The biochemical composition of two diatoms after different preservation techniques

Abstract 1. 1. Air- and freeze-drying caused an approximately 70% loss of total lipids, while freezing left unchanged the proximate composition of the two diatoms Chaetoceros sp. and Phaeodactylum tricornutum . 2. 2. Loss of total organics after two months of storage was approximately 20% for air- and freeze-dried algae, but lower (10 and 5% for Phaeodactylum tricornutum and Chaetoceros sp., respectively) in the samples stored in a commercial freezer. 3. 3. The amino acid profiles are similar to those generally reported for algal single-cell protein. Both algae may be considered a good source of dietary protein for aquaculture since they contain all the amino acids considered essential for fish and shrimp, including methionine. 4. 4. Short-chain (14 and 16 C) fatty acids are 90% or more in Chaetoceros , while Phaeodactylum has more than 30% of 18 to 22 C. Unsaturates are approximately 50% for Chaetoceros and vary between 44 and 63% in Phaeodactylum , depending on preservation and storage. 5. 5. Storage caused an increase in the percentages of the essential fatty acids 18:2 and 18:3.