|Milk Types||Greenhouse Gas Emissions (kg CO2-Ceq per 200 g)|
Oat milk is a type of plant milk derived from whole oat (Avena spp.) grains by extracting the plant material with water. Oat milk has a creamy texture and a characteristically oatmeal-like flavor, though it is sold commercially in various flavor-varieties such as sweetened, unsweetened, vanilla, and chocolate. Unlike other plant milks, whose origins date as early as the 13th century, oat milk is a modern creation, developed by the Swedish scientist Rickard Oste in the early 1990s.
Soy milk predates all other alternative milks, including oat milk, both as a cultural and commercial product. Within the past hundred years, soy milk made its way from Asia to European and American grocery stores, initially as a dairy substitute due to lactose intolerance. The increase in consumption of soy milk since its global distribution created a large market for plant-based, non-dairy milks like oat milk. The first example of an oat-based plant beverage was in the early 1990s, when Rickard Oste developed oat milk. Oste was working as a food scientist at Lund University in Lund, Sweden, researching lactose intolerance and sustainable food systems, when he invented the drink. Soon after, Oste founded Oatly, the first commercial manufacturer of oat milk.
The pioneer in commercial oat milk, Oatly, has its products in 3,500 coffee shops and 1,000 grocery stores across the United States, but is not the only prominent oat milk producer. Oat milk can be found under brand names Oatly (Sweden), Pureharvest (Australia), Alpro (UK), Bioavena (Italy), Simpli (Finland), Vitasoy (Hong Kong), and Pacific (USA), among others. In 2018, global sales of plant milks, including oat milk, were US$ 1.6 billion, with a forecast of $41 billion by 2025.
The production of oat milk is similar to that of most other plant milks. Cereal grains like oats are indigestible when unprocessed due to their hard, outer hull, so processing is necessary to create a product with nutrients which are bioavailable. The procedure starts by grinding, or milling, oats to break apart their outer hull.
Soaking and subsequently extracting nutrients from the oats have the most direct implications on the final milk product. Increasing the yield in this step may be assisted by chemical catalysts, enzymes, or an increase in temperature, all in order to remove nutrient molecules from the solid byproduct and incorporate them into the liquid. Chemical catalysts increase the pH of the mixture, enzymatic catalysts induce partial hydrolysis of proteins and polysaccharides, and higher temperatures increase reaction rates. Separating the liquid from the solid byproduct is a simple step achieved through filtration, decanting, or centrifugation.
Once the liquid product is isolated, adding other ingredients, such as fortifying vitamins and minerals, or sweeteners, flavorings, salts, oils, and similar, formulates the final product. Oat milk is naturally lower in calcium, iron, and vitamin A than dairy milk, so the addition of these nutrients is necessary in order for the product to be a direct nutritional substitute of dairy milk. Homogenization and heat-treatments such as pasteurization or ultra-high temperature (UHT) treatments are used to extend the product's shelf life.
Challenges to processing
Because oat milk is produced by the disintegration of plant materials, the resulting particle sizes are not as uniform as bovine milk. This variation in particle size is due to the vastly different lipid and protein molecules. Decreasing particle size, improving particle solubility, and using hydrocolloids and emulsifiers are common ways to improve product quality via homogenization.
Another problem posed by the natural composition of oats is their high starch content. The starch content (50–60%) is challenging during UHT treatments because of starch's relatively low gelatinization temperature. To overcome this, producers use an enzymatic hydrolysis of starch by alpha- and beta-amylase, producing maltodextrins which gelatinize at higher, more suitable temperatures.
Adding ingredients as fortifying nutrients is also a difficult procedure. The nutrients must be bioavailable and stable in the final product, otherwise the quality or effectiveness of the product may be insufficient. Research is often funded to discover procedures which successfully incorporate bioavailable nutrients into oat and other plant-based milks.
|Nutritional content of cow, soy, almond and oat milks|
|Cow milk (whole, vitamin D added)||Soy milk (unsweetened; calcium, vitamins A and D added)||Almond milk (unsweetened)||Oat milk (unsweetened)|
|Calories (cup, 243g)||149||80||39||120|
|Saturated fat (g)||4.55||0.5||0||0.5|
|Vitamin B12 (µg)||1.10||2.70||0||1.2|
|Vitamin A (IU)||395||503||372||267|
|Vitamin D (IU)||124||119||110||144|
In comparison to cow's milk, oat milk is similar in total calories per liquid volume (per cup serving, 120 vs 149 calories for cow's milk), has half the protein content, somewhat less total fat, but only about 1/10 the content of saturated fat, and about 1 1/2 times the total carbohydrate (although simple sugars are half that of cow's milk). Cow's milk has no fiber, but oat milk has 2 g fiber per serving. Calcium and potassium contents are comparable. See the article Plant milk for details.
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