Prolongation of table olive shelf-life by combining edible coating application and modified atmosphere packaging (MAP)

摘要

Olives (olea europaea) are of the oldest cultivated fruits, largely found in the Mediterranean countries. Afterfermentation they are usually stored in brine in plastic or glass containers and in cans. The aim of this studyis to introduce a new type of preservation and packaging of table olives which can maintain their qualitycharacteristics by using combinations of edible coatings application and modified atmosphere packaging(MAP). Green and brown table olives preserved in brine were treated with aqueous solutions 1% of hydroxypropyl-methyl-cellulose (HPMC) and chitosan, then packed in normal or modified atmospheres (100% N_2,80% CO_2 - 20% Air) and stored at ambient temperature (25°C). During storage the olives were examined fortheir colour, texture (firmness), weight loss, pH, titratable acidity (expressed as lactic acid/100mg of olivepulp) and were assessed for their sensory characteristics. The shelf life of the coated packaged olives wasalso estimated.The coating resulted in reducing of weight loss, maintenance of colour and firmness and extension of shelflife of the olives. Comparing the two coatings, chitosan in most cases proved more efficient than HPMC inolive preservation. As for the packaging atmosphere, good preservative results were obtained for the coatedolives even when they were packaged in 100% Air. Moreover, the 80% CO_2 - 20% Air proved more efficientin coated olives maintaining their quality characteristics (except for the colour of green olives), while the N2preserved the colour but not the firmness of the olives.