Coconut - Tropical and Subtropical Fruits: Postharvest Physiology, Processing and Packaging - page 163

milk is spray dried at a temperature range of 100 ◦ -150 ◦ C
with a desired flow rate (Rastogi and Raghavarao, 2006).
The spray-dried coconut milk available in the market has
good shelf life stability. Moisture content is important in
maintaining a stable product free from rancid or soapy fla-
vor. To minimize the fat hydrolysis as well as the microbial
growth, the moisture content of the milk powder should
be less than 2.5%. For international marketing purposes,
the fat content of the spray-dried milk powder should not
be lower than 60% (MS, 1994; SLS, 2007). Apart from
being a convenient product, spray-dried coconut milk is
also intended as a substitute for fresh coconut milk in the
non-coconut-growing areas. To retain fresh coconut milk
properties, the powder should be white, nonoily, and have
a natural coconut flavor.

either by sun drying or kiln drying, while large-scale pro-
ducers may use mechanized dryers. The dried parings need
to be disintegrated into smaller pieces prior to feeding into
oil expellers. In the subsequent step, the crude oil extracted
would be subjected to sedimentation and filtration.
As shown in Table 9.7, the general quality characteristics
of paring oil would be slightly different from those of either
virgin coconut oil or copra-derived oil. Generally, the FFA
content of paring oils supplied by the oil milling industry
may exceed the limit shown in Table 9.7. The microbial
spoilage of the raw material prior to processing could be
partly attributed to the higher FFA content of paring oil. It is
already known that excessive moisture might cause shorter
chain fatty acids in coconut oil to undergo hydrolysis. If
more lauric acids are released through hydrolysis, the oil
may tend to produce unpleasant soapy odor (Jones and
King, 1996). As the limit of FFA content specified for
edible quality oil is 0.1%, paring oil is often required to
be refined (Orthoefer and Cooper, 1996). The fatty acid
composition of paring oil is also slightly different from the
other two types of oil. Paring oil is usually found to have
higher iodine value mainly due to the increased amounts
of oleic (C 18:1 ) and linoleic (C 18:2 ) acids (Table 9.7). As a
result, the oxidative stability of coconut paring oil is lower
than that of ordinary coconut oil.

Coconut oil processing
Coconut oil extraction is an important industry in many
parts of Asia and the Pacific region. For extraction of co-
conut oil, either wet or dry processing methods can be
employed. Dry process is the simplest and the most eco-
nomical method for oil extraction. In this method, coconut
kernel is subjected to dehydration at the initial stage to ob-
tain copra or dried coconut kernel pieces. Copra is then
cut into smaller pieces before feeding into screw press, hy-
draulic press, or bridge press for expulsion of oil (Jayalak-
shmy et al., 1980). As a common practice, copra pieces are
heated in a dryer prior to oil extraction so that the moisture
content would be lower while the flavor formed by roasting
could be inherited by the oil (Jayalakshmy and Mathew,
1990). When copra pieces are placed in a screw press ex-
pellers, the high pressure causes oil to ooze out of the copra.
An opening on the underside of the girder allows oil to be
poured into a collection vessel. The oil thus collected is
passed into a tank, where it is kept for a day or two for the
finer particles to undergo sedimentation. Immediately after
sedimentation, oil is pumped into a filter press for filtering.
The filtered oil is finally sent to a storage tank, from where
it can be packaged for the retail or bulk markets.

Virgin coconut oil
Virgin coconut oil (VCO) is a product obtained from fresh
mature kernels by mechanical or natural means with or
without the application of heat (Bawalan and Chapman,
2006). VCO should be produced in a more natural way
without chemical refining, bleaching, or deodorizing oper-
ations. Although VCO may be processed either by a wet or
dry processing method, there are wide differences between
them with regard to extraction efficiency, production cost,
and final product quality.

VCO production by wet processing method
In the wet process, VCO is produced directly from the
fresh comminuted coconut kernel by taking the milk out
of it. Coconut milk is essentially an oil-in-water emulsion
stabilized by proteins. For the recovery of oil, the protein
bonds associated with the milk need to be broken down by
the application of heat, enzymes, or some other mechani-
cal force. Centrifugation has been found to be an effective
mechanical force to separate cream from coconut milk.
After heating the cream at 60 ◦ C, clear oil could be recov-
ered through a proper filtration process. VCO production
is also possible through natural fermentation of coconut

Coconut paring oil
Coconut paring comes from the outer brown testa of the
coconut kernel that is rich in oil. As removal of the paring
from the kernel is a requirement for processing of products
such as desiccated coconut, coconut cream, and milk pow-
der, a substantial quantity of paring is generated on a daily
basis. Since paring is a part of the kernel, it is dehydrated
separately to extract oil that is known as coconut paring oil.
In small-scale operations, dehydration of paring is done