3.5.2. Free fatty acid content
Free fatty acids (FFA) content is considered to be an indicator
of oil quality in food industry as it leads to development of
off-flavor in oils and fried products. FFA was found to increase
with an increase in frying cycles in case of heating as well as
frying. The percentage of FFA of fresh RBO was 0.15. FFA was
found to increase after heating and frying for 1–6 consecutive
cycles, from 0.3 to 0.44% and 0.48% respectively. The change in
FFA after frying was found to be more in comparison to only
heating (Fig. 3a). The moisture coming from the fried product
accelerates the hydrolysis of oil. It is known that water can
promote the hydrolysis of triacylglycerols to form a combination of mono and diacylglycerols, glycerol and free fatty acids.
The increase in FFA was due to the cleavage and oxidation of
double bonds to form carbonyl compounds, which oxidized
to low molecular weight fatty acid during frying (Irwandi and
Cheman, 2000; Ramadan et al., 2006). The increase in FFA level
is not a very reliable parameter for the degradation of frying oil,
because it is difficult to differentiate between the FFA formed
by oxidation or by hydrolysis (Ramadan et al., 2006). Moreover,
low molecular weight FFA may be lost through volatilization
during frying (Sulieman et al., 2006).
3.5.2. Free fatty acid contentFree fatty acids (FFA) content is considered to be an indicatorof oil quality in food industry as it leads to development ofoff-flavor in oils and fried products. FFA was found to increasewith an increase in frying cycles in case of heating as well asfrying. The percentage of FFA of fresh RBO was 0.15. FFA wasfound to increase after heating and frying for 1–6 consecutivecycles, from 0.3 to 0.44% and 0.48% respectively. The change inFFA after frying was found to be more in comparison to onlyheating (Fig. 3a). The moisture coming from the fried productaccelerates the hydrolysis of oil. It is known that water canpromote the hydrolysis of triacylglycerols to form a combination of mono and diacylglycerols, glycerol and free fatty acids.The increase in FFA was due to the cleavage and oxidation ofdouble bonds to form carbonyl compounds, which oxidizedto low molecular weight fatty acid during frying (Irwandi andCheman, 2000; Ramadan et al., 2006). The increase in FFA levelis not a very reliable parameter for the degradation of frying oil,because it is difficult to differentiate between the FFA formedby oxidation or by hydrolysis (Ramadan et al., 2006). Moreover,low molecular weight FFA may be lost through volatilizationduring frying (Sulieman et al., 2006).
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