Plant-based Yogurt Processing Line

1. The plant-based yogurt can also be called fermented plant-based products. It refers to the plant-based materials(oats, almond, coconut, soybean, cashew nuts, etc.) after grinding into milk, then fermenting milk into yogurt-style products, as the end products are similar in taste, appearance, and texture with traditional dairy yogurt products, so it is also called plant-based yogurt products.
2. As health concerns rise globally and environmental sustainability, pure natural and zero gas emissions foods and drinks are the new trends, the plant-based fermented yogurt products have unparalleled advantages compared to animal dairy yogurt products, and are increasingly available around the world.
3. The plant-based yogurt processing steps are plant-based product grinding, separation, enzyme treatment(mainly for the starch-rich materials such as oats, rice and millets materials), plant-based milk formulation, milk heat treatment, plant-based yogurt fermentation, cooling, buffering and filling, CIP cleaning system for the whole line cleaning.
4. The capacity for plant-based yogurt processing line is from 500L/H to 5000L/H, and the end products can be filled into cups, tubs or bottles.
5. Because of the special characteristics of plant ingredients, such as low sugar content, and heat sensitivity, so when processing plant-based products into yogurt, there are also some challenges: product viscosity after fermentation, heat treatment method and fermentation parameter, these are key factors that can determine whether you can produce the high-quality products.
6. The whole plant-based yogurt processing line is made of SUS304/SUS316L material and equipped with CIP cleaning system, which ensures the hygiene production.

The plant-based yogurt needs a certain viscosity, texture, mouth feel and appearance to attract consumers, while most of the plant-based ingredients do not have enough sugar to ferment into acid to make the end products have good viscosity, so when for formulation, adding suitable sugar and thickeners is a key process for crafting the end products. Here give you a brief introduction of what ingredients need to add when for formulation:

Starch: Natural and modified starch can be added to plant-based products to increase the viscosity of the yogurt. The starch will be dissolved in the high shear emulsifying tank in the base before heat treatment. Some starches will create high viscosity before fermentation, while others will have an effect after cooling in the package.

Pectin and gum: Pectin and gum are often used together in plant-based yogurt-style products to increase viscosity and water-holding capacity (stability), it is the main thickener agent in plant-based yogurt production.

Sugar: Depending on the raw plant material, sucrose, glucose and maltose are commonly added sugars. If the raw material already contains a lot of starch (e.g. oats or rice), the sugar is produced from the starch with an enzymatic process while manufacturing the plant base. The sugar composition can be further controlled by the choice of enzymes. The fermentation culture is often dependent on a specific sugar for its functionality.

Other ingredients: Fats, emulsifiers, flavors and aromas, and fruit particles can also be added to plant-based yogurt products to increase nutrition and flavor.

The plant pretreatment system mainly includes plant ingredients soaking, wet grinding/extracting, filtration, enzymatic treatment(for starch-rich materials such as oats, rice, quinoa, etc.), decanter separation, etc. This process system is making the raw plants into slurry or pulp, and it is the same process when you make plant-based milk products.

For plant-based yogurt production, certain ingredients may require warm mixing, while the addition of oil and specific stabilizers typically demands high-shear mixing to ensure a smooth, homogeneous, and lump-free blend. Therefore, the use of a high-shear mixer, along with a mixing station equipped with heating functionality, is highly recommended.

The ingredients will be added to the plant-based products to formulate certain viscosity and flavor. Different plant-based products need to different ingredients, all the ingredients will be dissolved into the high shear mixing tank.

In oat-based yogurt production, the enzymatic hydrolysis process can decompose the starch into sugar, so less sugar can be added, but as the fats in the oat base are little, so the oil can be dosed.

In soya-based yogurt production, enough sugar needs to add to the soya base, so when fermentation, there is enough starch that can be converted into acid and increase the viscosity of the final products.

In almond yogurt production, due to the low starch/high-fat content in almonds, it also needs to add enough sugar and thickener into the base to achieve viscosity.

When all the ingredients are mixed, then the product base needs to undergo heat treatment. The purpose of the heat treatment is mainly to kill all pathogenic bacteria and swelling of the stabilizer and starch, and denaturation of proteins.

Heat treatment of plant-based milk products is often done by heating the base to 60-65°C, at which temperature the product is homogenised at a pressure of 200 bar or higher, then the product is heated to 90-95 ℃ for heat treatment and sometimes it will also be equipped with one vacuum degasser for air removing the milk.

The heat treatment temperature and holding time strongly depend on what thickeners and stabilizers you use. Some thickeners cannot tolerate high temperatures, while others need a very long holding time to be activated, so when considering the heat treatment, you need to consider both factors: food safety and thickeners’ temperature tolerance. The common heat treatment process for yogurt products is 90-95℃ for 1-10 min, depending on the recipe (primarily depending on what type and amount of starch/thickener is used). With this condition, the heat treatment can denature protein and optimize the texture of the end products.

The plate or tubular heat exchanger is usually used to do the heat treatment according to the product’s base viscosity, and after sterilizing, the plant-based products will be cooled to 43-45℃ and then pumped into fermentation tanks.

We recommend a tubular heat exchanger for plant-based products. This is partly due to the fact that plant-based products might contain particles or fibres, which risk getting stuck in the channels of a plate heat exchanger, but mainly because certain plant-based products quickly build up layers of deposits, or fouling, on the plate surface when heated.

A bacterial culture, also called a starter culture, is added to heat-treated plant-based products for fermentation. These cultures can be a mixture of Streptococcus thermophilus and Lactobacillus bulgaricus, but other cultures are also commonly used in plant-based products. During fermentation, bacteria consume the sugars in the base and convert sugar into lactic acid, which lowers pH and alters flavor and aroma. But there’s an important difference: for plant-based products, this pH drop doesn’t have as much of an effect on product viscosity as dairy yogurt, which is why we need to add the thickeners.

The fermentation time and temperature depend on the product protein content, original and final pH value, oxygen level, etc. So the fermentation tanks need to be equipped with a pH meter, dissolved oxygen meter, and protein detector to real-time monitor these parameters. But the fermentation time and temperature for the plant-based yogurt products are still similar to dairy-based yogurt, which is 4-8 hours at 40-45℃.

After the fermentation process, the plant-based yogurt will be cooled to 20℃ by a plate heat exchanger, and then the plant-based yogurt will be pumped to the buffer tanks for filling.