Assessing allergen levels in peach and nectarine cultivars.
ABSTRACT The lipid transfer protein Pru p 3 has been identified as a major peach fruit allergen. However, the putative peach member of the Bet v 1 family, Pru p 1, has been neither identified nor characterized.
To determine the distribution and solubility properties of the main peach allergens and to quantify Pru p 3 and Pru p 1 levels in peach and nectarine cultivars.
Peach peel and pulp were extracted using different buffers, and extracts were analyzed by means of sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunodetection using polyclonal antibodies against lipid transfer proteins, profilins, and Bet v 1 homologues. Pru p 3 was quantified in peach and nectarine cultivars using a sandwich enzyme-linked immunosorbent assay method. A similar method was developed to quantify Pru p 1.
A differential distribution between peel and pulp and different solubility properties were found for Pru p 3, Pru p 1, and peach profilin. Mean Pru p 3 levels were 132.86, 0.61, and 16.92 microg/g of fresh weight of peels, pulps, and whole fruits, respectively. The corresponding mean Pru p 1 levels were 0.62, 0.26, and 0.09 microg/g of fresh weight. Most US cultivars showed higher levels of both allergens than Spanish cultivars.
The different distribution and solubility properties of the main peach allergens can determine the quality of fruit extracts used as diagnostic tools. These differences, together with the natural variation of Pru p 3 and Pru p 1 levels among peach and nectarine cultivars, can be exploited to reduce peach allergenicity by means of industrial processing and plant breeding.
SourceAvailable from: rheumatologynews.com02/2008; 7(2):34-34. DOI:10.1016/S1541-9800(08)70075-9
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ABSTRACT: Mal d 1 is not equally distributed over the apple. We aimed to examine the influence of the location of pricking in the apple on prick-to-prick skin prick test (PTP) results. PTPs were performed in autumn 2007 and spring 2008, before the birch pollen season, in 32 Dutch adults with symptoms of oral allergy to fresh apple, using apples harvested in autumn 2007. PTPs with fresh intact and unpeeled Pink Lady, Golden Delicious, Elise, Santana and Modi apples were performed using material obtained from approximately 2 cm near the stalk (top), and the middle region. All PTP responses were greater when performed with apple material near the stalk than from the middle region. In 2007, these differences were statistically significant for Pink Lady, Golden Delicious and Elise, and in 2008, for Pink Lady and Modi. When performing PTPs, the apple should be pricked near the stalk rather than in the middle.Allergy 08/2013; 68(9). DOI:10.1111/all.12201 · 6.00 Impact Factor
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ABSTRACT: Lipid transfer proteins (LTPs) are a class of low molecular weight hydrophobic conserved proteins comprising four intramolecular disulphide bonds making the structure very resistant to proteolysis and harsh food processing conditions. These proteins are identified as strong allergens sensitizing through the gut and share epitopes with LTPs from closely related species. Peach LTP, Pru p 3 is the primary sensitizer in the Mediterranean area being the most frequent food allergen. Wheat LTP, Tri a 14 is a relatively weak allergen with a very low prevalence. The study here compares the structural properties of these proteins and their resistance to various digestive and processing processes. Ligand binding experiments showed that Pru p 3 binds to ligands more strongly than Tri a 14. The gastroduodenal digestion of these LTPs revealed that both are stable to gastric digestion and while Pru p 3 is susceptible to duodenal digestion, Tri a 14 digestion is negligible. Ligand binding did not affect the digestibility of Pru p 3 but improved the duodenal digestibility of Tri a 14. The IgE binding studies using sera from peach allergic individuals confirmed that both Pru p 3 and its digestion fragments in the presence and absence of ligand were IgE reactive. Model processing conditions were employed to treat these LTPs. It was found that heat treatment destroys the secondary structure of Pru p 3 at 121°C and slightly affects that of Tri a 14. Heat treatment also increased the susceptibility of Pru p 3 to gastric digestion while Tri a 14 was less affected. The IgE binding studies showed that heat treatment of Pru p 3 appeared to reduce its IgE recognition while its digestion fragments lost all of their IgE reactivity. To investigate the effect of the food matrix on the digestibility of these LTPs, peach peel containing Pru p 3 and wheat flour containing Tri a 14 were digested under simulated conditions. It was found that they were resistant to proteolysis in their native matrices. Effect of heat treatment to the food matrix again confirmed that both of these proteins were more stable to heat in the matrix and were less digestible. In conclusion, this study shows that there are factors in food matrices which enhance structural stability of LTPs to both processing and digestion. Thus factors such as the effect of food matrix and effect of processing should be taken into account in assessing the allergenic risk posed by foods and not simply rely on data from purified proteins.02/2012, Degree: PhD, Supervisor: Prof. Clare Mills