Posts Tagged ‘Maillard Reaction’

Colin Berry On Rogers and Arnoldi Paper

May 24, 2015 12 comments

imageYesterday, Colin Berry, in one of his updates to his seemingly always evolving and meandering long postings, tells us what he would have done had he been refereeing Rogers’ and Arnoldi’s paper, “THE SHROUD OF TURIN: AN AMINO-CARBONYL REACTION (MAILLARD REACTION) MAY EXPLAIN THE IMAGE FORMATION”, which appeared in the peer-reviewed journal Melanoidins:

Had the paper come to me for refereeing… it would have been rejected out of hand.

I’d have appended the following specific comments to the author and journal Editor:

1. Do not go citing Pliny the Elder out of the blue, begging the question re Shroud authenticity, implying that the radiocarbon dating can be safely ignored.  Oh no it cannot. The author might think it invalid, based on his examination of a few threads illicitly removed from the radiocarbon sample, with a subsequent gap in the chain of custody. But he cannot expect others to take his rejection as the consensus position in science. It’s not. Indeed, the manner in which Pliny has been insinuated into the above text suggests strongly that Raymond N.Rogers was not strictly neutral and disinterested on the subject of authenticity when he penned the above paper, making it worryingly possible that he was not  neutral at the time he worked with STURP in 1978. It’s my belief that Rogers was a closet authenticist. If he considered the radiocarbon dating, then he as STURP’s chemical team leader should have been the one to press for a repeat dating – not to go tacitly assuming authenticity. Science has to be totally objective in its written PEER-REVIEWED publications.

2.The presence of starch "confirmed" with a reagent that designed to test for something entirely different? The correct reagent for detecting starch is a solution of iodine in potassium iodide, which gives a blue-black inky colour with starch. A solution of iodine in sodium azide, intended to detect sulphoproteins, one that gives a totally different colour (red), CANNOT be assumed to be testing for starch UNLESS VALIDATING TESTS ARE REPORTED.  They were not. We are asked to accept that iodine/azide is a dual purpose reagent. Who says? Neither does it inspire confidence to see a reference to "amilose", it being AMYLOSE needless to say. Secondly the differentiation between amylose (straight chain starch) and the unmentioned amylopectin (branched chain starch) simply cannot be inserted into a scientific account without a word of explanation. In nay case, the two components of starch were not properly recognized as distinct chemical entities until the 1940s. Their relevance to colorimetric tests for starch is highly questionable to say the least, unless dealing with genetic variants of wheat that are enriched in one or the other (e.g. waxy maize starches that are almost entirely amylopectin, which gives a red or purple colour with iodine/potassium iodide). What we see here is at best sloppy and imprecise unscientific reporting that should never have got past the referees.

3. There is no conclusive evidence that starch or other polysaccharides and/or sugars are  present on the Shroud, and even if the red colour with iodine/azide were admissible evidence, for which no assurance is offered, the evidence for that was from Adler and Heller. One CANNOT GO BASING MAJOR CLAIMS (as Roger’s "starch fraction/Maillard hypothesis" has become a major claim) on evidence from other workers, in other laboratories, that is little more than anecdotal.


Those Dark Specks in the Mark Evan’s Photographs

October 31, 2014 33 comments

that unforgivable hoovering

Colin Berry, with his non-stop observant and inquisitive mind:

Am I not correct in thinking that there are dark specks associated with the tan-coloured areas, which are unlikely to be artefactual (chance deposits of dust etc) given they are absent for all intents and purposes in the less-strongly coloured non-image areas?
Flour particles, toasted?

(click on picture to see enlarged version)

A working hypothesis:

Working hypothesis. There are (or were, before the 2002 conservation measures, including that unforgivable hoovering) a scattering of dark-coloured particles on the TS concentrated mainly in the image-bearing regions, with far fewer in non-image regions.

An analysis of those particles would show them to be a substance that has been rendered yellow or brown by thermal energy ("heat" in common parlance). A possible candidate might be white flour particles  – an intentional additive – one that  acquired colour via a Maillard reaction, thus contributing to the image-forming process and  hence its heterogeneity and complexity.

Do they match what we see in the Mark Evans pictures?

As ever, more and more work beckons. First, one will need to do microscopy on the flour-coated  imprinted linen to see what happens to the appearance of individual flour particles, and whether or not they match the specks one sees in the above Mark Evans pictures, at least in terms of size.

And what did McCrone see?

Then comes the difficult part: to track down such papers are available online from the Walter McCrone Microscopy Institute on the studies he did on sticky-tape samples supplied by Ray Rogers. I definitely recall seeing one summary that had a long long list of the different types of particle he had identified.

One wonders what he would have made of those dark specks we see above if indeed they were flour or some other ‘food’ type particle that had undergone a Maillard reaction. One imagines it would take some fairly sophisticated kind of spectrographic microscopy  to make a positive identification, but that is not my area, so there’s a steep learning curve that will need to be climbed to make headway.

Colin Berry: Maybe It’s A Maillard Reaction After All

October 27, 2014 18 comments

Oh, and go boil your head.

From the blog postings of Colin Berry:

It has clear advantages over Mode 1, [discussed above]. in that ANYTHING with 3D properties can in principle be imprinted, not having to be heated. That might be bas relief templates and/or fully 3D statues.  It may even conceivably have been a person, living or dead.  All that was needed was a coating of white flour (or a comparable dry powdered substance providing reducing sugar and amino groups), probably with a binder material to ensure even coating (the vegetable oil in the present modelling, but other options exist).

But I don’t see how with 3D statues, bodies and whatnot, we are not facing the well-understood contact-wrap-around problem. What am I missing?

But there’s a tricky step in the procedure – namely the final roasting of the flour-imprinted linen that has to convert the coating to tan-coloured melanoidins (Maillard reaction products) without too much dicoloration of the linen. It can be done in  principle, on a small scale laboratory basis, given the exceptional chemical and thermal stability of cellulose, by far and away the major component of linen fibres, relative to the starch, proteins lipids etc of wheat flour.

There’s a great deal to think about right now. Best to stop here and post the experimental results. Maybe others can see things I have missed that might offer a way forward through this thicket of new possibilities, each with its own unique difficulties.

To those who claim I select and/or manipulate experimental data I say this. Go boil your heads (old English expression of endearment).

The Devolution and Evolution of a Maillard Reaction Image Hypothesis

October 3, 2014 17 comments

You can’t use up creativity. The more you use, the more you have.
                                                                                   — Maya Angelou

imageColin Berry’s creative juices of lemon pouring forth from his Science Buzz blog:                

Let’s assume, for the sake of argument, that I’ve got the chemistry right, i.e. that the TS image was created by a binary mix of lemon juice (or some other source of active aldehyde) and protein (or some other source of amino acids), and that elevated temperature was required to produce a Maillard non-enzymatic browning reaction.

What about the technology? How might the chemistry have been achieved while at the same time imprinting the negative image of a man that is both exceedingly superficial and which responds well to modern 3D-rendering software (e.g. ImageJ)?

What follows is pure speculation, but one has to start somewhere.

[ . . . ]

. . . So what Rogers conjectured as a starch impurity coating was in my model a protein coating that provided the amino (-NH2) groups for the Maillard reaction.  Putrefaction amines were not needed in the protein/lemon juice model.

So, there you have it, in a few short paragraphs – the Invisible Ink model -  post-STURP Maillard reaction Mk2, one in which a corpse was non-obligatory – a marriage of science and medieval technology.

Interestingly, the model described allows for a ‘blood before image’ modus operandi  . . .

You should/must fill in the dots by reading Colin’s latest amendment to a posting. CLICK HERE and fast-scroll down to Friday October 3.

Has he got the chemistry right?

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