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Tadashi Yoshihashi – One of the best experts on this subject based on the ideXlab platform.
Sensory test for aroma and quantitative analysis of 2-Acetyl-1-Pyrroline in Asian aromatic rice varieties.Plant Production Science, 2006Co-Authors: Nguyen Loc Hien, Tadashi Yoshihashi, Wakil Ahmad Sarhadi, Yutaka HirataAbstract:
(2006). Sensory Test for Aroma and Quantitative Analysis of 2-Acetyl-1-Pyrroline in Asian Aromatic Rice Varieties. Plant Production Science: Vol. 9, No. 3, pp. 294-297.
Effect of Storage Conditions on 2–Acetyl-1–pyrroline Content in Aromatic Rice Variety, Khao Dawk Mali 105Journal of Food Science, 2005Co-Authors: Tadashi Yoshihashi, Nguyen Thi Thu Huong, Vipa Surojanametakul, Patcharee Tungtrakul, Warunee VaranyanondAbstract:
ABSTRACT: The effect of package and temperature on 2–acetyl-1–pyrroline content in milled aromatic rice during storage was investigated. 2 -Acetyl-1 -pyrroline content was decreased faster at higher storage temperature. However, fat acidity of rice was increased during storage and inversely correlated with 2–acetyl-1–pyrroline content at an early stage of storage. The difference in 2–acetyl-1 -pyrroline recovery from the samples, which were extracted with ethanol at 40 °C and 75 °C, revealed that the starch bound and free forms of 2–acetyl-1–pyrroline may occur in aromatic rice. These results suggested that the biosynthesis of 2–acetyl-1 -pyrroline before starch structure formation in rice kernel could play a key role in the aroma quality of aromatic rice.
Area Dependency of 2-Acetyl-1-Pyrroline Content in an Aromatic Rice Variety, Khao Dawk Mali 105Japan Agricultural Research Quarterly: JARQ, 2004Co-Authors: Tadashi Yoshihashi, Thi Thu Huong Nguyen, Nobuyuki KabakiAbstract:
It has been stated that the quality of the aromatic rice variety, Khao Dawk Mali 105 is influenced by the environment of the production area or cultivation method. In this study, 2-Acetyl-1-Pyrroline content of various rice samples in Thailand was investigated. The results showed that the samples from the Northeastern region, where Khao Dawk Mali 105 was cropped in rain-fed paddy fields, were higher in 2-Acetyl-1-Pyrroline content. The “Tungkularonghai” area, stated as being the highest quality rice production area, had the highest content among the areas in Northeastern Thailand. Samples collected from non-drought condition areas showed lower content even in the Tungkularonghai area. However, differences in seeding method did not affect 2-Acetyl-1-Pyrroline content in the Tungkularonghai area. These results showed that dry climate might be a factor for 2-Acetyl-1-Pyrroline content in Khao Dawk Mali 105. Since Khao Dawk Mali 105 is a photosensitive variety, it was expected that the ripening stage becomes uniform at a certain period which should be suitable for 2-Acetyl-1-Pyrroline formation in paddy fields.
Peter Schieberle – One of the best experts on this subject based on the ideXlab platform.
Mechanistic Studies on the Formation of the Cracker-like Aroma Compounds 2-Acetyltetrahydropyridine and 2-Acetyl-1-Pyrroline by Maillard-type ReactionsThe Maillard Reaction in Foods and Medicine, 2005Co-Authors: Peter Schieberle, Thomas HofmannAbstract:
1-Pyrroline, the Strecker degradation product of the amino acids proline or ornithine, was identified as the key intermediate in the formation of the intense roast-smelling food odorants 2-acetyltetrahydropyridine (ATHP) and 2-Acetyl-1-Pyrroline (AP). Reacting 1-pyrroline with hydroxy-2-propanone yielded high amounts of only the ATHP, whereas the reaction with 2-oxopropanal gave only AP. Synthesized 2-(1-hydroxy-2-oxo-1-propyl)-pyrrolidine was shown to be the key precursor of ATHP. The last step in AP formation was shown to be simply an air oxidation of 2-acetylpyrrolidine, which is proposed to be formed from 1-pyrroline and 2-oxopropanal via the intermediate 2-(1,2-dioxo-1-propyl) pyrrolidine.
studies on the key odorants formed by roasting of wild mango seeds irvingia gabonensisJournal of Agricultural and Food Chemistry, 2000Co-Authors: A O Tairu, T. Hofmann, Peter SchieberleAbstract:
Application of the aroma extract dilution analysis on a concentrate of volatiles obtained by solvent extraction and high vacuum distillation from roasted seeds (180 °C; 15 min) of wild mango (Irvingia gabonensis) revealed 32 odor-active compounds with flavor dilution (FD) factors ranging from 8 (low odor activity) to 2048 (high odor activity). The identification experiments based on the use of reference odorants revealed methional (cooked potato-like) followed by 2-Acetyl-1-Pyrroline (roasty, popcorn-like), butan-2,3-dione, pentan-2,3-dione, 2-ethyl-3,5-dimethylpyrazine, and 2,3-diethyl-5-methylpyrazine as the key aroma compounds among the 27 odorants identified. All odorants are reported for the first time as components of roasted wild mango seeds. Keywords: Wild mango; Irvingia gabonensis; aroma extract dilution analysis; methional; 2-Acetyl-1-Pyrroline
New and Convenient Syntheses of the Important Roasty, Popcorn-like Smelling Food Aroma Compounds 2-Acetyl-1-Pyrroline and 2-Acetyltetrahydropyridine from Their Corresponding Cyclic α-Amino AcidsJournal of agricultural and food chemistry, 1998Co-Authors: Thomas Hofmann, Peter SchieberleAbstract:
Novel straightforward syntheses have been developed supplying the important food odorants 2-Acetyl-1-Pyrroline (AP) and 2-acetyltetrahydropyridine (ATHP) in high yields. The four-step reaction sequence starts from the N-shielded cyclic alpha-amino acids L-proline and pipecolinic acid, respectively, which, in the first step, are converted into the N-shielded 2-acetyl derivatives. Removing the shielding group with trifluoroacetic acid afforded the 2-acetylpyrrolidine and 2-acetylpiperidine trifluoroacetate, respectively, which, upon increasing the pH of their aqueous solutions to 7.0, are spontaneously oxidized in high yields into AP (43% based on L-proline) or ATHP (35% based on pipecolinic acid), respectively, by air oxygen. The latter step is an important hint at the last step in the yet unclear formation pathways of both odorants in foodstuffs.
Keith R. Cadwallader – One of the best experts on this subject based on the ideXlab platform.
Spray-chilling encapsulation of 2-Acetyl-1-Pyrroline zinc chloride using hydrophobic materials: Storage stability and flavor application in food.Food chemistry, 2018Co-Authors: Yun Yin, Keith R. CadwalladerAbstract:
Abstract 2-Acetyl-1-Pyrroline (2AP) is a popular yet highly unstable aroma compound, which limits its commercial use as a flavoring ingredient. The stability and application of spray-chilled paraffin-coated microcapsules of 2AP zinc chloride complex (2AP–ZnCl2) were investigated in this study. 2AP–ZnCl2 microcapsules (0.081% (w/w) 2AP loading) and unprotected 2AP–ZnCl2 complex were subjected to ambient storage at four different relative humidities (RH; ∼0%, ∼22.5%, ∼43.2% and ∼100%). The results showed that the microcapsules had significantly greater 2AP stability compared with the unprotected complex under all storage conditions studied. A flavor application study using instant rice was also performed to validate the potential effectiveness of using 2AP–ZnCl2 microcapsules as a flavoring agent. Full 2AP recovery was achieved after the cooking process, where the controlled release function of the microcapsules was clearly exhibited. The results demonstrated that microencapsulation of 2AP–ZnCl2 allows for more flexible handling/storage practices and has potential for application by the flavor industry.
Starch-Flavor Complexation Applied to 2-Acetyl-1-Pyrroline.Journal of agricultural and food chemistry, 2018Co-Authors: Bethany J. Hausch, Jeanette A. Little, James A. Kenar, Keith R. CadwalladerAbstract:
The pleasant popcorn-like smelling compound 2-Acetyl-1-Pyrroline (2AP) occurs naturally in many foods but is scarcely used as a flavoring agent due to its great instability. In this work, we evaluate the potential of high amylose corn starch to complex and stabilize 2AP. The methodology was first optimized using model compounds, 2-acetylpyridine and 2-acetyl-2-thiazoline, and then applied to 2AP. Complexes were successfully prepared and characterized using X-ray diffraction, gas chromatography, and differential scanning calorimetry. Loadings of up to 0.504 (±0.071)% 2AP were achieved, and storage studies showed that over half of the flavor was retained after 2 weeks at 0% relative humidity. To our knowledge, this is the first demonstration that 2AP can form amylose inclusion complexes and may lead to a method to effectively stabilize this labile aroma compound.
Spray-chilling encapsulation of 2-Acetyl-1-Pyrroline zinc chloride complex using hydrophobic materials: Feasibility and characterization of microcapsulesFood chemistry, 2018Co-Authors: Yun Yin, Keith R. CadwalladerAbstract:
A moisture-sensitive 2-Acetyl-1-Pyrroline zinc chloride complex (2AP-ZnCl2) was successfully encapsulated by spray-chilling, using a hydrophobic moisture barrier as a practical way to protect the complex and to help facilitate its general use in food applications. Use of octacosane as wall material provided a flavor retention of 65.3%. The results from scanning electron microscopy (SEM) and X-ray micro-computed tomography (X-ray micro-CT) indicated desirable morphological characteristics of the matrix type microcapsules. Gas chromatography (GC) and absorbance spectroscopy were used for chemical quantitation of 2AP and ZnCl2, respectively, in the microcapsules. Results revealed no degradation of 2AP occurred as a result of the encapsulation process. This study is the first to demonstrate the feasibility of producing high quality microcapsules from labile flavor complexes by spray-chilling. The use of generally recognized as safe (GRAS) substances, including 2AP and ZnCl2, may allow for widespread commercial use of 2AP as a flavor ingredient.