INFORM October 2024

inform October 2024, Vol. 35 (9) • 11

THE LARGEST CHALLENGE LOOMING ABOVE ALL FOR OLEOSOMES IN THE FOOD INDUSTRY: THE TASTE. KEEPING THEIR TASTES CONSISTENT IS A PROBLEM SINCE DIFFERENT SOURCES OFFER DIFFERENT TASTES.

percent protein, non-ideal for current oleosome-based food applications. Safflower makes a higher fat product but tastes bad and is best left for personal care applications. With canola Botaneco says they are working on process improvements to optimize co-extraction of oilbodies and protein isolates. The sunflower process is well developed at Botaneco and is the best overall oilbody source for both neutral taste, cost effec tiveness, and application benefits, says Hargreaves. LOOMING OBSTACLES There are still a variety of technical challenges to overcome for oleosomes to gain prominence in the food ingredient mar ket. To start, aqueous extractions tend to produce unwanted interactions that can destabilize intact oleosomes, according to Simone Bleibach Alpiger, a food science researcher assistant at Aarhus University in Demark, who studies oleosomes. Extracting intact oleosomes is a balancing act, says Alpiger. “They are colloidally unstable, that is the main chal lenge,” she said. That is to say that while the oleosomes them selves may remain intact, under certain chemical conditions they might form large flocculates with other coextracted components, changing their colloidal stability. At lower pHs, towards the isoelectric point of oleosins, the proteins start to aggregate. Adding a pectinase, an enzyme that breaks down co-extracted soluble fibers, intensifies the aggregation. “If you have mixed flocculates, it could potentially be suitable for a spread or other food product where an emul sion-filled gel structure is desired,” said Alpiger. But, she adds, this is generally not preferable. At higher pH there is less aggregation, but then producers need to lower the pH back down to make it palatable for food, otherwise the product would be bitter. Previous research has shown that depending on the extraction conditions, phospho lipids will migrate from the oleosome membrane. Given this observation, when used in food applications they could frac tionate and break an emulsion, forming a cream that rises to the top. Alpiger says this phospholipid behavior needs to be studied further. Another challenge is the natural paradox. “Oleosomes are natural and you do not want to manipulate them too much,” Plankensteiner says. But sometimes manipulation is necessary. Oleosomes with a diameter above 1µm have a greater tendency to form a cream layer. Oleosome diameters vary from one plant to another and even within each plant— canola oleosomes range from 0.2µm to 20µm (https://doi. org/10.1016/j.foodhyd.2021.107078). This can give an advan tage to certain sources, says Plankensteiner. Soybeans, for instance, tend to produce small diameter oleosomes of around 0.5μm. “You can change the size of oleosomes—like through homogenization—but that is an additional processing step making the production more energy intensive,” he says. Then there is the challenge of economics. Traditional oil extraction from a plant like canola is well-established technol ogy that yields upwards of 95 percent. For the past few years, extracting oleosomes from the same plants has only achieved yields around 60 percent (https://doi.org/10.1016/j.jfood -

eng.2019.109890). This might be changing soon, however, with other plant sources. Scientists have reported yields of nearly 90 percent (https://doi.org/10.1016/j.foodhyd.2022.108419). Still, the largest challenge looming above all for oleosomes in the food industry: the taste. Keeping their tastes consis tent is a problem since different sources offer different tastes. Soybean oleosomes reportedly have a bean-y flavor, where canola is a bit nutty. Since canola is a Brassica species, it tends to taste sulfurous and mustard-y, but further processing tones down the flavor if desired. “Some oleosomes have a lingering mouthfeel and can be a bit astringent,” said Plankensteiner. This could be due to phe nolic compounds, not present in oleosomes but in the seeds that co-extract from the plants. However, he is hopeful that Plankensteiner, is using them to help reframe dairy-free prod ucts for consumers. “We need to convince the consumer to not just want a replicate for milk, but to start enjoying the specific flavors from oleosome-containing products,” he said. Considering everything that we make from milk, like cheese or cream, replicating all those products would be challenging. Oleosome-containing alternatives would simply be a different product from what they imitate. Plankensteiner says that is the advantage of oleosomes and dairy-free products generally, the opportunity to cre ate something entirely new. Instead of producing a neutral flavored product that imitates dairy milk, he says, we should explore options like oleosomes from roasted hazelnuts. There are many possibilities. “It is not just a replacement for milk but an additional product, an attractive product due to its own properties,” says Plankensteiner. “That is what moves us forward.” Dan Samorodnitsky is a science journalist based in Minneapolis. He is the co-founder of Sequencer Magazine , where he covers biology, health, genetics, and other science stories. flavor issues can be resolved. THE PATH FORWARD The real opportunity for oleosomes, according to