Pineapple - Tropical and Subtropical Fruits: Postharvest Physiology, Processing and Packaging - page 335

can be consumed directly or added to other foods, such
as cakes, pastries, and desserts (Fernandes and Rodrigues,
2008).

essential oil of Cinnamomum tamala (tejpat) (Kapoor et al.,
2008).

Nectar
Consists of a 30% mix of fruit pulp and sugar syrup to give
a final sugar level of about 12-14%.

Juice
Undersized fruit and both solid and liquid fruit compo-
nents from all Ginaca machines and trim tables are used
in pineapple juice production. The material is passed over
screens that drain the free juice and the pulp is chopped
into small pieces. Before a multistage screw press is used
to extract the pineapple juice from the solid constituents,
maximizing recovery at about 90%. Juices from liquid com-
ponents obtained during processing are then blended with
the juice from the solid fruit components with agitation in
large tanks. Juice foaming is due to the presence of gums;
up to 10 mg/liter of food-grade antifoam may be added
to reduce foaming. The juice is then heated to 60 ◦ Cand
centrifuged both to eliminate undesirable particles and to
reach 5-30% of insoluble-solids content in the pineapple
juice. The insoluble-solids are important to the perceived
mouthfeel of the product (Hepton and Hodgson, 2003). To
make a clear juice, the extracted juice is filtered through a
muslin cloth or a stainless steel filter or cross flow micro-
and ultrafiltered. Pectolytic enzymes may be used to break
down the pectins (Carvalho et al., 2008) as well as cel-
lulases (Sreenath et al., 1994). The juice is stored in tanks
with slow agitation before its use to produce single-strength
pineapple juice, blended with other fruit juices or concen-
trates to produce juice blends used as packing medium, or
evaporated to produce pineapple juice concentrate (46.5%,
61%, or 72% soluble solids). Finally the product is packed
using a hot-fill or aseptic process. To extend its shelf life
and quality, a preservative or refrigerated storage may be
used as additional barriers to microbial spoilage. No juice
should reach the market if it becomes fermented or mixed
with water. Juice packaging may be plastic bottles or bags,
coated cans, multilaminate (plastic, paper, metal foil), or
any of the newer materials. The pH of the product must
be controlled so it remains agreeable for human consump-
tion. It is a common practice to blend batches of juice
to attain proper acidity and sensory qualities. Juices from
other fruits (berries) can be blended with pineapple juice.
Such juice blends lead to novel products designed to ex-
ploit the sensory characteristics and nutritional advantages
of berry fruits and to meet the needs of modern consumers,
who increasingly buy convenience and nutritious products
to save time (Endrizzi et al., 2009). Quality and safety of
pineapple juice can be improved by adding natural phe-
nolic compounds (Arabshahi-Delouee and Urooj, 2007) or

Fruit squashes
Normally contain about 25% fruit material mixed with
sugar syrup to give a final sugar concentration of about
40%. Squashes are diluted with water prior to use.

Concentrated frozen juice
This product is prepared by direct application of heat to
pineapple juice to reduce its water content. Preservation
methods are similar as described for concentrated pulp in
which no chemical additives are used.

Jam
Jam is a mixture of sugar, pulp and/or puree (350 g/kg of
finished product) of one or more kinds of fruit and water,
brought by cooking to a suitable gelled consistency. The
extra jam requires 450 g/kg of finished product. The final
soluble dry content is typically 60% or more.

Jelly
Jelly is a semisolid product prepared by mixing fruit juice
with sugar. This mixture is cooked until the final solids con-
tents reach 65-68% soluble solids. It is hot filled for better
stability. Final textural firmness is dependent on the type
of gel-forming agent such as pectin added under controlled
acidity and solids content to assure the proper final product
texture. Preservatives are added to assure proper shelf life
at ambient temperature and to control mold growth. Silva
and Zambiazi (2008) reported preparation of conventional
and light jellies using pineapple pulp and rind residues gen-
erated in agroindustries.

Candies
The chunks are soaked for 5 hours in sugar syrup (about
60% soluble solids) containing an antioxidant, such as
ascorbic acid or a sulphiting agent, to maintain color
and are then air dried. The dried pieces are sometimes
coated with another layer of syrup and dried again. Blanch
and vacuum impregnation treatments reduce color oxida-
tion (Chen, 1995; Barat et al., 2002). Dehydrated pick-
led/candied pineapples pretreated with cysteine hydrochlo-
ride increased ascorbic acid retention and reduced color
change during storage (Mohamed et al., 1993).