Obi Junji, Yoshinaga Kazuaki, Tago Arisa, Nagai Toshiharu, Yoshida Akihiko, Beppu Fumiaki, Gotoh Naohiro
Department of Food Science and Technology, Tokyo University of Marine Science and Technology.
Tsukishima Foods Industry Co. Ltd.
J Oleo Sci. 2018 Aug 1;67(8):941-948. doi: 10.5650/jos.ess18039. Epub 2018 Jul 17.
The analysis of lactones as an indicator of milk quality is important in food manufacturing. However, the extraction of lactones requires sensitive conditions due to their volatility. In this study, the parameters for resolution of lactone standards were evaluated by gas chromatography-electron ionization/mass spectrometry (GC-EI/MS) to develop a rapid and simple method for the quantification and compositional analysis of lactones in edible fats, especially milk fat. Fourteen lactone standards consisting of 6-16 carbon atoms were analyzed and their correction factors (CFs) were obtained by using δ-undecalactone as an internal standard. The CFs of the lactone standards followed the same trend for δ-lactones and γ-lactones. Three volume equivalents of organic solvent per unit sample yielded the best recovery in the lactone analysis. Notably, 91-114% lactone recovery for the standards was achieved with methanol as the extractant. This method was also applicable to other fat samples, such as virgin coconut oil that is thought to contain large amounts of lactones. The recovery of lactones from virgin coconut oil was in the range of 87-104%, indicating that the developed method is also applicable to solid or semi-solid fat samples. The lactone content of butter oil, coconut oil, and butter samples was calculated by using the obtained CFs and the results were in good agreement with those of previous reports. Consequently, the GC-EI/MS method developed in this study is deemed applicable for the quantification of lactones in fat samples.
内酯作为牛奶质量指标的分析在食品制造中很重要。然而，由于内酯具有挥发性，其提取需要敏感条件。在本研究中，通过气相色谱 - 电子电离/质谱联用仪（GC - EI/MS）评估内酯标准品的分离参数，以开发一种快速简便的方法，用于定量分析食用脂肪尤其是乳脂肪中的内酯及其成分。分析了14种含6 - 16个碳原子的内酯标准品，并以δ-十一内酯作为内标物获得其校正因子（CFs）。内酯标准品的CFs在δ-内酯和γ-内酯方面呈现相同趋势。在内酯分析中，每单位样品加入三倍体积当量的有机溶剂可获得最佳回收率。值得注意的是，以甲醇作为萃取剂时，标准品的内酯回收率达到91 - 114%。该方法也适用于其他脂肪样品，如被认为含有大量内酯的初榨椰子油。从初榨椰子油中回收内酯的范围为87 - 104%，表明所开发的方法也适用于固体或半固体脂肪样品。利用获得的CFs计算了黄油、椰子油和奶油样品中的内酯含量，结果与先前报道的结果高度一致。因此，本研究开发的GC - EI/MS方法被认为适用于脂肪样品中内酯的定量分析。
