Application of targeted and non-targeted approaches to the determination of the key volatile and non-volatile components related to sensory attributesin glutathione-Maillard reaction products

Abstract

본 연구에서는 두 가지 다른 방법인 targeted와 non-targeted 기법을 이용하여 glutathione-Maillard 반응산물의 휘발성 및 비휘발성 성분을 규명하고자 하였다. 또한, 다변량통계분석기법 (multivariate statistical analysis)을 적용하여 관능적 특성인 쇠고기 향미에 관련된 휘발성 및 비휘발성 성분을 고찰하였다. Targeted 분석 기법에서는 향추출물희석분석법(aroma extraction dilution analysis)을 이용한 가스크로마토그래피-후각분석법 (gas chromatography-olfactometry)으로 glutathione-Maillard 반응산물의 향기활성성분(aroma-active compounds)을 규명하였다. 이러한 향추출물희석분석법을 통하여 glucose 또는 fructose와 반응시킨 glutathione-Maillard 반응산물에서 19개의 향기활성성분이 동정되었고, 이 중에서 황 함유 향기활성성분인 5-methylthiophene-2-carbaldehyde과 3-methylthiophene-2-carbaldehyde의 생성 경로를 설명하기 위해서 CAMOLA (carbohydrate module labeling) 기법이 이용되었다. 이러한 황 함유 화합물의 생성기작을 예측해 본 결과, 5-methylthiophene-2-carbaldehyde은 가열시 glutathione으로부터 분리된 hydrogen sulfide가 본래 6개의 탄소골격을 가진 glucose로부터 유래된 3-deoxyhexosone과 결합하는 것으로 나타났다. 또한, 3-methylthiophene-2-carbaldehyde의 생성기작은 glutathione으로부터 가열시 생성된 mercaptoacetaldehyde와 당으로부터 분리된 4개의 탄소골격을 가진 fragment와의 결합으로 이루어졌다. 한편, non-targeted 기법을 적용한 연구에서는, 가스크로마토그래피-질량분석법 (GC-TOF/MS)과 액체크로마토그래피-질량분석법 (UPLC-Q-TOF/MS) 등의 기기분석법과 관능검사를 통하여 glutathione-Maillard 반응산물의 향미 특성을 이해하고, 여기에 부분최소평방회귀분석 (partial least-squares regression)의 다변량통계방법을 적용함으로써 휘발성 및 비휘발성 성분과 관능적 특성과의 상관관계를 규명하였다. 2-methylfuran-3-thiol, 3-sulfanylpentan-2-one, furan-2-ylmethanethiol, 2-propylpyrazine, 1-furan-2-ylpropan-2-one, 1H-pyrrole, 2-(furan-2-ylmethyldisulfanylmethyl)furan, 2-methylthiophene 등의 향 성분들이 쇠고기 향미 특성에 주로 기여한 휘발성 화합물로 확인되었다. 또한, 비휘발성 화합물도 쇠고기 향미 특성에 기여하는 주요 성분으로 동정되었다.;In this study, two different approaches, targeted and non-targeted, were applied to investigate volatile and non-volatile components in glutathione-Maillard reaction products (GSH-MRPs). In targeted analysis, aroma-active compounds formed during the thermal reaction between GSH and reducing sugars were analyzed by gas chromatography-mass spectrometry (GC-MS) and GC-olfactometry (GC-O) with aroma extract dilution analysis (AEDA). Application of AEDA to GSH-MRPs led to the identification of 19 aroma-active compounds in the thermal reaction of GSH with glucose or fructose. In addition, the carbohydrate module labeling (CAMOLA) approach was also employed to elucidate the formation pathways for selected target sulfur aroma compounds, such as 5-methylthiophene-2-carbaldehyde, and 3-methylthiophene-2-carbaldehyde, which have not been reported previously. The intact carbon skeleton of glucose via 3-deoxyhexosone incorporated into 5-methylthiophene-2-carbaldehyde with the hydrogen sulfide of GSH. On the other hand, the formation of 3-methylthiophene-2-carbaldehyde may occur via the recombination of C-4 sugar fragment and mercaptoacetaldehyde. On the other hand, the non-targeted analysis was applied to investigate the relationship between chemical compositions and the sensory attributes of GSH-MRPs prepared under different reaction conditions using gas chromatography coupled with time-of-flight mass spectrometry (GC-TOF/MS) and ultra performance liquid chromatography-quadrupole-time-of-flight mass spectrometry (UPLC-Q-TOF/MS) combined with sensory analysis. Volatile and non-volatile components in GSH-MRPs correlating to the sensory attributes were determined using partial least-squares (PLS) regression. Volatile components such as 2-methylfuran-3-thiol, 3-sulfanylpentan-2-one, furan-2-ylmethanethiol, 2-propylpyrazine, 1-furan-2-ylpropan-2-one, 1H-pyrrole, 2-methylthiophene, and 2-(furan-2-ylmethyldisulfanylmethyl)furan could be identified as key contributors to the beef-related attributes of GSH-MRPs. Some non-volatile components were also determined as major components contributing to beef flavor. In this study, we demonstrated that the unbiased non-targeted analysis based on metabolomic approach allowed the determination of key volatile and non-volatile components related to beef flavor in GSH-MRPs.