F3+Shelf+life

When the food no longer maintains the expected quality desired by the consumer, because of changes in flavor, smell, texture, appearance or microbial spoilage. ** 3.2 Chemical Factors that Affect Shelf Life: **
 * 3.1 Shelf Life: **

** 3.3 Rancidity in Fats: ** Perception of flavor in lipids: when the flavor seems “off” (disagreeable smell, taste, texture or appearance.) ** 3.4 Two kinds of rancidity: Hydrolytic and Oxidative ** Hydrolytic Rancidity: Breaking down of a lipid into its component fatty acids Eg. Fat+H2O à fatty acids + glycerol (INSERT PICTURE) This occurs more rapidly with heat, moisture, and enzymes such as lipase. Deep frying (because of the water and heat) increases the rate of hydrolysis Examples of fatty acids in foods causing rancidity: Oxidative Rancidity: Fatty acid chains are oxidized, typically by the addition of oxygen across the C=C bond of the unsaturated fatty acid. Eg. Oily fish (herring and mackerel) have an high amount of unsaturated fatty acids, therefore a high chance of oxidation Light (photo-oxidation) and enzymes are catalysts ** 3.6 Prolonging Shelf life: ** Typical methods of preserving-fermentation, adding sugar, pickling with vinegar, salting, drying and smoking. ** 3.5 Specific Methods ** Processing:
 * Factor || What it does || Ideal state || Additional Info ||
 * Change in Water content || loss of nutrients, rancidity, browning || Low water content || Dry food + water = more likely to spoil ||
 * Change in pH || Loss of nutrients, browning, change of color, flavor || Low pH ||  ||
 * Light || Leads to rancidity, loss of vitamins, fading of natural colors || Low to no light (depends on food) ||   ||
 * Temperature || Rate of spoilage || Low temperature || High temp=high rate ||
 * Exposure to air || Rate of oxidation =browning, changes in flavor color and loss of nutrients || Low to no air exposure ||  ||
 * Fatty Acid: (formulas are in textbook) || Where it is found/What it does ||
 * Butanoic acid, hexanoic acid, octanoic acid || Milk ||
 * Palmitic acid, stearic acid, oleic acid || Chocolate-oily or fatty flavor ||
 * Lauric acid || Palm and coconut oil (in cocoa butter solutions) a fatty flavor ||
 * Butanoic acid || Butter ||
 * Method || What it does || Application of method ||
 * Refrigeration and freezing || Limiting lipase hydrolysis || Dairy products ||
 * Reducing light levels || Reducing oxidation || Colored glass, dark places ||
 * Radiation || To destroy microorganism || Gamma or x-ray ||

Packaging: sealing in tin cans || or Hermetic Sealing ||
 * Method || What it does || Application of method ||
 * Covering food || Reduce contact with oxygen || Using an inert gas
 * Sealing || Reduce contact with oxygen || Using low gas-permeability packaging,
 * Filling jars completely || Reduce contact with oxygen ||  ||

Additives:

Sodium hydorgen sulfite Citris acid || Delay non-ensymic browning || Potassium nitrate Nitrate || Curing meat fixing color inhibiting microorganisms || Benzoic acid || Antimicrobial agents in fruit juices, carbonated drinks, pickles and sauerkraut || Propanoic acid Calsium Propanoate Sodium Propanoate || Delaying mold and bacteria growth in breads and cheese || Benzoic acid || Delaying mold and bacteria growth in pickled meats, fish products to add flavor || ** 3.7 Antioxidant ** Substance that delays the onset or slows the rate of oxidation used to extend shelf life ** 3.8 Naturally Occurring Antioxidants: ** ** 3.9 Structural features of Synthetic Antioxidants: ** BHA (hutylated hydroxyanisole): 3-tert-butyl-4-hydroxayaisole and 2-tert-butyl-4-hydroxanisole BHT (butylated hydroxytoluene) : PG (propyl gallete) : THBP (2,4,5-trihydroxybutyrophenone : TBHQ (tert-butylhydroquinone) :  All examples contain a phenolic group (OH connected to benzene ring) many contain a tertiary butyl group C(CH3)3. Both of these groups react with and remove the free radicals involved in the oxidation of the food and therefore prolong shelf life.   ** 3.10 Advantages vs. Disadvantages of Natural and Synthetic Antioxidants **  Natural Occurring Antioxidants:
 * Additive || What it does ||
 * Sodium sulfate
 * Sodium nitrate
 * Sodium benzoate
 * Sorbic acid
 * Ethanoic acid
 * Antioxidant || Found in: ||
 * Vitamin C (ascorbic acid) || Citris fruits, green peppers, broccoli, green leafy vegetables, straberries, red currants, potatoes ||
 * Vitamin E (tocopherols) || Wheat germ, nuts, seeds, whole grains, green leafy vegetables, vegetable oil (canola), soya beans ||
 * B-Carotene || Carrots, squash, broccoli, sweet potatoes, tomatoes, kale, canalope, melon, peaches and apricots ||
 * Selenium || Fish, shelfish, red meat, grains, chicken, garlic ||


 * Antioxidant || Found in: ||
 * Vitamin C (ascorbic acid) || Citris fruits, green peppers, broccoli, green leafy vegetables, straberries, red currants, potatoes ||
 * Vitamin E (tocopherols) || Wheat germ, nuts, seeds, whole grains, green leafy vegetables, vegetable oil (canola), soya beans ||
 * B-Carotene || Carrots, squash, broccoli, sweet potatoes, tomatoes, kale, canalope, melon, peaches and apricots ||
 * Selenium || Fish, shelfish, red meat, grains, chicken, garlic ||

Advantages:  · Producing hormones and collagen ||  · Acts as a precursor for Vitamin A ||
 * Vitamin C ||  · reduce the risk of cancer and heart disease (inhibiting the formation of free radicals)
 * Vitamin E ||  · reduce the risk of cancer and heart disease (inhibiting the formation of free radicals)  ||
 * Carotenoids ||  · reduce the risk of cancer and heart disease (inhibiting the formation of free radicals) ||
 * B-Carotene ||  · Additive in margarine for the yellow color

Disadvantages: Synthetic:  o Perception to be less safe  o Need to be regulated by policies (policies regarding labeling and safe use of food additives can be difficult to implement and monitor) Natural:  o Can be less effective  o Can create an aftertaste

** 3.11 List some antioxidant examples with their health benefits:   **   Green tea, oregano, blueberries, cranberries, dark chocolate  Health benefits=lowering levels of LDL cholesterol and blood sugar, reducing high blood pressure and preventing cancerous cell development.