Guava - Tropical and Subtropical Fruits: Postharvest Physiology, Processing and Packaging - page 205

Table 11.2. Physicochemical characteristics of fresh guava purees.

White Puree Pink Puree

Total soluble solids ( ◦ Brix) 10 . 2 10 . 2

pH 3 . 65 3 . 85

Titratable acidity as citric acid (%) 0 . 72 0 . 62

Reducing sugars as dextrose (%) 4 . 68 4 . 04

Pectin as calcium pectate (%) 0 . 88 0 . 92

Ascorbic acid (mg/100 g) 267 106

Crude fiber (%) 0 . 73 0 . 86

Source: Harnanan et al. (2001).

The aroma profile of fresh pink guava fruit puree showed
about 48 compounds, with a predominance of terpenic hy-
drocarbons and 3-hydroxy-2-butanone, the latter imparting
an acidic, pungent flavor (Jordan et al., 2003).

guava juice is produced by the addition of pectic enzymes
to guava puree. Together with the enzymes, the use of fining
agents may produce clearer juices with higher yields. More-
over, centrifugation together with filtration technologies is
commonly used after the enzyme treatment to remove the
suspended materials, producing a clearer juice (Brasil et al.,
1995; Dauthy, 1995; Chopda and Barrett, 2001).
The use of enzyme treatments may either increase or
reduce the ascorbic acid content of guava juice. The effect
of the enzyme on the fruit peel allows for the release of
a large amount of ascorbic acid, while excessive exposure

Nectars, clarified juices, and concentrates
Guava puree is highly viscous and is thus usually diluted
(nectar) or subjected to enzymatic treatments (clarified
juice) before drinking.
Commercially, guava nectar is formulated using water,
sugar or sweeteners, acidulants, and other additives, but
the composition depends on the producer. The heat treat-
ment must assure the microbiological safety of the product,
although excessive time/temperature affects its nutritional
and sensory quality (Zainal et al., 2000). Pasteurization of
the nectar at 90 ◦ C for 60 sec leads to a product with a
considerable amount of bioactive compounds (Table 11.3)
which are stable during storage (Silva et al., 2010). Com-
mercially, guava nectars are processed either by the hot fill
or aseptic process (Fig. 11.5).
Depending on the country, the consumers may prefer
grit-free, haze-free, or clear juices, instead of the cloudy
product extracted directly from the guava fruit. Clarified

Guava Puree/Pulp

Enzymatic treatment

Fining

Water addition

Flocculation

Formulation (sugar,
citric acid, etc.)

Centrifugation/Filtration

Nectar

Clear juice

Table 11.3. Bioactive compounds of hot-filled or
aseptically packaged guava nectar (mg/100 ml).

Clarified Juice

Heat treatment

Bioactive Compound Hot Filling Aseptic Process

Bottling

Vitamin C 33 . 9 43 . 0

Cooling

Carotenoids 1 . 20 0 . 93

Anthocyanins 0 . 33 0 . 18

Storage

Phenolic compounds,
tannic acid equiv.

114 . 81 87 . 65

Figure 11.5. Flow diagram of guava nectar and
clarified juice processing.

Source: Adapted from Silva et al. (2010).