The effect of composition on butter texture usually has been treated via the iodine value or the fatty acid content. The development of a new analytical technique allowed accurate determination of triglyceride composition of five different types of butters collected in winter and summer periods. The firmness of these samples has been measured in parallel, by using an Instron(R) universal testing machine and a cone penetrometer. As expected, a regional and seasonal variation of butter firmness was found. The correlation between firmness at 15-degrees-C and triglyceride composition allows the selection of four triglyceride fractions (TG1, TG2, TG3 and TG4) mainly represented by: TG1, POO; TG2, MyOO; TG3, CLaO + CyMyO + CoPO + BuSO and TG4, BuPO + CoMyO + CoPL (P, palmitic acid; O, oleic acid; My, myristic acid; C, capric acid; La, lauric acid; Cy, caprylic acid; Co, caproic acid; Bu, butryic acid; S, stearic acid; L, linoleic acid). The proportions of TG1 and TG2 are negatively correlated with firmness (r = 0.89 and r = 0.95, respectively). The level of the two other groups runs parallel to firmness (r = 0.95 and r = 0.91, respectively). The high correlation coefficients of these prevalent triglyceride fractions could be a better representative indication than iodine value or fatty acid content on the variation of this physical property of butter.
