High hydrostatic pressure treatment of Arthrospira (Spirulina) platensis extracts and the baroprotective effect of sugars on phycobiliproteins

The effect of High Hydrostatic Pressure (HHP) (600 MPa; 300 s) upon phycobiliproteins from Spirulina platensis extract, in aqueous systems, has been investigated along with the potential baroprotective ability of several sugars (sucrose, trehalose and glucose) at different concentrations (20%, 40% w/w). Phycobiliproteins stability and technological functionality were assessed through spectroscopical and colour analysis, and radical scavenging ability. HHP treatment resulted in a decrease of the phycobiliproteins concentration with allophycocyanin being the most sensitive towards HHP stress (p < 0.05). Addition of saccharides had a positive effect on phycocyanin stability with a higher residual concentration after HHP treatment (p < 0.05) irrespective of the type and concentration of sugars added in the system, whilst baroprotective effects on allophycocyanin and phycoerythrin were observed only at the highest (40%) concentrations tested (p < 0.05). After the HHP treatment, colouring ability of Spirulina platensis extract resulted in being directly correlated to phycocyanin concentration variation (R2 = 0.75). Addition of sugars preserved the antioxidant activity of the extract subject to high pressure regardless of the sugar type. Industrial relevance: Spirulina platensis has become a popular ingredient among manufacturers and consumers, especially for its technological functionality and nutritional properties. Nevertheless, processing and storage may result detrimental for its performance in foods. High hydrostatic pressure is a successful, non-thermal technology that is finding increasing applications in the food industry though processing costs of food products stabilized by HHP result, nowadays, being 7 to 15-fold higher than thermal pasteurization. However, consumers today are willing to pay higher prices for higher quality products with better sensory profiles and nutritional properties. Moreover, compared to thermal pasteurization, HHP is a rather new technology whose cost-effectiveness and environmental impact is expected to improve over time, with a consequent reduction of the gap among performance of these two technologies. Hence, this study focused on the effects of HHP treatments on aqueous Spirulina platensis extracts, alone or added with small saccharides to evaluate their potential baroprotective abilities, providing results of interest for application in food product design and development.