No abstract

Two identical prototype solar dryers (direct and indirect) having the same dimensions were used to dry whole mint. Both prototypes were operated under natural and forced convection modes. In the case of the later one the ambient air was entered the dryer with the velocity of 4.2 m s−1. The effect of flow mode and the type of solar dryers on the drying kinetics of whole mint were investigated. Ten empirical models were used to fit the drying curves; nine of them represented well the solar drying behavior of mint. The results indicated that drying of mint under different operating conditions occurred in the falling rate period, where no constant rate period of drying was observed. Also, the obtained data revealed that the drying rate of mint under forced convection was higher than that of mint under natural convection, especially during first hours of drying (first day). The values of the effective diffusivity coefficient for the mint drying ranged between 1.2 × 10−11 and 1.33 × 10−11 m2 s−1.

Roselle extract was spray dried using a maltodextrin of 5 dextrose equivalent (DE) as a carrier material. The influence of a number of process variables, namely, inlet air temperature (130-190 o C), drying air flow rate (19.39-22.23 m 3 /h) and compressed air flow rate (600-800 L/h) on the yield and the physicochemical properties of the spray dried powder were investigated. The physicochemical properties of the product (moisture content, solubility, bulk density, monomeric anthocyanins content and percent polymeric color) were studied. The increase of the inlet air temperature increased the spray dried powder percent polymeric color and decreased its solubility, moisture content and monomeric anthocyanins content. The yield percentage of roselle powder was increased by increasing the inlet air temperature up to a 170 o C, and leveled off for higher temperatures. The increase in drying air flow rate increased the powder yield percentage, moisture content, the percent polymeric color and solubility and decreased its monomeric anthocyanins content, while the increase in compressed air flow rate increased the powder yield percentage and monomeric anthocyanins content and decreased its moisture content and solubility. There was no effect of drying air flow rate and compressed air flow rate on the bulk density.

Background. The total annual amounts of food loss and waste represent approximately 30% of all food supplied for human consumption. Reducing this loss and waste is a challenge and valorizing this reduction requires more effort. The present study aimed to investigate the feasibility of replacing wheat flour (WF) with different levels of green pea waste flour (GPWF) to produce pound cake. Materials and methods. To prepare GPWF, green pea waste was dried at 65°C; the dried samples were pulverized and sieved through 50 mesh sieves. Six cake samples were prepared, wherein wheat flour was replaced with GPWF at the following levels: 0 (control), 10, 20, 30, 40 and 50%. Sensory evaluation was performed to determine the acceptability of various cake samples. Based on the results of the sensory evaluation, the acceptable replacement levels were determined and the effects of the GPWF-WF replacement level (10-30%) on the rheological behavior of cake batters and the quality characteristics of baked cakes were evaluated.Results. Cake samples incorporating GPWF at levels higher than 30% significantly (p < 0.05) exhibited the lowest scores for all organoleptic characteristics compared to other samples. The storage modulus (G′) and loss modulus (G″) of all cake batters involving GPWF were higher than those of the control cake batter and they were found to be less dependent on frequency. Increasing the GPWF-WF replacement level significantly (p < 0.05) decreased cake volume, springiness, and cohesiveness; however, cake density and hardness significantly (p < 0.05) increased. The lightness (L*) and yellowness (b*) of the cake crust and crumb significantly decreased with an increase in the replacement ratio, while the highest impacts on the crumb color in terms of greenness (a*) were noted when GPWF were used at all the studied replacement levels. Conclusion.High quality cakes could be obtained at GPWF-WF replacement ratios up to 20%, as they had sensorial, textural and appearance characteristics close to that of the control cake samples.

Background. The total annual amounts of food loss and waste represent approximately 30% of all food supplied for human consumption. Reducing this loss and waste is a challenge and valorizing this reduction requires more effort. The present study aimed to investigate the feasibility of replacing wheat flour (WF) with different levels of green pea waste flour (GPWF) to produce pound cake. Materials and methods. To prepare GPWF, green pea waste was dried at 65°C; the dried samples were pulverized and sieved through 50 mesh sieves. Six cake samples were prepared, wherein wheat flour was replaced with GPWF at the following levels: 0 (control), 10, 20, 30, 40 and 50%. Sensory evaluation was performed to determine the acceptability of various cake samples. Based on the results of the sensory evaluation, the acceptable replacement levels were determined and the effects of the GPWF-WF replacement level (10-30%) on the rheological behavior of cake batters and the quality characteristics of baked cakes were evaluated. Results. Cake samples incorporating GPWF at levels higher than 30% significantly (p < 0.05) exhibited the lowest scores for all organoleptic characteristics compared to other samples. The storage modulus (G′) and loss modulus (G″) of all cake batters involving GPWF were higher than those of the control cake batter and they were found to be less dependent on frequency. Increasing the GPWF-WF replacement level significantly (p < 0.05) decreased cake volume, springiness, and cohesiveness; however, cake density and hardness significantly (p < 0.05) increased. The lightness (L*) and yellowness (b*) of the cake crust and crumb significantly decreased with an increase in the replacement ratio, while the highest impacts on the crumb color in terms of greenness (a*) were noted when GPWF were used at all the studied replacement levels. Conclusion.High quality cakes could be obtained at GPWF-WF replacement ratios up to 20%, as they had sensorial, textural and appearance characteristics close to that of the control cake samples.