CHE 425 TECHNOLOGY OF FOOD PRESERVATION

1. CHE 425TECHNOLOGY OF FOOD PRESERVATION

2. Class Hours: T1 (KB 428), Th1,2 (KB428), Office: M 11:00-12:30 Book: Photocopies from different sources. Grading: 2 midterms 2x30 = 60% final exam : 40% attendance bonus : 0.10 x %att.

3. WHY IS FOOD A DIFFERENT FIELD? Products of food Industry are consumed by human beings Foods are living systems

4. FACTORS OF SPECIAL IMPORTANCE (competing)! SAFETY : Since foods are living systems, biochemical and microbiological changes take place continuously. NUTRITIVE VALUE: Composition; carbohydrate, protein, fat, vitamin, mineral etc. contents. Changes in these components during processing, storage and other phases of food chain. ORGANOLEPTIC PROPERTIES: * Flavor (smell and taste) * Color * Texture (perceived mouth feel)

5. Food Industry Raw material production and acquisition ( maintenance of raw material flow at optimum level, quality control) Processing (maintenance of adequate manufacturing pace, quality assurance) Warehouse storage (proper storage conditions, quality control) Transport and distribution (maintenance of steady, timely distribution to consumer centers, quality control) Market storage and retail (quality control, shelf life)

6. Industries Supplying to Food Sector Packaging : Cans, jars, pouches, plastics, cartons, papers, wood, metal, laminates, printing houses etc. Chemical Industries: Additives such as acidulants, preser- vatives, emulsifying agents, enzymes, stabilizers, coloring materials. Fertilizers, insecticides, sanitizing agents, pesticides, various other chemical sprays. Machines, Maintenance and Repair Requirements: Farming, harvesting machinery, processing lines, distribution vehicles, spare parts, lubricants etc.

7. % contributions to the total national income of Turkey Agriculture : 20.5% Food : 16.6% Petroleum Industry : 6.0%

8. Relative expenditures (%) for various foods Meats 29.6 Dairy products 18.1 Bakery and cereal products 15.4 Processed fruits and vegetables 10.6 Fresh Vegetables 6.7 Fresh fruits 4.2 Poultry 4.0 Fats and Oils 3.6 Eggs 3.2 Other 4.6

9. Typical Curricilum in Food Engineering Food Chemistry (1 semester, 4 credits): Basic composition, structure and properties of foods and the chemistry of changes occuring during processing and utilization. Food Analysis (1 semester, 4 credits): Principles, methods and techniques of quantitative physical and chemical analyses of foods and food products, the analyses to be related to the standards and regulations pertaining to food processing and quality standards.

10. Food Microbiology (1 semester 4 credits): Relationship of habitat to the occurance of microorganisms in foods; microbial action in relation to food spoilage and food manufacture; physical, chemical and biological destruction of microorganisms in foods; methods for microbiological examination, public health and sanitation. Food Engineering (2 or 3 semesters, 8-9 credits): Engineering concepts and unit operations applicable to food processing. Principles would include mechanics, transfer and rate processes and process control instrumentation. Unit operations would include fluid flow, heat transfer, evaporation, drying, extraction,distillation, filtration, mixing and material handling.

11. Food Processing (2 semesters or 8 credits): General characteristics of food raw materials; harvesting, assembling and receiving of raw materials, methods of food preservation; processing objectives including factors influencing food acceptability and preferences; packaging; water, waste disposal and sanitation.

12. COURSE OUTLINE BIOLOGICAL, MICROBIOLOGICAL BACKGROUND INTRODUCTION ( Defining Food Science, Magnitude, Division and Interdependent Activities of the Food Industry, Food and Man) CONSTITUENTS OF FOODS, PROPERTIES AND SIGNIFICANCE (Water, Carbohydrates, Proteins, Fats, Other Constituents) ENZYMES NUTRITIVE ASPECTS OF FOOD CONSTITUENTS ( Vitamins, Minerals, Enzymes, Other) FACTORS THAT INFLUENCE MICROBIAL ACTIVITY IN FOODS (Moisture, Water Activity, Oxidation-Reduction Potential, Temperature, Acidity, Inhibitors) TEMPERATURE IN MICROBIAL ACTIVITY IN FOODS FOOD SPOILAGE

13. COURSE OUTLINE PRESERVATION PRINCIPLES AND OPERATIONS HEAT PROCESSING EVAPORATION DEHYDRATION CHILLING AND FREEZING IRRADIATION FERMENTATION AND PICKLING PRESERVATION AS SUGAR CONCENTRATES PRESERVATION WITH CHEMICAL ADDITIVES EMERGING PRESERVATION TECHNIQUES

14. Microorganisms (bacteria, yeasts, moulds, algea, viruses) Play an important ecological role in realizing geochemical cycles; convert reduced forms of carbon, nitrogen and sulfur in dead plants and animals to oxidized forms required by plants which in turn are consumed by animals

16. Plants have the ability to utilize energy from sunlight for synthesis of carbohydrates using CO2 and H2O in the air; photosynthesis. CO2 + H2O + (sunlight) ? (CH2O)n + O2 Organisms consume carbohydrates and convert them into energy through an enzymatic process called respiration. C6H12O6 + 6O2 ? 6CO2 + 6H2O + 673 Kcal

18. Enzymes (enzyme systems) Have well defined duties! Some of them function regularly in daily biochemical processes Some of them are programmed to perform duties in a later phase of the life cycle.

19. Typical life cycle of living tissues Development/growth (metabolic,biosynthetic reactions) ? Maturation ? Ripening ? Senescence (catabolic, degradative reactions) ? Deterioration

20. Rate of deterioration (spoilage) is subject to various environmental influences: Temperature Humidity Light Composition of atmosphere w.r.t. CO2, O2, ethylene and some other volatiles

21. Composition of Foods

22. Composition of foods is important in: Spoilage and desirable changes in foods Processing Preservation Nutritive value Organoleptic acceptance

23. Foods are generally water systems Dissolved: water-soluble carbohydrates (mono-, disaccharides), proteins, fatty acids, mineral salts, vitamins, pigments, flavor compounds. Colloidal state: most proteins, polysaccharides Emulsion: fats

24. For survival, living entities need to consume: Hydrogen, carbon, oxygen, nitrogen, calcium, phosphorus, sulfur, sodium, potassium, iron, and some minor elements

25. Typical plant and animal tissue compositions

26. Water ( largest constituent of most foods) Fruits and vegetables : 80-95% Meat : 74% Cheese : 37% Cereals : 12-20%

27. Functions of water in living cells and tissues It is a continuous matrix which holds the various food constituents either in dissolved, in colloidal or in emulsion form. It is a reactant in the photosynthesis reaction It is necessary for hydration, dehydration and hydrolysis reactions.

28. Functions of water in living cells and tissues Solvent properties of water are important for the existance of chemical reactions, breakdown reactions, reassimilation processes, ionization of chemical species. It serves in the transport of nutrients, metabolites and spent material into and out of the cells It takes part in many important biochemical reactions. It is necessary for the structural integrity of cells.