49I-6 |
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J.-Y. YEH, F. K. Saalia, and R. D. Phillips. Dept. of Food Science & Technology, Univ. of Georgia, 1109 Experiment St., Melton Bldg., Griffin, GA 30223-1797 Peanuts are among the most common food allergens. While most processing methods fail to reduce and may even increase the allergenic potential of peanut proteins, extrusion with its combination of high shear, temperature and pressure severely denatures peanut proteins and may reduce allergenicity. The objective was to investigate whether extrusion processing can reduce allergenicity of peanut using a competitive ELISA method. Defatted (1% fat) light roasted and dark roasted peanut flour were extruded (APV-Baker co-rotating twin-screw extruder) under three conditions, mild (35% moisture, barrel temperature 120°C, screw speed 300 rpm), medium (30% moisture, barrel temperature 140°C, screw speed 400 rpm), and severe (25% moisture, barrel temperature 160°C, screw speed 500 rpm). Samples were extracted with 20 mM Tris buffer (pH 8.2) – 0.5% SDS. Extracts were analyzed for protein solubility using a dye binding procedure, subunit profiles using SDS-PAGE, and for allergenic potential by inhibition ELISA using serum from patients with documented peanut allergy. Protein solubility ranged from 32 to 96%, being highest in flours and lowest in mild extrudates with more severe extrusion conditions restoring some-to-all of the original solubility. However, SDS-PAGE showed that extrusion reduced the amounts of original, especially higher MW, subunits such as the 66kD putative Ara h1 and increased background smearing. Unextruded peanut flour extracts had a ten fold higher ability to bind IgE than extruded extracts on an equal protein basis. The concentrations of competitor sample (free antigen) required to inhibit IgE binding to coated wells by 50% (IC50) were 3.19 ug/ml for light roasted flour and 2.87 ug/ml for dark roasted flour. After extrusion, IC50 increased to 37.61 ug/ml (mild), 67.03 ug/ml (medium), and 49.85 ug/ml (severe) for light roasted peanut, 55.48 ug/ml (mild), 116.80 ug/ml (medium) and 184.83 ug/ml (severe) for dark roasted peanut. Extrusion cooking may reduce allergenicity in peanuts
Session 49I, Toxicology & Safety Evaluation: General
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