Alpha and Beta Amylase from Green Bananas

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BrewCanuck

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So I've read through all of the threads in this subforum, trying to digest as much info as I can. I know that there were some threads on using bananas in the mash but IIRC they all referenced using RIPE bananas. Has anyone tried using green bananas?

I ask because I read the following abstract from Journal of Food Science
Volume 46, Issue 5, pages 1400–1403, September 1981:

Following subcellular fractionation and centrifugation, the amylase activity was located in the cytosol fraction of banana fruit. Over 80% of the observed activity (15—20 units per mg of protein) was attributed to α-amylase. The activity of β-amylase was tenfold lower and starch phosphorylase activity was low (17 μg inorganic phosphorus released per mg protein per 24 hr.). The activity of amylase in crude preparations was stimulated 40% by calcium ions. The amylase preparation, which was very stable at 4°C, hydrolyzed soluble potato starch and banana starch at similar rates. Maximum activity was observed between pH 6—7. The energy of activation of hydrolysis was 9.74 Kcal/mole. Amylase was quite active up to 62°C but rapidly lost activity above this temperature. There was an approximate twofold increase in amylase during the initial phase of ripening.

I'm just wondering if the full article describes how they get the "crude preperation" of enzymes, and if we could make it feasable.

And it seems there may be some actual number for DP of bananas in the actual article. Does anyone have access to the Wiley Online Library that can pull this down?

Here is the link to the article.

Thanks
 
Well, it's kinda moot, because even if you can get alpha and beta amylase from green unripe bananas, you need more than just diastatic enzymes to make a good beer out of grains; you need protease and beta-glucanase as well unless you're just using corn and rice. Also, even if the bananas have diastatic power of their own, they also have to convert their own starch before they can convert that of any other grains...you're probably always going to need more bananas than grains in the mash. What's more, bananas don't have their own pectinase, so you're gonna have to add that unless you want a hazy beer. Lastly, why bother with bananas when you can get alpha and beta amylase enzymes off the shelf? You can get enough for ~6 or 7 batches for around $8 from EC Kraus. And if you pester your LHBS enough, they might even be able to get it for you cheaper.
 
BrewCanuck I had a similar thought that directed me to this forum. I'll read this article and consult some o-chemists that I know.

"they also have to convert their own starch before they can convert that of any other grains"

I don't agree with this statement. The enzyme activity is based more on temp, pH, and availability.
 
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