Determination of Benzoyl Peroxide and Benzoic Acid Levels by HPLC during Wheat Flour Bleaching Process

Abstract

Freshly milled wheat flour has a pale yellow color due to its carotenoids content. Benzoyl peroxide is a bleaching agent typically used to give such flour a better appearance. This free-radical initiator promotes carotenoids oxidation, thereby producing less colored compounds, and benzoic acid is a main final product. Samples of wheat flour were treated with 150 ppm of benzoyl peroxide to begin a bleaching process, and then subjected to ethyl ether extraction at different intervals of time. Benzoyl peroxide and benzoic acid levels in these extracts were monitored by means of HPLC in individual experiences. The resulting concentration of benzoyl peroxide after 9 days of contact with the bleaching agent was 11 ppm, dropping afterward to nondetectable levels. A maximum value for benzoic acid of 16 ppm was found after 12 h of bleaching. Subsequently this level decreased continuously until reaching a residual value of 6 ppm after 3 months.

Evaluation the quality characteristics of wheat flour and shelf-life of fresh noodles as affected by ozone treatment

“…Freshly milled wheat flour usually presents a pale yellow colour, due to the naturally existed yellow pigments, in particular carotenoids, which include b-carotene, xanthophyll, and flavones (Saiz, Manrique, & Fritz, 2001). This results in noodle products (especially white salted noodles) with a colour that is less commercially acceptable.…”

“…This results in noodle products (especially white salted noodles) with a colour that is less commercially acceptable. Benzoyl peroxide is the most common flour-bleaching agent used by the industry, by disrupting the conjugated double-bond system of carotenoid to a less conjugated colourless system and producing the bleaching effect (Saiz et al, 2001). Residual levels of both benzoyl peroxide and its reaction product benzoic acid can create safety and environmental hazards.…”

Assessment of benzoic acid levels in milk in China

“…To achieve such a purpose, many methods have been published, such as high performance liquid chromatography (HPLC), UV spectroscopy, gas chromatography (GC) and GC-MS. Owning to high specificity and minimum sample preparation, HPLC has been the most common method for the analysis of benzoic acid and its salt in foods (Jr & Grether, 2000;Saiz, Manrique, & Fritz, 2001;Tfouni & Toledo, 2002).…”

Effect of an enzyme preparation on wheat flour and dough color, mixing, and test baking

“…Freshly milled wheat flour has a pale yellow tint, with pigmentation in amounts of 1.5-4 mg/kg expressed as carotenoid (Pyler, 1988a). During flour storage, reactions occur between flour components, especially unsaturated lipids, and oxygen in a process known as aging or maturing (Saiz, Manrique, & Fritz, 2001). This process gradually whitens the flour over time and renders dough with improved rheological and baking qualities.…”

“…This process gradually whitens the flour over time and renders dough with improved rheological and baking qualities. This improvement and whitening effect are direct consequences of oxidative reactions (Saiz et al, 2001). Whiter flour is preferred in pan white bread baking because it results in better crumb color.…”