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European Journal of Applied Sciences – Vol. 10, No. 5
Publication Date: October 25, 2022
DOI:10.14738/aivp.105.13045.
Pambou-tobi, N. P. G., Sompila, A. W. G. T., Niamayoua, R. K., & Linder, M. (2022). Comparative Study on Frying Performance of
Three Different Oils for the Preparation of Ripe Plantain Banana. European Journal of Applied Sciences, 10(5). 94-113.
Services for Science and Education – United Kingdom
Comparative Study on Frying Performance of Three Different Oils
for the Preparation of Ripe Plantain Banana
N. P. G. Pambou-tobi
Institut de Recherche en Sciences de l’Ingénieur
Innovation et Technologie, cite scientifique
route de l’auberge de Gascogne, Brazzaville, Congo
Laboratoire de Bioprocédés alimentaires et médicaux
ENSP-UMNG, BP. 69 Brazzaville, R. Congo
Ecole Nationale Supérieure Polytechnique, Université Marien
NGOUABI, Brazzaville
Arnaud W. G. Tamba Sompila
Institut de Recherche en Sciences de l’Ingénieur
Innovation et Technologie, cite scientifique
route de l’auberge de Gascogne, Brazzaville, Congo
Laboratoire de Bioprocédés alimentaires et médicaux
ENSP-UMNG, BP. 69 Brazzaville, R. Congo
Ecole Nationale Supérieure Polytechnique, Université Marien
NGOUABI, Brazzaville
Rosalie Kama Niamayoua
EPRAN-Congo, Pôle d’Excellence en Alimentation et Nutrition
Faculté des Sciences et Techniques, Université Marien NGOUABI
Brazzaville
Michel Linder
Université de Lorraine - Laboratoire d’Ingénierie des
Biomolécules (LIBio), 2 avenue de la Forêt de Haye
TSA 40602 54518 France
ABSTRACT
In this study, the effect of traditional frying on oils degradation namely frial oil (FO),
soybean oil (SBO) and refined blanded deodorized palm olein oil (RBDPOo) was
investigated. Oils degradation was monitored by measuring the free fatty acids
(FFA), peroxides (PV), p-anisidine (p-AV),) iodine value (IV), totox value (TxV), total
polar compounds (TPC), fatty acid composition and C18:2/C16:0 ratio, viscosity,
conjugated dienes (CD) value and oil color. Oils samples were taken every 4 h of
frying during 10 consecutive days. Values of all physic-chemicals measures
significantly changed with frying and type of fat. Values of FFA, p-AV, TPC, CD, TxV,
ΔE and viscosity increased significantly, whereas IV and C18:2/C16:0 ratio
decreased significantly at the end of the frying processes. Excepted PV, where the
values reached a maximum and then decreased at to final frying. These results
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95
Pambou-tobi, N. P. G., Sompila, A. W. G. T., Niamayoua, R. K., & Linder, M. (2022). Comparative Study on Frying Performance of Three Different
Oils for the Preparation of Ripe Plantain Banana. European Journal of Applied Sciences, 10(5). 94-113.
URL: http://dx.doi.org/10.14738/aivp.105.13045
suggested that a traditional frying process has an impact on degradation on edible
oils.
Keywords: Alteration, frying, oxidation, Ripe plantain banana, stability, viscosity
INTRODUCTION
Deep fat frying is one of the oldest and popular [1]; [2] cooking method used throughout the
world. The method consist in immersed the food in hot oil with a contact among oil, air and
food at a high temperature of 150 to 190 °C [3]; [4]. Frying is used especially for the production
of fast foods. A wide range of fried food products have been developed over the years, which
include chicken and fish products, doughnuts, snack foods such as potato crisps and chips, and
many other products based on corn, rice, plantain, sweet potato and wheat. These fried foods
are far more appreciated by consumers because of desirable attributes they contain such as
typical appealing flavor, golden brown color, and a crisp texture [5]. This can be observed from
the rapidly increasing number of fast food restaurants and vendors in the last few decades [6].
During continuously and/or repeatedly frying of food in the same oil, the elevated temperature,
continuous exposure to oxygen and the presence of moisture from the food [7]; [8]; [9] results
in several chemical reactions such as oxidation, hydrolysis, isomerization, cyclization, and
polymerization [3]; [10]. These reactions are responsible of the formation of undesirable
volatile and non-volatile compounds (aldehydes, ketones, etc.). Most of the Volatile compounds
are lost from hot frying oil, while non-volatile compounds steadily increase and, are retained in
the frying oil and in the fried product [11]; [12]. Others compounds include monomers, dimers
and oxidized polymers, non-polar dimers and polymers, trans isomers of fatty acids, FFA,
mono- and diglycerides are also formed by hydrolysis and oxidation of triglycerides in the oil
during heating or frying process. However, some of these all compounds are potentially toxic
with important repercussions on health [13]; [1], among which include heart disease,
diabetes, cancer, and stroke. The frying medium also undergoes very sensory and physical
properties changes and finally of the food to be fried. Indeed, the amounts and accumulate of
these undesirable compounds formed in fatty medium, depend not only on the high
temperature, moisture and oxygen availability but also on among others parameters such as
the type of oil and food [6], the frying conditions, and the food/oil ratio [7], replenishment of
fresh oil [14], original oil quality, food materials and fryer type [3].
The modifications of heated oils in absence of food, or used in frying experiments, has been the
subject of several studies in recent years [15]; [16]; [17]. Majority of these studies are based
on the determination of physical and/or chemical parameters, such as FFA, TPC, crystallization
peak, polymers of triglycerides, oxidised triglycerides, dimmers, viscosity, IV, CD values,
peroxide and anisidine values as well color tests. These tests are extensively used; however
they are not decisive in themselves with regard to the physical parameters. Color, a physic
parameter for example, basically depends on the sort of food fried as well as the oil [18]. The
percentage of TPC and FFA are the most predominant indicators for oil quality [4]; [6]. Several
countries have adopted recommendations or legal limits to discard frying oil when the FFA
reaches 1.0% [11] and the percentage of TPC becomes higher than 24-25% [12].
Different oils (of both animal and vegetable origin) may be used for frying of foods. Vegetables
oils, such as palm oil and their fractions, olive oils (extra virgin, virgin, or just “olive oil”),
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European Journal of Applied Sciences (EJAS) Vol. 10, Issue 5, October-2022
Services for Science and Education – United Kingdom
sunflower oil, soybean oil, corn oil, peanuts oil, ect... are common frying medium and are used
extensively, both domestically and on a commercial scale. Each vegetable oil is characterized
by a typical stability against oxidation [10] and hydrolysis reactions which occur during frying.
Their stability depends on the fatty acid composition and composition of minor compounds
with a natural powerful antioxidant activity [17]. Therefore, oxidative stability of the deep- frying medium is a critical criterion for the selection of the frying oils. Prompting has led to
several modifications to the fatty acid composition of edible oils, usually by decreasing the
contribution of linoleic and linolenic acids and increasing that of oleic acid [19]. In addition, this
type of oils are characterized by a high nutritional value, because today, oleic acid is of a certain
importance from a nutritional point of view because this monounsaturated fatty acid lowers
LDL, while increasing HDL according to Matthäus [20]. Previous studies have proven that the
choice of partially hydrogenated oils, of oils with fatty acid modification and blending oils from
more saturated or monosaturated oils to reduce the amount of polyunsaturated fatty acids offer
better resistance to thermo-oxidative degradation. In the majority of studies, oils content high
percentage of oleic acid are reported as the betters oils compared to regular oils due to its good
thermal and oxidative stability during traditional frying as shown by the research work of [19];
[21]; [4].
Soybean oil (SBO), refined, bleached and deodorized (RBD) palm and palm olein oils are
commonly used in deep-frying in many tropical countries of central Africa such as Republic of
Congo for commercial and domestic purposes. The problem in these countries is often non- compliance with good cooking practices. Another one additional problem is the prolonged use
of old oils that may contain toxic compounds and which can seriously affect the safety of
consumer by consuming the foods fried in these oils. Indeed in these countries, in most cases,
frying oil degradation is evaluated based on visual inspection wherein for instance the restorer
or merchant experience to decide when to discard the oil for example based on excessive
foaming, odor, smoking, color changes, and by tasting the food products. Unfortunately, these
are not reliable methods due to their subjective nature and these parameters may manifest only
when the oil has already become unsafe to be reused [18].
In France, Lesieur food manufacture, has developed a super stable frying oil to bypass the
problems associated with the duration of the stability of frying oils. This oil, under the name
Frial is formulated from the mixture of high oleic sunflower oil, rapeseed oil, and grape pips oil.
These mixture confer to Frial oil (FO) a good organoleptic characteristics (aroma and taste), but
also potential health benefits.
Therefore, the purpose of this study was to evaluate the stability of RBDPOo and SBO during
repeated discontinuous deep-fat frying of ripe plantain (a climacteric fruit, which is largely
cultivated and consumed in Congo and in other many tropical countries of the world),
comparing it with the use of FO, evaluating the effect of the deteriorative changes on the final
oils. The reason to study these oils is because they have different composition
(monounsaturated/saturated fatty acid (MUFA/SFA)) ratios, that the degradation of the oils is
certainly done in different way and to propose the limits to use the unsafe oils based on
percentage of TPC and FFA.
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Pambou-tobi, N. P. G., Sompila, A. W. G. T., Niamayoua, R. K., & Linder, M. (2022). Comparative Study on Frying Performance of Three Different
Oils for the Preparation of Ripe Plantain Banana. European Journal of Applied Sciences, 10(5). 94-113.
URL: http://dx.doi.org/10.14738/aivp.105.13045
MATERIALS AND METHODS
Oils samples
The oils chosen for this study were Refined-bleached-deodorized Palm olein (RBDPO), soybean
oil (SBO) and Frial oil (FO). All three were purchased at a local store.
Preparation of raw plantain samples
Plantains (Musa paradisiaca AAB, a triploid of seedless Musa balbisiana and Musa acuminate)
variety “Harton” were purchased in a local market (Nancy, France) and used at a maturity index
of 7 (entirely yellow with brown spots). The peeled plantains were about 19-34 cm long and
the diameter was comprised in the range of 3.8-5.5 cm. Before the frying step, ripe plantains
were manually peeled and then cut into uniform discs using a domestic electric slicer (SEB,
France). Samples were cut into discs using a punch (30 mm diameter and 10 mm thicknesses
and 8.95 g of average weight).
Chemicals reagents and standards
Petroleum ether (purity ≥99), diethyl ether (purity ≥99), methanol (purity = 99%), chloroform
(purity = 99%), hexane (purity = 97%), ethanol (purity = 99%), 2,2,4-trimethylpentane
(99.5%), glacial acetic acid (purity = 99-100%) were the solvents used for separated the total
polar compounds and fatty acid by CPG, determined CD, FFA, PV, IV and p-AV. Majority of
solvents were purchased from Sigma–Aldrich (France). P-anisidine reagent (purity ≥ 99), silica
gel (typ 10184 70-230 mesh, 100Å), cyclohexane (purity ≥ 99) and others chemicals were used
as analytical grade.
Frying experiments
An electric deep fat fryer (Filtra ® one, Model No. F52-1, dimensions 34 x 33 x 26 cm, SEB,
France) with 2.1 L or 1.89 Kg capacity was filled with 2 L of oil for every batch of experiments.
At the start of every day, oil was heated up for 30 mn at 170–175 °C. Kinetics of oil temperature
was measured with a digital thermometer attached to a steel probe model Almemo 2290-4 V5
AMR (Ahlborn Meß-und Regelungstechnik, GmbH, series H02030452M). This thermometer
was connected to a computer through a data acquisition software program for recording the oil
bath temperature. After the initial heating up process, the first frying cycle was started.
Subsequent frying cycles were performed at an interval of fifteen minutes. During each frying
cycle, 180g slices of ripe plantain were fried with plantain to oil ratio was kept same at 0.09
(w/v) (g/ml)). Each day, the oil was heated for 4 h in total, with 17 frying cycles performed. The
oil was used continuously for 10 days with any replenishment of fresh oil to maintain a constant
volume [22]. This amounted to a total of 170 frying cycles performed for each batch of oil. Oil
samples were collected each day in 125 mL of standard plastic box, flushed with nitrogen and
then stored at 4°C in the dark to prevent further oxidation before further analysis.
Three frying batches were prepared for the three different oils respectively and are denoted as
Palm olein (RBDPO), soybean oil (SO) and Frial oil (FO).
Analytical methods
Color measurement
Color of oil was measured with a Lovibond Tintometer Model PFX 195, using an oil sample of 5
ml. The oil samples were analyzed at 45°C according to Bhattacharya [23] procedure. The