Guava - Tropical and Subtropical Fruits: Postharvest Physiology, Processing and Packaging - page 203

Drying
Drying is used for either the production of guava infusions
or guava snacks. In the first case, unripened fruits are usu-
ally used, and guavas are sliced transversally to the central
axis. Drying is carried out without previous treatment, and
the fruit must be rehydrated before consumption.
Conversely, for the production of guava snacks, the seeds
are usually removed. The guava shells (halved fruits without
seeds) may be cut into thin slices (from 16 to 32 slices per
fruit) or small pieces prior to drying. Pretreatments such
as blanching and OD are usually carried out in order to
improve the color, texture, and nutritional characteristics
of the dried product. Dried guavas pretreated by OD were
found better in quality as evaluated by a sensory panel,
with improved color and flavor and greater sweetness and
juiciness than fruits without such a pretreatment (Sanjinez-
Argandona, 2005).

Raw guava

Sorting

Washing/Sanitizing

Peeling

Cutting/Slicing/Seed removal

Washing/neutralization

Canning Cooking

Exhaustion Draining

Canning in syrup
Canned guava (guava in syrup) is produced by thermal
processing the fruits in sucrose and/or glucose solutions
(

Pasteurization Bottling Syrup

Cooling Pasteurization

35 ◦ -40 ◦ Brix). Artificial sweeteners may be used to sub-
stitute sugar for the processing of diet products. Sometimes,
a preservative and acidulant such as sorbic acid, sodium
benzoate, potassium sorbate, and/or citric acid is added to
the syrup. More frequently, the guavas are processed in
halves with their seeds removed (guava shells), although
in some countries, such as Mexico, canning of the whole
fruit is not uncommon. The fruits may be cooked either
before or after canning (Fig. 11.3). In the first case, the
guavas are cooked in 40 ◦ -50 ◦ Brix syrup until soft. The
syrup is then drained and the fruits are bottled in fresh, hot
syrup before closure and pasteurization. In industrial pro-
cesses, the fruit and syrup are usually added together before
thermal processing. In both cases, after canning, a thermal
treatment is carried out with boiling water (10-20 min),
followed

∼

Cooling

Storage

Storage

Figure 11.3. Flow diagram of canned guava
processing.

guava may be improved by the addition of calcium salts
in the syrup, allowing for a minimization of the negative
effects of temperature on the texture of the guava (Sato
et al., 2006).

Freezing
Though the effect of shelf life on some properties of frozen
guava, such as total acidity and the sensory properties has
been evaluated, there are not many studies concerning the
freezing of guava. It was observed that storage (

37 ◦ -40 ◦ C by fast cooling to (Martin and

Kato, 1988).
The effect of cooking time (up to 60 min) and temperature
(60 ◦ -90 ◦ C) on the mass transfer kinetics as well as on the
color and texture of red guava in syrup has already been
evaluated (Sato et al., 2005). Higher mass transfer rates
(water loss and sugar gain) were observed within the first
30 min of processing. The effect of temperature was much
more significant than the time of processing on the color
of guava in syrup. The higher the process temperature, the
more intense is the redness of the fruit, although softening
may be observed with increasing temperatures, especially
for fruits processed at 90 ◦ C. Thus the texture of canned

20 ◦ C, up
to 6 months) of guava halves frozen in liquid nitrogen led to
a decrease in fruit acidity and rejection by the sensory panel
owing to loss of flavor and excessive softening (ICAITI,
1976).
This technique is not usually carried out with fresh fruit
since the fresh fruit is highly chill sensitive, being applied
more frequently for enhancing the shelf life of processed
products such as pulps.

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