Overview
ISO 23275-1:2006 specifies a laboratory procedure to detect the presence of cocoa butter equivalents (CBEs) in cocoa butter and plain chocolate. The method uses high-resolution capillary gas–liquid chromatography (HR‑GC) of triacylglycerols (TAGs) combined with regression data evaluation. It is validated to detect 2% CBE in cocoa butter, which corresponds to about 0.6% CBE in chocolate (assuming 30% fat content). The standard is Part 1 of ISO 23275 (Part 2 covers quantification).
Key Topics and Requirements
- Analytical principle: Separation of TAG fractions by HR‑GC and detection by flame ionization detector (FID); identification based on comparison with a certified cocoa butter reference material (CRM).
- Target triacylglycerols: POP, POS, POO, SOS and SOO are the primary TG fractions used for identification and regression analysis.
- Calibration and CRM: Use of the cocoa butter CRM (IRMM‑801) for calibration and system‑suitability checks is mandated.
- Performance and sensitivity: Method applicable to detect 2% CBE in cocoa butter (~0.6% in chocolate).
- Chromatographic conditions (recommended):
- Capillary column: 25–30 m × 0.25 mm i.d., thermostable 50% phenylmethylpolysiloxane, film 0.10–0.15 µm
- Temperature program: 100 °C initial, ramp 30 °C/min to 340 °C
- Carrier gas: helium or hydrogen (≥ 99.999%)
- Data evaluation: Response factors determined from the CRM; percentage TAGs calculated and assessed by regression (example decision line given: POP = 43.734 − 0.733 × SOS; residual standard deviation = 0.125).
- Sample preparation: Fat extraction from grated chocolate using non‑chlorinated solvents; dilution and injection protocols for HR‑GC.
- Quality controls: System suitability checks, instrument linearity, and reporting to two decimal places.
Applications and Who Uses It
- Food testing laboratories validating raw materials and finished products for authenticity.
- Chocolate and confectionery manufacturers performing incoming raw material QC and product verification.
- Regulatory authorities and customs enforcing labeling and composition rules (e.g., compliance with Directive 2000/36/EC).
- Research and reference laboratories developing or validating analytical methods for fats and oils authenticity.
Practical uses include screening for adulteration with vegetable fats (shea, illipé, sal, palm, mango kernel, kokum) that are used as CBEs.
Related Standards
- ISO 23275-2 - Quantification of cocoa butter equivalents (provides reliable quantification at the 5% level).
- ISO 5555 - Recommended sampling methods for chocolate (sampling is outside the scope of ISO 23275-1 but referenced).
- CoCal‑1 toolbox - validated methods, CRM (IRMM‑801) and evaluation spreadsheet referenced to facilitate detection and quantification workflows.
Keywords: ISO 23275-1:2006, cocoa butter equivalents, CBEs, HR‑GC, triacylglycerols, cocoa butter, plain chocolate, IRMM-801, food testing, gas chromatography.