In vitro study of microencapsulated isoflavone and beta-galactosidase

Effect of microencapsulation on concentration of isoflavones during simulated in vitro digestion of isotonic drink

Isotonic drinks, fortified with microencapsulated maltodextrin and inulin isoflavone extract, were evaluated by organoleptic assessment and color measurement on the CIE L*a*b scale, then they were subjected to in vitro digestion. Changes of concentrations of isoflavones released during digestion of drinks and their ability to neutralize free radicals (ABTS) were determined. The effect of microencapsulation and storage on isoflavone content in isotonic drinks was also evaluated. In the organoleptic evaluation, beverages without additives and beverages fortified with microencapsulated extract were evaluated as better than a beverage with pure extract. Microencapsulation largely eliminated the unpleasant taste and odor of isoflavones and masked their color. Before digestion, isotonic drinks contained 29.07-43.17 μg of isoflavones in 1 ml. Microencapsulated isoflavones were released gradually during simulated digestion. The highest recovery of these compounds was observed for glycoside and malonylate derivatives of daidzein. Daidzin and genistin with encapsulation showed bioavailability of 0.02%-0.07%. The use of inulin as a carrier increased the stability of microcapsules during the storage of isotonic beverages. Microencapsulated of isoflavones from soybeans can increase the health benefits of conventional beverages available on the market.

Prevention of Bacterial Contamination of a Silica Matrix Containing Entrapped β-Galactosidase through the Action of Covalently Bound Lysozymes

β-galactosidase was successfully encapsulated within an amino-functionalised silica matrix using a “fish-in-net” approach and molecular imprinting technique followed by covalent binding of lysozyme via a glutaraldehyde-based method. Transmission electron microscopy (TEM), X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) spectroscopy were used to characterise the silica matrix hosting the two enzymes. Both encapsulated β-galactosidase and bound lysozyme exhibited high enzymatic activities and outstanding operational stability in model reactions. Moreover, enzyme activities of the co-immobilised enzymes did not obviously change relative to enzymes immobilised separately. In antibacterial tests, bound lysozyme exhibited 95.5% and 89.6% growth inhibition of Staphylococcus aureus ATCC (American type culture collection) 653 and Escherichia coli ATCC 1122, respectively. In milk treated with co-immobilised enzymes, favourable results were obtained regarding reduction of cell viability and high lactose hydrolysis rate. In addition, when both co-immobilised enzymes were employed to treat milk, high operational and storage stabilities were observed. The results demonstrate that the use of co-immobilised enzymes holds promise as an industrial strategy for producing low lactose milk to benefit people with lactose intolerance.

Preparation of Spray-Dried Soy Isoflavone-Loaded Gelatin Microspheres for Enhancement of Dissolution: Formulation, Characterization and in Vitro Evaluation

The most bioactive soy isoflavones (SI), daidzein (DAI) and genistein (GEN) have poor water solubility, which reduces their bioavailability and health benefits and limits their use in industry. The goal of this study was to develop and characterize a new gelatin matrix to microencapsulate DAI and GEN from soy extract (SE) by spray drying, in order to obtain solid dispersions to overcome solubility problems and to allow controlled release. The influences of 1:2 (MP2) and 1:3 (MP3) SE/polymer ratios on the solid state, yield, morphology, encapsulation efficiency, particle size distribution, release kinetics and cumulative release were evaluated. Analyses showed integral microparticles and high drug content. MP3 and MP2 yield were 43.6% and 55.9%, respectively, with similar mean size (p > 0.05), respectively. X-ray diffraction revealed the amorphous solid state of SE. In vitro release tests showed that dissolution was drastically increased. The results indicated that SE microencapsulation might offer a good system to control SI release, as an alternative to improve bioavailability and industrial applications.

Structural and functional properties of amylose complexes with genistein

Complexes of amylose or high-amylose corn starch (HACS) with genistein were prepared by the acidification of an alkali solution to yield a V 6IotaIotaIota structure. The amylose-genistein complexes exhibited significantly higher genistein content (11 mg/100 mg of complex) than HACS-genistein complexes (9 mg/100 mg of complex). The effect of genistein on the amylose complexes was examined in different genistein-amylose ratios, and a model for genistein organization in the amylose complexes was suggested. The complexes were stable at different pH values, with <10% of the complexed genistein released, and were stable at 30 and 50 degrees C. Lower stability was observed at 80 degrees C as shown by the extensive release of genistein. All complexes showed high retention of genistein in simulated stomach conditions and released genistein upon digestion in pancreatin solution. It is therefore suggested that the complexes can be used as carriers for the slow release of genistein.