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Mathematical Modelling of Drying Characteristics of Lemon Grass Leaves (Cymbopogon citratus)
2022
Oyebola Odunayo Olabinjo
Drying characteristics of Lemon grass leaves using an oven dryer was studied at four different temperatures (40, 50, 60 and 70°C). The effect of the drying temperatures on moisture content of the leaves was investigated. Thirteen drying models were fitted to the drying data to establish the model that best describes the drying characteristics of Lemon grass leaves. The best model was determined by the model with the lowest value of SSE and root mean square error (RMSE), and the highest value of coefficient of determination (R2). Hii et al. model satisfied the conditions for selecting the most suitable and reliable model with R2, SSE and RMSE values of the model was 0.9964, 0.0250 and 0.0214 respectively. This model is most suitable at 40°C. The effective diffusivity (Deff) values ranged from 8.92452 × 10-12 m2/s to 16.00657 × 10-12 m2/s and increases as temperature increases. It was further observed that the amount of energy required to eliminate moisture within the leaves was in the range of 19.85 kJ/mol - 19.86949 kJ/mol. Dried lemongrass leaves can be used in food preservation as an alternative to synthetic substances that have recently become less acceptable to consumers. Consumers accept natural food products that are universally acknowledged as safe, such as lemon grass with essential oils, and they also fit the standards for green processing.
Afficher plus [+] Moins [-]Effects of Different Drying Methods on Modelling, Energy Consumption and Final Quality of Tomato (Lycopersicum esculentum Mill)
2019
Hakan Polatcı | Yücel Erkmen
Agricultural developments mostly depend on rapidly increasing world population. Tomato is a highly nutritious vegetable. Post-harvest technologies are often applied to prolong the consumption periods of tomato. Drying is one of the oldest methods of conservation. In this study, five different drying methods (oven drying, vacuum oven drying, sensitive drying, shaded-open atmosphere drying and sun drying) was used. Drying processes were carried out with dryers at 55°C, 60°C, 65°C and 70°C temperatures. All drying trials were performed in three replications. Drying performance (drying duration, final moisture content), drying kinetics, colour analysis, energy consumption, chemical analyses were performed for all drying methods. Fresh samples reached to desired moisture contents in 20-300 hours. To define time-dependent changes in moisture contents, Page, Logarithmic and Midilli-Küçük equations were used. Page equation yielded the worst estimations. There were not significant differences in “a” redness values of fresh samples, 65-70C of oven dryer and all temperatures of sensitive dryer. Sensitive dryer yielded the closet pH values to fresh samples. Based on current findings, it was concluded that oven drying, and sensitive drying were suitable for drying Selinus tomato variety.
Afficher plus [+] Moins [-]Design and Manufacture of a Dryer for Corn Grains, Ears and Cobs
2022
Humberto Rodríguez-Fuentes | Juan Arredondo-Valdez | Wilgince Apollon | Urbano Luna-Maldonado | Héctor Flores-Breceda | Uziel Francisco Grajeda-González | Alejandro Isabel Luna Maldonado
A corn dryer prototype was manufactured for Mexican small-scale farmers in order to avoid them paying fines for corn with a high-moisture content when selling their corn on to stores. The dryer comprised two large boxes perforated by round holes and containing stainless steel trays subjected to a hot air temperature of 45°C within the batch. The accumulated grain in both boxes was 200 mm and the airflow rate were 0.56 m3 s-1. The corn ears layer was of 80 mm of depth in each of the boxes. The airflow rate was 0.34 m3 s-1. Within eight hours, we sampled corn grain in nine points of each box and found that the mean corn grain moisture content was reduced from 30.36% to 10.47% for box 1 whereas for box 2 it was reduced until 14.72%. The fuel consumption for drying was 0.55 kg h-1 of kerosene. In Box1, the exponential regression model for corn grain moisture content had an R² of 0.9143 whereas Box 2 exponential regression model had an R² was of 0.6642. In Box 1, the exponential regression model for corn ear moisture content had an R² of 0.9616 whereas Box 2 had an R² was of 0.9400. Both models for corn cob moisture content had an R² of 0.9639. Two-layer corn dryers can be used to harness gas or fuel energy to speed up drying for storage.
Afficher plus [+] Moins [-]Effect of Storage Duration and Processing Parameters on Some Cooking Properties of Ofada Rice
2018
Oludare Olumuyiwa Adekoyeni | Adedola Sulaiman Adeboye
Effects of storage duration, soaking time and parboiling temperature on cooking properties (cooking time, water uptake ratio, solid loss, cooked kernel length, and amylose) of Ofada rice was determined and optimised using response surface methodology. Storage duration, soaking time and parboiling temperature were 1, 5, and 9 months; 1, 3, and 5 days; and 80, 100, and 120°C. Data were analysed by ANOVA and regression analysis. The cooking time ranged between 14-38 min, water uptake ratio (WUR) 2.51-4.61, solid loss 1.47-4.78%, cooked kernel length 6.32-11.90 and amylose 17.34-26.28%. There exist significant differences in the cooking properties. The coefficient R2 ranged between 0.97-0.75 which is a positive indicator of the model fitness. Storage duration and parboiling temperature influenced cooking except in solid loss and cooked kernel length respectively. Effect of soaking time was found prominent in WUR and solid loss. Optimum treatment for quality cooking properties are storage of paddy for 5 months, soaking for 18h and parboiling at 80°C to yield 20 min cooking time, 4.22 water uptake ratio, 4.11% solid loss, 10.58 mm cooked kernel length and 25.08% amylose. The validated experiment yielded 21.41 min, 3.99, 2.73%, 8.20 mm and 26.39% for cooking time, water uptake ratio, solid loss, cooked kernel length and amylose respectively.
Afficher plus [+] Moins [-]Determination of Drying Characteristics, Energy Consumption and Quality Values of Black Mulberry Fruit (Morus nigra L.) Dried Under Different Conditions
2021
Muhammed Taşova | Hakan Polatcı | Adil Koray Yıldız
There are about 68 types of mulberry fruit with a wide ecological production area. Different mulberry species are grown in large fields in Turkey. Mulberries are largely dried-consumed, but sometimes they are used as fruit juice. In this study, black mulberry fruit was collected in two different ripening levels (semi-ripe and full-ripe) and oven-dried at 50, 60 and 70°C drying temperatures. Initial moisture contents of semi-ripe and full-ripe fruits were determined as 86.74% and 82.95%, respectively. Fruits were dried to have final moisture levels of 10-15%. Drying duration, drying models, effective diffusion, activation energy, specific energy consumption, color parameters and chemical properties of dried fruits were examined and the effect of ripening levels and drying temperatures were investigated. In terms of drying duration, while full-ripe fruits dried in a shorter time, effective diffusion, activation energy and specific energy consumption values were found to be higher than semi-ripe fruits. In terms of color parameters, semi-ripe fruits are recommended to be dried at 50 or 60°C drying temperatures and full-ripe fruits should be dried at 50°C drying temperature for better preservation of color parameters. On the other hand, a common proper drying temperature could not be identified for acidity (pH), water soluble dry matter and titratable acidity.
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