title: Impact of green tea extract addition on oxidative changes in the lipid fraction of pastry products.
abstract: BACKGROUND
  Alongside flour, fat is the key ingredient of sponge cakes, including those with long shelf lives. It is an unstable food component, whose quality and nutritional safety depend on the composition and pres- ence of oxidation products. Consumption of fat oxidation products adversely affects the human body and contributes to the incidence of a number of medical conditions. Qualitative changes in fats extracted from thermostat sponge cakes with and without antioxidant additions were determined in this study.
  
  
  METHODS
  In the study, two types of antioxidant were used: natural - green tea extract in three doses (0.02%; 0.2% and 1.0%) and synthetic BHA (0.02%) and 100%, solid bakery shortening. Sponge-cakes were thermostatted at temperatures 63°C after twenty-eight days. In this study, the quality of the lipid fraction was analyzed. The amount of primary (PV) and secondary (AnV) oxidation products was determined, and   a Rancimat test was performed.
  
  
  RESULTS
  Adding antioxidants to fats varied in the degree to which oxidation processes of lipids fractions were inhibited. The peroxide value after twenty-eight days of thermostatting ranged from 3.57 meq O/kg (BHA) and 11.14 O meq/kg (extract content - 1%) to 62.85 meq O/kg (control sample). In turn, the value of AnV after the storage period ranged from 4.84 (BHA) and 6.71 (extract content - 1%) to 16.83 (control sample).
  
  
  CONCLUSIONS
  The best protective effects in the process of oxidation was achieved by BHA. The longest in- duction time and the lowest peroxide value and anisidine value were obtained for this antioxidant. It was achieved after twenty-eight days of fat thermostatting. Nonetheless, the results demonstrated it is possible to use the commercially available green tea extract to slow the adverse process of fat oxidation in sponge cake products.
authors.affiliation: Department of Food Technology, Warsaw University of Life Sciences &#; SGGW, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Żbikowska
authors.affiliation: Department of Chemistry, Kazimierz Pulaski University of Technology and Humanities in Radom, Poland.
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Kowalska
authors.affiliation: Department of Instrumental Analysis, Warsaw University of Life Sciences &#; SGGW, Poland.
authors.forename: Jarosława
authors.initials: J
authors.lastname: Rutkowska
authors.affiliation: Department of Instrumental Analysis, Warsaw University of Life Sciences &#; SGGW, Poland.
authors.forename: Mariola
authors.initials: M
authors.lastname: Kozłowska
authors.affiliation: Department of Food Technology, Warsaw University of Life Sciences &#; SGGW, Poland.
authors.forename: Sylwia
authors.initials: S
authors.lastname: Onacik-Gür
mesh_terms: D000975:Antioxidants / Q000737:chemistry*; D005502:Food; D008055:Lipids / Q000737:chemistry*; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D010936:Plant Extracts / Q000737:chemistry*; D013662:Tea / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D008055:Lipids; D010936:Plant Extracts; D013662:Tea
keywords: green tea extract; oxidation products; oxidative stability; sponge cakes