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Trans Fat Lab to Label. What is trans fat? Chemically: Geometric isomers of the natural cis form of unsaturated fatty acids Physically: Fatty acids modified.

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Presentation on theme: "Trans Fat Lab to Label. What is trans fat? Chemically: Geometric isomers of the natural cis form of unsaturated fatty acids Physically: Fatty acids modified."— Presentation transcript:

1 Trans Fat Lab to Label

2 What is trans fat? Chemically: Geometric isomers of the natural cis form of unsaturated fatty acids Physically: Fatty acids modified to have a higher melting point by changing their configuration from bent to straight.

3 What is a Trans Fat? Oleic (9-cis-C18:1) mp: 13-14C Elaidic (9-trans-C18:1) mp: 44-45C

4 Where Does Trans Fat Come From? Chemical Hydrogenation of Vegetable Oils (may be >50%) Biochemical Hydrogenation by Rumen Bacteria (5% or less)

5 Some Food Labeling History Nutrition Labeling & Education Act 1990 Major Change in Fat Definition New Fat Methodologies Required Only cis fats included in unsaturates Call for Trans Fat Labeling Decision Delayed Pending Better Data

6 Trans Added to Label Amended to Include Trans Required by Jan 2006

7 Why Trans Fat? Trans Fat Raises LDL Cholesterol/Lowers HDL Trans Fat Increases Plasma TGs May Be Stronger CHD Factor than Saturated Fat Up to 100,000 Premature Deaths/yr in US Average US Consumer Gets 2% of Calories from Trans Fat

8 What Foods Contain Trans Fat? Margarines (Hard varieties are higher) Shortenings and Frying Fats Fried Foods Beef and Dairy Fats Bakery Products But.... Changing Rapidly

9 How Are They Measured? Usually complex mixtures PHVO can have >40 isomers of 18 Carbon FA More than 15 isomers of linoleic acids

10 Hydrogenation Increases Complexity Salad Oil – no hydrogenation C18:0 C18:1C18:2

11 Hydrogenation Increases Complexity Margarine C18 region only C18:1C18:2 Trans C18:1

12 How Are They Measured? FTIR for Process Control of Fats and Oils (high levels, not for complex foods, specific) HRGC for Products and Ingredients (low levels, complex foods, not specific) Ag+ Chromatography/GC (Not practical at present, but may be useful in future)

13 Accurate Measurement of Trans Fat in Foods Specialized GC Capillary Columns Very Long Columns (100 meters) Optimized Separation of Trans Fats

14 Overview of Method for Measuring Fat Crude Extract Saponify with KOH Esterify with Acid/MeOH Separate and Measure by GC Critical step for trans fat

15 Optimized Trans Analysis Standard Separation (Could underestimate Trans by up to 25%) Optimized Separation

16 Optimized Trans Fat Separation 100 Meter Capillary Column Specialized Stationary Phases Isothermal Column Temperature Split Injection

17 US and Canadian Food Labels US Canada List Separately List Sum

18 Trans Fat Label Requirements US Label trans fat >0.5 g per serving If total fat < 0.5 g per serving, not required, but Not a significant source of trans fat No fat or cholesterol claims allowed No nutrient content claims for trans fat Canada Both sat fat and trans fat <0.2 g per serving to list as zero Limited use of Not a significant source

19 Future Other Label Changes Being Studied May Add a %DV for Trans Fat May Allow Nutrient Content Claims for Trans Fat Trans Fats Rapidly Disappearing from Food Products

20 Online Resources Harvard School of Public Health Trans Fat Report: FDA Trans Fat Labeling Q&A Sites


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