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Virendra Foke ¹, M. Madhava ¹

Affiliations
1 Department of Agricultural Processing and Food Engineering, College of Agricultural Engineering, Bapatla A.P., IN

Abstract

The hydration kinetics of BPT 5204 and NLR 92 rice varieties was studied by soaking in water at temperatures of 30, 40, 50, 60 and 700C in water bath up to 180 min. To optimize the soaking conditions and design food processing equipment, the hydration data are very useful. The amount of water absorbed was high at the early stage of hydration followed by a decreased rate. Peleg's equation adequately described the hydration characteristics of rice under the experimental condition (R2 = 0.95). The Peleg's rate constant, k1, and Peleg's capacity constant, k2 decreased with an increase in temperature from 30 to 700C for both varieties of rice demonstrating that the water absorption rate increased and water absorption capacity decreased. Both the Peleg's constants were expressed by a polynomial function (R2=0.9) for relating to the temperature. Leaching loss found to be linearly related to time and temperatures. The temperature dependence of 1/k1 followed an Arrhenius type relationship. The activation energy was 26.33 kJ/mol and 31.17 kJ/mol for BPT 5204 and NLR 92 rice, respectively.

Keywords

Rice, Hydration, Peleg’s Equation, Modelling

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Virendra Foke ¹, M. Madhava ²

Affiliations
1 Department of Agricultural Processing and Food Engineering, Marathwada Institute of Technology, Aurangabad (M.S.), IN
2 Department of Agricultural Processing and Food Engineering, College of Agricultural Engineering, Bapatla, Guntur (A.P.), IN

Abstract

The hydration kinetics of black gram and black gram dhal was studied by soaking in water at temperatures of 30, 40, 50, 60 and 70 °C in water bath up to 180 min during the year 2012-13. The amount of water absorbed was high at the early stage of hydration followed by a decreased rate. Peleg's equation adequately described the hydration characteristics of samples under the experimental condition (R² = 0.95). The Peleg's rate constant, k₁, decreased from 4.80 ×10^-2 to 1.17 × 10^-2 for black gram and 3.11 × 10^-2 to 0.77 × 10^-2 for dhal. Peleg's capacity constant, k₂ decreased from 1.32 × 10^-2 to 0.393 × 10^-2 from 30 to 50 °C and then increased to 0.476 × 10^-2 up to 70°C for black gram while k₂ for dhal was increased from 7.2 × 10^-3 to 8.0 × 10^-3 with an increase in temperature from 30 to 70 °C, demonstrating that the water absorption rate increased and water absorption capacity decreased with increase in temperature. Both the Peleg's constants were expressed by a polynomial function (R² = 0.9) for relating to the temperature. The temperature dependence of 1/k₁ followed an Arrhenius type relationship. The activation energy was 20.78 kJ/mol and 31.57 kJ/mol for black gram and dhal, respectively.

Keywords

Blackgram, Dhal, Hydration, Peleg's Equation, Modeling.

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M. Padma ¹, B. Sreenivasula Reddy ², M. Madhava ²

Affiliations
1 Agricultural College, Jagtial, Karimnagar (Telangana), IN
2 College of Agricultural Engineering, Bapatla, Guntur (A.P.), IN

Abstract

Turmeric is an important commercial spice crop grown in India and it is named as "Indian saffron". Turmeric is grown in tropical countries like India, Pakistan, Myanmar, Chile, Peru, El Salvador, Japan, China, Sri Lanka, Bangladesh, Indonesia, Taiwan, Jamaica, Thailand and West Indies. The quality of turmeric powder depends upon the initial quality of rhizomes and onfarm processing of turmeric rhizomes which effects curcumin content, organoleptic characteristics, size and general appearance of the dried turmeric rhizomes. The on farm post harvest processing operations consists of washing, curing, drying, polishing, grading and colouring. Curing is a process of cooking the raw rhizomes in hot water to obtain attractive colour, characteristic aroma, destroy the viability of the fresh rhizomes and obviate the raw odour, reduces the time of drying, ensures an even distribution of colour in the rhizomes and gives a better quality product by gelatinisation of the starch (Purseglove and Brown, 1981). The study was conducted to obtain fundamental data on the effect of different floor materials on open yard sun drying and polyhouse drying. It is observed that the moisture content of turmeric fingers increases with increase in temperature of curing and curing time. At the time of 90 minutes the moisture contents were 84.41, 84.48, 84.80 and 85.77 per cent (w.b.) at the curing temperatures of 60, 70, 80 and 90°C, respectively. The moisture contents increased from the initial moisture content of 79.56 per cent (w.b.). It is observed that the floor materials affected the drying time marginally under the conditions of experiments, varied considerably from one method to the other. It is concluded that polyethylene sheet followed by tarpaulin are better floor materials to reduce the drying time and for good quality of turmeric powder.

Keywords

Turmeric Rhyzomes, Polyhouse, Open Sun Drying, Curing, Floor Materials, Curcumin Content.

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M. Padma ¹, B. Sreenivasula Reddy ², M. Madhava ²

Affiliations
1 Agricultural College, Jagtial (Telagana), IN
2 College of Agricultural Engineering, Bapatla (A.P.), IN

Abstract

Turmeric is an important commercial spice crop grown in India and it is named as "Indian saffron". Turmeric is grown in tropical countries like India, Pakistan, Myanmar, Chile, Peru, El Salvador, Japan, China, Sri Lanka, Bangladesh, Indonesia, Taiwan, Jamaica, Thailand and West Indies. India accounts for 80 per cent of the global production of turmeric. The quality of turmeric powder depends upon the initial quality of rhizomes and on-farm processing of turmeric rhizomes which effects curcumin content, organoleptic characteristics, size and general appearance of the dried turmeric rhizomes. The on farm post harvest processing operations consists of washing, curing, drying, polishing, grading and colouring. Among all, curing, drying and polishing are the important operations of turmeric processing. Curing is a process of cooking the raw rhizomes in hot water to obtain attractive colour, characteristic aroma, destroy the viability of the fresh rhizomes and obviate the raw odour, reduces the time of drying, ensures an even distribution of colour in the rhizomes and gives a better quality product by gelatinisation of the starch (Purseglove and Brown, 1981). Method of curing turmeric varies from place to place.Drying of agricultural produce is an important factor in agricultural processing for improving the keeping qualities of the produce. Utilization of the solar energy for drying the agricultural produce is important. Since all other conventional sources of energy are in the declining trend in their availability, several researchers reported that solar energy is very useful for drying agricultural produce, particularly in India, where good sunshine is available on most of the days in a year for the following reasons, (a) it is pollution free, (b) available at no cost and (c) material drying is faster. The study was conducted to obtain fundamental data on the effect of different floor materials on open yard sun drying and Polyhouse drying. It is observed that the moisture content of turmeric fingers increases with increase in temperature of curing and curing time. At the time of 90 minutes the moisture contents were 84.41, 84.48, 84.80 and 85.77 per cent (w.b.) at the curing temperatures of 60, 70, 80 and 90°C, respectively. The moisture contents increased from the initial moisture content of 79.56 per cent (w.b.). It is observed that the floor materials affected the drying time marginally under the conditions of experiments, varied considerably from one method to the other. It is concluded that polyethylene sheet followed by tarpaulin are better floor materials to reduce the drying time and for good quality of turmeric powder.

Keywords

Turmeric Rhizomes, Polyhouse, Open Sun Drying, Curing, Floor Materials.

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