Use of a lactic acid bacteria starter culture during green olive (Olea europaea L cv Ascolana tenera) processing

Abstract

Among the Italian olive germplasm, 'Ascolana tenera' is one of the best varieties for table olive production. This research addressed the impact of different processing types (Greek-style and Spanish-style) on the fermentation and phenolic composition of olive fruit. In particular, the effects of a lactic acid bacteria (LAB) starter culture on the fermentation of naturally green olives processed according to the traditional Greek method were studied. Results revealed that Spanish-style processing produced a dramatic loss of total phenolics, while natural olive processing favoured a higher retention of biophenols. Oleoside 11-methylester, a phenol-related compound, and hydroxytyrosol, tyrosol, vanillic acid, 3,4-dihydroxyphenylglycol, oleuropein and oleuropein aglycons, as the main phenols, were detected in olive fruit. More interestingly, this research indicated that inoculation with LAB affected the pH, total acidity, microbial profile and palatability of olives. Olives fermented with the LAB starter culture were perceived by panellists to be less bitter and more aromatic than those spontaneously fermented. Thus the use of LAB inoculants during olive fermentation could be applied with the currently available technology.

Nutritional and Sensory Quality of Table Olives

“…To reduce the debittering phase, several researches have evaluated the use of selected oleuropeinolytic lactic acid bacteria (LAB) as starter cultures in Greek-style olive processing. Lactobacillus plantarum (Ciafardini et al, 1994;Marsilio et al, 1996;Marsilio & Lanza, 1998;Marsilio et al, 2005;Panagou et al, 2008) and Lactobacillus pentosus (Panagou et al, 2003;Panagou et al, 2008;Servili et al, 2006), in addition to developing a fast growth and a good acidifying capacity even in the presence of high concentrations of salt (brine), were able to grow in the presence of phenolic compounds (known for their antimicrobial action) and, thanks to the marked oleuropeinolytic activity, degraded the oleuropein in no-bitter compounds, reducing thus considerably the time of debittering.…”

Microbiological Aspects of Table Olives

“…However, interest in developing starter cultures to be used in table olives is increasing. LAB have long been employed in fermentation as a food preservation technique owing to their progressive acidification of the fermenting brine with a consequent pH decrease (Marsilio et al, 2005). In addition, the use of LAB could standardize olive fermentation and reduce the use of highly polluting chemicals as NaOH (lye solution), contribute significantly to storage preventing microbial spoilage, and improve flavour.…”

Effects of maturation and processing technologies on nutritional and sensory qualities of Itrana table olives

“…To reduce the debittering phase, several researchers have evaluated the use of selected oleuropeinolytic lactic acid bacteria (LAB) as starter cultures in Greek-style olive processing. Lactobacillus plantarum (Ciafardini et al, 1994;Marsilio et al, 1996;Marsilio and Lanza, 1998;Marsilio et al, 2005;Panagou et al, 2008), Lactobacillus pentosus (Panagou et al, 2003;Panagou et al, 2008;Servili et al, 2006) and other LAB species such as Lactobacillus brevis and Pediococcus pentosaceus (Ghabbour et al, 2011). In addition to developing rapid growth and good acidifying capacity even in the presence of high concentrations of salt (brine), they were able to grow in the presence of phenolic compounds (known for their antimicrobial action) and, thanks to the marked oleuropeinolytic activity, degraded the oleuropein in non-bitter compounds, thus considerably reducing the time required for debittering.…”