2.2. Olive processing
Black olives cv. “Kalamata” were supplied from an olive processing
factory in the region of Kalamata (Greece) and green olives cv.
“Chalkidikis” treated with NaOH (2% w/v for 8 h) were supplied
from an olive processing factory in the region of Chalkidiki (Greece)
and analyzed as industrial processed product. Olives originating from
the same fresh product lots of industrial production (but not alkali
treated in case of green olives) were elaborated in our laboratory.
After washing with tap water, 500 g of olives were placed in sterile
glass vessels and covered with 500 ml of sterile brine. For each olive variety
four treatments were prepared: In the first treatment the fermentation
was carried out in Brine A containing 2.3% NaCl supplemented
with 32.3 mM Ca-acetate and 33.9 mM Ca-lactate (Tsapatsaris and
Kotzekidou, 2004) without addition of starter culture (control treatment);
in the second treatment Brine A was inoculated with OSC; in
the third treatment the fermentation was carried out in Brine B containing
4% NaCl without addition of starter culture (control treatment); and
in the fourth treatment the fermentation Brine B was inoculated with
OSC. The pH of both brines was adjusted to 5.0 with acetic acid. The
olives remained in brine for equilibriumfor 24 h at 22 °C and then inoculated
with OSC as wet inoculum(7.95–8.36 log CFU/ml). NaCl concentration
during fermentation was maintained at the level fixed for each
brine by periodical adding of solid salt. All fermentation processes
were carried out at a controlled temperature of 22 °C mixing periodically
the brines. The experimental trials were carried out in triplicate. After
90 days of fermentation samples from each treatment were taken for
physicochemical and microbiological analyses and the determination
of the main phenolic compounds in olive pulp. The control samples
after 20–30 days of fermentation showed formation of a mold layer
on the top of the brine and signs of initial spoilage (softening of olives)
due to the low salt concentration of the fermentation brines; for this
reason they were not further analyzed. Industrial processed olives
were purchased from the two factories after 90 days of fermentation
and were analyzed. All measurements were performed in three independent
samples.