Broccoli

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Infobox on Broccoli
Example of Broccoli
Broccoli.jpg
Freshness facts
Optimum carrying temperature 0°C
Highest freezing point -0,6°C
Acceptable product temp. at loading into containers Max. 2°C above carrying temperature
Optimum humidity >95%
Ventilation setting for containers 60 m³/hr
Storage life 2-3 weeks
Climacteric / non-climacteric Non-climacteric
Ethylene production Very low
Ethylene sensitivity High
Modified / controlled atmosphere 1%-2% O2; 5%-10%CO2
Potential benefits Decreased O2 - high; High
Availability
Belgium
Italy
Netherlands
Portugal
Spain
June - November
November - May
May - December
October - May
November - June

Harvesting and Handling

High quality broccoli has either a dark or bright green colour with closed beads, i.e. flower buds. The head should be firm to hand pressure, compact, and the stalk cleanly cut to the appropriate length for a particular grade standard or for crowns. Over-mature heads are characterised by open flower buds or enlarged buds on the verge of opening resulting in a loose head.

The respiration rate of freshly harvested broccoli is very high – comparable to that of asparagus, spinach, or sweet corn. Thus like these crops, broccoli must be cooled immediately after harvest to rapidly lower the respiration rate and be kept at low temperature for maximum shelf life.

The use of perforated plastic film packaging to minimise wilting is also recommended. Rough handling during harvest and packing can damage floret tissue and can lead to increased levels of decays.

Cooling and Storage

Under the recommended storage conditions (0°C and >95% RH), broccoli can be kept in excellent condition for 2 to 3 weeks. Heads stored at 5°C can have a storage life of 14 days; storage life at 10°C is about 5 days. Loss of quality during prolonged storage is a result of wilting, yellowing of buds and leaves, loosening or opening of buds, and decay. High rates of air exchange are recommended in shipping containers to avoid accumulation of off-odours.

Broccoli is extremely sensitive to ethylene, with floret yellowing being the most prevalent symptom. Bead yellowing may occur in over-mature broccoli, when stored at higher than optimal temperatures, and/or in response to exposure to ethylene. Presence of yellow beads ends the commercial marketability of broccoli. There sometimes is confusion between senescence-associated yellow bead and yellow-light green marginal areas of floret that occur due to shading by adjacent floret tissue. This is normal for tissue that is not exposed to light during head growth.

Broccoli is not sensitive to chilling temperatures and should be stored as cold as possible without freezing. When freezing injured, thawed buds will be very dark and translucent, and can later turn brown or may serve as sites for development of bacterial decay.

Controlled atmosphere considerations

Broccoli can be benefited by 1-2% O2 with 5-10% CO2 atmospheres at a temperature range of 0-5°C. Although under controlled conditions such low O2 levels extend shelf-life, temperature fluctuations during commercial handling make this risky as broccoli can easily produce offensive sulphur-containing volatiles. As a result, a high rate of air exchange is recommended in standard marine container shipments of broccoli. Most modified atmosphere packaging for broccoli is designed to maintain both O2 and CO2 at about 10% to avoid the development of these undesirable off-odour volatiles.

Storage disorders

Alternaria rot, Bacterial soft rot, Black rot, Cercosporella, Downy mildew, Grey mould rot, Light leaf spot, Powdery mildew, Mosaic virus, Sclerotium rot.