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Japanese cuisine wouldn’t be the same without miso — but astronauts wanting to use the fermented soybean staple in space one day might have to get used to a difference in taste.
An experiment on board the International Space Station (ISS) has produced miso paste, thought to be the first food deliberately fermented outside Earth — a feat that scientists hope will shed light on the potential for life to exist in space, and broaden the culinary options for astronauts.
The “space miso” had a similar umami, or savoriness, to miso made on Earth. But according to the researchers who sampled it, there was a key difference: a stronger roasted and nutty flavor.
Scientists Maggie Coblentz from the Massachusetts Institute of Technology (MIT) and Joshua Evans from the Technical University of Denmark sent a small container of cooked soybean paste to the ISS in March 2020, where it was left to ferment for 30 days before returning to Earth as miso.
The miso was kept in a container with sensors, which closely monitored temperature, relative humidity, pressure, and radiation, according to the peer-reviewed paper released in the journal iScience on Wednesday.
As part of the experiment, two other miso batches were fermented on Earth for comparison — one in Cambridge, Massachusetts in the US and the other in Copenhagen, Denmark.
“We didn’t know what to expect — fermentation had never been done before in space,” Evans, the co-lead author of the study, told CNN.
“The space miso one was darker and clearly more jostled—which makes sense, as it had traveled much more than either of the earth misos. It was exciting to smell and taste the first bite.”
He explained some environmental features in space, in particular microgravity and increased radiation, could have impacted how microbes grow and metabolize, and in turn how fermentation works.
“By bringing together microbiology, flavor chemistry, sensory science, and larger social and cultural considerations, our study opens up new directions to explore how life changes when it travels to new environments like space,” Evans said.
Furthermore, Evans said the research could “enhance astronaut well-being and performance,” and “invite new forms of culinary expression, expanding and diversifying culinary and cultural representation in space exploration as the field grows.”
Miso, the salty fermented bean paste, forms the base of many soups, sauces and marinades. Every region in Japan has its own special recipe.
It is traditionally made of soaked soybeans, water, salt and koji (a type of mold), and traditionally takes about six months to develop its distinct umami taste, with the flavors intensifying the longer it ferments.
Many fermented foods contain probiotics, live microorganisms that, when ingested, can work in conjunction with the existing good bacteria in the gut microbiome to help regulate the digestive system.
But Evans said the further analyses is still need to asses its nutritional value, including the macromolecular composition and bioactive compounds present in the space miso.
Coblentz, also a co-lead author of the study, said the miso fermentation on the ISS underlined “the potential for life to exist in space” by showing how a microbial community could thrive.
Scientists have long experimented with growing and harvesting fresh produce in space, including various types of lettuce and radishes. In 2021, the ISS even hosted a taco party to celebrate the harvest of the first chile peppers in space.
One Japanese company is also making a special brew of sake fermented in space. Asahi Shuzo, the company behind the popular Dassai brand, has paid Japan Aerospace Exploration Agency for access to the Kibo experiment module, part of the ISS, to conduct tests.
The company is also developing space brewing equipment, with a planned launch date later in 2025.