Macadamia (Macadamia in­tegrifolia) nut oil has been avail­able to cosmetic

formulators since 1985 with early ap­plications in the emerging range of 'liposome' products.

The oil was erroneously thought to have the same typical oxidative stability problems as other trigly­ceride oils from botanical sources. However, macadamia nut oil's stabil­ity is just the opposite . This unique botanical produces one of the most stable natural emollients available.

The inclusion of mixed, natural tocopherols augments macadamia nut oil's stability even further. Superior oxidative stability, particu­larly in the presence of certain pig­ments and sunscreen additives, combined with its exceptional emollient properties, elegant skin feel and consumer appeal, makes macadamia nut oil an excellent

Macadamia nut I OILS & FATS

choice for a range of skin treatments, sunscreens, aromatherapy oils, lip­sticks and decorative products .

Oxidative stability The total unsaturated fatty acid con­tent of macadamia nut oil is typically greater than 85%. Since the unsatu­rated fatty acids present in the oil are almost entirely mono-unsaturated and not polyunsaturated, macadamia nut oil has excellent oxidative stabili­ty (ie an unusually high resistance to rancidity) . This is verified through the use of an oxidative stability in-

Benefits • good oxidative stability • good emolliency • elegant skin feel • wide consumer acceptance • versatility

strument (American Oil Chemists' Society Method Cd 12b-92).

The oxidative stability · index (OSI) of macadamia nut oil has al­ways rated high (OSI of20-2S hours) relative to other naturally •derived oils (OSI of 2-15 hours). When 500ppm natural tocopherols are added to macadamia nut oil, the OSI more than triples, increasing to about 70 hours. Adding lO00ppm tocopherols can increase the OSI to more than 100 hours and the use of synthetic antioxidants can boost the OSI stability of macadamia nut oil to even higher values.

Hawaiian macadamia nut oil ranks very high on the list of stable cosmetic oils, ahead of oils such as squalane, sesame oil, almond oil, hybrid safflower oil and hybrid sun­flower oil.

Figure 1 illustrates the relative ox­idative stability of several oils com­monly used by the cosmetic industry, including mink oil. Mink oil is

Figure 1 • Relative OSI indices of natural oils

Figure 2 - Effect of sunscreen additives on macadamia nut oil oxidative stability

OSI vah.Jc, hours

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(w/locophcrols)

aurt~l!n:11111lll lll ll~ ~ l\.dd 1Um l,i,,iel ◄ 0;i'.;,:,/1nt? OSI ol m,,r:,1cl,ll'r1,1 r.ut oil '.'i1ll1 ro 5Ufl'.;U!!!'ll atJU,t1Vl"; col'{; t1a,w-.

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Almond oil

Sesame oil

included in this comparison because mink oil and macadamia nut oil are the only commercially available sources oflipids with significant lev­els of palmitoleic acid (Cl6:l). Macadamia nut oil provides the ele­gant feel of mink oil, but is derived from a botanical source and its ox­idative stability far exceeds that of mink oil. An added benefit of inte­grating macadamia nut oil into a manufacturing programme is the warehouse stability of the oil com­pared to other oils such as sesame or almond. OSI values can be used to es­timate material shelf life as well.

When properly prepared, maca­damia nut oil is odourless, clear and colourless. It has excellent skin feel and a very positive consumer appeal. The additional benefit of resistance to oxidation puts macadamia nut oil at the top of the list of emollient oils commonly used in cosmetics. Macadamia nut oil can be used in for­mulations in the same way that other triglyceride oils are used. Macadamia nut oil contributes a unique emol­liency in lipsticks and lip protection products. An example of a good lip protectant containing macadamia nut oil is shown in Formulation 1. The macadamia nut oil in this lip balm forms an occlusive, emollient moisture barrier on the lips which helps keep lips soft and supple when exposed to the elements.

Many other formulas have been developed specifically for use with macadamia nut oil. Formulation 2 is an example of a lotion containing macadamia nut oil. This lotion spreads easily and absorbs quickly into the skin. Appropriate modifica­tions to this oil-in-water emulsion would yield excellent facial mois­turisers, pre-sun or aftersun products and hand and body lotions. ·

Its oxidative stability responds in interesting ways when macadamia nut oil is mixed with sunscreens (titanium dioxide in particular). A study was conducted to observe the effect of different popular sunscreen agents on the oxidative stability of macadamia nut oil. Figure 2 illus­trates these results.

Oc\yl rJ,m~thyl PAfJA

Octyl molho,_:,cmnam:ah.-

Most of the sunscreen agents tested increased the already high oxidative stability of macadamia nut oil. Combining 10% titanium dioxide with macadamia nut oil (containing mixed natural toco­pherols) increased the oxidative stability of the oil by 300%. This information may be useful for sun care formulators and serves as an aid in selecting emollients in sun­screens to promote the oxidative stability of finished products.

Colour cosmetics (lipstick, eye shadow, foundation) are currently

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undergoing exceptional growth in many world markets. Certain pig­ments are known to promote oxida­tive instability in colour cosmetics, especially when used in high con­centrations. Macadamia nut oil was found to be affected as well, but not as drastically as other natural oils commonly used in colour cosmetics. Figure 3 illustra!es these findings.

The addition of 10% iron oxide pigment to control oils (containing 1 000ppm mixed natural toco­pherols) caused a decrease in the ox­idative stability of all the tested oils.

Figure 3 • Oxidative effect of adding 10% iron oxides to botanical emollients

n m 20 Macadamia nul oil

Hybrid sunflower oil

T raditiona1 sunflower oil I

Almond oil

Sesame oil

OSI value, hours ,•0~00 10

) CO!\llol 10 hono~•IJl."!o

Figure 4 • Oxidative effect of skin whiteners on botanical emollients

10 20

Macadnmia nut oil

Hybrid sunflower oil

Traditional sunflower oil .-

l

Almond o il r -Sesame oil • -

30 OSI value, hours

.IQ L.Jl!1 70 1)11

) Control J Arbulin, ]f/..,

Kojic acid, 1 % l lvlAP 3%

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I

Figure 5 • Oxidative effect of malic & salicylic acid on botanical oils

Macadamia nu\ ad

Hybrid sunl!o'l,t>r oil

Almond.,,] ,-

OSI value, hours 10 :i , i~ , rn 120 130 ,.rn ,so

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Macadamia nut I OILS & FATS

Formulation 1 • Macadamia lip balm

INCi name Trade name Supplier %

A Macadamia ternilolia nut oil Floramac Floratech 30.00 (Hawaiian macadamia nut oil) Castor oil qs Hybrid sunflower Florasun 90 Floratech 4.50 (Helianthus annuus) oil Jojoba esters Floraesters 30 Floratech 6.00 Jojoba esters Floraesters 70 Flora tech 1.15 Carnauba wax Carnauba Wax #1 Strahl & Pitsch 3.80

Yellow SP 63 (Copernicia cerilera) Candelilla wax Candelilla Wax SP 75 Strahl & Pitsch 6.60 (Euphorbia cerilera) Beeswax Yellow Beeswax SP 6P Strahl & Pitsch 4.00 Hydrogenated castor oil Castorwax-NF CasChem 1.60 Cetyl ricinoleate NatureChem CR CasChem 1.60 lsopropylparaben (and) LiquaPar oil Sutton qs isobutylparaben (and) Butylparaben

B Titanium dioxide (and) Solaveil FLO ICI 3.00 Hybrid sunflower (Helianthus annuus) oll

C Octyl methoxycinnamate Parsol MCX Roche 7.10 Tocopherol Henkel 0.10 Flavour Artificial Macadamia Nut Bell Flavors & 0.45

Flavour OS Fragrances

Preparation - Combine Ingredients of phase A and heal to ss•c with moderate agitation. Add phase B to

phase A and mix with propeller agitation. Cool batch to 75'C, add phase C and mix with propeller agitation.

Fill as soon as possible.

However, the stability of macadamia nut oil containing iron oxide was higher than the stability of other tested oils. Similar results were found in the presence of 10% zinc oxide. Hybrid sunflower oil also ex-

hibited good stability in the presence of 10% iron oxide pigment.

Macadamia nut oil has also been found to excel as an emollient oil in skin whitener formulations. Skin whiteners sometimes develop rancid

odours within a short period of time. In our laboratory, we mixed either 1 % kojic acid, 7 % arbutin or3 % magne­sium ascorbyl phosphate (MAP) into macadamia nut oil and other botani­cal oils ( containing 1 000ppm mixed natural tocopherols).

1 We determined the oxidative sta­bility of these control oils and com­pared the results with the same oils containing the whiteners. Results are presented in Figure 4. Overall, macadamia nut oil exhibited signifi­cantly greater oxidative stability in the presence of whiteners than other oils tested. Hybrid sunflower oil also exhibited good stability. Kojic acid extended the oxidative stability of macadamia nut oil (20%) and hybrid sunflower oil (17% ).

The expanded use of AHAs and BHAs warranted a study of the effect these types ofingredients have on the oxidative stability of natural oils. A number of the control oils were test­ed containing l000ppm mixed nat­ural tocopherols. To each oil was added 5% malic acid or 2% salicylic acid. The oxidative stability of these oils was then tested.

Malic acid was chosen because it is considered to be an alpha hydroxy acid (AHA), while salicylic acid is a

OILS & FATS I Macadamia nut

beta hydroxy acid (BHA). Figure 5 illustrates that malic acid improved the oxidative stability of macadamia nut oil and hybrid sunflower oil. Traditional sunflower oil and al­mond oil lost oxidative stability in the presence of malic acid.

The addition of salicylic acid gen­erated improvements in the oxida­tive stability of macadamia nut oil, hybrid sunflower oil and sesame oil. As with malic acid, traditio_nal sun­flower oil and almond oil lost oxida­tive stability in the presence of salicylic acid. Attempts to measure the effect of glycolic acid on the ox­idative stability of botanical oils were not successful.

Among botanical emollients, macadamia nut oil is functionally one of the most oxidatively stable emol­lient oils available to the cosmetic formulator. In addition to its func­tional benefits, consumer perception of macadamia nut oil is of an upscale, high-end, high quality product. This is reinforced by the high price that macadamia nuts command in the re­tail market. This safe, pla'nt-derived oil is from a renewable resource and comes from a stable and increasing supply base. Its rich, 'cushiony' skin feel makes macadamia nut oil an ex-

lhe Halurcl folulian

floratech.com

Formulation 2 • Skin softening lotion

INCi name Trade name Suppller %

A Macadamia ternilolia nut oil Floramac Hawaiian Floratech 2.00 macadamia nut oil

Jojoba eslers Floraesters 20 Floratech 2.50 Jojoba esters Floraesters 30 Flora tech 5.00 Glyceryl stearate Lexemul 561 lnolex 3.00 (and) PEG-100 !

Cetyl alcohol Lanette 16 Henkel 1.00 Slearyl alcohol Cosmowax P Croda 0.50 (and) ceteareth-20 Dimethicone SF 96 - 200 Silicone Fluid General Electric 0.20 Propylparaben Sutton qs.

B Deionised water qs Jojoba wax PEG-120 esters Florasolvs Jojoba PEG-120 Flora tech 4 00

C Propylene glycol Dow 5.00 Algin Kelgin HV Kelco 0.20 Methylparaben Sutton qs lmidazolidinyl urea Germall 115 Sutton qs

D Fragrance qs

Preparation• Heat phase A to 75'C with agitation. Heat phase B Co 75'C with agitation . Add Rorasolvs Jojoba

PfG-120. Pre-mix phase C with moderate agitation and add slowly Co phase B with moderate high-speed

agitation . Mix for 15 minutes. Add phase A slowly to phase BC _with propeller agitation. Force cool to 40'C

with agitation. Add fragrance (if desired) and mix with propeller agitation Co room temperature.

cellent choice for skin care and lip care products.

References 1. Cummings M, Arquette J, Reinhardt J, Cosmetics & Toiletries, 114 (1) 75-78 (1999) 2. Calvo L, Cosmetics & Toiletries, 110 (2) 33-38 (1995) 3. Dunn C, Happi, 33 (8) 53-58 (1996)

f LORA JECH SINCE 1915

♦ Plant Derived

♦ Non GMO

♦ Long Shelf Life

♦ All Products Approved in Japan

AMERICAS • EUROPE • ASIA

4. Brown J et al, Cosmetics & Toiletries, Vol 112 (7), p87 (1997)

Authors Floratech 1151 N Fiesta Blvd Gilbert, AZ 85233 us Tel: + l 480 545 7000 Fax: + 1 480 892 3000

FLORATECH CORPORATE OFFICE

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Tel: 480 545 7000 Fax: 480 892 7000

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Reprinted from SPC May 1999