59D-17 |
Influence of food processing on the antigenicity of almond proteins |
M. VENKATACHALAM1, K. H. Roux2, and S. K. Sathe1. (1) Department of Nutrition, Food and Exercise Sciences, Florida State University, 402 Sandels Bldg., College of Human Sciences, Tallahassee, FL 32306-1493, (2) Department of Biological Science, Florida State University Tree nuts are one of the major causative agents of food allergies. Almonds being one of the most popular among tree nuts, antigenic characterization of almond proteins, especially under various food processing conditions, is important. The aim of the present study was to investigate the immunoreactivity of almond proteins subjected to different heat processing methods. Whole, unprocessed Nonpareil almonds were subjected to heat processing methods: roasting (280, 300, and 320 oF for 20 and 30 min each and 335 & 350oF for 8, 10 and 12 min each), autoclaving (121oC, 15 psi, for 5, 10, 15, 20, 25 and 30 min), blanching (100oC for 1, 2, 3, 4, 5 and 10 min) and microwave heating (1, 2, 3 and 4 min). Almond proteins were extracted from defatted almond flour in borate saline buffer (BSB, 0.1M, pH 8.45) and immunoreactivity of the soluble proteins (normalized to 1 mg/ml for all samples) was determined using enzyme linked immunosorbent assay (ELISA). Antigenic stability of almond major protein (AMP) in the heat processed samples was determined by competitive inhibition ELISA using rabbit polyclonal antibodies raised against the purified AMP. Processed samples were also assessed for heat stability of total antigenic proteins by sandwich ELISA using goat and rabbit polyclonal antibodies raised against unprocessed Nonpareil almond total protein extract. Immunoreactivity of the processed samples was expressed as ratio (R) of IC50 of processed sample to IC50 of unprocessed sample. Heat processing did not reduce immunoreactivity of almond proteins with the exception of roasting at 350oF for 30 min(R~ 3) and microwave treatment at 3 and 4 min (R ~3-14). The results of these studies suggest that simple heat processing does not significantly reduce antigenicity of almond proteins.
Session 59D, Food Chemistry: Proteins and Physicochemical Properties
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