Milk time capsule in Antarctica provides valuable insights into dairy’s evolution

02 Apr 2024 --- A preserved sample of whole milk powder (WMP) manufactured in New Zealand in 1907 and exported to Antarctica via a British expedition led by Ernest Shackleton recently underwent scientific analysis by researchers of the Fonterra Research and Development Centre. This has provided valuable insights into the properties of dairy that have endured and how it has evolved in just over a century.

One remaining container of WMP from the Defiance brand was uncovered at Shackelton’s base camp during the Antarctic Heritage Trust restoration project, which has made the research possible. The powder was stored at ambient conditions to ensure that any damaging reactions in the WMP were significantly retarded.

“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,” says Dr. Skelte Anema, lead investigator and principal research scientist with the Fonterra Research and Development Centre in New Zealand.

“Before we had vacuum-assisted evaporation, milk powders in the early twentieth century were manufactured by a roller-drying process involving boiling-hot milk being poured between two steam-heated revolving cylinders so that the water evaporated, leaving a thin sheet of dried milk that would have been milled and sieved.”

Building blocks of nutrition
The findings of the comparative study published in the Journal of Dairy Science show that the milk produced these days shares many similarities to that produced in the 20th century despite advancements in selective breeding and changes to farm practices.

An interdisciplinary research team at Fonterra Research and Development Centre and members of the Antarctic Heritage Trust analyzed a few hundred grams of Defiance milk. They compared it with two modern-day commercial, spray-dried WMP samples from Fonterra. 

The samples were analyzed using scanning electron microscopy and typical micrographs. Transmission electron microscopy allowed the protein material in the milk powder samples to be studied at high magnification, facilitating visualization of the casein micelle structure.

They compared the samples’ primary component composition, major and trace mineral composition, protein composition, fatty acid composition, phospholipid composition, microstructural properties, color analysis and volatile component analysis. The proteins in the Shackleton WMP were more lactosylated than in the spray-dried powders. 

The Shackleton WMP had a higher ratio of κ-casein and a higher ratio of β-lactoglobulin than the spray-dried powders. The αS1-casein, β-casein, αS2-casein and α-lactalbumin protein variants were similar in all powders.(A) The tin-plated can of Defiance brand dried milk found in Shackleton’s Cape Royds base camp hut, with a close-up label in (C) (Credit: Antarctic Heritage Trust, New Zealand). (B) is of the Joseph Nathan & Sons Bunnythorpe Defiance Dried Milk Factory circa 1904 (Credit: Massey University, New Zealand). 

“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,” says Anema.

The fatty acid, phospholipid and protein composition, including casein and whey protein genetic variations, are “remarkably similar.” The principal mineral components were also alike between samples, except for high levels of lead, tin, iron and other trace minerals found in the Shackleton WMP, most likely from the tin-plated storage can or water supply.

“These issues have been essentially eliminated from modern milk powders through the use of stainless steel and quality water services,” explains Anema. Another notable difference was the presence of oxidation-related volatile aroma compounds in the Shackleton samples. 

“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.” Modern spray-dried WMPs are superior in powder quality, specifically in appearance and quickly dissolved. 

“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,” Anema notes.

British Antarctic expedition
Shackleton’s British Antarctic Expedition aboard the ship Nimrod set sail from Lyttelton, New Zealand, on New Year’s Day 1908 with the mission to be the first to set foot on the South Pole. 

The ship was packed with dairy — 1,000 pounds (454 kg) of dried whole milk powder, 192 pounds (87 kilograms) of butter, and two cases of cheese. Shackleton and his crew came within 100 nautical miles of the South Pole, further than anyone before them and set up a base camp.

The recent discovery of the ship Endurance, three km under the ice at the bottom of the Weddell Sea in Antarctica, has reignited interest in Sir Ernest Shackleton and his ill-fated Imperial Trans-Antarctic expedition). The ship was trapped in the ice in 1915 and sank. 

Shackleton and five crew members survived on the ice and sailed in lifeboats to reach Elephant Island in 1916, then climbed the mountains to reach the whaling station at Stromness. The remaining crew was rescued in August 1916. The whole ordeal is documented in books by Shackleton.

In 2002, the Antarctic Heritage Trust launched the Ross Sea Heritage Restoration project to preserve four significant Antarctic huts and their extensive artifact collections. According to the researchers, the results of the present study underscore the fact that dairy products are essential for human nutrition.

Meanwhile, Nutrition Insight sat down with Fonterra to discuss the evolving dairy space. The infant nutrition market is expanding, and consumers increasingly demand ingredients that feature holistic and gut health products with functional and fortifying ingredients. At the same time, technological advances are enhancing the nutritional value, texture, flavor and variety of traditional ingredients.

The company highlights that China is a critical market for infant nutrition because of its substantial infant formula market size. Coupled with the implementation of stricter product regulation, the country fosters increased market differentiation and creates numerous prospects for brands to introduce innovative and novel products.

By Inga de Jong