Diafiltered Skim Milk?

Discussions on general chemistry and chemical engineering, organic chemistry, analytical chemistry, etc.

Diafiltered Skim Milk?

Postby vivian maxine on December 27th, 2016, 8:37 am 

Would anyone understanding chemistry know what "diafiltered skim milk" is? Is it the same as nonfat dry skim milk? I asked our pharmacists and they never heard of it. I tried the internet and all I got was that it is fed to animals. Also there is protest because American producers are selling it to Canadian farmers which is cutting in on the Canadian dairy industry. All of that does not say what it is. I know it is also being used in human food products. I've seen it listed in ingredients.
vivian maxine
Resident Member
 
Posts: 2591
Joined: 01 Aug 2014


Re: Diafiltered Skim Milk?

Postby doogles on December 27th, 2016, 6:04 pm 

Good day to you vivian maxine.

"The prefix dia- occurs in loanwords from Greek ( diabetes; dialect) and used, in the formation of compound words, to mean “passing through” ( diathermy), “thoroughly,” “completely” ( diagnosis), “going apart” ( dialysis), and “opposed in moment” ( diamagnetism)."

In the word ‘dia-filtration’ it is used almost redundantly because filtration is a passing-through process itself.

Nevertheless it has become a well-known process in milk product preparations. The process is used to concentrate skim milk and to isolate certain protein and carbohydrate fractions in order to improve and standardise the taste and texture of certain cheeses and yoghurts.

This paper will probably gives you a rough idea - http://onlinelibrary.wiley.com/doi/10.1002/(SICI)1097-0010(199801)76:1%3C10::AID-JSFA928%3E3.0.CO;2-%23/abstract

Abstract
"Defatted milk was ultrafiltered–diafiltered in a 20 kDa polysulphone flat membranes UF unit to obtain concentrated milk with different protein/lactose ratios. Different samples of concentrated–diafiltrated milks with protein concentration between 4•7% and 8•9% and lactose concentration between 2•7 and 0•8% (protein/lactose ratios between 1•7 and 9•5) were fermented (Lactobacillus bulgaricus and Streptococcus thermophilus) to obtain yoghurt-like products. Firmness of the coagulum as well as pH, colony count and organoleptic test were considered in the final products. Concentrated-diafiltrated milk with lactose and protein contents lower than 2% and 6•5%, respectively, lead to a very liquid product. Enriched protein low-lactose fermented milks can be obtained by this technology."

Note: ‘Defatted milk’ is skim milk.
doogles
Member
 
Posts: 755
Joined: 11 Apr 2009
vivian maxine liked this post


Re: Diafiltered Skim Milk?

Postby vivian maxine on December 28th, 2016, 4:53 am 

Thank you, doogles. So it isn't the dry skim milk that I know. It's still a liquid. Interesting about the low protein and lactose. They must have added it back for the nutrition drinks as mine has 15 gms of protein. The ingredients say it is a protein concentrate.

I do appreciate your help. I've been wanting to know what diafiltered meant for a long while. Also glad to know about the prefix.
vivian maxine
Resident Member
 
Posts: 2591
Joined: 01 Aug 2014


Re: Diafiltered Skim Milk?

Postby doogles on December 28th, 2016, 7:07 am 

Yes

I gather that the method controls in advance the concentrations of proteins and lactose they wish to use for the various products. By varying the filter membranes, they can produce almost any combination of proteins and lactose they require.

The dairy factories now use high degrees of technology.

I was amazed in the 1950s when I worked for a cheese and butter factory, that they had a machine called a 'Vacreator'. They could run cream that was becoming sour through it at a temperature of 40 degrees Centigrade and under a high vacuum and it would come out the other end looking and tasting like fresh cream.
doogles
Member
 
Posts: 755
Joined: 11 Apr 2009


Re: Diafiltered Skim Milk?

Postby vivian maxine on December 28th, 2016, 7:17 am 

All of that nice, sweet, fresh cream wasn't?
vivian maxine
Resident Member
 
Posts: 2591
Joined: 01 Aug 2014


Re: Diafiltered Skim Milk?

Postby Braininvat on December 28th, 2016, 1:09 pm 

Many protein drinks just add extra whey protein, as they try to serve up something that fits with the current myth/fad about high protein intake. Massive numbers of studies support the WHO standards of something like 45-55 grams of protein per day as plenty (more is not better, as it just taxes your kidneys because the body can't store extra protein), which means that Americans are already getting 50-100% more protein than they need. The only people who need significantly more protein are pregnant women, trauma victims in recovery, and those who do heavy anaerobic weight training to bulk up. (and that last, as former California governor Schwarzenegger can attest, just gets you a heart attack in your 50's....)
User avatar
Braininvat
Forum Administrator
 
Posts: 4819
Joined: 21 Jan 2014
Location: Black Hills


Re: Diafiltered Skim Milk?

Postby vivian maxine on December 28th, 2016, 1:21 pm 

All you say is true, Biv, but this is one of their specials for diabetics. Very low carbs. That 15 grams may be just about all the protein I get. Not quite but close. Also suits vegetarians, although that wasn't their plan. It copies Boost but in different amounts based on special needs.
vivian maxine
Resident Member
 
Posts: 2591
Joined: 01 Aug 2014


Re: Diafiltered Skim Milk?

Postby doogles on December 29th, 2016, 5:47 am 

This thread brings back old memories vm.

I think we were fairly safe with the cream that we purchased pre 1950s because the fresh milk and cream were obtained from farms and processing plants close to suburban developments. So you can rest easy.

Those Vacreators were used in butter factories to 'purify' cream purchased from farms in relatively remote areas. I recalled times in the 1940s when I stayed at a dairy farm about 50 miles from the factory. A truck visited twice a week and collected the cream from a timber platform erected on the roadside outside the farm. The farmers had to centrifuge their own milk, usually feeding the skim milk to pigs as a by-product. In this particular case, the truck also delivered some grocery supplies and a weekly newspaper. They were magical days for me in my early teens.

This cream was not refrigerated and spent the 3 or 4 days at air temperatures before collection.

The farms closer to the Butter Factories needed only a horse and cart to transfer their cans of cream to the stand on the roadside near to their farm frontages. The 1940s one I stayed at used a draught horse and sled. In the 1950s it wasn't uncommon for me to have to get out of the car to undo three or more wire panels and lay them on the ground before I could pass through and get to the dairy to examine cows. They couldn't afford gates. In wet weather, the tracks were good enough for the horse and cart, but not for my car. On many occasions I had to load up my pockets and arms with everything I thought I might need to treat cows I was called to see and walk to the milking parlour.

Flat tray trucks were used to collect the 10 gallon cans, replacing them with clean empties.

I'll leave it to your imaginations as to the quality of the cream before it went through the Vacreators before being converted into butter.

In the 1960s, things changed in that the Butter Factories began to buy whole milk that had to be stored in refrigerated vats; tankers were used to collect the milk and all-weather tracks with cattle grids rather than gates had to be installed by farmers for the tankers.

I must apologise for being loquacious, but I can't resists telling you about one scam amongst the locals. When the tanker backed up to these more modern dairy farms the driver had to measure the volume of milk in the refrigerated vat, switch on the stirrer, and take a mixed sample of the milk for later analysis of butterfat percentage. He usually placed this sample on the front seat of his truck before labelling it and then went back to the refrigerated vat to couple-up the hose to pump the milk into his bulk tanker.

This sample from each farm was analysed at the factory for butterfat content and the farmer paid accordingly.

One particular farm troubled the factory because the daily percentage of butterfat in the sample varied markedly from day to day. The local police were notified. We had one meticulous detective who was very conscientious and believed in getting first hand evidence on all matters. So he arranged to meet the tanker driver one morning and followed him in his car, stopping a reasonable distance from the farm so that he could make his way undetected to the site.

Just as the son was leaning into the cab of the truck and using a water pistol to squirt some cream into the sample on the front seat while his father was talking to the driver connecting up to the refrigerated vat, the son shit himself as he received a tap on the shoulder from the detective asking him exactly what he was doing.

The story came out that the father and son alternated using a syringe or a water pistol to top up the sample with cream while the other distracted the driver.

I suppose the message is that no matter what field of endeavour any of us work in, there'll always be someone trying to scam the system.

You triggered humorous old memories Vivian Maxine. Thank you.

Apologies for the anecdote, but all the memories came back
doogles
Member
 
Posts: 755
Joined: 11 Apr 2009


Re: Diafiltered Skim Milk?

Postby vivian maxine on December 29th, 2016, 8:18 am 

As did yours, doogles. And, yes, farmers were caught adding water to the milk before the truck came to pick it up.
l
We could get raw milk back then. I grew up on raw milk. Very chancy thing to drink. I ended up with brucellosis. Not real sure what causes that but has something to do with infected cows. We had our own cows; so, no one else's fault.

What I really loved and do not think you can get anywhere now was clabbered milk. Remove the cream to make butter and then let the skimmed milk sour. What you got - as you may know - is large clumps of sour milk and lots of watery liquid around it. It tasted much like today's plain yogurt. Not the same consistency, of course, but tasty. Not everyone liked it. I did. I have heard it was deliberately soured and fed to the hogs. Do not know if that is true. We drank ours.

We also made our own buttermilk. No idea how that was done but it was much better than what we buy today.

Then, of course, came all the changes. Pasteurization came first. Dairy producers had to pasteurize milk before bottling and selling. You can still find the occasional dairy farmer selling raw milk today but under much more stringent regulations. We have one here in this county. And - wonder of wonders - he still delivers his milk to your home if you want. No doubt costs extra.

Delivered milk to you door? Temperature far below freezing, milk delivered 1t 3:00 or 4:00 AM. You get up a couple of hours later and find a bottle with a tower of frozen milk standing out the top. People had small milk boxes where where the milk man put the bottles.

Many changes. Homogenization so you can no longer take the cream off the top and make butter. Plus, it has become very hard to buy real whipping cream. Long story there, too.

Better stop. Getting slow here. "Thanks for the memories" Viv
vivian maxine
Resident Member
 
Posts: 2591
Joined: 01 Aug 2014



Return to Chemistry

Who is online

Users browsing this forum: No registered users and 2 guests