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Chemical analysis and origin of geosmin, an major flavor component of red beets (Beta vulgaris L.).

机译:红甜菜(Beta vulgaris L.)的主要风味成分土臭素的化学分析和来源。

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摘要

Geosmin is a major flavor compound found in red beets (Beta vulgaris L.) and imparts an ‘earthy’ sensory characteristic to this vegetable. To date, it is not known whether geosmin is a by-product of beet metabolism or is absorbed by the beet root once the flavor compound is synthesized by soil-borne microorganisms. Research with geosmin is complicated by the fact that most analytical methods require large sample sizes (≥1 kg) and are time-consuming to perform. Thus, the objectives of this study were to (a) develop a simplified method for the analysis of geosmin, (b) determine origins of the flavor compound, and (c) identify other volatile compounds in mature red beet roots. Geosmin was analyzed by headspace solid phase microextraction (HSPME) using a polydimethyl-siloxane/divinylbenzene fiber with (−)-menthone serving as the internal standard. The extraction commenced at 60°C for 2 hr after which the volatile compounds were desorbed and analyzed by gas chromatography. The detection limit of geosmin using HSPME was approximately 1 μg/kg while relative recoveries ranged from 99.2 ± 7.4% for roots to 72.0 ± 4.2% for seedlings. Geosmin was detected in red beet seedlings grown under aseptic conditions in a synthetic growth medium. When geosmin was added to the medium, the seedlings did not absorb the flavor compound. These studies indicate that red beets are capable of endogenous synthesis of geosmin. Besides geosmin, red beet roots contained a number of volatile compounds including 2-methoxy-3-(1-methylethyl)pyrazine, methanethiol, several medium-chain aldehydes (C7, C8, C9, and C10), 2-methylpropanal, benzeneacetaldehyde and others.
机译:Geosmin是红甜菜( Beta vulgaris L.)中发现的主要风味化合物,并赋予这种蔬菜以“土”感。迄今为止,还不知道一旦土壤中的微生物合成了风味化合物,土臭素是甜菜代谢的副产品还是被甜菜根吸收。由于大多数分析方法都需要大样本量(≥1 kg),并且执行起来很费时间,因此使用土臭素的研究非常复杂。因此,本研究的目的是(a)开发一种简化的方法来分析土臭素,(b)确定风味化合物的来源,以及(c)鉴定成熟红甜菜根中的其他挥发性化合物。通过使用(-)-薄荷酮作为内标的聚二甲基硅氧烷/二乙烯基苯纤维,通过顶空固相微萃取(HSPME)分析土臭素。在60℃下开始萃取2小时,然后将挥发性化合物解吸并通过气相色谱法分析。使用HSPME检出的土臭素的检出限约为1μg/ kg,相对回收率从根的99.2±7.4%到幼苗的72.0±4.2%不等。在合成条件下,在无菌条件下生长的红甜菜幼苗中检测到土臭素。当将土臭素添加到培养基中时,幼苗没有吸收风味化合物。这些研究表明,红色甜菜能够内源性合成土臭素。除土臭素外,红甜菜根还含有许多挥发性化合物,包括2-甲氧基-3-(1-甲基乙基)吡嗪,甲硫醇,几种中链醛(C 7 ,C 8 < / sub>,C 9 和C 10 ),2-甲基丙醛,苯乙醛等。

著录项

  • 作者

    Lu, Guiping.;

  • 作者单位

    Washington State University.;

  • 授予单位 Washington State University.;
  • 学科 Agriculture Food Science and Technology.; Chemistry Analytical.
  • 学位 Ph.D.
  • 年度 2002
  • 页码 76 p.
  • 总页数 76
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 农产品收获、加工及贮藏;化学;
  • 关键词

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