If you’ve visited a trendy café in recent years, you may have noticed ‘golden’ turmeric milk on the menu. Although recently advertised as a caffeine-free, healthy coffee alternative, the drink is a fantasy version of haldi doodh – a traditional Indian drink often used as a home cold remedy. And now, researchers have developed an efficient method to create a plant-based, instant version that retains the beneficial properties of the ingredients while extending shelf life.
The researchers will present their results at the fall meeting of the American Chemical Society (ACS).
Golden milk – also called golden or turmeric latte – consists of milk, turmeric and spices, and is a good option for people who want to avoid caffeine or coffee or perhaps enjoy a unique taste. “It’s a very good drink, especially when it’s cold outside or you’re sick,” explains Anthony Suryamiharja, a graduate student at the University of Georgia who presented the research at the meeting. He says turmeric also contains the bioactive compound curcumin – a polyphenol that has been studied for its potential anti-inflammatory and antioxidant effects. “If we can incorporate bioactive compounds like curcumin into plant-based milks to bring them to the same nutritional level as cow’s milk, why not?” Suryamiharja asks.
However, curcumin is difficult to separate from turmeric, usually requiring complicated extraction techniques involving organic solvents, several days and a lot of energy. Additionally, the compound tends to break down over time, shortening its shelf life. Inspired by golden milk, Suryamiharja, Hualu Zhou and colleagues wanted to investigate whether there was a way to extract and store curcumin from plant-based milk.
They first added turmeric powder to an alkaline solution, where the high pH made the curcumin more soluble and easier to extract than in plain water. This deep red solution was then added to a sample of soy milk, turning it a dark yellow color. They brought it back to a neutral pH around 7. Like low pH acids, high pH bases are not the most pleasant to consume. The neutralized pseudo-golden milk could be consumed as is, but to further preserve it, the team removed the water from the solution through freeze-drying, which instantly created a golden milk powder.
This method not only extracts curcumin from turmeric more efficiently than existing methods, but also encapsulates the curcumin in oil droplets in the soy milk. This means that when consumed, our bodies recognize the curcumin as fat and digest it as such, theoretically making the curcumin more bioavailable, or likely absorbed and able to have an effect in the body. Encapsulating the curcumin also protects it from air and water, giving it a longer shelf life.
Although this work focused specifically on soy milk due to its high amino acid content, the researchers say it can be applied to other plant-based milks, providing options for people with a soy allergy. Furthermore, their pH-driven extraction method could be used on various plant compounds with similar ease and efficiency. Blueberries, for example, are rich in anthocyanins, another water-soluble polyphenol. “If we use the same method, we can extract the polyphenols in about a minute,” Zhou explains. “We want to try to use it to upcycle byproducts and reduce food waste from fruit and vegetable growing here in Georgia.”
Although more research is needed before their instant golden milk hits store shelves, the researchers’ initial results are promising: Suryamiharja reports that the milk tasted good, despite not enjoying golden lattes all that often himself.
The team hopes that this work can help explain the chemistry behind what may seem like nothing more than a simple drink, and that it can improve the nutritional value and convenience of that drink for those who enjoy it. Suryamiharja explains that “people usually do a lot of simple things in the kitchen, but they don’t really realize that there is a chemistry behind it. That’s why we try to explain those unspoken things in a simple way.”
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