Identification of Imitation Cheese and Imitation Ice Cream Based on Vegetable Fat Using NMR Spectroscopy and Chemometrics.

Yulia B Monakhova,Dirk W Lachenmeier,Claudia Andlauer,Rolf Godelmann,Thomas Kuballa

doi:10.1155/2013/367841

Abstract

Vegetable oils and fats may be used as cheap substitutes for milk fat to manufacture imitation cheese or imitation ice cream. In this study, 400 MHz nuclear magnetic resonance (NMR) spectroscopy of the fat fraction of the products was used in the context of food surveillance to validate the labeling of milk-based products. For sample preparation, the fat was extracted using an automated Weibull-Stoldt methodology. Using principal component analysis (PCA), imitation products can be easily detected. In both cheese and ice cream, a differentiation according to the type of raw material (milk fat and vegetable fat) was possible. The loadings plot shows that imitation products were distinguishable by differences in their fatty acid ratios. Furthermore, a differentiation of several types of cheese (Edamer, Gouda, Emmentaler, and Feta) was possible. Quantitative data regarding the composition of the investigated products can also be predicted from the same spectra using partial least squares (PLS) regression. The models obtained for 13 compounds in cheese (R 2 0.75–0.95) and 17 compounds in ice cream (R 2 0.83–0.99) (e.g., fatty acids and esters) were suitable for a screening analysis. NMR spectroscopy was judged as suitable for the routine analysis of dairy products based on milk or on vegetable fat substitutes.

Highlights

Due to industry efforts to provide low-cost foods or due to general ethical considerations against cow’s milk consumption [1], imitation dairy products have recently appeared on the market [2,3,4,5]
The nuclear magnetic resonance (NMR) spectra obtained with both methods showed the same fatty acid profile; the automated device was considerably more efficient as it is possible to prepare 6 samples at once without human intervention
Results (i.e., root mean square error (RMSE), correlation coefficient (R2), the number of partial least squares (PLS) factors as well as NMR range used) of the best-fitting PLS models for ice creams were listed in Traditional analytical strategies to uncover adulteration of food rely on targeted analysis

Summary

Introduction

Due to industry efforts to provide low-cost foods or due to general ethical considerations against cow’s milk consumption [1], imitation dairy products have recently appeared on the market [2,3,4,5]. While not being harmful to health, the imitation products may be of lesser nutritional quality (e.g., by lower calcium content) and contain several artificial flavors and food colors [10]. Such imitation products may be offered without the necessary labeling, which is a deception of the consumer. It has become necessary to develop a reliable technique able to detect such products in the market

Objectives

Results

Conclusion