Volume 18, Issue 8-9

The purpose of this research was to evaluate the effect of soaking plantain and cassava chips in sucrose or sodium chloride (NaCl) on their physical properties and acrylamide content after frying in Conjugated Linoleic Acid (CLA)-enriched soybean oil. Plantain and cassava were cut into 1 mm thick slices and soaked for 20 min in a solution of 30% sucrose or 3% NaCl at 40 °C, separately. Soaking in sucrose and NaCl had no significant effect ( p  < 0.05) on water loss, porosity, hardness, or microstructure. The acrylamide content ranged from 634 to 3177 µg/kg. The use of CLA-enriched oil had no significant effect ( p  < 0.05) on the physical characteristics evaluated in this study. Frying reduced the CLA content in the chips from an initial 31.8% in the oil to 22.25 and 21.69% in plantain and cassava chips, respectively.

This paper systematically studied the changes of wort characteristic components under various low thermal stress boiling, and separation methods of Dimethyl-Sulfide (DMS) accumulated in wort due to low thermal stress boiling. Compared with conventional boiling, the combined boiling (boiling at 3% evaporation rate and 98 °C holding temperature for 30 min) demonstrated that the change rates of solidifiable nitrogen, iso-α-acid and color were no more than 5%, the absorbance of thiobarbituric acid (TBA) reaction mixture decreased by 13.7%, and DMS can be separated by vacuum film stripping after whirlpool. For 98 °C holding temperature boiling, the differences in absorbance of TBA reaction mixture, iso-α-acid and color were 16, 11.6 and 5%, respectively. The solidifiable nitrogen content was equivalent to the 28 mg/L limit and DMS must be removed by vacuum film stripping two times. From the perspective of application, it is necessary to improve the separation efficiency of DMS subsequently.

Carpaine in papaya leaves has the potential to treat dengue fever and it also contains antioxidants which could prevent or inhibit oxidation processes in the human body. Studies were conducted on the effects of storage on carpaine retention and antioxidant properties of dried papaya leaves. Results showed that the Weibull model could predict well the degradation kinetics of carpaine in all samples (freeze drying and hot air drying at 60 °C and 70 °C) except for hot air dried samples at 80 °C and shade dried samples (first order model). Generally, freeze dried samples showed the highest half-life whereas total polyphenols content and antioxidant properties (ABTS and DPPH free radical scavenging activities) of all dried samples decreased with storage period. An increasing trend in total colour difference (Δ E * ) was observed in all samples possibly due to chlorophyll degradation. It is thus recommended to select freeze dried samples for storage purpose due to better stability as indicated by the lowest rate constant ( k  = 0.0135 1/month) and the highest half-life ( t 1/2  = 51.2 months).

Dielectric properties of pure honey adulterated by varying amount of sugar syrup have been measured over 20 Hz to 2 MHz frequency range, at room temperature. The samples were prepared by mixing different proportions of sugar syrup in pure honey. It has been observed that, dielectric constant ( ε′ ) and dielectric loss ( ε″ ) of the mixture increases as percentage of sugar-syrup in honey increases. ε′ of the mixture decreases rapidly with the increase in frequency and achieves static value at higher frequency. ε″ decreases linearly with increase in frequency. The relaxation time corresponding to tan δ peak varies nonlinearly with increase in concentration of sugar syrup in the honey. The dielectric loss at 2 MHz, and the relaxation frequency of the mixture increases linearly with increase in concentration of sugar syrup in honey, which can be used to estimate the amount of adulteration of honey by sugar syrup.

This investigation aimed to valorize grape marc (GM) in the formulation of cakes for ideal technological, nutritional and organoleptic properties. The GM (0–20%) was used for the partial substitution of wheat flour (40–50%) and sugar (40–50%). Total polyphenols in the cake samples, their post digestion, and bioaccessibility varied from 65.49–462.07; 13.34–608.62 mg GAE/g, and 23.42–315.47%, respectively. The values of the elastic modulus of the batter were higher than those of the viscous modulus, indicating the elastic behavior of the cakes. The hardness and springiness ranged from 2.20–4.22 N, and 0.85–0.98 mm, respectively. The results predicted by mixture design revealed that the samples including 50% wheat flour, 48.73% sugar, and 1.94% GM were the best formulation for the optimization of organoleptic properties. According to the results, GM can be used to develop cakes with a good nutritional composition as well as functional, sensory, and quality attributes at the industrial scale.

When modelling a thermal process such as freezing, it is convenient to make use of thermal property models based on the food’s composition; however, there does not appear to be any suitable models specifically for thermal diffusivity. In the absence of such models, thermal diffusivity may be determined from models for effective thermal conductivity, specific heat capacity and density as functions of composition, as well as an appropriate ice fraction model. However, the accuracy of the predictions is strongly dependent on the choice of effective thermal property models. In particular, the effective specific heat capacity model must incorporate the effect of latent heat release as a function of temperature. For meat during freezing, it is recommended that the Dul’Nev Novikov effective thermal conductivity model, Pham’s ice fraction model and Chen’s effective heat capacity model are used.