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In our research marzipan samples of different sugar to almond paste ratios (1:1, 2:1, 3:1) were stored at 17 °C. Reducing sugar content was measured by analytical method, texture analysis was done by penetrometry, electric characteristics were measured by conductometry and hyperspectral images were taken 6–8 times during the 16 days of storage. For statistical analyses (discriminant analysis, principal component analysis) SPSS program was used.

According to our findings with the hyperspectral analysis technique, it is possible to identify how long the samples were stored (after production), and to which class (ratio of sugar to almond) the sample belonged. The main wavelengths which gave the best discrimination results among the days of storage were between 960 and 1100 nm. The type of the marzipan was easy to distinguish with the hyperspectral data; the biggest differences were observed at 1200 and 1400 nm, which are connected to the first overtone of C-H bound, therefore correlate with the oil content. The spatial distribution of penetrometric, electric and spectral properties were also characteristic to fructose content.

The fructose content of marzipan is difficult to measure by usual optical ways (polarimetry, spectroscopy), but since fructose is hygroscopic, the spatial distribution of spectral properties can be characteristic.

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Abstract

The objective of our work was to analyze the differences between four nut pastes, which were the following: walnut, peanut, pistachio, and tahini (sesame). The process technology of them is unknown, however, all the products contain 100% nut without any additives or flavoring.

The paste samples were measured at 25 ± 0.2 °C. The apparent viscosity at a 10 1/s shear rate during flow curve recording, and the dynamic viscosity at a constant 20 1/s shear rate was determined by viscosity measurement with the use of the MCR302 modular compact rheometer. The L*a*b* color components were determined by ColorLite sph850 spectrometer, finally, the particle sizes and shapes of the samples were analyzed by the high-speed image analysis instrument QICPIC.

The apparent viscosity and the average dynamic viscosity values of the four nut pastes were significantly different from each other. Differences were found between each paste according to the L*a*b* parameters. The complex structures of the particles are detailed and measurable, whereby the lengths and diameters of the particles can reliably be determined and fine deviations between the samples are detected. The sphericity decreases slightly with increasing particle size which means that bigger particles are more irregularly shaped.

Open access

Abstract

The objective of our experiment was to investigate the rheological properties of a compound coating depending on the pre-treatment temperature regimes.

Compound coating samples were measured at six different temperatures with 2 °C resolution between 40 and 50 °C. One part of melted samples was measured by RV1 rotational rheometer at the actual melting temperatures and the other part of melted samples was filled into 9 × 9 × 9 mm cubes molds. These cubes were cooled 24 h in freezer (−18 °C) and next day the samples were warmed to room temperature for 3 hours with different temperature combinations. The solid cubes were measured with Texture Profile Analysis (TPA) test by SMS TA-XTplus Texture Analyzer at room temperature.

Results show the effect of pre-treatment on the viscosity of the coating. Furthermore, significant differences were found among the samples cooled with different cooling methods. Our results stress the importance of the correct handling of the materials for confectioners.

Open access
Progress in Agricultural Engineering Sciences
Authors:
Katalin Badak-Kerti
,
Viktória Zsom-Muha
,
Tamás Zsom
,
Dávid Nagy
, and
József Felföldi

Abstract

In the experiments, the sound generated during the breaking of chocolate samples was examined. The fracture was performed by a precision penetrometer, the breaking sound was recorded. Texture index (TI) was calculated from the resulting signal. First the change of the resulting TI was monitored as a function of the samples' temperature. The sample groups of the same dark chocolate with different temperatures were completely separated from each other with statistical tool (LDA, linear discriminant analyses), but no trend was found to describe the change. Secondly, based on the TI, we could identify and classify the chocolate samples in the appropriate groups (based on cocoa content from 40 to 85%). According to linear discriminant analyses chocolates with different cocoa content were completely separated and showed a certain pattern. Based on the obtained results, it can be stated that the cocoa content of chocolate can be determined on the basis of TI obtained by acoustic method.

Open access