Addition of Trans-Resveratrol-Loaded Highly Concentrated Double Emulsion to Yoghurts: Effect on Physicochemical Properties.

Trans-resveratrol (RSV) needs to be encapsulated to maintain its beneficial properties on the human body. This is due to its extreme photosensitivity, short biological half-life, and easy oxidation. In this study, the use of double emulsions for RSV encapsulation and their further application on functional yoghurts was studied. Different types of yoghurts were prepared: with and without RSV and with two types of volumetric emulsion formulations (20/80 and 30/70). In order to study the influence of the addition of double emulsions to the physical properties of the prepared yoghurts, they were characterised fresh and after a month under storage at 4 °C, in terms of droplet size, morphology, stability, rheology, texturometry, colorimetry, and antioxidant capacity. Results obtained showed that the presence of emulsion in the yoghurts produced a generalised decrease in the predominant droplet size (from 48 µm to 15-25 µm) and an increase in the stability. Additionally, a predominantly elastic character was observed. The firmness values obtained were very similar for all the yoghurts analysed and did not suffer important modifications with time. A slight colour variation was observed with storage time in the control sample, whereas a more notable variation in the case of emulsion yoghurts was observed. An appreciable increase of the antioxidant capacity of the final functional yoghurt (100 g) was observed when it contained 5-8 mg of RSV. Encapsulated RSV added to yoghurts presented a larger protection against RSV oxidation compared with free RSV, presenting a larger antioxidant inhibition after one month of storage. Moreover, the antioxidant capacity of yoghurts with encapsulated RSV was not affected under storage, since slight reductions (3%) were registered after one month of storage at 4 °C.

Simultaneous encapsulation of trans-resveratrol and vitamin D3 in highly concentrated double emulsions.

BACKGROUND: Encapsulation of biocompounds is essential to protect them from environmental factors that could enhance their oxidation or cause them to lose their beneficial properties due to extreme photosensitivity, among other factors. The main goal of this work was to study the feasibility of preparing concentrated double emulsions with a high loading capacity containing simultaneously trans-resveratrol (RSV) and vitamin D3 (VitD3 ). Such emulsions could be used for food fortification or pharmaceutical formulations or as vehicles for targeted controlled release. RESULTS: In order to achieve large concentrations of the encapsulated compounds, all the double emulsions were formulated using a W1 /O in W2 ratio of 80/20, while the ratios tested for W1 in O where 20/80 and 30/70. All the emulsions were characterized by droplet size, morphology, colloidal stability and encapsulation efficiency (EE) over a period of 6 weeks. VitD3 and RSV concentration were determined by a technique based on reverse-phase high-performance liquid chromatography. The viability of preparing concentrated W1 /O/W2 emulsions containing both biocompounds has been demonstrated with satisfactory results. Initial RSV concentrations in the concentrated double emulsions formulated varied from 5.0 to 8.3 mg L-1 , while for VitD3 values of 28-32 mg L-1 were obtained. The presence of VitD3 retarded RSV release in the formulated emulsions. It was observed that after 1 week of storage RSV EE increased around 10-50% when VitD3 was simultaneously encapsulated. CONCLUSION: Simultaneous encapsulation of RSV and VitD3 was possible in high internal phase emulsions. The emulsions presented high colloidal stability, being suitable for food fortification applications. © 2020 Society of Chemical Industry.

Enhancing trans-Resveratrol loading capacity by forcing W1/O/W2 emulsions up to its colloidal stability limit.

Trans-Resveratrol (3, 5, 4'-trihydroxystilbene) is a naturally occurring polyphenol easily oxidizable and extremely photosensitive with a short biological half-life that must be encapsulated to maintain its beneficial properties on the human body. The aim of this work is to increase the amount of resveratrol encapsulated using concentrated double water-in-oil-in-water (W1/O/W2) emulsions, making these systems more interesting as ingredient for functional food products and/or pharmaceutical formulations. The concentration of the inner emulsion (W1/O) for several external (W1O/W2) ratios was optimized in terms of encapsulation efficiency (EE), colloidal stability and rheological behaviour. W1/O emulsions formulated with ratios of 30/70 and 40/60 were used to obtain double emulsions (with ratios of 20/80 up to 80/20 of W1O/W2). Trans-Resveratrol EE increased up to 90 % when the most concentrated double emulsions were prepared for both W1/O ratios tested. The maximum resveratrol concentrations on double emulsions were 10.8 mg/L and 14.4 mg/L when 30/70 and 40/60 of W1/O ratios were used, respectively. However, longer time stability was found for double high internal phase emulsions (W1O/W2) with a ratio of 30/70 of W1/O. The double emulsion formulated with a 80/20 W1O/W2 volumetric ratio together with 30/70 of W1/O seems suitable to be used as ingredient for pharmaceutical and food devices/products due to its high colloidal stability, clearly pseudoplastic and elastic behaviour, high EE and large trans-Resveratrol carrier capacity.