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Functional lipids in beverage products

30 June 2016  •  Author(s): Guillermo E. Napolitano, PhD, Expert Scientist, Nestlé Development Center

The last decade has witnessed an extraordinary surge in the development of beverage products containing healthier oils and nutritionally active lipid ingredients. There has been a significant shift from the use of relatively unhealthy, but chemically stable, fats rich in saturated and trans fatty acids (TFA), to healthy and chemically unstable oils rich in unsaturated fatty acids. As a consequence, research resources also shifted from the more conventional aspects of the physico-chemical properties of bulk fats to more complex problems of lipids oxidation in bulk, disperse phases and oil in water emulsions1,2.

Functional lipids in beverage-products

 

Since the implementation of mandatory labeling of TFA in packaged foods and beverages in the USA in 2006, more than 2 million tons of soybean oil have been lost or diverted from partial hydrogenation to other uses. The US Food and Drug Administration estimates that between 2003 and 2012 the content of TFA in foods has been reduced by 78%. The most recent decision to remove the GRAS status of PHO (preliminary determination in 2013 to be effective in June 2018) will further accelerate the transition to alternative oils3 . The new focus is – and will continue to be – incorporating the ‘good’ rather than eliminating the ‘bad’ fats and oils.

Opportunities and challenges for functional lipids

There are significant challenges involved in the development of a beverage containing healthier or functional lipids that will maintain all the necessary sensory attributes. The most critical single hurdle for the development of beverages containing healthier oils is achieving oxidation stability, especially in products with long expected shelf lives stored at ambient conditions.

To incorporate healthier and or functional lipids in beverages – basically adding oil and specific lipid compounds to water based products – it is necessary to address the following technological challenges:

A) Physical stabilisation of fine suspensions and oil in water emulsions

  • Emulsion and fine dispersions need to be stabilised by effective food emulsifiers and stabilisers preferentially by ‘natural’ (label friendly) ingredients and additives
  • Develop process and engineering solutions as alternatives to chemical emulsifiers and stabilisers.

B) Chemical stabilisation of flavour and colour in emulsions

  • Incorporate ‘natural’ lipid antioxidants acting individually or combined in a synergetic mode
  • Find ‘natural’ metal chelators as effective as, but better perceived than, EDTA (ethylenediaminetetraacetic acid)
  • Preserve native antioxidants present in unrefined or mildly refined oils
  • Design engineering solutions as alternatives to the addition of oil antioxidants (e.g., handling, packaging and processing).

Lipids as functional ingredients for RTD beverages

Adding healthy and functional ingredients has become very common over the last few years. Lipids with potential relevance, or currently being used for functional beverages, are listed in Table 1 (below). A review of new and emerging oils has been previously published4.

Table 1

Lipid

Benefits/ constituents

Main sources

Fatty Acids

Alpha-linolenic acid (ALA, 18:3n-3)

Essential n-3 fatty acid

Flax seed, chia, kiwifruit seed, walnut oil, canola oil, soybean oil

Arachidonic acid (AA, 20:4n-6)

Conditionally essential n-6 fatty acid. Nervous system development and function

Fungal lipids (Mortierella alpina), animal fat/ oil sources

Conjugated linoleic acid (CLA, i.e., cis-9, trans-11,18:2 and trans-10,cis-12, 18:2)

Weight control, anti-cancer (controversial claims)

Grass-fed ruminant fat, chemically derived from safflower oil

Docosahexaenoic acid (DHA, 22:6n-3)

Conditionally essential n-3 fatty acid, eye, brain development and health, cognitive performance.

Marine oils (fish, algae). Agricultural sources are under development.

Eicosapentaenic acid (EPA, 20:5n-3)

Conditionally essential n-3 fatty acid, angio- and cardio- protective.

Marine oils (fish, algae). Agricultural sources are under development.

Gamma-linolenic acid (GLA, 18:3n-6)

Skin health

Black currant, evening primrose seed, borage seed, and hemp seed oils

Stearidonic acid (SDA,18:4n-3)

Metabolic precursor of EPA and DHA.

Echium spp. and black currant seed oils, transgenic soybean oil

Marine Oils

Marine oil (rich in EPA, DHA, astaxanthine, choline)

Cardiovascular, eye, brain and cognitive health and development.

Fish and krill oils

Marine phospholipids

Brain and cardiovascular health.

Marine fish, microalgae and crustacean

Sterols

Mixed phytosterols

Angio- and cardio-protective

Vegetable oils 

 

Carotenoids

β-carotene

Pro-vitamin A, lipid antioxidant (and anti-photo-oxidant)

Crude and red palm oils, various plants, synthetic

Lutein

Eye function and health, skin protection.

Marigold flowers

Lycopene

Anti-carcinogenic (prostate cancer)

Tomatoes, watermelon

 

Vegetable Oils

Red palm oil

Source of tocopherols, tocotrienols, and β-carotene

Crude and mildly refined palm oil

Rice bran oil

Angio- and cardio-protective, rich in gamma-oryzanol

Rice bran oil (also in corn and barley oils)

 

Lipid Soluble Vitamins

Vitamins A, E, D and K

Essential nutrients

various sources

Structured Lipids

Medium chain triacylglycerol (MCT)

 

Enhanced bioavailabity of energy from fatty acids, brain metabolism (clinical trials ongoing)a

Chemical interesterification of  glycerol with hydrolyzed and distilled lauric oils (coconut and/or palm kernel oils)

 

Other Lipids

Capsiate

Weight management and satiety

Fruits of Capsicum spp. (chili peppers)

Ceramides

 

Skin health

Umbelifera seed oils

Egg lecithin (rich in choline and AA)

Brain health and development

Eggs

* Effects of Triglycerides on Age-Related Cognitive Function Decline in Older Subjects https://www.clinicaltrials.gov/ct2/show/NCT01702480?term=NCT01702480&rank=1

Nutritionally active lipids include oils rich in n-3 and n-6 polyunsaturated fatty acids (PUFA, popularly known as ‘omega 3’ and ‘omega 6’ oils respectively), sterols, pigments, liposoluble vitamins, and ‘structured’ synthetic lipids. Each of those lipids may have potential health benefits. Health claims related to the benefit of the lipids listed below may or may not be clinically proven or fully substantiated and their possible beneficial effects will depend on factors such as the dose, target population, and source of the ingredient. Furthermore, the regulatory aspects regarding ‘allowed claims’ and ‘usage’ vary in the different countries.

The bioactive lipids in Table 1 must not be considered as common ingredients and simply added to products with the expectation of the claimed benefits. It is the work of the specialists and nutritionists to advise about sources, dosages and interactions with other ingredients and processes. 

Some claims are supported by solid or mounting evidence (e.g., lipid soluble vitamins, n-3 PUFA), while other claims are less substantiated and even speculative (e.g., CLA, capsiate). Regardless of evidence showing that consuming fruits and vegetables have beneficial health effects, many studies failed to demonstrate positive health benefits of consuming plant extracts, such as purified carotene and ‘antioxidants’5.This suggest that many bioactive compounds may be beneficial only when consumed as part of unprocessed foods.

Functional lipids in beverages

Among the most widely used functional lipids in beverages are long chain n-3 (omega 3) polyunsaturated fatty acids (LC-PUFA). A recent search in BevNet.com for ready to drink (RTD) products presents numerous examples. The presence of many beverages with added n-3 LC-PUFA is not surprising when considering the massive evidence for their central role in health maintenance and disease prevention. Considering that dietary intake of LC-PUFA in the western and west influenced diets are reaching historically low levels, their addition to foods and beverages will likely be a sustained trend. Conventional sources of n-3 PUFA are marine oils, which in turn are compromised by sustainability and environmental contaminant concerns, as well as by shortages of supply given that a large portion of n-3 LC-PUFA rich marine oils are utilised as feed in the aquaculture sector. In this regard, agricultural sources of EPA and DHA currently under development4 will be welcome.

From the food technology perspective, the major challenge for the incorporation of n-3 LC-PUFA is the flavour deterioration due to lipid oxidation. Solving this problem requires significant advances in lipid anti-oxidation and protective packaging systems.

There are four nutritionally relevant n-3 fatty acids from various sources available as functional ingredients for foods and beverages (Table 1, above). Each of these n-3 fatty acids are associated with particular health benefits and claims.

Alpha-linolenic acid (ALA, 18:3n-3) is an essential fatty acid in the classical sense and today is the only one available from agricultural commodity sources, such as flax seed, Canola (rapeseed) and soybean oils. The health benefits of ALA are limited due to a very slow conversion rate in the body to the more bio-active LC-PUFA (EPA and DHA). It is believed that this slow conversion rate does not match the high requirements of n-3 LC-PUFA during fetal and infant brain development6.

For that reason, EPA and DHA are the most nutritionally active n-3 fatty acids that can be directly and rapidly incorporated in to the target tissues, or become the substrate for further metabolic transformations7,8. The most common source of EPA and DHA is fish oil. ‘Single cell oil’ sources (from microalgae) produced heterotrophically by fermentation are common now and have significant advantages over the conventional fish sources in terms of sustainable production and supply – and as a preferred vegetarian choice.

Stearidonic acid (18:4n-3) has some metabolic advantages over ALA (faster conversion to EPA). The health benefits of SDA from Echium and blackcurrant seed oils is an emerging field of research and application in beverages. An alternative agricultural source of SDA from transgenic soybeans has been recently developed.

Most of the RTD products containing n-3 PUFA commercially available offer a modest amount, between 30 and 50mg of combined EPA + DHA per serving, which is 5-10% of the consensus recommended daily allowance (RDA). Attempts to increase the amount of n-3 PUFA in beverages face difficult challenges of flavour stability due to lipid oxidation.

Other nutritionally active lipids for RTD products

Besides n-3 PUFA, many of the other lipids presented in Table 1 (above) also found their way into functional beverages. A BevNet.com web search of bioactive lipids available in the USA includes: lipid soluble vitamins, phytosterols, carotenoids, ceramides, MCT, GLA and CLA.

Some bioactive lipids used in foods were not found in RTD products. Those include ARA, capsiate and rice bran oil. These lipids represent potential opportunities for RTD that require exploration.

Soy Lecithin is universally used as an emulsifier and it is somewhat negatively perceived as a food additive and automatically linked to products from transgenic (GM) sources and allergenicity. For that reason, the well-known nutritional benefits of lecithin (and choline) are not properly utilised in foods and beverages. Alternative lecithin sources from non-GMO, such as sunflower and canola oils, are available.

Tocotrienols are recent additions to the tool box of bioactive lipids, but regulations in some countries restrict their use to nutritional supplements only. Red palm oil is used in the formulation of prepared foods, baked products and confections, but it has not yet found its way as an ingredient in RTD products. This oil is a natural carrier of phytonutrients providing tocotrienols, tocopherols and β-carotene in a mildly refined wholesome oil. The strong red/yellow colour of this palm oil is a deterrent for its use in many applications, but it may be an asset in fruit and vegetable juices.

The amounts of functional ingredients, such as antioxidants, vitamins and carotenoids, represent a larger proportion of the corresponding RDAs (25-100%) compared to that of added n-3 LC-PUFA (5-10%).

Conclusions

Adding healthy oils and nutritionally active lipids to RTD products is a timely and challenging opportunity. The main hurdles of incorporating functional lipids in RTD products are those related to the chemical and physical stabilisation of the product. Most functional lipids are reactive and need to be protected by lipid antioxidants or by elaborated delivery systems. An increase in the types and amounts of functional lipids that could be added to beverages will require significant advances in our understanding and application of lipid antioxidant systems for oil in water emulsions.

There are many types of suitable functional ingredients with potential health benefits and claims. Out of the two dozen presented in this report, only a few of them have substantiated or clinically proven benefit. In other cases, as with the many compounds classed under the blanket term ‘antioxidant’, benefits are not well substantiated. The development of beverage formulations with functional lipids should focus on those ingredients with expected long term sustainable health claims.

About the author

Guillermo NapolitanoDr. Guillermo E. Napolitano graduated from the Facultad de Ciencias Exactas y Naturales of the Universidad Nacional de Buenos Aires (Licenciado in Biológicas Sciences). He obtained a MSc and PhD from Dalhousie University, Halifax, Canada, specialising in marine lipids under the direction of Prof. Emeritus Robert G. Ackman. Dr. Napolitano has extensive experience in the fields of analytical chemistry, biochemistry and technology of fats and oils and has numerous publications in the area of marine oils and technology of lipids. His current research focus is on the relationship between structure and function of lipids in foods, specialising in beverages, confections and culinary applications. He is an Expert Scientist in the Department of Science and Technology at the Nestlé Development Center in Marysville, Ohio, USA.

References

  1. Yi, J., Dong, W., Zhu, Z., Liu, N., Ding, Y., McClements, D.J. and Decker, E.A. (2015). Surfactant Concentration, Antioxidants, and Chelators Influencing Oxidative Stability of Water‑in‑Walnut Oil Emulsions. Journal of the American Oil Chemical Society. 92:1093–1102
  2. McClements, D. J. and Decker, E. A. (2000). Lipid Oxidation in Oil-in-Water Emulsions: Impact of Molecular Environment on Chemical Reactions in Heterogeneous Food Systems. Journal of Food Science 65 (8)
  3. Federal Register, Vol. 80, No. 116 / June 17, 2015 / Notices. Final Determination Regarding Partially Hydrogenated Oils Partially Hydrogenated Oils, pp. 34650-34670
  4. Napolitano, G. E. (2012). New and emerging sources of vegetable fats and oils. New Food 15 (6): 56-59
  5. Cook, N.R., Albert, C. M., Gaziano, J. M., Zaharris E., MacFadyen, J., Danielson, E., Buring, J.E., Manson, J. E. A. (2007). Randomized factorial trial of vitamins C and E and beta-carotene in the secondary prevention of cardiovascular events in women: results from the Women’s Antioxidant Cardiovascular Study. Archives of Internal Medicine 167 (15):1610-8
  6. Goyens, P.L., Spilker, M.E., Zock, P.L., Katan, M.B. and Mensink, R.P. (2005). Compartmental modeling to quantify alpha-linolenic acid conversion after longer term intake of multiple tracer boluses. Journal of Lipid Research 46:1474–83
  7. Calder, P.C., Yaqoob, P. (2009). Omega-3 polyunsaturated fatty acids and human health outcomes. Biofactors 35(3):266-72
  8. Swanson, D., Block, R., and Mousa, S. A. (2012), Omega-3 Fatty Acids EPA and DHA: Health Benefits Throughout Life. Advances in Nutrition 3 (1):1-7

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