Page 93 - rise 2017

Detection of Added Plastics in the Frying Oils Using Differential Scanning Calorimetry (DSC)
combined with Principal Component Analysis (PCA)

1, a
1, c
1, d
Mualim, M. S. 1, b * Nur Azira, T. , Muhamad Shirwan, A. S. and Nurrulhidayah, A. F.

1 International Institute for Halal Research and Training (INHART), Level 3, KICT Building,
International Islamic University Malaysia (IIUM), Jalan Gombak, 53100, Selangor, Malaysia

a b c
aziratukiran@iium.edu.my, mualim.salleh@gmail.com, shirwansany@iium.edu.my,
d nurrulhidayah@iium.edu.my

Abstract
There was a controversy on the claimed usage of plastic bags and straws which were intentionally
added in the frying oil just to make fried foods crunchier. Thus, the present study was aimed to assess
the feasibility of Differential Scanning Calorimetry (DSC) coupled with Principal Component
Analysis (PCA) in detecting the added plastics in the frying oils. The method used was able to detect
the added plastics in the frying oils that have been used to fry banana, onion and chicken. The simple
approach employing DSC and PCA reported in this study may provide a useful tool for food safety.
Keywords: Banana fritter, Fried Onion, Fried Chicken, Palm Oil, Differential Scanning Calorimetry
(DSC), Principal Component Analysis (PCA).

Introduction
Cooking oils have been a major component for stall vendors to fry their food products. For example
bananas fritter which is a very popular food in the Nusantara. However, there was a controversy on
the claimed usage of plastics and straws which were intentionally added in the frying oil just to make
fried foods crunchier. The chemicals in the plastics can give harmful effects to the human body. For
example, one of the chemical compounds, which is phenyl hydroxylamine, may damage the
hemoglobin in the bloodstream. Therefore, it is useful to establish methods for the cooking oil
authentication.
Currently, there were several techniques have been used in regard of edible oil authentication
such as differential scanning calorimetry (DSC), reversed phase high performance liquid
chromatography (RP-HPLC), gas chromatography (GC) [1,2], Raman and Infrared spectroscopy [3].
However, DSC is among the popular technique as it is easy to handle and cost effective [1, 4, 5-14].
Recently, DSC combined with chemometric has been used in some food authentication studies. This
approach was applied in order to indicate or classify the differences and similarities of different food
components and their chemical composition. Thus, the aim of this study is to assess the feasibility of
Differential Scanning Calorimetry (DSC) coupled with Principal Component Analysis (PCA) in
detecting the added plastics in the frying oils. Cooking oil that added with plastic of banana flitter,
fried chicken and fried onion were analyzed.

Materials and methods
Materials
Palm oil (Saji brand, Delima Oil Products Sdn Bhd), banana, onion, plastic (7 cm × 9 cm) and straw
(Length: 18.05 cm; Diameter: 0.8 cm) were purchased from the local retail shop. Chicken breast was
purchased from the local wet market. The stove used was an electric stove with temperature indicator.

Sample preparation
Chicken breast, banana, and onion were cut into little pieces with 1 cm × 1 cm dimension. Six
hundred milliliter of palm oil was pre-heated for 5 minutes at 180°C. Subsequently, the samples were
deep-fried in the palm oil for 5 min at 180°C following the configuration as shown in Table I. The
used fried-oils were used as samples. The control of this study was palm oil that heated for 10 min at
180°C.