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Biosensor immunoassay for traces of hazelnut protein in olive oil.

Bremer MG, Smits NG, Haasnoot W - Anal Bioanal Chem (2009)

Bottom Line: The fraudulent addition of hazelnut oil to more expensive olive oil not only causes economical loss but may also result in problems for allergic individuals as they may inadvertently be exposed to potentially allergenic hazelnut proteins.To improve consumer safety, a rapid and sensitive direct biosensor immunoassay, based on a highly specific monoclonal antibody, was developed to detect the presence of hazelnut proteins in olive oils.Recoveries obtained with an olive oil mixed with different amounts of a hazelnut protein containing hazelnut oil varied between 93% and 109%.

View Article: PubMed Central - PubMed

Affiliation: RIKILT-Institute of Food Safety, Wageningen UR, P.O. Box 230, 6700 AE Wageningen, The Netherlands. monique.bremer@wur.nl

ABSTRACT
The fraudulent addition of hazelnut oil to more expensive olive oil not only causes economical loss but may also result in problems for allergic individuals as they may inadvertently be exposed to potentially allergenic hazelnut proteins. To improve consumer safety, a rapid and sensitive direct biosensor immunoassay, based on a highly specific monoclonal antibody, was developed to detect the presence of hazelnut proteins in olive oils. The sample preparation was easy (extraction with buffer); the assay time was fast (4.5 min only) and the limit of detection was low (0.08 microg/g of hazelnut proteins in olive oil). Recoveries obtained with an olive oil mixed with different amounts of a hazelnut protein containing hazelnut oil varied between 93% and 109%.

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Calibration curve of hazelnut proteins in an extract of pure olive oil as obtained with the direct BIA. Samples were measured in duplicate and standard deviations are shown as error bars
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Fig3: Calibration curve of hazelnut proteins in an extract of pure olive oil as obtained with the direct BIA. Samples were measured in duplicate and standard deviations are shown as error bars

Mentions: A calibration curve was constructed by plotting the concentrations of hazelnut protein (0–5 μg/mL) in extracts of pure extra virgin olive oil against the responses in the biosensor (Fig. 3). The response in the antihazelnut-coated Fc increased linearly with hazelnut protein concentration up to a concentration of 2.5 μg/mL. At a concentration of 5 μg/mL, the signal slightly leveled off. For reasons of accuracy, we used the linear calibration curve between 0 and 2.5 μg/mL. The limit of detection (LOD) of the assay was determined by analyzing eight different blank olive oils obtained from local markets in The Netherlands and Greece. Due to the applied extraction procedure (2.5 g of oil with 2.5 mL of extraction buffer), the concentrations of hazelnut proteins in the oil (μg/g) are similar to the concentrations in the extraction buffer (μg/mL). An LOD, defined as the concentration corresponding to the average signal from blank samples plus three standard deviations, of 0.08 μg/g was determined. This LOD is in the same range as commercially available ELISA kits and as the biosensor assay described previously [14]. To increase food safety for hazelnut-allergic individuals, analytical methods should be able to detect at least 1–2 μg/g of hazelnut protein in a foodstuff. In this way, only mild or no allergic reactions are to be expected [7]. Obviously, our BIA meets this requirement.Fig. 3


Biosensor immunoassay for traces of hazelnut protein in olive oil.

Bremer MG, Smits NG, Haasnoot W - Anal Bioanal Chem (2009)

Calibration curve of hazelnut proteins in an extract of pure olive oil as obtained with the direct BIA. Samples were measured in duplicate and standard deviations are shown as error bars
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2724632&req=5

Fig3: Calibration curve of hazelnut proteins in an extract of pure olive oil as obtained with the direct BIA. Samples were measured in duplicate and standard deviations are shown as error bars
Mentions: A calibration curve was constructed by plotting the concentrations of hazelnut protein (0–5 μg/mL) in extracts of pure extra virgin olive oil against the responses in the biosensor (Fig. 3). The response in the antihazelnut-coated Fc increased linearly with hazelnut protein concentration up to a concentration of 2.5 μg/mL. At a concentration of 5 μg/mL, the signal slightly leveled off. For reasons of accuracy, we used the linear calibration curve between 0 and 2.5 μg/mL. The limit of detection (LOD) of the assay was determined by analyzing eight different blank olive oils obtained from local markets in The Netherlands and Greece. Due to the applied extraction procedure (2.5 g of oil with 2.5 mL of extraction buffer), the concentrations of hazelnut proteins in the oil (μg/g) are similar to the concentrations in the extraction buffer (μg/mL). An LOD, defined as the concentration corresponding to the average signal from blank samples plus three standard deviations, of 0.08 μg/g was determined. This LOD is in the same range as commercially available ELISA kits and as the biosensor assay described previously [14]. To increase food safety for hazelnut-allergic individuals, analytical methods should be able to detect at least 1–2 μg/g of hazelnut protein in a foodstuff. In this way, only mild or no allergic reactions are to be expected [7]. Obviously, our BIA meets this requirement.Fig. 3

Bottom Line: The fraudulent addition of hazelnut oil to more expensive olive oil not only causes economical loss but may also result in problems for allergic individuals as they may inadvertently be exposed to potentially allergenic hazelnut proteins.To improve consumer safety, a rapid and sensitive direct biosensor immunoassay, based on a highly specific monoclonal antibody, was developed to detect the presence of hazelnut proteins in olive oils.Recoveries obtained with an olive oil mixed with different amounts of a hazelnut protein containing hazelnut oil varied between 93% and 109%.

View Article: PubMed Central - PubMed

Affiliation: RIKILT-Institute of Food Safety, Wageningen UR, P.O. Box 230, 6700 AE Wageningen, The Netherlands. monique.bremer@wur.nl

ABSTRACT
The fraudulent addition of hazelnut oil to more expensive olive oil not only causes economical loss but may also result in problems for allergic individuals as they may inadvertently be exposed to potentially allergenic hazelnut proteins. To improve consumer safety, a rapid and sensitive direct biosensor immunoassay, based on a highly specific monoclonal antibody, was developed to detect the presence of hazelnut proteins in olive oils. The sample preparation was easy (extraction with buffer); the assay time was fast (4.5 min only) and the limit of detection was low (0.08 microg/g of hazelnut proteins in olive oil). Recoveries obtained with an olive oil mixed with different amounts of a hazelnut protein containing hazelnut oil varied between 93% and 109%.

Show MeSH