Page 297 - Algae

280 Algae: Anatomy, Biochemistry, and Biotechnology

does not dissolve is removed by filtration; others are suspensions of very fine particles of
macroalgae.
Macroalgae extracts have given positive results in many applications. There are probably other
applications where they have not made significant improvements, but these receive less, if any, pub-
licity. However, there is no doubt that macroalgae extracts are now widely accepted in the horticul-
tural industry. When applied to fruit, vegetable, and flower crops, some improvements have
included higher yields, increased uptake of soil nutrients, increased resistance to some pests
such as red spider mite and aphids, improved seed germination, and more resistance to frost.
There have been many controlled studies to show the value of using macroalgae extracts, with
mixed results. For example, they may improve the yield of one cultivar of potato but not another
grown under the same conditions. No one is really sure about why they are effective, despite
many studies having being made. The trace element content is insufficient to account for the
improved yields, etc. It has been shown that most of the extracts contain several types of plant
growth regulators such as cytokinins, auxins, and betaines, but even here there is no clear evidence
that these alone are responsible for the improvements. Finally there is the question, are macroalgae
extracts an economically attractive alternative to NPK fertilizers? Perhaps not when used on their
own, but when used with NPK fertilizers they improve the effectiveness of the fertilizers, so less
can be used, with a lowering of costs. Then there are always those who prefer an “organic” or
“natural” fertilizer, especially in horticulture, so macroalgae extracts probably have a bright future.

COSMETICS
Extract of algae is often found on the list of ingredients on cosmetic packages, particularly in face,
hand, and body creams or lotions, but the use of algae themselves in cosmetics, rather than extracts
of them, is rather limited.
Milled macroalgae, packed in sachets, is sold as an additive to bath water, sometimes with
essential oils added. Bath salts with macroalgae meal are also sold. Thalassotherapy has come
into fashion in recent years, especially in France. In thalassotherapy, macroalgae pastes, made
by cold-grinding or freeze-crushing, are applied to the person’s body and then warmed under infra-
red radiation. This treatment, in conjunction with seawater hydrotherapy, is said to provide relief
for rheumatism and osteoporosis. Mineral-rich seawater is used in a range of therapies, including
hydrotherapy, massage, and a variety of marine mud and algae treatments. One of the treatments is
to cover a person’s body with a paste of fine particles of macroalgae, sometimes wrap them in cling
wrap, and warm the body with infrared lamps. It is said to be useful in various ways, including relief
of rheumatic pain or the removal of cellulite. Paste mixtures are also used in massage creams, with
promises to rapidly restore elasticity and suppleness to the skin. The macroalgae pastes are made by
freeze grinding or crushing. The macroalgae is washed, cleaned, and then frozen in slabs. The slabs
are either pressed against a grinding wheel or crushed, sometimes with additional freezing with
liquid nitrogen that makes the frozen material more brittle and easier to grind or crush. The
result is a fine green paste of macroalgae.
There appears to be no shortage of products with ingredients and claims linked to macroalgae:
creams, face masks, shampoos, body gels, bath salts, and even a do-it-yourself body wrap kit. The
efficacy of these products must be judged by the user. A company recently pointed out that the life-
time of cosmetic products has reduced over the years and now rarely exceeds 3 or 4 years. Perhaps
the macroalgae products that are really effective will live longer than this.
Cosmetic products, such as creams and lotions, sometimes show on their labels that the contents
include “marine extract,” “extract of alga,” “macroalgae extract” or similar. This usually means that
one of the hydrocolloids extracted from macroalgae has been added. Alginate or carrageenan could
improve the skin moisture retention properties of the product.