Exploring Characterization Techniques in Body Lotion Analysis

This report provides an overview of the characterization techniques used in the analysis of body lotion, emphasizing the importance of sensory, rheological, and textural characterizations in ensuring product efficacy, consumer acceptability, and aesthetic appeal. It focuses on rheological characterization, detailing the scientific and engineering basis of the technique, including the use of an ARES rheometer to measure shear flow and viscosity. The report also discusses the advantages and disadvantages of rheological characterization and its role in controlling the quality and physical characteristics of body lotion formulations, ultimately affecting the product's consistency, stability, and shelf life. The study references research utilizing ARES rheometer to correlate viscosity and shear rates with customer acceptability factors. Desklib offers a wealth of similar solved assignments and study resources for students.

Characterization Techniques of Body Lotion 1
MEASUREMENT TECHNIQUES USED IN CHARACTERISATION OF A FORMULATED
PRODUCT
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Characterization Techniques of Body Lotion 2
The Characterization Techniques of Body Lotion
Introduction
During the design of a cosmetic product, the acceptability of the product by the
consumers is one of the most important points to consider during the formulation of the product.
Other important aspects include the ability of the product to fulfill the demands of the customers
in terms of what they need in such a product, as well as a satisfactory aesthetic level of the
product as can be perceived by all senses. This is because the products tend to be applied on the
skin of the characters, such that they interact with all the sensorial characteristics of the user,
emphasizing the importance of sensorial aesthetics in the product. It also ought to be able to
achieve the purpose the product is intended to bring about in an efficient manner, such that both
the real and perceived purposes of the products are guaranteed. To guarantee that all these factors
are achieved in the formulated product, different characterization techniques namely the sensory,
rheological, and textural characterizations ought to be conducted on the product (McMullen,
Gorcea, & Chen, 2016).. This allows for the determination of the perceived and real efficacy of
the product to ensure that the product meets the needs of the consumers and serves them in a
manner they like so that the product can remain successful. This study will conduct a rheological
characterization to the product and explain the other techniques applicable for the analysis.
Body Lotion as a Formulated Product
A formulated product refers to a product that has been manufactured through the process
of combining different ingredients that are unable to chemically react with each other, in order to
come up with products that have a desirable outcome for the purposes they are used for. As such
different components to be used in a formulation have to be all compatible and contributing to
the expected product. The products ought to be compatible with each other to bring out a soluble

Characterization Techniques of Body Lotion 3
compatible mixture, whose individual components actively contribute to the efficacy of the
product for its intended purpose as well for aesthetic purposes. For this reason, skin lotion or
body lotion can be considered a formulated product because the product is made up of different
ingredients that form a seemingly stable mixture that can be used to moisturize the skin of an
individual. As such, skin lotions contain a mixture of oil as well as water ingredients which
provide the product with its ability to serve its intended purpose of moisturizing the skin of the
user. This is achieved when water that is found within the skin is prevented from escaping from
the skin through either attracting water from the atmosphere into the skin, changing how the skin
feels, and even blocking the water depending on the skin type of the user. Other ingredients that
are combined into the formulation of skin lotions serve to stimulate the proteins of the skin in
order to sooth any senses of dryness on the skin, thus serving the purpose the formulation is
intended for (Holt &Barr, 2002).
There are also ingredients that are combined into the formulation in order to improve the
color, smell and consistency of the product, in order to make it favorable for use by the market as
it stimulates all the sensorial characteristics as well as the aesthetics of the product. The body
lotion thus is able to retain moisture and allow the skin to continue with its normal physiological
processes. In the product’s ability to deliver high levels of moisturizing to the consumer’s skin
guarantees an equally high degree of consumer acceptance. This is achieved through the
product’s ability to be non-tacky, quick to be absorbed into the skin and even with a low level of
greasiness. The moisturizing abilities of the product will in this manner be enhanced and thus
giving the consumer a good feel on their skin, which translates to high consumer acceptability.
The other factors that qualify the product as a formulated product are its ability to fulfill the need
of the client in the given product thorugh its excellence in moisturizing the skin and allowing the

Characterization Techniques of Body Lotion 4
skin to continue performing its normal functions optimally. In being non-tacky and without high
levels of grease, the product is also able to fulfil the last requirement of a formulated product
which is to ensure that it has a satisfactory aesthetics level as can be perceived by all the senses.
This is achieved in the requirement that the product ought to have a good feel on the skin of the
consumer.
Scientific Basis of Rheological Characterization Technique
To select the right analytical tool to measure the efficacy of body lotion as a formulated
product, different characterization tools ought to be considered based on the main parameters to
be considered for the success of the formulated product. For body lotion, rheological
characterization techniques are of extreme importance as they tend to explain the consistency of
the product, which in turn determines the efficacy, aesthetics and sensory characteristics of the
formulated product. Primarily, the rheological factors determine the usage conditions of the
product by measuring the shear flow conditions of the product that allow it to spread using a
measurement tool known as a rheometer. The image below depicts an ARES rheometer, which is
a commonly used strain-controlled rheometer. The ARES rheometer is a device where the
rheological properties of a material can be determined through a set of controlled levels and rates
of dynamic and steady shear strain in order to identify the torque that results from the effect of
the shear strain. The ARES controlled strain machine uses a step motor to measure the values of
the torque through a mechanism known as the Force Rebalancing Transducer (FRT). This
transducer is exposed to the shear strain, either dynamic or steady and thus displays the value of
the resultant torque. The following images depict the ARES strain controlled rheometer and the
individual parts that allow it to measure the rheological properties of the materials and products
that are placed to be measured.

Characterization Techniques of Body Lotion 5
Figure 1: ARES strain controlled rheometer

Characterization Techniques of Body Lotion 6
Figure 2: Working principle of an ARES strain controlled rheometer
Figure 2: Working principle of an ARES strain controlled rheometer
For the rheological properties of a skin lotion to be measured using this technique using
the ARES strain controlled rheometer, the steady state shear strain measurements were first taken
with a parallel plate fixture of a given radius and gap size. The shear flow measurements will
also be taken in a fixed temperature taken to be the same temperature as that of the skin of an
individual. The shear strain rates will then be varied shear rate and then the resulting torque
related to the shear rates by plotting the two variables on a logarithmic scale.

Characterization Techniques of Body Lotion 7
This was repeated for the dynamic state shear strain level for purposes if establishing the
viscoelastic behavior of the product given the shear flow of small amplitude oscillatory fields.
The temperature for this test was also limited to 36 degrees centigrade which is the normal
temperature of human skin. During this stage of dynamic evaluation, the angular frequencies
were varied so that any difference in the viscoelastic properties of can be identified and noted
through plotting these variables on a logarithmic scale. The steady state shear flows were used
for the determination of shear strain rates and dynamic state shear flows were used to predict the
shear rates and the angular frequencies that are commonly applied while rubbing and spreading
the product.
For instance, the consistency of body lotion determines the quality of the product in terms
of the composition of the different ingredients that have been used in the formulation of the
product and thus its effectiveness in moisturizing the skin of the user. Further, the consistency of
the product also determines the stability of the product for storage purposes since the success of
the product and its shelf life is determined by the period of time that the product can remain in its
seemingly stable mixture state. This guarantees that the product has a good aesthetic value of
visibility when used as well as a good depiction of sensorial characteristics.
Engineering Basis of Rheological Characterization Technique
Rheological Characterization technique seeks to identify the parameters of the lotion that
will affect the quality and the aesthetic aspects of the project. The rheological analysis allows
important parameters such as the viscosity of the product to be tested. For instance, when the
viscosity of the formulation is too high, the force used to apply the product may be relatively
high. Lotions require a consistency that promotes high yield stress during rest conditions so that

Characterization Techniques of Body Lotion 8
the lotion could stay when applied and so that it can be squeezed or pumped out of a bottle. High
shear is also required as a mechanical property of the liquid to ensure that the product remains
applicable for increased efficacy of the product.
Further, the consistency and viscosity of the product is dependent on the shelf life
duration of the product such that a long duration results in the reduction of the viscosity and
consistency of the product. The rheological properties of the product can be controlled by
considering the amount of ingredients, as well as the shape and size of the oil particles to be
emulsified in the continuous phase of water
(Manral, 2016).
Other engineering aspects that are tested through rheological characterization also include
the behavior of the product with regard to its flow during the production processes, ranging from
the mixing processes, pumping and packaging. It is important to note that changes in the
consistency of the product will in this manner affect the characteristics of the end product and its
suitability for use, as well as the engineering considerations taken during the production stages.

Characterization Techniques of Body Lotion 9
Rheological characterization can be altered by investigating the stability of the formulation
through investigating the consistency of the product. Maravkova and Stern (2011) seeks to
establish the important points to consider in the formulation of a product like body lotion
including the customer acceptability of the product, the efficacy of the product for its intended
purpose, as well as the aesthetic properties of the formulation and the feel the product has on the
skin. Conducting a rheological analysis of the product aided the researchers to assess the
viscosity and the shear rates of the product. The study utilized an ARES rheometer to establish
these Newtonian parameters. The values of the viscosity and the shear rates are utilized to
determine the perfect consistency of the product through guaranteeing a high correlation between
the two variables. This in turn allows the researchers to determine the important customer
acceptability values like the ease of spreading and drawing the material from the container
although the correlation value obtained of 0.52 was too low to actually design or property of the
product using these figures. The thickness of the formulation and the impact this parameter has
on the feel of the skin and the effectiveness of the product for its function were also determined
to have a correlation factor of -0.75 discouraging the prediction of the design of any formulation
using this data.
Advantages and Disadvantages
Rheological characterization is advantageous first and foremost because it allows for the
quality and physical characteristics of the formulation to be controlled, for purpose of
guaranteeing efficacy, aesthetic satisfaction, and sensorial characteristics. Lotion needs to attain
a certain level of consistency such that it remains applicable to the human skin without being too
heavy or sticky. Rheological characterization guarantees that a uniformly thin layer of lotion is
left behind after application, so that it serves the purpose of moisturizing and hydrating the skin.

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Rheological characterization also guarantees that the shelf-life of the product is guaranteed by
ensuring that the ingredients of the formulation do not destabilize and separate into the individual
ingredients, to lose the smooth creamy consistency of the product. The product also ought to
look, feel and smell nice after being squeezed from the bottle to ensure that the sensorial
characteristics of the products have been considered. The technique is for this reason very useful
in the determination of aspects such as quality control, the differences in the stability of the
product during varying temperature conditions and during transportation, efficacy for its
intended purpose, consistency of the product, as well as the flow characteristics that are of
extreme importance during formulation and transport. In this sense, rheological characterization
is important because it identifies the parameters that are necessary for the applicability of the
product on the skin, the thermal conditions for storage of the product and the different
parameters to consider during the manufacturing stages.
Due to the sensitivity of rheological characterization to the physical properties of the
product, rheological testing only focuses on bringing out the penetrometry and viscosity related
parameters. This poses as disadvantage as to the identification of only the consistency values
that are limited in their measurement of different physical properties of the product. For instance,
rheological characterization leaves out aspects such as creep testing and its impact in the
viscoelastic properties of the product, the methods is therefore disadvantageous as it fails to
consider the impact of transient methodologies that become ignored during short-time based
analytical methods. The technique therefore ignores the inertial impacts as well the effects of
parameters that cannot be tested instantaneously. As such, the technique ignores other important
parameter that could impact the quality, efficacy, aesthetic values, and even the sensorial
characteristics of the product (Davis, 2001).

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Three Other Applicable Techniques
As has been earlier explained, the role played by the ability of the product to impact on
sensorial characteristics, the efficacy of the product for the intended purpose, and the real and
perceived aesthetical values of the product cannot be underplayed. This is because these factors
are the major determinants of the characterization techniques that can be employed to test the
efficacy of the products. However, there are other techniques that can be employed for this
specific product including the sensory and textural characterization techniques.
Sensory characterization is widely used in the field of processing and manufacturing
since the recent past, as the technique has demonstrated sophistication, applicability, and even
reliability when it comes to the determination of sensory characteristics of products. The
scientific basis of sensory characterization is that a descriptive assessment of the product is done
by trained evaluators and assessors and through the use novel methods. Sensory analysis mainly
relies on an instrument that is known as the Spectrum Descriptive Analysis Tool which is a
qualitative analysis tool that was developed in the 1950s by the Arthur D Little Company to
identify the suitability of products that require detailed description of flavors and products. The
method utilizes a panel which uses a qualitative description methodology of using a scale of up
to 14 points in order to adequately describe the sensory quality of the product being tested in
detail. In this methodology, the product is compared to an existing product as the control sample
for calibrating the accuracy and even referencing the attributes of the product being tested. The
panelists that are involved in sensory testing are mainly extensively trained in order to accurately
validate the products and guarantee integrity of the product being formulated. This specific tool
that was developed a couple of decades ago and which continues to be improved by the sensory
characterization professionals also incorporates statistical aspects to the data collected from the

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panelists in order to support the interests of product developers to create products with good
attributes and intensities. In so doing, the Spectrum descriptive analysis method guarantees that
the progress of development of te product, as well as the ingredients and the impact of time on
the product are documented in the process.
This technique enables a good comparison of the different samples being compared
specifically regarding the sensory aspects of the product. The Spectrum Descriptive Analysis
Tool allows for the investigation of sensory aspects such as the ease of drawing or dispensing the
lotion from its container, the ease with which it spreads on human skin regardless of the different
skin types, the feeling that this lotion gives the skin during the absorption process as well as how
it feels after it has been rubbed into the skin (Filip and Moravkova, 2017). It also considers all
forms of unpleasant sentiments that could negatively impact the attitude of the consumers of the
formulated products, despite the other good attributes like quality and aesthetic perception. This
allows the developers of the formulation to be aware of any characteristics of the product that
could affect its acceptability for use by the clients, regardless of being a good quality product.
Sensory characterization however takes up a huge chunk of the budgetary and even time-based
resources, because any slight alteration of the ingredients and their compositions may require the
entire process to be repeated from scratch (Parente, Mbaro, & Ares, 2008).
To guarantee that the sensory scales were completely representative of the true sensory
effects of the samples, the scale has also been multiplied by 100 to ensure that a true depiction of
the sensory attributes is recorded from a scale of 100 for excellent and 0 for very poor. The
sensory assessment is also to be carried out according to set standard practices according to ISO
13299, 8, and ISO 8589 standards. However the procedure is very expensive with regard to both