Leaf protein from azolla: its preparation, quality and utilization in food.
1992
Dela Rosa L.S.
Results revealed that any of the available varieties may be used as leaf protein [LP] source. Leaf crude protein content ranged from 15.026 to 21.795 per cent while percentage recovery of the LP obtained ranged from 0.86 to 1.34 per cent. These results which were not significantly different for the different varieties proved that varietal difference does not affect the choice of azolla as leaf protein source. Subsequent studies on optimizing pH and temperature conditions for LP extraction from azolla showed that the optimum pH was at 4.5 while temperature was at 65 deg C. Leaf protein extracted under these conditions was found to have a crude protein content of 48.02 per cent. The addition of sodium metabisulfite at the rate of 0.25 per cent by weight during extraction slightly increased recovery of LP from 1.07 to 1.20 per cent, and the LP extract was a lighter greenish brown compared to the untreated sample. Amino acids analysis by HPLC showed that azolla LP contained the essential amino acids and was found to be high in lysine (7.53%), although it was quite low in the sulfur-containing amino acids methionine and cyst(e)ine. Beta-carotene analysis revealed that LP contained 5,330.46 IU which was much lower than fresh azolla leaves which had 73,498.37 IU. Fractionation gave prolamin as the major fraction at 2.52% recovery. Its relative molecular weight was 21.9 KD. Protein enrichment studies using the azolla LP showed that it can be used to enrich champorado and cuchinta up to 1.5% while polvoron could be enriched up to 2.5% level, with acceptable sensory qualities.
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