Olives and Olive Oil - Tropical and Subtropical Fruits: Postharvest Physiology, Processing and Packaging - page 497

present in the fresh fruits is the cause of the final color
developed in olives. However, the evolution of color is
different under aerobic and anaerobic conditions because
different anthocyanin polymerizations take place (Romero
et al., 2004). According to these authors, aerobic process
improves the surface color of the processed olives and there-
fore their quality.
Color of olives darkened by oxidation, or Californian-
style, is due to the oxidation of ortodiphenols, hydroxyty-
rosol, and caffeic acid (Brenes et al., 1992) during the lye
treatment and air bubbling process and later polymerization
during the darkening step (Marsilio et al., 2001). Addition
of manganese cations may improve the color of ripe olives
and accelerate the oxidation rate (Brenes et al., 1995). Be-
sides this, ferrous gluconate or ferrous lactate is added to
the last wash after the lye treatment, to stabilize the color
(Garcıa et al., 1986).
Table olive texture is mainly due to changes in the cell
wall polysaccharides of the fruits. To obtain a product with
a good texture, it is necessary to pick the raw material at the
optimal stage of maturity, depending on the type of process-
ing. The preparation of green olives treatment with sodium
hydroxide makes the skin permeable and causes changes
in the cell wall that lead to loss of texture, resulting from
the degradation of pectic polysaccharides (Jimenez et al.,
1995). The addition of calcium and/or sodium salts to the
lye solution and cooling the solution gives rise to treatments
that improve olive texture and prevent the skin from break-
ing (Rejano-Navarro et al., 2008). In olives placed directly
in brine, the cellular structure remains practically intact,
which leads to less loss of consistency. However, heat treat-
ments to which olives are subjected in some preparations to
extend their shelf life may cause unwanted changes in fruit
texture. Recently, Romeo et al. (2009) showed that packing
pasteurized naturally fermented olives (cv. Nocellara et-
nea ) with brine reconstituted with sodium chloride and cal-
cium, improves the fruit texture. In the case of Californian-
style olives, these changes are very drastic due to the high
number of alkaline treatments and washes applied during
the elaboration process. This leads to a widespread loss
of pectic and hemicellulosic polysaccharides and cellulose
(Mafra et al., 2007). Nevertheless, the addition of calcium to
the final holding solution where fruits are packed increases
the ripe olive firmness (Garcıa et al., 1994).
High-quality table olives are also characterized by a
pleasant fruit flavor. This is closely correlated with the qual-
itative and quantitative composition of volatile compounds.
Flavor compound formation in table olives is a process that
develops mainly during the olive fermentation by indige-
nous lactic acid bacteria and yeasts, together with a variety

of contaminating micro-organisms which produce volatile
compounds from major fruit constituents through various
biochemical pathways (Sabatini and Marsilio, 2008). Those
authors have characterized volatile compounds in Spanish-
style, Greek-style, and Castelvetrano-style green olives of
the 'Nocellara del Belice' cultivar. Their results suggested
that different processing technologies significantly affected
the volatile compounds of samples and meaningful differ-
ences in aromatic profiles could cause differences in quality.
Hernandez et al. (2007) reported the presence of yeasts with
esterase and polysaccharolytic activities in green olive fer-
mentation suggesting an important role of these yeasts in
the final sensory characteristics of the fermentations. Dur-
ing the later stages of the ripe olive storage of 'Manzanilla'
and 'Hojiblanca' cultivars in acidified brines, Rodrıguez-
G omez et al. (2010) detected the yeast specie Candida
boidinii with a strong lipase activity which can modify the
characteristics of the fat in the fruit. The role of yeasts in
table olive production has been recently reviewed (Arroyo-
L opez et al., 2008).

Alterations
The quality of the table olive may be seriously affected
by the development of abnormal fermentations due to the
presence of unwanted micro-organisms during the process.
Several types of spoilage are recognized, which may not
be a risk to health but depreciate the quality of the final
product due to deleterious changes in the olive sensory
characteristics (Garrido-Fernandez et al., 1997).
The spoilage known as fish-eye and gas-pocket is char-
acterized by the formation of pockets or blisters in the olive
flesh which may extend to the pit of the fruit. This is caused
by the accumulation of gases inside (CO 2 and H 2 )pro-
duced by the action of Gram-negative bacteria. Softening
of table olives is usually caused by micro-organisms with
pectinolytic enzymatic activity (bacilli, yeasts, and molds).
Shriveling is frequent in turning-color olives. It is produced
either by the use of high salt concentrations or by an exces-
sive gas accumulation in the interior of fruits.
In the case of green table olives Spanish-style, putrid
and butyric fermentations may develop due to the growth of
micro-organisms of the genus Clostridium. These spoilages
alter the aroma and flavor of the product. During preser-
vation of the fermented product, the spoilage called “za-
paterıa” may arise, due to the growth of bacteria of the
genera Clostridium and Propionibacterium. The volatile
compounds from their metabolism (Monta no et al., 1992)
give the olive a very unpleasant smell and flavor.
The 'Gordal' Spanish cultivar processed as Spanish-
style table olives has long developed an alteration in color,