4 replies to this topic

[poppysnoss]

I am working on a project at the moment, whereby the scenario is a yeast problem in a cake factory. A proportion of cakes produced are producing bubbles under the sugar paste, which appear to be due to yeasts.

Does anyone have any insight into what might cause this type of problem, ie could it be linked to raw materials? Or equipment? I have spent many an hour trawling the internet but can't come up with anything useful.

Many thanks in advance

Pops

[a_andhika]

I am working on a project at the moment, whereby the scenario is a yeast problem in a cake factory. A proportion of cakes produced are producing bubbles under the sugar paste, which appear to be due to yeasts.

Does anyone have any insight into what might cause this type of problem, ie could it be linked to raw materials? Or equipment? I have spent many an hour trawling the internet but can't come up with anything useful.

Many thanks in advance

Pops

Dear Pops,

Although I am not an expert on this matter, but I hope I can give you some hint.

As you know, when yeast consume and metabolize sugar, they produce ethanol and CO2, which causing bubbles. It was a common reaction in bread industry, and I am sure you know it better. Just for comparison, I found some interesting informations on the net:

http://www.botham.co...bread/yeast.htm

The primary function of yeast is to supply carbon dioxide gas which inflates the dough during proof and the early stages of baking (oven spring).

Carbon dioxide cannot form a gas bubble on its own it requires a 'nucleating site' (i.e. somewhere it can gather to form a bubble). In fizzy drinks microscopic projections on the side of the bottle provide those sites which is why when you release the pressure as you open the bottle you see 'streams' of gas running from the sides. In bread dough the nucleating sites are provided by the nitrogen gas bubbles trapped in the dough during mixing. The oxygen from the air having been used up by the yeast.

During proof stages the carbon dioxide goes into solution until the solution is saturated and then any more which is generated makes its way into the nitrogen gas bubbles which grow in size and the dough expands. The more yeast and the warmer the temperature the faster the expansion - we get oven spring because the maximum gassing rate occurs at 40-45C.

From the link above, I quoted some informations which sayin' that the expansion increase when the temperature increase. So lowering the temperature perhaps may solve your case. Or... is it possible to dissipate the Nitrogen out of the dough? So the 'nucleating site' won't be formed?

If the temperature and Nitrogen issue won't work, maybe you can change the sugar. Sucrose is very best for making foam, and glucose didn't make the yeast have the most foaming. As for the rest, you can read it on this link:

http://www-saps.plan...ords/rec358.htm

And it always been a ritual for me to asking Mr. Wiki when I have some problem. Here Mr. Wiki goes:

http://en.wikipedia.org/wiki/Yeast

On that link, it said that yeast will die on high temperature. A bit contrary if compared with the first link (Botham's Educational Page), IMO. But probably, what mentioned in the first link is the temperature will trigger the expansion, meanwhile the yeast had long gone...

Mr. Wiki also give us some advice on choosing the type of yeast, maybe it can helps you out:

http://en.wikipedia.org/wiki/Baker's_yeast

Last but not least, I found this remarkable literature about CO2 production during the growth of yeast. Its very interesting, although I dont know it might be useful for you or no:

http://www.plantphys...int/7/1/139.pdf


Well, that's all I can do for now. I am willing to have a further discussion 'bout this matter


Regards,


Arya

Edited by a_andhika, 23 September 2009 - 02:13 PM.

[SaRaRa]

Dear pops,

In my short "free" time I found those books. Unfortunately time is a luxury for me so you have to search in detail in the following books by yourself.

Bakery Technology and Engineering

Technology of Cake Making

Bakery Products: Science and Technology

Handbook of foodproducts manufacturing

The science of bakery products - CAKES

Good luck!

Filip

[Hongyun]

On that link, it said that yeast will die on high temperature. A bit contrary if compared with the first link (Botham's Educational Page), IMO. But probably, what mentioned in the first link is the temperature will trigger the expansion, meanwhile the yeast had long gone...

Hi Arya,

Yeast generally perform best at warm temperature, optimum @ 40-45°C, which I think is what the first link is trying to say. The higher the temperature, the faster they multiply, but the temperature must not be higher than 45°C or the growth will slow down and eventually die out as the temperature continues to climb.

I sometimes make my own wine, so I know abit. If I leave the juice to ferment at low temperature (good aroma fruity wine), they take a long time to complete. But if I leave it at room temperature, it will produce bubbles like nobody's business and the fermentation process takes less time to complete... But if the temperature gets too high, e.g. baking bread, they will die just like normal mesophiles.

Hi Pops,

The problem may lie in raw materials with high moisture content or are in liquid state as Yeast require more water to survive as compared to bacteria and molds. Perhaps you can "check" the water used to make the sugar paste. Or maybe the equipments are not properly sanitized and dried before mixing.

The cake should be relatively safe, that is if it is baked properly and all yeast has been deactivated by high temperature.

On top of Filip's google search, here's more!

Handbook of food spoilage yeasts

Baked goods freshness: technology, evaluation, and inhibition of staling

Edited by Hongyun, 24 September 2009 - 02:54 PM.

[poppysnoss]

Thanks for all your input, folks! Am off to check out the links.

Very much appreciated.