International Journal of Cosmetic Science, 2015, 37, 82 91 doi: 10.1111/ics.12173
Enzymatically interesterified fats based on mutton tallow and
walnut oil suitable for cosmetic emulsions
M. Kowalska*, M. Mendrycka*, A. Zbikowska and S. Stawarz*
*Faculty of Material Science, Technology and Design, Kazimierz Pulaski University of Technology and Humanities, Chrobrego Street 27, 26-600

Radom, and Department of Food Technology, Faculty of Food Sciences, Warsaw University of Life Sciences (WULS-SGGW), Nowoursynowska
159C, 02-787 Warsaw, Poland
Received 26 August 2014, Accepted 7 October 2014
Keywords: emulsions, interesterification synthesis, mutton tallow, sensory evaluation, stability of emulsion, walnut oil
Synopsis was added to the enzymatic preparation, exhibited the best sensory
OBJECTIVE: Formation of emulsion systems based on interesteri- profile.
fied fats was the objective of the study. Enzymatic interesterifica-
tion was carried out between enzymatic mutton tallow and
Resume
walnut oil in the proportions 2 : 3 (w/w) to produce fats not
OBJECTIF: La formation des syst emes d emulsion a base de lipides
available in nature. At the beginning of the interesterification
transest erifi es etait l objectif de l etude. L est erification enzymatique
process, the balance between the interesterification and fat
a et e r ealis ee entre le suif de mouton et l huile de noix dans les pro-
hydrolysis was intentionally disturbed by adding more water to
portions 2: 3 (poids / poids) pour produire des lipides qui ne sont
the catalyst (Lipozyme IR MR) of the reaction to produce more
pas disponibles dans la nature. Au d ebut du processus de trans-
of the polar fraction monoacylglycerols [MAGs] and diacylglyce-
est erification, l equilibre entre la transest erification et l hydrolys e
rols [DAGs]. To obtain a greater quantity of MAGs and DAGs in
des lipides a et e volontairement perturb ee par l ajout d eau pour le
the reaction environment via hydrolysis, water was added (11,
catalyseur (Lipozyme IR MR) de la r eaction en vue de produire
13, 14, 16 w-%) to the enzymatic preparation. The obtained fats
davantage de fractions polaires monoacylglyc erols [MAG] et diacyl-
were used to form emulsions.
glyc erols (DAG). Pour obtenir une plus grande quantit e de MAG et
METHODS: The emulsions were evaluated with respect to sensory
de DAG dans le milieu de r eaction par hydrolyse, de l eau a et e
and skin moisturizing properties by 83 respondents. Determination
ajout ee (11, 13, 14, 16% en poids) de la pr eparation enzymatique.
of emulsion stability using temperature and centrifugal tests was
Les corps gras obtenus ont et e utilis es pour former des emulsions.
carried out. Morphology and the type of emulsions were deter-
METHODES: Les emulsions ont et e evalu ees par rapport aux pro-
mined.
pri et es hydratantes et sensorielles par 83 r epondants. La d etermina-
RESULTS: The respondents described the skin to which the emul-
tion de la stabilit e de l emulsion en fonction de la temp erature et
sions in testing were applied as smooth, pleasant to touch and ade-
les essais d etalement ont et e effectu es. La morphologie et le type
quately moisturized.
d emulsions ont et e d etermin es.
CONCLUSIONS: The work has demonstrated that interesterifica-
RESULTATS: Les volontaires ont d ecrit la peau sur laquelle les
tion of a mutton tallow and walnut oil blend resulted in new fats
emulsions des tests ont et e appliqu ees comme lisse, agr eable au
with very interesting characteristics of triacylglycerols that are not
toucher et hydrat ee convenablement.
present in the environment. The results of the present work indi-
CONCLUSIONS: Le travail a d emontr e que l est erification d un
cate the possibility of application of fats with the largest quantity of
m elange d huile de suif de mouton et de l huile de noix aboutit a
MAGs and DAGs as a fat base of emulsions in the cosmetic indus-
de nouvelles lipides avec des caract eristiques tr es int eressantes de
tries. The hypothesis assumed in this work of producing additional
triglyc erides qui ne sont pas pr esents dans l environnement. Les
quantities of MAGs and DAGs (in the process of enzymatic inter-
r esultats de la pr esente etude indiquent la possibilit e de l applica-
esterification) responsible for the stability of the system was con-
tion de lipides avec des plus grandes quantit es de MAG et DAG
firmed. It should be pointed out that the emulsions based on
comme base de lipide d emulsions dans les industries cosm etiques.
interesterified fats exhibited a greater level of moisturization of the
L hypoth ese suppos ee de ce travail, a savoir de produire des quan-
skin than the emulsions containing non-interesterified fat. Also, in
tit es suppl ementaires de DAG et MAG (dans le processus d inter-
the respondents opinion, the emulsion containing fat, which was
est erification enzymatique) responsables de la stabilit e du syst eme a
modified during enzymatic interesterification when 13% of water
et e confirm ee. Il convient de souligner que les emulsions a base de
graisses inter-est erifi ees pr esentaient un plus grand niveau d hydra-
tation de la peau que les emulsions contenant des mati eres grasses
non-est erifi ees. Aussi, de l avis des r epondants, l emulsion conten-
Correspondence: Malgorzata Kowalska, Faculty of Material Science, ant de la graisse qui a et e modifi ee au cours de transest erification
Technology and Design, Kazimierz Pulaski University of Technology
enzymatique quand 13% de l eau a et e ajout ee a la pr eparation
and Humanities, Chrobrego Street 27, 26-600 Radom, Poland. Tel.:
enzymatique, pr esentait le meilleur profil sensoriel.
[phone]; fax: [phone]; e-mail: [e-mail]
82 © 2014 Society of Cosmetic Scientists and the Soci et e Francaise de Cosm etologie
ß
Interestrified fats suitable for cosmetic emulsions M. Kowalska et al.
as substrates during interesterification. The obtained new fats with
Introduction
interesting characteristics were used as a fat base in the proposed
Emulsions are unquestionably among the most important of all the cosmetic emulsions. Moisturizing and sensory properties of the syn-
colloid and macrodispersed systems, not only from a commercial thesized emulsions were studied by the techniques below.
point of view, but also due to their great scientific interest [1]. They The novelty in this study was the application of interesterified
are used in the food, pharmaceutical, petrochemical and cosmetic fats as the fatty base in cosmetic emulsions. Fats of this type have
industries [2 6]. In the food industry, emulsions have the following mainly been used by the food industry before.
applications: low-calorie products, improved sensory characteristics
and taste masking. In the pharmaceutical field, emulsions are used
Materials and methods
as drug delivery systems. In the cosmetic industry, they are used as
easily spreadable creams with encapsulated ingredients in both
Materials
water and oil phases [7].
Emulsions are dispersed, multiphase systems consisting of at Walnut oil (WO) was purchased at a local market. The composition
least two insoluble liquids. The two immiscible phases are usually of walnut oil s fatty acids was as follows: C16:0 (7.3%), C16:1
oil and water. The dispersed phase is present in the form of droplets (0.2%), C 18:0 (2.5%), C 18:1 cis 9 (19.8%), C 18:2 n-6 (58.0%),
in a continuous phase. Depending on the emulsification process, C 18:3 n-3 (12.3%).
the diameter of the spherical droplets is between 0.1 lm and Mutton tallow (L) was laboratory-refined, bleached and deodor-
0.1 mm. Emulsions of this kind are thermodynamically unstable, ized under a vacuum at 105°C. Its main fatty acid composition was
which means that there is a tendency to reduce the interface, caus- as follows: C 14:0 (1.8%), C 16:0 (18.4%), C 16:1 cis 9 (0.8%),
ing the droplets to coalesce and thus reducing the total amount of C17:0 (1.9%), C 18:0 (29.2%), C 18:1 cis 9 (31.6%), C 18:2 all cis
interface [7]. There are mainly two types of emulsions: oil-in-water (1.7%), C18:2 cis-9, trans-11 (0.8%), C 18:3 all cis (0.6%), C 20:0
(o/w), and water-in-oil (w/o). However, recently, there has been (0.3%), C 20:1 cis 11 (0.1%), total saturated FA (SFA) (52.0%), total
increasing interest in the development of multiple or double emul- monounsaturated FA (MUFA cis) (34.1%), total polyunsaturated FA
sions, for example water-in-oil-in-water (W/O/W) and oil-in-water- (PUFA cis) (2.2%), total n-3 (0.6%) and total n-6 (1.6%).
in-oil (O/W/O). For example, W/O/W emulsions consist of small As a biocatalyst during enzymatic interesterification, Lipozyme
water droplets dispersed in larger oil globules, which are them- RM IM (Novozymes, Bagsvaerd, Denmark) was used. The commer-
selves dispersed in an aqueous continuous phase. Double emulsions cial Lipozyme RM IM preparation contains immobilized lipase from
present many interesting possibilities for the controlled release of Rhizomucor miehei and contains 4 w-% of water. Activity of Lipo-
chemical substances initially entrapped in the internal droplets, zyme RM IM is 5 6 BAUN/g.
which can have a significant role in the food industry (low-calorie Carboxymethylcellulose was obtained from Mikro-Technik GmbH
Ź
products, improved sensory characteristics, taste masking), cos- & Co. KG, Burgstadt, Germany. It was used as a thickener for
metic industry (easily spreadable creams with encapsulated ingredi- emulsion solutions.
ents in both water and oil phases), pharmaceutical industry (drug Sunflower lecithin was obtained from Lasenor Emul, S.L. Barce-
delivery systems) and other fields such as agriculture and the lona, Spain. It was used as an emulsifier.
production of multicompartment microspheres [8, 9].
Kinetically stable emulsions can be formed by adding emulsifiers
Methods
and/or thickening agents (proteins and hydrocolloids) to overcome
the activation energy of the system [10 12]. The conventional Enzymatic interesterification of fats
explanation for emulsion stabilization by such agents is their accu- The process of interesterification was carried out according to our
mulation at the oil water interface in the form of a densely packed own specifications and previous experience [2, 15, 16].
layer, which may prevent droplet flocculation and coalescence by a Mutton tallow was mixed at 70°C under nitrogen with walnut
steric mechanism [12, 13]. oil (L : WO) in the proportions 2 : 3 (w/w). Flasks containing fat
Monoacylglycerols and their derivatives have wide application as blends were placed in a thermostated mineral oil shaker bath (type
emulsifiers in the food, pharmaceutical and cosmetic industries. 357, producer Elpin plus, Lubawa, Poland). After thermal equili-
Acylglycerol emulsifiers (mainly employed as W/O stabilizers) are bration of the fat blend at the desired temperature of 60°C, 8 w-%
used in food in all countries, because they contain components of Lipozyme RM IM was added to the blend. To obtain a greater
which can be metabolized. Their identity with natural lipid struc- quantity (MAGs and DAGs  polar fraction responsible for good sta-
tures results in very favourable ecological properties. These deriva- bility of emulsions) in the reaction environment via hydrolysis,
tives are obtained by the glycerolysis of triacylglycerols or by the water was added (11, 13, 14 and 16 w-%) to the enzymatic prepa-
direct esterification of glycerol with fatty acids [14]. ration. That quantity of MAGs and DAGs was desired because
The aim of this work was to assess new formulations (emulsions) those fats with a higher quantity of the polar fraction are used in
containing interesterified fats. First, the new fats were formed via emulsion systems as natural emulsifiers. The interesterification was
enzymatic modification, then those fats were put into emulsions as performed with continuous shaking for 6 h. After a predetermined
a fat base of the emulsions. On the basis of previously conducted time of interesterification, the samples were filtered to stop the
studies on chemical and enzymatic interesterification of fats such reaction.
as beef tallow and fractions of vegetable oils, it is known that The composition of fatty acids (FA) of walnut oil and mutton tal-
fats with a unique structure can be obtained by interesterification low was determined using gas chromatography (GC) after conver-
[15 17]. Using enzymatic interesterification, hard fats can be sion of the fats to fatty acid methyl esters (FAMEs). They were
enriched in monoenoic fatty acids, or polyenic fatty acids from oils analysed using a Hewlett Packard model HP 6890 gas chromato-
[16 18]. For this purpose, vegetable oil (such as walnut oil) rich in graph with HP-88 capillary column (88% cyanopropyl aryl-poly-
unsaturated fatty acids and mutton tallow as a hard fat were used siloxane, 100 m 9 0.25 mm 9 0.25 lm film thickness from
© 2014 Society of Cosmetic Scientists and the Soci et e Francaise de Cosm etologie 83
ß
International Journal of Cosmetic Science, 37, 82 91
Interestrified fats suitable for cosmetic emulsions M. Kowalska et al.
Table I Composition and parameters of emulsions
Technology and Humanities in Radom, Poland. The remaining
women represented the profession of pharmacy technician.
Research was conducted under the control of a trained person who
Type of emulsion
helped during the whole period of the research. Research for all
volunteers lasted for 6 weeks (17 February 2014 to 30 March
Component [%] E I E II E III E IV E V E VI 2014). The effect of the cosmetic emulsions produced on humidifi-
cation of cuticular cornea was evaluated. Testing began on clean,
degreased skin, which constituted the point of reference and zero
Sunflower lecitin 5.0 5.0 0 0 0 0
time of the cosmetic effect on the skin. Approximately 0.01 g of
Content of polar 3a 14b 23c 26d 27d 32e*
the emulsion was then applied to the same 20 9 20 mm fragment
fraction(MAGs, DAGs, FFA)
of the forearm skin and left there for 5 min. The probe of the cor-
Carboxymethyl-cellulose 1.0
Fat Blend 30.0
nea before and after the measurement was always wiped with a
Sodium benzoate 0.20
clean cotton cosmetic swab. The region of the skin before and after
Water Up to 100%
each measurement was wiped with a clean, dry cotton cosmetic
Parameter
swab too. Humidification was measured at 22 1°C after 5 min
Mixing speed, [RFC] 38 332
and at intervals of 15 min until 90 min after the moment the skin
Mixing time, minutes 4
was cleaned of the emulsion. Variations of skin humidification were
calculated by a formula, averaging results for all subjects involved
Legendary: E I: Emulsion containing initial blend (L : WO; 2 : 3, w/w)  non-in-
in the test:
teresterified blend of fats; E II: Emulsion containing fat blend (L : WO; 2 : 3, w/
Nt NPKt
w) interesterified by Lipozyme IM containing 4% water in the enzymatic prepara-
ZNt ź 100%;
tion; E III: Emulsion containing fat blend (L : WO; 2 : 3, w/w) interesterified by
NPKt
Lipozyme IM containing 11% water in the enzymatic preparation; E IV: Emulsion
containing fat blend (L : WO; 2 : 3, w/w) interesterified by Lipozyme IM contain- where, ZNt is change of skin humidification over time  t ; Nt is
ing 13% water in the enzymatic preparation; E V: Emulsion containing fat blend
average skin humidification after  t for a place with the tested cos-
(L : WO; 2 : 3, w/w) interesterified by Lipozyme IM containing 14% water in the
metic on; NPKt is average skin humidification after  t for the con-
enzymatic preparation; E VI: Emulsion containing fat blend (L : WO; 2 : 3, w/w)
trol point.
interesterified by Lipozyme IM containing 16% water in the enzymatic prepara-
tion. Different letter in lines indicate mean values that differ statistically signifi-
cantly (p<0.05).
Sensory determination
Consumer testing continued for 2 weeks in the period 02 to
Agilent). The temperature of the injector was 280°C and of the 16 March 2014 and was conducted three times a week. Therefore,
flame ionization detector (FID) 290°C. The temperature of the col- the volunteers (83 females) were able to use the emulsions several
umn was in the range from 60 to 230°C, at 4°C min 1. The flow times before the final evaluation. Six cosmetic emulsions were
rate of carrier gas was 1.2 mL min 1. Helium was used as the car- subjected to the sensory analysis. Five emulsions contained inter-
rier gas. Identification of the fatty acids was carried out by compar- esterified fats, and the reference emulsion was a mix of non-inter-
ison of the retention times with a standard mixture of fatty acid esterified fats (Table I). The emulsions were assessed for the
methyl esters. GC of the FAMEs was performed according to the following characteristics: consistency (density and cohesion of the
ISO standard. tested cosmetic), homogeneity (behaviour of the preparation when
Polar fraction content was determined using a column chroma- applied to the skin  absence of clots or air bubbles), cushion effect
tography on silica gel, SG 60, 70 230 mesh, Merck, Darmstadt, (palpability of the substance when rubbed between fingers), distri-
Germany, according to the ISO standard [19]. bution (facility of spreading on the skin surface), smoothing
(smoothing effect when applied to the skin), viscosity (degree of pal-
pable viscosity left on the skin), greasiness (a fat film remaining on
Emulsion preparation and analysis
the skin) and absorption (rate of absorption by the skin). Each
Emulsions were prepared according to the specifications shown in characteristic was graded on a scale of 1 5, with 1 the minimum
Table I. They were prepared in the same way by adding together and 5 the maximum score. For ease of organoleptic testing, each
the water with thickener and the fat phase and stirring with the survey was enclosed with guidelines for sensory analysis (Table II)
mixer RW 20 DZM (by Janke & Kunkel, Staufen im Breisgau, Ger- describing the test procedure and the scoring scale [23, 24].
many) for 4 min with the velocity of 38 332 relative centrifugal Sensory analyses were conducted in the presence of the person
force (RCF). Emulsions were prepared at room temperature (22°C). responsible for sensory assessment (proper behaviour during mea-
The volume of each mixtures was 100 g. surements). In addition, the survey was supplemented with a ques-
tion concerning the selection of the emulsion, which was the most
suitable for the respondents.
Determination of skin humidification
Skin humidification was measured by means of a CM 825 Corne-
Determination of emulsion stability using the centrifugal test
ometer by Courage+Khazaka Electronic [20, 21]. Respondents gave
their written consent for taking measurements of functional param- Determination was measured in the centrifugal machine at
eters of the skin before starting the study. Testing was carried out 1008 RCF. Test tubes were filled with 15 mL of the emulsion and
on 83 women aged 30 45. To have valid calculation, the reading then centrifuged for 30 min, with the state of emulsion checked
of skin humidification was taken five times. Some of the women every 10 min. If the emulsion remained homogeneous after
were educated cosmetology graduates from the University of 30 min, it was considered to have proper stability.
84 © 2014 Society of Cosmetic Scientists and the Soci et e Francaise de Cosm etologie
ß
International Journal of Cosmetic Science, 37, 82 91
Interestrified fats suitable for cosmetic emulsions M. Kowalska et al.
Table II Guidelines for sensory analysis of the cosmetic emulsions tested (study based on literature [22, 23] and own experience)
Feature Description of test procedure Score (1 5)
C Position hand at an angle of 60° and place 5 cm3 of the 5. Cosmetic is easy to apply, not flowing
test substance there. Proceed to analyse its consistency by 4. Easy to apply yet flowing can be observed
assessing the ability to keep the cosmetic adhering to the 3. Cosmetic is hard to apply
hand. 2. Too thick to apply to the hand
1. Impossible to apply
H Spread the substance on your hand and assess 5. Completely homogeneous, no clots or air bubbles, forms a smooth layer on the
smoothness of its layer, presence of clots or air bubbles. skin when applied
4. Homogeneous, no clots and few air bubbles, forms an uneven layer
3. Observable and palpable clots and air bubbles in the substance and on the
skin when applied
2. Heterogeneous
1. Formulation components are not dissolved.
CE Scoop 0.5 cm3 of the emulsion and rub between the thumb 5. Imperceptible substance
and index finger. 4. Weakly perceptible substance
3. Somewhat perceptible substance
2. More perceptible substance
1. Highly perceptible substance
D Spread 0.5 cm3 of the preparation on the forearm skin 5. No resistance to spreading
and observe its resistance to spreading. 4. Little resistance to spreading
3. Incomplete cover, good spreading
2. Difficult to spread
1. Impossible to spread
SM Apply 0.5 cm3 of the emulsion on the cleaned forearm 5. Very smooth, soft skin surface
skin and after an hour appraise the skin s smoothness 4. Smoother and softer skin surface than of the reference standard
in reference to a standard to which the substance has 3. The skin surface is as smooth as that of the reference standard
not been applied. 2. Rough skin
1. Very rough skin
ST Apply and spread the emulsion on the cleaned forearm 5. No palpable skin viscosity
skin, then press the other hand against this skin section 4. Low skin viscosity
and assess viscosity. 3. Palpable skin viscosity
2. Increased skin viscosity
1. High skin viscosity
G Apply 0.5 cm3 of the substance on the cleaned forearm 5. No sense of grease or film formation on the skin after application
skin and assess formation of a greasy film. 4. Weak sense of greasiness, no film on the skin
3. Thin, greasy film on the skin after application
2. Greasy film on the skin directly on application
1. A compact, greasy film after application
A Apply the substance on cleaned skin and assess the time 5. Very good absorption below 30 s
of its absorption. 4. Good absorption from 30 s to 1 min
3. Average absorption from 1 to 3 min
2. Poor absorption from 3 to 5 min
1. Very poor absorption for more than 5 min
C, Consistency; H, Homogeneity; CE, Cushion effect; D, Distribution; SM, Smoothing; ST, Stickiness; G, Greasiness; A, Absorption.
ried out 48 h from the emulsion manufacturing. The measure-
Determination of emulsion stability using the temperature test at
ments were taken three times.
35 and 3°C
All emulsions were stored in the dryer at 35°C ( 0.3°C) and in the
Viscosity examination
refrigerator at 3 5°C alternately for 5 days, with a change every
24 h. If the emulsion remained homogeneous in such conditions, it The viscosities of the samples were determined at 25°C using spin-
was considered to have proper stability. dle no. 1 and no. 2 in a Brookfield Rheometer DV-I+ 48 h after
their production.
Determination of mean particle size and particle size distribution of
fat emulsions Determination of type of emulsion
Determination was carried out in the range 0.12 704.0 lm by Conductivity of determined emulsions was measured by microcom-
laser scattering using a Microtrac Particle Size Analyzer (Leeds & puter pH/conductivity meter CPC-551 ELMETRON with chloride
Northrup, Philadelphia, U.S.A.) after preparation. The emulsions electrode EClL-305W EUROSENSOR-GLIWICE, Poland. Conductivity
were diluted 1 : 200 with distilled water. Determination was car- of the all tested emulsions was determined.
© 2014 Society of Cosmetic Scientists and the Soci et e Francaise de Cosm etologie 85
ß
International Journal of Cosmetic Science, 37, 82 91
Interestrified fats suitable for cosmetic emulsions M. Kowalska et al.
P < 0.05 was considered significant. STATGRAPHICS plus 4.0 package
Morphology of emulsions
(Statistical Graphics Corp., Warrenton, VA, U.S.A.) was used.
Optical microscopic observation of the emulsions was done using a
usual optical microscope (Nikon  Polska, production PZO, lens
Results and discussion
Nikon 4 4/0.10 (160/-WD 25), ocular Nikon China CF WE 15/12,
camera Panasonic type GP-KR 222, software MICROSCAN for Win- Analysing the interesterification process, it was found that new a-
dows). An appropriate amount of freshly prepared emulsion was cylglycerols were formed. Generally, FFA, MAG and DAG contents
placed onto the microscopic slide. A cover slip was placed on the sam- increased compared to the starting blend. The highest value for
ple, ensuring that no air or bubbles were trapped between the sample MAG and DAG contents was observed for the fat blend interesteri-
and cover slip, and the samples were tested with a 409 objective. fied by Lipozyme RM IM with 16% water in the enzymatic prepara-
tion (Table I). Consequently, addition of water to the enzymatic
preparation generated a greater quantity of the polar fraction in
Statistical analysis
the interesterified blends. Appearance of MAGs and DAGs during
The results were subjected to one-way ANOVA. The Duncan test interesterification is very important because they are seen as good
was used to assess the differences between means. The level of emulsifiers [14].
Figure 1 Changes of the hydration degree of the skin with the passage of time. Legendary: E I: Emulsion containing initial blend (L : WO; 2 : 3, w/w)  non-
interesterified blend of fats; E II: Emulsion containing fat blend (L : WO; 2 : 3, w/w) interesterified by Lipozyme IM containing 4% water in the enzymatic prep-
aration; E III: Emulsion containing fat blend (L : WO; 2 : 3, w/w) interesterified by Lipozyme IM containing 11% water in the enzymatic preparation; E IV:
Emulsion containing fat blend (L : WO; 2 : 3, w/w) interesterified by Lipozyme IM containing 13% water in the enzymatic preparation; E V: Emulsion contain-
ing fat blend (L : WO; 2 : 3, w/w) interesterified by Lipozyme IM containing 14% water in the enzymatic preparation; E VI: Emulsion containing fat blend
(L : WO; 2 : 3, w/w) interesterified by Lipozyme IM containing 16% water in the enzymatic preparation.
Table III Mean values of sensory assessment obtained as a result of the survey
Type of emulsion*
Feature EI EII E III EIV E V E VI
C 5.0 0.75 4.8 0.093 4.3 0.27 4.5 0.35 4.3 0.37 4.5 0.34
H 5.0 0.121 5.0 0.87 5.0 0.89 4.8 0.27 5.0 0.45 5.0 0.26
CE 5.0 0.71 4.8 0.23 4.8 0.64 4.8 0.64 4.2 0.74 4.8 0.47
D 5.0 1.17 5.0 0.28 5.0 0.26 5.0 0.1.02 5.0 0.28 4.7 0.36
SM 5.0 1.02 5.0 0.73 5.0 0.34 5.0 0.74 5.0 0.54 5.0 0.65
ST 4.5 1.04 4.0 0.63 5.0 1.02 4.8 0.27 4.7 0.48 4.5 0.50
G 4.0 0.82 4.8 0.81 4.3 0.24 4.5 0.47 4.5 0.50 4.3 0.26
A 4.0 0.76 4.5 0.27 4.3 0.54 4.7 0.38 4.8 0.93 4.5 0.34
C, Consistency; H, Homogeneity; CE, Cushion effect; D, Distribution; SM, Smoothing; ST, Stickiness; G, Greasiness; A, Absorption.
*See legends of E I to E VI is given in Table I.
86 © 2014 Society of Cosmetic Scientists and the Soci et e Francaise de Cosm etologie
ß
International Journal of Cosmetic Science, 37, 82 91
Interestrified fats suitable for cosmetic emulsions M. Kowalska et al.
Skin care formulations, that is cosmetic and dermal products, VI (Fig. 1). Emulsions IV and V exhibited somewhat lower values in
form a distinctive group among emulsions, because they must meet the range 50 60%. Application of emulsion II generated minimum
a whole series of requirements. They must have a pleasing appear- humidification, whereas skin covered with emulsions I and III dis-
ance and retain it during storage, give an agreeable feeling during played a relatively high degree of humidification, that is, nearly
application and, most importantly, provide long-term beneficial 60%, five minutes after application. It can be assumed that the
effects to the skin [25]. It is important that cosmetic emulsion-type greater amount of natural emulsifiers in the emulsion could influ-
topical products must provide skin hydration in both healthy and ence the higher degree of skin humidification. It seems that their
diseased conditions [26]. presence in the emulsion is desirable due not only to their stabilizing
Assays of humidification properties of the emulsions found the properties but also their humidification properties. The humidifica-
greatest average humidification (63%) on application of emulsion tion was observed to decline after successive intervals, however, to
Figure 2 Sensory profile of emulsions E I to E VI. See legends of E I to E VI is given in Fig. 1.
© 2014 Society of Cosmetic Scientists and the Soci et e Francaise de Cosm etologie 87
ß
International Journal of Cosmetic Science, 37, 82 91
Interestrified fats suitable for cosmetic emulsions M. Kowalska et al.
reach 30 40% after 90 min (Fig. 1). The degree of skin humidifica-  the spider web . According to presented data, it appears that emul-
tion was clearly at a minimum after application of emulsion II. sion IV had a sufficient amount of natural emulsifiers which stabi-
Results of the sensory evaluation are presented in Table III. Accord- lized this emulsion, and, simultaneously, the emulsion was
ing to the results shown in Table III and Fig. 2, emulsion E IV had considered the best in terms of sensory properties. Additional emul-
optimal properties. The field formed by its average assessments most sifiers present in emulsion VI increased the moisturizing properties
closely approximates  the spider web , whereas the mean evalua- but did not increase the explanatory sensory emulsion.
tions generated for emulsion E1 create a field the most distant from It can be said that the respondents most highly valued the
following parameters: smoothing, homogeneity and spreading.
Their mean values were 5.0, 4.96 and 4.96 points, respectively.
Greasiness and skin absorption were rated the lowest, on the other
hand (4.37, 4.46 points).
Choice of an emulsion for everyday use was one of the questions
in the survey. Responses are illustrated in Fig. 3. It is clear that
most respondents (33%) chose emulsion IV for everyday skin care.
In the respondents opinion, this emulsion displayed characteristics
similar to those of the remaining substances, yet the skin was less
shiny than in the case of other emulsions.
According to the type, all tested emulsions were o/w emulsions.
After immersing the electrode in a drop of emulsion, one observed
deviation of the amperometer indicator, which confirmed the con-
ductivity of these layouts (Fig. 4). It was also confirmed by the
Figure 3 Percentage of people reporting the daily use of the emulsion. See
digestion test of emulsion drops in water. All emulsions in a few
legends of E I to E VI is given in Fig. 1.
Figure 4 Conductivity of studied emulsions 48 h after production. See legends of E I to E VI given is in Fig. 1.
Figure 5 Percentage of particles of given sizes and accumulated distribution in the emulsion: E I to E VI 48 h after production. See legends of E I to E VI is
given in Fig. 1.
88 © 2014 Society of Cosmetic Scientists and the Soci et e Francaise de Cosm etologie
ß
International Journal of Cosmetic Science, 37, 82 91
Interestrified fats suitable for cosmetic emulsions M. Kowalska et al.
Figure 6 Average partice sie and viscosity of emulsion: E I to E VI 48 h after production. *Values of viscosity 9102. a,b,c: Different letters indicate mean val-
ues that differ statistically significantly (P < 0.05). See legends of E I to E VI is given in Fig. 1.
Figure 7 Optical microscopic image of fresh emulsions E I  E VI. See legends of E I to E VI is given in Fig. 1.
minutes were solubilized in the water. It is believed that o/w emul- Remaining emulsions (IV, V, VI) retained the proper form to the
sions generally show a fairly high rate of penetration into the skin, end of test.
are less greasy and form a protective film on the skin [5]. According to authors [3], macroemulsions are emulsion systems
Generally, the temperature test was passed successfully by all with droplet sizes ranging from 0.1 to 100 lm. In presented work
emulsions; however, emulsion III showed some delamination on analysis of emulsion, particle sizes helped to observe that, except
day three. Low quantities of air bubbles and development of a emulsion III, the average particle size was in a relatively low range
heterogeneous layer could be observed in emulsions IV, V and VI. of 3.3 6.5 lm. This means that the emulsions stabilized with natu-
These changes did not result in adverse assessments though. As ral emulsifiers (IV, V, VI) displayed a stability comparable to that of
regards emulsions I and II, it was noticed that these emulsions the emulsion containing lecithin. The accumulated distribution of
exhibited appropriate homogeneity, a smooth and uniform struc- the dispersed phase particle sizes for emulsions IV, V and VI shows
ture and absence of clots after each test cycle. Their high and that the diameter of 90% of droplets was below 5 lm. Their distri-
proper stability was reaffirmed by the centrifugal test. They were bution was quite narrow and monodisperse (Fig. 5). The diameter
the only dispersion systems to pass the test without altering their of 90% of droplets was below 5 lm and the distribution of the dis-
structure. Certain changes suggestive of de-lamination were persed phase particle sizes was similar to that of emulsions IV, V
observed in the remaining emulsions after 20 min of the test. It and VI in the case of the emulsion stabilized with lecithin as well.
was particularly apparent in emulsion III. Finally, at the end of A marked system instability (presence of three fractions, high aver-
the test, there was noticed stratification of emulsion III. age particle size and a wide distribution of the dispersed phase
© 2014 Society of Cosmetic Scientists and the Soci et e Francaise de Cosm etologie 89
ß
International Journal of Cosmetic Science, 37, 82 91
Interestrified fats suitable for cosmetic emulsions M. Kowalska et al.
particles) could be observed in the case of emulsion III (Figs 5 and observed. It was the only emulsion that did not completely pass
6). A small particle size could also be noted in emulsion II, with the tests for stability, and its morphology indicated larger parti-
a two-fraction particle distribution. Appearance of an additional cles than in the other emulsions. Their average particle size had
fraction could be presumed to be a symptom of non-adsorbed parti- the greatest value, and the distribution was very wide. It can be
cles of an additional emulsifier in the continuous phase. That emul- claimed that the content of the polar fraction in emulsion III was
sion was stabilized with lecithin but also contained low quantities insufficient to stabilize that dispersion system. Remaining emulsions
of partial acylglycerols (MAGs and DADs) that arose in the process showed proper stability. Their average particle size and distribution
of interesterification. Taking all these results into consideration, it resemble those of a monodispersive system. Respondents character-
could be concluded that synergies between these two types of emul- ized emulsions as easy to scoop, not flowing or pouring around the
sifiers were absent. According to Dickenson [10], the presence of skin. Emulsions IV, V and VI displayed cohesion and their consis-
such particles can affect the stability of an emulsion system. tency was that of cosmetic milk. Only emulsions I and II showed
Emulsions stabilized only with natural emulsifiers exhibited viscos- thick consistency; therefore, the respondents classified them as
ity of 1000 mPs*s, whereas emulsions I and II displayed far greater creams. In general, all the emulsions were absorbed well and fast,
viscosity values. Emulsion III showed the minimal viscosity (Fig. 6). and the skin after 1 h of application displayed a palpable greasy
Morphology of emulsions I and II exhibited the greatest systemic deposit of the substance. Ninety percent of respondents assessed the
homogeneity (Fig. 7). It seemed that their droplet size was compa- skin to which the emulsions had been applied as smooth and pleas-
rable and their arrangement suggested an orderly, homogeneous ant to touch.
nature. Larger isolated drops were observed in the remaining In summary, the work has demonstrated the possibility of apply-
systems of E IV, V, and VI. Perhaps, the presence of natural ing interesterified fats as the fatty base in cosmetic emulsions.
emulsifiers in the emulsion requires other homogenization Emulsions formed on the basis of interesterified fats without any
conditions (a different magnitude of RCF or other homogenization additional emulsifiers (sunflower lecithin) had properties compara-
time). Therefore, further study is needed to learn how to avoid lar- ble to emulsions containing mixed non-interesterified fat. It should
ger isolated drops before application of such emulsions as a com- be pointed out that the emulsions based on interesterified fats
mercial product. exhibited an even greater level of moisturization of the skin than
Such a merger into larger drops may initiate coalescence [27]. those containing non-interesterified fat. The natural emulsifiers
Generally, emulsion coalescence, in which some neighbouring formed as part of interesterification allowed us to obtain stable
droplets form larger droplets, damages an original emulsion and is emulsion systems while giving the respondents the satisfaction of a
indicative of emulsion instability [28]. Morphology of emulsion III new product not yet available on the market.
pointed to a distinctly larger particle, possibly responsible for
reduced stability of the system (Fig. 7).
Acknowledgements
The authors wish to acknowledge Kazimierz Pulaski University of
Conclusions
Technology and Humanities in Radom, Poland for financial
In the results of the presented work on the stability of emulsions support.
I-VI, an unsatisfactory polar fraction in emulsion III was
References
1. Mirhosseini, H., Tan, C.P. and Taherian, emulsions for use in lipstick formulations. 11. Kowalska, M., Zbikowska, A. and Gorecka,
A.R. Effect of glycerol and vegetable oil on Int. J. Cosmet. Sci. 33, 263 268 (2011). A. Effect of selected thickeners on oil drop-
_
physicochemical properties of Arabic gum- 6. Rozanska, S. Extensional viscosity of w/o let-size distribution in low-fat emulsions.
based beverage emulsion. Eur. Food Res. emulsions. Procedia Eng. 42, 742 752 Food. Sci. Technol. Qual. 4, 84 93 (2011),
Technol. 228, 19 28 (2008). (2012). (in Polish).
2. Kowalska, M., Zbikowska, A. and Szerling, 7. Van der Graaf, S., Schroen, C.G.P.H. and 12. Dickinson, E. Food emulsions and foams:
K. Application of modified fats by enzymatic Boom, R.M. Preparation of double emulsions Stabilization by particles. Curr. Opin. Colloid
interesterification in emulsions. Ital. J. Food by membrane emulsification - a review. Interface Sci. 15, 40 49 (2010).
Sci. 23, 136 144 (2011). J. Memb. Sci. 251, 7 15 (2005). 13. Tzoumaki, M.V., Moschakis, T., Kiosseoglou,
3. Bouyer, E., Mekhloufi, G., Rosilio, V., Grossi- 8. Fechner, A., Knoth, A., Scherze, I. and Mus- V. and Biliaderis, C.G. Oil-in-water emulsions
ord, J.L. and Agnely, F. Proteins, polysac- chiolik, G. Stability and release properties of stabilized by chitin nanocrystal particles.
charides, and their complexes used as double-emulsions stabilized by caseinate- Food Hydrocoll. 25, 1521 1529 (2011).
stabilizers for emulsions: Alternatives to syn- dextran conjugates. Food Hydrocoll. 21, 14. Szelag, H. and Pauzder, B. Rheological
z
thetic surfactants in the pharmaceutical 943 952 (2007). properties of emulsions stabilized by acyl-
field? Int. J. Pharm. 436, 359 378 (2012). 9. Sun, C., Gunasekaran, S. and Richards, glycerol emulsifiers modified with sodium
4. Abdulbari, H.A., Abdurahman, N.H., Rosli, M.P. Effect of xanthan gum on physico- carboxylates. Colloid Surface A 219, 87 95
Y.M., Mahmood, W.K. and Azhari, H.N. chemical properties of whey protein isolate (2003).
Demulsification of petroleum emulsions stabilized oil-in-water emulsions. Food 15. Kowalska, M., Bekas, W., Gruczynska, E.
using microwave separation method. Int. J. Hydrocoll. 21, 555 564 (2007). and Kowalski, B. Modification of beef tallow
Phys. Sci. 6, 5376 5382 (2011). 10. Dickinson, E. Hydrocolloids as emulsifiers fractions by chemical and enzymatic inter-
5. Le Reverend, B.J.D., Taylor, M.S. and Norton, and emulsion stabilizers. Food Hydrocoll. 23, esterification with sunflower oil. J. Food
I.T. Design and application of water in oil 1473 1482 (2009). Technol. 3, 404 409 (2005).
90 © 2014 Society of Cosmetic Scientists and the Soci et e Francaise de Cosm etologie
ß
International Journal of Cosmetic Science, 37, 82 91
Interestrified fats suitable for cosmetic emulsions M. Kowalska et al.
16. Kowalska, M., Bekas, W., Kowalska, D., 20. Gerhardt, L.C., StrŹ V., Lenz, A., Spen- 24. Al-Bawab, A. and Friberg, S.E. Some perti-
assle,
Lobacz, M. and Kowalski, B. Modification of cer, N.D. and Derler, S. Influence of epider- nent factors in skin care emulsion. Adv. Col-
beef tallow stearin by chemical and enzy- mal hydration on the friction of human skin loid Interface Sci. 123 126, 313 322
matic interesterification with rapeseed oil. against textiles. J. R. Soc. Interface 5, 1317 (2006).
Am. J. Food Technol. 6, 521 528 (2007). 1328 (2008). 25. Hadgraft, J. Skin deep. Eur. J. Pharm. Biop-
17. Adhikari, P., Hu, P. and Yafei, Z. Oxidative 21. Zuang, V., Rona, C., Distante, F. and Berad- harm. 58, 291 299 (2004).
stabilities of enzymatically interesterified fats esca, E. The use of a capacitance device to 26. Trados, T.F. Future developments in cos-
containing conjugated linoleic acid. J. Am. evaluate the hydration of human skin. metic formulations. Int. J. Cosmet. Sci. 14,
Oil Chem. Soc. 89, 1961 1970 (2012). J. Appl. Cosmet. 15, 95 102 (1997). 93 111 (1992).
18. Costales-Rodr 1
guez, R., Gibon, V., Verh e, R. 22. Płocica, J., Figiel, W. and Tal-Figiel, B. Sen- 27. SjŹ J. Emulsions Fundamental and Practi-
oblom,
and Greyt, W.D. Chemical and enzymatic in- sory research of selected products of Framo- cal Approach. Kulwer Academic Publisher
teresterification of a blend of palm stearin: na company of the line  Chocolate Dordrecht, Dordrecht, Netherlands, pp. 1 24
Soybean oil for low-trans margarine formu- Delicacies . Pol. J. Cosmet. 15, 134 137 (1992).
lations. J. Am. Oil Chem. Soc. 86, 681 697 (2012), (in Polish). 28. Saito, M., Yin, L.J., Kobayashi, I. and Nakaj-
(2009). 23. PÅ‚ocica, J. and Tal-Figiel, B. Organoleptic ima, M. Comparison of stability of bovine
19. ISO. International Standards Official Methods properties of selected cosmetics containing serum albumin-stabilized emulsions prepared
8420: 2004, Animal and Vegetable Fats and raw plant material from sweet clover and by microchannel emulsification and homog-
Oils  Determination of Polar Compounds Con- rosemary. Pol. J. Cosmet. 12, 67 76 (2009), enization. Food Hydrocoll. 20, 1020 1028
tent. ISO, Switzerland, Geneva (2004). (in Polish). (2006).
© 2014 Society of Cosmetic Scientists and the Soci et e Francaise de Cosm etologie 91
ß
International Journal of Cosmetic Science, 37, 82 91