Scientific article on cold process artisan soap qualities (2018)

[Mobjack Bay]

Natalia Prieto Vidal * , Oludoyin Adeseun Adigun, Thu Huong Pham , Abira Mumtaz, Charles Manful, Grace Callahan, Peter Stewart, Dwayne Keough and Raymond Horatio Thomas *

School of Science and the Environment/Boreal Ecosystem Research Facility, Grenfell Campus, Memorial University of Newfoundland

The Effects of Cold Saponification on the Unsaponified Fatty Acid Composition and Sensory Perception of Commercial Natural Herbal Soaps.

Molecules 2018, 23, 2356; doi:10.3390/molecules23092356

Has anyone else read this paper? I gave it a shot although I had to google my way through a lot of the fatty acid notation. It can be downloaded as a pdf, here. The conclusions for tests done with the three soaps pictured and variations are below.

A is Base Bar (BB) with no color or EOs; B is Forest Grove, with green clay and EOs; C is Hibiscus Rose Hip with pink clay, EOs and Hibiscus tea. They also added a proprietary mix that included rosemary extract to some of the test bars.

Conclusions:
There is currently a paucity of information in the literature related to how the content of unsaponified fatty acids in natural herbal soaps manufactured using cold saponification influences the sensory perception and consumer’s preference or acceptance of natural soap products. The output from this study attempted to fill this knowledge gap. We observed commercial natural soaps manufactured from plant oils and additives as feedstock by cold saponification retained significant levels of unsaponified fatty acids, phenolic compounds, and antioxidant activities in the final products. The majority of the unsaturated fatty acids present in the feedstock remained unsaponified in the natural soaps after manufacturing by cold saponification. The unsaponified monounsaturated fatty acids (C18:1n9) appeared to be the most responsive to the variation in the choice of vegetable oils used as soap feedstock during manufacturing via cold saponification. Addition of additives in the soap formulation had a significant effect on the percent change or retention of the feedstock fatty acids as unsaponified fatty acids in the finished products. Both the antioxidants and phenolics were associated with the retention or levels of C18:1n9 and C18:3n3, but not C18:2n6 unsaturated unsaponified fatty acids in natural herbal soaps manufactured via cold saponification. These findings suggest cold saponification is an effective approach to enhance the levels of unsaponified fatty acids, phenolics, and antioxidants in hand-made natural soaps. Appealing smell was the greatest influencer of consumer preference, while color and appealing smell were the best indicators of natural soaps’ estimated pricing and consumers’ perceived quality, and consequently acceptability. These findings are of major significance to artisanal production of natural herbal soaps because antioxidants, polyphenols, and unsaponified unsaturated fatty acids appear to be major determinants of natural soap quality, consumer perception, and preference of the final products. One of the most significant findings in this study was that the base bar used as control in this study had the best overall preference compared to the other soaps formulated with specialty or exotic plant oils as feedstock and additives. These findings suggest some of the more exotic additives and specialty oils used to manufacture hand-made natural soaps may not be producing the perceived consumer acceptance or preference, and that artisan natural soap makers should give careful considerations to their use during the manufacturing of hand-made natural soaps. This work provides some baseline information regarding natural hand-made soaps manufacturing, which is very sparse in the scientific literature. The hope is that the information presented will stimulate additional studies by other researchers in the scientific community, to further improve the knowledge that may be of value to the growing specialty hand-made soap industry.

 

[runnerchicki]

Reading this was like trying to catch a greased pig. Just as I think I've got it - it slips away. I will wait for someone to summarize LOL.

 

[Mobjack Bay]

Reading this was like trying to catch a greased pig. Just as I think I've got it - it slips away. I will wait for someone to summarize LOL.

That is the short version! The actual paper is dense, very dense. I found it surprising that the majority of the unsaturated fatty acids did not saponify. If that’s the case, why bother to superfat? The plain white soap did best in their preference test, but just barely. Soap scent was important, but I think they found that the unscented bar was preferred over the ones with EOs. I took notes to help me remember what they were reporting, but got tired before I read the sensory attributes testing results and methods. I’ll leave the review of those sections for another day.

 

[DeeAnna]

I read this one awhile back and found the paper confusing and annoying. Here's one example from the conclusions you provided --

"...Appealing smell was the greatest influencer of consumer preference, while color and appealing smell were the best indicators of natural soaps’ estimated pricing and consumers’ perceived quality, and consequently acceptability.

These findings are of major significance to artisanal production of natural herbal soaps because antioxidants, polyphenols, and unsaponified unsaturated fatty acids appear to be major determinants of natural soap quality, consumer perception, and preference of the final products...."

Okay, researchers -- you can have it one way or the other, but you can't have both.

I get the feeling their results told them one thing -- consumers like good smelling soap -- but they could not really accept that at face value. Instead, they keep stating their bias in favor of those "crunchy" antioxidants, etc.

I used to be a reviewer for papers in my field of research. It can be exhausting and you don't get paid and the authors are often not very appreciative. It can be a thankless job. But it's important.

This paper comes across as one that didn't get the benefit of an honest, thoughtful peer review. I would have asked the authors to review their data again and report what their findings truly were ... not on what they wanted their findings to be.

edit -- And their finding that most of the unsaturated fatty acids were unsaponified suggests to me their superfat was way high and/or it is an artifact of how they made their soap. I'm not convinced we can apply this to handmade soap in general. I'm not going to wade through the report again to figure that out.

 

[Rsapienza]

WOW.....I just read this the other day!! Not an easy read. If I remember correctly, scented soaps were the favorite.

 

[Mobjack Bay]

I read this one awhile back and found the paper confusing and annoying. Here's one example from the conclusions you provided --

"...Appealing smell was the greatest influencer of consumer preference, while color and appealing smell were the best indicators of natural soaps’ estimated pricing and consumers’ perceived quality, and consequently acceptability.

These findings are of major significance to artisanal production of natural herbal soaps because antioxidants, polyphenols, and unsaponified unsaturated fatty acids appear to be major determinants of natural soap quality, consumer perception, and preference of the final products...."

Okay, researchers -- you can have it one way or the other, but you can't have both.

I get the feeling their results told them one thing -- consumers like good smelling soap -- but they could not really accept that at face value. Instead, they keep stating their bias in favor of those "crunchy" antioxidants, etc.

I used to be a reviewer for papers in my field of research. It can be exhausting and you don't get paid and the authors are often not very appreciative. It can be a thankless job. But it's important.

This paper comes across as one that didn't get the benefit of an honest, thoughtful peer review. I would have asked the authors to review their data again and report what their findings truly were ... not on what they wanted their findings to be.

edit -- And their finding that most of the unsaturated fatty acids were unsaponified suggests to me their superfat was way high and/or it is an artifact of how they made their soap. I'm not convinced we can apply this to handmade soap in general. I'm not going to wade through the report again to figure that out.

I agree that there are a lot of confusing statements in the paper. It may be that the author is not a native English speaker, or a graduate student, but then the onus is on the last author, the head of the research group to ensure that the writing is clear. A statement at the end of the article indicates assisted in writing the manuscript and reviewed and edited the manuscript.

I relied heavily on the data in the figures and tables to evaluate their results and conclusions.

The methods they used to make the soap are detailed in the paper and are quite usual relative to those we would use. They state that the superfat was 6%, but the one number they do not reported is the amount of lye used. They made replicate batches of soap and worked with a commercial scale producer of cp soap. I lean towards assuming they got the lye right given how common it is to make soap in chemistry 101.

According to Table 3, based on the preferences of 59 untrained students, staff and faculty of the university, the testers on average preferred the “scent” of the control soap (BB).