The response surface method was used to investigate the results of experiment designed with the Box‐Behken approach to make known the effects of air temperature, air velocity and sample thickness, on drying time, lycopene content, ascorbic acid content, non‐enzymatic browning and color of dried tomato slices. Three levels of temperature (40 to 60C), air velocity (1.0 to 2.0 m/s) and sample thickness (7 to 11 mm) were used for the experiment. The desirability index technique was used to predict the ideal drying condition. At the best conditions of 44C air temperature, 2.0 m/s air velocity and 7.72 mm sample thickness, drying time was 527 ± 76 min, lycopene content was 62.7 ± 4.3 mg/100 g dry matter, ascorbic acid content was 3.07 ± 0.14 mg/g dry matter, brightness value was 62.92 ± 2.18, ratio of redness to yellowness was, 0.78 ± 0.05 and the non‐enzymatic browning index was 0.55 ± 0.06 absorbance unit. Practical Applications The research took practical desires of minimum drying time and non‐enzymatic browning and maximum values of lycopene content, ascorbic acid, color brightness and redness to yellowness ratio into consideration. These quality indicators are of topmost importance to the food industries involved in tomato drying. The quality of dried products obtained using response surface methodology provides industries with optimized conditions for improving the quality of dried tomatoes. The dried product is a valuable ingredient in the preparation ready to enjoy soups, sauces and pizzas.

The study investigated the influence of four microwave powers on the drying kinetics and quality of tomato slices in a microwave-vacuum dryer at vacuum pressures of 0.04, 0.05 and 0.06 MPa. The results showed that increase in microwave-vacuum drying conditions increased drying rates and resulted in decreased drying time from 84 to 14 min. The nonenzymatic browning index increased with microwave power whereas the overall flavor degradation was between 18.99 and 20.80%. The brightness and the yellowness of the dried tomatoes generally increased but there was a slight reduction in redness when compared with the fresh. The effective moisture diffusivity increased with microwave power and was 7.22 ¥ 10 -9 , 9.10 ¥ 10 -9 , 14.99 ¥ 10 -9 and 25.19 ¥ 10 -9 m 2 /s at respective microwave powers of 200, 300, 500 and 700 W. PRACTICAL APPLICATIONSMicrowave-vacuum drying is one of the advanced methods with numerous advantages including high thermal efficiency, shorter drying time and improved product quality. Tomato is the second most important vegetable with enormous health benefits, which include reduction of cholesterol, improvement of vision, maintenance of gut, lowering of hypertension, alleviation of diabetes, and prevention of urinary tract infections and gallstones. The quality of dried products obtained using the microwave-vacuum dryer provides industries with method that can be used to enhance the quality of dried tomatoes.Thedriedproductisavaluableingredientinthepreparationof soupsandsauces,as well as in cosmetics and pharmaceutical formulations. bs_bs_banner Journal of Food Quality

This research explores the mechanism of ultrasonic pretreatment on enzymolysis of defatted wheat germ protein (DWGP). The enzymolysis reaction kinetics and thermodynamics were studied after ultrasonic pretreatments using a probe-type sonicator and an ultrasonic cleaning bath, and the results were compared with traditional enzymolysis. The results showed that both the traditional and ultrasonic pretreated enzymolysis fit well to first-order kinetics. Both the temperature and ultrasound had a positive effect on the enzymolysis of DWGP, with temperature playing a dominant role. Under the optimized conditions of DWGP concentration of 1% (w/v), Alcalase concentration of 2000 U/g, time of 10 min and temperature of 50 °C, both the probe and cleaning bath ultrasonic pretreated enzymolysis showed high polypeptide concentrations (231.019 and 231.320 μg/mL) and low energy requirements. In comparison with traditional enzymolysis, these methods significantly increased the reaction rate constant (k) by 166.7% and 144.4%, 92.9% and 85.7%, 28.0% and 28.0%, 16.1% and 12.9% at 20, 30, 40 and 50 °C, and decreased the activation energy (Ea), enthalpy of activation (ΔH), Gibbs free energy of activation (ΔG) and entropy of activation (ΔS) by 68.6% and 62.4%, 74.1% and 67.5%, 34.3% and 31.2%, 1.4% and 1.3%. It can be concluded that ultrasonic pretreatment of DWGP can remarkably improve the enzymolysis efficiency and consequently leads to the production of higher polypeptide yield.

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The effect of microwave and blanch pretreatments on the drying kinetics and quality of white yam (Dioscorea rotundata) was investigated. Yam cubes destined for hot air drying at temperatures 70–90°C were predried in a domestic microwave or blanched in hot water for 1–5 min. Microwave pretreatment time had a positive significant effect on drying rate but both pretreatments had a negative influence on the ascorbic acid content and the nonenzymatic browning. The optimum drying conditions were a microwave pretreatment time of 5 min and a temperature of 70°C and a blanching time of 1 min at a temperature of 80°C. Among the models fitted, the Midilli et al. and the Page models gave the best fits for yam cubes predried with microwave and blanch, respectively. The effective moisture diffusivity for microwave‐assisted drying increased from 1.05 × 10−8 m2 s−1 to 2.00 × 10−8 m2 s−1 while the hot water blanched samples decreased from 1.53 × 10−8 to 8.81 × 10−9 m2 s−1 with time. The study demonstrates that microwave‐assisted drying could be used to enhance heat and mass transfer processes to produce better quality dried yam products.

A far-infrared radiation (FIR) catalytic laboratory dryer was designed by us and used to dry tomato. The kinetics of drying of tomato slices with FIR energy was dependent on both the distance from the heat source and the sample thickness. Numerical evaluation of the simplified Fick’s law for Fourier number showed that the effective moisture diffusivity increased from 0.193×10^–9 to 1.893×10^–9 m²/s, from 0.059×10^–9 to 2.885×10^–9 m²/s, and, from 0.170×10^–9 to 4.531×10^–9 m²/s for the 7, 9, and 11 mm thick slices as moisture content decreased. Application of FIR enhanced the flavour of the dried tomatoes by 36.6% when compared with the raw ones. The results demonstrate that in addition to shorter drying times, the flavour of the products can be enhanced with FIR. Therefore, FIR drying should be considered as an efficient drying method for tomato with respect to minimization of processing time, enhancement in flavour, and improvements in the quality and functional property of dried tomatoes.

BackgroundFood insecurity and poverty rates in Ghana are highest in the districts from latitude 8° N upwards. These have motivated several interventions aimed at addressing the food insecurity via promoting agricultural growth. An assessment of the overall impact of these interventions on food security is necessary to guide policy design and future interventions.Methods and findingsA systematic review was used to assess the cumulative evidence of the effect of development interventions, implemented from 2006 to 2016 on food security, especially in Northern Ghana. Information were retrieved from over 20 Government and non-Governmental organisations through online search and actual visits. The number of studies included in systematic review was 22. The study showed that a large number of interventions have been implemented in Northern Ghana over the study period. Access to quality extension services, training and capacity building was a major intervention strategy. About 82% of studies considered increasing production but only 14% of the studies reported on changes in yield. About 42% of the included studies used market access as a strategy but about 44% reported increase in incomes of beneficiaries (with only seven studies providing numerical evidence for this claim). The ranking of frequency of intervention strategies was in the order extension and capacity building > production > postharvest value addition > water and irrigation facilities > storage facilities > input supply. A substantial number of the studies had no counterfactuals, weakening confidence in attributing impacts on food security for even the beneficiaries.ConclusionsIt is concluded that evidence for impacts of the interventions on food security was weak, or largely assumed. A logical recommendation is the need for development partners to synchronise their measurement and indicators of food security outcomes. It is also recommended that some food security indicators are explicitly incorporated into intervention design while bearing in mind the potential need for counterfactuals.