2C_HNF 141_Chapter 2_Postharvest_gc.pdf
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HNF 141 Food and Nutrition System Second Semester 2023-2024 Chapter 2: Food Availability Sub-Topic: Food Processing INTEGRATED FOOD AND NUTRITION SYSTEM : Subsystems and Stages 9 KEY THREE SUB...
HNF 141 Food and Nutrition System Second Semester 2023-2024 Chapter 2: Food Availability Sub-Topic: Food Processing INTEGRATED FOOD AND NUTRITION SYSTEM : Subsystems and Stages 9 KEY THREE SUB PROCESSES/ SYSTEMS STAGES Food Processing - any treatment (physical, chemical, and/or biological) applied to food from its point of origin and its point of consumption - includes all preliminary preparations, cookery processes and food preservation methods Preliminary processes may include: 1. Cleaning and sanitizing the food 2. Sorting to remove extraneous materials/ damaged portions, etc. 3. Disintegrating or other kind of physical process Cookery Process Refers to heating of food to: Increase digestibility Improve flavor Bring out color, aroma, & texture changes Kill microorganisms Preserve product Cooking Method 1. Boiling B²DS²PB² 2. Braising 3. Deep fat frying 4. Sautéing or pan frying 5. Steaming 6. Pressure cooking 7. Baking and roasting 8. Broiling or pan broiling POST-HARVESTING OPERATIONS - Primary processing procedures that start from harvest and end before secondary food processing or consumption - objective is to maintain the quality of fresh produce Are fruits and vegetables dead or alive after harvest? A fruit or vegetable undergoes: We are respiration - “breathes” alive!!! Please handle us with TLC. transpiration – “perspires” senescence – “grows old” deterioration – “dies” Fresh Produce } Harvested commodities that remain to be biologically active even after harvest } High in moisture content } Undergoes respiration and transpiration } Requires energy to maintain living state } Includes peeled or cut-up fruits and vegetables that are ready-to-eat or ready-to-cook Fresh Produce } Undergoes irreversible changes such as ripening, senescence and eventually DEATH of the tissue or organ } Quality attributes that irreversibly change after harvest include flavor, aroma, texture, color, nutritive value and wholesomeness } These changes are inevitable but can be delayed or slowed down by proper handling after harvest Triangle of Postharvest interaction Triangle of Postharvest interaction VMQ Variety Maturity Quality Triangle of Postharvest interaction TRA Temperature Relative Humidity Atmosphere Triangle of Postharvest interaction Insects Pests Pathogenic Organisms Environment 1. Temperature (most critical factor to maintain shelf-life) Tropical commodities must not be stored at temperatures lower than 12.50 C to prevent chilling injury 2. Relative Humidity 80-95% RH is favorable for fresh produce 3. Atmosphere O2 O2 R SL Too low O2 will result to fermentation CO2 Excessive CO2 R SL CO2 will result to abnormal ripening Ethylene – autocatalytically produced MAP: Modified Atmosphere Packaging O2 CO2 Enclosing in plastic bag O2 CO2 RH Shelf life Fresh produce has also been reported to harbor organisms causing food-borne illnesses like Salmonella, Shigella, Vibrio chloerae, Listerial monocytogenes and Bacillus cereus. Presence of these bacteria presents a greater health impact when found in ready-to-eat vegetables that are eaten raw or uncooked. Insects Pests Pathogenic Organisms Food Safety in Fresh Produce } Some crops are induced to synthesize substances that are toxic to humans as a result of poor handling. a. Solanin - associated with greening of potatoes b. Ipomeamarone - formed by sweet potato in response to microbial attack c. Isocoumarine - associated with bitterness in carrots Handling conditions affect nutritive value of fresh produce Ø 21-27% of protein in Chinese cabbage is lost after 9 hours at ambient; no more protein after2-3 days. Ø 10% decrease in vitamin C in leafy vegetables exposed to wind velocity of about 16 km/hr. Ø loss of vitamin C with severe moisture loss Ø 50% of vitamin C in pineapple during cold storage for 10 days; loss is highly correlated with chilling injury Ø Lycopene content is low in tomatoes stored above 25ºC Ø Carotene in grated carrot is reduced by 10-50% after 3 hours at room temperature Common Procedures in Packing House Operations https://link.springer.com/article/10.1007/s13197-019-04083-z/figures/2 Postharvest and Food Availability With appropriate postharvest handling, quantity and quality losses are reduced and can be translated to increased availability of food for human consumption. FOOD PRESERVATION Ø Refers to any treatment applied to convert highly perishable food into more stable forms. Ø Prevent food from microbial spoilage, meet the nutritional requirements of the consumer, facilitate better distribution of goods and to stabilize prices. Significance 1. Nutrition 2. Hygienic 3. Economic 4. Convenience 1. Thermal Processing – use of heat to preserve food Boiling n Pasteurizing Frying n Sterilizing Toasting Baking n Smoking Roasting n Drying 2. Drying and Dehydration – removal or evaporation of water to reduce water activity (aw) Natural Drying – with aid of sunlight Artificial Drying – use of driers or dehydrators 3. Low Temperature Preservation Refrigerated Storage – normally from 1º - 10ºC Frozen Storage - 0ºC and lower normally -18ºC Food Science and Preservation 4. Chemical Preservation Use of natural preservatives like salt, sugar, spices, and vinegar Use of organic compounds like lactic acid, acetic acid, citric acid Use of inorganic compounds like sulfur dioxide (SO2), sodium benzoate, nitrite/nitrates, sodium chloride Food Science and Preservation Others Use of radiations – ionizing radiations, ultraviolet rays Use of High Pressure – normally microbicidal Food Science and Preservation Food Safety Food poisoning/intoxication v Illness caused by ingestion of the toxin or poison present in the food. v Causes: 1. Microbiological - Botulism, Staphylococcal poisoning, Salmonellosis 2. Biological - toxins from animals & plants 3. Chemical Poisoning - chemicals like mercury, lead, etc. Food Safety Food bore infection v Infections transferred through food & do not necessarily grow in the food. v Examples: - Typhoid - dysentery Contributions of Food Processing Methods to Food and Nutrition Security 1. Ensures food safety 2. Prevents food quality losses and wastes (FQLW) 3. Extends shelf life 4. Increases the bioavailability of nutrients 5. Improves the sensory characteristics and functional properties PROCESSING (AND PACKAGING) AT DIFFERENT FOOD PRODUCTIONS SYSTEMS ACCORDING TO FOOD VALUE CHAIN TRADITIONAL FOOD SYSTEMS - Basic processing is available; limited packaging occurs MIXED FOOD SYSTEMS - Highly processed and packaged foods emerge and more accessible. These extend the shelf life of foods MODERN FOOD SYSTEMS - Many processed and packaged foods easily available, often cheap and convenient to eat, but sometimes “unhealthy”. THANK YOU!
