DEVELOPMENT AND CHARACTERIZATION OF LAURIC ACID OLEOGELS

Öz

In this study, sunflower oil oleogels were developed with lauric acid, Span 60, and Pluronic F68 (10% poloxamer 188). Physicochemical, thermal, structural, and rheological properties of the oleogels were determined. The gel formation time of oleogels containing only LA (20%) was shorter than oleogels containing 15% LA and 5% emulsifiers, and an increase in LA concentration shortened the gel formation time. While there were differences in the color values of the oleogels depending on the LA concentration and emulsifier type, the oil binding capacity of all oleogel samples were quite high. The crystalline structures were observed under polarized light microscope, and the X-ray diffraction patterns proved the existence of β and β՛ polymorph crystals. Rheological analyses indicated that oleogels had good structural recovery ability. Further, addition of emulsifier allowed oleogel formation with lower concentrations of LA, and at the same time the gel stability was enhanced with emulsifier.

Anahtar Kelimeler

• lauric acid
• emulsifier
• oleogel
• rheology
• microstructure
• stability

LAURİK ASİT OLEOJELLERİNİN GELİŞTİRİLMESİ VE KARAKTERİZE EDİLMESİ

Öz

Bu çalışmada laurik asit (LA) oleojelatörü Span 60 ve Pluronic F68 (%10 poloksamer 188) emülgatörleriyle birlikte kullanılarak ayçiçek yağı oleojelleri geliştirilmiştir. Geliştirilen oleojellerin fizikokimyasal, termal, yapısal ve reolojik özellikleri belirlenmiştir. Sadece LA içeren (%20) oleojellerin jel oluşum zamanının %15 LA ve %5 emülgatör içeren oleojellerden daha kısa olduğu, LA konsantrasyonundaki artışın jel yapı oluşum zamanını kısalttığı gözlenmiştir. LA konsantrasyonu ve emülgatör çeşidine bağlı olarak oleojellerin renk değerlerinde farklılıklar görülürken tüm oleojel örneklerinin yağ bağlama kapasitelerinin yüksek olduğu belirlenmiştir. Polarize ışık mikroskobu görüntülerinde oleojellerin ince kristal yapılar oluşturduğu gözlenirken, X-ışını kırınım deseni β ve β՛ polimorf kristallerinin varlığını kanıtlamıştır. Reolojik analizlerle geliştirilen oleojellerinin yapısal geri dönüşüm yeteneğinin olduğu belirlenmiştir. Emülgatör ilavesinin daha düşük konsantrasyonlarda LA ile oleojel oluşumuna olanak sunduğu, aynı zamanda daha dayanıklı jel yapı oluşturabildiği reolojik testlerle tespit edilmiştir.

Anahtar Kelimeler

• laurik asit
• emülgatör
• oleojel
• reoloji
• mikroyapı
• stabilite

Kaynakça

1. AOCS. (2012). AOCS Official Method Cj 2-95. X-ray diffraction analysis of fats. Official Methods and Recommended Practices of the AOCS, 6th Ed. 2011-2012 Methods and Additions and Revisions.
2. Co, E.D., Marangoni, A.G. (2012). Organogels: An alternative edible oil-structing method. Journal of the American Oil Chemists’ Society, 89: 749-780. doi 10.1007/s11746-012-2049-3.
3. Davidovich-Pinhas, M. (2016). Oleogels: a promising tool for delivery of hydrophobic bioactive molecules. Therapeutic Delivery, 7 (1), 1–3. https://doi.org/10.4155/tde.15.83.
4. Eisa, A.H., Laufer, S., Rosen-Kligvasser, J., Davidovich-Pinhas, M. (2020). Stabilization of ethyl-cellulose oleogel network using lauric acid. European Journal of Lipid Science and Technology, 122 (1900044): 2-10. https://doi.org/10.1002/ejlt.201900044.
5. Harris, L., Rosen-Kligvasser, J., Davidovich-Pinhas, M. (2019). Gelation of oil using combination of different free fatty acids. Food Structure, 21: 100121-100131. https://doi.org/10.1016/j.foostr.2019.100121.
6. Hwang, H-S. (2020). A critical review on structures, health effects, oxidative stability, and sensory properties of oleogels. Biocatalysis and Agricultural Biotechnology, 26: 101657. https://doi.org/10.1016/j.bcab.2020.101657.
7. Keskin Uslu, E., Yılmaz, E. (2019). Protein emülsiyon ağıyla yapılandırılmış oleojeller. Akademik Gıda, 17(3), 410-416. https://doi.org/10.24323/akademik-gida.647730.
8. Keskin Uslu, E., Yılmaz, E. (2021). Production and characterization of oleogels with tallow and partially hydrolyzed tallow as organogelators. Grasas Y Aceties, 72 (1): 388-398. https://doi.org/10.3989/gya.1031192.

9. Mattice K.D., Marangoni A.G. (2018). Insights into wax crystal networks in oleogels. In: Edible Oil Structuring Concepts, Methods and Applications. Patel, A.R. (chief ed.), Volume1, Royal Society Chemistry, Chambridge, pp. 71-95.
10. Mezger, T.G. (2014). Applied Rheology. Volume1, Anton Paar GmbH, Austria, 191p. ISBN:10-3950401601.
11. Minitab. (2010). Minitab Statistical Software (Version 16.1). Minitab, Inc., State College, Pennsylvania, US.
12. O'Brien, R.D. (2004). Fats and Oils: Formulating and Processing For Applications. 2nd Edition, CRC press LLC, Boca Raton, Florida, 574 p. ISBN: 0-8493-1599-9.
13. Sagiri, S.S., Samateh, M., John, G. (2018). Biobased molecular structuring agents. In: Edible Oil Structuring: Concept, Methods and Applications, Patel, A.R. (chief ed.), Volume1, Royal Society Chemistry, Chambridge, pp. 25-52.
14. Singh, A., Auzanneau, F.I., Rogers, M.A. (2017). Advances in edible oleogel technologies – A decade in review. Food Research International, 97: 307–317. https://doi.org/10.1016/j.foodres.2017.04.022.
15. Uvanesh, K., Sagiri, S.S., Senthilguru, K., Pramanik, K., Banerjee, I., Arfat S., Al-Zahrani, M., Pal, K. (2016). Effect of Span 60 on the microstructure, crystallization kinetics, and mechanical properties of stearic acid oleogels: an in-depth analysis. Journal of Food Science, 81(2), E380-E387. https://doi.org/10.1111/1750-3841.13170.