Utilization of bottom-up approaches to produce plant-based milk analogs: a review of compositional, structural, physicochemical, functional, and nutritional properties

Plant-based foods and beverages, particularly milk analogs, are gaining increasing popularity for various reasons, including environmental, ethical, and health concerns. Currently, the market offers a wide range of plant-based milk analogs (PBMAs), most of which are manufactured using top-down methods that involve the mechanical disruption of plant tissues to create an aqueous dispersion of small particles, such as those found in soy, oat, coconut, or almond milks. However, PBMAs can also be constructed using bottom-up approaches, which involve homogenizing water, a plant-based oil, and a plant-based emulsifier together to produce a milk-like colloidal dispersion containing emulsifier-coated oil droplets dispersed in water. The plant-based oils used for this purpose include corn, flaxseed, olive, safflower, sunflower, and vegetable oils, while the plant-based emulsifiers include amphiphilic proteins, polysaccharides, and phospholipids. This article provides a comprehensive review of PBMAs prepared using the bottom-up method, including fabrication methods, ingredient functionality, and product design. In particular, the design of PBMAs with structural, physicochemical, functional, nutritional, and sensory properties similar to those of cow's milk is emphasized. In addition, the article highlights the feasibility of using PBMAs produced using the bottom-up method to create other kinds of plant-based dairy products, such as cheese, yogurt, cream, ice cream, and butter. This is typically done by creating plant-based analogs of milk fat globules and casein micelles. One of the key advantages of the bottom-up approach is that the physicochemical, functional, and nutritional properties of PBMAs can be carefully controlled, which can increase their performance and versatility. However, several technical challenges still remain, such as the need to better match the gelling, foaming, and nutritional properties of cow's milk, which will require further research.