Yogurt multi-way fluorescence data
Front-face fluorescence spectroscopy was applied for monitoring light induced changes in yogurt during storage.
Data from fluorescence measurements and riboflavin content, determined by traditional method is available
Christensen, J., Miquel Becker, E., and Frederiksen, C.S.
Fluorescence Spectroscopy and PARAFAC in analysis of yoghurt
Chemometrics and Intelligent Laboratory 75(2005)201-208.
Description of Data
Plain yogurt was filled into cups of two rigid packaging materials, polylactate (PLA) and polystyrene (PS), with PS having the higher oxygen permeability and light transmission. Two batches of yogurt were examined in two identical storage experiments. Analyses were performed after 0, 7, 14, 21, 28 and 35 days of storage, giving a total of 21 different samples (5 days x 2 light conditions x 2 packaging materials + one starting sample) for each batch. Thus, 42 independent samples were studied in all. Three cups from identical conditions for each of the two batches were selected and considered as triplicates. One sample from the second batch was omitted as outlier, giving a total of 125 samples (42 x 3 minus one). All analyses were carried out in duplicate. Prior to the measurements, the yogurt was mixed in the cup.
Fluorescence landscapes were recorded for excitation wavelengths 270-550 nm and emission wavelengths 310-590 nm, with intervals and bandwidths of 20 nm, giving a total of 15 excitation and 15 emission wavelengths. Only emission wavelengths 40 nm above the excitation wavelength were recorded, resulting in 120 data points. Measurents were performed directly on the yoghurt samples, using a BioView specrofluorometer with a sample probe giving an open-end 180˚ measuring geometry.
The riboflavin content in the yogurt was determined using the fluorometric method established by AOAC. This method implies a chemical extraction and cleanup of riboflavin prior to a univariat fluorometric measurement.