%0 Journal Article 
%A Bermejo Lacida, Ricardo
%A Macías, Manuel
%A Sánchez García, Josefa
%A Love, Robyn
%A Varela Alvarez, Elena
%A Hernández Carrero, Ignacio
%T Influence of irradiance, dissolved nutrients and salinity on the colour and nutritional characteristics of Gracilariopsis longissima (Rhodophyta)
%D 2020
%@ 2211-9264
%U http://hdl.handle.net/10498/34462
%X Colour is immediately perceived by the consumer and crucial for product
attractiveness. In this study, the possibility of obtaining different colour schemes in
the rhodophyte Gracilariopsis longissima using short cultivation protocols (i.e. 9
days) was explored. In a first factorial experiment, the effects of salinity (25‰, 35‰
and 45‰), irradiance (60 and 120 μmol photons m-1 s-1) and nutrient conditions
(N&P enrichment, no enrichment) on the growth, pigment concentration and colour
of G. longissima were assessed. The results indicated that growth rate and
phycocyanin were influenced by the three variables, whereas the concentration of
other pigments (cholophyll a, carotenoids and phycoerytrine) was significantly
influenced by irradiance and nutrient conditions. The colour, defined as the RGB
signal from the photographed thalli, was mainly affected by irradiance and nutrient
conditions. In a second experiment, four culture conditions yielding the most
contrasting colour schemes and growth rates were repeated scaling up the
experiment to get enough biomass and analyze nutritional properties (lipids, fatty
acids, proteins, tissue N and P). The colour schemes and the corresponding culture
conditions selected were: i) dark red; high salinity, low irradiance, nutrient
enrichment; ii) light red; medium salinity, high irradiance, nutrient enrichment; iii)
brownish; low salinity, low irradiance; no enrichment; and iv) green-yellowish; low
salinity, high irradiance, no enrichment. These conditions caused marked
differences in the nutritional properties of the thalli. The light red colour showed the
best nutritional characteristics. Overall, G. longissima was not a suitable source of
omega 3 (maximum lipid content 1.6%; n-6/n-3 >10), but can be a source of Fe
(0.34-0.53 mg g-1 DW) and K (161-103 mg g-1 DW) whereas its K:Na ratio can be
enhanced under increasing salinity. The fast ecophysiological response, and its
wide tolerance to environmental conditions, makes this species and excellent candidate for the development of short cultivation prococols.
%K Gracilariopsis
%K Ogonori
%K Colour
%K Salinity
%K Irradiance
%K Nutrient
%~ Universidad de Cádiz