Talk:Lactose

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Chirality

I find it strange that the chirality of the lactose structure here is different than the one at http://en.wikipedia.org/wiki/Lac_operon. Could this be the wrong structure?

80.218.0.145 18:56, 4 March 2006 (UTC) Are you sure the images are ok? compare with Maltose...[reply]

evolution

Why some population became able to metabolise lactose when they could eat cheese or yougurth that doesn't contain lactose? Isn't the calcium contained in cheese not enough for a diet?

I've copied this question to the Wikipedia:Reference desk#Lactose, where this question is more likely to be answered. --David Iberri | Talk 17:42, Dec 15, 2004 (UTC)

I recall reading somewhere that House Cats also have this mutation allowing milk to be used into adulthood. True?

I thought lactose tolerance was also significantly present in those parts of Africa with a long history of cattle raising.

Lactose, whats its purpose???

hey im doing a presentation on lactose for my as level in biology and i was wondering if any one could help. im looking for information on how lactose if formed and its reason for what it is. Why is lactose important to us? chris

The same project

I need the answers to the exact same questions, but just can't find anything... daniel.

== Seriously. Why lactose is produced by the body for inclusion in milk should be one of (if not THE) primary subjects for this article. Typing queries such as "why is lactose in milk?" or "why does milk contain lactose?" in any search engine merely brings up links to lactose intolerance.

Please, somebody make this addition. People know what a beta 1-4 glycosidic linkage is and how it relates to galactose, but they don't know the purpose of lactose? c'mon —Preceding unsigned comment added by 99.161.123.109 (talk) 06:39, 3 August 2009 (UTC)[reply]

Lactose

Isnt lactose a bacteria that turns milk into cheese or yogurt?... John. —Preceding unsigned comment added by 86.159.83.132 (talk) 13:28, 11 January 2009 (UTC)[reply]

RELATION

does anyone have any idea about how milk could be linked with acidity --Iweus 16:51, 23 May 2007 (UTC)[reply]

Why do they call it "milk sugar"?

This article's an example of how, the more accurate an article becomes, the less useful it is. Check the opening sentence:

Lactose is a disaccharide that consists of β-D-galactose and β-D-glucose molecules bonded through a β1-4 glycosidic linkage.

That's incomprehensible to all persons without a college education and most of those with one. The sentences following it don't do much in the way of breaking things down for the layman, either.

I only came to this article on a redirect from "milk sugar", because all I wanted to know is what "milk sugar" is, as compared to plain' ol' "sugar". Various heroin literature refers to the drug being cut with "milk sugar", and I just wanted to know what that was. Well, although the article is a redirect of "milk sugar", there is no explanation of why it was ever called that, or how "milk sugar" came into usage. Do you find it in a grocery? Or do you find it in a chemist's? Is it sold in heavy paper bags? Is it sold in glass bottles? What does a "milk sugar" product look like? Who makes-- no, WAIT! Who doesn't make "milk sugar", among the domestic sugar manufacturers? Is it used in recipes? What for? Does it replace regular sugar, or do they go together?

See, if you're gonna redirect a title, the subject of that title does require some explanation. --63.25.29.84 13:18, 15 September 2007 (UTC)[reply]

I completely agree. Unless one has taken college level courses in biology, it is unlikely that they would know what glycosidic linkages are. The intro needs to be non-technical; the technical description can be moved to a section on the chemistry of lactose. As it stands, it is to the average person entirely jargonistic. Fuzzform (talk) 01:45, 6 December 2007 (UTC)[reply]

Thanks! I see the article has been improved in this regard. --63.25.248.176 (talk) 17:58, 24 February 2008 (UTC)[reply]

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Drawing of glucose ring in lactose is incorrect

One of the oxygens in the glucose ring is in the wrong position. If you know how to count the carbons in the glucose, it's the carbon #1. If you just look at the picture, look at the lowest oxygen in the picture, and move one carbon right. The oxygen connected to that carbon should be in the "down" or equatorial position.

Twocreativenerds (talk) 22:21, 10 October 2008 (UTC)twocreativenerds[reply]

I think the figure also depicts lactose, but it is in the other anomeric form (alpha instead of beta). --Itub (talk) 09:52, 17 October 2008 (UTC)[reply]

Raw milk info spamming

I'm trying to centralize the discussion for now at Talk:Raw_milk#Moved_to_talk_for_discussion --Ronz (talk) 03:05, 19 May 2009 (UTC)[reply]

percent of milk by weight

The article as it stands contradicts itself, by stating "Lactose makes up around 0-8% of milk (by weight)" in the intro, and "Lactose makes up about 2-8% of milk by weight" in the Isolation section. What's going on here? --Keithonearth (talk) 22:01, 8 January 2014 (UTC)[reply]

Who discovered lactose?

I have found sources that claim that Fabrizio Bartoletti (1650-1707) DID discover lactose, and other sources that claim that he did NOT discover it.

This source says that he did NOT discover it: Johann Beckmann with William Johnston, trans., A History of Inventions and Discoveries , 2nd ed., (London, England: 1814), vol. 4, pp. 599-603.

This source says that he DID discover it: E. O. Whittier (April 1925) "Lactose", Chemical Reviews, 2 (1) : 85-125. See: American Chemical Society.

The 1619 edition of Bartoletti's book definitely does NOT mention lactose; however, Whittier claims that a later edition (ca. 1628) does mention it. I'll try to find that later edition. Cwkmail (talk) 05:29, 1 May 2014 (UTC)[reply]

After much searching, I finally found Bartoletti's procedure for extracting lactose from whey. Everyone had been looking in the wrong place. It did not occur in his book Encyclopaedia hermetico-dogmatica (1619). Instead, the procedure occurs in his book of 1633, Methodus in dyspnoeam … [Procedure for asthma … ], (Bologna ("Bononia"), (Italy): Nicolò Tebaldini for the heirs of Evangelista Dozza, 1633), p. 400. There he states: "Manna seri hæc. Destilla leni balnei calore serum lactis, donec in fundo vasis butyracea fœx subsideat, cui hærebit salina quædam substantia subalbida. Hanc curiose segrega, est enim sal seri essentiale; seu nitrum, cujus causa nitrosum dicitut serum, huicque tota abstergedi vis inest. Solve in aqua propria, & coagula. Opus repete, donec seri cremorem habeas sapore omnino mannam referentem." (This is the sweet stuff of whey. Gently distill whey via a heat bath until the buttery scum settles to the bottom of the vessel, to which salt [i.e., precipitate] some whitish substance attaches. This curious [substance once] separated, is truly the essential salt of whey; or, on account of which salt, is called "whey salt", and all [life] force is in this expelled. Dissolve it in [its] own water and coagulate. Repeat the operation, until the cream's whey has only the taste of the restored sweet stuff.) Cwkmail (talk) 05:41, 29 May 2014 (UTC)[reply]

Assessment comment

The comment(s) below were originally left at Talk:Lactose/Comments, and are posted here for posterity. Following several discussions in past years, these subpages are now deprecated. The comments may be irrelevant or outdated; if so, please feel free to remove this section.

2008-feb-05: The current drawing is incorrect. The bridging oxygen should be directly connected to the left sugar ring, not via a methylene. 193.67.131.130 (talk) 14:15, 5 February 2008 (UTC)[reply]

Last edited at 14:15, 5 February 2008 (UTC). Substituted at 21:32, 29 April 2016 (UTC)

References/Citations Needed

This article is missing a lot of references in the Structure and Reactions, Isolation, and Metabolism sections. This writing is awkward and does not have reliable sources.

In addition to missing citations, the first citation: http://www.stevecarper.com/li/list_of_lactose_percentages.htm is not a legitimate source and should be removed.

RichardsonEJ (talk) 23:16, 5 February 2018 (UTC)[reply]