Tobacco alkaloids reduction by casings added/enzymatic hydrolysis treatments assessed through PLSR analysis.

Based on encouraged development of potential reduced-exposure products (PREPs) by the US Institute of Medicine, casings (glucose and peptides) added treatments (CAT) and enzymatic (protease and xylanase) hydrolysis treatments (EHT) were developed to study their effect on alkaloids reduction in tobacco and cigarette mainstream smoke (MS) and further investigate the correlation between sensory attributes and alkaloids. Results showed that the developed treatments reduced nicotine by 14.5% and 24.4% in tobacco and cigarette MS, respectively, indicating that both CAT and EHT are potentially effective for developing lower-risk cigarettes. Sensory and electronic nose analysis confirmed the significant influence of treatments on sensory and cigarette MS components. PLSR analysis demonstrated that tobacco alkaloids were positively correlated to the off-taste, irritation and impact attributes, and negatively correlated to the aroma and softness attributes. Additionally, nicotine and anabasine from tobacco leaves positively contributed to the impact attribute, while they negatively contributed to the aroma attribute (P<0.05). Meanwhile, most alkaloids in cigarette MS positively contributed to the impact and irritation attributes (P<0.05). Hence, this study paved a way to better understand the correlation between tobacco alkaloids and sensory attributes.

The effect of soy protein structural modification on emulsion properties and oxidative stability of fish oil microcapsules.

Hydrolysates of soy protein isolate-maltodextrin (SPI-Md) conjugate were used as wall material to prepare fish oil microcapsules by freeze-drying method. Effects of the protein structural modifications on the physicochemical properties of the emulsion and the oxidative stability of the microcapsules were characterized. Compared with emulsions of SPI-Md conjugates or soy protein isolate/maltodextrin (SPI/Md) mixture, lower droplet size (212.5-329.3nm) and polydispersity index (PDI) (0.091-0.193) were obtained in the fish oil emulsions prepared by SPI-Md conjugate hydrolysates. The improved amphiphilic property of SPI-Md conjugate hydrolysates was supported by the results of surface and interfacial tension, and further confirmed by the improved emulsion stability during the storage period. Although the microencapsulation efficiency (MEE) of SPI-Md conjugate hydrolysates slightly decreased from 97.84% to 91.47% with the increasing degree of hydrolysis (DH), their oxidative stabilities (peroxide value and headspace propanal) were apparently improved compared with native SPI/Md mixture or SPI-Md conjugates system. Moreover, favorable thermal stability as well as a porous and uniform surface structure of the microcapsules coated by SPI-Md conjugate hydrolysates (DH 2.9%) was observed via the thermal analysis and scanning electron microscope (SEM) micrographs, respectively.

Dual effects of chitosan decoration on the liposomal membrane physicochemical properties as affected by chitosan concentration and molecular conformation.

This study was devoted to a further understanding of the dependence of liposomal membrane properties on chitosan conformation and proved the dual effects of chitosan. The concentration dependence of chitosan conformation in aqueous solution was illustrated by surface tension and fluorescence probe techniques. Fluorescence and Raman spectra were subsequently employed to investigate the dynamic and structural changes of the liposomal membrane resulting from chitosan decoration. Results showed that the unfolded and crimped chains of chitosan flatly adsorbed onto the membrane surface via electrostatic attraction and favored liposome stability. Furthermore, the adsorption of crimped chains seemed stronger due to the embedding of their hydrophobic moieties. However, the presence of chitosan coils induced the increase in membrane fluidity, the intrachain disorder in lipid molecules, and the gauche conformation change of choline group. Dynamic light scattering and lipid oxidation measurements demonstrated that this perturbation was correlated with the permeation of coils into the lipid bilayer.

Coordinating fingerprint determination of solid-phase microextraction/gas chromatography-mass spectrometry and chemometric methods for quality control of oxidized tallow.

Based on optimized solid-phase microextraction/gas chromatography-mass spectrometry (SPME/GC-MS) and chemometric methods, simple, reliable and reproducible methods were described for the first time for developing a chromatographic fingerprint of oxidized tallow. Eight optimal oxidized tallow samples were used to establish the chromatographic fingerprint. Spectral correlative chromatogram was adopted to identify 33 "common components". The validation of fingerprint analysis was performed based on the relative retention time, the relative peak area of common peaks, sample stability and similarity analysis. The correlation coefficient of similarity of eight optimal oxidized tallow samples was more than 0.962, which showed that samples from different batches were consistent to some extent in spite of slightly different chemical indexes. Through principal component analysis (PCA), 14 constituents were further screened out to be the main chemical markers, which could be applied to more accurate quantitative discrimination and quality control of oxidized tallow.

Transglutaminase cross-linking effect on sensory characteristics and antioxidant activities of Maillard reaction products from soybean protein hydrolysates.

To improve the yield of Maillard peptides, a microbial transglutaminase (MTGase) was used to increase the content of 1000-5000Da peptides in soybean protein hydrolysates by using a cross-linking reaction. The sensory characteristics and antioxidant activities of corresponding Maillard Reaction Products (MSPC) was then evaluated. After cross-linking treatment the content of 1000-5000Da peptides in protein hydrolysates and the yield of Maillard peptides increased by 21.19% and 8.71%, respectively, which contributed to the improved mouthfulness of MSPC. The bitter amino acids were significantly decreased and the umami acids were markedly increased in MSPC. Volatile compounds identified by GC-MS analysis showed that the content of the important meaty flavour compounds (such as 2-methyl-3-furanthiol, bis(2-methyl-3-furyl)disulfide) of MSPC were dramatically higher than that of MRPs from uncross-linking peptides. Combined with sensory evaluation, it was confirmed that MTGase cross-linking improved the flavour Characteristics and did not affect the antioxidant activity of MSPC.

Contribution of oxidized tallow to aroma characteristics of beeflike process flavour assessed by gas chromatography-mass spectrometry and partial least squares regression.

Flavour profiles of seven beeflike process flavours (BFs) including non-oxidized or oxidized tallow were comparatively analysed by electronic nose, gas chromatography-mass spectrometry (GC-MS) and descriptive sensory analysis to characterize the headspace of BFs. Analysis of volatiles by GC-MS indicated that the effect of oxidized tallow with moderate oxidization level on Maillard reaction was more prominent than that of others, which potentially could result in an optimal meat flavour with strong, harmony and species-specific characteristics detected by sensory analysis. In addition, electronic nose data confirmed the accuracy of the GC-MS and sensory analysis results. Correlation analysis of the electronic nose measurements, sensory evaluation and characteristic compounds through Partial Least Squares Regression (PLSR) further explained that moderate oxidized tallow with peroxide value (PV) of 87.67-160 mequiv./kg, the p-anisidine value (p-AV) of 30.57-50, and the acid value (AV) of 1.8-2.2 mg KOH/g tallow was a desirable precursor for imparting aroma characteristics of beef flavour.

Characterization of odor-active compounds of various cherry wines by gas chromatography-mass spectrometry, gas chromatography-olfactometry and their correlation with sensory attributes.

To characterize the aroma of cherry wine, five samples were analyzed by quantitative descriptive sensory analysis, gas chromatography-mass spectrometry (GC-MS) and gas chromatography-olfactometry (GC-O). The aroma of cherry wines was described by 6 sensory terms as fruity, sour, woody, fermentation, cameral and floral. Fifty-one odor-active (OA) compounds were detected by GC-O and quantified by GC-MS, and 45 of them were identified. Twenty-nine OA compounds having more than 50% detection frequency were selected as specific compounds correlated to sensory attributes by partial least squares regression (PLSR). The correlation result showed ethyl 2-methyl propionate, 2,3-butanedione, ethyl butyrate, ethyl pentanoate, 3-methyl-1-butanol, ethyl hexanoate, 3-hydroxy-2-butanone, ethyl lactate, 1-hexanol, (Z)-3-hexen-1-ol, ethyl hydroxyacetate, acetic acid, furfural, 2-ethyl-1-hexanol, benzaldehyde, propanoic acid, butanoic acid, guaiacol, beta-citronellol, hexanoic acid, 2-methoxy-4-methylphenol, 2-ethyl-3-hydroxy-4H-pyran-4-one, ethyl cinnamate, 2-methoxy-4-vinylphenol were typical OA compounds, which covaried with characteristic aroma of cherry wines.