Quality assessment of mineral-enriched natural cracked green table olives

Abstract

This study employed Response Surface Methodology (RSM) to assess the effect of fortifying Traditional Aloreña de Málaga olives with KCl, CaCl₂, and MgCl₂ (totalling 2.5 %) on their physicochemical and sensory profiles. The brines also included 2.5 % NaCl, achieving a total salt concentration of 5 %, with the process being a model for natural table olives. RSM showed that pH decreased with higher CaCl₂ and MgCl₂, while firmness increased with elevated CaCl₂ but was slightly reduced by MgCl₂. Moisture content peaked at the barycentre of the design, and luminance values rose with increased MgCl₂ levels. The a∗ value (indicating greenness) improved with higher KCl concentrations. Bitter scores intensified with CaCl₂, though KCl and MgCl₂ somewhat mitigated this effect. Crunchiness was lowest with equal proportions of all salts but highest when either KCl or a combination of CaCl₂ and MgCl₂ was maximised. The overall score and purchasing predisposition were primarily influenced by bitter (which had a negative impact) and odour/smell (which had a positive impact). The optimal salt combination for achieving the highest favourable and lowest negative quality attributes was (0.70 g KCl, 0.80 g CaCl₂, and 1.00 g MgCl₂)/100 mL brine, situated near the KCl-CaCl₂ boundary at a 1:3 ratio, with maximum MgCl₂. Six treatments achieved promising overall scores and purchasing predisposition, suggesting strong market potential.