Some plant food-storage organs, such as potato tubers and onion bulbs, store small amounts of proteins in addition to large amounts of carbohydrates. Seeds, in particular, however, usually contain proportionately larger amounts of proteins in addition to their complement of carbohydrates and are very important sources of nutrition for humans and animals.
One example of an important protein source in human and animal diets is wheat gluten (to which, incidentally, some humans become allergic). The gluten consists of a complex of more than a dozen different proteins. A seed’s proteins get used during germination and its subsequent development into a seedling. Some legume seeds may contain more than 40% protein, but legumes are deficient in certain amino acids (e.g., methionine), and a human diet based on beans needs to be balanced with other storage proteins (e.g., those found in unpolished rice) to furnish a complete complement of essential amino acids. Some seed proteins, such as those of jequirity beans (Abrus precatorius—used in India to induce abortions and as a contraceptive), are highly poisonous.
0 comments:
Post a Comment