Vegetables Produce Facts English

Tomatillo (Husk Tomato)

Recommendations for Maintaining Postharvest Quality

Marita Cantwell

Department of Plant Sciences, University of California, Davis

Publications for this Commodity

Maturity & Quality

Maturity Indices

The tomatillo or husk tomato (Physalis ixocarpa) is a small, spherical and green or green-purple fruit surrounded by an enlarged calyx or "husk." As the fruit matures, it fills the husk and can split it open by harvest. Tomatillos are the key ingredients in fresh and cooked green salsas and other Latin American dishes. The freshness and greenness of the husk is a quality criteria. Fruit should be firm, bright green as the green color and acidic flavor are the main culinary contributions of tomatillos.

Quality Indices

Tomatillos can be harvested at various stages of development. For commercial marketing, they should be harvested when the fruits are well formed and have substantially filled the husk but are still bright green in color. Overmature fruit are light green or yellowing and should be avoided since they are sweeter and undesirable for most uses.

Maturity & Quality Photos

Title: De-husked Tomatillos

Photo Credit: Marita Cantwell, UC Davis

Title: Maturity Stages

Photo Credit: Marita Cantwell, UC Davis

Title: Quality

Photo Credit: Marita Cantwell, UC Davis

Title: Tomatillo with Green Husks

Photo Credit: Marita Cantwell, UC Davis

Temperature & Controlled Atmosphere

Optimum Temperature

Tomatillos can be forced-air or room cooled. The main reason to cool rapidly is to retain the fresh appearance of the husk. Tomatillos can be stored under a wide range of conditions. At ambient temperatures, the husks will dry, but the fruit will remain in good condition for about 1 week. For longer storage life temperatures of 5°C to 10°C (41°F to 50°F) with moderate humidity levels (80-90% RH) are recommended to retain the freshness of the fruit and the husk. At 5°C (41°F) chilling injury will occur after about 3 weeks.

Optimum Relative Humidity

80-90%

Rates of Respiration

Temperature	5°C (41°F)	10°C (50°F)	20°C (68°F)
ml CO₂/kg·hr	6-7	7-10	15-20

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.
Respiration data are for mature fruit. Respiration rates remain relatively constant during storage at 5°C and 10°C; rates decrease during storage at 20°C. Respiration rates of developing fruit are about 25% higher than those of mature fruit.

Rates of Ethylene Production

Tomatillos produce low amounts of ethylene at immature (0.5 to 2 µl/kg·hr at 10 to 20°C [50 to 68°F]) and mature stages (1 to 10 µl/kg·hr ). At horticulturally overmature stages, i.e. when the fruit show yellow color change due to ripening, ethylene production rates can be high (20-40 µl/kg·hr at 20°C (68°F)).

Responses to Ethylene

Exposure of mature fruit to ethylene causes undesirable color change.

Responses to Controlled Atmospheres (CA)

No information is available.

Disorders

Physiological and Physical Disorders

Chilling injury. Tomatillos can be stored at 10°C (50°F) for 1 month without any symptoms of chilling injury. After 3 weeks at 5°C (41°F), the fruit began to show chilling symptoms, and at 2.5°C (36°F), fruit showed significant amounts of chill-induced decay. Typical chilling symptoms include surface pitting and decay.

Pathological Disorders

Chilling injury can result in the appearance of black mold on the fruit due to Alternaria alternata, the same organism found on chill injured tomatoes and peppers. Superficial molds occur on the husk during storage under high humidity conditions, but have not been identified. Washing in chlorinated water reduces superficial mold growth, but may be difficult to implement commercially since it is difficult to remove all moisture from inside the husk.

Disorders Photos

Title: Quality of Fresh and Stored

Photo Credit: Marita Cantwell, UC Davis

Date

August 2000

Use of Materials

The UC Postharvest Technology Center grants users permission to download textual pages (including PDF files) from this World Wide Web site for personal use or to reproduce them for educational purposes, but credit lines and copyright notices within the pages must not be removed or modified.

Except for these specified uses, no part of the textual materials available on the UC Postharvest Technology Center Web site may be copied, downloaded, stored in a retrieval system, further transmitted or otherwise reproduced, stored, disseminated, transferred or used, in any form or by any means, except as permitted herein or with the University of California's prior written agreement. Request permission from UC Postharvest Technology Center. Distribution for commercial purposes is prohibited.

The information in this fact sheet represents our best understanding of the current state of knowledge at the time of the latest update, and does not represent an exhaustive review of all research results. Links to any of these UC Postharvest Technology Center pages are permitted, but no endorsement of the linking site or products mentioned in the linking page is intended or implied by such a link.

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).

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