Grinding kinetics of red grape seed residue in stirred media mill

- Successful grinding of grape seed was achieved in stirred media mill.
- Effect of tip speed on grape seed grinding was investigated.
- Multimodal size distribution indicated heterogeneous grindability of the layers.
- No structural changes of the ground material was detected.
- Micronization of the grape seed might have the advantage on the extraction process.

The main objective of the present paper was to experimentally investigate the grinding kinetics of red grape seed which is the by-product of winery and juice industry. Stirred media mill was used as a high energy density mill to improve the raw grape seed fineness, i.e. mean particle size approx. 10 µm using various rotor circumferential velocities under dry condition. The effect of stress intensity and stress number on the particle size distribution of ground grape seed was investigated. Optimum conditions (rotor velocity and residence time) were determined, mean particle size close to 10 µm and 5000 cm2/g geometric specific surface area were reached within the studied variables. Additionally, concerning the material structure, FTIR measurements of the ground grape seed samples were carried out which demonstrated that no structural changes were detected. Furthermore, the specific grinding work was measured for each test, in this way energy utilization, efficiency was determined.

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