Individual Sweet Taste Perception Influences Salivary Characteristics After Orosensory Stimulation With Sucrose and Noncaloric Sweeteners.

Emerging evidence points to a major role of salivary flow and viscoelastic properties in taste perception and mouthfeel. It has been proposed that sweet-tasting compounds influence salivary characteristics. However, whether perceived differences in the sensory properties of structurally diverse sweet-tasting compounds contribute to salivary flow and saliva viscoelasticity as part of mouthfeel and overall sweet taste perception remains to be clarified. In this study, we hypothesized that the sensory diversity of sweeteners would differentially change salivary characteristics in response to oral sweet taste stimulation. Therefore, we investigated salivary flow and saliva viscoelasticity from 21 healthy test subjects after orosensory stimulation with sucrose, rebaudioside M (RebM), sucralose, and neohesperidin dihydrochalcone (NHDC) in a crossover design and considered the basal level of selected influencing factors, including the basal oral microbiome. All test compounds enhanced the salivary flow rate by up to 1.51 ± 0.12 g/min for RebM compared to 1.10 ± 0.09 g/min for water within the 1st min after stimulation. The increase in flow rate was moderately correlated with the individually perceived sweet taste (r = 0.3, p < 0.01) but did not differ between the test compounds. The complex viscosity of saliva was not affected by the test compounds, but the analysis of covariance showed that it was associated (p < 0.05) with mucin 5B (Muc5B) concentration. The oral microbiome was of typical composition and diversity but was strongly individual-dependent (permutational analysis of variance (PERMANOVA): R 2 = 0.76, p < 0.001) and was not associated with changes in salivary characteristics. In conclusion, this study indicates an impact of individual sweet taste impressions on the flow rate without measurable changes in the complex viscosity of saliva, which may contribute to the overall taste perception and mouthfeel of sweet-tasting compounds.

Structure-dependent effects of sweet and sweet taste affecting compounds on their sensorial properties.

A reduction in sugar consumption is desirable from a health point of view. However, the sensory profiles of alternative sweet tasting compounds differ from sucrose regarding their temporal profile and undesired side tastes, reducing consumers' acceptance. The present study describes a sensory characterization of a variety of sweet and sweet taste affecting compounds followed by a comparison of similarity to sucrose and a multivariate regression analysis to investigate structural determinants and possible interactions for the temporal profile of the sweetness and side-tastes. The results of the present study suggest a pivotal role for the number of ketones, aromatic rings, double bonds and the M LogP in the temporal profile of sweet and sweet taste affecting compounds. Furthermore, interactions between aggregated physicochemical descriptors demonstrate the complexity of the sensory response, which should be considered in future models to predict a comprehensive sensory profile of sweet and sweet taste affecting compounds.

Complex Coacervation of Milk Proteins with Sodium Alginate.

Beta-lactoglobulin (BLG) and bovine serum albumin (BSA) coacervate formation with sodium alginate (ALG) was investigated by turbidimetric analysis, zeta potential, particle size, viscosity, transmission electron microscopy (TEM) and isothermal titration calorimetric (ITC) measurements as a function of pH (1.0-7.0) and protein/alginate mixing ratio (1:1, 1.5:1, 2:1, 1:0, and 0:1 wt.). Critical pH values of phase transitions for BSA-ALG complexes (pHC, pHφ1, and pHφφ2) representing the formation of soluble and insoluble complexes of a protein-ALG mixture (2:1) at pH 4.8, 4.2, and 1.8, respectively. In the case of BLG-ALG, critical pH values (pHC, pHφ1, and pHφ2) were found to be 4.8, 4.2, and 1.6, respectively. The pHopt values, expressed by the highest optical density, were pH 2.8 for BSA-ALG and 2.4 for BLG-ALG. TEM and zeta-potential results showed that maximum coacervate formation occurred at pH 4.2 for both protein-polysaccharide solutions. The interaction between BLG-ALG and BSA-ALG was spontaneously exothermic at pH 4.2 according to ITC measurements. The findings of this study provide insights to a thorough understanding about the nature of interactions between milk proteins and ALG and formulate new applications for food, pharmaceutical, nutraceutical, and cosmetics applications.

Anti-inflammatory and anti-oxidant properties of laccase-synthesized phenolic-O-carboxymethyl chitosan hydrogels.

A bioactive O-carboxymethyl chitosan (CMCS) hydrogel crosslinked with natural phenolics with potential application in wound dressings was synthesized using a laccase from Myceliophthora thermophila (MTL). The highest degree of cross-linking (49.7%) was achieved with catechol. All the phenolic-CMCS hydrogels synthesized showed excellent anti-oxidant properties with a free radical scavenging activity up to 4-fold higher than in the absence of the phenolics, as quantified by the di(phenyl)-(2,4,6-trinitrophenyl)iminoazanium (DPPH) assay. In addition, the hydrogels produced showed an anti-inflammatory effect as evidenced by the inhibition of enzymes [myeloperoxidase (MPO), matrix-metalloproteinase-1 (MMP-1) and human neutrophil elastase (HNE)] over-expressed in chronic wounds. Sinapyl-CMCS hydrogels showed an MMP-1 inhibition of 37%. Further, the phenolic-CMCS hydrogels did not affect the viability of the NIH 3T3 mouse fibroblast cell line and were also able to slowly release human fibroblast growth factor 2, reaching 48.3% over a period of 28days. This study thus shows the possibility of synthesizing multifunctional bioactive chitosan based hydrogels with anti-oxidant and anti-inflammatory properties using natural occurring phenolics as crosslinkers.

Carotenoid and color changes in traditionally flaked and extruded products.

The objective of this study was to evaluate the impact of process and formulation on individual carotenoid loss in traditionally prepared cornflakes and those prepared by extrusion. The first step in the traditional process (maize grits cooking) promoted a 60% lutein content reduction and 40% in zeaxanthin loss, showing lutein more susceptibility to isomerization and decomposition. After toasting, the last step, the total loss averaged 80% for both compounds. The extruded maize in a plain formulation showed a 35% lutein and zeaxanthin reduction. However, in samples containing quinoa the decrease reached 60%, and the major loss (80%) was found in chia-containing formulations. Correlations between the color coordinate b∗, total and individual carotenoid content, were obtained. It is of a major importance that the efforts to increase carotenoid content in raw materials are complemented with attempts to reduce the losses during processing.

Chitosan hydrogel formation using laccase activated phenolics as cross-linkers.

Chitosan hydrogels are gaining increasing interest for biomedical applications due to attractive properties such as biocompatibility. In order to replace toxic chemical cross-linkers for hydrogel formation, we investigated the cross-linking potential of laccase oxidized phenolics. HPLC-TOF-MS and ATR-FTIR demonstrated that phenolics were bond to glucosamine as chitosan model substrate. Phenolics concentrations required for hydrogel formation varied from 500µM for catechol to 5000µM for sinapic acid. The hydrogels showed different swelling and release properties assessed using methylene blue release as a model. Laccase oxidized caffeic acid and pyrogallol-chitosan hydrogels showed excellent behavior in up-taking water with a swelling of 208.7% for caffeic acid. Biocompatibility results did not show any significant inhibition of growth of HEK293 cell line when phenolics like catechol or eugenol were used. Therefore, this study demonstrates that laccase oxidized phenolics are potential cross-linking agents of chitosan as a novel green approach to synthesizing chitosan hydrogels.

Use of Gallic Acid to Enhance the Antioxidant and Mechanical Properties of Active Fish Gelatin Film.

This study explores the potential roles of gallic acid in fish gelatin film for improving mechanical properties, UV barrier, and providing antioxidant activities. Glycerol, a common used plasticizer, also impacts on mechanical properties of the film. A factorial design was used to investigate the effects of gallic acid and glycerol concentrations on antioxidant activities and mechanical properties of fish gelatin film. Increasing the amount of gallic acid increased the antioxidant capacities of the film measured by radical scavenging assay and the ferric reducing ability of plasma assay. The released antioxidant power of gallic acid from the film was not reduced by glycerol. The presence of gallic acid not only increased the antioxidant capacity of the film, but also increased the tensile strength, elongation at break, and reduced UV absorption due to interaction between gallic acid and protein by hydrogen bonding. Glycerol did not affect the antioxidant capacities of the film, but increased the elasticity of the films. Overall, this study revealed that gallic acid entrapped in the fish gelatin film provided antioxidant activities and improved film characteristics, namely UV barrier, strength, and elasticity of the film.

Improvement of physical properties of gluten-free steamed cake based on black waxy rice flour using different hydrocolloids.

This study aimed to compare the effects of 1 % addition of four selected hydrocolloids (xanthan, guar, hypdroxypropylmethylcellulose and carrageenan) on quality characteristics of batter and of black waxy rice steamed cake compared to a control without hydrocolloids. Dynamic frequency sweeps of the batters at 25 °C indicated that all formulations exhibited gel-like behaviour with storage moduli (G') higher than loss moduli (G″). Hydrocolloids increased the apparent viscosity and the thixotropic behaviour, depending on the type of hydrocolloids. Xanthan had the greatest effects on both moduli, whereas carrageenan had the smallest effects. During a storage period of 4 days the cakes with xanthan remained softer than control samples. The overall acceptability of cake with xanthan and guar were higher than control. This study is the first report on using black waxy rice flour as a main raw material in gluten free cake. The results of this study provided useful information for selection hydrocolloids as ingredients that can help to improve the physical properties of waxy rice steamed cake.