Short/medium chain fatty acids have well known health effects such as gut immune regulation and ketogenesis. The ability to realise these health effects is potentially limited by their rapid gastro-intestinal lipolysis. It was proposed that synthesising novel interesterified lipids via an interesterification reaction to generate a combination of short/medium and long chain fatty acids would modulate their gastrointestinal digestion. Using in vitro gastric and gastro-intestinal digestion models, the effect of the fatty acid chain length and interesterification on the rate and extent of lipolysis was analysed. Overall, "pure" (consisting of a single fatty acid) lipids of ≤C8 underwent rapid lipolysis releasing three fatty acids after intestinal hydrolysis while lipids of ≥C10 released two fatty acids after intestinal hydrolysis. The most interesting observation is that the extent of gastric lipolysis of C4 fatty acids was much lower when they were interesterified with longer chain fatty acids compared to that with the pure C4 triglyceride. Tributyrin underwent ∼60% lipolysis by gastric lipase as indicated by a decrease in total fatty acid release during SIF lipolysis after pre-exposure to rabbit gastric lipase (RGL) in SGF. In comparison, the C4-C8 interesterified lipid exhibited only a 18.1% decrease, and the C4-C18:1 interesterified lipid a 6.1% decrease in total fatty acid release in SGF-SIF. These results suggest that interesterification modulates the digestion of butyric acid from within the stomach to later in the intestine. This study reveals that the design of interesterified lipids alters the timing, but not the extent of short chain fatty acid delivery in the gastrointestinal tract. Such understanding has likely benefits for designing novel interesterified lipids which may have unique applications in various dietary and therapeutic modalities.

The aim of this study was to investigate the microstructure and long-term mechanical as well oxidative stability of a new class of spray dried emulsion containing ultrahigh oil content. Emulsion (20 wt% oil) stabilized by whey protein (1 wt%) was thermally cross-linked at 82 degrees C for 10 min and spray dried without any additional wall materials using inlet/outlet air temperature of 105 +/- 2/65 +/- 2 degrees C, respectively at a pilot scale. Confocal micrograph showed cohesive cross-linked whey protein film present at the oil-water interface and at the powder surface stabilising the oil powder particles containing 953 wt% oil. The mean droplet size of parent emulsion (0.21, 038, 0.76, 231 gm) significantly influenced the mechanical stability of the resulting oil powder in terms of oil leakage (2.73, 0.93, 4.1, 7.54 wt%) upon compaction. Scanning electron microscopy revealed the level of surface oil and porous "sponge" like internal microstructure of the oil powder with polyhedral, closely packed droplets. Strong correlations existed between the mechanical properties of the oil powder and the oxidative stability over 5 months. The kinetics of oxidation of oil powder was higher than that of corresponding bulk oil with or without added antioxidants as evidenced by evolution of primary oxidation products (hydroperoxides) and secondary oxidation products (hexanal). This might be due to the multi-step processing (e.g. homogenization, thermal cross-linking, spray drying) as well as inability of the cohesive but permeable protein matrix to protect the ultra-high content of oil droplets from diffusion of oxygen and prooxidants. (C) 2015 Elsevier Ltd. All rights reserved.

Summary Vegetable oils high in polyunsaturated fatty acids ( PUFA ), like soybean oil ( SO ), are known for lowering the risk of consumers for contracting cardiovascular disease as well as improving cognitive health. However, they are more susceptible to lipid oxidation than recently introduced high‐oleic cultivars like high‐oleic sunflower oil ( HOSFO ). Thus, the objective of this study was to increase the stability of PUFA oils to maintain the aforementioned health benefits by supplementing them with industrially relevant antioxidant compounds that prevent or delay oxidation during food production and storage. Herein, a variety of synthetic and natural antioxidants tested alone or in mixtures was screened to bring the stability of SO closer to that of HOSFO . Oils were stored under accelerated conditions (35 °C) in the dark for 28 weeks, and the evolution of primary (hydroperoxides) and secondary (hexanal) lipid oxidation products was monitored. Oxidative stability index data showed that addition of 300 ppm of ascorbyl palmitate ( AP ) stabilised SO to the greatest magnitude. Further, a combination of AP (300 ppm) and M ‐ TOC (1000 ppm) was able to limit hydroperoxide and hexanal formation in SO at 35 °C for 12 weeks. It was demonstrated that assessing multiple quality parameters for lipid stability are a necessary undertaking.

The present study sought to understand how the microstructure of protein gels impacts lipolysis of gelled emulsions. The selected system consisted of an oil-in-water (o/w) emulsion embedded within gelatin gels. The gelatin-gelled emulsions consisted of a discontinuous network of aggregated emulsion droplets (mesoscale), dispersed within a continuous network of gelatin (microscale). The viscoelastic properties of the gelled emulsions were dominated by the rheological behavior of the gelatin, suggesting a gelatin continuous microstructure rather than a bicontinuous gel. A direct relationship between the speed of fat digestion and gel average mesh size was found, indicating that the digestion of fat within gelatin-gelled emulsions is controlled by the ability of the gel's microstructure to slow lipase diffusion to the interface of fat droplets. Digestion of fat was facilitated by gradual breakdown of the gelatin network, which mainly occurred via surface erosion catalyzed by proteases. Overall, this work has demonstrated that the lipolysis kinetics of gelled emulsions is driven by the microstructure of protein gels; this knowledge is key for the future development of microstructures to control fat digestion and/or the delivery of nutrients to different parts of the gastrointestinal tract.

We determined the bioavailability of vitamin E from self-assembly structures in patients with diagnosed chronic pancreas insufficiency. Vitamin E solubilized in dispersed inverted bicontinuous cubic phase and in micellar formulation was delivered directly to the small intestine by tube-feeding. A cross-over study with randomization of 6 subjects and 2 treatments including a combined dose of 18 mg (27 IU) of vitamin E (RRR-[5,7-methyl-((2)H6)]-α-tocopherol) and 27 mg (27 IU) vitamin E acetate (RRR-[5-methyl-(2)H3]-α-tocopheryl acetate) was applied over a time period of 1 h. Plasma samples were collected for 56 h and analyzed by liquid chromatography-mass spectrometry. Appearance of labeled tocopherols originating from the treatment started at 25 h and reached Cmax (0.6-4.6 μM depending on subject) in the 7-9 h window. From the Tmax onwards, both forms of tocopherols diminished slowly to 30-50% of their maxima within 56 h. Strong inter-individual variation was observed in the plasma appearance curves (relative standard deviation varied between 38-45%). No significant discrimination was found between the absorption of free or acetylated forms of deuterated α-tocopherol confirming that application of acetylated α-tocopherol provides the same bioavailability as free α-tocopherol. This observation is valid in both dispersed inverted bicontinuous cubic phase and micellar formulations. Furthermore, since the area-under-the-curve values from cubic phase and from micellar formulations are similar, the cubic phase formulation could represent an alternative delivery system for lipophilic micronutrients in conditions or studies where polysorbate-based micelles cannot be generated.

Monodisperse water-in-oil-in-water (WOW) double emulsions have been prepared using microfluidic glass devices designed and built primarily from off the shelf components. The systems were easy to assemble and use. They were capable of producing double emulsions with an outer droplet size from 100 to 40 μm. Depending on how the devices were operated, double emulsions containing either single or multiple water droplets could be produced. Pulsed-field gradient self-diffusion NMR experiments have been performed on the monodisperse water-in-oil-in-water double emulsions to obtain information on the inner water droplet diameter and the distribution of the water in the different phases of the double emulsion. This has been achieved by applying regularization methods to the self-diffusion data. Using these methods the stability of the double emulsions to osmotic pressure imbalance has been followed by observing the change in the size of the inner water droplets over time.

Self-diffusion NMR is used to investigate monodispersed oil in water emulsions and the subsequent gel formed by removing the water through evaporation. The radius of the oil droplets in the emulsions is measured using a number of diffusion methods based on the measurement of the mean squared displacement of the oil, water, and tracer molecules. The results are consistent with the known size of the emulsions. Bragg-like reflections due to the restricted diffusion of the water around the oil droplets are observed due to the low polydispersity of the emulsions and the dense packing. The resulting data are fitted to a pore glass model to give the diameter of both the pools of interstitial water and the oil droplets. In the gel, information on the residual three-dimensional structure is obtained using the short time behavior of the effective diffusion coefficient to give the surface to volume ratio of the residual protein network structure. The values for the surface to volume ratio are found to be consistent with the expected increase of the surface area of monodisperse droplets forming a gel network. At long diffusion observation times, the permeability of the network structure is investigated by diffusion NMR to give a complete picture of the colloidal system considered.

We developed a method that enables differentiation between liquid crystalline-phase particles corresponding to different space groups. It consists of controlled tilting of the specimen to observe different orientations of the same particle using cryogenic transmission electron microscopy. This leads to the visualization of lattice planes (or reflections) that are present for a given structure and absent for the other one(s) and that give information on liquid crystalline structures and their space groups. In particular, we show that we can unambiguously distinguish among particles having the inverted micellar cubic (space group Fd(3)m, 227), the inverted bicontinuous gyroid (space group Ia(3)d, 230), the inverted bicontinuous diamond (space group Pn(3)m, 224), and the inverted bicontinuous primitive cubic structure (space group Im(3)m, 229).