Study on the tunnel pasteurizer in table olives processing

The application of heat treatment is especially important in maintaining the organoleptic characteristics of fermented agro-food products, which potential consumers perceive as reflecting the quality of these foodstuffs. However, heat treatments can be cause of deterioration of many quality parameters of agro-food products including texture, intended as the consistency of the pulp. Pasteurization is one of the most important steps of the table olives packaging process; it is applied after that olives are properly treated for debittering process. In this study ‘Nocellara del Belice’ table olives produced in 2010 and packaged in glass jars, were subjected to pasteurization at industrial scale using a tunnel pasteurizer with a core temperature of 75 °C for 8 minutes. The aim is to mechanically evaluate the pulp texture evolution that contributes to the quality of the product in a period of time 36 months long from packaging. The experimental tests were performed 6, 12, 18, 24 and 36 months after packing. At each sampling time the consistency of the pulp through compression tests was evaluated. A panel test was also carried out to perform sensory evaluation of these table olives. The results obtained here show that in the period we studied, table olives maintain the requirements regarding physical-mechanical properties, but there is a decrease of some qualitative aspects determining the consumers’ taste and, among these, fruit firmness.