Fachtagung - ETH Zurich, May 5th2009
Sweet cream UFA/CLA butter and CONV butter were stored for 8 weeks at 6 °C.
►Fatty acid composition was determined using high resolution gas chromatography (HRGC) (1).
►CLA isomers were analysed by Ag+-HPLC (2).
►Aroma compounds were extracted using headspace solid phase microextraction (HS- SPME) combined with gas chromatography/mass spectrometry/olfactometry (GC/O).
1
Agroscope Liebefeld-Posieux Research Station ALP, Switzerland;
2Institute of Food Science and Nutrition, ETH Zurich, Switzerland silvia.mallia@alp.admin.ch
S. Mallia
1,2*, U. Wyss
1, M. Collomb
1, F. Escher
2, H. Schlichtherle-Cerny
1Unsaturated fatty acids (UFA) and conjugated linoleic acids (CLAs) are natural components of milk fat from ruminants.
Their content can be further increased to obtain dairy products with a higher nutritional value and potential beneficial effects. On the other hand, UFA are susceptible to oxidation.
An enrichment of UFA/CLA in milk is achieved by supplementing the animal diet with plant or fish oils or with oleaginous seeds (1).
The different diets influenced the FA composition of butter.
The addition of sunflower seeds resulted in a significant increase of UFA, including CLA.
Total CLA was 2.050 g/100 g fat in UFA/CLA butter and 1 g/100 g fat in CONV butter.
The CLA isomers cis-9 trans-11, trans-7 cis-9 and trans-10, trans-12 are significantly higher in UFA/CLA enriched butter.
__________________________________ Results __________________________________
Bibliography____________________________________
1. Collomb, M., Sollberger, H., Bütikofer, U., Sieber, R., Stoll, W., & Schaeren, W. (2004). IDJ, 14, 549-559.
2. Collomb, M., Sieber, R., Bütikofer, U. (2004). Lipids, 4, 355-364.
Influence of a pasture-based diet supplemented with sunflower seeds on fatty acid composition and aroma profile of butter
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The supplement of sunflower seeds resulted in a significant lower content of saturated fatty acids and a higher concentration of monounsaturated (MUFA) and polyunsaturated fatty acids (PUFA), including conjugated linoleic acids (CLA), in the enriched butter.
►
UFA/CLA enriched butter did not elicit strong off-flavours after cold storage (6 °C), as may be expected from the higher UFA content.
►This result can be explained by the higher α-tocopherol content in UFA/CLA enriched butter, which probably acts as antioxidant.
Fatty acid composition
The two fresh butter types are characterised by creamy (diacetyl), milky (2-nonanone) and soapy (nonanal) notes.
After storage UFA/CLA butter showed stronger cheesy (butanoic acid), fatty (heptanal) and green (hexanal, trans- 3-hexenol) odour compared to CONV butter.
The intensities of metallic/oxidised notes were similar in the two kinds of butter.
Odour profile
Composition of the diet supplemented with a sunflower seeds/bran mixture and control diet (daily intake, kg DM/d per cow)
The experiment was carried out at ALP in May and September 2006.
Two groups of cows (10 for each group) were fed different diets for 14 days.
nd = not detected
*P<0.05, **P<0.01
**P<0.01
Grass Maize silage
Sunflower brand mixture
Concentrate Minerals
Group I pasture 0 1.6 0.6 0.3 Group II pasture 5.7 0 1.4 0.3
1 10 100 1000 10000
t11 c13t10 c12 c9 t11 t8 c10 t7 c9 t10 t12 t9 t11 t7 t9 total CLA
mg 100 g-1 fat
UFA/CLA CONV Fatty acid UFA/CLA CONV
Oleic acid ** 24 17 Linoleic acid * 1.6 1.2 α-Linolenic acid 0.45 0.50
CLA ** 2 1
Sum saturated** 50 60
Sum unsaturated** 42 29 Sum polyunsaturated* 6 4 Trans total without CLA t** 9 5 Sum Omega 3 0.96 0.98
Sum Omega 6* 3.2 2.2
Fatty acid composition (g/100 g fat) of UFA/CLA and CONV butter
Selected CLA isomers and total CLA in UFA/CLA and CONV butter
Compound Odour descriptor
Fresh Stored UFA/CLA CONV UFA/CLA CONV Diacetyl creamy ++ ++ + + Butanoic acid cheesy + + +++ ++
Hexanal green + + +++ ++
trans-3-Hexenol green/oily + nd +++ +
Heptanal fatty + + +++ ++
2-Nonanone milky ++ ++ ++ ++
Nonanal soapy ++ ++ + +
δ-Decalactone fruity + + +++ ++
1-Octen-3-one metallic + + ++ ++
(E,E)-2,4-nonadienal oxidised nd nd ++ ++
Odour-active compounds of fresh and stored (8 weeks at 6 °C) UFA/CLA and CONV butter
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Introduction
►Study of butter enriched in UFA/CLA by supplementing the animal diet with sunflower seeds.
►Comparison of fatty acid (FA) profiles, CLA isomers and aroma composition of UFA/CLA enriched butter to that of conventional butter (CONV).
Objectives
Materials and methods
Feeding experiment
Group I:
diet supplemented with sunflower seeds.
Group II:
control diet (maize silage).
**P<0.01
