Factors affecting droplet size of sodium caseinate-stabilized O/W emulsions containing β-carotene

This work was initiated to prepare an oil-in-water (O/W) emulsion containing -carotene by microfluidization. The -carotene was dissolved in triolein and microfluidized with an aqueous phase containing sodium caseinate (SC) as the emulsifier. Microfluization at 140 MPa resulted in O/W emulsions with a mean droplet diameter of ca. 120 nm, which was further confirmed by transmission electron microscopy analysis. The influences of SC concentration and microfluidization parameters on the droplet size of the emulsions were studied. The results showed that the mean droplet diameter decreased significantly (p <0.05) from 310 to 93 nm with the increase in SC concentration from 0.1 to 2 wt-%. However, a further increase in SC concentration did not much change the droplet diameter, although the polydispersity of the emulsions was slightly improved. The droplet diameter of the emulsions was found to decrease from 200 to 120 nm with increasing microfluidization pressure, with narrower droplet size distribution. The storage study showed that the emulsions were physically stable for about 2 weeks at 4 °C in the dark. The results provide a better understanding of the performance of SC in stabilizing the O/W emulsions

Encapsulation of flavonoid in multiple emulsion using spinning disc reactor technology

Rutin (quercetin-3-rutinoside) and anthocyanin flavonoids have numerous biological activities which are beneficial to human health such as antioxidant and anti-inflammatory effects. In order to aid delivery of their health benefits, an attempt has been made to encapsulate rutin and Hibiscus anthocyanins in multiple emulsions using a spinning disc reactor (SDR) as a novel processing aid. The encapsulation of flavonoids may prolong their shelf-life and increase their bioavailability for absorption by the body (Munin & Edwards-Lévy, 2011). The advantage of using SDR technology in the second stage of emulsification is that it does not break the droplets of the primary emulsion. The time-dependent stability of the multiple emulsions was investigated using particle size, microscopy, visual assessment and stability index measurements. At 2 wt. % emulsifier, Brij 78 was found to be capable of producing uniform droplets of the final W/O/W emulsion in the size range of 13-15 µm. The results show that the SDR technology can be used as an alternative process for making stable W/O/W multiple emulsions with a fairly narrow droplet size distribution. Rutin and anthocyanins were successfully encapsulated within the internal aqueous phase of W/O/W multiple emulsions, giving an encapsulation efficiency of >80%. In the presence of flavonoids, a reduction in the average particle size has also been observed, possibly due to its surface active properties. Confocal laser microscopy confirmed the successful formation of SDR-processed multiple emulsions

Influence of pulsed electric field-assisted dehydration on the volatile compounds of basil leaves

Pulsed electric field (PEF) was applied to basil leaves prior air drying at 40 °C. The parameters of the electric treatment were designed in such a way that (i) electroporated the tissue reversibly, provoking a permanent opening of the stomatal guard cells and (ii) electroporated the tissue irreversibly, damaging the cells. Treated leaves lost some volatile compounds due to both PEF treatments, probably related with the direct effect of permeabilization on the secretory cells of glandular trichomes. Upon drying, the irreversible permeabilization treatment showed the highest influence on the profile of volatiles in the dried leaves showing better retention of some terpenoids than the control. The performed statistical analysis allowed to select six compounds that can be used as markers both for the effect of pre-treatments prior dehydration and for the effects of dehydration itself on the volatile compounds of basil leaves

The effect of nanosecond pulsed electric field on the production of metabolites from lactic acid bacteria in fermented watermelon juice

Lactic acid fermentation offers a processing alternative for preservation of watermelon juice, which is sensitive to heat, oxygen, and light. In this study, 8.8 × 107 CFU/mL of Lactobacillus plantarum DSM 9843 in MRS broth was inoculated in 9.9 mL of sterilized watermelon juice. Nanosecond-pulsed electric field was applied during the log growth phase of the bacteria. An 19% increase in L-lactic acid, 6.8% increase in D-lactic acid and 15% increase in acetic acid were observed over control. The final pH was 3.8. These increased levels of metabolites were dependent on the applied voltages (L-lactic acid: 5.0 kV 700 pulses, D-lactic acid: 4.5 kV 700 pulses and acetic acid: 4.5 kV 1000 pulses). The nsPEF treatment did not affect the viability of the cells and sufficient numbers remained in the product after fermentation (1.6 × 109 CFU/mL in average). These results suggest that the metabolism of lactic acid bacteria was stimulated by the PEF treatment

A single nucleotide mutation in the mouse renin promoter disrupts blood pressure regulation

Renin, a major regulatory component of the renin-angiotensin system, plays a pivotal role in regulating blood pressure and electrolyte homeostasis and is predominantly expressed in the kidney. Several cAMP-responsive elements have been identified within renin gene promoters. Here, we study how 2 such elements, renin proximal promoter element-2 (RP-2) and overlapping cAMP and negative regulatory elements (CNRE), affect the transcriptional regulation of renin. We generated Tg mice (TgM) bearing BACs containing either WT or mutant RP-2 or CNRE, integrated at single chromosomal loci. Analysis of the TgM revealed that RP-2 was essential to basal promoter activity in the kidney, while renin mRNA levels did not significantly change in any tissues tested in the CNRE mutant TgM. To evaluate the physiological significance of these mutations, we used the BAC Tg to rescue hypotensive Renin-null mutant mice. As predicted, no renin expression was observed in the kidneys of RP-2 mutant/Renin-null compound mice, whereas renin expression in CNRE mutant compound mice was indistinguishable from that in control mice. Consistent with this, RP-2 mutant animals were hypotensive, while CNRE mutants had normal blood pressure. Thus, transcriptional regulation of renin expression via RP-2 but not CNRE is critical for blood pressure regulation by this gene