Kesan Parameter-Parameter Penggorengan Ke Atas Perubahan-Perubahan Fizikal Keropok Dan Papad Semasa Penggorengan Celup
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Date
1995-05
Authors
Chanderan K, Vasanti Nair
Journal Title
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Abstract
On deep-fat frying, the half-products of keropok and
papad, undergo physical changes such as moisture loss
(ML), oil absorption (OA) and linear expansion (LE) which
give the end-products their desirable characteristics.
Studies were conducted to investigate the effects of the
frying parameters of oil temperature (T), time (t) and
initial moisture content (M) of the half-products, and the
interrelationships of their effects, on these physical
changes.
A finding common to both products is that little or
noML, OA or LE occurred when T, t or M was below a critical
level, designated as Tcr ' tcr and Mer' respectively.
On exceeding Tcr ' tcr and Mcr ' these physical changes
increased drastically before reaching either a plateau or
a peak. The critical frying temperature (T cr ) of keropok
was found to be closely related to its heat of desorption
at any particular initial moisture content since deep-fat
: ,
frying can be approximated to a drying or moisture removal
LUL~ ~U~g~~L~ lna~ enougn energy has to be
provided to overcome the heat of desorption before any
significant physical change can take place.
Moisture lost was quantitatively replaced by the oil
absorbed, with ML and OA exhibiting excellent correlation.
The major factor responsible for LE was rapid vaporization
of --water which occurred under conditions where all three
critical levels were exceeded. The optimum frying conditions
tri attain maximum LE for (a) keropok are T = 190-
200oC, M = 15-20% (d.b) and t = 40 s, and (b) papad are T
= 190-200oC, M = 10-15% (d.b.) and t = 20 s.
The microstructural changes of papad during deep-fat
frying under different conditions revealed that native
starch granules played little, if any, role in linear
expansion of the product. Rather, expansion was due the
stretching of protein-mucilage matrix surrounding the
starch granules as a result of rapid vaporization of
water .
Description
Keywords
Technology Industry , Effects Of Frying Parameters