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Title:Effects of packaging and soy protein isolate antioxidant on lipid oxidation of ground beef
Author(s):Wu, Shunyong
Doctoral Committee Chair(s):Brewer, Mary S.
Department / Program:Human and Community Development
Discipline:Human and Community Development
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Agriculture, Food Science and Technology
Abstract:Ground beef chunk (15% fat) was packaged (500 g) in vacuum bags, Saran Wrap$\sp{\rm TM}$ overwrapped with aluminum foil or polyvinyl chloride (PVC), exposed to retail display light (4$\sp\circ$C) for 24 h and then held frozen ($-$18$\sp\circ$C) for 52 weeks. Instrumental and visual color of PVC-packaged beef was damaged most by display and by frozen storage. During frozen storage, as oxygen permeability of packaging material increased, TBA value, visual brownness, and metmyoglobin increased while visual redness, acceptability, a* value, red color contributed by oxymyoglobin, and deoxymyoglobin decreased. Location on the meat block (exterior vs interior) affected (p $<$ 0.05) visual red and brown color, color lightness, and acceptability, L*, a*, and b* values, and TBA value.
A variety of substances was evaluated for antioxidant or prooxidant activity in an aqueous model system of linoleic acid, Triton-X100, and 2-thiobarbituric acid solidified with agar in a Petri plate. Test samples were applied to wells cut from media. The oxidation reaction was initiated with ferric/ferrous chloride (50 mM/50 mM). Quantitative data were obtained by determining the diameter of the reaction ring surrounding test substance. Test substances and linoleic acid were oxidized, then subjected to the 2-thiobarbituric acid (TBA) test for comparison. Simulated food systems were also tested using both systems. Correlation coefficients between the test method (inverse ring diameter, cm) and nmol malondialdehyde/mL measured by the TBA test were r = 0.98, 0.90, and 0.91 for BHA, vitamin E and C, respectively.
Soy protein isolate antioxidant (SPLA) was isolated from soy protein, fractionated (Sephadex G15), and purified (TLC). Quite a few phenolic compounds, including chlorogenic acid, caffeic acid, rutin, quercetin, probably genistein and daidzein were present in the SPIA preparation. SPIA (300 or 900 ppm) was added to a ground beef model system; oxidation was initiated by adding Fe$\sp{2+}$/Fe$\sp{3+}$, vials were sealed and stored at 4$\sp\circ$C for 0, 8, 16 and 24 h. Oxidation products were assessed using the TBA test, sensory analysis (odor), gas chromatographic separation and mass spectrometric identification of selected headspace volatiles. SPIA (900 ppm) was also added to beef microsomal protein model system and treated as described above. Beef samples containing 900 ppm SPIA had lower TBA numbers, less rancid odor, less hexanal and total volatiles after 16 and 24 h than did samples containing 300 ppm SPIA and controls. The beef microsomal system containing 900 ppm SPIA followed similar trends.
Issue Date:1994
Rights Information:Copyright 1994 Wu, Shunyong
Date Available in IDEALS:2011-05-07
Identifier in Online Catalog:AAI9416453
OCLC Identifier:(UMI)AAI9416453

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