Introduction to Food Science and Technology 101

An Introductory course for students/beginners of food science an technology.

1. FST-101 (Theory) Introduction to Food Science and Technology Roshina Rabail M.Phil Human Nutrition and Dietetics M.Sc. Food and Nutrition Former Dietitian CMH Okara Cantt . & Shifa Int. Hospital Islamabad. 28/01/2019 Roshina Rabail (FST-101) 1

2. 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. Food Science 28/01/2019 Roshina Rabail (FST-101) 2

3. A Food Scientist studies the physical, microbiological, and chemical makeup of food. Depending on their area of specialization, Food Scientists may develop ways to process, preserve, package, or store food, according to industry and government specifications and regulations This study involves knowledge about: The nature of food and its composition. Its behaviour to different conditions (processing, preservation, storage). Causes of spoilage. Principles of processing and preservation methods. Improvement in food quality (attractive, safe, nutritious) Food Science 28/01/2019 Roshina Rabail (FST-101) 3

4. Food Science emerged as a discipline in early 1950’s. Broad discipline that holds many specializations: Food Engineering/Technology- engineering concepts start from the selection of raw food to its processing & preservation Food Microbiology- microbial ecology related to food, food spoilage Food and Nutrition- basic composition, structure, properties, effects of general health 28/01/2019 Roshina Rabail (FST-101) 4 Food Science

5. 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 food . Food Science and Technology is the application of physics, chemistry, microbiology, engineering and nutrition to the handling, processing and storage of food. Food Technology 28/01/2019 Roshina Rabail (FST-101) 5

6. Food Chemistry/Nutrition Food Engineering/Technology Food Microbiology Sensory Science Food Processing & Packaging Food Safety & Defence Product development Education & Careers Public Policy & regulation Sustainability Core areas in Food Science 28/01/2019 Roshina Rabail (FST-101) 6

7. Who can you work for??? Food processors/Food Industry Research Institutes Academia/Teaching Institutes Self-employed/Consultant Government/Non-government organizations Food service organizations Testing laboratory (For details consult chapter #1 Food Science and Technology by J.A. Awan ) Career Opportunities 28/01/2019 Roshina Rabail (FST-101) 7

8. Many disciplines from basic applied sciences are involved primarily in two different ways in the applications of Food Science. Scientific- involving physics, chemistry, biology & microbiology. Technological- involving engineering, processing, manufacturing, packaging, distribution etc. 28/01/2019 Roshina Rabail (FST-101) 8 Relationship with other disciplines

9. Major contributions of other disciplines in Food Science: Physics- Selection of raw & processed food material, Food pH, humidity, moisture contents, Food handling, packaging, transportation equipment. Heating, cooling & evaporation of food material. Chemistry- Chemical & biochemical nature of food Chemical reactions of metabolism, spoilage & processing Food analysis procedures 28/01/2019 Roshina Rabail (FST-101) 9 Relationship with other disciplines

10. Engineering- Conversion of raw products into finished ones Developing, processing, packaging and storing equipment and machinery Biology- Botany , plant pathology & genetics are involved in the breeding of new varieties Entomology, parasitology & zoology are involved in the growth of healthy plants and animals Human physiology involved in understanding how food will gets metabolised inside the body 28/01/2019 Roshina Rabail (FST-101) 10 Relationship with other disciplines

11. Microbiology- limiting food spoilage issues introducing beneficial cultures to develop products like yogurt, leavened bread, cheese, pickles, sausages etc . processing techniques i.e. pasteurization, sterilization, irradiation. Computer Science- involved in computing, calculating, recording and reporting data (For details consult chapter #1 Food Science and Technology by J.A. Awan ) 28/01/2019 Roshina Rabail (FST-101) 11 Relationship with other disciplines

12. In general food science and technology has: Enormous impact on the quality of human life Developed as world’s largest industry Processing unlimited variety of foods Transformation of agriculture from subsistence farming to industrial farming Production of food for more than 100 families Food freshness retention Deterioration and spoilage prevention Supplying good quality food to the distant areas Significance of Food Science and Technology 28/01/2019 Roshina Rabail (FST-101) 12

13. Regulating food supply: Regulating market prices in off season by proper storage and preservation of the excess food. Food supply during off season to meet the demand. Food supply to non-food producing areas. Food supply to far off places and ease in fruit and vegetable export. 28/01/2019 Roshina Rabail (FST-101) 13 Significance of Food Science and Technology

14. Consumer convenience in: Food cleaning and preparation Food storage Cooking time reduction Clean, safe, wholesome food over the counter Nutrient enriched food products Special food for special cases like diabetes, heart disorders, allergies etc . 28/01/2019 Roshina Rabail (FST-101) 14 Significance of Food Science and Technology

15. Scientific expeditions/journeys and travels: Processed, preserved & canned foods to be taken along on journeys North pole or Mount Everest Special foods for Astronauts Food served in Airlines Ships carry food for months 28/01/2019 Roshina Rabail (FST-101) 15 Significance of Food Science and Technology

16. Waste utilization & reduction in environmental pollution: 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 fermented products Production of Oils, fibres or pectins Production in herbal supplements or medicines 28/01/2019 Roshina Rabail (FST-101) 16 Significance of Food Science and Technology

17. Economic gains Food industry emerged as the biggest industry with: Enormous economic gains and profits Second major employer of labour in Pakistan Provision of high direct or indirect taxes to government Provision of foreign exchange through export business Supplying material to numerous allied industries producing chemicals, detergents, packaging, medicines etc. Transportation of raw and processed food items facilitate transportation department (For details consult chapter #5 Food Science and Technology by J.A. Awan ) 28/01/2019 Roshina Rabail (FST-101) 17 Significance of Food Science and Technology

18. Rise in Hunger Around the Globe : Hunger/undernourishment : dietary energy intakes below the minimum levels necessary to achieve and maintain a healthy weight . This chronic food deprivation has increased to nearly 821 million in 2017, from around 804 million in 2016. last 3 years have seen continuous increase in hunger About 1.2 billion people don’t get enough food 792 million people in developing countries 34 million in developed countries Global and national food and nutrition situation 28/01/2019 Roshina Rabail (FST-101) 18

19. Prevalence of Undernourishment( PoU ) : Africa~ highest PoU~21%of the population (more than 256 million people). South America~ PoU increased from 4.7% in 2014 to 5.0% in 2017. Asia~ PoU for 2017 is 11.4% (more than 515 million people). PoU decreasing trend seems to be slowing down significantly. Pakistan~ PoU was 19.9% in 2015, according to the World Bank collection of development indicators, compiled from officially recognized sources . Hunger in Pakistan Pakistan ranks 77th out of 109 on the Global Food Security Index. Six out of 10 Pakistanis are food insecure. Food insecurity persists although food production is sufficient to feed all Pakistanis. Almost half of women and children under five years of age are malnourished 28/01/2019 Roshina Rabail (FST-101) 19 Global and national food and nutrition situation

20. Nutrition Situation in Pakistan: Adults: Low energy and protein availability per capita 51% pregnant women-Anaemia 37%- Overall iron deficiency anaemia 46%- Vitamin A deficiency 69%- Vitamin D deficiency 47.6%- Zinc Deficiency Children <5: 62 %- Anaemia 43.8%- Iron deficiency anaemia 54%- Vitamin A deficiency 40%- Vitamin D deficiency 39%- Zinc deficiency 28/01/2019 Roshina Rabail (FST-101) 20 Global and national food and nutrition situation

21. Nutrition Situation Around the Globe: Pre-School Children About 160 million- severely malnourished 13 million- Xerophthalmia 500000 become partially or totally blind each year Child wasting: low weight for height (a strong predictor of mortality among children under five) In 2017, 7.5% ( 50.5 million) were reported to be affected by wasting (low weight for height) consequently putting them at a higher risk of mortality.` Child stunting: low height for age (impaired growth and development that children experience from poor nutrition, repeated infection, and inadequate psychosocial stimulation) The number of stunted children has shown a slight decline of 9% from 165.2 million in 2012 to 150.8 million in 2017, but still nearly one third of children under five in the developing world are stunted . 28/01/2019 Roshina Rabail (FST-101) 21 Global and national food and nutrition situation

22. Micronutrient deficiencies: L ack of essential vitamins and minerals required in small amounts by the body for proper growth and development. 1.5 billion people (28% world’s population)- anaemia This anaemia prevalence in women increased from 30.3 % in 2012 to 32.8% in 2016. 1 billion people – Iodine deficient 217 million people – goitre There is still a long road ahead to achieve the 2025 and 2030 targets for stunting, wasting, overweight, exclusive breastfeeding, anaemia in women and adult obesity 28/01/2019 Roshina Rabail (FST-101) 22 Global and national food and nutrition situation

23. Reasons behind Rise in Hunger: The no. of extreme climate-related disasters (extreme heat, droughts, floods and storms) has doubled since the early 1990s. Average 213/year occurred in 1990–2016 . Such disasters harm agricultural productivity. Drought only was responsible for more than 80% of the total damage and losses in agriculture, especially for the livestock and crop production subsectors . (For details consult chapter #2 Food Science and Technology by J.A. Awan ) 28/01/2019 Roshina Rabail (FST-101) 23 Global and national food and nutrition situation

24. Food is that which nourishes the body. Food may also be defined as anything ingested to meet the needs for energy, building, regulation and protection of the body. Nutrition includes everything that happens to food from the time it is eaten until it is used for various functions in the body . Adequate, optimum and good nutrition are expressions used to indicate that the supply of the essential nutrients is correct in amount and proportion . Nutritional status is the state of our body as a result of the foods consumed and their use by the body . Health as the ‘state of complete physical, mental and social well-being and not merely the absence of disease or infirmity. Malnutrition means an undesirable kind of nutrition leading to ill-health. It results from a lack , excess or imbalance of nutrients in the diet. It includes undernutrition and overnutrition . Food Terminology 28/01/2019 Roshina Rabail (FST-101) 24

25. Primarily there are two main sources of food: Plants Sources and Animal Sources Fishes are sometimes treated separately as a third group: Marine source: All kind of fish. 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. (For details consult chapter #1 Food Science and Technology by J.A. Awan ) Food sources 28/01/2019 Roshina Rabail (FST-101) 25

26. Chemically food is composed of following constituents: Carbohydrates Proteins Fats/Lipids Vitamins Minerals Water Food Constituents 28/01/2019 Roshina Rabail (FST-101) 26

27. Types of food constituents: On the basis of their functionality Energy giving: Carbohydrates, Proteins, Fats Growth & Body building: Proteins, Some minerals Maintenance: Vitamins, Minerals On the basis of requirement: Macronutrients: Carbohydrates, Proteins, Fats, Water Micronutrients: Vitamins, Minerals 28/01/2019 Roshina Rabail (FST-101) 27 Food Constituents

28. Carbohydrates: G eneral chemical formula C n (H 2 O) n O rganic compounds H ydrates of carbon (2:1 ratio of H and O) M ost abundant class of organic compounds on earth Carbohydrate Sources Carbohydrates are ingested in a variety of forms: starch from grains, glycogen from meat, and disaccharide and monosaccharide sugars from fruits and vegetables . Carbohydrates 28/01/2019 Roshina Rabail (FST-101) 28

29. Formation: Formed by the process photosynthesis 6CO 2 + 6H 2 O C 6 H 12 O 6 + 6O 2 Classification: Simple: monosaccharide, disaccharides Complex: oligosaccharides, polysaccharides 28/01/2019 Roshina Rabail (FST-101) 29 Carbohydrates

30. Simple : These can’t be hydrolysed any further Composed of 3 to 9 carbon atoms Only some trioses, pentoses and hexoses occur in nature Monosaccharide: 1sugar unit e.g. Glucose, fructose, galactose Disaccharide: 2 sugar units e.g. maltose, sucrose, lactose Carbohydrates 28/01/2019 Roshina Rabail (FST-101) 30

31. Complex: These can be hydrolysed into smaller simpler sugar units Composed of 3 or more than 3 sugar units attached by glycoside bonds Oligosaccharides: 3-7 sugar units e.g. raffinose , starchyose Poly Saccharides: more than 7 sugar units e.g. amylose(70-350), amylopectin(several hundreds) Starch, cellulose, glycogen, pectin, agar etc. 28/01/2019 Roshina Rabail (FST-101) 31 Carbohydrates

32. Carbohydrate metabolism Various biochemical processes responsible for the formation, breakdown and interconversion of carbohydrates in living organisms. During digestion, complex carbohydrates are broken down into monosaccharides , which can be absorbed by the body. The most important carbohydrate is glucose, a simple sugar (monosaccharide) that is metabolized by nearly all known organisms. Carbohydrate Utilization The monosaccharides that are absorbed in the small intestine are fructose , galactose , and glucose; the liver converts the first two into glucose . Excess glucose is stored as glycogen in the liver or is converted into fat and stored in adipose tissue . Carbohydrates 28/01/2019 Roshina Rabail (FST-101) 32

33. Carbohydrate Requirements The need for carbohydrates varies with a person's energy requirements ; the minimum requirement is unknown . An estimated intake of 125-175 grams of carbohydrate is needed daily to avoid protein breakdown. Energy share 50-60% from daily diet must be supplied from Carbohydrates Carbohydrates provide 16KJ or 3.75 Kcal/gram energy when metabolised Carbohydrates 28/01/2019 Roshina Rabail (FST-101) 33

34. Introduction Complex nitrogenous compounds Very high molecular weights About 2000 proteins exist in nature Composed of amino acids linked by peptide linkage Constituents of every living cell Participate in every aspect of cell metabolism Energy source providing 4 kcal (17 kJ ) per gram Body protein is approximately 19 % of flesh weight; 45% of this protein is present in muscle 28/01/2019 Roshina Rabail (FST-101) 34 Proteins

35. Classification Classified on the basis of heat: Coagulable Non- coagulable Classified on the basis of solubility: Globulins Albumins On the basis of functionality: Structural, homones , enzymes, antibiotics, transport, storage, toxins On the basis of composition: Simple Conjugated: phosphoproteins , lipoproteins, glycoproteins, nucleoprotein, flavoproteins , metalloproteins , chromoproteins 28/01/2019 Roshina Rabail (FST-101) 35 Proteins

36. Amino Acids: Building blocks of proteins 20 naturally occurring Low molecular weight compounds Found in different combinations in different proteins C haracterized by presence of a terminal (- COOH) & (- NH 2 ) Connected by peptide linkages; formed between the carboxyl and amino group of two adjacent amino acids. In addition, disulfide bonds may form between the sulfur moieties of two sulfur -containing amino acids in the polypeptide chain . May be alkaline, acidic or amphoteric in nature May be aromatic or aliphatic 28/01/2019 Roshina Rabail (FST-101) 36 Proteins

37. Amino acids classification Essential: Required in daily diet Synthesized in low quantity or cannot be synthesized in human body Non-essential: Not required in daily diet Can be synthesised in body from other amino acids 28/01/2019 Roshina Rabail (FST-101) 37 Proteins

38. Formation: Peptide linkage: Amino group of one amino acid links with acid group of second liberating a water molecule 2 dipeptide, 3 tripeptide , ….. Polypeptide Hundreds of such peptide bonds are present in protein 28/01/2019 Roshina Rabail (FST-101) 38 Proteins

39. Application: Functional/Nutritional/Chemical Functional Roles: Emulsification: Solubility: d rinks, beverages, soups Foaming: whipping creams, bread dough G elling ability: gelatin production, bread dough, yogurt Binding water and fat: Mayonnaise Nutritional Roles Provide energy for growth and maintenance of body Children require more protein as compared to adults Deficiency disease- Kwashiorkor 28/01/2019 Roshina Rabail (FST-101) 39 Protein

40. Other Chemical Roles: Takes part in growth, maintenance and repair in following ways: enzymes catalysing metabolic reactions structural proteins maintaining the shape of the cell hormones regulating cell activities, antibodies providing a defence mechanism contractile proteins transport proteins toxins and components of intracellular structures. 28/01/2019 Roshina Rabail (FST-101) 40 Protein

41. Proteins may form biologically significant compounds through conjugation with other molecules: chromo-proteins Lipoproteins Nucleoproteins Glucoproteins metalloproteins . Plasma proteins are also important in maintaining fluid and acid-base balance. Digestive processes depend upon acids, alkalis, enzymes from the stomach, intestinal glands and pancreas . 28/01/2019 Roshina Rabail (FST-101) 41 Protein

42. Sources Animal: Lean meat, poultry, fish, egg, milk, cheese, yogurt are rich protein sources Vegetable: Beans, pulses, nuts, seeds are good vegetative sources Cereals contain some amounts Vegetables and fruits generally poor sources 28/01/2019 Roshina Rabail (FST-101) 42 Protein

43. Lipids constitute a heterogeneous compounds related by their physical properties Insoluble in water Soluble in non-polar organic solvents alcohol , ether, benzene, chloroform and acetone Important dietary constituents High energy value Deliver fat soluble vitamins Include fatty acids , triglycerides, phospholipids, sphingolipids , sterols, waxes , glycolipids and lipoproteins. Lipids 28/01/2019 Roshina Rabail (FST-101) 43

44. Fats are esters of saturated or unsaturated fatty acids with glycerol; (Fatty acid+glycerol is called glyceride) Fats and oils are basically mixture of triglycerides. Fatty acids vary with respect to their size, number and position of double bonds found in the molecule. Classification: Classified by the number of carbon atoms: short chain (C4-6) medium chain (C8-12) long chain (C12 +) Classification by nutritional requirement Essential: Linoleic and - linolenic acid Non-essential: Palmitic , stearic, oleic acid. 28/01/2019 Roshina Rabail (FST-101) 44 Lipids

45. Classified by the saturation Saturated: devoid of double bonds general formula CH 3 (CH 2 ) n COOH, (n= 2 to 24) Stearic acid CH 3 (CH 2 ) 16 COOH Unsaturated: presence of double bonds Monounsaturated fatty acids: oleic acid (CH 3 (CH 2 ) 7 CH=CH(CH 2 ) 7 COOH ) Polyunsaturated fatty acids: Linolenic acid CH 3 CH 2 CH=CH . CH 2 CH=CH. CH 2 CH=CH(CH 2 ) 7 COOH 28/01/2019 Roshina Rabail (FST-101) 45 Lipids

46. Properties Saturated fats solids at room temperature Oils/unsaturated fats are liquid at room temperature Saturation of the unsaturated fatty acids by hydrogenation convert liquid oil into a hard fat (example , solid white vegetable shortening and margarine ) Mixing in water is dependent on emulsifier Milk (fat in water emulsion) Butter (water in fat emulsion) Fat/oils reacts with alkalis to form soaps Most of the fats melt between 30-40 ° C Smoke above 200°C 28/01/2019 Roshina Rabail (FST-101) 46 Lipids

47. Rancidity Oxidative rancidity Oxidative change results in changed odour due to liberating aldehyde, ketones or alcohols Oxidation is enhanced by the presence of light, high temperature, inorganic elements like iron & copper Antioxidants like tocopherols are added and fats/oils are stored in airtight containers and cool dark places. Hydrolytic rancidity Lipase hydrolysis of fats/oils Acid–glycerol bond is broken down Enzymes are destroyed or denatured by heat application 28/01/2019 Roshina Rabail (FST-101) 47 Lipids

48. Nutritional Significance Most concentrated source of energy Supply 9 kcal/g (37 kJ/g ) Increase palatability to food Enhance flavour and aroma Source of fat-soluble vitamins and essential fatty acids Required for growth , reproduction, skin integrity, maintenance of cell membranes. Stored in the form of adipose tissue to insulates and protects internal organs, maintain body temperature, while serving as a reserve source of energy. 28/01/2019 Roshina Rabail (FST-101) 48 Lipids

49. Sources Animal: Animal fats, butter, ghee Vegetable : Vegetable oils, oils of seeds and nuts, 28/01/2019 Roshina Rabail (FST-101) 49 Lipids

50. These are required in very small (micro) quantities in our daily diet. These include group of two constituents: Vitamins Minerals 28/01/2019 Roshina Rabail (FST-101) 50 Micro Food Constituents

51. A group of organic compounds essential in small quantities for the normal metabolism of other nutrients and maintenance of physiological well-being. Essential/vital for life Cannot be synthesized by the body Must be obtained from the diet Found in varying quantities in different foods No single food contains all of them in sufficient quantities Absence or relative deficiency of vitamins in the diet can lead to a characteristic deficiency state and disease 28/01/2019 Roshina Rabail (FST-101) 51 Vitamins

52. Classification: The vitamins are classified according to their solubility in water and fat solvents . Water Soluble Vitamins: vitamin B 1 (thiamin), vitamin B 2 (riboflavin), vitamin B 3 (niacin), biotin, vitamin B 6 (pyridoxine), pantothenic acid, folate, vitamin B 12 (cobalamin) and vitamin C (ascorbic acid). The water soluble vitamins are not stored to any great extent and therefore need to be included in the diet every day . Fat Soluble Vitamins: vitamin A(retinol), vitamin D ( calciferol ), vitamin E ( tocopherol ), and vitamin K ( Phylloquinone ) Fat soluble vitamins are stored in appreciable amounts in body tissues and, do not have to be supplied daily in the diet. 28/01/2019 Roshina Rabail (FST-101) 52 Vitamins

53. 28/01/2019 Roshina Rabail (FST-101) 53

54. Introduction: Mixture of compounds having Vitamin A activity Include retinol , retinal, retinyl ester or retinoic acid Retinol is a pale, viscous, fat soluble compound F airly heat stable but easily destroyed by oxidation Sources: Animal origin: Abundantly present in cod liver oil, beef liver, butter, cheese Plant origin: Present in the form of precursors carotenoids which may be converted into vitamin A; dark green leafy vegetables ( chlorophyll masks the yellow carotene color ), deep yellow vegetables , tomatoes and deep yellow fruit . Carotenoids closely related natural pigments include Beta-carotene , alpha-carotene , lutein and lycopene. Only beta and alpha carotene are precursors of retinol. 28/01/2019 Roshina Rabail (FST-101) 54 Fat Soluble Vitamins Vitamin A

55. Functions: Plays an important role in normal vision Essential for the integrity and normal growth of epithelial cells Required for proper growth and development of bones and teeth Important for the maintenance of membrane integrity and functions Anti-infective Deficiency diseases: hyperkeratinization , night blindness, Bitot’s spots, xerophthalmia , keratomalacia , and blindness. 28/01/2019 Roshina Rabail (FST-101) 55 Fat Soluble Vitamins Vitamin A

56. Introduction: Not strictly a vitamin, since it can be synthesized in the skin. Becomes essential/vital only when body fails to synthesise due to inadequate sunlight exposure. Its natural form is Cholecalciferol or Vit D3: a white crystalline compound that resembles to cholesterol. Stable to heat and processing. Functions: Regulation of calcium absorption Utilization of Calcium and Phosphorus Homeostasis Fat Soluble Vitamins Vitamin D 28/01/2019 Roshina Rabail (FST-101) 56

57. Deficiency Disease: Strict vegetarians are especially at risk of deficiency Rickets in children Osteomalacia in adults (softening of bones). Sources: There are relatively few sources of vitamin D Mostly found in animal origin of high fatty nature Oily fish , eggs , liver and butter providing modest amounts 28/01/2019 Roshina Rabail (FST-101) 57 Fat Soluble Vitamins Vitamin D

58. Introduction: Found in many foods Known as Tocopherols and Tocotrienols Seven different forms exist Most active is α- tocopherol Lost during processing Function: Lipid-soluble natural antioxidant that can be replaced by synthetic antioxidants Regulate reproductive function Maintain healthy immune system Prevent degeneration of tissues Protect hormones from oxidation 28/01/2019 Roshina Rabail (FST-101) 58 Fat Soluble Vitamins Vitamin E

59. Deficiency Disease: Dietary deficiency of vitamin E in human beings is unknown. Patients with severe fat malabsorption may suffer some forms of chronic liver disease Sources : Vegetable oils are rich sources of vitamin E. Significant amounts are found in nuts, seeds, eggs, milk, most green leafy vegetables and a variety of fish. 28/01/2019 Roshina Rabail (FST-101) 59 Fat Soluble Vitamins Vitamin E

60. Introduction: Discovered as a result of investigations into the cause of a bleeding disorder ( hemorrhagic disease) Three compounds have the biological activity of vitamin K; Phylloquinone K1: Yellow viscous oil, found in dietary origin (green leafy vegetables) Menaquinones K2: compounds synthesized by intestinal bacteria Menadione K3: synthetic compounds that can be metabolized to phylloquinone 28/01/2019 Roshina Rabail (FST-101) 60 Fat Soluble Vitamins Vitamin K

61. Sources: Green leafy vegetables like spinach cabbage, cauliflower and sprouts. In addition, soybean, rapeseed, cottonseed, and olive oils are relatively rich in vitamin K Functions: Anti-haemorrhagic and required for blood clotting Deficiency Disease: Liver damage Blood fails to clot 28/01/2019 Roshina Rabail (FST-101) 61 Fat Soluble Vitamins Vitamin K

62. Introduction: Thiamine- white solid widely distributed in foods readily lost by leaching into cooking water unstable to light Functions: Coenzyme in glucose metabolism E nergy-yielding metabolism at cellular level Takes part in nerve conduction therefore promotes healthy nervous system Promotes appetite and digestion 28/01/2019 Roshina Rabail (FST-101) 62 Water Soluble Vitamins Vitamin B1

63. Sources: Potatoes , whole-grain cereals, peas, dry beans, milk, yeast, meat, and fish are the major sources in most diets . Deficiency Disease: Beri Beri : weakness, palpitation of heart along with degeneration of nervous system and odema (wet beri beri ) 28/01/2019 Roshina Rabail (FST-101) 63 Water Soluble Vitamins Vitamin B1

64. Introduction: Riboflavin-yellow crystalline water soluble Occurs freely and as coenzyme FAD Deficiency is a significant public health problem in many areas of the world Fairly stable to heat but sensitive to light Sources: Milk and dairy products are important sources providing 25% or more of total riboflavin intake in most diets average riboflavin status in different countries reflects milk consumption to a considerable extent. Other rich sources are eggs, meat, fish, cheese, lean meat, liver and dark leafy vegetables. 28/01/2019 Roshina Rabail (FST-101) 64 Water Soluble Vitamins Vitamin B2

65. Functions: Takes part as coenzyme FAD in energy-yielding metabolism Healthy eyes and smooth skin Deficiency Disease: Glossitis : swollen tongue and lips magenta tongue Seborrheic dermatitis 28/01/2019 Roshina Rabail (FST-101) 65 Water Soluble Vitamins Vitamin B2

66. Introduction: Niacin is not strictly a vitamin, since it can be synthesized in the body from the essential amino acid tryptophan. Two compounds, nicotinic acid and nicotinamide have the biological activity of niacin . Was discovered as the curative and preventive factor for pellagra. Relatively resistant to heat, acid and alkali Sources: Liver, meat, poultry, fish, leafy vegetables, beans, cereals Chemical analysis reveals niacin in cereals (largely in the bran), but this is biologically unavailable. 28/01/2019 Roshina Rabail (FST-101) 66 Water Soluble Vitamins Vitamin B3

67. Functions: Takes part in cellular metabolism and energy yielding reactions Nicotinamide nucleotide coenzymes, NAD and NADP Deficiency disease: Pellagra: photosensitive dermatitis , like severe sunburn, typically with a butterfly like pattern of distribution over the face, affecting all parts of the skin that are exposed to sunlight. Advanced pellagra is also accompanied by dementia (more correctly a depressive psychosis ), and there may be diarrhea . Untreated pellagra is fatal. 28/01/2019 Roshina Rabail (FST-101) 67 Water Soluble Vitamins Vitamin B3

68. Introduction: The Latin word folium means “ leaf,” and the word folate from Italian means “foliage.” Folic acid - oxidized form of the vitamin found in fortified foods Folate - reduced form of the vitamin found naturally in foods and in biological tissues . Discovered during the search to cure the disorder megablastic anemia . Properties: Soluble in hot water Crystallizes in yellow-orange needles Less heat stable 28/01/2019 Roshina Rabail (FST-101) 68 Water Soluble Vitamins Folic Acid

69. Functions: Synthesis of nucleic acid Formation of red blood cells I nvolved in the metabolism of several amino acids, including histidine , serine, glycine, and methionine. Deficiency Disease: Megaloblastic Anaemia Sources: Liver, kidney, green leafy vegetables, okra, peanuts, 28/01/2019 Roshina Rabail (FST-101) 69 Water Soluble Vitamins Folic Acid

70. Introduction: The Greek word pantos means “everywhere” It is widely distributed in food sources of all plant and animal origins. Known as Pantothenic acid Occurs in foods in free and bound forms. About 85% of in food occurs bound as a component of coenzyme A. Properties: Yellow viscous oil, soluble in water More stable in pH ranges 4-7 Less heat resistants and lost during thermic processing. 28/01/2019 Roshina Rabail (FST-101) 70 Water Soluble Vitamins Vitamin B5

71. Deficiency disease: A deficiency is quite unlikely. “Burning feet syndrome ”: numbness of the toes and a sensation of burning in the feet. Sources: Meats (particularly liver), egg yolk , legumes, whole-grain cereals, potatoes, mushrooms , broccoli , and avocados, among other foods, are good sources of the vitamin. 28/01/2019 Roshina Rabail (FST-101) 71 Water Soluble Vitamins Vitamin B5

72. Introduction: Pyridoxine represents the alcohol form, pyridoxal the aldehyde form , and pyridoxamine the amine form . Functions: Acts as coenzyme Deficiency Disease: Signs of vitamin B 6 deficiency include sleepiness, fatigue , cheilosis , glossitis , and stomatitis in adults. Neurological problems and convulsions in infants. Microcytic anemia due to impaired heme synthesis . 28/01/2019 Roshina Rabail (FST-101) 72 Water Soluble Vitamins Vitamin B6

73. Sources: Pyridoxine-found almost exclusively in plant foods. Pyridoxal phosphate and pyridoxamine phosphate are found primarily in animal products. Good sources are meats, whole-grain products, vegetables, some fruits (e.g., bananas), and nuts. 28/01/2019 Roshina Rabail (FST-101) 73 Water Soluble Vitamins Vitamin B6

74. Introduction: Discovered on investigating the cause of “ egg white injury”. Eating raw eggs was known to result in hair loss, dermatitis, and various neuromuscular problems. Combines with avidin (raw egg white protein) which makes its unavailable . Later it was called vitamin H (the H refers to haut in German and means “skin”) as well as vitamin B7 . Properties: Crystallizes in needles in water. Heat and light stable Favourable pH range 5-8 28/01/2019 Roshina Rabail (FST-101) 74 Water Soluble Vitamins Vitamin B7

75. Functions: Takes part as coenzyme in carboxylation and transcarboxylation reactions Deficiency: Lethargy, depression , hallucinations, muscle pain , paresthesia in extremities , anorexia, nausea, alopecia (hair loss), and scaly , red dermatitis. Sources: liver, soybeans, and egg yolk, as well as cereals, legumes, and nuts. Can also be produced by intestinal bacteria. 28/01/2019 Roshina Rabail (FST-101) 75 Water Soluble Vitamins Vitamin B7

76. Introduction: Vitamin B12 also called cyanocobalamin . Properties: Red coloured water soluble vitamin Stable in pH range 4-6 Fairly heat stable Functions: Acts as coenzyme 28/01/2019 Roshina Rabail (FST-101) 76 Water Soluble Vitamins Vitamin B12

77. Deficiency Disease: Deficiency occurs mostly in strict vegeterians Deficiency of vitamin B12, like that of folate , results in megaloblastic macrocytic anemia Sources: Found only in animal origin The best sources of the cobalamins are meat and meat products, poultry, fish, shellfish (especially clams and oysters), and eggs (especially the yolk). Mil k and milk products such as cheese, cottage cheese, and yogurt contain less of the vitamin 28/01/2019 Roshina Rabail (FST-101) 77 Water Soluble Vitamins Vitamin B12

78. Introduction: White crystalline substance Destroyed by heat, oxidation, light Lost during peeling, trimming, cooking. Functions: Ascorbic acid is required in several reactions involved in body processes , including collagen synthesis, carnitine synthesis, tyrosine synthesis and catabolism, and neurotransmitter synthesis . It takes part as a reducing agent and important antioxidant in the body. Strengthen blood vessels, Aids iron absorption, Healing of wounds 28/01/2019 Roshina Rabail (FST-101) 78 Water Soluble Vitamins Vitamin C

79. Deficiency Disease: Scurvy Sources: The best food sources of vitamin C include asparagus, papaya, oranges, orange juice, cantaloupe, cauliflower, broccoli, Brussels sprouts, green peppers, grapefruit, grapefruit juice, kale, lemons, and strawberries. Of these foods, citrus products are most commonly cited as significant sources of the vitamin. 28/01/2019 Roshina Rabail (FST-101) 79 Water Soluble Vitamins Vitamin C

80. Introduction: Very important in normal nutrition and metabolism Constitute only about 4% of total body weight . Functions: Their functions are many and varied . Two general functions include building and regulating They provide the medium essential for normal cellular activity. They maintain electrolyte balance/osmotic properties of body fluids. Provide hardness to bones and teeth. Function as obligatory cofactors in metallo enzymes. Classified by their occurrence in the Body: Macrominerals : required in amounts >100 mg/day Microminerals : required less than macrominerals . The major minerals of the human body: calcium , phosphorus , magnesium , sodium, potassium, and chloride. Minerals 28/01/2019 Roshina Rabail (FST-101) 80

81. Nutritionists categorize food on the basis of their consumption pattern or functions Chemists categorize them on the basis of chemical nature Food processor categorize food on possibilities to increasing its shelf life which include perishability and pH values Classification of food Based on  Perishability. Some  foods have longer shelf life than others.  Perishability  refers to the quickness with which a food gets spoilt . 28/01/2019 Roshina Rabail (FST-101) 81 Classification of Food

82. 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 3 years 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. 28/01/2019 Roshina Rabail (FST-101) 82 Classification on the basis of Perishability

83. 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. 28/01/2019 Roshina Rabail (FST-101) 83 Classification on the basis of Perishability

84. 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. 28/01/2019 Roshina Rabail (FST-101) 84 Classification on the basis of Perishability

85. In chemistry, pH 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. pH determine the rate of microbial survivors. It gives information on: Food spoilage organism Food poisoning microorganism Choice of heat processing temperatures 28/01/2019 Roshina Rabail (FST-101) 85 Classification on the basis of pH

86. Divided into four categories: High Acid Acid Medium acid 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 28/01/2019 Roshina Rabail (FST-101) 86 Classification on the basis of pH

87. 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 28/01/2019 Roshina Rabail (FST-101) 87 Classification on the basis of pH

88. Medium Acid Foods: pH 5-4.5 Includes most meats and vegetable mixtures Same spoilage organisms as before Low Acid Foods: pH 5 or above 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. 28/01/2019 Roshina Rabail (FST-101) 88 Classification on the basis of pH

89. Food Spoilage: Food spoilage is the process leading to a product becoming either undesirable or unacceptable for human consumption (with associated changes involving alterations in taste, smell, appearance or texture).  Food spoilage may be caused by a variety of mechanisms, including microbial, chemical and physical reactions, Deterioration: Detrimental changes in the quality of food. 28/01/2019 Roshina Rabail (FST-101) 89 Mode of Food Spoilage

90. 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. 28/01/2019 Roshina Rabail (FST-101) 90 Mode of Food Spoilage

91. Must be kept in bags/silos because can get damaged/spoiled if not stored properly Mechanical agents : Insects, pests, rodents, birds can cause damage and leave their excreta/ sheddings which make food unfit for health Physical agents : Loss or gain of moisture during storage due to temperature change and humidity level in atmosphere can effect the quality of grains. Microorganisms : Gain in moisture can facilitate bacteria, yeast and moulds multiplication producing mycotoxins . Autolysis: Further gain in moisture can facilitate the germination of seed. 28/01/2019 Roshina Rabail (FST-101) 91 Mode of Spoilage of Stable Foods:

92. Must be stored at cool, ventilated places. Mechanical agents : Insects, pests and rodents can bring loss in quantity and quality, ultimately open ways for microbial infestation. Physical agents : Loss in moisture can lead to shrinkage, weight reduction. Autolysis : Enzymatic activities can lead to softening, sprouting. Microorganisms : Attack on damaged/softened food commodities include bacterial soft rot and black mould. 28/01/2019 Roshina Rabail (FST-101) 92 Mode of Spoilage of Semi-Perishable Foods :

93. Mechanical agents : Insects, pests, rodents and birds can bring loss in quantity and quality, ultimately open ways for microbial infestation. Physical agents : Loss in moisture can lead to shrinkage, weight reduction, high temperature can leads to wilting. Autolysis : Most fruits and vegetables got spoiled due to ripening ( a series of complex chemical and biochemical reactions catalysed by enzymes) which results in softening or wilting. Fruits and vegetables covered by an insoluble stiff covering shield made of protopectin which can be damaged/broken due to ripening/wilting of food. Microorganisms : Attack on damaged/softened food commodities. Meat undergoes putrefaction and give off odour, milk got curdle. 28/01/2019 Roshina Rabail (FST-101) 93 Mode of Spoilage of Perishable Foods:

94. Chemically induced autolysis Self destruction of living cells Caused by chemical compounds in food or enzymes Auto-oxidation in fats and oils Oxidative rancidity initiated by short wavelength light Uptake of oxygen by unsaturated systems and changing lipid radicals to peroxiradicals Reaction with hydrogen forming hydroperoxides Critically high cccumulation of hydroperoxides leads to their breakdown into aldehydes, ketones and acids ( orourous /off flavour compounds) Accelerated by certain metals (copper), light, high temperature Changes in meat colour Deteriorative oxidation in meat results in off colour Oxidation changes myoglobin (purple coloured muscle pigment) to oxymyoglobin (bright red) Further oxidation of oxymyoglobin changes it to metmyoglobin (brown colour) 28/01/2019 Roshina Rabail (FST-101) 94 Spoilage by Autolysis

95. Non-enzymatic browning Can be due to food interaction with metals, water, cooking equipment, pH change or cooking temperature etc. Millard Reaction A chemical   reaction between an amino acid from protein with a carbonyl group from reducing sugar. Brown nitrogenous polymers are formed Limits shelf life of various fruits, vegetables and juices Mostly undesirable nut only desired in roasting nuts, meat, snacks and some bakery items. Caramelization The temperature-dependent oxidation of sugar which involves of removal of water from a sugar (such as sucrose or glucose) followed by isomerization and polymerisation steps Used extensively in cooking for the resulting nutty flavor and brown color . Changes in ascorbic acid Stored fruit juices changes to unfavourable brown colour due to oxidation of L-ascorbic acid to D- dehydro -ascorbic acid 28/01/2019 Roshina Rabail (FST-101) 95 Spoilage by Autolysis

96. Enzyme induced autolysis Enzymatic rancidity Hydrolysis of fats resulting in liberation of free fatty acids and glycerol Off flavour in fats and oils Putrefaction in fish Fish gut microorganisms promote this fish tissue autolysis resulting in typical spoiled fish odour due to ammonia like substances Enzymatic browning Desirable colour of raisins, prunes, coffee Polyphenols converted to quinones resulting brown pigment 28/01/2019 Roshina Rabail (FST-101) 96 Spoilage by Autolysis

97. Following are the Spoilage agents: Enzymes Microorganisms Moulds Yeast Bacteria Other Factors affecting microorganisms Food Water Oxygen Temperature pH Insects, Rodents, Pests and Birds Physical Factors 28/01/2019 Roshina Rabail (FST-101) 97 Spoilage Agents

98. Harmful Effect: Enzymes are responsible for spoilage/deterioration of food due to enzymatic autolysis in fresh fruits and vegetables and ultimately decrease their shelf life. Beneficial Effects: Enzymes are biocatalysts that Accelerate the rate of chemical reactions Don't undergo any change in themselves Enzymes are proteins in nature that Are synthesized in living cells Acts in vivo and in vitro 28/01/2019 Roshina Rabail (FST-101) 98 Enzymes

99. Enzymes are used in food industry for Pectolytic enzymes in fruit juice industry for clarification & pigment extraction of fruit juices uses Tenderization of meat Manufacturing various dairy products like cheese Bread industry use amylolytic enzymes To improve the quality and quantity during olive oil extraction Production of maltose Saccharification of starches requires amylases Saccharification of cellulose requires cellulases Production of alcoholic beverages 28/01/2019 Roshina Rabail (FST-101) 99 Enzymes

100. Enzymes are classified into 6 groups on the basis of the reaction they catalyze : Oxidoreductases Oxidation/reduction reactions, e.g. cytochrome oxidase Transferases Transfer of a functional group, e.g. transaminase Hydrolases Hydrolytic reactions (hydrolysis in the presence of water) , e.g. esterases Lyases Addition or removal of a group by deletion or formation of a double bond , e.g. fumerase Isomerases Intramolecular rearrangement, e.g. phosphohexose isomerase Ligases Formation of covalent bond using energy , e.g. pyruvate carboxylase 28/01/2019 Roshina Rabail (FST-101) 100 Enzyme Classification

101. Effect of pH Enzyme mediated reactions require specific narrow pH range Below this pH range enzymes are inactive Above this pH range enzymes are denatured Selection of natural pH would allow microbial attack Low pH is preferred for food preservation by limiting microbial attack and inactivating enzymes, e.g. pickling Effect of Temperature Influence rate of enzyme activity Most enzymes active below 50ºC High or low temperature slow down the activity Lower temperatures of refrigerator or freezing inactivates enzymes High temperature usually 70-80ºC denatures enzyme, e.g. Blanching Effect of Concentration Rate of enzyme activity id directly proportional to their concentration 28/01/2019 Roshina Rabail (FST-101) 101 Enzyme Efficiency

102. Microorganisms are ubiquitous Found everywhere in soil, water, air, plants, animals, humans Only not present in tissues of healthy plants and animals Chief agents responsible for spoilage of food Categorized into Moulds, Yeasts, Bacteria 28/01/2019 Roshina Rabail (FST-101) 102 Microorganisms

103. A mould is a fungus that grows in the form of multicellular filaments called hyphae. These can be septate (can divide) or aseptate (cant divide). Forms a network called mycelium and produce spores. Spores released can spread to germinate on new surfaces. Used in production of various food products, organic acids, antibiotics, vitamins and enzymes Grow rapidly in warm and damp climates, tropical regions with moderate to heavy rains Aerobic in nature, therefore only grow over the surfaces of foods like grains, tubers, bread, jam, fruits etc. 28/01/2019 Roshina Rabail (FST-101) 103 Moulds

104. Examples are: Aspergillus Can grow at fairly on foods with low water contents Mucor Moderate temperature and high humidity Penicillium Low temperature Can be prevented by controlling temperature, moisture contents, keeping food in airtight containers Can be killed at high temperature above 100ºC. 28/01/2019 Roshina Rabail (FST-101) 104 Moulds

105. Yeasts are eukaryotic, single, round-celled fungi. Divide rapidly by budding or binary fission. Require low pH and moisture higher than moulds. The first yeast originated hundreds of millions of years ago. 1,500 species are currently identified. They are estimated to constitute 1% of all described fungal species.  In contrast, fungi that can adopt a single-celled growth habit are called yeasts . Used in manufacturing of bread, enzymes, vitamins, juices, jam, jellies, non alcoholic beverages etc. Can be seen over the surfaces of fruits. Can be destroyed at high temperatures by boiling or pasteurization. 28/01/2019 Roshina Rabail (FST-101) 105 Yeasts

106. Microscopic Single-celled P rokaryotes lacks a membrane-bound nucleus or any other membrane-bound organelle Advantages : Used in production of: Organic acids, enzymes, antibiotics, vitamins, amino acids Yogurt, fermented meat, milk, fruits, vegetables Bacteria living inside gut helps: Produce some vitamins from B-complex. Digest cellulose in ruminants Disadvantages: Food Spoilage, Food born diseases, Food poisoning, Infections etc., 28/01/2019 Roshina Rabail (FST-101) 106 Bacteria

107. Classification on the basis of shape: Round-   cocci (singular: coccus ) Cylindrical/capsule-bacilli (singular: bacillus) Long coiled- spirilla (singular: spirillum ) Short curved-vibrio Classification on the basis of temperature needs: Thermophilic : hot temperature loving (45-55ºC) Mesophilic : Room temperature loving (20-30ºC) Psychrophilic: Cold temperature loving (4-10ºC ) Classified on the basis of Oxygen requirement: Aerobic: Needs oxygen Anaerobic: Doesn’t need oxygen 28/01/2019 Roshina Rabail (FST-101) 107 Bacteria

108. Diverse in nature i.e. present in air , soil, water, human/animal guts Possess cell wall that may be covered with a protective covering capsule or slime layer. More difficult to kill as compared to moulds and yeast Require high temperature or high acid treatments to kill Methods adopted are Boiling, cooking, Pasteurization and sterilization Examples of toxic bacteria are: clostridium botulinum , salmonella, shigella Factors affecting the growth of microorganisms: Food Temperature Moisture pH Oxygen 28/01/2019 Roshina Rabail (FST-101) 108 Bacteria

109. Insects: Have 6 legs and hard outer skin/cuticle Life cycle consists of various forms like eggs, larva, pupa, adult Examples are: weevils, beetles, moths Rodents: Mouse, rat, squirrel, rabbit Cannot survive in cold stores Eat and destroy food with filth Can be a carrier of different diseases like plaque, salmonella Birds: Source of filth and contamination in fruits and crops 28/01/2019 Roshina Rabail (FST-101) 109 Insects, Rodents, Birds

110. Losses during harvesting, processing, storage Rains and storms Hot or cold temperature Undesirable changes in light 28/01/2019 Roshina Rabail (FST-101) 110 Physical Factors

111. Chemical spoilage by autolysis may be prevented or delayed by the destruction or inactivation of enzymes or chemical molecules. Microbial spoilage may be prevented or delayed by prohibiting microbial entry, their physical removal, hindering their growth and activity or even destroying them by using specialized techniques. Mechanical spoilage caused by insects, rodents and birds can be controlled or prevented by proper packaging. Physical spoilage caused by the handling during processing and storage can be reduced or prevented by development of optimal processing and storage techniques. 28/01/2019 Roshina Rabail (FST-101) 111 Principles of food preservation

112. Prevention or delay of autolysis pH Low pH by using organic acids e.g., pickles High/low temperature High temperature like 100ºC for few seconds to few minutes- blanching Low temperature involves refrigeration or freezing Moisture Moisture is required for biochemical reaction by enzymes Removal of moisture by sun drying, dehydration, concentration, evaporation Good manufacturing practices to lower chemical autolysis During manufacturing use of appropriate temperature, proper packaging and storage 28/01/2019 Roshina Rabail (FST-101) 112 Prevention or delay of autolysis

113. Prevention or delay of microbial activity Keeping microorganisms out Skin, peel, husk, shells provide protection Wax coating, canning, glass packaging, can be done to keep this covering intact Removal of microorganisms Washing, trimming, filtration techniques are used Creating unfavourable condition Anaerobic condition by vacuuming in canning Removal of moisture or water binding using sugars or glycerines (humectants) Use of chemicals like benzoic acid, sodium benzoate, lactic acid Low pH by acids in pickling Use of unfavourable temperature Destruction of microorganisms High temperature: boiling, blanching, steaming, roasting, cooking Pasteurization: 65-88ºC Sterilization,: much higher temperature , above 100 ºC Chemicals, ultraviolet rays for irradiation of food 28/01/2019 Roshina Rabail (FST-101) 113 Prevention or delay of microbial activity

114. Control of pest activities Insects Fumigation Insect proof containers Long acting insecticides Insect repellents Insect predators Impact based instrument to kill eggs Rise in temperature or infrared devices Rodents Systemic control of rodents include poison baits, rat-traps Difficult invasion storing technique Birds Noise making dummies of animal or human shapes Screen prevention 28/01/2019 Roshina Rabail (FST-101) 114 Control of pest activities

115. Reduction in physical defects Improper surface drying can be avoided using ultraviolet lamps Improper crystallization Other defects include humidity control 28/01/2019 Roshina Rabail (FST-101) 115 Reduction in physical defects