Avocado - Tropical and Subtropical Fruits: Postharvest Physiology, Processing and Packaging - page 427

Besides the avocado products mentioned above, novel
products have been developed using osmotic dehydration
and mixing with maltodextrins and sodium chloride. This
process has been able to maintain color and microbial sta-
bility (Schwartz et al., 2003).

proved and preferably belong to the GRAS category as per
FDA classification.

PROCESSING AND PROCESSED PRODUCTS
Some of the earliest processed products from avocado were
avocado oil, slices, and halves (marketed in Mylar bags).
In recent years, in addition to traditionally prepared gua-
camole, processing of avocado has become an important
component of the avocado industry (Hoffman et al., 2002).
The growing popularity of Mexican cuisine and the nutri-
tional and health benefits of avocado have been a major rea-
son to expand avocado processing (Hoffman et al., 2002).

Packaging of minimally processed products
The pulp of avocado in guacamole products may be vac-
uum packed and sealed into coextruded five-layer bags,
with high O 2 barrier properties. Processors usually pack
in6lb( ∼ 2.7 kg) bags since most of their customers are
restaurants, but they also have a 250 g package for retail
marketing. In the case of supermarkets in Mexico, where
small amounts of guacamole are prepared, they are usually
packed in small plastic containers of 200 ml. Polymers with
a high barrier to oxygen are preferred, such as the ones de-
scribed by Catala and Gavara (2000), which are copolymers
of polyvinylidene chloride (PVC), aromatic polyamides,
and ethylene vinyl alcohol (EVOH).

Preparation operations
Some of the preparatory steps (grading, cleaning, washing,
peeling, and cutting) have been discussed in the subsection
under pretreatments for minimally processed or fresh-cut
avocados; the next step in processing is blanching.
Several attempts have been made to process avocados
as puree or guacamole with extended shelf life. Microwave
treatment offers an alternative for the blanching of fruits and
vegetables since the application of high temperatures for
short times often results in minimal damage (Dorantes and
Parada, 2005). Furthermore, previous studies have shown
that better retention of color and lightness is obtained when
avocado puree is processed in a microwave oven. However,
a great loss of flavor takes place when this commodity is
treated by heat. The application of a combined treatment
consisting of microwaves, pH adjustment, and the addition
of avocado leaves to the puree minimizes flavor loss and
results

Microbiological issues/food safety aspects
Microbiological contamination of some fresh-cut vegeta-
bles is potentially more harmful than present in meat or
other animal products. This is because vegetable products
are usually consumed without previous heat treatment that
inactivates pathogens. Microbial flora of fruits and veg-
etables is essentially of the same in the fields, mainly
composed of Pseudomonas spp., Erwinia hervıcola, and
Enterobacter aglomerans. Other organisms such as the
acidolactic bacteria Leuconostoc mesenteroides and Lac-
tobacillus spp. are also found frequently, besides several
species of yeast. The main pathogens are Listeria monocy-
togenes, Salmonella, and Clostridium botulinum. Microbial
load can be minimized by applying a hazard analysis and
critical control points program (HACCP) in the production
process (Martınez et al., 2005). It is noteworthy that the
facilities that process avocado should include a reception
area and a washing and sanitizing area separate from the
zone where the fruits are cut and mixed with condiments
and additives, with high standards of hygiene practiced in
all areas.

in a product with acceptable characteristics

(Guzman et al., 2002).

Canning: fruit and guacamole
Canning of avocado was attempted as earlier as 1916 by
Cruess and Mitra. They canned avocados in various kinds
of brines and syrups. Their results showed that salt brines
were unsatisfactory in all cases, while an acrid taste devel-
oped in avocados canned in water or brines. The use of 60%
cane sugar syrup and processing at 82.2 ◦ C (180 ◦ F) gave ex-
cellent quality results, with rich flavor close to that of fresh
fruit. Furthermore, an improvement in flavor was observed
with added lemon juice in the canning syrup (Cruess and
Mitra, 1916).
Griebel and Kargel (2008) patented a method for pro-
cessing avocado pulp into guacamole by heating it up to a
temperature enough to substantially denature native degra-
dation enzymes, combined with a pH higher than 8. The
temperature must be at least 71 ◦ C (160 ◦ F) to reduce the

Quality attributes: physical, chemical, and sensory
The physical attributes of fresh avocado required by the
market have been discussed in a previous section. Qual-
ity attributes of minimally processed products include a
green characteristic color, and the added chemicals must
not change the original flavor. All additives must be ap-