Analytical assessment of the intense heat load of whipping cream, coffee cream, and condensed milk at retail in Austria and Germany.

Lisa I Boitz,Helmut K Mayer

doi:10.1007/s13594-016-0295-0

Lisa I Boitz, Helmut K Mayer

Open Access

https://doi.org/10.1007/s13594-016-0295-0

Copy DOI

Abstract

Time temperature integrators (TTIs) are useful tools in estimating the heat load applied on differently processed dairy products. The objective of this study was to analyze and assess three TTIs – lactulose, furosine, and acid-soluble β-lactoglobulin (β-Lg) – in 70 high heated dairy products at retail in Austria and Germany comprising whipping cream, coffee cream/milk, and condensed milk products. While β-Lg was not appropriate to evaluate the heat load of these products, furosine and especially lactulose increased with rising intensity of heat treatment, and are appropriate to distinguish between several heating categories analyzed. Pasteurized (n = 8) and “heat treated” (n = 5) whipping cream samples showed lowest furosine (48 ± 14/ 45 ± 19 mg.100 g−1 protein) and low lactulose (29 ± 10/57 ± 28 mg.L−1) concentrations, followed by ESL whipping cream (n = 10), ESL coffee cream (n = 1), and UHT whipping cream (n = 10) (furosine = 72 ± 37/71/161 ± 30 mg.100 g−1 protein; lactulose = 56 ± 41/161/195 ± 39 mg.L−1), respectively. Sterilized condensed milk samples (n = 14) showed the highest concentrations of both TTIs and could be clearly separated from UHT treated samples (n = 5) (furosine = 491 ± 196/216 ± 46 mg.100 g−1 protein; lactulose = 1997 ± 658/409 ± 161 mg.L−1), whereas the so-called heat-treated samples (n = 9) had a heat load in between showing an extreme range of variation for both TTIs.

Highlights

Bovine liquid milk is the major dairy product consumed with 77 kg per capita and year in Austria, these commodities include whipping cream, coffee milk or coffee cream, evaporated or condensed milk as well as milk powder (AMA 2014)
Seventy retail samples including 41 whipping cream samples and 29 coffee cream/milk and condensed milk samples were analyzed for their furosine concentrations using an existing RP-HPLC method with few modifications in sample preparation because of higher fat content and higher viscosity, especially of condensed milk samples
While no dilution was necessary for proper detection of whipping cream samples (Fig. 2a, b), coffee cream/milk samples and condensed milk samples had to be diluted to avoid an overload of the HPLC column (Fig. 2c, d)

Summary

Introduction

Bovine liquid milk is the major dairy product consumed with 77 kg per capita and year in Austria, these commodities include whipping cream, coffee milk or coffee cream, evaporated or condensed milk as well as milk powder (AMA 2014). Extended Shelf Life (ESL) products have gained widespread acceptance in Austria and Germany; even “ESL” labeled coffee milk came on the market in Austria recently. The Austrian Food Codex defines “cream” as a product with at least 10% milk fat content, coffee cream contains 10–18% milk fat, whipping cream at least 30%, and a fat content of 36% is necessary for products labeled as “extra creamy” whipping cream (FMH 2011). Condensed or concentrated milk products require an additional evaporation step, commonly implemented in falling film evaporators, thereby increasing its milk solids and viscosity.

Objectives

Methods

Results

Discussion

Conclusion