Physicochemical and microbiological assessment of commercial dehydrated black olives

Abstract

Among the many different types of table olives, the production of dehydrated black olives is rather low worldwide, although there is an increasing interest in them from consumers. The physicochemical and microbiological characterization of 20 samples of these olives obtained from different countries and processing methods was studied. The average pH and water activity (a w ) values were 4.7 units and 0.85 respectively, although a great variability was found among samples due to the cultivar and the elaboration method used, including oven-dried olives and dry-salted olives obtained from harvested fruit along with oven-dried fruit from fermented black olives. Moreover, the NaCl concentration in many samples was higher than the unique legal requirement for these olives by international standards (>8–10% in the olive juice), which probably implies a reduction of this mineral in the future as demanded by consumers. More precisely, this product must be valorized based on its 40% content of oil rich in monounsaturated fatty acids, and more than 2500 mg/kg of phenolic compounds and 3500 mg/kg of triterpenic acids which make these olives a very attractive product from a nutritional point of view. • Most of the commercial black olives complied with legal requirements. • NaCl in the olive juice of black dehydrated olives was much higher than established. • They contained more than 2500 mg/kg of phenolic compounds. • They were particularly rich in triterpenic acids (>3500 mg/kg).