Sensorial Properties of Ice Tea as Affected by Packaging
Andrej Plestenjak1, Marjan Simčić1, Janez Hribar1, Marjan Veber2, Andrej Škorja3, Mira Kordiš-Krapež4, Peter Pavlič5 and Rajko Vidrih1*
1 Department of Food Science and Technology, Biotechnical faculty, University of Ljubljana, Jamnikarjeva 101, 1111 Ljubljana, Slovenia
2 Faculty of Chemistry and Chemical Technology, Aškerčeva 5, 1000 Ljubljana
3 Laško Brewery, Trubarjeva 28, 3270 Laško, Slovenia
4 BIA d.o.o. Teslova 30, 1000 Ljubljana, Slovenia
5 ETOL, Škofja vas 39, 3211 Škofja vas, Slovenia
Article history:
Received June 26, 2000
Accepted March 23, 2001
Key words:
ice tea, metal migration, ascorbic acid, HMF, sensory evaluation
Summary:
The aim of this research was to determine changes in sensorial properties of ice tea (peach and pear flavoured) filled in polyethylene terephtalate bottles (PET) and tin cans. Bottles and cans were stored at 2 °C and at 20 °C for 12 weeks. Analyses were carried out weekly on tin, iron, aluminum, 5-hydroxymethyl-2-furfuraldehyde (HMF), ascorbic acid and colour intensity. As expected, canned ice tea had higher concentration of tin, iron and aluminum as a result of migration from packaging material. Concentration of metal ions appeared not to be influenced by storage time but depended mainly on the quality of single can. Concentration of HMF, which indicates intensity of heat treatment, increased during storage. HMF and colour intensity (darker colour) were higher in canned ice tea and higher at higher storage temperature in all treatments. Retention of aroma compounds was better in pear flavoured ice tea and always higher in ice tea packed in PET bottles. The level of ascorbic acid decreased during storing with increased temperature. Faster decrease was always observed in ice tea packed in PET bottles. Sensorial properties that dictate the consumer acceptance classified ice tea packed in PET bottles superior compared to those packed in cans.
*Corresponding author: 
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