Canavalia rosea – Beach Bean (seed)
Canavalia rosea is a vigorous creeper native to coastal areas of Australia from central NSW northwards and around the coast to WA. It is pantropical in distribution. Synonym Canavalia maritima. Halotolerant rhizobia growing in symbiosis with the plant enable it to thrive in low nitrogen and salty environments. The seeds are ejected with great force from the twisted pods as they dry and turn brown.
The first Europeans to eat the cooked beans were Captain Cook and crew at their stay at Endeavour River in North Queensland in 1770. He said they ‘were not to be despised’; Joseph Banks sad they were’ a kind of beans, very bad’. Perhaps he didn’t like beans in general. The raw beans/seeds contain lectins and are poisonous, causing vomiting. Heating and cooking breaks them down. This goes for a lot of wild legumes.
Roasted and pressure-cooked seeds of Canavalia maritima of coastal sand dunes of the southwest coast of India were assessed for proximate and mineral composition, amino acid and fatty acid profiles and anti-nutritional features. Growth and nitrogen balance studies were carried out to assess the nutritive value of thermally treated seeds in the rat. Proteins and energy values of Canavalia seeds surpassed common pulse crops. The carbohydrates and ratio of polyunsaturated-saturated fatty acids of the test seed were superior to soybean. The essential amino acids of treated seeds were higher than the Food and Agriculture Organization (FAO)/ World Health Organization (WHO)/ United Nations University (UNU) pattern recommended for adults. The sulfur amino acid content exceeded that for rice, soybean, and FAO/WHO reference pattern. Phenylalanine (roasted and pressure-cooked seeds) and lysine (roasted seeds) was also higher than the FAO/WHO pattern. The food efficiency ratio, net protein retention, protein retention efficiency, and biological value were significantly different between thermal treatments (P < .05). Pressure-cooked seeds exhibited better biological indices than roasted seeds. Partial detoxification of lectins by thermal treatments in the current study resulted in low protein quality, suggesting that a more appropriate method of processing is needed to eliminate the anti-nutritional factors. This is the first study providing data on the biochemical and protein quality of thermally treated seeds of C. maritima (Nutritional and protein quality evaluation of thermally treated seeds of Canavalia maritima in the rat. Seenaa et al. Nutrition Research Volume 25, Issue 6, June 2005, Pages 587596)
The leaves have been reported to be mildly intoxicating when smoked and for a while were a reported ingredient in the smoking product SPICE.
Care and Cultivation of Canavalia rosea
Canavalia rosea seeds should be slightly nicked away from the embryo (the ‘eye’ of the seed) and soaked in water for a few hours to hasten germination, otherwise just sow 1cm below soil and wait. Sow when conditions are warm; above 20 degrees Celsius during the day. Fast growing ground cover tolerant of dry and salty conditions. A great fast growing ground cover with excellent nitrogen fixing qualities. It will climb up trees if they get in the way but it prefers to grow along the ground.
5 seeds per packet