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Murat Ozdemir - One of the best experts on this subject based on the ideXlab platform.
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a review on grain and nut deterioration and design of the dryers for safe storage with special reference to turkish Hazelnuts
Critical Reviews in Food Science and Nutrition, 2001Co-Authors: Mustafa Ozilgen, Murat OzdemirAbstract:Turkey produces about 80% of the total hazelnut crop of the world. About 75% of the production are exported. In Turkey Hazelnuts are traditionally sun dried, and may be subject to mold growth and subsequent mycotoxin formation due to prolonged drying time under humid and rainy weather conditions. Drying Hazelnuts in a reasonable time after harvest is necessary for mycotoxin-free, high-quality products. In general, nuts and cereals contaminated by the toxins pose a potential hazard not only to the people of the producer countries, but also to people of the importing countries, if they should be regarded as safe by inefficient sampling plans, therefore preventing toxin formation actually benefits very large populations. Deterioration and health hazards associated with toxin contaminated Hazelnuts and other nuts and cereals have similar causes and consequences; therefore, deterioration of the nuts and cereals in storage has been reviewed by considering as many grains and nuts as possible, then special reference was made to Hazelnuts. Proper preharvest practices followed by proper drying and safe storage reduces the hazards associated with contamination by the toxins. This article reviews the pre- and post-harvest practices, and the grain- and nut-drying systems required for toxin-free products. Because drying is the major unit operation involving this process, the drying systems and the mathematical models required for their design is also discussed.
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analysis of color development during roasting of Hazelnuts using response surface methodology
Journal of Food Engineering, 2000Co-Authors: Murat Ozdemir, Onur DevresAbstract:Hazelnut roasting was analyzed using response surface methodology to find out the effect of process variables on color development during roasting and to establish prediction models. The roasting temperature was found to be the main factor affecting color development. Developed prediction models satisfactorily described color development as a function of roasting temperature and exposure time for L-value, a-value and b-value of whole-kernel, ground-state and cut-kernel measurements. Whole-kernel measurements were significantly lighter in color compared to ground-state and cut-kernel measurements due to internal browning of the Hazelnuts during roasting. The results also indicated that the L-value of ground-state measurements, which take into account internal browning during roasting, should be used to monitor roasting of Hazelnuts.
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Kinetics of color changes of Hazelnuts during roasting
Journal of Food Engineering, 2000Co-Authors: Murat Ozdemir, Onur DevresAbstract:Abstract Kinetics of color changes during hazelnut roasting was described for a temperature range of 100–160°C for 60 min. The rate of color changes was significantly affected by temperature and time over the experimental conditions. Roasted hazelnut samples produced significantly lower L -value and b -value in ground-state color measurements compared to whole-kernel measurements. The results showed that color changes during hazelnut roasting can be satisfactorily described by a third-degree polynomial with an Arrhenius-type temperature dependence of the model coefficients. Activation energy for the L -value of color was found to be 62.3 kJ/mol over the temperature range of the study. A generalized model for color changes during roasting of Hazelnuts as a function of temperature and time was established.
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EFFECT OF INITIAL MOISTURE CONTENT ON THE THIN LAYER DRYING CHARACTERISTICS OF Hazelnuts DURING ROASTING
Drying Technology, 2000Co-Authors: Murat Ozdemir, Ferda Seyhan, A. Özdeş Bodurb, Y. Onur DevresAbstract:ABSTRACT Effect of initial moisture content on the thin layer drying characteristics of Hazelnuts during roasting was described for a temperature range of 100-160°C, using several thin layer equations. The effective diffusivity varied from 2.8×10−7 to 21.5×10−7m2/s over the temperature and moisture range. Temperature dependence of the diffusivity coefficient was described by Arrhenius-type relationship. The activation energy for moisture diffusion was found to be 2703 kJ/kg, 2289 kJ/kg and 2030 kJ/kg for the initial moisture content of 12.3% db, 6.14% db, and 2.41% db, respectively. Two-term equation gave better predictions than Henderson and Pabis and Thompson equations, and satisfactorily described thin layer drying characteristics of hazelnut roasting. A generalised mathematical model with the linear temperature dependence for moistured, non-treated and pre-dried Hazelnuts were also developed.
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the thin layer drying characteristics of Hazelnuts during roasting
Journal of Food Engineering, 1999Co-Authors: Murat Ozdemir, Onur Y DevresAbstract:Thin layer drying characteristics of Hazelnuts during roasting were described for a temperature range of 100–160°C, using five semi-theoretical and two empirical thin layer models. The effective diffusivity varied from 2.301×10−7 to 11.759×10−7 m2/s over the temperature range. Temperature dependence of the diffusivity coefficient was described by Arrhenius-type relationship. The activation energy for moisture diffusion was found to be 1891.6 kJ/kg. Thin layer drying characteristics of hazelnut roasting were satisfactorily described by an empirical Thompson model with the linear temperature dependence.
Marco Arlorio - One of the best experts on this subject based on the ideXlab platform.
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application of 1h nmr for the characterisation and authentication of tonda gentile trilobata Hazelnuts from piedmont italy
Food Chemistry, 2014Co-Authors: Augusta Caligiani, Jean Daniel Coisson, Fabiano Travaglia, Domenico Acquotti, Gerardo Palla, Luigi Palla, Marco ArlorioAbstract:The Italian hazelnut (Corylus avellana cultivar "Tonda Gentile Trilobata" (TGT) is covered by protected geographical indication "Nocciola Piemonte" and is well-known as the best-suited hazelnut for the industrial transformation into roasted kernel. The hazelnut cultivar identification is primarily based on morphological characteristics, so there is the need for more objective analytical methods for high quality hazelnut authentication. This study reports the H-1 NMR fingerprinting of raw and roasted hazelnut, with the aim of obtaining hazelnut classification based on their spectroscopic pattern. H-1 NMR analyses were carried out on polar extracts of TGT and other cultivars: the data were analysed with multivariate statistical methods. Results showed that H-1 NMR combined with chemometrics is useful to characterise the Hazelnuts as a function of the cultivars, both on raw and roasted form. The classification models allowed identifying molecular markers useful to distinguish TGT from other types, among these trigonelline, amino acids and an unidentified orto-disubstituted aromatic compound. (C) 2013 Elsevier Ltd. All rights reserved.
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chemotype and genotype chemometrical evaluation applied to authentication and traceability of tonda gentile trilobata Hazelnuts from piedmont italy
Food Chemistry, 2011Co-Authors: Monica Locatelli, Jean Daniel Coisson, Fabiano Travaglia, Elisabetta Cereti, Cristiano Garino, Matteo Dandrea, A Martelli, Marco ArlorioAbstract:Italian Hazelnuts ‘‘Tonda Gentile Trilobata’’ cv are recognised as high quality products with good sensory characteristics and interesting technological properties. An approach was employed to identify the ‘‘Tonda Gentile Trilobata’’ Hazelnuts from Piedmont (Italy), differentiating them from other Hazelnuts belonging to a different cultivar and/or different geographic origin, on the basis of their chemical and genetic characteristics. Proximate composition, fatty acid profile, polyphenols content and fingerprint, antioxidant activity, and protein patterns were determined. Concerning the genetic analysis, RAPD (Random Amplified Polymorphism DNA) technique was employed to detect polymorphisms amongst different hazelnut samples. Principal Component Analysis (PCA) on the chemical and genomic data sets permitted to identify the ‘‘Tonda Gentile Trilobata’’ cv. The analysis of chemotype allowed differentiating the Chilean sample from the other ‘‘Tonda Gentile Trilobata’’ Hazelnuts, whilst no genetic differences were observed amongst these samples. On the other hand, genomic data confirmed that RAPD is able to discriminate amongst cultivars. The common hazel plant (Corylus avellana L.) is a shrub native to Europe and Asia and belongs to the family of Betulaceae, genus Corylus. It grows in temperate climates like Turkey, Spain, Italy and the USA. Italy is the second largest hazelnut producer in the world (13.5% of total output) ahead of the USA and behind Turkey. Hazelnut crops are spread all around the Italian territory located in specific areas, such as Piedmont region in the North, Viterbo province in the centre (Latium), Avellino province (Campania) and Sicilian region in the South. Hazelnuts in Italy are sold both as in-shell and shelled. In-shell Hazelnuts are generally sold as a snack for fresh consumption while shelled ones (both whole and milled nuts) are often used as raw material for confectionary and bakery food production. Approximately 90% of the Italian harvest goes to processing companies, whereas fresh consumption represents the remaining 10% (Baldi,
Lars K Poulsen - One of the best experts on this subject based on the ideXlab platform.
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roasted Hazelnuts allergenic activity evaluated by double blind placebo controlled food challenge
Allergy, 2003Co-Authors: Skamstrup K Hansen, Barbara Ballmerweber, Stefan Vieths, D Luttkopf, Per Stahl Skov, B Wuthrich, Carsten Bindslevjensen, Lars K PoulsenAbstract:Background: Allergy to Hazelnuts is a common example of birch pollen related food allergy. Symptoms upon ingestion are often confined to the mouth and throat, but severe systemic reactions have been described in some patients. The aim of the study was to evaluate the reduction in allergenicity by roasting of the nuts. Methods: Double-blind, placebo-controlled food challenges (DBPCFC) with roasted Hazelnuts (140°C, 40 min) were performed in 17 birch pollen allergic patients with DBPCFC-confirmed food allergy to raw Hazelnuts. The effect of roasting was further evaluated by skin prick test (SPT), histamine release (HR), measurement of specific IgE, and IgE-inhibition experiments. Results: In 5/17 patients the DBPCFC with the roasted nuts were positive. The symptoms were generally mild and included OAS (oral allergy syndrome) in all patients. Roasting of the nuts significantly reduced the allergenic activity evaluated by SPT, HR, specific IgE, and IgE-inhibition. Immunoblotting experiments with recombinant hazelnut allergens showed sensitization against Cor a 1.04 in 16/17 patients and against Cor a 2 in 7/17 patients. None of the patients were sensitized to Cor a 8. Challenge-positive patients did not differ from the rest in IgE-binding pattern. Conclusions: All the applied methods indicated that roasting of Hazelnuts reduces the allergenicity, but since 5/17 birch pollen allergic patients were DBPCFC-positive to the roasted nuts, ingestion of roasted Hazelnuts or products containing roasted Hazelnuts can not be considered safe for a number of hazelnut allergic consumers. For patients with a history of severe allergic symptoms upon ingestion of Hazelnuts, thorough and conscientious food labelling of Hazelnuts and hazelnut residues is essential.
Peter Schieberle - One of the best experts on this subject based on the ideXlab platform.
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characterization of the key odorants in raw italian Hazelnuts corylus avellana l var tonda romana and roasted hazelnut paste by means of molecular sensory science
Journal of Agricultural and Food Chemistry, 2012Co-Authors: Andrea Burdackfreitag, Peter SchieberleAbstract:The concentrations of 19 odorants, recently characterized by GC–olfactometry and aroma extract dilution analysis as the most odor-active compounds in raw Hazelnuts, were quantitated by stable isotope dilution assays (SIDA). Calculation of odor activity values (OAV) on the basis of odor thresholds in oil revealed high OAVs, in particular for linalool, 5-methyl-4-heptanone, 2-methoxy-3,5-dimethylpyrazine, and 4-methylphenol. A model mixture in sunflower oil containing the 13 odorants showing OAVs above 1 in their natural concentrations resulted in a good similarity compared to the overall nut-like, fruity aroma of the raw Hazelnuts. Quantitation of the 25 most odor-active compounds in roasted hazelnut paste by SIDA showed clear changes in the concentrations of most odorants, and formation of new odor-active compounds induced by the roasting process was observed. The highest OAVs were calculated for 3-methylbutanal (malty), 2,3-pentanedione (buttery), 2-acetyl-1-pyrroline (popcorn), and (Z)-2-nonenal (fatty)...
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changes in the key odorants of italian Hazelnuts coryllus avellana l var tonda romana induced by roasting
Journal of Agricultural and Food Chemistry, 2010Co-Authors: Andrea Burdackfreitag, Peter SchieberleAbstract:Application of a comparative aroma extract dilution analysis on aroma distillates isolated from either raw Italian Hazelnuts or a roasted hazelnut material produced thereof revealed 37 odor-active compounds in the raw nuts, whereas 46 aroma compounds were detected in the roasted nut material. 2-Methoxy-3-isopropylpyrazine and 2-methoxy-3,5-dimethylpyrazine as well as 5-methyl-4-heptanone predominated with the highest flavor dilution factors in the raw nuts, whereas 2-acetyl-1-pyrroline, 2-propionyl-1-pyrroline, 2-furfurylthiol, and 2-thenylthiol as well as (Z)-2-octenal, (Z)-2-nonenal, and (Z)-2-decenal showed the highest odor activities in the roasted nuts. These odorants, as well as several others, were previously unknown in Hazelnuts. In addition, the intensely seasoning-like smelling 3,5,5′-trimethyl-2(5H)-furanone was identified for the first time as a food aroma compound on the basis of a newly developed synthetic route and NMR measurements.
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development of a stable isotope dilution assay for the quantification of 5 methyl e 2 hepten 4 one application to hazelnut oils and Hazelnuts
Journal of Agricultural and Food Chemistry, 1999Co-Authors: P Pfnuer, Toshiro Matsui, Werner Grosch, Helmut Guth, T Hofmann, Peter SchieberleAbstract:A stable isotope dilution assay was developed for the quantitation of the hazelnut odorant 5-methyl-(E)-2-hepten-4-one by mass chromatography using synthesized [2H]2-5-methyl-(E)-2-hepten-4-one as the internal standard. Application of the method on two batches of commercial hazelnut oils, processed from either roasted or unroasted nuts, revealed 6.4 μg 5-methyl-(E)-2-hepten-4-one per kg of unroasted oil whereas 315.8 μg per kg was determined in the roasted nut oil. The about 50-fold higher amount of 5-methyl-(E)-2-hepten-4-one in roasted hazelnut oil suggested the necessity of a thermal treatment to generate the flavor compound. Pan frying of raw Hazelnuts (9 to 15 min) or boiling of the crushed nut material for 1 h in water led to an increase of 5-methyl-(E)-2-hepten-4-one by factors of 600 and 800, respectively, thereby corroborating that the major part of the nut flavorant is formed during heat treatment from a yet unknown precursor in Hazelnuts. Keywords: Stable isotope dilution assay; 5-methyl-(E)-2-...
Carsten Bindslevjensen - One of the best experts on this subject based on the ideXlab platform.
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roasted Hazelnuts allergenic activity evaluated by double blind placebo controlled food challenge
Allergy, 2003Co-Authors: Skamstrup K Hansen, Barbara Ballmerweber, Stefan Vieths, D Luttkopf, Per Stahl Skov, B Wuthrich, Carsten Bindslevjensen, Lars K PoulsenAbstract:Background: Allergy to Hazelnuts is a common example of birch pollen related food allergy. Symptoms upon ingestion are often confined to the mouth and throat, but severe systemic reactions have been described in some patients. The aim of the study was to evaluate the reduction in allergenicity by roasting of the nuts. Methods: Double-blind, placebo-controlled food challenges (DBPCFC) with roasted Hazelnuts (140°C, 40 min) were performed in 17 birch pollen allergic patients with DBPCFC-confirmed food allergy to raw Hazelnuts. The effect of roasting was further evaluated by skin prick test (SPT), histamine release (HR), measurement of specific IgE, and IgE-inhibition experiments. Results: In 5/17 patients the DBPCFC with the roasted nuts were positive. The symptoms were generally mild and included OAS (oral allergy syndrome) in all patients. Roasting of the nuts significantly reduced the allergenic activity evaluated by SPT, HR, specific IgE, and IgE-inhibition. Immunoblotting experiments with recombinant hazelnut allergens showed sensitization against Cor a 1.04 in 16/17 patients and against Cor a 2 in 7/17 patients. None of the patients were sensitized to Cor a 8. Challenge-positive patients did not differ from the rest in IgE-binding pattern. Conclusions: All the applied methods indicated that roasting of Hazelnuts reduces the allergenicity, but since 5/17 birch pollen allergic patients were DBPCFC-positive to the roasted nuts, ingestion of roasted Hazelnuts or products containing roasted Hazelnuts can not be considered safe for a number of hazelnut allergic consumers. For patients with a history of severe allergic symptoms upon ingestion of Hazelnuts, thorough and conscientious food labelling of Hazelnuts and hazelnut residues is essential.
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oral allergy syndrome the effect of astemizole
Allergy, 1991Co-Authors: Carsten Bindslevjensen, A Vibits, Stahl P Skov, B WeekeAbstract:: The effect of treatment with astemizole (Hismanal) on symptoms elicited by ingestion of Hazelnuts in birch pollen-allergic patients (the oral allergy syndrome) was investigated. Thirty patients with a well-documented allergy to silver birch, experiencing symptoms when ingesting Hazelnuts, were included in the study. All had a positive skin prick test (SPT) to birch, whereas 29 and 27, respectively, showed a positive RAST and basophil histamine release test (HR) to birch. In contrast, only 15 patients had a positive SPT to hazelnut, 13 had a positive RAST, whereas 24 had a positive HR. After two oral provocations with Hazelnuts the patients were randomized to receive either 10 mg of astemizole or placebo daily for 2 weeks in a double blind protocol followed by two oral provocations. Treatment with astemizole significantly reduced the symptoms compared with placebo (P = 0.004); however, without completely abolishing the symptoms.
