title: Effect of osmotic dehydration of olives as pre-fermentation treatment and partial substitution of sodium chloride by monosodium glutamate in the fermentation profile of Kalamata natural black olives.
abstract: This study examined the effect of osmotic dehydration of Kalamata natural black olives as pre-fermentation treatment in combination with partial substitution of NaCl by monosodium glutamate (MSG) on the fermentation profile of olives. Osmotic dehydration was undertaken by immersing the olives in 70% (w/w) glucose syrup overnight at room temperature. Further on, three different mixtures of NaCl and MSG with/without prior osmotic dehydration of olives were investigated, namely (i) 6.65% NaCl - 0.35% MSG (5% substitution), (ii) 6.30% NaCl - 0.70% MSG (10% substitution), (iii) 5.95% NaCl - 1.05% MSG (15% substitution), and (iv) 7% NaCl without osmotic dehydration (control treatment). Changes in the microbial association (lactic acid bacteria [LAB], yeasts, Enterobacteriaceae), pH, titratable acidity, organic acids, sugars, and volatile compounds in the brine were analyzed for a period of 4 months. The final product was subjected to sensory analysis and the content of MSG in olives was determined. Results demonstrated that osmotic dehydration of olives prior to brining led to vigorous lactic acid processes as indicated by the obtained values of pH (3.7-4.1) and acidity (0.7-0.8%) regardless of the amount of MSG used. However, in non-osmotically dehydrated olives, the highest substitution level of MSG resulted in a final pH (4.5) that was beyond specification for this type of olives. MSG was degraded in the brines being almost completely converted to γ-aminobutyric acid (GABA) at the end of fermentation. Finally, the sensory assessment of fermented olives with/without osmotic dehydration and at all levels of MSG did not show any deviation compared to the control treatment.
authors.affiliation: Laboratory of Microbiology and Biotechnology of Foods, Department of Food Science and Human Nutrition, Agricultural University of Athens, Iera Odos 75, 11855 Athens, Greece.
authors.forename: Stamatoula
authors.initials: S
authors.lastname: Bonatsou
authors.affiliation: Laboratory of Microbiology and Biotechnology of Foods, Department of Food Science and Human Nutrition, Agricultural University of Athens, Iera Odos 75, 11855 Athens, Greece.
authors.forename: Vasilis
authors.initials: V
authors.lastname: Iliopoulos
authors.affiliation: Laboratory of Food Chemistry and Analysis, Department of Food Science and Human Nutrition, Agricultural University of Athens, Iera Odos 75, 11855 Athens, Greece.
authors.forename: Athanasios
authors.initials: A
authors.lastname: Mallouchos
authors.affiliation: Laboratory of Food Chemistry and Technology, School of Chemical Engineering, National Technical University of Athens, Zografou Campus, 5 Iroon Polytechneiou, Athens 15780, Greece.
authors.forename: Eleni
authors.initials: E
authors.lastname: Gogou
authors.affiliation: Laboratory of Process Analysis and Design, School of Chemical Engineering, National Technical University of Athens, Zografou Campus, 5 Iroon Polytechneiou, Athens 15780, Greece.
authors.forename: Vasiliki
authors.initials: V
authors.lastname: Oikonomopoulou
authors.affiliation: Laboratory of Process Analysis and Design, School of Chemical Engineering, National Technical University of Athens, Zografou Campus, 5 Iroon Polytechneiou, Athens 15780, Greece.
authors.forename: Magdalini
authors.initials: M
authors.lastname: Krokida
authors.affiliation: Laboratory of Food Chemistry and Technology, School of Chemical Engineering, National Technical University of Athens, Zografou Campus, 5 Iroon Polytechneiou, Athens 15780, Greece.
authors.forename: Petros
authors.initials: P
authors.lastname: Taoukis
authors.affiliation: Laboratory of Microbiology and Biotechnology of Foods, Department of Food Science and Human Nutrition, Agricultural University of Athens, Iera Odos 75, 11855 Athens, Greece. Electronic address: stathispanagou@aua.gr.
authors.forename: Efstathios Z
authors.initials: EZ
authors.lastname: Panagou
mesh_terms: D015169:Colony Count, Microbial; D003890:Desiccation; D004755:Enterobacteriaceae / Q000502:physiology; D005285:Fermentation; D005516:Food Microbiology / Q000379:methods; D005519:Food Preservation / Q000379:methods; D005947:Glucose / Q000378:metabolism / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007777:Lactobacillaceae / Q000502:physiology; D031658:Olea / Q000737:chemistry / Q000187:drug effects / Q000382:microbiology; D009995:Osmosis; D012492:Salts; D012965:Sodium Chloride / Q000378:metabolism / Q000494:pharmacology*; D012970:Sodium Glutamate / Q000378:metabolism / Q000494:pharmacology*; D013649:Taste; D015003:Yeasts / Q000502:physiology
chemical_list: D012492:Salts; C017082:brine; D012965:Sodium Chloride; D005947:Glucose; D012970:Sodium Glutamate
keywords: Black olives; Fermentation; Monosodium glutamate; Osmotic dehydration