Czech J. Food Sci., 2018, 36(1):16-21 | DOI: 10.17221/297/2017-CJFS

Identification of biphenyls - contaminants responsible for off-flavour in soft drinksFood Chemistry and Safety

Iveta ŠÍSTKOVÁ, Vojtěch KRUŽÍK, Aleš RAJCHL, Helena ČÍŽKOVÁ

Department of Food Preservation, Faculty of Food and Biochemical Technology, University of Chemistry and Technology Prague, Prague, Czech Republic

Off-flavour in soft drinks is one of the main threats to manufacturers, which can result in expensive recalls, and discredit the brand. Off-flavours can occur for a variety of reasons (e.g . chemical contamination of raw material). The presented case study has proved there is a relationship between the identification of biphenyl and its derivatives in the used preser vative (benzoate) and off-flavours in the drink . The project consisted of three phases: (1) the assessment of the probable cause of off-f lavours based on sensor y evaluation and GC-MS -Olfactometr y profiling of volatiles; (2) the quantification of biphenyls and the characterisation of their sensor y properties; (3) the screening of commercially available benzoates for the presence of biphenyls. Based on the odour threshold obtained by GC-O (0.03 mg/l for 4-methyl-1,1'-biphenyl and 0.02 mg/l for biphenyl in an aqueous solution) and the common benzoate content in soft drinks (0.14 g/l), the 'non-obser vable sensory' levels of contamination were determined to be maximally 0.143 mg/g of benzoate for biphenyl and 0.214 mg/g of benzoate for 4-methyl-1,1 '-biphenyl .

Keywords: taint; non-alcoholic beverages; olfactometry; preservatives; sensory defects; sodium benzoate

Published: February 28, 2018  Show citation