danharring54

December 22, 2023

Irritating odor from flowering Huisache tree

And some unusual early eluting Nitro- compounds

December 2, 2023

Paint thinner odor from Coconut ingredient - ketones

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Product label list of ingredients (precursors to off-odor compounds)

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How Hot It Was This Year in S.A. - Graphic Representation (2023)

Charts are put out by National Weather Service

Final 12-31-2023 (below)

October 8, 2023

Aliphatic aldehyde production in shortbread cookies (extended shelf life, without butter)

Shortbread cookies were sent in for testing. The opened, returned product had a foul pungent odor. The customer thought it was contaminated with some type of acid, and reported a burning sensation in the mouth and etching of the teeth. This was a product intended for an extended shelf life, and was vacuum packed. The ingredients did not include butter; instead the label (shown below) lists margarine (with partially hydrogenated soybean oil and liquid soybean oil).

Below: GC-MS peaks in normal cookies . Major peaks are heptadienal, the 2 decadienal isomers (normal breakdown products from linolenic acid with 2 double bonds), vanillin and ethyl vanillin (flavorings). The later peaks on the right starting around 30 minutes are the usual tocopherols, sterols and triterpenes (with no hydrocarbon waxes). The mass spectrum in the lower window is the ethyl vanillin peak (MW 166) at 19.2 minutes.

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Below: Peaks in the customer complaint sample:

The main peaks causing malodor in the bad sample were n-aldehydes from C4 to C11, and some unsaturated n-aldehydes up to C11:1. i.e. "C6 ALD" = hexanaldehyde, "C8 ALD" = octanal, etc.

Free fatty acids (FA) were the next biggest abnormal peaks; C6 (hexanoic acid at 11 minutes) was the most abundant of these. The longer chain C16 & C18 fatty acids are to be expected in all foods; shorter chain FAs are less common.

Others of note: 1-pentanol at 5.5 minutes, and 2-heptanone at 8.1 minutes. Up to 100 other peaks are present and were examined after zooming in, but the tentative IDs will not fit on the printout without cluttering things. Authentic reference standard solutions were available for n-alkanes, n-aldehydes, n-alkanoic acids, 1-alkanols, alkan-2-ones and some others. Standards for unsaturated and branched compounds were generally not available. Kovats retention indices on a DB5 column were consulted when available.

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Comparison overlay. Complaint sample Top, normal sample way down at the Bottom barely visible,

followed by 2 zoomed-in views to show how much bigger the peaks are in the complaint sample.

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Follow-up aging test a month later: looking for deteriorative changes in a normal cookie opened 1 month ago, compared to another normal cookie opened today.

There was no huge increase in breakdown products after 1 month. Things might be different for real shortbread cookies made with butter, rather than soybean oil based margarine. However, the soybean oil blend contained enough PUFAs to go very bad by 3 years in the bad sample.

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Comment, additional info:

There are so many chemically aggressive, noxious breakdown products here, it's not surprising it isn't immediately recognized as plain old rancidity, at a very advanced stage.

All of the cookies were over 3 years old (they were intended to have extended shelf-life; probably why they were made with margarine instead of butter).

The package of the returned complaint sample was examined, and found to have a single pinhole leak. This most certainly has a huge effect on lipid oxidation over an extended time. It could not be determined when and where the damage (or defect) occurred.

The analyst (TA) looked at a couple of the normal unopened cookies (3 years old); they had a tolerable aroma, taste and texture. TA washed away the after-taste with a Vitamin C containing juice (OJ, tomato).

Ingredient label showing oil source (precursor to the aldehydes):

October 5, 2023

Aliphatic aldehyde production in whole grain crackers

A box of whole grain crackers was sent in for testing. The product had a strong pungent odor. The customer complained of a petroleum taste and a burning sensation around mouth area. Another said it had a stale taste.

Ingredient list:

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GC-MS chromatogram overlay; Normal sample on bottom, complaint sample above it shows a huge increase in volatile breakdown products, mainly aliphatic aldehydes:

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ID of peaks in in bad sample; most are aldehydes up to C11 from fatty acid breakdown:

e.g. "C6 ALD" = hexanaldehyde; "C6 FA" = C6 (hexanoic) fatty acid

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Below are the n-aldehyde peaks and spectra in the sample extract, followed by n-aldehyde spectra at identical retention time from reference standard mix injection, and aldehyde reference spectra in NIST or Wiley library

Pentanal peak at 3.9 minutes:

Hexanal at 6.1 minutes:

Heptanal at 8.5 minutes:

Octanal at 10.8 minutes:

Nonanal at 12.9 minutes:

Decanal at 14.9 minutes:

Also, the earliest eluter butanal, at 2.5 minutes, on tail end of the solvent peak. The Inlet Purge Off time was shortened in order to see the very early eluters which usually wouldn't be seen by the time the solvent peak ends and the detector is turned on, These are not retained much by the 0.25 mm capillary column DB-5 phase, causing their peaks to co-elute and be very wide.