DEVELOPMENT OF AN EFFICIENT CASHEW NUT SHELLER
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Date
40833
Authors
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Journal ISSN
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Publisher
University of Agricultural Sciences GKVK, Bangalore
Abstract
Cashew (Anacardium occidentale L.) is an evergreen tropical tree which produces a
valuable nut that is widely consumed as snacks all over the world. The raw cashew nut
requires some kind of thermal pretreatment that aid in deshelling of the nut to obtain
valuable inside kernel. Commercially, three methods of pretreatment are followed before
shelling raw cashew nut: drum roasting, oil bath roasting and steam roasting. Except in
Kerala, the cashew is mostly processed in India by steam roasting method wherein, a
hand-cum-pedal operated (splitting mechanism) or fully hand operated (twisting
mechanism) cashew nut shellers are being used. The shelling process is laborious and
involves drudgery. The above two traditional shellers were modified as completely foot
operated shellers and the two prototypes shelling performance were studied. Raw
cashew nuts were pretreated by steaming at different pressures (0.0, 0.5, 1.0 kg/cm2) and
durations (15, 20, 25, 25, 30, 35, 40 and 45 min) and were used to study shelling
performance of improved cashew shellers. The cutting strength (kgf) of steam cooked
nuts as measured by a texture analyzer ranged from: 31.72 – 37.45 at 0.0 kg/cm2; 30.70-
35.82 at 0.5 kg/cm2; and 25.65 – 32.54 at 1.0 kg/cm2, depending upon the steaming
duration while the uncooked raw nut recorded higher value of 45.17 ± 8.72 kgf.
Two prototype cashew nut shellers (with splitting/twisting mechanisms) were
developed and their shelling performance was evaluated using different steam cooked
nuts. The mean values of shelling capacity (kg/h), shelling efficiency (%), whole kernel
recovery (%) and kernel breakage (%) in the case of the modified foot operated cashew
sheller with splitting mechanism were respectively 4.304, 96.9, 88.0 & 12.0 as against
the values of 3.746, 97.6, 82.0 & 18.0 for traditional hand-cum-foot operated unit.
Similar performance characteristics values for improved foot operated cashew sheller
with twisting mechanism were respectively 4.237, 97.7, 74.2 & 25.8 which were very
nearly same as the data of 4.685, 98.0, 75.3 & 24.7 recorded for the conventional hand
operated cashew sheller. Both the improved foot operated shellers are easy to operate
which eliminate shoulder fatigue faced by the operators currently. The Cost-Benefit
Ratio of operating the Modified Cashew Sheller with splitting mechanism was 1:1.44
and the same for the Improved Cashew Sheller with twisting mechanism was 1:1.45.
Therefore, the improved prototype cashew nut shellers have potential to replace
respective conventional gadgets and may be recommended to deshell steam roasted
cashew nuts.