As dairy alternatives such as almond, oat, and soy milk continue to grow in popularity, an centuries old question regarding cow’s milk still remains. How does today’s dairy differ from what previous generations consumed?
Some clues are now emerging in the form of some 117-year-old whole milk powder that was transported on Sir Ernest Shackleton’s British Antarctic Expedition in the early 20th Century. A study published in the March 2024 issue of the Journal of Dairy Science found that despite advancement in selective cow breeding and changes to farm practices, milk from the present and past have more similarities than differences.
The Nimrod expedition
The powdered milk in the study was made by New Zealand’s Defiance brand in 1907. On New Year’s Day in 1908, Shackleton and his crew aboard the ship Nimrod set sail on a quest to be the first to set foot on the South Pole. The Nimrod was well stocked with dairy, including 1,000 pounds of dried whole milk powder, 192 pounds of butter, and two cases of cheese. The crew would make it farther south than any known human had been before and made it within 100 nautical miles of the South Pole and left their base camp and its supplies behind.
The photo on the top left (A) shows the tin-plated can of Defiance brand dried milk found in Shackleton’s Cape Royds base camp hut, with a close-up label in the bottom photo (C) (courtesy of the Antarctic Heritage Trust, Christchurch, New Zealand). The top-right photo (B) is of the Joseph Nathan & Sons Bunnythorpe Defiance Dried Milk Factory circa 1904 (courtesy of Massey University, Palmerston North, New Zealand).
About a century later, one remaining container of Defiance whole milk powder was uncovered during a restoration project by the Antarctic Heritage Trust restoration project. The milk powder had been frozen in time and ice at Shackelton’s base camp for 100 years.
“The Shackleton dried milk is possibly the best-preserved sample manufactured during the pioneering years of commercial milk powder production, and its discovery gives us a once-in-a-lifetime chance to understand the similarities and differences between a roller-dried milk powder manufactured over 100 years ago with modern spray-dried counterparts,” Skelte G. Anema, a study co-author and chemist at Fonterra Research and Development Centre in New Zealand, said in a statement.
[Related: Ancient milk-drinkers were just fine with their lactose intolerance–until famine struck.]
According to Anema, before vacuum-assisted evaporation, milk powders were made by a roller-drying process. Boiling-hot milk was poured between two steam-heated revolving cylinders so that the water evaporated. A thin sheet of dried milk was left behind that was then milled and sieved. While scientists knew that these early milk powders were not as sophisticated as those available today, they were not sure what other differences existed.
Analyzing milk powders
In the study, the team analyzed a few hundred grams of the 100 plus year-old Defiance milk. They set out to compare it with two modern-day commercial, non-instantized and spray-dried whole milk powder samples. They compared the composition of the milk’s major and trace components, proteins, fatty acids, and phospholipids. They also looked at the microstructural properties, color, and volatile components in the different whole milk powder samples.
“Despite more than a century between the samples, the composition of bulk components and detailed protein, fat, and minor components have not changed drastically in the intervening years,” said Anema.
The fatty acid composition, phospholipid composition, and protein composition of the samples were generally similar. The major mineral components between the samples were also relatively alike, except for higher levels of lead, tin, iron, and other trace minerals found in the Shackleton whole milk powder. These minerals likely came from the tin-plated can the powder was stored in and the equipment and water supply used during that time period. Using stainless steel and better water has eliminated that issue from modern milk powders, according to the team.
Another notable difference in the Shackleton milk samples was the presence of oxidation-related volatile aroma compounds.
[Related: Tending Sir Ernest’s Legacy: An Interview with Alexandra Shackleton.]
“Perhaps from less-than-ideal collection and storage of the raw milk before drying, but it’s much more likely that—even in frozen conditions—being stored in an open tin for a century is going to result in continued oxidation,” said Anema.
Despite the remarkable similarities between the milk samples, the team points out that modern spray-dried whole milk powders are substantially superior in terms of the powder quality. They look better and dissolve in water more easily.
This unique Antarctic time capsule still provides a glimpse into dairy food production methods of the past and its evolution over time.
“The Shackleton samples are a testament to the importance of dairy products—which are rich in protein and energy as well as flexible enough to be powdered for easy transport, preparation, and consumption,” said Anema.
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