Scientific journal

49 2010

Journal of Food and Nutrition Research
Summary No. 2 / 2010

Catechin stability, antioxidant properties and sensory profiles of rye breads fortified with green tea extracts
Journal of Food and Nutrition Research, 49, 2010, No. 2, s. 104-111

Joanna Bajerska, Department of Human Nutrition and Hygiene, Poznan University of Life Sciences, Wojska Polskiego 31, 60-624 Poznan, Poland. Tel. 0048 61 846 60 56, fax: 0048 61 848 73 32, e-mail:

Summary: The effect of green tea extracts (GTE) on catechin stability, antioxidant properties and sensory profiles were analysed in rye breads (RB). The following samples of RB were prepared: control bread (C), breads with 0.5, 0.8 and 1.1% of GTE, respectively. Separation, identification and quantification of GTE catechins were achieved by HPLC. Antioxidant properties were measured by the method of radicals coloured by 2,2-diphenyl-1-picrylhydrazyl (DPPH). Sensory quality of breads was determined using a hedonic test. The most stable catechins were as follows: epigallatocatechin (EGC) < < epigallatocatechin gallate (EGCG) < epicatechin gallate (ECG), and detectable amounts increased with an increase in the level of GTE added to RB. The antioxidant effectiveness decreased in the order 1.1% GTE > 0.8% GTE > 0.5% GTE > C. Sensory characteristics, such as scores for aroma, flavour and overall acceptability, decreased significantly (in comparison to C) when RB was prepared with 1.1% GTE. Rye bread with 1.1% GTE was good in terms of antioxidant properties. However, due to changes in sensory properties, the level of GTE powder incorporated to bread should be limited to 0.8% or bread making technology with high levels of GTE should include addition of flavour-masking additives.

Keywords: bread; green tea extracts; sensory evaluation; polyphenol content; antioxidant capacity

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