Fermentation of plant-based milk alternatives for improved flavour and nutritional value

Abstract

Non-dairy milk alternatives (or milk analogues) are water extracts of plants and have become increasingly popular for human nutrition. Over the years, the global market for these products has become a multi-billion dollar business and will reach a value of approximately 26 billion USD within the next 5 years. Moreover, many consumers demand plant-based milk alternatives for sustainability, health-related, lifestyle and dietary reasons, resulting in an abundance of products based on nuts, seeds or beans. Unfortunately, plant-based milk alternatives are often nutritionally unbalanced, and their flavour profiles limit their acceptance. With the goal of producing more valuable and tasty products, fermentation can help to the improve sensory profiles, nutritional properties, texture and microbial safety of plant-based milk alternatives so that the amendment with additional ingredients, often perceived as artificial, can be avoided. To date, plant-based milk fermentation mainly uses mono-cultures of microbes, such as lactic acid bacteria, bacilli and yeasts, for this purpose. More recently, new concepts have proposed mixed-culture fermentations with two or more microbial species. These approaches promise synergistic effects to enhance the fermentation process and improve the quality of the final products. Here, we review the plant-based milk market, including nutritional, sensory and manufacturing aspects. In addition, we provide an overview of the state-of-the-art fermentation of plant materials using mono- and mixed-cultures. Due to the rapid progress in this field, we can expect well-balanced and naturally fermented plant-based milk alternatives in the coming years.

Keywords: Anti-nutrients; L-lysine; Lactic acid bacteria; Milk alternative; Mixed-culture; Nutrition; Plant processing; Plant-based; Soymilk; Synergistic; Systems biology; Vitamin.

Fig. 1

U.S. market development for plant-based milk alternative products (soy, almond and other non-dairy milk products). The data are taken from Bloomberg Surveillance (2015)

Fig. 2

Quality criteria of plant-based milk alternatives

Fig. 3

Macronutrient composition, functional components and limiting factors of common plants used for plant-based milk alternative production. The data are collected from previous work (Afaneh et al. ; Bernat et al. ; Callaway ; DebMandal and Mandal ; Duranti et al. ; Erbaş et al. ; Fernandez and Berry ; Hove ; Juliano and Hicks ; Lambo et al. ; Lampart-Szczapa et al. ; Lebiedzińska and Szefer ; Makinde and Akinoso ; Moneret-Vautrin et al. ; Noimark and Cox ; Önning et al. ; Paucar-Menacho et al. ; Ranhotra et al. ; Roy et al. ; Seow and Gwee ; Sethi et al. ; Škrbić and Filipčev ; Ulyatu et al. ; Vahanvaty ; Vanga and Raghavan ; Vidal-Valverde et al. ; Vilche et al. ; Villamide and San Juan ; Wood and Grusak 2007). The micronutrient composition data are acquired from the National Nutrient Database for Standard Reference Release (NDB) (https://ndb.nal.usda.gov/ndb/). The NDB identification of the selected materials is as follows: milk (01212), soy (16111), chickpea (45041830), pea (45272128), lupine (16076), coconut milk (45117929), almond (12061), sunflower seed kernels (12036), hemp seed (12012), sesame seed (12023), quinoa (20035), rice (20090) and oat (20132). carb, carbohydrates except fibre; funct. peptides, functional peptides; unsaturated FA, unsaturated fatty acids.

Fig. 4

Flow chart for the manufacturing of plant-based milk alternatives. The unit operations given in brackets are optional and depend on the chosen raw material and the desired quality of the final product

Fig. 5

Impact of mixed-culture fermentation on the quality of plant-based milk alternatives. Comparison between mixed-culture and mono-culture fermentation: microbial growth (A), essential amino acid level (B), vitamin level (C). The white area covers desired synergistic effects (desired), while the grey area covers undesired effects that result from mixed-culture fermentation (undesired)

Fig. 6

Impact of mixed-culture fermentation on the quality of plant-based milk alternatives. Comparison of the effects of mixed-culture and mono-culture fermentation on the elimination of anti-nutrients (A) and the alteration of mineral contents (B)