L5 Processing of Fruits & Vegetables

Lakukan tugas rumah & ujian kamu dengan baik sekarang menggunakan Quizwiz!

Recommended freezing temperature for perishable goods

-30-0

Why are fruit juices harder to dry than proteins or starch based foods?

-At low moisture levels, very hygroscopic, picks up moisture easily. Needs to rapidly packed into hermetically sealed moisture barrier material.

Problems w. refrigeration & freezing F & V

-Chilling injury -dehydration/transpiration

Benefits of continual air circulation in storage room

-Consistent temperature -Minimizes growth of modl

Procedures of harvest to ensure high quality

-Harvest previous to maturity > ripen at maximum rate just before full ripening -cooling fresh produce in the field, canned close to field

Primary precooling methods for fruits and vegetables

-Hydrocooling -Forced-air cooling -Package icing -Vacuum cooling

Pros and Cons of Frozen juices

-Maintains fresh character -costly -deterioration of nutrients, changes in flavor, color, viscosity,

Growing trends in beverages

-Organic ingredients -Without high fructose corn syrup (HFCS)

What do fruits and veggies continue to do during storage

-Respire -Generate heat

Misconceptions about preservatives

-Some are naturally existing -"no preservatives added does not equate to better product"

Processing methods used to preserve fruits and vegetables

-freezing -canning -dehydrating -pickling

Optimum storage temperature of most fruits and vegetables

0.5-1 degrees celsius above freezing point

Temperature swings of __________ from desired temperature must be avoided to maintain high quality and product consistency?

1 degrees celsius above or below

Two major types of operations

1. Canning 2. Freezing

2 processes for juices

1. Good sanitation 2. Low temperature holding

Two methods to manufacture jelly

1. Open kettle 2. Low calorie

Moisture loss can be minimized by

1. keeping storage temperature of food as lwo as possible 2. relative humidity as high as possible 3. avoiding high air velocities

Freezing

3 stages 1. Cooling to the freezing point - removing the sensible heat 2. Freezing - removing the latent heat 3. Further cooling to subfreezing - removes sensible heat of frozen food

Recommended refrigeration temperature for perishable foods

33.8 - 39.2

Standard jelly/jam manufacture requires a minimum of what percentage of weight fruit juice, pump or pieces

45%

Which fruits are commonly cut into smaller cubes/slice prior to freezing

Banana, tomato, mango, kiwi

Which preservatives are added to extend shelf life of minimally processed juice drinks

Benzoates + sorbates

When does enzymatic activity happen?

Between maturity and ripening

Solanine

Bitter, toxic at high levels; seen in onions, potatoesD

Dry pack method for freezing veggies

Blanched & drained vegs > meal-size freezer bags -packed tightly to reduce air -head space (2cm)

CO2 and O2 manipulation are used in what form of control?

CAP - Controlled Atmosphere Packaging MAP - Modified Atmosphere Packaging

What accounts for about 45% of industry revenue?

Canned and frozen foods

What are used to inactivate deteriorate enzymes in fruit

Chemical treatments/additives

Tray Packed Frozen Veggies

Chilled, well-drained veggies in single layer on shallow trays/pans -freezer until firm > removed -filled into containers; remain loose

Precooling

Cooling at the field before the product is shipped to the market or storage warehouse -most important for highly perishable products

Referigeration

Cooling w/o any phase change

Package icing

Crushed ice in containers (fruits)

Low calorie jelly

Difficult to manufacture and store. Susceptible to process contamination and refrigeration after opening

2 Types of packaging for frozen veggies

Dry pack Tray packed

Why does the green color of solanine changes?

Due to chlorophyll degradation > allow carotenoid pigment to be visible (green > yellow > orange >red)

Most common quality defects of fruit wines are

Excessive sweetness Oxidized flavor and color

Blanching

Expose veg. to boiling water/steam for brief period of time to inactivate enzymes -mild heat treatment -mainly for veg.

T or F, most foods freeze at a single temperature

False, range of temperature

T or F, blanching produces a sterile product

False, some microbes are still present; need further treatment to extend shelf life

Astronaut foods are usually

Freeze driedPa

Most expensive dehydration method

Freeze-drying; especially nitrogen gas

Beverages in trend right now

Fruit juices & 100% fruit-puree

What is the simplest fruit dry product?

Fruit leather/fruit rolls; low dextrose added to reduce hygroscopic nature > chewiness ~12% moisture content

Why would freezing fruits be different from freezing veggies?

Fruits are not fibrous -Delicate flavors easily damaged/altered by ehat -best eaten raw -attractive color

What level of maturity are fruits to be frozen at?

Fully ripe & soft in texture

Evidence of ripening

Green chlorophyll pigment - Solanine

Grapes

Harvested after completely ripened; over ripening cause stem detachment and decay; susceptible to moisture loss because of large surface area to volume ratio

Latent heat

Heat required to change form solid to liquid or liquid to gas, at constant temperature

Sensible heat

Heat when added or removed from foods, changes the temperature of foods

Which exceptions don't go through blanching

Herbs Green peppers

Chilling injury

Internal discoloration, soft scald, skin blemishes, soggy breakdown, failure to ripen -severity = temperature + time

Major US based fruits and veggies processing companies

Kraft Heinz JR Simplot Pinnacle Foods ConAgra General Mills

Which type of vegetables are extremely susceptible to presence of ethylene gas?

Lettuce, leafy vegetables

Pears

Loses moisture faster; stored under humid conditions

Transpiration

Loss of moisture from fresh fruits and veggies specifically -causes shrivel/wrinkle/lose quality (sold at lower price) -Varies based on environmental conditions and individual fruits

Does temperature play a role in dry products

Low temperature serves to extend shelf life

Dehydration

Moisture loss

Vinegar fermentation vs. wine making

More difficult to initiate and control

Ethylene Gas & Ripening

Naturally occurring colorless, odorless hydrocarbon in some fruits and vegetables (apples, bananas, citrus fruit, melon, tomatoes) -Generates softening of plant cell wall

T or F, refrigeration, pasteurization, and hermetic packaging increases storage w. minimum quality and changes is still considered fresh

No longer considered fresh

How are freeze-dried juice packaged?

Packaged in pouch of oxygen and moisture impermeable for rehydration. Rehydrated w. water generated from fuel cell reaction of hydrogen adn water

What level of maturity vegetables do manufacturers use for frozen veggies

Peak flavor and texture

Open kettle jelly manufacture

Professional HIgh quality: fruit, sugar, pectin -Immediate hot filling into sanitized jars -Rapid cooling -Low temperature storage

Factors to consider in packaging frozen veg.

Protection from O2 Moisture loss retention of flavor rate of heat transfer

Quality of frozen foods is greatly affected by...

Rate of freezing

Velocity of refrigerated air affects

Rate of moisture loss from products

Effect of evaporation on drying fruit juices

Reduce drying temperature and enhance quality

Climacteric Fruits

Ripen after harvest -Apples -Apricots -Avocado -Banana -Peach -Pear -Plum -Tomato -Papaya -Mango

Non-Climacteric Fruits

Ripen prior to harvest -Cherry -Citrus Fruit -Grapes -Melon -Pineapple -Strawberry

Frozen juices are produced via which processes?

Single strength juice freezing & low oxygen storage

The effects of refrigeration

Slows down chemical and biological processes in food (deterioration & loss of quality & nutrients) -extends shelf life

Benefits of blanching

Slows or stops enzyme action Easier to pack Some bacteria destroyed Surface dirt removed

Ripening can be done through

Sunlight, artificial, or fluorescent light

What process is capable of doing away the need of refrigeration and inactivate enzyme

Thermal processing

Why do fresh fruits and vegetables continue to give off heat even after they are picked?

They are live products

Major processed crops

Tomatoes Potatoes Oranges Corn Cucumbers Beans Grapefruit Apples Grapes Pineapples Peaches

Freshness, crispiness, and water retention in fruits and vegetables are attributed to

Turgor pressor

Turgor Pressure

Vacuoles in cells filled w. water; pressure is exerted on the cytoplasm and partially elastic cell wall

vacuum cooling

Vaporizing water content of products under low pressure conditions

When would headspace be unnecessary when packing freezing vegetables?

Vegetables that don't pack tight to begin with. Ex. broccoli, asparagus, brussel sprouts

Why do fruits and vegetables lose turgor pressure after picked?

Water lost to air w. evaporation or low humidity storage

Are fruits that require peeling peeled previous to freezing?

Yes, by scalding fruit in hot water/steam/hot lye solutions

Most produce can be stored satisfactorily at what temperatures and relative humidity

Zero degrees Celsius and 90-95% relative humidity

Gibberellic acid

control to external storage environment applied preharvest to delay ripening and retain firmness

Forced-air cooling

forcing refrigerated air (flowers)

Hydro-cooling

immersed in to chilled water (w or w/o chlorine)

100% fruit juice-puree mixtures

smoothies w. 100% fruit content


Set pelajaran terkait

Plant Responses to the Environment Test 2

View Set

El Burlador de Sevilla y convidado de piedra

View Set

Chapter 4-Life Policy Provisions and Options

View Set

EMT Chapter 18 Gastrointestinal Emergencies

View Set