Aldehyde reactivity with 2-thiobarbituric acid and TBARS in.pdf

Aldehyde reactivity with 2-thiobarbituric acid and TBARS in freeze-dried beef during accelerated storage Q. Sun a, C. Faustman a,*, A. Senecal b, A.L. Wilkinson a,1, H. Furr c aDepartment of Animal Science, University of Connecticut, 3636 Horsebarn Road, Storrs, CT 06269-4040, USA bUS Army Natick RDE Center, MA 01760, USA cDepartment of Nutritional Sciences, University of Connecticut, 3636 Horsebarn Road, Storrs, CT 06269-4040, USA Received 1 February 2000; received in revised form 13 February 2000; accepted 13 June 2000 Abstract When lipid oxidation is evaluated in freeze-dried beef, a yellow 450-nm-absorbing pigment develops during the 2-thiobarbituric acid (TBA) assay. TBA analysis and high performance liquid chromatography (HPLC) were applied to measure oxidative changes in salted freeze-dried beef patties (15% fat) initially during storage at 49C. The TBA pink pigment (lmax=532 nm) was most pro- nounced in unstored salted freeze-dried beef, and yellow pigment (lmax=450 nm) predominated in stored samples. An in vitro study of TBA reactivity of di?erent aldehydes, known to be secondary lipid oxidation products, showed that alkanals and alk-2-enals favored TBARS450 formation, while alka-2,4-dienals favored TBARS532. Values of TBARS450 from 95 C TBA incubation were lower than those from 25C incubation (P0.05), indicating that the yellow chromophore from the aldehyde±TBA complex was less thermally stable than the pink pigment. 5-Hydroxymethyl-2-furfural, an aldehyde produced from Maillard reaction, also pro- duced strong TBARS450. Propional, butanal and 5-hydroxymethyl-2-furfural (HMF), were tentatively identi?ed in freeze-dried beef during accelerated storage at 49C, and have the potential to yield TBARS @450. # 2000 Elsevier Science Ltd. All rights reserved. Keywords: Thiobarbituric acid reactive substances (TBARS); Lipid oxidation; Dinitrophenylhydrazine; Aldehydes; Freeze-dried beef 1. Introduction One of the most important changes occurring during food prod