Soy isoflavones have been a component of the diet of certain populations for centuries. The consumption of soy generally has been considered beneficial, with a potentially protective effect against a number of chronic diseases; because of their estrogenic activity, however, negative effects of isoflavones have been postulated. This review examines the literature associated with the safety of soy isoflavones, including dietary soy isoflavone exposure data of populations with high soy intakes, human studies in which soy protein or isoflavones were provided, and toxicologic studies investigating the potential genotoxicity, carcinogenicity, and reproductive and developmental toxicity of soy isoflavones. Whereas results in some studies are limited or conflicting, when viewed in its entirety, the current literature supports the safety of isoflavones as typically consumed in diets based on soy or containing soy products.
Fumonisins, mycotoxins produced by Fusarium moniliforme in corn, have been implicated in several animal and human diseases. The effects of processing time and temperature on fumonisin B 1 (FB 1 ) stability (5 ppm) in aqueous solutions at pH 4, 7, and 10 were determined. Analysis of the thermally processed solutions by liquid chromatography/mass spectrometry indicated the predominant presence of hydrolysis products of FB 1 . The rate and extent of FB 1 decomposition increased with processing temperature. After processing at e125 °C for 60 min, <27% of FB 1 was lost; after 60 min at 150 °C, 18-90% was lost, depending on buffer pH. Overall, FB 1 was least stable at pH 4 followed by pH 10 and 7, respectively. At g175 °C, >90% of FB 1 was lost after processing for 60 min, regardless of pH. FB 1 levels may be substantially reduced in foods that reach g150 °C during processing.
Background: Sunflower seed can cause severe anaphylactic reactions in some susceptible individuals. It is conceivable that the 2S sunflower seed protein is an allergen based on its high degree of homology (34%) with the allergenic mature 2S albumin protein of the Brazil nut. The first step in determining the allergenicity of sunflower seed proteins is to identify IgE-binding proteins. Methods: Sera from sunflower seed-sensitive individuals were evaluated by radioallergosorbent test (RAST), isoelectric focusing (IEF) and sodium dodecyl sulfate-polyacrylamide gel electrophoresis immunoblotting with sunflower seed proteins. Results: Positive RAST scores (>2) were observed in 3 individuals and immunoblotting demonstrated IgE-binding to 2–7 distinct proteins ranging in size from 10 to 50 kD. Two out of 3 sera recognized two proteins between 16 and 17 kD. The lower molecular weight protein (16 kD) approximates to the prepo region of the precursor methionine-rich 2S albumin protein found in sunflower seed (SFA-8/SSA). IEF followed by immunoblotting demonstrated several IgE-binding proteins, including two proteins with isoelectric points of 5.97 and 5.3, respectively, which are consistent with the mature and immature forms of the SFA-8/SSA region. Conclusions: Sunflower seed contains several IgE-binding proteins, including regions of the high-methionine 2S albumin SFA-8/SSA.
An enzyme-linked immunosorbent assay was developed to detect almonds as potential allergenic contaminants in food. Polyclonal antibodies directed against roasted almonds were partially purified from immunized sheep and rabbits and used as capture and secondary antibodies, respectively, in a sandwich-type, 96-well plate format. Food samples and almond-spiked samples were extracted 1:10 in phosphate-buffered saline at 60 degrees C for 2 h, centrifuged, and applied to wells coated with sheep anti-almond antibody. After incubation, washing, and the addition of rabbit anti-almond antibody, the amount of almond present was detected with the subsequent addition of goat anti-rabbit immunoglobulin G-alkaline phosphatase conjugate and p-nitrophenyl phosphate substrate. Plate absorbances were read at 410 nm, and standard curves were developed in all matrices to quantify unknowns. Antibodies developed were specific for almond; however, some cross-reactivity was observed with extracts of some tree nuts and sesame seeds. Sodium dodecylsulfate-polyacrylamide gel electrophoresis and Western immunoblotting indicated that sheep anti-almond antibody recognized proteins extracted from black walnuts, Brazil nuts, cashews, hazelnuts, macadamia nuts, pistachios, and sesame seeds in addition to those from almond. The assay was optimized to detect less than 1 ppm of almond and was used successfully to determine almond residues in cereal and chocolate without cross-reacting interferences. A retail survey of 20 brands of cereal demonstrated that the assay produced statistically consistent results. This assay provides a useful quality control tool for the food industry for the protection of consumers allergic to almonds.
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