University of California

Vegetables English

Asparagus (Green)

Recommendations for Maintaining Postharvest Quality

asparagus064
Trevor Suslow

Department of Plant Sciences, University of California, Davis

Maturity & Quality

Optimum Temperature

0°C-2°C (32°F-35.6°F)

Storage life is typically 14-21 days at 2°C and can be extended up to 31 days by 7-10 days storage at 0°C and atmospheric modification. Extended storage (~10-12 days) in air at 0°C may cause chilling injury.

Optimum Relative Humidity

95-100%

High relative humidity is essential to prevent dessication and loss of glossiness. Drying of the butt-end of spears is a negative quality factor. Commonly asparagus is packed and shipped in cartons with a water-saturated pad to maintain high humidity.

Rates of Respiration

Temp. 
°C (°F)
ml CO2/kg·hr
0 (32) 14-40
5 (41) 28-68
10 (50) 45-152
15 (59) 80-168
20 (68 138-250
25 (77) 250-300

To 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


Responses to Ethylene

Exposure to ethylene will accelerate the lignification (toughening) of asparagus spears in controlled studies. The concentration and duration of exposure to exogenous ethylene, to cause this effect, at commonly encountered levels during storage and distribution are not available.

Responses to Controlled Atmospheres (CA)

Elevated CO2 at 5-10% (typically 7%) in air is beneficial in preventing decay and reducing the rate of toughening of the spears. The beneficial effect is most pronounced if temperatures cannot be maintained below 5°C (41°F). Short (CA) exposure to higher CO2 concentrations (12-20%) is safe and beneficial only if temperatures can be maintained at 0°C-1°C (32°F-33.8°F).

Signs of CO2 injury are small to elongated pits, generally first observed just below the tips. Severe injury results in ribbiness.

Maturity & Quality Photos

asparagus_maturity

Title: Asparagus Maturity

Photo Credit: Marita Cantwell, UC Davis

Temperature & Controlled Atmosphere

Optimum Temperature

0°C-2°C (32°F-35.6°F)

Storage life is typically 14-21 days at 2°C and can be extended up to 31 days by 7-10 days storage at 0°C and atmospheric modification. Extended storage (~10-12 days) in air at 0°C may cause chilling injury.

Optimum Relative Humidity

95-100%

High relative humidity is essential to prevent dessication and loss of glossiness. Drying of the butt-end of spears is a negative quality factor. Commonly asparagus is packed and shipped in cartons with a water-saturated pad to maintain high humidity.

Rates of Respiration

Temp. 
°C (°F)
ml CO2/kg·hr
0 (32) 14-40
5 (41) 28-68
10 (50) 45-152
15 (59) 80-168
20 (68 138-250
25 (77) 250-300

To 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


Responses to Ethylene

Exposure to ethylene will accelerate the lignification (toughening) of asparagus spears in controlled studies. The concentration and duration of exposure to exogenous ethylene, to cause this effect, at commonly encountered levels during storage and distribution are not available.

Responses to Controlled Atmospheres (CA)

Elevated CO2 at 5-10% (typically 7%) in air is beneficial in preventing decay and reducing the rate of toughening of the spears. The beneficial effect is most pronounced if temperatures cannot be maintained below 5°C (41°F). Short (CA) exposure to higher CO2 concentrations (12-20%) is safe and beneficial only if temperatures can be maintained at 0°C-1°C (32°F-33.8°F).

Signs of CO2 injury are small to elongated pits, generally first observed just below the tips. Severe injury results in ribbiness.

Disorders

Physiological and Physical Disorders

  • Asparagus will continue to develop after harvest which is why low temperature postharvest management is critical. Common disorders include upward bending of tips away from gravity and "feathering" (expansion and opening) of tips. Bending will also occur if tips expand to the top of the packaging and are deflected
  • Spear toughening occurs rapidly at temperatures above 10°C (50°F)
  • Bruising and tip-breakage are signs of rough handling and can result in toughening of the spears from wound ethylene
  • Asparagus is sensitive to chilling injury after 10 days at 0°C (32°F). Symptoms of chilling injury include loss of sheen or glossiness and graying of the tips. A limp, wilted appearance may be observed. Severe chilling injury may result in darkening near tips in spots or streaks
  • Freezing injury (water-soaked appearance leading to extreme softening) will likely result at temperatures of -0.6°C (30.9°F) or lower

Pathological Disorders

The most prominent postharvest disease concern is bacterial soft rot, induced by Erwinia carotovora subsp. carotovora. Decay may initiate at the tips or the butt end. Spears that are re-cut above the white portion of the butt end are reported to be most susceptible to bacterial decay.

Special Considerations

Rapid hydrocooling soon after harvest is strongly recommended. Pyramid-shaped wooden or waxed corrugated boxes for hydrocooling combined with center-loading during shipment promote good cooling-air circulation.

Disorders Photos

asparagus_bending

Title: Asparagus Bending

Photo Credit: Leonard Morris, UC Davis 

Asparagus_flower_initiation

Title: Asparagus Flower Initiation

Photo Credit: CDFA 

Asparagus_soft_rot__tip

Title: Bacterial Soft Rot on Asparagus Tips

Photo Credit:  Cantwell, Marita Department of Plant Sciences

asparagus_brokentips

Title: Broken Tips

Photo Credit: CDFA 

asparagus_crooked_spears

Title: Crooked Spears

Photo Credit: CDFA 

asparagus_bacterial_soft_rot

Title: Frozen and Thawed Asparagus

Photo Credit: CDFA 

asparagus_split_spears

Title: Split Spears

Photo Credit: CDFA 

asparagus_wilting

Title: Wilting

Photo Credit: CDFA 

Date

August 1996

Use of Materials

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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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