RP 430 odd

T/F: Desulfotomaculum spp. are anaerobic bacteria that pose a particular threat to spoilage of canned food products.

TRUE

T/F: Periodic interruption of chilling by periods of exposure to warm temperatures has been found to reduce or delay the onset of chill injury in some fruits and vegetables

TRUE

T/F: Black heart in potatoes is often caused by insufficient oxygen, and a rapid shift from aerobic respiration to fermentation.

TRUE

T/F: Water reaches its maximum density at 0 C

FALSE

T/F: Hand filling is often used for high end products especially when a certain visual appearance in a glass jar is desired

TRUE

T/F: When filling a can with fruits or vegetables, the headspace is measured to the nearest 1/4 inch

FALSE

T/F: Unlike most unit operations, minimal processing actually reduces the shelf life of fruits and vegetables and makes them more susceptible to microbial spoilage

TRUE

T/F: The main difference between immersion and cryogenic freezing is that the freelance used in immersion freezing undergo a change of state which is not true for cryogenic freezing

FALSE

T/F: Homogenous nucleation of water in a food is the most common form of crystal initiation

FALSE

T/F: Under the right storage conditions apples can be held for up to a year before being shipped to grocery stores for consumer purchase

TRUE

T/F: As the rate of freezing increases the size of the ice crystal will decrease and the number of ice crystals will increase

TRUE

T/F: Cryogenic freezing is used on products that have a very high value because the process is expensive due to the refrigerants used

TRUE

T/F: A packaging material with a high moisture vapor transmission rate will improve the keeping quality of a frozen food by allowing moisture to rehydrate the surface of the food

FALSE

T/F: Because the density of water is at its maximum of 4 C that will be the temperature at which the water phase of a product will take up the greatest amount of space in the package

FALSE

T/F: Tomatoes are classified as Climacteric Fruits

TRUE

T/F: Oxygen is reduced to 0% in a potato storage facility to ensure that no black spotting will occur on the interior of potatoes headed fora potato chip processing plant

FALSE

T/F: Plants typically have a higher farm value than meats since they can be grown at a much faster rate

FALSE

T/F: Many believe that Nicholas Appert was the grandfather of what we know today as canning when he entered and won a competition in the early 1800s for his innovative approach to extending the shelf life of foods which centered around careful sanitation and sealing

TRUE

T/F: In low acid foods one of the microorganisms of most concern is Clostridium botulinum

TRUE

T/F: Alkaline processing of corn is often used to produce hominy

FALSE

T/F: Alpha, beta, and gluco amylases are often used in the production of high fructose corn syrup

TRUE

T/F: The pH at which a protein has a net charge of zero is most likely to precipitate out of solution is referred to as the isoelectric point

TRUE

T/F: The formation of a strong gel network depends primarily on molecular size

TRUE

T/F: The largest portion of a consumer's dollar pays for the processing of products such as canned green beans

TRUE

T/F: In a non-agitated retort, the cold spot in a can of peas in brine will likely be higher in the can than the cold spot of a food that is made up of one continuous mass

FALSE

T/F: Commercial sterilization of canned food is a 12D process that would reduce an initial population of Clostridium botulinum spores of 1 million down to 1 spore

FALSE

T/F: Canning of low acid foods is regulated by the Food Safety and Inspection Service of the United States Department of Agriculture

FALSE

What are the 4 main stages of fruit development? Which stages of development does ripening typically traverse?

Fruit set

Growth

Maturation

Senescence

Ripening occurs late in growth and development through early senescence

Please write the simple equation for respiration. What is the general purpose of respiration in plants?

C6 (H2O)6 + 6 O2 --> 6 CO2 + 6 H20 + heat

Purpose= capture the chemical energy contained in the glucose C-H bonds

What are the 2 primary types of anaerobic fermentation? Which type of fermentation is most important for manufacture of pickles?

Lactic acid fermentation (Pickles)

Alcoholic fermentation

What are 3 factors that affect respiration in fruits and vegetables?

Temperature

Environmental gases

Product attributes

Physiological state of maturity

What are the 3 classes of respiring products? Give an example of a fruit or vegetable that falls into each category.

Low respiring= longer storage life (i.e. potatoes, carrots)

Intermediate respiring= (i.e. apples, beans, spinach)

High respiring= shorter storage life (i.e. asparagus, peas)

Explain the difference between climacteric and non-climacteric fruits as well as give an example of each. Create a graph illustrating the production of carbon dioxide and ethylene for both climacteric and non-climacteric fruits over time (lifecycle)

Climacteric= sharp increase in respiration rate, even after harvest; sharp increase in ethylene production (i.e. tomatoes, bananas, apples)

Non-Climacteric= continuous decrease in respiration rate (i.e. grapes, oranges, cherries)

Identify 3 factors that influence transpiration in fruits and vegetables.

Maturity

Cuticle waxes

Surface

Injury

Temperature

What are 3 ways to alleviate chill injury in some fruits and vegetables?

Temperature

Atmosphere

Chemical Treatments

Genetic Modification

What are 3 critical control points to keep in mind in most all filling operations?

Control of fill weight

Control of product quality

Control of sanitation

Give 3 examples of fruit and vegetable products which may utilize a positive displacement piston filler.

Soups

Beverages

Pumpkin

Cream style corn

If you are given 5.35 lbs of a pear sauce that has an initial Brix of 10.2, how much sugar do you need to add to have a final sauce that is 14 B? To receive full credit, please show all work

(5.35 + x)(.14) = .5457 + x

x= 0.2364 lbs

What is the difference between sensible and latent heat?

Latent= energy required to undergo a change in state (i.e. water)

Specific= heat needed to change the temperature within a phase

How many BTU of energy must be removed to cool 1 lb of water from 60 F to 0 F? Please keep in mind the specific heat of water is 1 BTU/lb, the specific heat of ice is 0.5 BTU/lb, the heat of fusion is 144 BTU/lb, and the equation Q= mCdeltaT

BTU = (specific heat x temp x weight) + latent heat

Cooling H2O= (1.0 BTU/lb) (60-32)(1 lb)= 28

Fusion= (144 BTU/lb)(1 lb) = 144

Cooling ice= (0.5 BTU/lb)(32-0)(1 lb)= 16

Total BTU= 188

What are the 2 main deleterious effects of ice crystal growth in frozen fruits and vegetables?

Cell concentration causing denaturing of proteins

Damage to plant tissue i.e. cell rupturing

What is freezer burn? Identity 3 factors that influence the rate of freezer burn

Freezer burn is primarily caused by sublimation of ice from surface f product

Fluctuation in temperature and large volumes of air in packaging

Leaks or high moisture vapor transfer rate will cause freezer burn

Explain why it might not be a good idea to macerate apples in a copper pot prior to freezing for long-term storage

Copper acts as a catalyst for enzymes involved in the browning of apples. Must use inert vessels. Presence of iron or copper can increase the rate of the reaction

When choosing a freezing method for a particular fruit or vegetable what are the 2 most important factors that need to be considered?

Cost

Desired end product quality

Explain why one would say that their would be a difference in quality between strawberries that were frozen in a one pound box versus strawberries from the same crop that were frozen using an IQF system.

The strawberries in the one pound box would freeze slowly since it would take time for the core of the box to freeze. This slow freezing would develop large crystals which would result in more damage to the strawberry and in turn a greater drip loss. The IQF has a much faster freezing rate and thus much smaller crystals due to more nucleation sites. This would result in less damage and subsequently less drip loss and overall better quality.

Although both soy beverages and orange juice are plant based liquid foods, the freezing point of orange juice is significantly lower than that of soy beverages. Give a reasonable explanation for this fact

Orange juice is very high in sugar content which is a soluble component which reduces the freezing point. Other reasonable arguments besides sugar content will get partial credit. This is more of a thinking exercise

Give equivalent temperature differentials and airflow during freezing and thawing cycles, which process will take more time? Why?

Thawing takes longer. Heat moves more slowly in water than ice so as the ice builds from outside in, the rate accelerates during freezing. The opposite happens during thawing, where the outer layer that is thawed acts as an insulating layer slowing down heat removal from the product.

Why is it better to freeze a food particle as quickly as possible?

Faster= small ice crystal size

Small ice crystals= less tissue rupture and better texture retention

Why would one have to build separate storage facilities for potatoes and lettuce?

Potatoes have a lower respiration rate and cool slowly

Potatoes can be handled rougher

Lettuce is opposite

Humidity for lettuce must be controlled to prevent excessive transpiration which can lead to wilting

What are 3 characteristics (food trends) that consumers desire when purchasing products in the grocery store?

Greater convenience

Higher quality

More variety and excitement

Design a flow chart for a typical canning operation using the following unit operations as a guide

Product Preparation

Blanch

Fill

Exhaust

Seal

Thermal Processing

Label

Transport

Warehousing

Consumer