Is it safe to have ammonia in the home? Won’t it turn all your starched linen yellow via a Rogers’ Maillard reaction?

 

 

Late addition (July 2019)

Please forgive this postscript, correction, “prescript”,  correction, intrusion, added many years later – based on some 350 and more postings here and elsewhere.

That’s including some 7 years of my hands-on investigation into image-forming techniques, chosen to be credible with simple, indeed crude, medieval (14th century) technology etc etc.

(Oh, and yes, I accept the radiocarbon dating, despite it being restricted to a single non-random corner sample, making all the oh-so-dismissive, oh-so-derogatory statistics-based sniping totally irrelevant – a ranging shot being just that me dears- a single ranging shot, albeit subdivided into three for Arizona, Oxford and Zurich).
Sindonology (i.e. the “science” , read pseudoscience – of the so-called “Shroud ” of Turin) can be simply summed up. It’s a re-branding exercise, one designed to pretend that the prized Turin possession is not just J of A’s “fine linen”, described in the biblical account as used to transport a crucified body from cross to tomb.

Oh no, it goes further, much further, way way beyond the biblical account. How? By making out that it was the SAME linen as that described in the Gospel of John, deployed as final “burial clothes”. Thus the description “Shroud” for the Turin Linen, usually with the addition “burial shroud”. Why the elision of two different linens, deployed for entirely different purposes (transport first, then final interment)? 
Go figure! Key words to consider are: authentic relic v manufactured medieval icon; mystique, peaceful death-repose, unlimited opportunity for proposing new and ever more improbable image-formation mechanisms etc. How much easier it is to attach the label “Holy” to Shroud if seen as final burial clothes, in final at-peace repose – prior to Resurrection- as distinct from a means of temporary swaying side-to-side transport in an improvised makeshift stretcher !
As I say, a rebranding exercise (transport to final burial shroud) and a very smart and subtle one at that . Not for nothing did that angry local Bishop of Troyes suddenly refer to a “sleight of hand” after allegedly accepting it when first displayed. Seems the script was altered, or as some might say, tampered with! It might also explain why there were two Lirey badges, not just one. Entire books could be written on which of the two came first… I think I know which, with its allusion (?) to the Veil of Veronica… yes, there are alternative views (the face above “SUAIRE” a visual link to the face-only display of the Linen as the “Image of Edessa” or as that on the then current “Shroud” per se.

https://shroudofturinwithoutallthehype.wordpress.com/2014/02/17/am-i-the-only-one-to-have-spotted-that-the-lirey-shroud-was-piggybacked-on-the-veil-of-veronica-which-probably-explains-why-the-french-still-call-it-the-suaire-sweat-impregnated-facecloth-de-t/

 

Face shown  (left) on mid- 14th century Machy Mould (recently discovered variant of the Lirey Pilgrim Badge) above the word “SUAIRE” (allegedly meaning “shroud”). Inset image on the right: one version among many of the fabled “Veil of Veronica” image.  I say the two are related, and deliberately so, but this is not the time or place to go into detail.

No, NOT  a resurrectional selfie, but instead a full size version of, wait for it,  the legendary VEIL OF VERONICA , product of inital body contact – no air gaps- between body and fabric, but with one important difference. The Turin image was intended to look more realistic, less artistic.

How? By displaying a negative tone-reversed image implying IMPRINT (unless, that is, you’re a modern day sindonologist, in which case ‘resurrectional proto-photographic selfie” becomes the preferred, nay, vigorously proferred explanation assisted by unrestrained imagination, creation of endless pseudoscience etc etc, with resort to laser beams, corona discharges, nuclear physics, elementary particles, earthquakes etc etc – the list is seemingly endless! 
Welcome to modern day sindonology. 
Personally, I prefer no-nonsense feet-on-the-ground hypothesis-testing science, aided by lashings of, wait for it, plain down-to-earth common sense.

Start of original posting:

 

 

In the days before detergents and detergent-containing cleaning aids, there would be a bottle of ammonia solution under the sink.

It was some years before I learned how it worked as a cleaning agent (it’s apparently/allegedly to do with creating alkaline conditions that turn fat and oil into soap – it’s a ‘saponifying agent’).  Do you really think it would have been used if exposure to ammonia fumes caused latent yellow coloration of fabrics etc?

Just think: starch used to be used for shirt collars etc, indeed entire items like table napkins? What would the man of the house have said if his collars turned yellow because missus had been using ammonia at the sink?

If ammonia reacted appreciably with starch or other linen constituents to make white go yellow -or  worse still brown-  methinks our parents and grandparents would have quickly cottoned on – no pun intended –  and the domestic market for ammonia would have fallen flat on its face.

The thing that protects reducing sugars – whether from broken down starch or other sources – is the relatively high temperature needed to get a Maillard reaction going – at least 50 degrees C, but preferably higher – much higher.  Superheated steam is used to make the brown coloring agent in Coke  from corn sugar and ammonia – a typical Maillard product: typical room temperature, or even the heat of the kitchen, is/was simply not high enough to produce visible amounts of those yellow polymeric substances that we lump together with toasted food under the heading of ‘Maillard reaction products’.

Rogers’ Maillard hypothesis was based on a fantasy  – allied with wishful thinking – namely that a particular length of fabric was impregnated and indeed a rich source of reducing sugars, and that the latter are an easy target for gaseous amines.

For a thermochemist to have proposed that  a Maillard reaction could produce an iconic image at environmental temperatures, without an obvious source of heat ( except a brief hypothesised spell of post-mortem thermogenesis to 42 degrees max)  was remarkable to say the least. Maybe he was too focused on finding chemistry that would provide a ‘low-temperature’ scorch-like image – to avoid having to think about high-temperature scorches that did not fit with the scenario of a 1st century tomb.  High-temperature scorching  can  be easily accommodated, needless to say,  into a medieval narrative – with or without intentional forgery as the first step-  the Mark 1 image, ‘negative’ and seemingly ‘branded-on’,  being simply that of a naked un-Christ-like unbloodied man – like the one on the Lirey Pilgrim’s badge (you know, that artefact marking the first recorded display of the Shroud in western Europe, circa 1355 the one that Shroudologists studiously ignore for the most part, much preferring to play “hunt the Mandylion“).

Lirey Pilgrim’s Badge,circa 1355, Cluny Museum, Paris. Note the herringbone weave – a vital clue – one of severa l- to authenticity re depicting the then Lirey (now Turin) Shroud.

PS: this comment (click on hash 10 below) has just appeared from Jos Verhulst on The Other Site:

August 13, 2012 at 2:50 am | #10

“Again, it should be noted that the gist of the argument offered by Colin Berry is this one:

“However, one can always fall back on first principles, and write the Rogers reaction as follows:

Putrefaction amines (gases) + reducing sugars from starch etc (solid) —-> Maillard reaction products (solid)

Straightaway one sees that the entropy change is in principle unfavourable, since it involves a disordered gas reacting to form a more ordered solid.”

This seems to be wrong, as far as I can see, because there will be small gaseous products that should appear on the right side of this reaction scheme.”

Not in the initial step, Jos, which we know from the early model studies of Lea and Hannan (1949)almost certainly has a very high Q10 (see yesterday’s post) which means it  – the reaction between gaseous amine and reducing sugar – is exceedingly reluctant to ‘go’ in the normal range of environmental temperatures, say 0 degrees to 40 degrees C (as might have existed in a 1st century tomb).

The splitting off of small molecules comes later in the dehydration, condensation and maybe final polymerisation reactions to produce the yellow or brown colour, but if the first step in the reaction is hindered for any reason, kinetic or thermodynamic- there is nothing to feed into that long, complex sequence of steps we call a Maillard reaction.

(Did you see the post I addressed to you earlier?  Perhaps not, since Dan Porter deleted the link I placed on his site, which according to him was ‘bad netiquette’.  How bizarre that someone who shamelessly pirates my copy, sometimes most if not all of it including images, usually within an hour or two, even minutes of me posting it here on MY blog, should be lecturing me on ‘netiquette’).

PS:  I have just been refreshing my memory on Schiff base formation, often described as the first step in the Maillard reaction between an amine and a reducing sugar. In fact it is two steps, the first to form a hemiaminal by nucleophilic addition,  which then dehydrates in the second step to form the imine with loss of a molecule of water.  So there’s a sense in which we are both right – it either does or does not involve splitting off of water, depending on whether you consider both steps, or just  the first addition step in isolation. If you are measuring loss of amino nitrogen (see Lea and Hannan) as distinct from Schiff base formation, then the first addition step alone is presumably sufficient to record loss of the -NH2 functional group.

Afterthought:  Tuesday 14 Aug   Even if the “first”step is deemed to involve loss of a small molecule, and declared to be thermodynamically more feasible (more arrangements, more randomness, more entropy) it overlooks a certain factor. Water at normal temperature and pressure is an unusually ordered liquid, due to extensive intermolecular hydrogen bonding. The thermodynamic dividend from splitting off water might not be realized unless or until the water were in the vapour state. I do wonder in fact, looking at Lea and Hannan’s relative humidity data, if evaporation of water is not a key thermodynamic driving force in the early stages involving one or more dehydration reactions – contributing to the enormous effect of temperature on reaction rates in the environmental range of temperature. Could rates of dehydration of intermediates be the rate-limiting factor?

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About Colin Berry

Retired science bod, previous research interests: phototherapy of neonatal jaundice, membrane influences on microsomal UDP-glucuronyltransferase, defective bilirubin and xenobiotic conjugation and hepatic excretion, dietary fibre and resistant starch.
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