Formulation and Stability of Cellulose-Based Delivery Systems of Raspberry Phenolics

Encapsulation of bioactives is a tool to prepare their suitable delivery systems and ensure their stability. For this purpose, cellulose was selected as carrier of raspberry juice phenolics and freeze-dried cellulose/raspberry encapsulates (C/R_Es) were formulated. Influence of cellulose amount (2.5%, 5%, 7.5% and 10%) and time (15 or 60 min) on the complexation of cellulose and raspberry juice was investigated. Obtained C/R_Es were evaluated for total phenolics, anthocyanins, antioxidant activity, inhibition of alpha-amylase and color. Additionally, encapsulation was confirmed by FTIR. Stability of C/R_Es was examined after 12 months of storage at room temperature. Increasing the amount of cellulose during formulation of C/R_E from 2.5% to 10%, resulted in the decrease of content of total phenolics and anthocyanins. Additionally, encapsulates formulated by 15 min of complexation had a higher amount of investigated compounds. This tendency was retained after storage. The highest antioxidant activities were determined for C/R_E with 2.5% of cellulose and the lowest for those with 10% of cellulose, regardless of the methods used for its evaluation. After storage of 12 months, antioxidant activity slightly increased. Encapsulates with 2.5% of cellulose had the highest and those with 10% of cellulose the lowest capability for inhibition of alpha-amylase. The amount of cellulose also had an impact on color of C/R_Es. Results of this study suggest that cellulose could be a good encapsulation polymer for delivering raspberry bioactives, especially when cellulose was used in lower percentages for formulation of encapsulates.