Radish

MATURITY & QUALITY

Maturity Indices

Radish (Raphanus sativus L.) is a diversely formed root vegetable and has many uses worldwide. Red and icicle radish are most common but Asian “daikon” types are increasing in popularity outside of countries such as Korea, Japan, Taiwan and China. The number of days post-seeding or emergence, which may vary from 30 to 70 days, depending on type, typically determines maturity. A minimum size standard for common red radish is 5/8 inch (1.6cm) equatorial diameter. Current crop management practices stress rapid growth to ensure a mild flavor and crisp texture. Fertilization and irrigation management, or environmental conditions that slow growth may result in a woody texture and high pungency. Over-mature radish tends to be pithy (vacuolated) or spongy in texture and may develop harsh flavors, for most palates.

Quality Indices

Roots of Bunched or Topped Common Red Radish should, ideally, be of uniform and similar shape for the variety, well formed, smooth, firm but of tender texture, and free of growth or harvest damage, and free of decay, disease or insects. Bunched radish tops should be fresh in appearance, turgid, and free of freeze injury or other serious injury, seed stalk, yellowing or other discoloration, disease, decay, or insects

U.S. Grade Standards effective October 1968 includes U.S. No. 1 and Commercial

TEMPERATURE & CONTROLLED ATMOSPHERE (CA)

Optimum Temperature

32°F (0°C). Rapid cooling is essential to achieve the full storage potential of both bunched and topped roots. Radish is often top-iced to maintain temperature and contribute moisture for retaining a crisp texture. Under these conditions common red radish may be expected to maintain acceptable quality for 7 to 14 days with tops and 21 to 28 days if topped. Daikon-type radish may last from 3 to 4 months at these same conditions.

Optimum Relative Humidity

95 – 100%

Rates of Respiration 

Common Red Radish:

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

Very low; <0.1 mL/kg·hr at 20°C

Responses to Ethylene

Not Sensitive. Bunched tops may exhibit yellowing with prolonged storage and ethylene exposure.

Responses to Controlled Atmospheres(CA)

Atmospheres of 1 to 2% O₂ and 2 to 3 % CO₂ are slightly beneficial in maintaining quality of topped radish when storage temperatures are 5 to 7°C (41 to 45°F). CA helps retard the re-growth of shoots and rootlets in “topped and tailed” roots. Even short exposure to temperatures above 7°C (45°F) will result in the development of off-flavors, browning, and soft-rot.