98 Eur. J. Lipid Sci. Technol. 103 (2001) 98–101

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Phospholipids for functional foodMichael Schneider

Lipoid GmbH, Ludwigshafen, Germany

Summary

Phospholipids are the functional ingredients of lecithins.Their synergistic technological and physiological proper-ties make them attractive and unique candidates for theformulation of functional food. However, there are a lot ofhurdles to overcome until an acceptable product in termsof taste and texture can be obtained.

Lecithins are widely used, highly functional standard ad-ditives for food. Their phospholipid composition is of greatrelevance for their technological and even more for theirphysiological properties.

Defined phospholipids and phospholipid mixtures exhibitwell-documented nutritional and/or therapeutic benefits.

Even though they are known as food emulsifiers world-wide and although at the same time they have a very pos-itive image, their use in functional food is still limited.

But considering the solid basis of clinical data, there is nodoubt that phospholipids will become standard ingredi-ents for this rapidly expanding category of food.

Introduction

In 1811 the french chemist Vauquelin was the first to de-scribe a substance containing organically bound phos-phorus, obtained from animal brain [1]. After Gobleyextracted a similar – orange-colored, emulsifying – com-pound, he gave this material the name Lecithin (from theGreek word Lekithos for egg yolk) [2].

In 1921 Hermann Bollmann from the oil mill of Hamburgfiled a patent about refining vegetable oils, opening thedoor for large scale industrial manufacture of cheap veg-etable lecithins [3].

What is lecithin?

According to the commercial terminology lecithin is acomplex mixture of polar lipids (phospholipids and glyco-lipids) which may contain up to 40% of oil and which is extracted from animal or vegetable food products. Thedefinition for the food additive lecithin (in Europe under E

322) also includes fractions and enzyme hydrolized prod-ucts [4].

What are phospholipids?

Phospholipids are the functional ingredients of lecithin.They are phosphorous-containing polar lipids having abipolar, amphiphilic molecular structure with a lipophilicpart in form of two fatty acids and a hydrophilic group inform of a phosphoric acid ester (Fig. 1).

The type of phospholipid is determined by the type of sub-stance linked to the phosphate group. Most of it’s physi-cochemical properties is determined by the type of headgroup but also by the type (especially degree of unsatura-tion) of fatty acids.

The nature of fatty acids in position 1 and 2 of the glycerolbackbone can vary to an extensive degree, dependent onthe source of the phospholipid and/or eventually hydro-genation.

The predominant use as natural, nontoxic emulsifiers,wetting and dispersing agents, as e.g. in [5]

● margarine● chocolate● bakery goods● instant products● cosmetics● pharmaceuticals

finds its explanation in the unique molecular structure ofthe phospholipids.

For all these applications mentioned, nutritional proper-ties do not play any role because used quantities in foodproducts (as emulsifiers) normally range between 0.3 and1.0% only.

Nutritional properties of phospholipids

Even though already in 1905 the first egg-based lecithinwas marketed, it took until 1954 till the first soy lecithinbased nutritional drink got on the market. Today this prod-uct is a well-known and successful product in all Germanspeaking countries. It’s position as a product for generalstrengthening and as nerve nutrient however is verybroad and unclear.

Similar to the difference in technological properties of allthe phospholipids, the specific physiological effects areclearly related to well-defined substances.

The development of more sophisticated processing tech-nologies like solvent fractionation and column chromatog-

Correspondence: Michael Schneider, Lipoid GmbH, Frigen-straße 4, D 67065 Ludwigshafen. Phone: +49-621-53819-37,Fax: +49-621-53819-55; e-mail: schneider@lipoid.de

raphy [6] made it possible to concentrate or even to iso-late certain phospholipids and to investigate their physio-logical effects clinically.

At the same time this technology enabled companies todevelop and market certain product categories with well-defined nutrional benefits.

The following list selects just a few phospholipid productsand their physiological effects which are well investigatedand confirmed:

● soy phospholipid mixtures of natural composition

– to reduce elevated blood lipids (cholesterol, triglyc-erides) [7]

● soy phosphatidyl choline

– for liver detoxification and repair of damaged livertissue [8]

● phosphatidyl serine (soy, brain, other sources)

– to improve cognitive functions [9]

● egg phospholipids

– for infant formula to improve visual acuity [10]

The total annual consumption of these phospholipids isremarkably high (approximately 3,000 t/year) eventhough their market position suffers from the fact that tilltoday they have not yet got very qualified general publicawareness.

Besides this, most of the products are marketed under theconfusing term lecithin which allows no clear differentia-tion according to the type of phospholipid and its nutri-tional profile.

Phospholipids and functional food

What is functional food?

Here is one of the many’s definition according to Gold-berg [11]:

“Generally, a functional food can be defined as any foodthat has a positive impact on an individual’s health, phys-ical performance or state of mind in addition to its nutritivevalues. The Japanese have highlighted three conditionsthat define a functional food:

1. It is a food (not a capsule, tablet or powder) derivedfrom naturally occuring ingredients.

2. It can and should be consumed as part of the daily diet.3. It has a particular function when ingested, serving to

regulate a particular body process, such as:● Enhancement of the biological defense mechanism● Prevention of a specific disease● Recovery from a specific disease● Control of physical and mental conditions● Slowing the aging process”

As described earlier, phospholipids are added to mostfood products as food additives in small quantities be-cause of their technological functions. Simple raising ofthe quantity should on the one hand give the technologyeffect needed and on the other hand the nutritional bene-fit wanted.

However, it is not as simple as that. Even though phos-pholipids seem to be ideal candidates for functional food,there are some problems to overcome and some rules toobserve, mainly because of the problems linked to rela-

Eur. J. Lipid Sci. Technol. 103 (2001) 98–101 Phospholipids for Functional Food 99

Fig. 1. Phospholipid structure and type of phos-pholipid.

tively high quantities needed to achieve the preventive orcurative effects wanted. Only careful and clever formula-tion strategies would overcome the texture and viscosityproblems linked to the relatively high phospholipid con-centration. Another, and probably even more severe prob-lem, is the sensitivity of natural phospholipids to hydroly-sis. Most food products contain relatively high amounts ofmoisture and as a result such phospholipid-containingproducts develop a strong metallic to bitter off-taste be-cause of liberation of free fatty acids from the phospho-lipid backbone.

It is almost impossible to give recommendations how tocope with these aspects in general. But it can be said thatclever formulation strategies together with the right selec-tion of phospholipid fractions, good flavouring and some-times microencapsulation techniques can finally result inperfectly acceptable Functional Food products. It wouldgo beyond the scope of this article to address all these as-pects in detail.

As a consequence of the problems mentioned only a fewfunctional food products are on the market already con-taining reasonable quantities of phospholipids and withsubstantiated nutritional benefits.

What are the types of food suitable forphospholipid addition?

A first category of products with relatively low moisturecontent which additionally are relatively unsensitive forthe typical taste of especially soy-derived phospholipidsare

● chocolate, chocolate fillings;

● cocoa spreads, other sweet spreads;

● bakery products.

These are typical examples for which the nutritional“added value” can be achieved by an “overdose” of theemulsifier phospholipid (lecithin).

A second category of phospholipid containing FunctionalFood are those products which originally do not needphospholipid addition for solving a technological problem.

Examples are:

● milk products (yoghurts, milk drinks),

● muesli bars,

● phospholipid drinks (liposomal, instant),

● chewing gums.

One type of formulation may be picked out as it seems tobe of special attraction to the industry.

Formulation of (liposomal) drinks

As widely known, in an aqueous environment phospho-lipids tend to form closed vesicular structures surroundedby membranes made from phospholipid double layers[12]. This “liposome” called organisation allows to entrapwater soluble substances in the aqueous core of the vesi-cles and to solubilize lipophilic material incorporated in-side the lipophilic domains of the membranes.

At a first glance, liposomes seem to be an ideal form ofpreparation for Functional Food drinks as they combine

● high tech image (marketing aspects),● allow solubilization of lipophilic material in water,● entrap/protect water soluble ingredients,● combine technological aspects with nutritional added

value from the phospholipids used for liposome formu-lation.

However, as already mentioned for other formulations, al-so here are some big challenges to consider when tryingto formulate this type of drinks.

The biggest problem of 10 years ago, the large scalemanufacture of high quality liposomes from reasonablyaffordable phospholipids using conventional productiontechnology, is solved.The same applies to physicochem-ical stability (flocculation and/or sedimentation) whichcould be overcome using appropriate formulation technol-ogy and a proper selection of the right type of phospho-lipids.

The great challenge, yet unsolved, is phospholipid hydro-lysis leading to unacceptable taste due to free fatty acidformation. Without going into detail, a few possibilitiesshould be mentioned how, not to completely solve but, toreduce these problems:

● selection of a proper pH-value,● selection of the right type of phospholipids and fatty

acid pattern,● gel-type proliposomal formulations and,

to date the only guaranteed way to success is the follow-ing:

● powder-type proliposomal formulations (e.g. so-calledkryosomes, produced by freeze drying technology inthe presence of the active to be entrapped and using akryoprotector, usually a carbohydrate)

Phospholipids enhance bioavailability of especially lipophilic nutrients

It has been proven for various substances that the righttype of phospholipids combined with the active substancecan enhance bioavailability dramatically, even up to 400% [13]! However, this again requires quite sophisticat-

100 Schneider Eur. J. Lipid Sci. Technol. 103 (2001) 98–101

ed formulation strategies together with a specifically de-signed type of phospholipid. Ideal candidates as activesare for example are all types of carotenoids. But the sameprinciple applies to a lot of other scarcely absorbablenutrients.

This combination strategy enables attractive formulationsespecially for functional food. It allows saving cost for the active substance by reducing it’s amount – a very important aspect for the calculation of highly cost sensi-tive food products.

Are phospholipids novel food?

To date there are – with one exception – no phospholipidson the market which should be considered as novel foodaccording to the EU Novel Food Regulations [14]. Allproducts marketed are of origins which have been in human food a long time before the enforcement of thenovel food regulation. The same applies to processing ofthese substances.

The only exception today is an egg phospholipid concen-trate which has been obtained from liquid egg yolk in anunconventional way with a separation process using anion exchange based destabilisation process of the eggyolk emulsion [15].

Conclusion

Phospholipids combine nutritional and technologicalproperties in a single substance class. This dual and syn-ergistic function makes them ideal candidates for use infunctional food. On the one hand they act as emulsifiers,surfactants or liposome forming substances. On the otherhand they exhibit a wide range of nutritional and even pre-ventive if not therapeutic activities. They have cholesterolreducing, liver protecting effects as well as brain improv-ing functions.

By increasing the dosage normally used for food applica-tions and observing some principle formulation rules onecan get the health benefits mentioned.

References

[1] L. N. Vauquelin: Ann. Mus. Hist. Nat. 18 (1811) 212.

[2] M. Gobley: Recherches chimiques sur le jaune d’oed. J.Pharm. Chim. (Paris) 9 (1846) 1.

[3] H. Bollmann: Verfahren zur Gewinnung des durch Auslau-gen von Ölsaaten oder deren Presskuchen mit einemGemisch aus Alkohol und Benzol oder Benzin enthaltenenLecithins. German Patent 382 912 (1921).

[4] E 322 – Lecithine, Amtsblatt Europ. GemeinschaftL 223, 30(1978).

[5] B. F. Szuhaj: Lecithin Production and Utilization. J. Am. OilChem. Soc. 60 (1983) 306–309.

[6] M. Schneider: Fractionation and Purification of Lecithin. In:Lecithin, Sources, Manufacture & Uses. Ed. B. F. Szuhaj,AOCS Press, Champaign (USA) 1989, pp. 109–130.

[7] J.T. Knuiman, A.C. Beynen, M.B. Katan: Lecithin Intake andSerum Cholesterol. Am. J. Clin. Nutr. 49 (1989) 266.

[8] C. S. Lieber, L. M. De Carli, K. M. Mak, C. I. Kim, M. A. Leo:Attenuation of Alcohol- Induced Hepatic Fibrosis by Polyun-saturated Lecithin. Hepatology 12 (1990) 1390–1398.

[9] G. Pepeu, I. L. Pepeu, L. Amaducci: A Review of Phos-phatidylserine Pharmacological and Clinical Effects. IsPhosphatidylserine a Drug for the Ageing Brain? Pharma-col. Res. 33 (1996) 73–80.

[10] B. Koletzko, S. Edenhofer, G. Lipowsky, D. Reinhardt:Effects of a Low Birthweight Infant Formula Containing Hu-man Milk Levels of Docosahexaenoic and Arachidonic acid.J. Pediatr. Gastroenterology and Nutr. 21 (1995) 200–208.

[11] J. Goldberg: Functional Food, Designer Food, PharmaFood, Nutraceuticals. Chapman & Hall, New York (1994),Foreword.

[12] D. Lichtenberg, Y. Barenholz: Liposomes: Preparation,Characterisation and Preservation. Meth. Biochem. Anal.33 (1988) 337–463.

[13] S. Leigh, M. L. S. Leigh: Pharmaceutical compositions andtheir uses. PCT Appl. WO 99/44642 (1999).

[14] VO (EG) Nr. 258/97: Über neuartige Lebensmittel undneuartige Lebensmittelzutaten.

[15] Novel Food – EC Regulation 258/97, NF-TEC-01: Applica-tion form for placing on the market of egg yolk phospho-lipids (1997).

Eur. J. Lipid Sci. Technol. 103 (2001) 98–101 Phospholipids for Functional Food 101