Comparing the use of chloroform to petroleum ether for Soxhlet extraction of fat in meat
Peter Watkins
A *
A CSIRO Agriculture and Food, 671 Sneydes Road, Werribee, Vic. 3030, Australia.
Animal Production Science 63(14) 1445-1449 https://doi.org/10.1071/AN23014
Submitted: 30 January 2023 Accepted: 19 June 2023 Published: 10 July 2023
© 2023 The Author(s) (or their employer(s)). Published by CSIRO Publishing. This is an open access article distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND)
Abstract
Context: Soxhlet extraction is commonly used for determining fat content of meat, because it is the basis of the AOAC Final Action method for this analysis. Petroleum ether is used as an extraction solvent but other solvents, such as chloroform, can be used. Chloroform has been stated to be a safer solvent than petroleum ether and is used extensively for Soxhlet extraction for meat research in Australia; yet, there has been no report that validates its use for this purpose.
Aim: To compare the use of chloroform with that of petroleum ether as an extraction solvent for Soxhlet fat extraction in beef.
Methods: The fat content of six beef samples, reported as chemical lean (CL, 100 – %fat), was determined using Soxhlet fat extraction with chloroform (by two independent research providers) and petroleum ether (b.p. 40–60°C, using three commercial providers). Passing–Bablok regression and Bland–Altman plot analysis were used to identify any differences and bias between the methods respectively.
Key results: Passing–Bablok regression showed that there was no difference between the use of chloroform and the use of petroleum ether as a solvent for Soxhlet fat extraction in beef. Bland–Altman plot analysis indicated that there was no bias evident between the uses of each solvent. Thus, this would indicate that chloroform can be used as a solvent for Soxhlet fat extraction, providing equivalency to petroleum ether. While some minor differences were apparent, this is most likely attributable to sample heterogeneity.
Conclusions: Chloroform was found to provide equivalency to petroleum ether for fat extraction from meat. While some minor differences were apparent in the fat content of meat, this has been attributed to likely sample heterogeneity.
Implications: Chloroform can be used as an extraction solvent for Soxhlet fat extraction of beef.
Keywords: Bland–Altman, chemical lean, fat content, fat determination, meat quality, method comparison, Passing–Bablok, Soxhlet extraction.
References
Anonymous (1998) Meat technology information sheet – crude fat determination – Soxhlet method. Available at https://meatupdate.csiro.au/infosheets/Crude%20Fat%20Determination%20-%20Soxhlet%20Method%20-%201998.pdfAnonymous (2000) ‘AOAC Official Method 960.39, Fat (crude) or ether extract in meat, final action.’ 17th edn. (Official Methods of Analysis of AOAC International: Gaithersburg, MD, USA)
Bilić-Zulle L (2011) Comparison of methods: Passing and Bablok regression. Biochemia Medica 21, 49–52.
| Comparison of methods: Passing and Bablok regression.Crossref | GoogleScholarGoogle Scholar |
Carstensen B, Gurrin L, Ekstrøm CT, Figurski M (2020) MethComp: analysis of agreement in method comparison studies. Available at https://CRAN.R-project.org/package=MethComp
Doğan NÖ (2018) Bland-Altman analysis: a paradigm to understand correlation and agreement. Turkish Journal of Emergency Medicine 18, 139–141.
| Bland-Altman analysis: a paradigm to understand correlation and agreement.Crossref | GoogleScholarGoogle Scholar |
Fang C, Behr M, Xie F, Lu S, Doret M, Luo H, Yang W, Aldous K, Ding X, Gu J (2008) Mechanism of chloroform-induced renal toxicity: non-involvement of hepatic cytochrome P450-dependent metabolism. Toxicology and Applied Pharmacology 227, 48–55.
| Mechanism of chloroform-induced renal toxicity: non-involvement of hepatic cytochrome P450-dependent metabolism.Crossref | GoogleScholarGoogle Scholar |
Firth NL, Ross DA, Thonney ML (1985) Comparison of ether and chloroform for Soxhlet extraction of freeze-dried animal tissues. Journal of Association of Official Analytical Chemists 68, 1228–1231.
| Comparison of ether and chloroform for Soxhlet extraction of freeze-dried animal tissues.Crossref | GoogleScholarGoogle Scholar |
Gemperline P (Ed.) (2006) ‘Practical guide to chemometrics.’ (CRC Press) https://doi.org/10.1201/9781420018301
Giavarina D (2015) Understanding Bland Altman analysis. Biochemia Medica 25, 141–151.
| Understanding Bland Altman analysis.Crossref | GoogleScholarGoogle Scholar |
Kalra A (2017) Decoding the Bland–Altman plot: basic review. Journal of the Practice of Cardiovascular Sciences 3, 36–38.
| Decoding the Bland–Altman plot: basic review.Crossref | GoogleScholarGoogle Scholar |
Kopp-Schneider A, Hielscher T (2019) How to evaluate agreement between quantitative measurements. Radiotherapy and Oncology 141, 321–326.
| How to evaluate agreement between quantitative measurements.Crossref | GoogleScholarGoogle Scholar |
Passing H, Bablok W (1983) A new biometrical procedure for testing the equality of measurements from two different analytical methods. Application of linear regression procedures for method comparison studies in Clinical Chemistry, Part I. Clinical Chemistry and Laboratory Medicine 21, 709–720.
| A new biometrical procedure for testing the equality of measurements from two different analytical methods. Application of linear regression procedures for method comparison studies in Clinical Chemistry, Part I.Crossref | GoogleScholarGoogle Scholar |
Perry D, Shorthose WR, Ferguson DM, Thompson JM (2001) Methods used in the CRC program for the determination of carcass yield and beef quality. Australian Journal of Experimental Agriculture 41, 953–957.
| Methods used in the CRC program for the determination of carcass yield and beef quality.Crossref | GoogleScholarGoogle Scholar |
R Core Team (2022) ‘R: a language and environment for statistical computing.’ (R Foundation for Statistical Computing: Vienna, Austria)
Stewart S, Watkins P, Pethick DW, McGilchrist P, Stockham K, Gardner GE (2020) Repeatability of a chloroform Soxhlet extraction method used to determine chemical fat content in beef. Department of Agriculture, Water and the Environment, Program E4: 7.1.10, Canberra, ACT, Australia.
Stewart SM, Lauridsen T, Toft H, Pethick DW, Gardner GE, McGilchrist P, Christensen M (2021) Objective grading of eye muscle area, intramuscular fat and marbling in Australian beef and lamb. Meat Science 181, 108358
| Objective grading of eye muscle area, intramuscular fat and marbling in Australian beef and lamb.Crossref | GoogleScholarGoogle Scholar |
Vander Heyden Y, Smeyers-Verbeke J (2007) Set-up and evaluation of interlaboratory studies. Journal of Chromatography A 1158, 158–167.
| Set-up and evaluation of interlaboratory studies.Crossref | GoogleScholarGoogle Scholar |
Watkins P, Stockham K, Stewart S, Gardner G (2021) Contemporary chemical lean determination used in the Australian meat processing industry: a method comparison. Meat Science 171, 108289
| Contemporary chemical lean determination used in the Australian meat processing industry: a method comparison.Crossref | GoogleScholarGoogle Scholar |
