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A quantitative analysis of perceived saltiness was established by combining sensory perceived NaCl concentration with electronic tongue salty response. Saltiness index (SI) was defined as the ratio of perceived NaCl concentration to the actual NaCl concentration, and was proposed to evaluate the saltiness enchantment. Method validation of the saltiness sensor included assessments of linearity, repeatability, reproducibility, limit of detection, limit of quantitation, and recovery yield. A desirable linear relationship between the logarithm of perceived NaCl concentration and saltiness was observed at NaCl concentration ranging from 45 to 90 mM with a determination coefficient exceeding 0.99. A low relative standard deviation of less than 1% was achieved in the repeatability test. Through visual evaluation, the detection and quantitation limits of the saltiness sensor for NaCl solutions were determined to be 0.01 mM and 0.1 mM, respectively. A high recovery yield (97.6–108.3%) was obtained from the spike recovery test. Optional test solvents, including ultrapure water, distilled water, and pure water, were employed without interference. Upon adding 20–35 g/100 g potassium chloride, the salty response of the salt solution increased, while the linearity of NaCl solution remained unaffected. Saltiness enhancements of 37.20 ± 0.00% and 18.17 ± 0.18% were observed for the potassium-containing salt (30%, w/w) and oyster mushroom (Pleurotus ostreatus) peptides (0.3%, w/w), respectively. This evaluation method provided an effective and quantitative approach to advancing the development of salt reduction ingredients. [ABSTRACT FROM AUTHOR]

Pea protein was used to prepare the Maillard reaction products (MRPs) through enzymatic hydrolysis and further thermal reaction with reducing sugar. A pronounced saltiness improvement in NaCl solution was observed by the addition of hydrolysates and their MRPs. Low-molecular-weight pea peptides had the strongest effect of saltiness and umami enhancement. The saltiness-enhancing effect of MRPs derived from hexoses was higher than that from pentoses. Molecular weight distribution and amino acid content of MRPs prepared under different time revealed that the hydrolysis of peptides and the initial Maillard reaction of hydrolysis products were dominant at 1 h of thermal reaction. With the extension of heating time, further reaction of small tasty peptides led to a decrease in the saltiness enhancement. The kokumi attribute was mainly contributed by the MRPs of small peptides. When the dosage of MRPs was 0.7% coupled with 0.4% NaCl, the saltiness of the solution was higher than that of the control (0.5% NaCl), which meant that the saltiness was not weakened even when the NaCl concentration was reduced by 20%. The results of the electronic tongue analysis were consistent with that of the sensory evaluation. [ABSTRACT FROM AUTHOR]

A modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) method combined with dispersive liquid-liquid microextraction (DLLME) pretreatment was developed for the determination of 5-hydroxymethyl-2-furaldehyde (HMF) in cooked japonica rice. Optimum conditions of the proposed method include MgSO4 (1 g), NaCl (0.5 g), C18 (60 mg), PSA (50 mg), the extraction solvent (CHCl3), dispersing solvent volume/extraction solvent volume (4:1), ultrapure water volume/the total volume of dispersing solvent volume and extraction solvent volume (1:1), and pH (7). HMF was concentrated by the clean-up method with the enrichment factor of 1.98. The separation of HMF was performed on an ACQUITY UPLC BEH-RP C18 column (2.1 mm × 100 mm, 1.7 μm) by the UPLC-ESI-MS/MS (ultraperformance liquid chromatography-electrospray ionization-tandem mass spectrometry). Acceptable values of HMF were achieved for the following parameters: recoveries between 82.87 and 110.48% with the relative standard deviation lower than 8.68%, accuracy in the range of 93.95–114.22%, precision (< 8.76%), limit of detection (LOD) (0.1 μg/L), and limit of quantification (LOQ) (0.3 μg/L). The concentrations of HMF were less than 1.13 μg/kg in rice samples, conspicuously increased with warming time. The color of rice samples, especially the b* value (in the range of 6.02–11.43), was well correlated with the content of HMF and the warming time. [ABSTRACT FROM AUTHOR]

In order to give the boiled sunflower seeds the rich taste, caramel aroma, and improved oxidation resistance, Maillard peptides were added to sunflower seeds in this research. Sunflower seeds sample 5 (SFS5) and sunflower seeds sample 2 (SFS2) were prepared by adding Maillard peptides of sunflower seeds (K), gluten (G), and corn (Y), at different ratio (SFS2, K:G = 8:2; SFS5, K:G:Y = 8:1:1). Component analysis showed that SFS5 and SFS2 were significantly higher in umami amino acids than the control (SFS0) without Maillard peptides. SFS5 and SFS2 contained more hybrid compounds such as pyrazines and furans which contributed to the caramel aroma of sunflower seeds. Electronic tongue analysis revealed the higher response values of umami, salty, and continuity taste for SFS5 and SFS2 than those of SFS0. Sensory evaluation results showed that the sunflower flavor, caramel aroma, umami characteristic, and overall acceptability of SFS5 and SFS2 were higher than that of SFS0. The chemical results showed that under accelerated oxidation, the SFS5 and SFS2 had significantly lower peroxide value and acid value than SFS0. [ABSTRACT FROM AUTHOR]

Anthocyanin-rich concentrates from different red radish can be used as natural food colorants. However, the development of off-flavor during extraction has been major challenge in processing industries. This work aimed to evaluate the effect of sodium chloride (NaCl) concentration in phosphoric acidified medium pH 2.5 on removal of off-flavor from red radish anthocyanin. The effect of NaCl concentration on anthocyanin properties was also evaluated. Results showed that the total glucosinolate was highly degraded at high NaCl concentration (< 500 mM) compared with control, leading to higher off-flavor development. Additionally, the glucosinolate degradation was positively and significantly correlated to isothiocyanate, while was negatively and significantly correlated with dimethyl di-, trisulfide, cedrol, triacetin, 6-methyl-5-hepten-2-one. Moreover, total monomeric and color properties of extracted anthocyanins were degraded at high NaCl concentration (< 500 mM) compared with control. The tentative anthocyanin identification by UPLC-TQ-MS showed 12 glycosylated anthocyanins substituted at C3 and C5 in tested anthocyanin extracts. In conclusion, higher NaCl concentration (< 500 mM) could not be useful for red radish off-flavor removal and anthocyanin properties. [ABSTRACT FROM AUTHOR]

A reliable and sensitive method was developed to quantify the free 2-furfurylthiol (2-FFT) in coffee brew. Using cysteine addition combined with vacuum distillation, a coffee model with trace 2-FFT and similar physicochemical properties as coffee brew was prepared for standard curve construction. During the model preparation, 2-FFT in bound form was released to free 2-FFT and removed from coffee brew through vacuum distillation. The method sensitivity, precision, accuracy and selectivity were evaluated. The limit of quantification (LOQ) was 3.0 μg/L. The coefficient of variation (CV) was 7.1%. The average recovery rates were 86.8-106.2% at spiked concentrations of 22.6, 135.8 and 181 μg/L. Coffee brews prepared using Robusta and Arabica roasted coffee beans were analyzed, and results showed that coffee brew from Robusta coffee beans had a greater amount of free 2-FFT (20.94 μg/L) than Arabica coffee beans from Yunnan (11.34 μg/L) and Columbia (15.33 μg/L), respectively. This method would be beneficial to investigate the free amount of 2-FFT in coffee brew and the sensorial assay based on free 2-FFT concentration. [ABSTRACT FROM AUTHOR]

Aroma-active compounds of red radish pigment extracts (water extract, phosphoric acidified water extracts (PAW), 10 min water or phosphoric acidified water preheated extracts (HW or HPAW), Chongqing, and Yunan extracts) were identified and characterized via sensory evaluation, gas chromatography-mass spectrometry (GC-MS), and gas chromatography-mass spectrometry with olfactometry (GC-MS/O). Three sensory attributes, namely radish odor (desirable) and radish off-odor and sulfur-like odor (undesirable), were selected to characterize the red radish pigment extracts. The correlation between the aroma-active compounds (GC-MS) and sensory attributes was studied using partial least square regression (PLSR). The sensory evaluation results revealed that Chongqing (9.30 and 8.80), water (9.00 and 9.10), Yunan (7.80 and 8.00), and HW (6.90 and 7.20) extracts showed higher radish off-odor and sulfur-like odor scores, while PAW-2.5 (7.70) and HPAW-2.5 (7.60) extracts showed higher radish odor scores. Sulfur-containing compounds, allyl isothiocyanate, 1-butyl isothiocyanate, acetonitrile, oxygen-containing compounds, terpenes, and naphthalene were positively and significantly correlated with radish off-odor and sulfur-like odor but negatively and significantly correlated to radish odor. 3-(Methylthio)propyl isothiocyanate and pyridine were positively and significantly correlated to radish odor. Additionally, 3-buten-1-yl isothiocyanate and 4-(methylthio)-3-butenyl isothiocyanate showed positive but not significant impact on radish odor. Based on their higher volatile concentration, the aroma-active compounds of the four extracts were evaluated using GC-MS/O. Thirty-three aroma-active compounds with different odor intensities were identified to be the major odorant compounds for red radish pigment extracts by panelists. Conclusively, the red radish pigment extraction conditions play a great role in its sensory characteristics. [ABSTRACT FROM AUTHOR]

The phase constitution, microstructures and microwave dielectric properties of CaZnZrSnNbO (x = 0.00, 0.05, 0.10, 0.15) ceramics prepared via a solid-state reaction method were reported for the first time. The X-ray diffraction patterns of CaZnZrSnNbO ceramics showed the monoclinic structure of ZnZrNbO and the second phase columbite CaNbO were obtained. The microwave dielectric properties of the CaZnZrSnNbO ceramics were strongly affected by the change of crystal structure and the content of second phase. With the increasing Ca content, the dielectric constant ( ε) and the Qf value decreased and the temperature coefficient of resonant frequency ( τ) moved to the positive direction. The typical values of ε = 26.64, Qf = 61,350 GHz, τ = −21.43 × 10/°C were obtained for CaZnZrSnNbO (x = 0.15) specimens sintered at 1275 °C for 6 h. [ABSTRACT FROM AUTHOR]

High performance X8R BaTiO-based ceramics with pure perovskite phase were prepared by nanocomposite doping method. The phase structure, dielectric and electrical properties and the 'relaxorlike' characteristic of ceramic materials are systemically studied. According to XRD and TEM analysis, the nanocomposite dopants via sol-gel method are uniform and well dispersive. The role of NiNbO on dielectric properties and phase structure of BaTiO-based ceramics is investigated. The properties comparison of samples prepared by nano-doping and conventional process is accomplished. SEM micrographs reveal that the grain size of BaTiO-based samples is more uniform by nano-doping process. Meanwhile, bulk densities and dielectric properties are enhanced. The 1.5 wt% NiNbO-doped sample sintered at 1280 °C shows the optimal dielectric performance (ɛ = 4160, tanδ < 1.0 %, ΔC/C ≤ ±15 %) that satisfied EIA-X8R specification. [ABSTRACT FROM AUTHOR]

The (ZnCo)ZrNbO (x = 0.1, 0.2, 0.3, 0.4) ceramics were synthesized by the conventional solid-state reaction route and sintered in the temperature range of 1160-1320 °C. The microstructure and microwave dielectric properties were investigated systematically. The X-ray diffraction results showed that the (ZnCo)ZrNbO ceramics exhibited a single monoclinic structure. The variation trend of dielectric constant ( ε) was in accordance with variation trend of relative density. The Qf value decreased with the decrease of the packing fraction. The temperature coefficient of resonant frequency (τ) moved towards positive due to the increase of B-site bond valence. In conclusion, the excellent microwave dielectric properties were obtained for ZnCoZrNbO ceramics sintered at 1240 °C for 4 h: ε = 27.93, Q × f = 68,615 GHz (where f = 6.95 GHz), and τ = −61.94 × 10/°C. [ABSTRACT FROM AUTHOR]