Fine beans, French beans, haricot vert, snap bean, string bean, wax bean
Green or French beans are found in two major groups: bush beans and pole beans. Although the pole type and runner beans have similar habits they are actually different varieties. Green beans have a long, thin, green, crisp pods with small, round, smooth seeds inside. The pods are usually tender and the complete pod is eaten after trimming the ends.
Beans should be harvested when the fruit is bright green, the pod is fleshy, and seeds are small and green. Beans should be well formed and straight, bright in colour with a fresh appearance, and tender but firm. They should snap easily when bent. Decreased quality during postharvest handling is most often associated with water loss, chilling injury and decay.
Postharvest storage temperature
Optimum storage is 5–7.5°C. Lower temperatures result in chilling injury—opaque discolouration, pitting on the surface and rusty brown spots. Higher temperatures result in faster deterioration. Beans stored at >10°C lose chlorophyll, soften and shrivel more so than those stored at <10°C.
Controlled atmosphere storage
At recommended storage temperature, O2 concentrations of 2–5% reduce respiration rates. Beans tolerate and are benefited by CO2 concentrations between 3–10%. Higher CO2 concentrations can cause off-flavors.
Exposure to ethylene causes loss of green pigment and increased browning. Concentrations above 0.1ppm reduce green bean shelf-life by 30–50% at 5°C.
Packaging creates a high relative humidity and reduces water loss to maintain better overall quality. The rate of water loss of immature beans is higher than for mature beans and varies with cultivar.
Disease & infection
Various pathogen decay occurs after beans have been damaged. Surface decay may also occur if free moisture is present in storage at >7.5°C.
Serve with a squeeze of lemon and black pepper. Alternatively, sprinkle with chopped red chillies and coriander.