향신료 중 주요 향기성분의 거울상이성질체 조성비 분석과 마이크로캡슐 제조에 관한 연구

Abstract

This study was performed to provide industrial application data of volatile flavor compounds from spices, the isolation and identification of volatile flavor compounds from spices, screening of chiral flavor compounds from identified volatile flavor compounds exhibited characteristic spice note, confirmation of an enantiomeric composition of chiral flavor compound by MDGC method, and microencapsulation of characteristic spice note, which is green note, by molecular inclusion and coacervation.

I. Analysis of volatile flavor compounds of spices

To extract the volatile flavor components in spice, simultaneous steam distillation & Extraction SDE) and solid phase microextraction SPME) methods were carried out and compared. In these results, the optimal extraction method and analysis condition were established. The volatile compounds of spices (dried garlic, ginger, red pepper and Chinese pepper) were extracted by simultaneous steam distillation and extraction (SDE) method and identified with gas chro- matography/mass spectrometer (GC/MS) analysis. A total of 48 compounds were identified in dried garlic and sulfur containing compounds were detected as the major compounds, and alcohols, aldehydes and esters were detected as minor compounds. Diallyl disulfide, diallyl trisulfide, 2-butyl-tetrahydrothiophene, allyl methyl disulfide, 2-allylthiopropionic acid, 3-vinyl-1,2-4H-dithiin, methyl propyl trisulfide were detected main components in dried garlic, and diallyl disulfide (38.80%), diallyl trisulfide (29.77%) were the major compounds. A total of 83 compounds were identified in dried ginger. α-Zingiberene (29.82%) and β-sesquiphellandrene (10.77%) were the major compounds and geranial, (Z,E)-α-farnesene, β-phellandene, β-bisabolene and camphene were detected as considerable amounts. A total of 71 compounds were identified in dried red pepper, and the major compounds were 2-methyl propanal, furfural, benzaldehyde, nerolidol, 4-hydroxy-β-ionone up to 4%. α-Cedrol, linalool, 3-methyl butanal were also detected. A total of 60 compounds were identified and quantified in dried Chinese pepper, and the major compounds were identified estragole, nonanoic acid, octanoic acid, octanal, hexanal, (E)-2- undecenal and sabinene. Among them, estragole (47.47%) was found as the predominantly abundant component of dreid Chinese pepper.

II. Analysis of chiral flavor compounds of spices

To evaluate enantiodifferentiation of chiral compounds in the previous analysis of volatile flavor components in spices, selected chiral compounds in volatile flavor constituents of dried garlic, ginger, red pepper and Chinese pepper were characterized by multidimensional gas chromato graphy/mass spectrometry (MDGC/MS). Selected chiral compound in dried garlic was 2-propanol and that was detected by high enantiomeric purity (>99%) for (R)-enantiomer. α-Pinene and nerolidol in dried ginger were detected by high enantiomeric purity (>96%) for (S)-form, and β-pinene was detected only (R)-form. The enantiomeric composition of α-terpineol in dried ginger revealed 72.0% for (R)-form, and linalool and 4-terpineol showed mixtures of both enantiomers. (S)-Enantiomer was the major enantiomer of limonene in dried ginger having enatiomeric excess of 17.2%. Linalool in dried red pepper were determined mixtures of both enantiomer and nerolidol was detected only (S)-form. α-Pinene and nerolidol, and β-pinene and linalool which are chiral compounds in Chinese pepper were determined to be enantiomerically pure (>99%) for their (S)-form and (R)-form, respectively. The enantiomeric composition of limonene in Chinese pepper revealed 83.9% purity for the (S)-enantiomer, whereas (E)- and (Z)-rose oxides showed mixtures of both enantiomers. The enantiomeric excess (%) for citronellal was 22.6% with the (R)-enantiomer as major enantiomer. The enantiomeric composition of these compounds can be used as parameter for authenticity control of dried garlic, ginger, red pepper, and Chinese pepper.

III. Study on the Microencapsulation of Green note in Spices

Microcapsules of green note such as β-ionone, (Z)-3-hexenol, (E,Z)-2,6- nonadienal in spices were prepared by molecular inclusion and complex coacervation. β-Ionone was complexed with α-cyclodextrin (αCD) and β-cyclodextrin (βCD) in the mole ratio 1:1 and 1:2 host:guest, and the complexes formed by co-precipitation were analyzed by FT-IR, SEM, DSC and TGA. Percent β-ionone included in the complex was also determined by hexane extraction and GC-MS analysis. The best condition of complex formation was 1:1 mole ratio of β-ionone:βCD. In this condition, flavor/CD complex prepared with (Z)-3-hexenol and (E,Z)-2,6-nonadienal and the release characteristics of flavoring materials in complex were evaluated. The release rate of flavor was considerably faster than those of encapsulated flavor. (Z)-3-Hexenol/CD complex were stable at 60℃ for 14 days. Flavor microcapsules were prepared by complex coacervation between gelatin and arabic gum. Microcapsules were characterized by FT-IR, particle analyzer, optical microscopy, DSC and TGA according to hardening agent volume, emulsifier, stirring speed and core material amounts. It was found that addition of emulsifier result in threefold smaller microcapsule size. When the stirring speed and amounts of core material increased, the particle mean diameter was increased. Thermal profile of microcapsules by DSC and TGA analysis were stable under 80℃. Consequently, microencapsulation possibility of green note by molecular inculsion and compolex coacervation were confirmed.