6.2 chemicals used in fruit ripening 🧪

Question 1

▪ “ripening hormone” of plants

Answer 1

Ethylene Gas

Question 2

▪ responsible for variety of processes such as:
✔ rise in respiration
✔ autocatalytic ethylene production
✔ changes in color, texture, aroma and flavor

Answer 2

Ethylene Gas

Question 3

▪ used in agriculture to force ripening of fruit

Answer 3

Ethylene Gas

Question 4

▪ threshold level for _________ in most fruits is 0.2-1.00 ppm

Answer 4

ethylene

Question 5

▪refers to the ethylene inside the fruit that can increase the autocatalytic production of ethylene

Answer 5

threshold level

Question 6

▪ ethylene from outside source has to be applied a hundredfold or more to attain the threshold level of ethylene inside the _______ of the fruits

Answer 6

tissue

Question 7

▪ recommended _________ varies on the method of application, commodity, and cultivar

Answer 7

concentration

Question 8

▪ ethylene must be applied at the _________ possible level and at the _________ possible time to prevent the growth of microorganisms that are stimulated by ethylene (i.e., Diplodia stem end rot)

Answer 8

lowest; shortest

Question 9

▪ the greener and younger the fruit, the ________ is the degreening or ripening period

Answer 9

longer

Question 10

▪ ethylene can be ________ when handled improperly

Answer 10

explosive

Question 11

▪ __________ at 30,000 ppm or 3%

Answer 11

explosive

Question 12

▪ effective degreening concentrations range from ___________

Answer 12

100 to 1000 ppm

Question 13

▪ ethylene is added every 6-8 hours periodically

Answer 13

Shot or Intermittent Method

Question 14

▪ the room is ventilated every time the room is recharged with ethylene in order to keep CO2 down

Answer 14

Shot or Intermittent Method

Question 15

▪ __________ – 100-1000 ppm for 24 hours at 14-20°C

Answer 15

bananas

Question 16

▪ _________ & ___________ – 100 ppm

Answer 16

mangoes & avocados

Question 17

▪ _________ – 250-500 ppm

Answer 17

pummelos

Question 18

▪ __________ – 1000 ppm

Answer 18

pineapple

Question 19

▪ ethylene is continuously added to the circulating air at 20-30 ppm for 24-48 hours
▪ commonly done by bubbling it through a special metering device
▪ fan circulates the ethylene together with a small flow of air drawn into the room by an adjustable intake

Answer 19

Trickle System with Continuous Ventilation

Question 20

▪cheaper set-up
▪more amt of ethylene used
▪more losses from mold and shrinkage
▪not constant or slower rate of ripening or degreening

Answer 20

Shot Method

Question 21

▪expensive set-up
▪less amt of ethylene used
▪less losses from mold and shrinkage
▪ constant or faster rate of ripening or degreening

Answer 21

Trickle Method

Question 22

▪ ethylene is supplied continuously at 25°C for 12 hours followed by a 12-hour interruption
▪ a continuous low ventilation rate and high humidity is provided

Answer 22

Modified Intermittent Method

Question 23

▪ a liquid which is proprietary product produces ethylene when heated in the presence of catalyst

Answer 23

Ethylene Generators

Question 24

▪ a method used in Japan by filling rubber balloons with ethylene and tied securely at the neck

Answer 24

Use of Rubber Balloons

Question 25

▪ _________ from Small Pressurized Canisters

Answer 25

Ethylene

Question 26

▪ ethylene absorbed in a substance called molecular sieve that gives up ethylene when exposed to moisture

Answer 26

Ethylene Sieves

Question 27

▪ developed by Kitagawa of Japan

Answer 27

Polyethylene Tent

Question 28

▪ a tough, light, and flexible resin made for polymerizing ethylene ▪ mainly use for packaging purposes

Answer 28

polyethylene

Question 29

1.) Fruits are stacked on a rectangular block on a sheet of ______________ (0.2 mm thickness) surrounded by a wooden container.

Answer 29

polyvinylchloride

Question 30

2.) Fruits are covered with a second sheet of ________.

Answer 30

film

Question 31

3.) The underlying and covering sheets of films are then sealed by filling the trough with ___________

Answer 31

water

Question 32

4.) The fruits are then uncovered after _____ hours and allowed at ________ temperature.

Answer 32

15; ambient

Question 33

5.) If the color of the fruit has not completely developed after ____ days, it will be treated again

Answer 33

3

Question 34

▪ plant growth regulator ▪ regulates phases of plant growth and development by application to various growth sites ▪ an expensive method for small farmers and traders, but less expensive than ethylene gas

Answer 34

Ethephon

Question 35

▪ chemically known as chloroethyl phosphonic acid

Answer 35

Ethephon

Question 37

▪ sold as Ethrel that contains 4 lbs/gal or 480 g/L of ethephon as active ingredient

Answer 37

Ethephon

Question 38

▪ currently registered in the US for use on apples, barley, blackberries, bromeliads, cantaloupes, cherries, and coffee

Answer 38

Ethephon

Question 39

▪ Ethrel formulation is adjusted to pH 1 ▪ very stable below pH 4

Answer 39

Ethephon

Question 40

▪ easily decomposes and ethylene is liberated at pH 4.6 ▪ plant cells normally have a pH of 5 so when exposed to ethephon, ethylene is liberated

Answer 40

Ethephon Action

Question 41

▪added to ethephon and liberate ethylene

Answer 41

sodium hydroxide

Question 42

▪ ______ ppm for Latundan and Lakatan banana ▪ ______ ppm for Morado banana, Cavite papaya, Ladu mandarin, Valencia orange, 2029 tomato ▪ _____ ppm for mango

Answer 42

2,500-5,000; 5,000; 1,000

Question 43

▪ dipping fruits for 5 minutes; air dry and pack or ripen first before packaging; dip for 30 seconds

Answer 43

Ethephon dipping

Question 44

▪ _______ spray to run off; not practical for tomato as the stem scar is the only avenue for the passage of gas

Answer 44

Ethephon Spraying

Question 45

▪evolution of ethylene from Ethrel; slower effect than dipping and spraying; do not release residues compared to other methods

Answer 45

Use of sodium hydroxide

Question 46

▪ activity is 100 times less than that of ethylene so it is less effective

Answer 46

Acetylene Gas

Question 47

▪ Acetylene Gas is explosive at _____ volume of ethylene per volume air

Answer 47

2.5-8%

Question 48

_____ ppm concentration Acetylene Gas for Mango ‘Kaeui’

Answer 48

6,000

Question 49

_____ ppm concentration Acetylene Gas for Banana

Answer 49

2,000-10,000 at 20°C

Question 50

_____ ppm concentration Acetylene Gas for Chico

Answer 50

16,000 ppm at 23-28°C at 70-90% RH at 2-3 days

Question 51

▪ a cheap and a readily available source of acetylene in rural areas sold in the form of irregular-sized chunks

Answer 51

Calcium Carbide

Question 52

▪ used for lighting and as a substitute for white paint ▪ widely used in ASEAN countries, Bangladesh, Pakistan, China, India, Burma, and Sri Lanka ▪ used for bananas, mangoes, chico, papaya, and tomatoes

Answer 52

Calcium Carbide

Question 53

Small chunks of fruits are wrapped and planted at the ________ of the container or among the fruits

Answer 53

bottom, middle

Question 54

Fruits with Calcium Carbideis then sealed lightly and opened after _____ days depending on the commodity.

Answer 54

1-3

Question 55

▪ _______ of fruits must be porous to allow diffusion of gases ▪ banana leaf sheath, banana leaf, newspaper, or cloth

Answer 55

wrappers

Question 56

▪ suggested _________ for treatment: boxes, drums, earthen jars, or baskets

Answer 56

containers