Efeito do ultrassom nas propriedades reológicas e microbiológicas da pasta de azeitona

Abstract

The olive tree (Olea europaea l.) is one of the most important cultures of the Mediterranean landscape. Olive oil and table olives fermented are the most important products from olive, however in an attempt to take advantage of raw material that visually is not within the standards of quality, emerged the olive paste, which is basically pitted table olives, adding olive oil, lemon juice and spices. The ultrasound is a technology that has proven quite effective in pasteurization processes, extracting, homogenizing among others, and is an interesting technology mainly because it is considered clean, low maintenance cost, enabling satisfactory results as an adjunct of the production of a wide range of products. The main objective of this work was to study the effect of ultrasound on the rheological properties and microbiological characteristics of the olive paste. It was also verified the effect of ultrasound on physicochemical characteristics, pH and water activity of olive pastes. The texture profile analysis, proved that the time of ultrasound has a negative effect on hardness of olive pastes (p<0,05). The remaining parameters are not changed. The values of cohesiveness obtained in the study samples, suggest that the olive pastes have a viscoelastic nature with viscous dominance. The remaining parameters are not changed. The ultrasound showed efficiency in microbiological control of olives pastes, reducing the mesophilic bacteria to values < 102 CFU/g and the yeasts and molds for values of (8,7±2.4).103 CFU/g. On the physicochemical composition it was found that olives pastes treated with ultrasound presented values moisture of 74,69±0,81%, lipid contents of 15,21± 0.21%, protein contents of 1,14±0.05%, and carbohydrates contents of 7,89±0.02%. Overall the results obtained prove that the ultrasound can effectively be an alternative method in the production of olive pastes.