LEGUMINOUS SEEDS 159 



water, it should be rejected as a feeding stuff, as 

 mustard seed is present. 



Leguminous Seeds. 



153. Lupine Seeds. 



Lupine seeds, which form a valuable food, contain several 

 poisonous and bitter principles of an alkaloidal nature. These 

 alkaloids are volatile, and may be removed by soaking and boiling 

 the seeds. 



{a) Some lupine seeds are extracted with alcohol 

 in a Soxhlet extractor, the alcohol evaporated off, and 

 the residue taken up by warming with 5 per cent, 

 hydrochloric acid. The extract is filtered, and the acid 

 solution tested for alkaloids with Mayer's reagent and 

 iodine solution (see p. 41). 



{b) The bitter taste of fresh lupine seeds is noted, 

 and 20-30 grams are then soaked in cold or lukewarm 

 water for twenty-four hours, then boiled for an hour, and 

 finally washed well with cold water, the water being 

 changed every two or three hours, or else the washing 

 carried out in a stream of water. The seeds are now 

 dried, weighed, and again tasted, and also tested as in 

 {a) for alkaloidal content. During the process ripe 

 lupine seeds lose 12-20 per cent, of dry matter — mostly 

 nitrogen-free extractive material. Unripe seeds lose up 

 to 30 per cent. 



154. Java Beans, Mauritius Beans, etc. 



These beans, the seed of Phaseolus lunatus, are a nutritious 

 feeding stuff, but unfortunately produce considerable quantities of 

 prussic acid on soaking with water, due to the interaction of an 

 enzyme with a cyanogenetic glucoside (see p. 42). 



(a) Cyanogenetic Glucoside. — Some Java beans are 

 tested for prussic acid as in 149, p. 156. The HCN 

 content may be measured by the processes described 

 under linseed cake (150, 151). 



