Application of the calorimetric methods to characteristic of seeds from olives.

The management of waste from the food industry is currently of great importance. Making use of alternative wastes is inevitable due to the rapid depletion of natural resources. The olive oil industry represents an important productive sector in the Mediterranean basin countries. Depending on the climate, 15-40 kg of olives can be obtained from one olive tree each year. Olive seed is an essential by-product generated in the olive oil extraction industries and it represents roughly 10% by weight of olive fruit. Olive seeds have characteristics that make them perfect for combustion in a biomass furnace, such as a moisture content of 15% and high calorific value. The seeds of pickled olives are also a significant waste product.

Thermal analysis is convenient and reproducible, and is a useful method for characterizing heterogeneous organic materials. In the present study we have investigated the possibility of use of differential scanning calorimetry for thermal characterization of seeds from green and black pickled olives from Croatia. The differential scanning calorimeter (DSC) with a normal pressure cell equipped with a cooling system was used to determine thermal properties of seeds from olives. The following analyses were also performed: determination of calorific values in a pressure bomb calorimeter, determination of initial water content, determination of changes of water content during drying at the temperatures of 30°C, 50°C and 80°C, determination of a percentage content of seeds mass to the mass of the whole olives, determination of ash content.

Seeds from olives are characterized by very good parameters as a biomass. The analysed olive seeds were characterised by low water content and low ash content and a relatively high caloric value.