Wikipedia:Reference desk/Archives/Science/2022 May 7

= May 7 =

Previously frozen Acid (Yogurt) Whey, for fermentation
I have been making yogurt, using the cold start method, as described at and several other sites, using Fairlife Ultra-filtered milk (whole) or Kirkland/Costco Ultra-pasteurized (2%) milk, with a commercial active-culture yogurt as a "starter". I strain the excess whey, to produce "Greek" style yogurt. I understand that "acid whey" from yogurt can be used, at home, to ferment vegetables, among other uses. I have been storing excess whey in the freezer, hoping to use in the future.

My question: Does the freezing of acid whey, and the subsequent, (albeit gentle and slow, in the refrigerator) thawing process disturb the ability of the whey to ferment vegetables? Summer vegetable season is approaching, here in the Southeastern US, but I don't want to attempt to ferment cabbage, cucumbers and such, only to have food rot/go to waste. Frozen, active-culture yogurt "starter" revives and works fine, for new yogurt batches, but I'm not sure about the whey, for fermentation of vegetables. Somewhat "whey" over my head! Not here on a daily basis, please ping, if possible. Thanks very much,  Tribe of Tiger Let's Purrfect!  03:57, 7 May 2022 (UTC)


 * If the fluid is salty enough, the desired fermentation will take place regardless of the liveliness of any lactic-acid producing bacteria in the fluid, since there will be enough on the vegetables to start the process. The salt inhibits the growth of other, unwanted microorganisms. The point of using whey, if I understand correctly, is that there is already a substantial amount of lactic acid present, giving the fermentation process a head start before unwanted growth spoils the food. This blog post argues that salt is better than whey anyway. If you are in an experimental mood, you might experiment with using your whey with different amounts of added salt. --Lambiam 08:45, 7 May 2022 (UTC)
 * In this article the authors added L. plantarum by various methods to ice cream being produced and tested which fraction survived the successive production steps. The method closest resembling the whey situation was the addition of "prefermented skim milk". Then, assuming the "Log" in "Log cfu/g" in Figure 2 stands for the common logarithm (base 10), the reported reduction in viable L. plantarum organisms by the steps of "aging" for 24 h at 4°C followed by freezing for 15 min at −5°C was by about a factor of 4. I would expect (but am not sure) that most of the damage is done at the moment of freezing, and that keeping the stuff, once it is frozen, in that state for an extended period at a relatively steady temperature will not make much of a difference. --Lambiam 19:26, 7 May 2022 (UTC)
 * I didn't realize that L. plantarum was already present on vegetables...duhh. The blog is helpful, from a "practical use" view point. I like to drink whey, adding a few dashes of salt. I know it is acidic, by the flavor. (Should unearth my Ph test strips). The "ice cream" article was over my head, thanks for providing a simplified summary. So, frozen whey may still assist the fermentation process, if a boost is needed, depending on home temperature. I will experiment with whey and/or salt. You have been extremely helpful, thank you so much!  Tribe of Tiger Let's Purrfect!  21:34, 7 May 2022 (UTC)

Deciphering a product label
I am trying to decipher a product label. This is the product:. Specifically, the 320-count bottle. (I think that you have to specifically click on the 320 Count Selection Box, located over to the right of that page.)


 * [Bullet 1] One of the labels says Serving Size 5 Capsules


 * [Bullet 2] One of the labels says Active ingredient (in each capsule): Psyllium husk approximately 0.52 g


 * [Bullet 3] One of the labels says One serving of this product has 1.8 grams of this soluble fiber (that is, soluble fiber from psyllium husk)

OK ... so ... the third bullet point says:


 * One serving of this product has 1.8 grams of this soluble fiber (that is, soluble fiber from psyllium husk)

Since Serving Size 5 Capsules ... the above statement can be restated as:


 * 5 Capsules of this product has 1.8 grams of this soluble fiber (that is, soluble fiber from psyllium husk)

Dividing by five ... the above statement can be restated as:


 * 1 Capsule of this product has 0.36 grams of this soluble fiber (that is, soluble fiber from psyllium husk)

This last statement doesn’t seem to square with Bullet Point Number 2 up above. So, can someone please clarify? What am I missing? I am trying to determine how much of the “medicine” or of the “product” is in each single capsule. In other words, if I take one capsule, I am getting ___ (how many grams) ___ of daily fiber / psyllium husk from that one capsule? Thanks. Joseph A. Spadaro (talk) 21:53, 7 May 2022 (UTC)


 * Why would you assume that P. husk is entirely made of soluble fiber? Obviously, it includes other things as well. Anyway, this isn't medicine any more than a banana is medicine (I'm sure there's some website that claims it is). Imagine Reason (talk) 22:44, 7 May 2022 (UTC)
 * The FDA has approved several health claims for this product that have not been approved for bananas; see . You may be able to obtain funding from distributors of bananas to examine whether they offer comparable health benefits. --Lambiam 06:51, 8 May 2022 (UTC)
 * I can confirm the correctness of your computation. If 1 serving (5 capsules) contains 1.8 grams of mucilaginous fibre, 1/5th of a serving (1 capsule) contains 1.8/5 = 0.36 grams of the good stuff. So this amounts to 0.36/0.52 × 100% = about 70% of the husk. According to this web page, the remaining 30% is insoluble fibre, which isn't bad for one's health either. --Lambiam 07:07, 8 May 2022 (UTC)
 * User:Lambiam ... thanks for your helpful reply. That website link was very helpful.  I guess the part that confused me the most was that the label mentioned "active ingredient".  The term "active ingredient" -- in these labels -- apparently refers to the psyllium husk, and not to the soluble fiber itself.  I would have thought that the "active ingredient" would (should) refer to the fiber itself ... the 70% of the husk that is soluble.  And I would have thought that the 30% of insoluble fiber was not particularly helpful or "active".  (So, I guess I was incorrect.)  Hence, the source of my confusion.  Thank you again.
 * Now, a follow-up question, if I may. That website states:  The Academy of Nutrition and Dietetics recommends that women aim for 25 grams of fiber per day, and men should consume 38 grams of fiber per day.  So, let’s just assume -- hypothetically, for purposes of this conversation -- that a male obtains all of his daily fiber from these capsules, and from no other source whatsoever.  Which below would be the better / more appropriate calculation?
 * * Calculation A -- daily goal of 38 grams per day / 0.52 grams of active ingredient (psyllium husk) per capsule = 73 capsules per day needed
 * * Calculation B -- daily goal of 38 grams per day / 0.36 grams of soluble fiber per capsule = 106 capsules per day needed
 * Again, just hypothetical. I'm really just trying to figure out the correct math, behind all this.  Thanks!    Joseph A. Spadaro (talk) 19:24, 8 May 2022 (UTC)
 * Based purely on the statement I'd go with A. The husks are all fibre, a mix of soluble and insoluble fibre. Neither type is digested. However, psyllium is unusual in its low percentage of insoluble fibre. The research the advice is based on may have involved more balanced diets with a much higher percentage of insoluble fibre, and it is not obvious that the results can be extrapolated to an extraordinary diet in which psyllium husks are the sole source of fibre. To be on the safe side, one might therefore even argue for C -- daily goal of 38 grams per day / 0.16 grams of insoluble fiber = 238 capsules per day. --Lambiam 21:54, 8 May 2022 (UTC)