ANSC 424 Exam 2 | Verified with 100% Correct Answers

ANSC 424 Exam 2 | Verified with 100% Correct Answers What are the steps of extrusion? formulation grinding premixing extrusion drying coating packaging What four things are necessary for the extrusion process? moisture pressure temperature mechanical shear How does extrusion improve nutritional quality of the feed? increases digestibility of starch and protein decreases ANF What are benefits of extrusion? increases nutritional quality sterilizes product improves texture What is the importance of the grinding step in extrusion? uniform particle size even moisture uptake for proper cooking How are carbohydrates a functional ingredient in extrusion? used as binder heat + moisture + time = gelatinization starch most functional carb fiber has low functionality and negative effect on texture and expansion How are proteins a functional ingredient in extrusion? low functionality, actually negative effect on flow, binding, expansion - more dense product plant and fresh meat are more functional How are lipids a functional ingredient in extrusion? higher levels are negative decrease friction which decreases flow thru and expansion and texture development What are other functional ingredients in extrusion? humectants help protect from moisture spoilage reducing pH helps also protect against spoilage What are examples of humectants? sugar, syrups, salts, propylene glycol, glycerin What is the purpose of the preconditioner in extrusion? hydrate and heat and mix partial cooking before extrusion increases production capacity, decreases extrusion screw wear, decreases mechanical energy input, increases thermal energy input What are equipment considerations for extrusion? feed delivery system (agitator yes or no?) preconditioner (use if in-barrel moisture is 18%) extruder barrel and components die and knife dryer and coater What are the two main types of feed delivery systems? volumetric gravimetric What are the qualities of a volumetric feed delivery system? manual control of speed of feeder low cost simple rate affected by density of material What are the qualities of the gravimetric feed system? automatic control not affected by material density complex and costly more uniform product What is the purpose of the screw in the extruder? conveys product through adds pressure, moisture, heat What type of energy is required to turn the extruder screw? mechanical What in extrusion is the main cause of the change in the product? mechanical energy Three important factors in the drying step of extrusion? temp, time, airflow If too hot or too cold in the drying step of extrusion what happens? hot = burnt, brittle, mold inside cold = not dry, chewy, short shelf-life If too much airflow or not enough during the drying step of extrusion what happens? too much = short circuit, not dry product, blow product too little = clumpy, uneven drying, not dry How does drying temperature affect the flavor and physical characteristics of the product in extrusion? higher dry temp = "baked" product flavor lower dry temp = denser product Two types of dryers used in extrusion? continuous batch continuous conveyor What are the qualities of a continuous batch dryer in extrusion? continuous turning moderate handling save floor space What are the qualities of a continuous conveyor dryer in extrusion? uniform drying gentle handling multiple passes Conduction vs convection? conduction the cold point is in the middle of the container - for loaf products convection heat moves in a more fluid motion, cold point near middle of container bottom - for liquid products What are the functions of the die in extrusion? cook (starch gelatinization) control bulk density texture development control fat absorption control size and shape What can the die in extrusion affect? palatability food prehension feeding behavior Types of cooling systems in extrusion? continuous batch (can be drum or vacuum) Why would one use a vacuum cooling system in extrusion? if greater fat content is required in the final product What is the purpose of retort? destroy bacteria FDA regulates for canned pet foods What is the general process of retort? fill can heat to 110-121 C at middle of product holding time Does commercial sterilization destroy all microorganisms? No What does commercial sterilization do? any remaining microorganisms cannot grow increase shelf life avoids intense heat treatment that may affect palatability and nutrients What four factors affect microbial growth? water pH oxygen temperature What is the level of water activity required for microorganisms to grow? 0.95 anything less than 0.85 is goal for canned food What are the classifications of microbes based on temperature? thermophiles, mesophiles, psychrotrophs What is the pH that separates acidic vs low acid foods? 4.6 What are the classifications of microbes based on oxygen requirements? aerobe anaerobe facultative anaerobe What are steps in feed manufacturing where food can get contaminated? pre processing/retort if retort does not occur or is inadequate during cooling rupture of seal (leaker spoilage) internal corrosion (chemical contamination) overfilling and low vacuum What are the four types of retort? still steam batch agitating hydrostatic continuous rotory What is the thermal death curve? logarithmic microbial death during thermal processing requires heat and time What is the D-value in terms of the thermal death curve? the amount of time it takes to traverse one logarithmic cycle and kill 90% of microbes ex. D-value of 5 min at 60C means it takes 5 min to kill 90% of microbes at this temperature What is the Z-value in terms of the thermal death curve? # of degrees required to change the D-value by a factor of 10 ex. Z-value of 10 means for every 10 degrees higher the time required to kill 90% of microbes will drop by 10x What is the F-value in terms of the thermal death curve? calculated value of the lethal effect of a process at a specific temperature usually 121C Requirements for reducing the level of microoganisms in a high acid food? need to decrease by 100,000x F-value should be 5x that of the D-value Requirements for reducing the level of microoganisms in a low acid food? need to decrease by 1,000,000,000,000x F-value should be 12x that of the D-value What is still steam retort? common in pet food batch processing, better for conduction heating products, lower efficiency steam retort under high pressure flexibility in container shape/size What is batch agitating retort? containers rotate which may decrease processing time, better for convection heating products batch processing steam retort under high pressure What is hydrostatic retort? continuous/high efficiency low energy consumption constant temperature high investment cost little flexibility in container shape/size What is continuous retort? high efficiency reduced processing time high investment cost little flexibility in container shape/size cans may jam Considerations for creating wet food? nutrition cost palatability appearance packaging format What are functional ingredients in wet food processing? neutraceuticals binders or gums coloring agents What are the main ingredients in wet food? fresh meat water sufficient for processing Most to least expensive: types of wet food formats? Meat-in-jelly or gravy Meat analogs Loaf Pros of wet food? longer shelf life bc sterile palatable digestible increase water intake Cons of wet pet food? expensive potential nutrient loss refrigerate after opening worse for dental health What is baking used for in the pet food industry? mostly used for pet treats few complete and balanced foods What are the physical properties important for baking? dough plasticity dehydration volume change What are the chemical properties important for baking? starch gelatinization protein coagulation What are the biological properties important for baking? yeast gas expansion Final product from baking is determined by which four things? amount of heat rate of heat humidity duration of baking What are the stages of baking? 1. structure development 2. moisture removal 3. color/flavor development What two exchanges are required for baking? heat exchange (conduction, convection, radiation) mass exchange (water removal) What is the most important ingredient for baking? carbohydrates flour for dough