Food Processing and Engineering

What types of containers are used in retorts?

Metal cans, glass jars or bottles, flexible pouches, ridged trays

What are three types of food containers commonly used in retorting?

Metal containers (cans), glass containers, retort pouches

List four kinds of food deterioration.

Microbial, insect & rodent, chemical, enzymatic.

What are the types of membranes used in membrane separation?

Microfiltration, ultrafiltration, nanofiltration, reverse osmosis

In the United States, how much chocolate liquor must each of the following products contain? Milk chocolate, sweet chocolate coating, bittersweet chocolate

Milk chocolate: 10%; Sweet chocolate coating: 15%; Bittersweet chocolate: 35%.

Describe the steps in the high-temperature short-time (HTST) pasteurization of milk.

Milk is heated to 72°C (161°F) for 15 seconds → immediately cooled to ≤10°C → held in sterile tanks → packaged aseptically.

What are some of the osmotic agents?

Mono-, di-, polysaccharides, inorganic salts, ethanol, polyols

Give 3 advantages of food dehydration over sun drying.

More controlled conditions, shorter drying time, better sanitary conditions, no climate losses due to weather, some products (such as milk) cannot be sun dried

What are some of the advantages of resistance temperature detectors (also known as RTD)?

Most accurate sensors for industrial applications and have the best long-term stability, can cover a wide range of temperatures, and can hook up to a computer

What are the other food applications for R.O. and U.F.?

Most commercial application is in the dairy industry where it is used to concentrate milk prior to manufacture of dairy products. Other uses include: - The concentration of sucrose and tomato paste. - Separation and concentration of enzymes and other proteins or pectin. - Treatment of water. - Pre-treatment prior to R.O.

Some food products such as salt, dehydrated vegetable and fruit powders, soup and sauce powders and baking powder tend to cake or harden. This can be avoided by anticaking agents. Name two.

Na-, K-, Ca-hexacyanoferrate, Ca-silicate, tricalcium phosphate, Mg-silicate, Mg-carbonate

Give 3 types of natural and 3 synthetic surfactants in foods.

Natural - saponins, lecithin, lipoproteins, gums; synthetic - mono and diglycerides, sorbitan monostearate (SPANs) and polysorbates (TWEENs)

Describe the plot of the sheer force vs viscosity for the following: Newtonian, Pseudoplastic, Thixotrophic

Newtonian: Viscosity remains constant with sheer force; Pseudoplastic: Viscosity decreases with increasing shear stress; Thixotropic: Viscosity decreases over time under constant shear stress

What are 4 advantages of radiant heat?

Non-contact heating, fast response, reduced heating time, uniform heating, reduced quality losses, versatile, simple, compact equipment, and significant energy saving

What are some of the disadvantages of thermal processing?

Nutrient loss, reduce desirable qualities such as texture, flavor, color, lower antioxidant and phenolic content

Name two examples of w/o and o/w emulsions each.

O/w: milk, mayonnaise, salad dressings W/o: Butter, shortenings

Compare ohmic heating and microwave heating in terms of heating mechanism, penetration depth, and limitations.

Ohmic heating generates heat via electrical resistance uniformly throughout conductive food matrices; penetration depends on conductivity. Microwave heating relies on dipole rotation and ionic conduction, with limited penetration depth and risk of non-uniform heating. Ohmic requires conductive foods; microwave suffers from hot spots.

What is the batch pan method, how does it work, what is it used for?

Oldest method of evaporation next to solar evaporation, heating of sample using jacket or internal coils, it has high residence time (many hours). Still used to make jams and jellies

What are some disadvantages of aseptic processing?

Over processing, not easy to ensure the sterility of all equipment used in the process, products that contain particulates processed at high temperatures lose shape and form during the heating and cooling steps

What are two approaches used to make intermediate-moisture foods?

Partial Drying, Osmotic Drying, Dry Infusion, Blending (formulation)