The Chemical Components of Onion Vapors Responsible for Wound-healing Qualities

Fresh juice of Cecile cultivar cabbage (Brassica oleracea) was inhibitory to the growth of four species (including seven strains) of lactic acid bacteria. Inhibition was eliminated when the cabbage was heated (steamed 10 min) before juice extraction. When Lcuconostoc mesenter-odes C33 was tested in juices of three other cultivars of cabbage, growth inhibition was invariably noted in fresh juices, but was variable in heated juices. Fresh cabbage juice (U) adjusted to higher initial pH (6.5-7.5) showed greater antibacterial activities than at pH 5.0 to 6.0. When pH 4.0 precipitate from fresh CJ was added to noninhibitory CJ (cabbage heated before extraction), antibacterial activity was restored. A heat-labile and pH-dependent factor seemed responsible for activating a precursor into an inhibitory compound.

Section: Methodssupporting

confidence: 89%

Antibacterial Activity of Cabbage Juice Against Lactic Acid Bacteria

Kyung

Fleming

1994

“…Fresh, uninoculated sterile garlic extract became milky in appearance upon standing, and a precipitate began to appear 6-12 hr after preparation. A similar observation was made with onion distillate (Kohman, 1947) and fresh cabbage juice (Kyung and Fleming, 1994).…”

Section: Preparation Of Garlic Extractsupporting

confidence: 77%

Isolation and Characterization of Bacteria Resistant to the Antimicrobial Activity of Garlic

Kyung

Park

Kim

1996

Twenty-six bacteria were isolated from garlic (Allium sativum) and characterized. They all were identified as Leuconostoc mesenteroides subsp. mesenteroides. All the isolates were resistant to antimicrobial activity of garlic and grew or survived in TSB with 10% garlic extract while other bacteria and yeasts from our laboratory collection were killed when 1-2% garlic extract was in the culture media. Garlic isolates were also more tolerant than common laboratory strains to the toxic effect of methyl methanethiosulfonate, a thiol inhibitor similar to allicin. This is the first report of the isolation of naturally occurring bacteria resistant to antimicrobial activity of garlic.

“…Kohman (6) suggested that the lachrymatory principle of the onion was due to a thiolaldehyde. There was no evidence from any data obtained in this investigation that either thiopropionaldehyde or thioallylaldehyde was collected in any of the traps.…”

Section: Resultsmentioning

confidence: 99%

“…On the basis of the quantity of sulphur, allyl propyl disulfide was calculated. I n an earlier paper Kohman (6) attributed the lachrymating properties of the onion to a thioaldehyde (thiopropionaldehyde or thioallylaldehyde) which he determined by the expedient of distilling the onion in vacuo a t 50" C., oxidizing a weighed sample of the distillate residue with bromine and determining the sulphur present. The amount of sulphur was equivalent to that in the thioaldehyde which he hypothesized on the basis of the various observations made.…”

mentioning

confidence: 99%

The Onion: Gaseous Emanation Products

Niegisch

Stahl

1956

The problem of tracing normal food odors and off-odors to their source must ultimately be solved by actual identification and isolation of chemical components for individual study. To quote Turk (11): "Much of our present information on constituents of common odors is purely nominal and based on old and uncomplete research." Such is the case for the onion.Thus Semmler (9), in 1892, claimed to have obtained a sulfide of unknown constitution from the oniog, of the same molecular formula, but different boiling point than the allyl propyl disulfide which he reports in garlic oil. Kohman, (7') quoting Semmler as identifying allyl propyl disulfide as the onion flavor, measured this quantitatively by oxidizing the product of steam distillation with bromine to the sulfate state and determining sulphur gravimetrically. On the basis of the quantity of sulphur, allyl propyl disulfide was calculated. I n an earlier paper Kohman (6) attributed the lachrymating properties of the onion to a thioaldehyde (thiopropionaldehyde or thioallylaldehyde) which he determined by the expedient of distilling the onion in vacuo a t 50" C., oxidizing a weighed sample of the distillate residue with bromine and determining the sulphur present. The amount of sulphur was equivalent to that in the thioaldehyde which he hypothesized on the basis of the various observations made. Propionaldehyde was also identified by isolation and formation of its dinitrophenylhydrazone. Challenger and Greenwood ( 2 ) then detected n-propylthiol by absorption of the thiol in mercuric cyanide. They were not able to determine whether it occurs in the undamaged bulb or whether it is liberated by enzyme action after slicing.Since little positive information has been published concerning the volatile constituents of onions, it was decided to apply the methods of instrumental analysis with the intention of outlining a technique which may be applicable to most other food odor problems. The following work is a report on a mass spectrometric and infrared spectroscopic analysis of vapors trapped at various low temperatures in the absence of air. EXPERIMENTAL PROCEDUREA model 21-103B Consolidated analytical mass spectrometer and a Baird infrared spectrometer were used in the present work. Volatile constituents of onions were collected by trapping the vapors at -30", -go", and -190" C. in a system as shown in Figure 1. The contents of the traps were individually analyzed mass spectrometrically, and then condensed into the distillation tube, or examined by gas partition chromatography (GPC). The distillation technique yielded between 3 to 5 cuts from the contents of each trap. A trapping system made possible the collection of gases separated by GPC. " Presently with the Bakelite Research Center, Bloomfield, New Jersey. 657 658 W. D. NIEGTSCH A N D W. H. STAHL ii U n -19o.c. iil in -0D.C W -30.C Figure 1. High vacuum trapping system and low temperature-low pressure distillation tube for pref ractionation.Preparation of system. Approximately 100 to 140 g. of onion are frozen in l...