University of California

Fruit English

Banana

Recommendations for Maintaining Postharvest Quality

Banana, Banano (Plátano), Banane

Adel A. Kader

Department of Plant Sciences, University of California, Davis

Maturity & Quality

Maturity Indices

Degree of fullness of the fingers, i.e., disappearance of angularity in a cross section. Bananas are harvested mature-green and ripened upon arrival at destination markets since fruits ripened on the plant often split and have poor texture.

Quality Indices
  • Maturity (the more mature the better the quality when ripe)
  • Finger length (depending on intended use and demand for various sizes)
  • Freedom from defects, such as insect injury, physical damage, scars, and decay
  • As bananas ripen their starch content is converted into sugars (increased sweetness). Other constituents that influence flavor include acids and volatiles

Maturity & Quality Photos

banana_ripening_chart

Title: Banana Ripening Chart

Photo Credit: Don Edwards, UC Davis

banana_maturity_stages

Title: Maturity Stages

Photo Credit: Don Edwards, UC Davis

banana_ripeningvsstarch

Title: Ripening vs. Starch

Photo Credit: Don Edwards, UC Davis

Temperature & Controlled Atmosphere

Optimum Temperature

13-14°C (56-58°F) for storage and transport

15-20°C (59-68°F) for ripening

Optimum Relative Humidity

90-95%

Rates of Respiration Production
Temperature 13°C (56°F) 15°C (59°F) 18°C (65°F) 20°C (68°F)
ml CO2/kg·hr1, 2 10-30 12-40 15-60 20-70

1Low end for mature-green bananas and high end for ripening bananas.

2To calculate heat production multiply ml CO2/kg·hr by 440 to get Btu/ton/day or by 122 to get kcal/metric ton/day.

Rates of Ethylene Production
Temperature 13°C (56°F) 15°C (59°F) 18°C (65°F) 20°C (68°F)
ul C2H4/kg·hr1 0.1-2 0.2-5 0.2-8 0.3-10

1Low end for mature-green bananas and high end for ripening bananas

Responses to Ethylene

Most commercial cultivars of bananas require exposure to 100-150 ppm ethylene 24-48 hours at 15-20°C (59-68°F) and 90-95% relative humidity to induce uniform ripening. Carbon dioxide concentration should be kept below 1% to avoid its effect on delaying ethylene action. Use of a forced-air system in ripening rooms assures more uniform cooling or warming of bananas as needed and more uniform ethylene concentration throughout the ripening room.

Responses to Controlled Atmospheres (CA)
  • Optimum: 2-5% O2 and 2-5% CO2
  • CA delays ripening and reduces respiration and ethylene production rates
  • Postharvest life potential of mature-green bananas: 2-4 weeks in air and 4-6 weeks in CA at 14°C (58°F)
  • Exposure <2% O2 and/or >7% CO2 may cause undesirable texture and flavor
  • Use of CA during transport to delay ripening has facilitated picking bananas at the full mature stage

Temperature & Controlled Atmosphere Photos

banana_respiration

Title: Banana Respiration

Photo Credit: Don Edwards, UC Davis

banana_ethylene_effects

Title: Ethylene Effects

Photo Credit: Don Edwards, UC Davis

Disorders

Physiological and Physical Disorders

Chilling injury. Symptoms include surface discoloration, dull or smokey color, subepidermal tissues reveal dark-brown streaks, failure to ripen, and, in severe cases, flesh browning. Chilling injury results from exposing bananas to temperatures below 13°C (56°F) for a few hours to a few days, depending on cultivar, maturity, and temperature. For example, moderate chilling injury will result from exposing mature-green bananas to one hour at 10°C (50°F), 5 hours at 11.7°C (53°F), 24 hours at 12.2°C (54°F), or 72 hours at 12.8°C (55°F). Chilled fruits are more sensitive to mechanical injury.

Skin abrasions. Abrasions result from skin scuffing against other fruits or surfaces of handling equipment or shipping boxes. When exposed to low (<90%) relative humidity conditions, water loss from scuffed areas is accelerated and their color turns brown to black.

Impact bruising. Dropping of bananas may induce browning of the flesh without damage to the skin.

Pathological Disorders

Crown rot. This disease is caused by one or more of the following fungi: Thielaviopsis paradoxa, Lasiodiplodia theobromae, Colletotrichum musae, Deightoniella torulosa, and Fusarium roseum--which attack the cut surface of the hands. From the rotting hand tissue the fungi grow into the finger neck and with time, down into the fruit.

Anthracnose. Caused by Colletrichum musae, becomes evident as the bananas ripen, especially in wounds and skin splits.

Stem-end rot. Caused by Lasiodiplodia theobromae and/or Thielaviopsis paradoxa, which enter through the cut stem or hand. The invaded flesh becomes soft and water-soaked.

Cigar-end rot. Caused by Verticillium theobromae and/or Trachysphaera fructigena. The rotted portion of the banana finger is dry and tends to adhere to fruits (appears similar to the ash of a cigar).

Control Strategies

Minimizing bruising; prompt cooling to 14°C (58°F); proper sanitation of handling facilities; hot water treatments [such as 5 minutes in 50°C (120°F) water] and/or fungicide (such as Imazalil) treatment to control crown rot.

[For more information, see our publication "Fruit Ripening and Ethylene Management", available for purchase using our Pubilication order form.]

Disorders Photos

banana_anthracnose1

Title: Anthracnose (1)

Photo Credit: Don Edwards, UC Davis

banana_anthracnose2

Title: Anthracnose (2)

Photo Credit: Don Edwards, UC Davis

banana_chillinginjury1

Title: Chilling Injury (1)

Photo Credit: Don Edwards, UC Davis

banana_chillinginjury2

Title: Chilling Injury (2)

Photo Credit: Don Edwards, UC Davis

banana_chillinginjury3

Title: Chilling Injury (3)

Photo Credit: Don Edwards, UC Davis

banana_cigarendrot

Title: Cigar-end Rot

Photo Credit: Don Edwards, UC Davis

banana_crease_stems

Title: Creased Stems

Photo Credit: Don Edwards, UC Davis

banana_crownrot1

Title: Crown Rot (1)

Photo Credit: Don Edwards, UC Davis

banana_crown_rot2

Title: Crown Rot (2)

Photo Credit: Don Edwards, UC Davis

banana_fusarium

Title: Fusarium roseum

Photo Credit: Don Edwards, UC Davis

banana_gray_mold

Title: Gray Mold

Photo Credit: Don Edwards, UC Davis

banana_impact_bruising

Title: Impact Bruising

Photo Credit: Don Edwards, UC Davis

banana_lasiodiplodia

Title: Lasiodiplodia theobromae

Photo Credit: Don Edwards, UC Davis

banana_skin_abrasions

Title: Skin Abrasions

Photo Credit: Don Edwards, UC Davis

banana_thielaviopsis

Title: Thielaviopsis paradoxa

Photo Credit: Don Edwards, UC Davis

banana_verticillium_rot

Title: Verticillium theobromae

Photo Credit: Don Edwards, UC Davis

Date

November 1996

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How to Cite

Author(s) names. Initial publication or update date (located at the top). Title. Link to the specific Produce Fact Sheet webpage (Accessed date)

Example: Cantwell, M. and T. Suslow. 2002. Lettuce, Crisphead: Recommendations for Maintaining Postharvest Quality. 

http://ucanr.edu/sites/Postharvest_Technology_Center_/Commodity_Resources/Fact_Sheets/Datastores/Vegetables_English/?uid=19&ds=799 (Accessed January 18, 2014).

College of Agricultural & Environmental Sciences
Postharvest Technology Center
Department of Plant Sciences

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