270
Q. Liu et al.
glycerol and fatty acids. And fatty acids linked to glycerol can form monoglycerides, diglycerides, or triglycerides. Traditionally, synthetic fatty acid glycerides
had been widely used in the cosmetics industry. Due to the enhancement of safety
and environmental consciousness together with the improvement in oil separation
and purification technologies, the yield and quality of natural oils and fats had been
improved. New antioxidants had solved the problems of natural plant oil deterioration, and high-quality natural plant oils can be obtained for natural cosmetic products
cost-effectively. Natural cosmetic products have become more and more favorable
to general consumers nowadays. In 2007, the Journal of Soap, Perfumery & Cosmetics (SPC) published several articles about oils and fats for cosmetic uses. The
supplier listed the physicochemical properties of various oils and fats in the product
specifications for the formulators to select the suitable oils and fats. However, it was
difficult to find the physicochemical parameters of various oils and fats.
9.1.1 Functional Assessment
The basic function of oil and fats in cosmetics is still controversial. Consumers
generally believe that oil can prevent skin from drying and cracking by inhibiting
moisture evaporation. It can rehydrate dry skin and hardened cuticle by restoring the
cuticle to being soft and elastic, making the skin smooth, soft, and elastic. Therefore,
it can be used as a moisturizer. Oil can also improve the smoothness of cosmetics,
which to a large extent determines the skin feeling of skincare products, such as
smoothness, lubricity, moisture retention, and breathability. Based on its smoothness
and softness characters, it can also be used as skin extender, elasticity and smoothing
agent. A few years ago, R Goldemburg tested 85 cosmetics emollients and proposed
the concept of skin feeling parameters and found no direct relationship between
molecular weight of oil and skin sensitivity [1]. Polar’s researching team believes
that highly unsaturated and branched oils are suitable for emollient uses [2], but John
Woodruf believes that isopropyl fatty acid is particularly suitable as an emollient [3].
Hans Brand tested the lubricity and spreadability of a large number of emollients, and
divided them into 3 levels: (1) protection, (2) lubricating, and (3) drying shrinkage
[4].
At present, many studies have assessed the physical and chemical properties of oil
through sensory test. Parente evaluated several liquid emollients, such as mineral oil,
sunflower oil, squalane, decyl oleate, isopropyl myristate, and octyl dodecyl, using
instrumental and sensory tests [5]. Wiechers tested their smoothness, luminescence,
viscosity, smoothness and oiliness associated with the relative polarity parameters
(RPI). The RPI value can be used for the polarity determination of the cuticle and
the emollient, which makes it easy to select the best emollient for the skin use [6].
Studies to assess the efficacy of oils in cosmetics through sensory tests are being
continued. Jan Dekker published a pamphlet that briefly describes the physical and
chemical properties of various oils, explaining how the oils were obtained and applied
to the appropriate locations. Steam distillation removes odors, fatty acids, peroxides,
Q. Liu et al.
glycerol and fatty acids. And fatty acids linked to glycerol can form monoglycerides, diglycerides, or triglycerides. Traditionally, synthetic fatty acid glycerides
had been widely used in the cosmetics industry. Due to the enhancement of safety
and environmental consciousness together with the improvement in oil separation
and purification technologies, the yield and quality of natural oils and fats had been
improved. New antioxidants had solved the problems of natural plant oil deterioration, and high-quality natural plant oils can be obtained for natural cosmetic products
cost-effectively. Natural cosmetic products have become more and more favorable
to general consumers nowadays. In 2007, the Journal of Soap, Perfumery & Cosmetics (SPC) published several articles about oils and fats for cosmetic uses. The
supplier listed the physicochemical properties of various oils and fats in the product
specifications for the formulators to select the suitable oils and fats. However, it was
difficult to find the physicochemical parameters of various oils and fats.
9.1.1 Functional Assessment
The basic function of oil and fats in cosmetics is still controversial. Consumers
generally believe that oil can prevent skin from drying and cracking by inhibiting
moisture evaporation. It can rehydrate dry skin and hardened cuticle by restoring the
cuticle to being soft and elastic, making the skin smooth, soft, and elastic. Therefore,
it can be used as a moisturizer. Oil can also improve the smoothness of cosmetics,
which to a large extent determines the skin feeling of skincare products, such as
smoothness, lubricity, moisture retention, and breathability. Based on its smoothness
and softness characters, it can also be used as skin extender, elasticity and smoothing
agent. A few years ago, R Goldemburg tested 85 cosmetics emollients and proposed
the concept of skin feeling parameters and found no direct relationship between
molecular weight of oil and skin sensitivity [1]. Polar’s researching team believes
that highly unsaturated and branched oils are suitable for emollient uses [2], but John
Woodruf believes that isopropyl fatty acid is particularly suitable as an emollient [3].
Hans Brand tested the lubricity and spreadability of a large number of emollients, and
divided them into 3 levels: (1) protection, (2) lubricating, and (3) drying shrinkage
[4].
At present, many studies have assessed the physical and chemical properties of oil
through sensory test. Parente evaluated several liquid emollients, such as mineral oil,
sunflower oil, squalane, decyl oleate, isopropyl myristate, and octyl dodecyl, using
instrumental and sensory tests [5]. Wiechers tested their smoothness, luminescence,
viscosity, smoothness and oiliness associated with the relative polarity parameters
(RPI). The RPI value can be used for the polarity determination of the cuticle and
the emollient, which makes it easy to select the best emollient for the skin use [6].
Studies to assess the efficacy of oils in cosmetics through sensory tests are being
continued. Jan Dekker published a pamphlet that briefly describes the physical and
chemical properties of various oils, explaining how the oils were obtained and applied
to the appropriate locations. Steam distillation removes odors, fatty acids, peroxides,