Kinetic study of the physicochemical and microbiological changes in 'seasoned' olives during the shelf-life period

摘要

The changes that take place during the shelf life of "seasoned" olives (packing conditions: 4% NaCl, 0.1%citric acid, and 0.0175% sorbate) using fresh (FF) and stored (SF) cracked fruits were studied. Texture, L*, b*, NaCl, and pH experienced slight changes. Values of a* and titratable and combined acidity increased following a first-order kinetic with higher constants for FF. Glucose was completely exhausted, and mannitol showed only a slight decline. Hydroxytyrosol and tyrosol contents in brines increased rapidly from the acidic hydrolysis of oleuropein, hydroxytyrosol-4-beta-D-glucoside, and salidroside, the concentrations of which decreased. Sorbate content decreased with time and disappeared completely in SF. Yeasts grew rapidly in FF and were markedly inhibited in SF. There was a moderate growth of lactic acid bacteria in FF, whereas they grew markedly in SF during the first few days. Some of these changes limit the shelf life of the product.