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New and Emerging Technologies: Redefining Natural Colour
Reformulation and Applications
Dr Jim Bullock - iFormulate Ltd
Food Matters Live
London, November 2014
+44 7450 436515
www.iformulate.biz
But First, a Little About Us…
Dr Jim Bullock E: [email protected] M: +44 (0)7450 436515
Dr David Calvert E: [email protected] M: +44 (0)7860 519582
www.iformulate.biz [email protected]
iFormulate: founded by two experienced industry professionals
• Diverse experiences, knowledge and network:…polymers, materials science, chemistry, imaging, dyes, pigments, emulsion polymerisation, biocides, anti-counterfeiting, environmental, formulation, consultancy, marketing, business development, strategy, regulatory, training, events, R&D, innovation…
• Clients large and small across different industries which use formulation technology, providing/developing new ideas, helping commercialise technologies, project building, consultancy, workshops, contacts and training.
• …pharma, food, cosmetics, detergents and cleaners, coatings, inks, agrochemicals, disinfection etc…
• Benefit from translation opportunities from one industry to another Open Innovation Roadshows
• Supporting major UK initiatives in formulation science and technology
Natural Colours: How Do They Compare to Synthetic Colours?
Natural Colours…
• Are less brilliant
• Have lower colour strength
• Have narrower colour gamut
• Are less stable to…everything: Temperature, light, pH, oxygen…
• Are difficult to characterise, purify and process
• Are not designed
• …may be obtained sustainably from waste streams in F&B
Synthetic Colours…
• Have precisely designed physical and colouristic properties
• …have an image problem and are candidates for substitution
Know Your Colour: What Have You Got?
Understanding the
chemical features of
natural colours that
cause instability
Warning: These slides may
feature some chemistry!
How can Colour be Destroyed, Changed or Degraded?
Heat • Heat accelerates most chemical reactions
Light • Photocatalysis: Photons of light may have a catalytic effect
pH • Excess of H+ ions (low pH) or OH- ions (high pH) may accelerate
reactions such as hydrolysis
Oxidation or reduction • Oxidising or reducing agents may attack certain chemical bonds
Chemical interactions • Catalysis by e.g. impurities, metals
Physical interactions • Aggregation of particles, solubilisation, precipitation of molecules
Know Your Colour: Anthocyanins • Glycosated (sugar) derivatives of
anthocyanidin
• 6 anthocyanidins and 400 anthocyanins identified in plants
• Shade changes with –OH /-OCH3 substitution (auxochromic effect)
• Significant effect of pH on colour
Images: Ananga et al 2013 “Production of Anthocyanins in Grape Cell Cultures” in “The Mediterranean Genetic Code - Grapevine and Olive” (Sladonja (Ed.) at www.intechopen.com/books/
Know Your Colour: Carotenes and other Carotenoids
• Terpenoid – long polyene conjugated chain which is the chromophore
• Subtle changes to shade via substituents on terminal rings (auxochromic effects)
• Chain may degrade oxidatively in heat or light, and be unstable in acids
• Hydrocarbon –water insoluble, fat soluble
Beta-carotene
Alpha-carotene
Lutein (a xanthophyll)
Zeaxanthin (a xanthophyll)
Lycopene
Know Your Colour: Chlorophyll
• Porphyrin (chlorin) ring provides conjugated system (chromophore) with similar structures seen elsewhere in nature (haemoglobin) and in synthetic colorants (phthalocyanines).
• Central metal ion affects shade (auxochromic effect)
• Cu/Na chlorphyllin: Cu replaces Mg in ring and Na salts of carboxyl groups.
• Acid instability: Removes Mg ion and hydrolyses ester chain
• Alkali instability: Hydrolysis of ester chain.
• Heat accelerates this decomposition
Chlorophyll a Chlorophyll b
Alkali breakdown products:
Know Your Colour: Curcumin • Diarylheptaniod: Two aromatic rings joined by
π conjugated carbon chain • Shade affected by:
– tautomeric forms (enol is more stable) – minor components: derivatives with one or
both OCH3 groups missing • Unstable to light, alkali • Stable to heat • Insoluble in water (acid-neutral), soluble in
alkali • Slightly soluble in vegetable oil
FAO Chemical and Technical Assessment 2004
pKa = 7.8
pKa = 8.5
pKa = 9.0
Keto – Enol tautomerism
Know Your Colour: What Have You Got?
Natural colours are not just clean single molecules:
• Mixtures of colour, other non-coloured material
• Full of impurities with closely related structures (analogues)
• Generally poorly characterised
Stability: Some Approaches from F&B
Case Study: Curcumin • Stabilisation: Complex with divalent metal ions
– B.Zebib et al Bioinorganic Chemistry and Applications Vol 2010, Article ID 292760
• Mechanical mixing of curcumin with metal salts, extraction with water/glycerol mix
• “they are able to protect curcumin against chemical degradation in neutral and basic media for along period of time“
Case Study: Anthocyanin Lakes • Keracol: www.keracol.co.uk
• Colours extracted from natural plant materials, extraction and purification
• Claiming lake pigment formed using novel “biomimicry” process
• Marketed for cosmetics, naturally derived hair dyes and other areas
www.keracol.co.uk/applications#!__products-available
Case Study: Anthocyanin Lakes
Nestec/Nestle: World Patent Application 2014/023712
Example 1: Preparation of a spray-dried blue colouring composition with red cabbage extract and tannic acid.
• Red cabbage extract diluted into water and cooled , sodium acetate added and pH adjusted to 5.5
• Ferrous sulphate heptahydrate added, tannic acid added
• Maltodextrin dissolved into mixture and pasteurized. Cooled and spray dried to a powder.
• Retains blue colour at pH < 7, unlike non-stabilized extract.
• Simulated daylight exposure shows better light fastness
Other examples using e.g. aluminium sulphate, other anthocyanin extracts, freeze drying • “The resulting SMARTIES® sweets had an attractive blue
colour which did not fade perceptibly during several months' storage in daylight…The colouring composition…can therefore be used to colour foods…
Why Encapsulate? • Stability (chemical, heat, light…) • Formulation compatibility • Controlled release • Taste masking Encapsulation can be • Molecular
Cyclodextrins, Calixarenes, Zeolites, Metal organic frameworks etc
• Nano • Micro • Macro
Stability Challenges Industry Solutions: Encapsulation:
Photo: Idea go / freedigitalphotos.net
Case Study: Curcumin and Bixin Interaction of Curcumin and Bixin with β-Cyclodextrin: Complexation Methods, Stability, and Applications in Food Marcolino et al, J. Agric. Food Chem.2011, 59, 3348–3357
Curcumin: 1:2 Complex
Bixin: 1:1 Complex
“Complexation of colorants with β-CD promoted an intensification of color and increased water solubility; however, stabilization in the presence of light occurred only for bixin”
Case Study: Microemulsions
• Unlike conventional emulsions, microemulsions are thermodynamically stable
• Particle size 10-50nm, “Swollen micelle” structure with surfactant close-packing
• Careful surfactant choice to optimise microemulsion
• Examples of microemulsions to “solubilise” colours in aqueous systems and reduce sensitivity to light
Internal oil phase
Surfactant
Co-surfactant
Mohamed Awad Saad Abd El Galeel, PhD Thesis, University of Bonn, 2002
Stability: Some Approaches from outside F&B
• Phospholipids (synthetic or natural) - hydrophilic (phosphate group) and fatty hydrocarbon tail.
• Self-association in solution bilayers, micelles and liposomes.
• Used e.g. for. encapsulation and stabilisation of sensitive drug molecules to permit stability during oral delivery - low pH in GI tract would normally degrade peptide active ingredients
Nanoencapsulation with Lipsomes: Use in Cosmetics and Drug Delivery
Image : Sætern, Parenteral Liposome and Cyclodextrin Formulations of Camptothecin, PhD thesis University of Tromsø 2004 http://en.uit.no
Indigo@Silicalite: a New Organic−Inorganic Hybrid Pigment “In the search for stable and enduring organic colors, we have combined indigo, a historical and industrially important chromophore, with silicalite, the MFI zeolite. The resulting pigment presents high color durability against most external agents (e.g., light, temperature). This stability and its physical properties are explained by the association of indigo with an inert mineral, which is also influenced by formation conditions such as the initial indigo concentration and the thermal treatment.” Dejoie et al, ACS Appl. Mater. Interfaces, 2010, 2 (8), pp 2308–2316 and Applied Spectroscopy 64, 10 (2010) 1131-1138
Image: www.intechopen.com
Molecular Scale Encapsulation: Example - Zeolites
Molecular Scale Encapsulation - 1200 Years Ago Maya Blue (800AD): Indigo – Sepiolite or Palygorskite
Giustetto et al J. Phys. Chem. C2011, 115, 16764–16776 De Bonampak al Templo Mayor by Constantino Reyes-Valerio from http://www.azulmaya.com/en/
Summary
• Natural colours “as is” have severe drawbacks in F&B applications
• Know your colour: Understanding chemical and physical mechanisms of instability is first step
• Protection mechanisms such as “lake” pigments and encapsulation (molecular, nano, micro…) can provide stability benefits to natural colours
• Look at protection solutions from outside F&B
Dr Jim Bullock E: [email protected] M: +44 (0)7450 436515
www.iformulate.biz [email protected]