Kinetic modelling of ultrasound-assisted extraction of phenolics from cereal brans

Cereal brans are by-products of the milling of cereal grains, which are mainly used as low value ingredients in animal feed. Wheat and oat bran is a rich source of bioactives and phytochemicals, especially phenolic compounds. Within this study, the application of ultrasound (US) technology to assist the extraction of phenolics from oat and wheat bran was investigated (20-45 kHz). Peleg's mathematical model was used to study the kinetics of ultrasound-assisted extraction (UAE) and subsequent stirring of total phenolic compounds (TPC). The surface morphology of cereal brans after extraction was studied using SEM analysis. The excellent agreement was determined between the values of TPC calculated from Peleg's mathematical model and actual experimental results. The constant that represents a time required for the initial phenolic concentration to be extracted to onehalf of its initial value has been introduced (K1/2). It was shown that the TPC extraction kinetics was dependent only on K1/2 enabling fast kinetics fitting and comparison between extraction rates. Moreover, different values of K1/2 constant could indicate the differences in brans composition and consequently different influence of US pretreatment on these samples.

Automated summary

This study investigated the extraction of phenolics from wheat and oat bran using ultrasound technology. The kinetics of ultrasound-assisted extraction and subsequent stirring of total phenolic compounds were analyzed using Peleg's mathematical model. SEM analysis was used to study the surface morphology of cereal brans after extraction. The results showed that the TPC extraction kinetics was dependent on the K1/2 constant, indicating differences in bran composition and the influence of US pretreatment on the samples.