Last updated on August 17, 2023
This study is the first in the literature to show a significant relationship between fatty acids and butter color and to say that fatty acids can affect the color of butter.
Halil Ibrahim AKGUL1, Mustafa SENGUL2
1Bayburt University, Food Engineering Department, Bayburt, Turkey
2Ataturk University, Food Engineering Department, Erzurum, Turkey
3rd International Conference on Advanced Engineering Technologies, 19-21 September 2019
In this study, physicochemical properties and fatty acid profile of 30 butter samples were studied and the relationship of these parameters with the color of butter was investigated. Statistically significant correlations were found between the color of butter and dry matter, fat, salt ratio, peroxide value, polenske value and C6:0, C8:0, C10:0, C14:0, C14:1, C18:0, C18:1 and C18:2 fatty acids.
Keywords; Butter color, fatty acid, statistics
The natural yellow color of butter mainly results from carotene dissolved in the fat, which originates from the feed and together with the characteristic microstructure of well-worked butter . The yellow color of butter carries consumer perceptions of “fresh grass-feeding” [2, 3].
Previous studies [1, 4-9] have suggested that many factors such as vitamin A, vitamin E content, season, processing, storage time and conditions can affect the color of butter. Although there are not enough studies color of butter in the literature, this study examined whether a relationship between some other properties of butter and color. Thus, the usability of color as a measure for different parameters of butter was questioned.
Material and method
Thirty butter samples were collected from town regions of Trabzon province, Turkey. Samples were immediately transported in the cold chain to the laboratory at Food Engineering Department at Ataturk University. Butter samples were stored in sterile closed plastic containers at 4°C until further analysis. Some sample was taken from each butter sample and stored at -20oC until analysis to determine butter fatty acid composition.
Dry matter, fat and salt contents, melting point, peroxide value, iodine value, saponification value, Reichert-Meissl number and polenske value were determined according to the methods of Kurt et al. . pH values of the samples were measured using a digital pH meter (pH 211, Hanna Instruments, Italy) according to the method of Kosikowski . Titratable acidity (lactic acid %) was determined according to the method of Metin . The butter samples’ water activity (aw) was measured using LabMaster-aw (Novasina AG, Switzerland).
Colour measurement of the butter samples was performed using a Minolta Colorimeter using the Hunter scale according to the method of Elgün et al. .
Fatty acid methyl esters (FAME) were prepared as described by Erkaya et al.  and Metcalfe and Schmitz . 50 mg of each butter sample was weighed and placed into glass tubes. 1,5 mL of NaOH (2M) solution was added and the tubes were filled with nitrogen gas. The Tubes were heated at 80oC for one h. 2 mL of BF3 (%25, in methanol w/v) solution was added to the tubes after cooling and heated again at 80oC for 30 min. 1 mL of hexane and 1 mL ultra distilled water was added to the tubes and vortexed. Upper layers were transferred to GC vials. These esters were injected into a GC system (Agilent 6890N, HP, USA) equipped with a flame ionization detector (Agilent Tech. Inc.) at 200oC and DB-23 column (60 m x 0.25 mm x 0.25 mm).
Helium was used as the carrier gas and C19:0 was used as the internal standard.
Correlation analyses were performed with SPSS statistical software program version 17.0 (SPSS Inc., Chicago, IL, USA).
The statistical relationship between some properties of butter and color values is given in Table 1. Pearson correlation coefficients between color values (L*, a*,b*) and different properties of butter revealed some statistically significant correlations.
Statistically significant correlations were found between the color of butter and dry matter (L* P<0.01, a* P<0.05), fat (L* P<0.05, a* P<0.05) and salt ratio (L* P<0.01, a* P<0.01), peroxide value (L* P<0.05), melting point (L* P<0.01, a* P<0.01) and polenske number (L* P<0.05, b* P<0.05).
The statistical relationship between fatty acids of butter and color values is given in Table 2. Statistically significant relationships were found between C6:0 (P<0,01), C8:0 (P<0,05) and C10:0 (P<0,05) fatty acids and L* value in accordance with the statistical relationship between the Polenske number and L* value.
On the other hand, C18:0, C18:1 and C18:2 fatty acids were also statistically significant with L* and a* values. As a matter of fact, Gonzalez et al.  stated that the butter sample having a high C18:1 value had a higher L* value than the control butter sample.
O’Callaghan et al.  mentioned that no significant difference was observed in the butter’s L* and a* values at different cow feeding systems and different trans-β-carotene content; however, significant differences were recorded for the b* value of the butter. In this study, we found significant relationships between fatty acids and L* and a* values.
In this study, as expected, dry matter, the fat, salt content of butter and peroxide number were found to be statistically related to color values. Interestingly, the number of polenske and fatty acids was also significantly correlated with the color values of butter. These results show that fatty acids can affect the color of butter. However, further research is needed.
 S. Göktürük, E. Sezgin, Z. Yildirim and M. Atamer, “Effects of season on vitamins A and E contents and colour of Turkish butter”, Nahrung-Food, 46, pp. 54-55, 2002.
 S. Prache, A. Priolo, H. Tournadre, R. Jailler, H. Dubroeucq, D. Micol, B. Martin, J. Durand, J. Emile, and C. Huyghe, “Traceability of grass-feeding by quantifying the signature of carotenoid pigments in herbivores meat, milk and cheese.” . Proc. 19th General Meeting of the Eur. Grassl. Fed., La Rochelle, Multi-Function Grasslands: Quality Forages, Animal Products, and Landscapes, pp. 592–593, 2002.
 T. F. O’Callaghan, H. Faulkner, S. McAuliffe, M. G. O’Sullivan, D. Hennessy, P. Dillon, K. N. Kilcawley, C. Stanton, and R. P. Ross. “Quality characteristics, chemical composition, and sensory properties of butter from cows on pasture versus indoor feeding systems.” J. Dairy Sci, vol. 99, pp. 9441–9460, 2016.
 E. Frede. “Butter and other milk products, properties and analysis.” Encyclopedia of Dairy Sciences, 2nd ed, pp. 506–51, 2011.
 A. J. Krause, R. E. Miracle, T. H. Sanders, L. L. Dean, and M. A. Drake. “The effect of refrigerated and frozen storage on butter flavor and texture.” J. Dairy Sci. 91, pp. 455–465, 2008.
 O. Samet-Bali, M.A. Ayadi, and H. Attia. “Traditional Tunisian butter: physicochemical and microbial characteristics and storage stability of the oil fraction.” Food Sci. and Tech., vol. 42, p.p. 899-905, 2009.
 A. Kaya. “Properties and stability of butter oil from milk and yogurt.” Narung, vol. 44, pp. 126–129, 2000.
 F.J. Méndez-Cid, J.A. Centeno, S. Martínez and J. Carballo. “Changes in the chemical and physical characteristics of cow’s milk butter during storage: Effects of temperature and addition of salt.” J. Food Compos. Anal., vol. 63, pp. 121–132, 2017.
 M. Kashaninejad, S.M.A. Razavi, M.M. Tehrani, and M. Kashaninejad. “Effect of extrusion conditions and storage temperature on texture, color, and acidity of butter.” Int J Dairy Technol, vol. 70(1), p.p. 102-109, 2017.
 A. Kurt, S. Çakmakçı and A. Çağlar. Süt ve Mamülleri Muayene ve Analiz Metodları Rehberi. Atatürk Üniversitesi Ziraat Yayınları No: 18, p.p. 106-124, 1993.
 F.V. Kosikowski. Cheese and Fermented Milk Foods. Published by F.V. Kosikowski and Associates, New York, 1982.
 M. Metin. Süt ve Mamulleri Analiz Yöntemleri. EÜ, Ege Meslek Yüksekokulu Yay. No: 24, İzmir. 2009.
 A. Elgün, Z. Ertugay, M. Certel and H. G. Kotancilar. Guide book for analytical quality control and laboratory for cereal and cereal products. 2002.
 T. Erkaya, B. Urkek, U. Doğru, B. Çetin and M. Şengül. “Probiotic butter: stability, free fatty acid composition, and some quality parameters during refrigerated storage.” Int Dairy J, vol. 49, p.p. 102–110, 2015.
 L.D. Metcalfe and A. Schmitz. “The rapid preparation of fatty acid esters for gas chromatographic analysis.” Anal. Chem., vol. 33, p.p. 363-364, 1961.
 S. Gonzalez, S.E. Duncan, S.F. O’Keefe, S.S. Sumner, and J.H. Herbein. “Oxidation and Textural Characteristics of Butter and Ice Cream with Modified Fatty Acid Profiles.” J.Dairy Sci., vol. 86, p.p. 70–77, 2003.
You can cite this study as; Akgul, HI and Sengul, M 2019. “Relationship between some parameters and color in butter.” 3rd International Conference on Advanced Engineering Technologies (ICADET 2019). Proceedings book p.p. 1770 – 1773. (see the conference website and see the proceedings book)