Food Processing and Engineering

What are different methods of food preservation?

Food preservation through energy input or temperature reduction (chilling, freezing, blanching, canning, pasteur)Food preservation through water removal (concentration: evap/freeze, frying, food dehydration: hot air, spray, drum, freeze dry, osmotic dehydration)

What are the different categories of food processing technologies?

Food preservation, separation, congregation

What is the agitated think film tubular evaporator, how does it work, what is it used for?

For very viscous foods, feed is spread on the inside of the cylindrical heating surface by wiper blades, small heating area and high cost.

What are the advantages of freeze concentration?

Freeze concentration operating at subzero and is a closed system: No loss of aromas or other volatile components, Retention of all sensory properties of the original feed product, No thermal degradation, Minimized oxidation, No loss of solids, The process is specifically interesting for the treatment of heat sensitive substances and for all applications where maximum retention of a product quality is a key aspect

Name 3 types of driers

Freeze dryer, tray drier, drum dryer

Describe the basic principle of freeze-drying and its advantage over conventional drying.

Freeze-drying (lyophilization) removes water by sublimation under vacuum at low temperatures, preserving flavor, nutrients, and structure better than conventional drying.

What are the stages of freeze drying?

Freezing: Solidifying the water. Primary Drying: Sublimation of ice under vacuum. Secondary Drying: Desorption of bound water.

What are some of the factors that affect the dielectric properties of foods?

frequencies, food composition, moisture content, product temperature, physical state of water in the food, fat content, and product density

The main component of an Infrared Heating Equipment is the radiator, name 3 types of radiators and length of wave.

Gas heated (long waves), electrically heated radiators (tubular/flat metallic heaters (long waves), ceramic heaters (long waves), quartz tube heaters (medium/short waves), and halogen tube heater (ultra short waves))

What are the prefixes for 10^9, 10^12, 10^15, and 10^18?

Giga (10^9), Tera (10^12), Peta (10^15), Exa (10^18)

What is the falling film tubular evaporator, how does it work, what is it used for?

Going with gravity instead of against it, this results in thinner and faster moving film and gives rise to shorter contact time and further improvement in the heat transfer coefficient. The key technical hurdle is the even distribution of liquid to each of the tubes

Name four types of peeling methods.

Hand peeling, flame peeling, mechanical peeling, lye peeling, hot water peeling, steam peeling, abrasion peeling, cryogenic peeling.

What are the effects of drying on flavor?

Heat treatment reduce volatiles, introduces additional compounds, mechanisms (evap, autoxidation fatty acids, thermal decomp, maillard reactions, inactivation volatile forming enzymes) factors: temp moisture content, vapor pressure volatiles, solubility volatiles in water, open pore structure of food)

Name 5 ways that processors can reduce the microbial population or growth of microoragnisms in a food product.

Heat treatment, refrigeration (or decreasing temperature), decrease water activity, removing contaminated portions (or trimming), using chemicals (accept both addivitves and sanitizers, such as chlorine), encouraging the growth of fermentation microorganisms, minimizing contamination, cleaning and sanitization of equipment and facilities, etc.

What are the component of a freeze dryer?

Heating system, refrigeration system, vacuum system, condenser

What are some of the benefits of using a conveyor system in an air impingement oven?

Help cook food well/evenly, control temperature and time, control cooking, cook large amounts of food in a continuous process, shorter process times, improved product quality, can use for both heating and freezing foods

What are the disadvantages of Continuous cryogenic freezing?

High cost of refrigerant. - Cost of pressurized vessel. - Possible quality problems due to cracking.

What are some disadvantages of a scraped surface heat exchanger?

High cost per units area, high operating costs, large floor space requirement vs other heat exchangers, disintegration of fragile particles

What are the limitations of freeze concentration?

High cost, Difficulty in separation of ice from solid, Low upper limit on concentration, Has no effect on enzymes and microbes

Name 5 types of nonthermal pasteurization.

High-pressure processing, pulsed electric field, ultraviolet, radio frequency, ultrafiltration