Quality of Brazilian vegetable oils evaluated by (modulated) differential scanning calorimetry
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Vegetable oils are increasingly replacing fossil-oil-based polymers, and therefore aimed at being used in polymerization reactions from −20 to 100 °C. Therefore, phase transitions and heat capacities in this temperature range should be well characterized to optimize processing conditions and energy inputs. By using the DSC analysis, only small primary correspondence or divergence between different oil types are seen as a function of their degree of unsaturation, but it does not clearly distinguish detailed features such as shoulder bands related to the separate melting processes of single fatty acid components. By using modulated DSC analysis, the combined analysis of reversing and non-reversing heat signals provides better results. The latter confirms that the melting is not a physical one-step process, but equilibrates between phase transitions and enthalpic reorganizations of the fatty acids that can be monitored separately. The specific heat capacities measured during modulated DSC are somewhat lower than traditional calorimetric measurements, but relate to the degree of unsaturation. The thermal behavior of palm-, soy-, sunflower-, corn-, castor-, and rapeseed-oil is discussed in relation to their composition, by applying a first or second heating scan.
KeywordsThermal analysis Heat Flow Heat capacity Modulated DSC Vegetable oil
P. Samyn acknowledges the Robert Bosch Foundation for support in the Junior professorship program. H. Van den Abbeele and G. Schoukens thank the Institute for the Promotion of Innovation by Science and Technology in Flanders (I.W.T.) for a funding program ‘SNAP’ (contract grant IWT-080213).
- 7.Correia IMS, Souza MJB, Araújo AS, Sousa EMBD. Thermal stability during pyrolysis of sunflower oil produced in the northeast of Brazil. J Therm Anal Calorim. 2011. doi: 10.1007/s10973-011-1773-5.
- 8.Tavares MLA, Queiroz N, Santos IMG, Souza AL, Cavalcanti EHS. The use of DSC in evaluation of antioxidant efficiency. J Therm Anal Calorim. 2011. doi: 10.1007/s10973-011-1357-4.
- 19.Salimon J, Abdullah BM. A study on the thermal properties and solid fat content of Malaysian rubber seed oil. Malays J Anal Sci. 2009;13:1–7.Google Scholar
- 23.Kawamura K. The DSC thermal analysis of crystallization behaviour in high erucic acid rapeseed oil. JAOCS. 1981;8:826–9.Google Scholar
- 25.Tan CP, Che Man YB. Quantitative differential scanning calorimetric analysis for determining total polar compounds in heated oils. JAOCS. 1999;9:1047–57.Google Scholar
- 29.Nzikou JM, Matos L, Moussounga JE, Ndangiu CB, Pambou-Tobi NP, Bandzouzi EM, Kimbonguila A, Linder M, Desobry S. Study of oxidative and thermal stability of vegetable oils during frying. Res J Appl Sci. 2009;4:94–100.Google Scholar
- 30.Azis A, Mohamud Y, Roselina K, Boo HC, Nyuk L, Che Man YB. Rheological, chemical and DSC thermal characteristics of different types of palm oil/palm stearing-based shortenings. Int Food Res J. 2011;18:189–200.Google Scholar
- 31.Abdulkarim SM, Ghazali HM. Comparison of melting behaviours of edible oils using conventional and hyper differential scanning calorimetric scan rates. ASEAN Food J. 2007;14:25–35.Google Scholar
- 34.Samyn P, Van Nieuwkerke D, Schoukens G, Vonck L, Stanssens D, Van den Abbeele H. Quality and statistical quantification of Brazilian vegetable oils using FTIR and Raman spectroscopy. Appl Spectrosc. 2011.Google Scholar
- 35.Carneiro PIB, Reda SY, Carneiro EBB. H-NMR characterization of seed oils from Rangpur lime and Sicilian lemon. Ann Magn Reson. 2005;4:64–8.Google Scholar
- 38.Deman JM, Deman L, Blackman B. Melting-point determination of fat products. JAOCS. 1983;60:15–8.Google Scholar
- 40.Jacobsberg B, Ho OC. Studies in palm oil crystallization. JAOCS. 1976;71:609–17.Google Scholar
- 47.Siew WL, Ong ASH, Oh FCH, Berger KG. Critical aspects of slip melting point measurements. PORIM Bull. 1982;4:1–18.Google Scholar
- 49.Choi Y, Okos MR. Food engineering and process applications, vol 1. In: Jelen P, Le Maguer M, editors. Transport phenomena. London: Elsevier Applied Science; 1986. p. 93–101.Google Scholar