Ainaga
Member
i’m going to try and put my thoughts together on this subject so that i can make myself coherent in writing in order to explain how the idea under title came about, and in a way possible to me connect the different subjects touched on here, so that it doesn’t appear like i am throwing a bunch of unrelated information together. if this precisely has been discussed previously, i haven’t found where, so i apologize in advance if such is the case. if you can point me in the direction where my questions can be answered, or the idea that this study elaborates, i appreciate that. i could've asked a simple question, but i wanted to give a little background and also mention some of the points in the study i deemed most important. some files are attached for reference.
recently i read a post by haidut where i read him asking for advice on how to increase his protein intake at work. this lead at some point to a discussion, if i’m not mixing threads, about exogenous lactic acid. also recently though before that i read him discussing with amazoniac -in what to me was somewhat obscure language- scientifically and (perhaps) philosophically the language being used in a study that talked about lactic acid where they should have been talking about lactate instead. this was my interpretation, and led to the following; whether my interpretation was correct or not, i was brought to the problem of lactic acid bacteria metabolism, and eventually to the main idea here.
i reckon many of you have read, because it involved haidut, the discussion about milk, yogurt, kefir, skyr, cottage and ricotta cheeses, whey, acids, etc. what i could gather from the discussion was that amongst things that people are trying to avoid is lactic acid, on one side, and bacteria, on the other; both based on firm peaty notions. the discussion branched out from that. it must have been an old thread, i didn’t check its proper date, but i never received an answer to the question of whether one thought making cheese with low fat milk and rennet would produce your desired product of a relatively good protein low in fat and of a neutral and sterile nature, which could then be mixed with energy to create sensible food.
after following these threads and the thoughts that came in the process, it occurred to me -perhaps because i bake, make kombucha, prepare food in general, including cheese from raw milk, and “ferment” things in other ways- that a neat way to experiment with milk and to make a product more moderate in so far as extremes go -anything overly sour and hyper-colonized being an extreme- would be to respire milk.
so we get to the title. i wanted to know if it was possible to “respire” milk instead of fermenting it -the latter being, as far as i know, the only way traditionally done. again, in my years delving into traditional international food culture i have never come across this concept.
according to the following study -which disclaims at the end that their research goes back to the year 2000 and is sponsored- it could very well be possible, if milk is used as the sugar source, and in the case of raw milk if it is also used as the source of bacteria, while having all happen inside the human host, the in vivo medium. i must have simply searched ‘respiration milk’, and this was one of the first hits that appeared, and the study pretty much answered most of my initial questions, answered others i hadn’t posed, plus gave me another set of questions to ponder and posit here.
the definitions state -and this is presupposed by the study of course- that fermentation produces lactic acid without the presence of oxygen, while respiration produces carbon dioxide and water in the presence of oxygen. we can see at the outset in which side ray is here. the study is comparing the ability of different strains of facultative lactic acid bacteria to use oxygen in order to produce (or fail to produce) various metabolites at various speeds over various life and health spans, with the variable addition of the substrates heme and/or K2. they indeed found that there were species in all groups, and that later the fate of species like lactis for example influences the fate of other species colonies.
lactic acid bacteria (LAB) were placed into three categories of respiration: those needing heme, those needing heme and exogenous menaquinones, and finally those that cannot respire.
the authors at some point say the most striking feature of respiring bacteria is their increased cell count and long-term survival. when we think of bacteria we think of endotoxin, though not everyone on this forum is convinced that lower bacterial counts and antibiotics are good in general. granted other metabolites beside lactic acid are produced during fermentation, a smaller population of fermenting LAB might still imply some benefit even when total counts are similar. what’s more, is it desirable indeed to increase the count of bacteria producing carbon dioxide and water, regardless of fermentation counts? is it the case that the shifting ratio of respiring LAB to fermenting LAB increases co2 and water in the body in a way that can be useful to us? and if what they need to accomplish this is oxygen, how de we also increase oxygen in the body bioavailable to them? without hyperventilation, can increased carbon dioxide levels on their part serve to support an increase in their hosts oxygen capacity? if so then the phenomenon of increased cell count and long-term survival would imply a desirable outcome.
again, back to the practical application, and this is ultimately the question that leads this thread: would ingesting respired milk be more beneficial than ingesting fermented milk.
look at table 2 providing “real” potential applications of LAB respiration. food products lists aromas, which tells us the product resulting from “respired milk” will be different, perhaps even (also) pleasant. one aroma, acetoin curiously also stimulates plant growth. it and diacetyl, turn out to be more neutral than lactic acid, and thus the ph of the medium (potentially the host) is increased. in addition, their conversion from pyruvate accounts for 20% of glucose carbon used for respiration; so a considerable part, with expected significant results.
under health and diet we have menaquinone production by some strains (good), utilization of (necessary but toxic) heme (required by LAB for respiration) (good), and resulting colony robustness -which in the case that we find that they should stay in the body, to produce energy and detoxify us, is also good.
while the study focuses on oxygen as the activator of respiration, it also suggests other electron acceptors beside oxygen, such as fumarate and nitrate. again, on the practical question of producing respired milk, does anyone also think that it would be easier to supply the latter two than it is to supply oxygen? for that is a question i wanted to pose to engineers in this forum. how do you oxygenate milk? is there a practical way to do this at home? an outshoot of this study could put different electron acceptors to the test, to see which produces a more favorable outcome.
also check out how the respiration chain generates NADH oxidase, recycling NAD+. the more NAD+, the lower its ratio to NADH, which is the cofactor required by lactate dehydrogenase for lactic acid production. meaning, the more NADH oxidase, therefore, the lower the amount of lactic acid production. sensible logic.
interesting also how they say that limited changes in gene expression observed during respiration point to the importance of metabolites in the strength and survival of the LAB. as pointed above, the depletion of NADH is the main player here. pyruvate then breaks down into the aforementioned aromas. in a very peaty way, the authors point to the importance of metabolites in the bio-history of the cells, beyond their genetic makeup. equally, not the LAB species or their numbers inside the host body, but the metabolites they produce.
LAB are limited in that they must begin fermenting some form of sugar carbon before some NADH can be generated. so the two processes, fermentation and respiration would go hand in hand. the question would then be which sugar alcohol? the study slightly touches on that as well.
as to the taste of respired milk, in general terms it would be less sour than yogurt, and bubbly, no? bland or slightly sweet? i guess it would depend.
what is most interesting to me is that such a simple idea hasn’t been explored more. the authors claim that “for those working on LAB, respiration constitutes a radical departure from conventional growth conditions”, and that “this subject has received little scientific attention”. they further claim there is no model for these bacteria relying on exogenous cofactors. i extrapolate that to mean that, by consequence, respiring milk is not a thing yet. this study was published in 2012, so there’s a good chance some of you have pondered this before and all of this has come to fruition already.
so, in short, i wonder if you can suggest ways to do this at home. we know that we add heme, that we add some form of k2, but how do you add oxygen to the milk in order that it is available to the respiring LAB?
recently i read a post by haidut where i read him asking for advice on how to increase his protein intake at work. this lead at some point to a discussion, if i’m not mixing threads, about exogenous lactic acid. also recently though before that i read him discussing with amazoniac -in what to me was somewhat obscure language- scientifically and (perhaps) philosophically the language being used in a study that talked about lactic acid where they should have been talking about lactate instead. this was my interpretation, and led to the following; whether my interpretation was correct or not, i was brought to the problem of lactic acid bacteria metabolism, and eventually to the main idea here.
i reckon many of you have read, because it involved haidut, the discussion about milk, yogurt, kefir, skyr, cottage and ricotta cheeses, whey, acids, etc. what i could gather from the discussion was that amongst things that people are trying to avoid is lactic acid, on one side, and bacteria, on the other; both based on firm peaty notions. the discussion branched out from that. it must have been an old thread, i didn’t check its proper date, but i never received an answer to the question of whether one thought making cheese with low fat milk and rennet would produce your desired product of a relatively good protein low in fat and of a neutral and sterile nature, which could then be mixed with energy to create sensible food.
after following these threads and the thoughts that came in the process, it occurred to me -perhaps because i bake, make kombucha, prepare food in general, including cheese from raw milk, and “ferment” things in other ways- that a neat way to experiment with milk and to make a product more moderate in so far as extremes go -anything overly sour and hyper-colonized being an extreme- would be to respire milk.
so we get to the title. i wanted to know if it was possible to “respire” milk instead of fermenting it -the latter being, as far as i know, the only way traditionally done. again, in my years delving into traditional international food culture i have never come across this concept.
according to the following study -which disclaims at the end that their research goes back to the year 2000 and is sponsored- it could very well be possible, if milk is used as the sugar source, and in the case of raw milk if it is also used as the source of bacteria, while having all happen inside the human host, the in vivo medium. i must have simply searched ‘respiration milk’, and this was one of the first hits that appeared, and the study pretty much answered most of my initial questions, answered others i hadn’t posed, plus gave me another set of questions to ponder and posit here.
the definitions state -and this is presupposed by the study of course- that fermentation produces lactic acid without the presence of oxygen, while respiration produces carbon dioxide and water in the presence of oxygen. we can see at the outset in which side ray is here. the study is comparing the ability of different strains of facultative lactic acid bacteria to use oxygen in order to produce (or fail to produce) various metabolites at various speeds over various life and health spans, with the variable addition of the substrates heme and/or K2. they indeed found that there were species in all groups, and that later the fate of species like lactis for example influences the fate of other species colonies.
lactic acid bacteria (LAB) were placed into three categories of respiration: those needing heme, those needing heme and exogenous menaquinones, and finally those that cannot respire.
the authors at some point say the most striking feature of respiring bacteria is their increased cell count and long-term survival. when we think of bacteria we think of endotoxin, though not everyone on this forum is convinced that lower bacterial counts and antibiotics are good in general. granted other metabolites beside lactic acid are produced during fermentation, a smaller population of fermenting LAB might still imply some benefit even when total counts are similar. what’s more, is it desirable indeed to increase the count of bacteria producing carbon dioxide and water, regardless of fermentation counts? is it the case that the shifting ratio of respiring LAB to fermenting LAB increases co2 and water in the body in a way that can be useful to us? and if what they need to accomplish this is oxygen, how de we also increase oxygen in the body bioavailable to them? without hyperventilation, can increased carbon dioxide levels on their part serve to support an increase in their hosts oxygen capacity? if so then the phenomenon of increased cell count and long-term survival would imply a desirable outcome.
again, back to the practical application, and this is ultimately the question that leads this thread: would ingesting respired milk be more beneficial than ingesting fermented milk.
look at table 2 providing “real” potential applications of LAB respiration. food products lists aromas, which tells us the product resulting from “respired milk” will be different, perhaps even (also) pleasant. one aroma, acetoin curiously also stimulates plant growth. it and diacetyl, turn out to be more neutral than lactic acid, and thus the ph of the medium (potentially the host) is increased. in addition, their conversion from pyruvate accounts for 20% of glucose carbon used for respiration; so a considerable part, with expected significant results.
under health and diet we have menaquinone production by some strains (good), utilization of (necessary but toxic) heme (required by LAB for respiration) (good), and resulting colony robustness -which in the case that we find that they should stay in the body, to produce energy and detoxify us, is also good.
while the study focuses on oxygen as the activator of respiration, it also suggests other electron acceptors beside oxygen, such as fumarate and nitrate. again, on the practical question of producing respired milk, does anyone also think that it would be easier to supply the latter two than it is to supply oxygen? for that is a question i wanted to pose to engineers in this forum. how do you oxygenate milk? is there a practical way to do this at home? an outshoot of this study could put different electron acceptors to the test, to see which produces a more favorable outcome.
also check out how the respiration chain generates NADH oxidase, recycling NAD+. the more NAD+, the lower its ratio to NADH, which is the cofactor required by lactate dehydrogenase for lactic acid production. meaning, the more NADH oxidase, therefore, the lower the amount of lactic acid production. sensible logic.
interesting also how they say that limited changes in gene expression observed during respiration point to the importance of metabolites in the strength and survival of the LAB. as pointed above, the depletion of NADH is the main player here. pyruvate then breaks down into the aforementioned aromas. in a very peaty way, the authors point to the importance of metabolites in the bio-history of the cells, beyond their genetic makeup. equally, not the LAB species or their numbers inside the host body, but the metabolites they produce.
LAB are limited in that they must begin fermenting some form of sugar carbon before some NADH can be generated. so the two processes, fermentation and respiration would go hand in hand. the question would then be which sugar alcohol? the study slightly touches on that as well.
as to the taste of respired milk, in general terms it would be less sour than yogurt, and bubbly, no? bland or slightly sweet? i guess it would depend.
what is most interesting to me is that such a simple idea hasn’t been explored more. the authors claim that “for those working on LAB, respiration constitutes a radical departure from conventional growth conditions”, and that “this subject has received little scientific attention”. they further claim there is no model for these bacteria relying on exogenous cofactors. i extrapolate that to mean that, by consequence, respiring milk is not a thing yet. this study was published in 2012, so there’s a good chance some of you have pondered this before and all of this has come to fruition already.
so, in short, i wonder if you can suggest ways to do this at home. we know that we add heme, that we add some form of k2, but how do you add oxygen to the milk in order that it is available to the respiring LAB?
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