Chromatography
Healthy Fat in Chips and Sausages? A new Method for Extraction, Digestion and Analysis of Fat in Food Samples by Marcel Pacheco-Moreno1
, Jürgen Schram1 , Uwe Oppermann2 , Franz Kramp2
1. University of Applied Sciences, Frankenring 20, D-47798 Krefeld, Germany 2. Shimadzu Europa GmbH, Albert-Hahn-Str. 6-10, D-47269 Duisburg, Germany 3. CEM GmbH, Carl-Friedrich-Gauß-Str. 9, D-47475 Kamp-Lintfort, Germany
A new method for the determination of saturated and unsaturated fatty acids in food samples such as chocolate, milk powder, sausages, and potato chips has been developed. The method consists of a fast and gentle microwave process in a closed system for sample preparation and the determination of fatty acids using gas chromatography with fl ame ionisation detection (GC-FID). The analytical data are compared with results of the same food samples generated on the conventional ISO procedures and advantages of the new method are explained.
Introduction
The REGULATION (EU) No 1169/ 2011 OF THE EUROPEAN PARLIAMENT requires the detailed declaration of nutrition values for food as of 2016, especially the differentiation of fat in saturated and unsaturated fatty acids [1]. This differentiation is important in order to protect consumers. For example, the American Dietetic Association (ADA), the European Food Safety Authority (EFSA) and the American ‘Academy of Nutrition and Dietetics’ recommend covering less than 35% of the body’s daily energy requirements by fat; according to ADA, less than 20% should be monounsaturated fatty acids (MUFA).
Determination of total fat content as well as unsaturated and saturated fatty acids in food is performed using methods based on ISO standards. Depending on the type of food, methods like Röse- Gottlieb or Weibull-Stoldt extraction are used for the determination of total fat content [2,3].
The following analysis of saturated and unsaturated fatty acids is done using gas chromatography (GC-FID). This analysis requires the derivatisation of fatty acids in fatty acid methyl esters (FAMEs) based on the ISO norm [4].
Figure 2. Acidic derivatisation of a fatty acid to ester with methanol under formation of water [6].
Unsaturated fatty acids are sensitive to oxidation processes generated through contact with air and infl uence of heat. That’s why a gentle microwave process has been developed which is applied in a closed system in two steps for various food compartments. This new microwave procedure is faster, cheaper and more environmentally friendly than the conventional ISO procedure.
Figure 1. Alkaline Derivatisation of a Triglyceride with methanol to ester [5].
It is assumed that the oxidation sensitive unsaturated fatty acids are treated more gently in the microwave process and oxidation is thereby minimised, resulting in a higher analytical levels result of unsaturated fatty acids.
, Frank Scholten3 , Ulf Sengutta3 ,
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96 |
Page 97 |
Page 98 |
Page 99 |
Page 100 |
Page 101 |
Page 102 |
Page 103 |
Page 104 |
Page 105 |
Page 106 |
Page 107 |
Page 108 |
Page 109 |
Page 110 |
Page 111 |
Page 112 |
Page 113 |
Page 114 |
Page 115 |
Page 116 |
Page 117 |
Page 118 |
Page 119 |
Page 120 |
Page 121 |
Page 122 |
Page 123 |
Page 124 |
Page 125 |
Page 126 |
Page 127 |
Page 128 |
Page 129 |
Page 130 |
Page 131 |
Page 132
