Improved qualitative properties of pear pekmez by natural zeolite treatment during production process

The effect of zeolite treatment on color change, 5-hydroxymethyl furfural (HMF), total phenolic compounds (TPCs), ionic composition and texture of sweet pear pekmez was investigated for two different zeolite concentrations during pekmez production. HMF was not detected in clarified pear juice and pekmez samples subjected to 5 g/L (5ZP) and 10 g/L (10ZP) zeolite adsorption. HMF content of pekmez sample without zeolite treatment (PP) was measured as 2.76 +/- 0.07 mg/kg. The addition of zeolite just after the clarification results in the reduction of the HMF content of pekmez samples. The highest TPC was determined as 4,958.1 +/- 167 mg GAE/kg dry weight in PP sample. Application of zeolite together with conventional clarification resulted in 31.4% and 33.2% reduction in TPC of 5ZP and 10ZP, respectively, compared to PP samples. Zeolite application improved the color quality of pekmez samples. While the amount of fluoride, chloride, bromide, and potassium decreased with the zeolite treatment, the amount of calcium, sodium and magnesium in pekmez samples increased significantly. Zeolite treatment did not significantly affect the texture of the samples. Practical applications Pekmez is concentrated fruit juice with long shelf life and high nutritional value. HMF formation is a very important problem that must be prevented or eliminated in the pekmez production process. This study provides the pear pekmez production process and determination of some important quality features such as color change and amount of HMF and metal ions. Besides, zeolite treatment is applied for the first time during pekmez processing. The results reveal that zeolite treatment is useful means to reduce undesirable metal ions and HMF formation during pekmez production while improving the color quality. Consequently, the use of zeolite in pekmez production has great potential to produce the high quality and safe pear pekmez.