Characterization of industrial dried whey emulsions at different stages of spray-drying

Revealing the mechanism underlying the effects of γ-aminobutyric acid-dioscorin interactions on dioscorin structure and emulsifying properties by molecular dynamic simulations

Many studies have shown that γ-aminobutyric acid (GABA) exhibits various beneficial biological activities, including gut-modulating, neuro-stimulating, and cardio-protecting activities. Naturally, GABA exists in small amounts in yam, which is primarily synthesized by the decarboxylation of L-glutamic acid in the presence of glutamate decarboxylase. Dioscorin, the major tuber storage protein of yam, has been shown to have good solubility and emulsifying activity. However, how GABA interacts with dioscorin and affects their properties has yet to be clarified. In this research, the physicochemical and emulsifying properties of GABA-fortified dioscorin, which was dried by spray drying and freeze drying, were studied. As results, the freeze-dried (FD) dioscorin produced more stable emulsions, while the spray-dried (SD) dioscorin adsorbed more rapidly to oil/water (O/W) interface. The fluorescence spectroscopy, ultraviolet spectroscopy and circular dichroism spectroscopy showed that GABA changed the structure of dioscorin, by exposing its hydrophobic groups. The addition of GABA significantly promoted the adsorption of dioscorin to the O/W interface and prevented droplets coalescence. The results of molecular dynamics simulation (MD) showed that GABA destroyed the H-bond network between dioscorin and water, increased surface hydrophobicity and finally improved the emulsifying properties of dioscorin.

Freeze-drying of black chokeberry pomace extract-loaded double emulsions to obtain dispersible powders

Black chokeberry pomace extract is rich in polyphenolic antioxidants, including anthocyanins. Added to foods, bioactive compounds of the extract can undergo undesirable changes both during food handling and digestion. In this study, we examined the possibility of encapsulating a considerable amount of black chokeberry pomace extract in the inner water phase of double emulsion (water-in-oil-in-water), for intended use in food applications. Furthermore, this study investigated the feasibility of double emulsions loaded with the extract for freeze-drying to obtain dispersible powders. A substantial amount (2.1%) of black chokeberry pomace extract was efficiently encapsulated in the inner water phase of double emulsion and remained entrapped during 60 days of storage (<97%) as well as during the freeze-drying of emulsions. Reconstituted emulsions obtained after the rehydration process were found to show monomodal droplet size distribution, decent creaming stability (approximately 97%), and good encapsulation efficiency (95.36%). Such characteristics of powdered double emulsions loaded by black chokeberry pomace extract make them suitable for food application as retainer and preservative of bioactive polyphenolic-rich extracts. PRACTICAL APPLICATION: Powders of double emulsions loaded by black chokeberry pomace extract could be used as a source of bioactive polyphenolic compounds.

Whey proteins as stabilizers in amorphous solid dispersions

Whey proteins are extensively used as nutritional supplements but have so far not been investigated as co-formers for amorphous solid dispersions (ASD) to enhance the solubility and dissolution rate of poorly water soluble drugs. In this study, whey protein isolate (WPI) and whey protein hydrolysate (WPH) were each mixed with three poorly water soluble drugs (indomethacin: IND, carvedilol: CAR and furosemide: FUR) and prepared as ASDs at 50% (w/w) drug loading using vibrational ball milling. Subsequently, solid state characteristics, dissolution rate and physical stability of the obtained samples were analyzed. All ASDs showed a significant increase in their glass transition temperatures, as well as faster dissolution rates and higher apparent solubilities compared to both the respective pure crystalline and amorphous drugs. The saturation solubility of the drugs was increased in the presence of the whey proteins, and the investigated ASDs showed supersaturation by attaining higher drug concentrations compared to the respective saturation solubilities. Upon storage, ASDs containing IND were found to be physically stable for at least 27 months, whereas, ASDs containing CAR or FUR were stable for about 8 months and 17 months, respectively. This was a tremendous increase in physical stability compared to the pure amorphous drugs which recrystallized within less than one week. Overall, WPI and WPH proved to be promising co-formers and amorphous stabilizers in ASD formulations.