Choy sum

Has an earthy taste and means 'heart of the vegetable' in Cantonese.

Alternative Name

Cai xin, Chinese flowering cabbage, Chinese oil vegetable, Chinese silverbeet, choi sum, flowering Chinese cabbage, flowering pak choy, white flowering cabbage, yow choy sum, yu choy

Scientific Name

Brassica rapa var. parachinensis


Choy sum (Chinese flowering cabbage) is characterised by yellow flowers borne on slightly fleshy stems. The oval leaves have slightly serrated margins and can be light or dark green. Unlike many other cabbages, it never forms compact heads and it is more similar to bok choy. This vegetable is a member of the brassica—or cabbage—family, also known as a cruciferous vegetable.

Information for farmers+

Choy sum should have bright green leaves, white flower stems and buds with yellow coloured flowers. It should be tender and fresh with developed but closed buds. Common postharvest defects include flower bud deterioration, leaf dehydration and yellowing, and toughening of stems.

Postharvest storage temperature
Visual quality attributes are best maintained at 0°C for a shelf life of 21 days. Products stored at 5°C maintain marketable quality for 7–14 days.

Controlled atmosphere storage
All the brassica vegetables respond favorably to modified atmospheres. In storage, air circulation should be minimised to limit water loss, excess carbon dioxide should be removed and adequate oxygen levels should be maintained.

Ethylene sensitivity
Exposure to ethylene should be avoided throughout the handling system. It decreases the shelf life of these green vegetables.

Humidity storage
Store at 95-100% relative humidity.

Disease & infection
Various soft rot causing organisms affect shelf life of brassica vegetables. Rots due to these organisms are usually associated with physical injury.

Preparation & Storage+
Keep in vegetable drawer of fridge.
A good source A good source –  1 serve provides 25% of RDI or 4g of fibre A source A source –  1 serve provides 10% of RDI or 2g of fibre
Nutrition information
Qty per serve % RDI per serve Qty per 100g
Energy 53 kJ 1% 71 kJ
Protein 1.0 g 2% 1.3 g
Fat, total 0.2 g 0% 0.3 g
– saturated 0 g 0% 0 g
Carbohydrate 0.7 g 0% 0.9 g
– sugars 0.6 g 1% 0.8 g
Dietary fibre, total 2.1 g 7% 2.8 g
Sodium 10 mg 0% 13 mg
Folate 319 µg 159% RDI 425 µg
Vitamin A (from carotenoids) 173 µg RE 23% RDI 230 µg RE
Vitamin C 35 mg 86% RDI 46 mg
Iron 1.3 mg 11% RDI 1.7 mg
Potassium 255 mg - 340 mg

Note: % RDI are based on an average adult diet of 8700 kJ. Your daily intakes may be higher or lower depending on your energy needs. RDI = Recommended Dietary Intake; ESADDI = Estimated Safe and Adequate Daily Dietary Intake.


Veggy tip

Add choy sum’s crispy, sweet stalks to salads, sandwiches and burgers, or just eat raw. If cooking, steam or stir-fry for maximum health benefits.