Lab-grown fat could give cultured meat real flavor and texture

Researchers have successfully bulk-produced fat tissue in the lab that has a similar texture and make-up to naturally occurring fats from animals.

The results, described in a study published today in eLife, could be applied to the production of cultured meat grown entirely from cells, giving it a more realistic texture and flavour.

Cultivated meat has been making waves in the news lately, with reports from startup companies around the world developing cell-grown chicken, beef, pork and fish -- mostly in early stages of development, not ready for large-scale production and with a couple of exceptions, not yet approved for commercial sale. Most of those products in development are in the form of an unstructured mixture of cells -- like chicken nuggets rather than a slice of chicken breast. What is lacking is the texture of real meat, created by muscle fibres, connective tissue and fat -- and it's the fat that gives meat flavour.

In fact, consumer testing with natural beef of different fat content showed that the highest scores were registered for beef containing 36% fat.

However, producing cultured fat tissue in sufficient quantities has been a major challenge because, as the fat grows into a mass, the cells in the middle become starved of oxygen and nutrients. In nature, blood vessels and capillaries deliver oxygen and nutrients throughout the tissue. Researchers still have no way to replicate that vascular network at a large scale in lab grown tissue, so they can only grow muscle or fat to a few millimetres in size.

To get around this limitation, the researchers grew fat cells from mice and pigs first in a flat, two-dimensional layer, then harvested those cells and aggregated them into a three-dimensional mass with a binder such as alginate and mTG, which are both already used in some foods.

"Our goal was to develop a relatively simple method of producing bulk fat. Since fat tissue is predominantly cells with few other structural components, we thought that aggregating the cells after growth would be sufficient to reproduce the taste, nutrition and texture profile of natural animal fat," says first author John Yuen Jr, a graduate student at the Tufts University Center for Cellular Architecture (TUCCA), Massachusetts, US. "This can work when creating the tissue solely for food, since there's no requirement to keep the cells alive once we gather the fat in bulk."

The aggregated fat cells immediately had the appearance of fat tissue, but to see if they truly reproduced the features of native fat from animals, the team carried out a series of further experiments.

First, they explored the texture, by compressing the fat tissue and seeing how much pressure it could withstand compared to natural animal fat. They found that cell-grown fat bound with sodium alginate was able to withstand a similar amount of pressure to fat from livestock and poultry, but the cell-grown fat that was bound with mTG behaved more like rendered fat -- similar to lard or tallow. This suggests it could be possible to fine-tune the texture of cultured fat, so it best resembles the real-life texture of fat within meat, using different types and amounts of binders.

Cooking releases hundreds of compounds that add flavour to the meat, and most of those compounds originate from fat, including lipids and their component fatty acids. The team therefore examined the composition of molecules from the cell-grown fat and found that the mix of fatty acids from cultured mouse fat differed from native mouse fat. However, the cultured pig fat had a much closer fatty acid profile to the native tissue. The team's preliminary research suggests it might be possible to supplement growing fat cells with the required lipids to ensure that they more closely match the composition of natural meat.

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Cans or bottles: What's better for a fresh, stable beer?

The flavor of beer begins to change as soon as it's packaged, prompting a debate among afficionados: Does the beverage stay fresher in a bottle or a can? Now, researchers report in ACS Food Science & Technology that the answer is, well, complicated, and depends on the type of beer. An amber ale stayed fresher in bottles, whereas container choice made much less difference to the stability of an India Pale Ale (IPA).

In addition to water and ethanol, beer contains thousands of flavor compounds, which are metabolites produced by yeast, hops and other ingredients. During storage, chemical reactions break down some of those components while forming others. This reduces the content of some tasty flavors while generating unappetizing ones, contributing to the aging, or staling, of beer. To help brewers prolong shelf life, researchers have studied beer aging, but they've concentrated on light lagers and a limited group of chemicals. Jessica Prenni and colleagues wanted to extend that work to amber ale and IPA, as well as additional compounds. The team also wanted to conduct the first stability comparison of beer packaged in glass bottles versus aluminum cans.

Cans and brown bottles of amber ale and IPA were chilled for a month and then kept at room temperature for five months to mimic typical storage conditions. Every two weeks, the researchers analyzed the metabolites in newly opened containers. Throughout this time, the concentration of certain metabolites in amber ale -- including some amino acids and esters -- differed significantly depending on whether it was packaged in a bottle or can. IPA, however, was much less sensitive to packaging type, possibly because of its higher concentration of polyphenols from hops. These compounds not only prevent oxidation but also bind to amino acids, thus retaining them in the beer rather than allowing them to get stuck to the inside of a container.

The researchers also found that the metabolic profile of both amber ale and IPA changed over time, whether packaged in a can or bottle. However, amber ale in cans showed the greatest variation during aging. Once scientists find out how all of these changes affect flavor, brewers will be able to make more-informed decisions about the best type of packaging for their particular type of beer.

From Science Daily

Like wine, environmental conditions impact flavor of whiskey, study finds

 Flavor differences in whiskey can be discerned based solely on the environment in which the barley used to make the whiskey is grown, a new study co-authored by an Oregon State University researcher found.

This is first scientific study that found the environmental conditions, or terroir, of where the barley is grown impacts the flavor of whiskey, said Dustin Herb, an author of the study and a courtesy faculty member in the Department of Crop and Soil Science at Oregon State University.

"Terroir is increasingly being used to differentiate and market agricultural products, most commonly wine, as consumers grow more interested in the origins of their food," Herb said. "Understanding terroir is something that involves a lot of research, a lot of time and a lot of dedication. Our research shows that environmental conditions in which the barley is grown have a significant impact."

Herb, who is originally from Lebanon, Oregon, and earned his undergraduate and doctoral degrees from Oregon State, is the only American author of the study, which was published in the journal Foods. The other authors are all from Ireland, where the study was conducted.

Herb's doctoral research at Oregon State with Pat Hayes, a barley breeder in the College of Agricultural Sciences, focused on the contributions of barley to beer flavor. Their research found notable differences in the taste of beers malted from barley varieties reputed to have flavor qualities.

That research caught the attention of Waterford Distillery. The Irish distillery reached out to Herb, flew him to Ireland and asked him if he could design a study that would attempt to answer the question of whether terroir exists in whiskey. They dubbed it The Whisky Terroir Project. (Whiskey can be spelled with and without an "e.")

Herb designed a study that involved planting two common commercial varieties of barley in Ireland -- Olympus and Laureate -- in two distinct environments: Athy, Co. Kildare and Buncloudy, Co. Wexford in 2017 and 2018. Athy is an inland site and Buncloudy is a coastal site. They were selected in part because they have different soil types and different temperature ranges and rainfall levels during the barley growing season.

The crops of each barley variety at each site in each year were harvested, stored, malted and distilled in a standardized way. Once distilled, the product is called "new make spirit." (It isn't called whiskey until it is matured in a wooden cask for at least three years.)

The researchers used gas chromatography mass spectrometry and the noses of a six-person trained sensory panel to determine which compounds in the barley most contributed to the aroma of the new make spirit.

That analysis, along with further mathematical and statistical analysis, found that the environment in which the barley was grown had a greater contribution to the aroma of the whiskey than the variety of the barley. That was the clear indication of the impact terroir has on the new make spirit.

Furthermore, the sensory analysis found distinct differences in the aroma characteristics of the new make spirit from the barley grown in each location. In Athy, it was more positively associated with sweet, cereal/grainy, feinty/earthy, oily finish, soapy, sour, stale and mouldy sensory attributes and in Bunclody it was more associated with dried fruit and solventy attributes.

"What this does is actually make the farmer and the producer come to the forefront of the product," Herb said. "It gets to the point where we might have more choices and it might provide an opportunity for a smaller brewer or a smaller distiller or a smaller baker to capitalize on their terroir, like we see in the wine industry with a Napa Valley wine, or Willamette Valley wine or a French Bordeaux."

The sensory analysis also found differences in the aromatic profiles between the 2017 and 2018 seasons that were studied.

"This makes us think there might be a vintage aspect to the whiskey like wine, where you buy a 2019 or a 2020 or a 2016," Herb said. "Could the whiskey industry operate in a similar way, where someone is going to seek out a certain vintage of a certain year?"

To answer that question, more research needs to be done, Herb said. That is a project the Whisky Terroir Project plans to tackle: examining flavor changes in the spirits as they mature in casks and to see what happens with the terroir impact.

The team is also scaling up the research to study terroir in commercial-scale barley fields over a five-year period.

In addition to Herb, who also works full-time as a plant breeder at Albany, Oregon-based OreGro, which develops turf and forage products, other authors of the paper are: Maria Kyraleou and Kieran Kilcawley of the Teagasc Food Research Park; Grace O'Reilly and Neil Conway of Waterford Distillery; and Tom Bryan of Boormalt.

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