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[EN] The effect of high pressure homogenisation (HPH) and heat treatments on physicochemical properties and physical stability of almond and hazelnut milks was studied. Vegetable milks were obtained and homogenised by applying 62, 103 and 172 MPa (MF1, MF2 and MF3, respectively). Untreated and MF3 samples were also submitted to two different heat treatments (85ºC/30 min (LH) or 121ºC/15 min (HH)). Physical and structural properties of the products were greatly affected by heat treatments and HPH. In almond milk, homogenised samples showed a significant reduction in particle size, which turned from bimodal and polydisperse to monodisperse distributions. Particle surface charge, clarity and Whiteness Index were increased and physical stability of samples was improved, without affecting either viscosity or protein stability. Hazelnut beverages showed similar trends, but HPH notably increased their viscosity while change their rheological behaviour, which suggested changes in protein conformation. HH treatments caused an increment of particle size due to the formation oil droplet-protein body clusters, associated with protein denaturation. Samples submitted to the combined treatment MF3 and LH showed the greatest stability.

A new fermented almond milk that combined the properties of both almonds and probiotics was considered to cover the current versatile health-promoting foods' demand. Almond milk fermentation with probiotic Lactobacillus reuteri and Streptococcus thermophilus was studied by using a Central Composite design with response surface methodology, and different factors (glucose, fructose, inulin and starters) were optimised to assure high probiotic survivals in the final product. The optimal formulation was physicochemically characterised throughout cold storage (28 days) and both probiotic survivals to invitro digestion and proteolysis were quantified. Results showed that a high probiotic population (>10(7) cfu/mL) was obtained in the previously optimised almond milk throughout storage time, which correspond to the addition of 0.75g of glucose/100mL, 0.75g of fructose/100mL, 2g/100mL inulin and 6mL/100mL inoculum. Glucose was used as the main nutrient and the production of mannitol by L. reuteri was detected. The fermentation process increased the viscosity values, forming a weak gel structure, whose physical properties hardly changed. Probiotic bacteria notably survived (51%) to the invitro digestion, surely related to the inulin presence, which would add value to the developed product by enhancing the potential health benefits of its consumption.

Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal, [EN] New fermented almond milks were developed by using different potentially probiotic bacteria in order to cover the current demand for health-versatile non-dairy products. An in vitro digestion/Caco-2 cell model was used to evaluate the effect of both non-fermented and fermented almond milks on the mitochondrial enzymatic activities of enterocytes. Moreover, macrophages were challenged with the in-vitro digested samples and the production of pro-inflammatory biomarkers TNF- Ñ and IL-6 was quantified. Enzymatic activities of cell cultures seemed to be stimulated by the exposure to both fermented and non-fermented almond milks. Both biomarkers decreased (p< 0.05) in fermented almond milks with either B. bifidum or B. longum. Results showed that fermented almond products favored the energetic metabolism of enterocytes and had a lower inflammatory response than initial almond milk, suggesting it is beneficial for the management of allergies/intolerances. Moreover, the fermentation process enhanced the uptake of iron by Caco-2 cells, especially when using L. rhamnosus and either B. bifidum or B. longum as starters, thus improving the product bioactivity. Therefore, new non-dairy fermented products with functional properties were developed, which might be highly potential alternatives to cow-milk products for sensitized groups of population (allergic and/or intolerant to cow milk or anemic population, among others).

Following the consumer demand of healthy vegetable products due to their interesting nutritional profiles and potential functionalities, the fermentation process of hazelnut milk with Lactobacillus rhamnosus GG and S.thermophilus was studied. The effect of different factors (glucose, inulin and inoculum contents) was analysed to ensure sufficient probiotic survivals in a minimum time. The shelf life of the optimised product was characterised in terms of its main physicochemical and quality parameters (probiotic survivals and sensory analysis). Results showed that the defined formulation allowed high probiotic survivals (approximate to 10(8)cfumL(-1)) throughout cold storage and >60% survived to the in vitro digestion process (approximate to 10(5)cfumL(-1)). Lactobacillus rhamnosus GG was no able to degrade inulin, which remained to exert health benefits in the host. The product was highly appreciated by the sensory panel during its shelf life despite the formation of a weak gel, which presented syneresis at the last storage time.

El proyecto de tesis tiene como fin desarrollar y caracterizar productos fermentados a partir de licuados vegetales con una excelente calidad nutricional y sensorial. Para conseguir el propósito mencionado se eligieron licuados de almendra, avellana y avena, cuyas propiedades fisicoquímicas y nutricionales son aptas para el proceso de fermentación. Para ello, se estudió el efecto de los tratamientos térmicos y de homogenización sobre las cualidades fisicoquímicas y de estabilidad de los diferentes licuados, para elegir en base a los resultados obtenidos, las condiciones idóneas de su obtención. Por otra parte, se seleccionaron dos cepas probióticas comerciales (L. rhamnosus GG y L. reuteri ATCC 55730) con el fin de obtener productos fermentados a partir de los licuados elegidos y, de este modo, ofrecer nuevas posibilidades y beneficios al consumidor dentro del sector de productos no-lácteos. Por otra parte, con la adición de microorganismos probióticos se pretende satisfacer la demanda actual de productos funcionales; es decir, ofrecer productos que, además del aporte de nutrientes, tengan un efecto beneficioso para la salud.