Experiments were carried out to optimize the process parameters for production of papaya powder using foam-mat drying. Papaya pulp was foamed by incorporating methyl cellulose (0.25, 0.5, 0.75 and 1 %, w/w), glycerol-mono-stearate (1, 2, 3 and 4 %, w/w) and egg white (5, 10, 15 and 20 %, w/w) as foaming agents. The maximum stable foam formation was 72, 90 and 125% at 0.75 % methyl cellulose, 3 % glycerol-mono-stearate and 15 % egg white respectively with 9°Brix pulp and whipping time of 20 min. The foamed pulp was dried at air temperature of 60, 65 and 70 °C with foam thickness of 2, 4, 6, 8 and 10 mm in a batch type cabinet dryer. The drying time required for foamed papaya pulp was lower than non-foamed pulp at all selected temperatures. Biochemical analysis results showed a significant reduction in ascorbic acid, β-carotene and total sugars in the foamed papaya dried product at higher foam thickness (6, 8 and 10 mm) and temperature (65 and 70 °C due to destruction at higher drying temperature and increasing time. There was no significant change in other biochemical constituents such as pH and acidity. The organoleptic and sensory evaluation of the quality attributes of papaya powder obtained from the pulp of 9°Brix added with 3 % glycerol-mono-stearate, whipped for 20 min and dried with a foam thickness of 4 mm at a temperature of 60 °C was found to be optimum to produce the foam-mat dried papaya powder.

According to Indian Institute of Pulses Research Vision document, India’s population is expected to touch 1.68 billion by 2030 and the pulse requirement for the year 2030 is projected at 32 million tonnes with anticipated required annual growth rate of 4.2%. Pigeon pea is an important legume crop cultivated across several countries throughout the tropics and subtropics. They are cultivated in India, Malaysia, Indonesia, the Philippines, Caribbean, East and West Africa. Commonly known as ‘Arhar’ in Northern India, this protein rich pulse crop has growing demand in Asia. Among the pulses pigeon pea is the second most important kharif grain legume after chickpea in India and grown predominantly under rainfed conditions. The kernels are nutritionally rich containing 20-22% protein. Its cultivation would be able to provide 40-60 kg N/ha to the subsequently grown crop. The leaves and immature stems can be used as a green manure. Fallen leaves can also be used as mulch and thus help to enhance the water holding capacity of soil. Its beneficial effect as an intercrop has also been reported. Sometimes ground dry peas are mixed with wheat flour just to improve the flour quality and its protein content. Additionally, pigeon pea shares a vital part in India’s pulse import and export. Keeping all these in view the present review depicts the various aspects of pigeon pea cultivation and its status in Indian trade on pulse.

Experiments were conducted to determine the respiration rate of tomato at 10, 20 and 30 °C using closed respiration system. Oxygen depletion and carbon dioxide accumulation in the system containing tomato was monitored. Respiration rate was found to decrease with increasing CO2 and decreasing O2 concentration. Michaelis-Menten type model based on enzyme kinetics was evaluated using experimental data generated for predicting the respiration rate. The model parameters that obtained from the respiration rate at different O2 and CO2 concentration levels were used to fit the model against the storage temperatures. The fitting was fair (R2 = 0.923 to 0.970) when the respiration rate was expressed as O2 concentation. Since inhibition constant for CO2 concentration tended towards negetive, the model was modified as a function of O2 concentration only. The modified model was fitted to the experimental data and showed good agreement (R2 = 0.998) with experimentally estimated respiration rate.

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Currently, there is a growing market demand for dehydrated green mango powder for the development of value-added products. Preservation of green mangoes through drying is a good option. In this study, the influence of pretreatments and drying temperatures on drying kinetics and physicochemical properties of dried product was investigated. The sliced (4 mm thickness) green mango samples were pretreated with hot water blanching at 98°C for 3 min, 3% (w/v) ascorbic acid, and 3% (w/v) calcium chloride solutions for 1 h at room temperature (30°C). The pretreated and untreated samples were dried at 50, 60, and 70°C with an air velocity of 2.25 m/s. The dried products were ground to powder and evaluated physicochemical quality in terms of bulk and tapped density, flowability, water solubility index, rehydration capacity, total soluble solids, pH and ascorbic acid. It was observed that the moisture removal rate increased while increasing the drying temperature, and pretreated (blanching) samples dried faster than untreated samples. The experimental data were fitted to four models and evaluated for their ability to describe the drying behavior and predict the drying kinetics, of which the Logarithmic model was found to be the best. Effective moisture diffusivity and activation energy were estimated using Fick's second law of moisture diffusion and the Arrhenius-type equation, respectively, and corresponding values were 1.209 × 10 −7 to 1.566 × 10 −7 m 2 /s and 43.873 to 44.403 kJ/mol. The samples treated with blanching and ascorbic acid showed higher physical properties and ascorbic acid content, respectively.

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