HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Purna, S. K. G. Articles by Metzger, L. E. Search for Related Content PubMed PubMed Citation Articles by Purna, S. K. G. Articles by Metzger, L. E.

Utilization of Front-Face Fluorescence Spectroscopy for Analysis of Process Cheese Functionality

MN-SD Dairy Foods Research Center, Department of Food Science and Nutrition, University of Minnesota, St. Paul 55108

Corresponding author: Lloyd E. Metzger; e-mail: lmetzger{at}umn.edu.

The purpose of this study was to evaluate the feasibility of front-face fluorescence spectroscopy (FFFS) to predict the meltability of process cheese spreads or products. Twenty-seven commercial samples from 3 manufacturers were used in this study. Each sample was analyzed using dynamic stress rheometry, which was used to calculate the meltability index (temperature at tan = 1). Additionally, fluorescence spectra of tryptophan (excitation: 290 nm; emission: 305 to 400 nm) were collected on each sample at 20°C using a front-face accessory. Fluorescence spectrum for each sample consisted of an average of 36 scans (6 scans performed on 6 replicates). The spectral data set consisted of normalized and mean-centered spectra from all the samples. Multivariate statistical analysis was used to correlate spectral data with cheese meltability index as measured by dynamic stress rheometry. A prediction model was developed using partial least square regression and was calibrated using a cross-validation method. A correlation coefficient of 0.93 was obtained between fluorescence spectra and cheese meltability. The regions 335 to 350 nm and 385 to 400 nm had the highest correlation to cheese meltability. A negative correlation between the peak height of tryptophan (335 to 350 nm) and cheese meltability index was observed. This correlation may be due to presence of tryptophan residues in a more hydrophobic environment in stronger emulsions as compared with a more polar environment in weak emulsions. These results indicate that the melt properties of process cheese spreads or products are related to molecular structure that can be measured using FFFS. Hence, FFFS can be used as an analysis technique to predict process cheese meltability.

Key Words: fluorescence • process cheese • multivariate statistics • meltability

Abbreviation key: DSR = dynamic stress rheometry, FFFS = front-face fluorescence spectroscopy, PLS = partial least square regression, PRESS = prediction residual error sum square.

This article has been cited by other articles:

				R. R. Gangidi and L. E. Metzger Ionic calcium determination in skim milk with molecular probes and front-face fluorescence spectroscopy: simple linear regression. J Dairy Sci, November 1, 2006; 89(11): 4105 - 4113. [Abstract] [Full Text] [PDF]