Effects of Modification of Encapsulant Materials on the Susceptibility of Fish Oil Microcapsules to Lipolysis

Electrospraying of phytosterols and their controlled release characteristics under in vitro digestive conditions

Phytosterols reduce cholesterol and low-density lipoprotein concentrations in humans. The use of phytosterols is restricted due to their high melting temperature, low water solubility, and chalky taste. In addition, due to its structure, it is easily oxidized and its absorption and bioavailability by the human body decrease. For these reasons, the phytosterol mixture was encapsulated by electrospraying. The carrier materials and their concentrations were optimized in mixture design as responses of the phytosterol release, minimum in the model stomach and maximum in the model intestinal solutions. As a result of the optimization, the most successful carrier material composition; was 7.19 g whey protein isolate/100 mL distilled water, 9.03 g inulin/100 mL distilled water, and 3.78 g resistant starch/100 mL distilled water. The phytosterol capsules produced in the electrospraying process at the optimized conditions were released 115.19 mg/kg in the stomach and 312.49 mg/kg in the intestinal conditions.

Effects of Rice with Different Amounts of Resistant Starch on Mice Fed a High-Fat Diet: Attenuation of Adipose Weight Gain

Increasing the amount of resistant starch (RS) in the diet may confer protective effects against chronic diseases. Rice, a good dietary source of carbohydrates, also contains RS. However, it remains unclear if RS at the amount consumed in cooked rice has a health benefit. To address the question, we examined the effects of cooked rice containing different levels of RS in a diet-induced obesity rodent model. Rice containing RS as low as 1.07% attenuated adipose weight and adipocyte size gain, induced by a moderately high-fat (HF) diet, which correlated with lower leptin levels in plasma and adipose tissue. Rice with 8.61% RS increased fecal short-chain fatty acid levels, modulated HF-diet-induced adipose triacylglycerol metabolism and inflammation-related gene expression, and increased fecal triglyceride excretion. Hence, including rice with RS level at ≥1.07% may attenuate risks associated with the consumption of a moderately HF diet.

In vitro bioaccessibility of fish oil-loaded hollow solid lipid micro- and nanoparticles

Fish oil-loaded hollow solid lipid micro- and nanoparticles were prepared by atomization of the CO2-expanded lipid mixture. The obtained particles were spherical and free-flowing with an average particle size of 6.9 μm. Fish oil loading efficiency was achieved at 92.3% (w/w). The in vitro digestive stability, lipid digestibility and EPA and DHA bioaccessibility of the fish oil-loaded particles were examined using an in vitro sequential digestion model. The mean particle diameter increased markedly after oral (15.2 μm) and gastric (32.4 μm) digestion and then decreased after the small intestinal stage (24.0 μm). Fish oil-loaded particles remained spherical and intact but mainly agglomerated on the top phase throughout the oral and gastric digestion. However, a mixed digesta was formed after the small intestinal digestion, which contained digested broken particle pieces, undigested fish oil-loaded particles, free fatty acids, monoacylglycerols and micelles. The extent of lipolysis was significantly increased for the 30% fish oil-loaded particles as compared to physical mixtures of empty hollow solid lipid particles or bulk FHSO and fish oil (p < 0.05). Moreover, EPA and DHA bioaccessibility was significantly improved from 9.7 to 18.2% with the 30% fish oil-loaded particles (p < 0.05).

Phospholipid-Protein Structured Membrane for Microencapsulation of DHA Oil and Evaluation of Its In Vitro Digestibility: Inspired by Milk Fat Globule Membrane

The present study aims to design a milk fat globule membrane (MFGM)-inspired structured membrane (phospholipid- and protein-rich) for microencapsulation of docosahexaenoic acid (DHA) oil. DHA-enriched oil emulsions were prepared using different ratios of sunflower phospholipid (SPL), proteins [whey protein concentrate (WPC), soy protein isolate (SPI), and sodium caseinate (SC)], and maltodextrin and spray-dried to obtain DHA microcapsules. The prepared DHA oil emulsions have nanosized particles. SPLs were found to affect the secondary structure of WPC, which resulted in increased exposure of the protein hydrophobic site and emulsion stability. SPL also reduced the surface tension and viscosity of the DHA oil emulsions. In vitro digestion of the spray-dried DHA microcapsules showed that they were able to effectively resist gastric proteolysis and protect their bioactivity en route to the intestine. The DHA microcapsules have a high lipid digestibility in the small intestine with a high DHA hydrolysis efficiency (74.3%), which is higher than that of commercial DHA microcapsules.

The effect of soy protein structural modification on emulsion properties and oxidative stability of fish oil microcapsules

Hydrolysates of soy protein isolate-maltodextrin (SPI-Md) conjugate were used as wall material to prepare fish oil microcapsules by freeze-drying method. Effects of the protein structural modifications on the physicochemical properties of the emulsion and the oxidative stability of the microcapsules were characterized. Compared with emulsions of SPI-Md conjugates or soy protein isolate/maltodextrin (SPI/Md) mixture, lower droplet size (212.5-329.3nm) and polydispersity index (PDI) (0.091-0.193) were obtained in the fish oil emulsions prepared by SPI-Md conjugate hydrolysates. The improved amphiphilic property of SPI-Md conjugate hydrolysates was supported by the results of surface and interfacial tension, and further confirmed by the improved emulsion stability during the storage period. Although the microencapsulation efficiency (MEE) of SPI-Md conjugate hydrolysates slightly decreased from 97.84% to 91.47% with the increasing degree of hydrolysis (DH), their oxidative stabilities (peroxide value and headspace propanal) were apparently improved compared with native SPI/Md mixture or SPI-Md conjugates system. Moreover, favorable thermal stability as well as a porous and uniform surface structure of the microcapsules coated by SPI-Md conjugate hydrolysates (DH 2.9%) was observed via the thermal analysis and scanning electron microscope (SEM) micrographs, respectively.

Review of in vitro digestion models for rapid screening of emulsion-based systems

There is increasing interest in understanding and controlling the digestion of emulsified lipids within the food and pharmaceutical industries. Emulsion-based delivery systems are being developed to encapsulate, protect, and release non-polar lipids, vitamins, nutraceuticals, and drugs. These delivery systems are also being used to control the stability and digestion of lipids within the human gastrointestinal tract so as to create foods that enhance satiety and reduce hunger. In vitro digestion models are therefore needed to test the efficacy of different approaches of controlling lipid digestion under conditions that simulate the human gastrointestinal tract. This article reviews the current status of in vitro digestion models for simulating lipid digestion, with special emphasis on the pH stat method. The pH stat method is particularly useful for the rapid screening of food emulsions and emulsion-based delivery systems with different compositions and structures. Successful candidates can then be tested with more rigorous in vitro digestion models, or using animal or human feeding studies.

Nanostructured materials in the food industry

Nanotechnology involves the application, production, and processing of materials at the nanometer scale. Biological- and physical-inspired approaches, using both conventional and innovative food processing technologies to manipulate matter at this scale, provide the food industry with materials with new functionalities. Understanding the assembly behavior of native and modified food components is essential in developing nanostructured materials. Functionalized nanostructured materials are finding applications in many sectors of the food industry, including novel nanosensors, new packaging materials with improved mechanical and barrier properties, and efficient and targeted nutrient delivery systems. An improved understanding of the benefits and the risks of the technology based on sound scientific data will help gain the acceptance of nanotechnology by the food industry. New horizons for nanotechnology in food science may be achieved by further research on nanoscale structures and methods to control interactions between single molecules.