8.2.3 Microalgae for Human Consumption
It was not until the 1950s that microalgal biotechnology began to emerge as a viable
technology; since then it has had numerous successful commercial applications as
mentioned above. Microalgal products are now used to enhance the nutritional
value of human food owing to their chemical composition. However, microalgae to
date are still not a major food group replacement. This is mostly due to its green
color and fishy smell of the microalgae powder. Nowadays, more effort is placed in
searching for new ways for using microalgae in prepared foods like bread, soup,
noodles, and more, in order to gain public interest and acceptance for human use.
Feeding microalgae to humans as a major dietary item has been a virtually
unexplored field of investigation. However, there have been limited studies carried
out in the past with prisoners. Taste experiments have been conducted where they
found that consumers accept green algae powder in their food when it was hidden
in already green foods like spinach noodles and mint ice cream (Morimura and
Tamiya 1954). Earlier workers (Hayami and Shino 1958) have reported the ‘‘true
digestibility’’ of decolorized Chlorella to be 83.0 %. They also reported that the
residual smell and taste of the decolorized Chlorella were intolerable and that it
impaired appetite (Hayami et al. 1961). In later studies, ‘‘true digestibilities’’ of
75 % for blanched microalgae and 86 % for methanol extracted microalgae were
reported. In these two studies, approximately 30 g of microalgae were fed per day.
This supplied about one-third of the total protein. Only one study (Powell et al.
1961) reports feeding amounts of microalgae in excess of 35 g (dry weight) per
day. Subjects tolerated amounts of up to 100 g/day quite well, but acute toxicity
symptoms developed at 200 and 500 g levels.
8.2.4 Microalgae for Animal Consumption
Microalgae can be used to enhance the nutritional value of animal feed, due to
their well-balanced chemical composition. In addition, microalgae can be incorporated into the feed for a wide variety of animals ranging from fish (aquaculture)
to pets and farm animals (Spolaore et al. 2006). In fact, 30 % of the current world
algal production is sold as animal feed applications (Becker 2004). Microalgae are
utilized in aquaculture as live feeds for all growth stages of bivalve molluscs,
juvenile fish, crustaceans, and for zooplankton used in aquaculture food chains.
Several microalgae species have been tested as feed, but probably less than 20
have gained widespread use in aquaculture. Microalgae as feed source must
possess a number of key attributes to be useful, mainly: (1) an appropriate size for
ingestion, (2) readily digestible, (3) rapid growth rates, (4) high tolerance to
environmental conditions, and (5) good quality as a nutrient (no toxins).
The survival, growth, development, productivity, and fertility of animals are a
reflection of their health. Feed quality is the most important exogenous factor
262
M. Vanthoor-Koopmans et al.
It was not until the 1950s that microalgal biotechnology began to emerge as a viable
technology; since then it has had numerous successful commercial applications as
mentioned above. Microalgal products are now used to enhance the nutritional
value of human food owing to their chemical composition. However, microalgae to
date are still not a major food group replacement. This is mostly due to its green
color and fishy smell of the microalgae powder. Nowadays, more effort is placed in
searching for new ways for using microalgae in prepared foods like bread, soup,
noodles, and more, in order to gain public interest and acceptance for human use.
Feeding microalgae to humans as a major dietary item has been a virtually
unexplored field of investigation. However, there have been limited studies carried
out in the past with prisoners. Taste experiments have been conducted where they
found that consumers accept green algae powder in their food when it was hidden
in already green foods like spinach noodles and mint ice cream (Morimura and
Tamiya 1954). Earlier workers (Hayami and Shino 1958) have reported the ‘‘true
digestibility’’ of decolorized Chlorella to be 83.0 %. They also reported that the
residual smell and taste of the decolorized Chlorella were intolerable and that it
impaired appetite (Hayami et al. 1961). In later studies, ‘‘true digestibilities’’ of
75 % for blanched microalgae and 86 % for methanol extracted microalgae were
reported. In these two studies, approximately 30 g of microalgae were fed per day.
This supplied about one-third of the total protein. Only one study (Powell et al.
1961) reports feeding amounts of microalgae in excess of 35 g (dry weight) per
day. Subjects tolerated amounts of up to 100 g/day quite well, but acute toxicity
symptoms developed at 200 and 500 g levels.
8.2.4 Microalgae for Animal Consumption
Microalgae can be used to enhance the nutritional value of animal feed, due to
their well-balanced chemical composition. In addition, microalgae can be incorporated into the feed for a wide variety of animals ranging from fish (aquaculture)
to pets and farm animals (Spolaore et al. 2006). In fact, 30 % of the current world
algal production is sold as animal feed applications (Becker 2004). Microalgae are
utilized in aquaculture as live feeds for all growth stages of bivalve molluscs,
juvenile fish, crustaceans, and for zooplankton used in aquaculture food chains.
Several microalgae species have been tested as feed, but probably less than 20
have gained widespread use in aquaculture. Microalgae as feed source must
possess a number of key attributes to be useful, mainly: (1) an appropriate size for
ingestion, (2) readily digestible, (3) rapid growth rates, (4) high tolerance to
environmental conditions, and (5) good quality as a nutrient (no toxins).
The survival, growth, development, productivity, and fertility of animals are a
reflection of their health. Feed quality is the most important exogenous factor
262
M. Vanthoor-Koopmans et al.