Determination of the low molecular weight fraction of food-grade carrageenans

• Published in: Journal of chromatography. B, Analytical technologies in the biomedical and life sciences Vol. 861; no. 1; pp. 81 - 87
• Main Authors: Spichtig, Véronique, Austin, Sean
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 2008; Elsevier Science
• Subjects: Analysis; Analytical, structural and metabolic biochemistry; Biological and medical sciences; Carrageenan - analysis; Carrageenan - chemistry; Carrageenan - standards; Chromatography, Gel - methods; Food; Food Analysis - methods; Fundamental and applied biological sciences. Psychology; General pharmacology; HPSEC; Hydrogen-Ion Concentration; Low molecular weight carrageenan; Medical sciences; Molecular Weight; Pharmacology. Drug treatments; Poligeenan; Reference Standards; Reproducibility of Results; ι-Carrageenan; κ-Carrageenan; κ-Carrageenan; Low molecular weight carrageenan; ι-Carrageenan; HPSEC; Poligeenan; Food; Low molecular weight compound; Carrageenan; Determination; Polysaccharide; Low molecular weight; Quantitative analysis; Gel permeation chromatography
• ISSN: 1570-0232; 1873-376X
• DOI: 10.1016/j.jchromb.2007.11.012

Recently there has been some debate regarding the presence and associated health risk of low molecular weight carrageenan in foodstuffs. Unfortunately measurement of the low molecular weight tail (LMT) of food-grade carrageenans (defined here as the carrageenan having relative molecular mass (Mr) below 50,000) is not trivial, largely due to its low abundance. So far methods employing light scattering have been unsuccessful in producing reproducible results, probably due to the poor detector response at low masses. In this work a method based on high performance size exclusion chromatography coupled to a refractive index detector (HPSEC-RI) has been used for the measurement of the LMT in food-grade carrageenan ingredients and in a carrageenan-containing finished product (a jelly). Over the course of half a year, 19 measurements were made on a reference carrageenan; the results demonstrated that the method had excellent reproducibility. Applied to a number of different carrageenan ingredients, it was found that, in general, the LMT represents less than 8% of the total carrageenan in ingredients, and under the correct conditions increases little during food processing. The data also indicated that pH appears to be a critical factor during food processing and pH levels below 4.0 should be avoided.