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The effect of dairy management and processing on quality characteristics of milk & dairy products

NEFG. The effect of dairy management and processing on quality characteristics of milk & dairy products. NEFG. NEFG. Gillian Butler 1 , Mette K. Larson 2 , Britta Rehberger 3 and Jacob H. Neilsen 2. NEFG. NEFG. NEFG. 1 Nafferton Ecological Farming Group, Newcastle University, UK

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The effect of dairy management and processing on quality characteristics of milk & dairy products

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  1. NEFG The effect of dairy management and processing on quality characteristics of milk & dairy products NEFG NEFG Gillian Butler1, Mette K. Larson2, Britta Rehberger3 and Jacob H. Neilsen2 NEFG NEFG NEFG 1 Nafferton Ecological Farming Group, Newcastle University, UK 2 Department of Food Science, Aarhus University, Denmark 3 Research Station Agroscope Leibefeld-Posieux, Switzerland

  2. Plan; work carried out under QLIF • Explaining milk quality characteristics • Pan European study considering dairy management and milk quality; Denmark, Sweden, Italy and UK • Feeding trial to improve winter milk (UK) • Processing and stability of ‘enriched’ milk (Switzerland) • Influence of management on detailed CLA profile (UK)

  3. 1) Milk composition Milk is recognised to be a valuable sources of protein minerals (especially Calcium) and vitamins . . . . but also contains fat and for years milk fat (butter & cream) was considered to be nutritionally undesirable High levels of saturated fats (SFA) increase; blood LDL (bad) cholesterol levels risk of heart disease

  4. Unsaturated fatty acids in milk Milk fat also contains 25-40% unsaturated fats; monounsaturated (MUFA) and polyunsaturated (PUFA) Some have positive effect on health (more later) The balance of ‘good’ & ‘bad’ fats in milk largely depends on dairy diets PUFA supply hydrogenation in rumen subsequent desaturation in udder Fresh forage (grazing) diets produce milk with higher levels of unsaturated fatty acids

  5. Nutritionally desirable PUFA Classed as omega 3 or omega 6 Omega 3 greater benefit essential for brain/nerve development heart/cardiovascular diseases α linolenic acid (αLA) main n-3 in milk Image from: http://www.supplementquality.com/news/fatty_acid_structure.html Conjugated linoleic acid (CLA) Reducing cancer risk Preventing heart disease Improving immune function Image from: http://www.raw-milk-facts.com/images/CLA_c9_t11.gif

  6. Antioxidants Milk also source of fat soluble vitamins & antioxidants Vitamin E in butter higher than most fruit and vegetables Carotenoid content of butter higher than many fruits 3 important functions protection against cell damage; cancer & heart disease in humans Improve health of dairy cows (reduced mastitis and improved fertility) Prolong shelf life of unsaturated fats

  7. 2) Farm survey - outline • Carried out in; Italy, Denmark, Sweden and UK • Clusters of 5 farms per management system • 5 systems compared in each country, including 2 organic or low input (1/4 in Sweden) • Bulk milk samples and management information collected throughout the year • Fatty acid & fat soluble antioxidant profiles determined

  8. Butler et al 2008 & Slots et al 2009 & Butler et al 2009 b

  9. Butler et al 2008 & Slots et al 2009 & Butler et al 2009 b

  10. Butler et al 2008 & Slots et al 2009 & Butler et al 2009 b

  11. Butler et al 2008 & Slots et al 2009 & Butler et al 2009 b

  12. Butler et al 2008 & Slots et al 2009 & Butler et al 2009 b

  13. Key Diet: GRAZ grazing G SIL grass silage HAY hay M SIL maize silage CONC concentrate feeds Individual fatty acids: CLA9 CLA C18:2 c9t11 α LA alpha linolenic acid VA vaccenic acid (precursor for CLA) OA oleic acid CLA10 CLA C18: c0 c12 TOTAL N-6 total omega 6 FA Butler et al 2009 b

  14. Key Diet: GRAZ grazing G SIL grass silage HAY hay M SIL maize silage CONC concentrate feeds Constituents: Fatty acid groups SFA Saturated fatty acids MUFA Monounsaturated fatty acids PUFA Polyunsaturated fatty acids α tocopherol or vitamin E RRR natural isomer 2RS synthetic isomer Carotenoids B CAR β catotene LUT lutein ZEA zeaxanthin Butler et al 2009b

  15. 3) Improving milk fat on winter diets • Fresh herbage improves fatty acid (FA) profile in milk • Limitation to herbage production (cold or dry) • Milk quality poorer on conserved forage, especially maize silage • Feeding oilseeds can raise PUFA concentrations in milk • Two parallel herds (conventional and organic) 3 diets: • Control • Linseed (α LA) • Rapeseed (oleic acid)

  16. Supplementation trial - Results • α LA content higher in organic milk (p<0.001) • Linseed increased α LA and CLA9 (p<0.001) • Rapeseed increased CLA9 (p<0.001) but not α LA • Significant interaction (p=0.003) identified between management and supplementation for α LA Butler unpublished

  17. 4) Processing & storage of healthy milk fat • Assessing processing procedures for dairy products • Fermentation of cream and churning to butter • Feeding oilseeds to enrich milk fat (increase PUFAs) • Assessing stability and sensory quality of raw material and end products • 8 weeks @ 8°C • Challenged with; UV light, heating and oxidation • Using GC-O and sensory methods to characterise aroma • GC/MS/O detecting oxidation rates

  18. Results – i) processing • Significant differences in total CLA content between cream from convention and organic milk • Butter from fermented cream (both conventional and organic) no significant change in CLA content

  19. Results – ii) stability & storage • Enriched butter elevated PUFA but also antioxidants • Enriched butter more spreadable • Both butters had similar: • flavour profiles after storage • odour compounds after storage • Little change in fatty acid profiles during storage • Levels of α tocopherol (antioxidant) declined with time (Mallia et al 2009)

  20. 5) Detailed CLA profiles • 14 known isomers, dominated by C18:2 c9t11 - CLA9 • Range in physiological functions in man and dairy cows – not always beneficial • Mostly synthesised by rumen hydrogenation also desaturation in udder; CLA9 (largely) & C18:2 t7c9(totally) • CLA isomer concentrations compared in milk form 3 management systems: (UK) • Conventional • Low input organic certified • Low input not certified

  21. 0.5  c11t13 FF t12t14   t11c13 t11t13  t6t8  c/t12,14   t8c10 1.5 -1.5 c9t11  t7t9  t9t11  CF  t8t10  c10t12  t10c12 t7c9  CON -0.5 CLA isomers and management • CLA isomers cluster into 3 groups • CLA9 >80% total • Only some isomers influenced by feeding system • Link to fresh forage in diet Butler et al (2009a)

  22. Conclusions • Fresh forage in dairy diets raises concentration of beneficial fatty acids in milk fat • Organic & low input dairy production relies on higher forage intakes • αLA concentrations in milk consistently higher if produced under organic management • Elevated concentrations of CLA9 in milk fat survive fermentation and processing to butter • Higher concentrations of PUFA in milk may not always compromise oxidative stability • Not all isomers of CLA respond to changes in dairy nutrition

  23. Acknowledgements We gratefully acknowledge funding from the European Community financial participation under the Sixth Framework Programme for Research, Technological Development and Demonstration Activities, for the Integrated Project QUALITYLOWINPUTFOOD, FP6-FOOD-CT-2003- 506358.

  24. References BISIG, W., EBERHARD, P., COLLOMB, M. & REHBERGER, B. (2007) Influence of processing on the fatty acid composition and the content of conjugated linoleic acid in organic and conventional dairy products - A review. Lait, 87, 1-19. BUTLER, G., COLLOMB, M., REHBERGER, B., SANDERSON, R., EYRE, M. & LEIFERT, C. (2009a) Conjugated linoleic acid isomer concentrations in milk from high- and low-input management dairy systems. Journal of the Science of Food and Agriculture, 89, 697-705. BUTLER, G., NIELSEN, J. H., LARSEN, M., REHBERGER, B., STERGIADIS, S., CANEVER, A. & LEIFERT, C. (2009b) The effects of dairy management and processing on quality characteristics of milk and dairy products NJAS Wageningen Journal of Life Science, Special issue: Improving Production Efficiency, Quality and Safety in Organic and “Low-Input” food supply chains. BUTLER, G., NIELSEN, J. H., SLOTS, T., SEAL, C., EYRE, M. D., SANDERSON, R. & LEIFERT, C. (2008) Fatty acid and fat-soluble antioxidant concentrations in milk from high- and low-input conventional and organic systems: seasonal variation. Journal of the Science of Food and Agriculture, 88, 1431-1441. MALLIA, S., PICCINALI, P., REHBERGER, B., BADERTSCHER, R., ESCHER, F. & SCHLICHTHERLE-CERNY, H. (2008) Determination of storage stability of butter enriched with unsaturated fatty acids/conjugated linoleic acids (UFA/CLA) using instrumental and sensory methods. International Dairy Journal, 18, 983-993. SLOTS, T., BUTLER, G., LEIFERT, C., KRISTENSEN, T., SKIBSTED, L. H. & NIELSEN, J. H. (2009) Potentials to differentiate milk composition by different feeding strategies. Journal of Dairy Science, 92, 2057-2066.

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