilage organisms as before Low Acid Foods: pH 5 orabove Most vegetables (Okra, green leafy veg., carrots, beans), meat, milk, eggs, fish Spoiled by enzymes and mesophilic spore forming bacteria, thermophilic bacteria and non-forming organisms. Examples are: Clostridium Botulinum, Clostridium sporogenes. Destroyed at high temperature Food poisoning organisms prefer grow in medium and low acid foods. 15 Dr. Mohamed Elsaadany 15  Mode of Food Spoilage Microbial spoilage is often due to the growth and/or metabolism of spoilage bacteria, yeasts or moulds. Chemical spoilage may be via nonmicrobial enzymic action, oxidation or non-enzymic browning. Physical spoilage include water loss; increase in moisture of dry foods; freezer burn; and recrystallisation of frozen foods. Mechanical agents: Insects, pests, rodents, birds. Autolysis spoilage is caused by auto-change mechanism in living organisms that can deteriorate food constituents i.e. over ripening & browing due to oxidation, softening of fruit pectin by hydrolysis, wilting of leaves, putrefaction of animal products. 16 Dr. Mohamed Elsaadany 16  Food Constituents Types of food constituents: On the basis of their functionality 1. Energy giving: Carbohydrates, Proteins, Fats 2. Growth & Body building: Proteins, Some minerals 3. Maintenance: Vitamins, Minerals On the basis of requirement: 1. Macronutrients: Carbohydrates, Proteins, Fats, Water 2. Micronutrients: Vitamins, Minerals 17 Dr. Mohamed Elsaadany 17  Food Constituents Chemically food is composed of following constituents: 1. Carbohydrates 2. Proteins 3. Fats/Lipids 4. Vitamins 5. Minerals 6. Water 18 Dr. Mohamed Elsaadany 18 2 Water Dr. Mohamed Elsaadany 19  Water in food Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Safe drinking water is essential to humans and other life forms Water plays an important role in the world economy, as it functions as a solvent for a wide variety of chemical substances and facilitates industrial cooling and transportation. Major Function Digestion food Transport nutrient Lubricant Reregulate body temperature 20 Dr. Mohamed Elsaadany 20  Water in Foods Importance of water  Water is abundant in all living things and consequently is in almost all foods, unless steps have been taken to remove it.  It is essential for life, even though it contributes no calories to the diet.  Fruit and vegetable contain >90%, milk88%, meat 60-750%, dried food