Improvement of the nutritive value of cereals by leaf protein supplementation
1990
Maciejewicz-Rys, J. | Hanczakowski, P.
The gross composition and amino acid content of the proteins of barley, corn, rye, and wheat grains were determined. Leaf protein concentrates (LPC) were produced from the green matter of clover, lucerne, barley and ryegrass using standard methods and analysed as for the cereal grains. Each cereal was mixed with each concentrate at a protein ratio of 2:1, respectively. The chemical score (CS) and essential amino acid index (EAAI) of the cereals, the protein concentrates and their mixtures were calculated. The biological value (BV) and true digestibility (TD) of all proteins were determined on rats using the Thomas-Mitchell balance method. LPC proteins contained more lysine (4.6-60%) but less cystine than cereal proteins (2.8-3.8 and 2.3-2.7 g per 16 g N, respectively). The CS and BV of LPC proteins were low (30-40 and 44-58, respectively) because of the low cystine content. Mixing cereals with LPC improved the CS, EAAI and BV of their proteins. The BV of the protein mixtures was in almost every case higher than that of either protein alone, but the digestibility of the cereal proteins was reduced as a results of admixture with LPC, especially with clover LPC.
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