Impact of growth conditions on the nitrogen, protein, colour and amino acid profiles of the cultured macroalga, Palmaria palmata
Anthony Temitope Idowu, Miryam Amigo‐Benavent, Marta Santos-Hernández, Susan Whelan, Maeve D. Edwards, Richard J. Fitzgerald
Abstract
Abstract The impact of growth conditions on the nitrogen, protein, colour and amino acid profiles of Palmaria palmata (from 2 locations) were investigated. Laboratory cultures of P. palmata were grown over a period of 18 days with and without nutrient addition, i.e., with culture medium (F/2) and urea (0.05 or 0.10 g L −1 ). The total nitrogen (TN) content of cultured P. palmata originating from longlines harvested from Cork increased with the addition of culture medium (F/2) and urea (0.05 g L −1 ) in comparison to the initial sample (4.15 ± 0.05 vs 1.73 ± 0.03%) while biomass from Galway increased with addition of culture medium (F/2) and urea (0.10 g L −1 ) in comparison to the initial sample (3.72 ± 0.05 vs 2.43 ± 0.06%). The protein nitrogen (PN) and non-protein nitrogen (NPN) of cultured P. palmata originating from Galway also increased when grown with the addition of nutrients. Nutrient enrichment during growth influenced the colour characteristics (lightness L*, redness a*, yellowness b* and colour difference ΔE) and the electrophoretic protein profile. Correlations between TN and ΔE (r = 0.945) for Cork originated sample, PN and ΔE (r =-0.944) and NPN and ΔE (r = 0.734) for Galway originated sample were observed. In-gel digestion followed by UPLC-MS/MS demonstrated that RuBiSCo, phycoerythrin and allophycocyanin expression in P. palmata was enhanced with nutrient addition. Amino acid profile and score analysis showed variation as a function of nutrient addition. Overall, nutrient inclusion in the growth medium provides a strategy for the enhanced production of high-quality protein by P. palmata.