Proceedings of International Congress on Bioactive Compounds and International Workshop on Bioactive Compounds
Proceedings of 2nd International Congress on Bioactive Compounds

Spray drying of grape juice can be a viable alternative to obtain a dried product, which facilitates its handling, storage, and transport, in addition to prolong its shelf life. However, in order for minimize degradation of anthocyanins during processing and storage, it is necessary to choose suitable carrier agents (CA). Proteins have been used as encapsulating material in combination with maltodextrin, since it tends to form fairly dense structures, providing good barrier to oxygen. Due to the current green trend in the market, the use of plant protein can be an alternative to animal protein. Therefore, the objective of this work was to study the potential of application of rice bran protein concentrate (RPC) as CA in combination with maltodextrin (MD) in the microencapsulation of grape juice by spray drying. For this, 5 formulations of feed solutions (FS) with 1.00 g CA/g of soluble solids of the juice were prepared, varying the RPC:MD proportion: 0% (control), 5%, 10%, 15%, and 20%. The feed solutions were dried at 140±2 °C in a laboratory scale spray dryer, using a 1.0 mm diameter two-fluid atomizing nozzle. The outlet air temperature was 79±3 °C. As response, the retention of total anthocyanins in microparticles were obtained by the differential pH method and expressed as a percentage, considering the amount of equivalent milligrams of cyanidin-3-glycoside per kilogram of mass of grape juice, disregarding the CA masses. The control sample, formulated without protein, presented 10.2±1.1% of internal retention and 12.8±3.5% of total retention of anthocyanins, while the sample containing 15% of RPC reached 22.32±1.22% of internal retention and 33.03±2.63% total retention. This result can be explained by the role of the protein in the mechanism of particle formation during spray drying. The RPC may have migrated toward microparticle surface, forming a protective protein layer. Moreover, proteins form less porous structure. These facts can improve the internal and total retention of anthocyanins. No significant difference between samples with 15% and 20% of RPC were observed, with the latter reaching 24.5±1.7% and 40.6±2.7% of internal and total retention, respectively. From an industrial point of view, the use of formulation containing 15% RPC is more advantageous than 20%, as it contains less amount of protein, which is more expensive than MD. Therefore, this study showed that RPC, when used as a carrier agent in combination with MD, increased the internal and total retention of anthocyanins in spray drying of microparticles of grape juice.