Effects on the quality properties of using nannochlorpsis oculata microalgae biomass in white chocolate and white spread cream compositions

The use of biaoctive compounds and natural pigment sources in chocolate technology and the high color stability of the product as a result of this use are important for consumer expectations and safety as well as industrial applications. In this study, the effects of the use of Nannochloropsis oculata microalgae, which is grown by using tubular photobioreactor technique as chlorophyll-a source, on white chocolate and white spread composition after the encapsulation or drying by using spray dryer technique, and its effect on color stability as well as the main quality characteristics were investigated. For this aim, both forms of microalgae source (dried and encapsulated) (0; 0.125; 0.250; 0.500 and 0.750 g/100g) were used. The colour properties [L *, a *, b *, C * (chroma), h(hue angle), WI (whiteness index] and colour stability (delta-E) under accelerated shelf life conditions (25°C/70% RH) of samples were determined for 5 and 6 weeks. The delta-E value for all sample groups was determined to be below the limit value of 3.0 for visible color change and difference. Therefore, the use of both forms of N. oculataas as a stable bioactive compound and pigment source been investigated. White chocolate and white spread samples used in microalgae showed no significant change in water activity (aw), humidity, instrumental hardness, yield stress, plastic viscosity, consistency, flow behavior index and some of the melting properties (P<0.05), whereas the other quality paraemeters were determined in acceptable levels. The chlorophyll-a contents of the white chocolate and white spread samples were determined as 9.60-22.9 µg/g and 60.0-315.7 µg/g respectively. Results of the study indicated the significant advantage for the pigment stability of the encapsulation and spread process conditions. It was determined that the process and matrix improved the chlorophyll-a stability. It was found that the sensory properties of the samples were not affected by appearance, texture, melting in mouth and odor with significant microalgae use (P<0.05). However, it was noteworthy that there was a decrease in taste and general appreciation and a lower intensity in the use of encapsulated microalgae (P<0.05). As a result, it has been determined that the spray drying technique is a feasible technique for drying microalgae. However, it is possible for the encapsulation application to provide advantages in terms of pigment level, color stability and sensory properties. For this aim, it may be possible to obtain more advantageous products in terms of quality characteristics with the studies to be carried out to optimize the encapsulation conditions with spray-drying process conditions. In addition, according to results of this study, it can be stated that the use of microalgae may be found in order to enrich the chocolate and derivative products by the bioactive components and this possibility should be confirmed by further studies. Keyword: Chocolate, Colorant, Microalg, Nannochloropsis oculata, Spray Dryer