Generation of magnesium enriched water-in-oil-in-water food emulsions by stirred cell membrane emulsification

This study has for the first time shown that complex food emulsifiers such as starch and protein can be applied to produce stable w/o/w emulsions with the membrane emulsification technology. Using a microporous metal membrane with a 20 μm pore size, 2% of polyoxyethylene (20) sorbitan monolaurate (Tween 20), 4% of octenyl succinic anhydride (OSA) starch or 1.5% of pea protein isolate (PPI) in the external water phase respectively was the minimum concentration necessary to stabilise the w/o/w droplets. Uniform with a span as low as 0.45 and for at least 13-day stable w/o/w emulsions of droplets between 35 and 320  μm were obtained. The release of a magnesium tracer from the internal water phase of xanthan gum-thickened w/o/w emulsions, when OSA starch and PPI were used, was found to be limited to around 3% after 13-day storage. However, w/o/w emulsions stabilised with Tween 20 were less stable with magnesium showing a release of 27% on day 13

Impact of hydrophilic emulsifier and emulsion microstructure on aroma release over w/o/w emulsions

In this thesis, the impact of the interactions between the hydrophilic emulsifiers and aroma compounds as well as emulsion microstructure including droplet size, droplet size distribution, emulsion stability and creaming on aroma release over water-in-oil-in-water (w/o/w) emulsions was investigated. Polyglycerol polyricinoleate (PGPR) was used as the only hydrophobic emulsifier to stabilise the internal water droplets in the primary water-in-oil (w/o) emulsion of the w/o/w emulsions throughout this research. Three hydrophilic emulsifiers investigated to stabilise the w/o droplets in w/o/w emulsions included a low molecular weight non-ionic surfactant, polyoxyethylene 20 sorbitan monolaurate (Tween 20), a chemically modified starch, octenyl succinic anhydride (OSA) starch and a protein, pea protein isolate (PPI), as the large molecular weight emulsifiers. The two emulsification methods of high shear mixing and stirred cell membrane emulsification were used. Controls of water and oil-in-water (o/w) emulsions were prepared with the formulation and process conditions as for the w/o/w emulsions. Emulsion microstructure was characterised in terms of droplet appearance, droplet size, droplet size distribution as well as emulsion stability over time. Both static and dynamic headspace analyses were carried out to investigate the aroma release behaviour over w/o/w emulsions. The results showed that w/o/w emulsions were a suitable vehicle for short time aroma entrapment, which was most successful for the hydrophilic aroma acetoin compared to the hydrophobic aromas acetyl pyridine and hexanal. This entrapment of the hydrophilic aroma resulted from the barrier of the oil phase in the w/o droplets to delay its diffusion or the PGPR micelles in the oil phase to entrap it in the polar inner core. The complex food emulsifiers OSA starch and PPI were for the first time successfully used in stirred cell membrane emulsification to produce similarly sized o/w and w/o/w emulsions. These were produced to eliminate the effect of droplet size in the study of aroma release. The release of aromas (i.e. diacetyl and 3-pentanone) was affected by the combination of the type of the hydrophilic emulsifier (Tween 20, OSA starch and PPI) and the type of the emulsion system (i.e. o/w and w/o/w emulsions) as well as the emulsion microstructure including droplet size, emulsion stability, interface thickness, creaming and diffusion of the internal water phase into the external water phase of w/o/w emulsions. The thinner interface laden by Tween 20 might lead to a quicker diffusion of the hydrophobic aroma 3-pentanone from the w/o droplets into w2. OSA starch interacted with the hydrophilic aroma diacetyl and 3-pentanone, and PPI interacted with 3-pentanone. These findings help to better understand the effect of the hydrophilic emulsifier and emulsion microstructure on aroma release and present a novel study to produce similarly sized emulsion droplets with complex food emulsifiers

Association Between Visceral Adiposity Index and Insulin Resistance: A Cross-Sectional Study Based on US Adults

BackgroundVisceral obesity index (VAI) is an empirical mathematical model used to evaluate the distribution and function of fat. Some studies have shown that VAI may be associated with the development of insulin resistance. In view of the differences in insulin resistance among different ethnic groups, this study attempts to analyze the special relationship between VAI and insulin resistance in American adults.MethodsWe conducted a cross-sectional study through NHANES database. A total of 27309 patients over the age of 18 from the United States took part in the survey. It was divided into two groups: the IR-positive group and the IR-negative group. The association of VAI with IR was evaluated by logistic regression analyses mainly, including univariate analysis, multivariate regression analysis, curve fitting analysis and subgroup analysis.ResultsThe results showed that in the full-adjusted model, there is a strong positive association between VAI level and insulin resistance (OR: 1.28 (1.2~1.37), P<0.001) and there is a threshold effect.ConclusionsThis study suggests that higher VAI levels are associated with insulin resistance. VAI index may be used as a predictor of insulin resistance

Impact of hydrophilic emulsifier and emulsion microstructure on aroma release over w/o/w emulsions

In this thesis, the impact of the interactions between the hydrophilic emulsifiers and aroma compounds as well as emulsion microstructure including droplet size, droplet size distribution, emulsion stability and creaming on aroma release over water-in-oil-in-water (w/o/w) emulsions was investigated. Polyglycerol polyricinoleate (PGPR) was used as the only hydrophobic emulsifier to stabilise the internal water droplets in the primary water-in-oil (w/o) emulsion of the w/o/w emulsions throughout this research. Three hydrophilic emulsifiers investigated to stabilise the w/o droplets in w/o/w emulsions included a low molecular weight non-ionic surfactant, polyoxyethylene 20 sorbitan monolaurate (Tween 20), a chemically modified starch, octenyl succinic anhydride (OSA) starch and a protein, pea protein isolate (PPI), as the large molecular weight emulsifiers. The two emulsification methods of high shear mixing and stirred cell membrane emulsification were used. Controls of water and oil-in-water (o/w) emulsions were prepared with the formulation and process conditions as for the w/o/w emulsions. Emulsion microstructure was characterised in terms of droplet appearance, droplet size, droplet size distribution as well as emulsion stability over time. Both static and dynamic headspace analyses were carried out to investigate the aroma release behaviour over w/o/w emulsions. The results showed that w/o/w emulsions were a suitable vehicle for short time aroma entrapment, which was most successful for the hydrophilic aroma acetoin compared to the hydrophobic aromas acetyl pyridine and hexanal. This entrapment of the hydrophilic aroma resulted from the barrier of the oil phase in the w/o droplets to delay its diffusion or the PGPR micelles in the oil phase to entrap it in the polar inner core. The complex food emulsifiers OSA starch and PPI were for the first time successfully used in stirred cell membrane emulsification to produce similarly sized o/w and w/o/w emulsions. These were produced to eliminate the effect of droplet size in the study of aroma release. The release of aromas (i.e. diacetyl and 3-pentanone) was affected by the combination of the type of the hydrophilic emulsifier (Tween 20, OSA starch and PPI) and the type of the emulsion system (i.e. o/w and w/o/w emulsions) as well as the emulsion microstructure including droplet size, emulsion stability, interface thickness, creaming and diffusion of the internal water phase into the external water phase of w/o/w emulsions. The thinner interface laden by Tween 20 might lead to a quicker diffusion of the hydrophobic aroma 3-pentanone from the w/o droplets into w2. OSA starch interacted with the hydrophilic aroma diacetyl and 3-pentanone, and PPI interacted with 3-pentanone. These findings help to better understand the effect of the hydrophilic emulsifier and emulsion microstructure on aroma release and present a novel study to produce similarly sized emulsion droplets with complex food emulsifiers

Dynamic aroma release from complex food emulsions

In-vitro dynamic aroma release over oil-in-water (o/w) and water-in-oil-in-water (w/o/w) emulsions stabilised with Tween 20 or octenyl succinic anhydride (OSA) starch as a hydrophilic emulsifier and polyglycerol polyricinoleate (PGPR) as a hydrophobic emulsifier was investigated. The equal-molecular-weight hydrophilic aroma diacetyl (2,3-butanedione) or relatively-more-hydrophobic 3-pentanone was added to the emulsions prepared by high speed mixing, or membrane emulsification followed by thickened with xanthan gum removing droplet size distribution and creaming as variables affecting dynamic release. Results showed the differences of w/o/w emulsions in the dynamic release compared to o/w emulsions mainly depended on aroma hydrophobicity, emulsion type, emulsifier-aroma interactions and creaming. Xanthan led to a reduced headspace replenishment. Interfacially adsorbed OSA starch and xanthan-OSA starch interaction influenced diacetyl release over emulsions. OSA starch alone interacted with 3-pentanone. This study demonstrates the potential impact of emulsifying and thickening systems on aroma release systems and highlights that specific interactions may compromise product quality

Dynamic aroma release from complex food emulsions

In-vitro dynamic aroma release over oil-in-water (o/w) and water-in-oil-in-water (w/o/w) emulsions stabilised with Tween 20 or octenyl succinic anhydride (OSA) starch as a hydrophilic emulsifier and polyglycerol polyricinoleate (PGPR) as a hydrophobic emulsifier was investigated. The equal-molecular-weight hydrophilic aroma diacetyl (2,3-butanedione) or relatively-more-hydrophobic 3-pentanone was added to the emulsions prepared by high speed mixing, or membrane emulsification followed by thickened with xanthan gum removing droplet size distribution and creaming as variables affecting dynamic release. Results showed the differences of w/o/w emulsions in the dynamic release compared to o/w emulsions mainly depended on aroma hydrophobicity, emulsion type, emulsifier-aroma interactions and creaming. Xanthan led to a reduced headspace replenishment. Interfacially adsorbed OSA starch and xanthan-OSA starch interaction influenced diacetyl release over emulsions. OSA starch alone interacted with 3-pentanone. This study demonstrates the potential impact of emulsifying and thickening systems on aroma release systems and highlights that specific interactions may compromise product quality

100 Gy 60Co γ-Ray Induced Novel Mutations in Tetraploid Wheat

10 accessions of tetraploid wheat were radiated with 100 Gy 60Co γ-ray. The germination energy, germination rate, special characters (secondary tillering, stalk with wax powder, and dwarf), meiotic process, and high-molecular-weight glutenin subunits (HMW-GSs) were observed. Different species has different radiation sensibility. With 1 seed germinated (5%), T. dicoccum (PI434999) is the most sensitive to this dose of radiation. With a seed germination rate of 35% and 40%, this dose also affected T. polonicum (As304) and T. carthlicum (As293). Two mutant dwarf plants, T. turgidum (As2255) 253-10 and T. polonicum (As302) 224-14, were detected. Abnormal chromosome pairings were observed in pollen mother cells of both T. dicoccoides (As835) 237-9 and T. dicoccoides (As838) 239-8 with HMW-GS 1Ax silent in seeds from them. Compared with the unirradiated seed of T. polonicum (As304) CK, a novel HMW-GS was detected in seed of T. polonicum (As304) 230-7 and its electrophoretic mobility was between 1By8 and 1Dy12 which were the HMW-GSs of Chinese Spring. These mutant materials would be resources for wheat breeding