Probiotics in almond-based matrices were considered as a means of obtaining fermented products which would cover both the current demand for health-promoting foods and for alternatives to standard yoghurts. Firstly, the combined effect of high pressure homogenisation (HPH) and heat treatment on the physical stability of almond “milk” was studied. The beverage was homogenised by applying 62, 103 and 172 MPa (MF1, MF2 and MF3 respectively); MF3 was also combined with two different heat treatments (85 °C-30 min (LH) and 121 °C-15 min (HH)). Both microstructure and colloidal stability were analysed in all the processed samples to select the most suitable treatment with which to obtain a stable product. The selected almond milk was then fermented with probiotic Lactobacillus reuteri and Streptococcus thermophilus and the final product was characterised throughout cold storage time (28 days) as to pH, acidity, serum retention and starter viability. A sensory evaluation and probiotic survival to in vitro digestion was also conducted. The results showed that the physical and structural almond-milk properties were affected by both HPH and heat treatments, obtaining the greatest stability in MF3-LH samples. The fermented milk permitted probiotic survivals above the level suggested as minimum for ensuring health benefits during the entire controlled time and, hence, can be considered as a functional food. No differences in the sensory acceptability of the product were found between 1 and 28 storage days. Therefore, a new, functional, fermented product was developed, which was suitable for targeted groups, such as the lactose-intolerant and cow-milk-protein allergic populations.

The so-called vegetable milks are in the spotlight thanks to their lactose-free, animal protein-free and cholesterol-free features which fit well with the current demand for healthy food products. Nevertheless, and with the exception of soya, little information is available about these types of milks and their derivatives. The aims of this review, therefore, are to: highlight the main nutritional benefits of the nut and cereal vegetable milks available on the market, fermented or not; describe the basic processing steps involved in their manufacturing process; and analyze the major problems affecting their overall quality, together with the current feasible solutions. On the basis of the information gathered, vegetable milks and their derivatives have excellent nutritional properties which provide them a high potential and positive market expectation. Nevertheless, optimal processing conditions for each raw material or the application of new technologies have to be researched in order to improve the quality of the products. Hence, further studies need to be developed to ensure the physical stability of the products throughout their whole shelf-life. These studies would also allow for a reduction in the amount of additives (hydrocolloids and/or emulsifiers) and thus reduce the cost of the products. In the particular case of fermented products, the use of starters which are able to both improve the quality (by synthesizing enhanced flavors and providing optimal textures) and exert health benefits for consumers (i.e. probiotics) is the main challenge to be faced in future studies.