| 摘要 |
Chlorophyll-containing algae are rendered suitable for human consumption by exposing the algae, in the absence of carbon dioxide, to an intense white light until substantial bleaching of the algae has been effected. In a preferred embodiment for preparing an algae nutriment, a concentrated culture of unicellular chlorophyll-containing algae is aged for from 72 to 96 hours in a liquid medium, after aging the pH of the culture is adjusted to 8.0-8.5, gaseous oxygen free of carbon dioxide is mixed with the culture and then bleaching is effected by exposing the culture whilst agitated by stirring or the admission of the gaseous oxygen or aeration devoid of carbon dioxide, to white light of intensity in excess of 2000 foot candles for between 2 and 24 hours duration. The bleached algae are separated from the suspension by centrifugation and freeze-dried to give a fluffy white or light tan powder of bland flavour and odour which may be used directly as a food or food supplement. The value as nutriment of algae of the variety Chlorella pyrenoidosa is discussed; it is stated that when a culture of this variety is grown in the presence of thiourea at a level approximately 10 per cent of the routinely used nitrogen source, urea, sufficient sulphur amino acids for daily consumption are provided by about 200 grams of the dry cell mass. |
