The quantitative determination of volatile compounds of Chardonnay wines using HS-SPME-GC × GC/TOFMS along with the determination of odor activity value (OAV) and relative odor contribution (ROC) of volatiles are reported for the first time. The use of GC × GC/TOFMS for the analysis of Chardonnay wine of Serra Gaucha resulted in the tentative identification of 243 compounds, showing the superior performance of this analytical technique for this specific varietal wine, considering that the number of compounds usually separated by 1D-GC for this type of wine is lower. Furthermore, 42 compounds co-eluted in the first dimension and 34 of them were separated in the second dimension, while the others were resolved by spectral deconvolution (8), which indicates that the conventional 1D-GC/MS may result in misleading results. The calculation of OAV and ROC allowed the determination of the volatile compounds that presented the greater contribution to wine aroma. Ethyl octanoate, ethyl hexanoate, ethyl butanoate, and beta-damascenone showed the highest OAV and ROC values, although other 43 compounds showed also potential to contribute to wine aroma. Figures of merit of the developed method were: accuracies from 92.4 to 102.6%, repeatability from 1.2% to 13.4%, LOD from 0.001 μg L −1 (ethyl isovalerate and hexanoic acid) to 2.554 μg L −1 (ethyl 3-hydroxybutanoate), LOQ from 0.003 μg L −1 (ethyl isovalerate and hexanoic acid) to 7.582 μg L −1 (ethyl 3-hydroxybutanoate).

Headspace solid-phase microextraction (HS-SPME) combined with comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry detection (GC×GC/TOFMS) was used to analyse the volatiles in five types of wines elaborated with grapes of Cabernet Sauvignon, Merlot, Chardonnay, Sauvignon Blanc and Pinot Noir varieties. Fisher ratio, principal component analysis (PCA) and stepwise linear discriminant analysis (SLDA) were used to develop a discriminant model and, as a result, 12 volatile compounds enabled differentiation and classification of wines according to grape cultivars. A detailed examination of GC×GC/TOFMS data showed that the use of one-dimensional gas chromatography with a mass spectrometric detector (1D-GC/MS) would probably result in misidentification of some of these 12 compounds, as they showed partial coelution with other components in the first chromatographic dimension.

No abstract

No abstract

Mixtures of starch comprising starches from different botanical origins and species can improve the mechanical properties of films and coatings. Here, the aim is to develop a sustainable process of starch modification to obtain enhanced starch films through mixing three Dioscoreaceae starches and to study the films resultant mechanical (tensile strength and elongation at break), thermal (glass transition and melting temperature), and physicochemical (moisture, solubility, thickness, color, transparency, light transmission, water vapor permeability, crystallinity, and surface uniformity) properties. The films obtained after the mixing process show low moisture content and high transparency, high solubility desirable for biodegradability, and significantly different thickness. An improved light barrier is achieved and water vapor permeability barrier properties are obtained. Using differential scanning calorimetry, it is observed that the glass transition temperature of the films decreased. The starch mixture improves the mechanical characteristics of the films by 200% for tensile strength and 232% for elongation at break. After mixing, the films show increased crystallinity and no crack or pinholes in their surface. These findings demonstrate that the yam‐starch mixtures form strong and flexible films suitable for various industrial products through a simple green process.

In this study, the combined and simultaneous actions of H 2 O 2 and UV radiation on cassava starch granules were applied and the thermal, rheological, structural and colour properties were investigated. Samples of native cassava starch were oxidised with standard H 2 O 2 solutions (0.1, 0.2 and 0.5 mol L -1 ) and exposed for 1 h under UV light (UVC radiation with k = 256 nm), with constant stirring. The solutions were subsequently filtered, washed, dried and analysed. The thermogravimetric curves showed similar behaviour, with three main mass losses and an increase in the thermal stability of each sample. The oxidative modification performed caused a strong decrease in the setback and final viscosity parameters (RVA), a gradual decrease in the gelatinisation enthalpy (DSC) and relative crystallinity (XRD) and significant differences in the average roughness of the granules (NC-AFM). The X-ray diffraction powder patterns displayed the ''A'' type for all the starch granules. The colour parameters showed a decrease in the -a* value (trend to green) for all the treated samples.

No abstract

Stingless bees, important pollinating insects in the tropics, produce honey whose unique quality features differentiate their origin. The feasibility of multivariate data analysis for quality discrimination of stingless bee honey from different genera (Melipona bicolor, quadrifasciata, marginata and Scaptotrigona bipunctata) by mineral content, physicochemical and microbiological properties were investigated. The principal component analysis explained 72.12% of the total variance of the data, and the separation into two main groups in a scatter plot was observed. Group 2 was formed by Scaptotrigona genus, that showed the highest values of pH, ash, and soluble solids. Potassium was the most abundant mineral