Lupin bitter taste

This is a non-chemical, and probably the first biological, method of determining the presence of alkaloids. It was first used particularly with quinolizidine alkaloids in lupine plants. The tasters were men or animals, even in ancient times. It is based on the fact that quinolizidine alkaloid has a bitter taste. This method is qualitative. Taste is a subjective and individual category, especially in the... 

The quinolizidine alkaloid content of seeds is usually 1-2% (w/w) and is responsible for the characteristic bitter taste of lupin seeds. The development of commercial cultivars of sweet varieties of narrow-leaved lupin Lupinus angustifolius) with quinolizidine alkaloid contents of less than 0.015% (w/w) has expanded the potential use of lupin as a food source (Figure 4.15). However, quinolizidine alkaloids are involved in the defence response in plants, and consequently sweet lupin varieties are less resistant to pathogens and herbivores (Ruiz and Sotelo 2001). 

Lupines have relatively large seeds which contain up to 40-50% protein, up to 20% lipids, and 2-8% alkaloids. To use lupine seed for animal or human nutrition, Homo sapiens, for several thousand years, used to cook the seeds and leach out the alkaloids in running water. This habit has been reported for the Egyptians and Greeks in the Old World, and for the Indians and Incas of the New World. The resulting seeds taste sweet, in contrast to the alkaloid-rich ones which are very bitter. In Mediterranean countries people still process lupines in the old way, and sometimes the... 

Some cultivars belonging to L. albus, L. angustifolius, L. luteus, andL. mutabilis have been selected and bred to produce varieties with low concentration of QAs and, consequently, produce seeds that are less toxic and more palatable. These varieties are also known in literature as low-alkaloid or feed or alkaloid-ftee or sweet lupin, definition that was originally based on their taste. These varieties COTitain low levels of QAs in vegetative parts as well as seed and, not surprisingly, have craisiderably lower resistance to disease and predation compared with bitter, wild germplasm [3]. 

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