Characteristics and Process Optimization of Hot-Air Drying Pepper

2012 ◽  
Vol 490-495 ◽  
pp. 3074-3078
Author(s):  
Chun Shan Liu ◽  
Wen Fu Wu ◽  
Jia Song ◽  
Ya Qiu Zhang ◽  
Jun Xing Li ◽  
...  

In order to solve the drying problems in the deep-processing of pepper, peppers were dried through blanching pre-treatment and hot-air drying process. Orthogonal test designs were carried out to investigate factors influencing the quality and moisture content of pepper. The results showed that the whole drying process was a reduction speed drying, hot-air temperature and wind speed have significantly affected on the drying rate of pepper, but the impact of hot-air temperature was more prominent than wind speed; hot-air temperature was found to be the primary parameter to affect the quality of the pepper, wind speed was the secondary one and followed by packing thickness; drying time was found to be the primary parameter to affect the moisture content of the pepper in the drying process, the best drying conditions were as follows: wind temperature was 80°C, wind speed was 10 m/s, packing thickness was 80 cm, drying time was 12 h after 100°C steam blanching pre-treatment

Foods ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 101 ◽  
Author(s):  
Senadeera ◽  
Adiletta ◽  
Önal ◽  
Di Matteo ◽  
Russo

Drying characteristics of persimmon, cv. “Rojo Brillante”, slabs were experimentally determined in a hot air convective drier at drying temperatures of 45, 50, 55, 60, and 65 °C at a fixed air velocity of 2.3 m/s. It was observed that the drying temperature affected the drying time, shrinkage, and colour. Four empirical mathematical models namely, Enderson and Pabis, Page, Logarithmic, and Two term, were evaluated in order to deeply understand the drying process (moisture ratio). The Page model described the best representation of the experimental drying data at all investigated temperatures (45, 50, 55, 60, 65 °C). According to the evaluation of the shrinkage models, the Quadratic model provided the best representation of the volumetric shrinkage of persimmons as a function of moisture content. Overall, higher drying temperature (65 °C) improved the colour retention of dried persimmon slabs.


2011 ◽  
Vol 66-68 ◽  
pp. 573-576
Author(s):  
Chun Shan Liu ◽  
Wen Fu Wu ◽  
Jia Yao ◽  
Ya Qin Li ◽  
Chuang Liu

The purpose of this study is to explore the effecting principle in the drying process. The factors such as hot air temperature, hot air flow, drying time on the grain moisture content have been all investigated. Using UD to establish the optimization mathematics model which making the grain dryer moisture content as the goal of the design, making the factors of hot air flow, drying time, air temperature as parameters, with the help of UD to analysis the effecting principle of the drying process parameters on the grain moisture content, some references have been provided to the tower dryer.


Author(s):  
Luna Shrestha ◽  
Roberto Moscetti ◽  
Stuart Crichton ◽  
Oliver Hensel ◽  
Barbara Sturm

Organic dried apples are common snacks fulfilling functional as well as nutritional aspects. However, appearance of dried slices does not always satisfy consumer requirements, thus, improvements are needed. In this study, partial least squares (PLS) regression models were successfully developed to monitor changes in colour and moisture content in apple slices during the drying process over the Vis/NIR spectral range. The regression vector analysis results suggested that features at 580, 750 and 970 nm are better for predicting moisture content, while 580 and 680 nm allow to measure the (a*/b*) colour ratio.   Keywords: Drying; Dried apple slices; Moisture content; Colour; PLSR modelling


2011 ◽  
Vol 361-363 ◽  
pp. 764-769
Author(s):  
Shu Xing Liu ◽  
Li Li Zhu ◽  
Shu Meng Zhang

A convenient and nutritious dried instant Sargassum fusiforme was developed by the study on the technology of drying with the raw materials of Sargassum fusiforme. The result indicated that the optimum drying technology of Sargassum fusiforme is: on the condition of 95°C for 90s,to blanching, then by means of variable temperature for hot air drying at the 3m/s wind speed, which is air temperature 80°C in first hour,70°C for another 3.5 hours, that we can get high quality Sargassum fusiforme in Rehydration shape,color, and taste .etc.


2012 ◽  
Vol 8 (3) ◽  
Author(s):  
Yoshiki Muramatsu ◽  
Eiichiro Sakaguchi ◽  
Takahiro Orikasa ◽  
Akio Tagawa

Abstract The drying characteristics and volume changes of scarlet runner beans were measured under various conditions to obtain useful basic information for the optimum drying method and conditions. The sample was dried using two drying methods: hot air drying and vacuum drying. The measured changes in moisture content of the sample with the hot air drying process were in good agreement with the exact solution of the infinite plane sheet model. The estimated diffusion coefficients were 3.8×10 -7 -7.4×10 -7 (m 2 h -1) for hot air drying and were related to absolute temperature by an Arrhenius-type equation. The hull of the scarlet runner bean is hard and thick, and the drying rate of the sample was much slower than that of other beans. To establish an efficient drying method without the quality loss, the vacuum drying characteristics of the sample were measured at several levels for temperature and initial moisture content. For the vacuum drying process, an exponential model could be used to estimate the changes in moisture content of the sample. The values of diffusion coefficient for vacuum drying were approximately twice as much as the values of diffusion coefficient for hot air drying at the same temperature. The effects of drying method, temperature, and initial moisture content on the sample quality were investigated, and the optimum drying method and conditions for scarlet runner beans were proposed. Volumetric changes in the sample were determined by measuring particle density. The specific volume of the sample was represented as a linear function of moisture content.


2021 ◽  
Vol 37 (5) ◽  
pp. 763-774
Author(s):  
Ernest Ekow Abano

HighlightsMicrowave pretreatment before drying reduced drying time significantly.Microwave-assisted drying increased the effective moisture diffusivity coefficient.Microwave pretreatment before convective hot-air drying improved quality parameters.The Middili et al. (2002) model best fitted the microwave-assisted drying of sugarloaf pineapples.Abstract. This study’s objective was to provide the optimum drying conditions to produce quality dried sugarloaf pineapples using microwave pretreatments before the conventional hot air drying. For this, the effect of microwave power (385 to 697 W), microwave time (2 to 4 min), and air temperature (50°C to 70°C) on the drying kinetics and quality of sugarloaf pineapple were evaluated using the Box Behnken response surface methodology. To reach a 17.44±0.09% kg/kg dry matter moisture content, we found the optimum drying conditions for sugarloaf pineapples to be 697 W microwave power for 2.26 min before convective hot air drying at a temperature of 64.75°C. The predicted drying time, ascorbic acid content, and browning index were 13.68 h, 20.89 mg/100 g, and 0.099 Abs unit at this optimum condition, respectively. The pineapple slices’ effective moisture removal rate pretreated with microwave before drying was higher than the control and was between 6.42 × 10-10 m2/s and 11.82 × 10-10 m2/s while ones without a microwave were between 3.54 × 10-10 m2/s and 8.78 × 10-10 m2/s for drying at air temperature between 50°C and 70°C. It was discovered that the Midilli et al. (2002) model was the most appropriate thin layer model for microwave-assisted drying of sugarloaf pineapples. The pineapple slices’ drying rate potential generally increased with microwave power and pretreatments time but not the corresponding increase in the air temperature. Drying time for microwave-assisted drying was in the range of 11 to 20 h, while the ones without microwaves were between 18 and 24 h. Therefore, microwaves should be considered a pretreatment step to the industrial production of sugarloaf pineapple to reduce drying time and produce better quality products. Keywords: Drying, Hot air, Microwave, Moisture diffusivity, Sugarloaf pineapple.


Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 202
Author(s):  
Ivan Pavkov ◽  
Milivoj Radojčin ◽  
Zoran Stamenković ◽  
Krstan Kešelj ◽  
Urszula Tylewicz ◽  
...  

This study aimed to determine the effects of osmotic dehydration on the kinetics of hot air drying of apricot halves under conditions that were similar to the industrial ones. The osmotic process was performed in a sucrose solution at 40 and 60 °C and concentrations of 50% and 65%. As expected increased temperatures and concentrations of the solution resulted in increased water loss, solid gain and shrinkage. The kinetics of osmotic dehydration were well described by the Peleg model. The effective diffusivity of water 5.50–7.387 × 10−9 m2/s and solute 8.315 × 10−10–1.113 × 10−9 m2/s was calculated for osmotic dehydration. Hot air drying was carried out at 40, 50, and 60 °C with air flow velocities of 1.0 m/s and 1.5 m/s. The drying time shortened with higher temperature and air velocity. The calculated effective diffusion of water was from 3.002 × 10−10 m2/s to 1.970 × 10−9 m2/s. The activation energy was sensitive to selected air temperatures, so greater air velocity resulted in greater activation energy: 46.379–51.514 kJ/mol, and with the osmotic pretreatment, it decreased to 35.216–46.469 kJ/mol. Osmotic dehydration reduced the effective diffusivity of water during the hot air drying process. It also resulted in smaller shrinkage of apricot halves in the hot air drying process.


Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1309
Author(s):  
Muhammad Heikal Ismail ◽  
Hii Ching Lik ◽  
Winny Routray ◽  
Meng Wai Woo

Fresh rice noodle was usually coated in a large amount of oil to avoid stickiness and extend the shelf life. Pre-treatment has been applied to reduce the quantity of oil in rice noodle. In this research, the pre-treatment and temperature effect on the rice noodle quality subjected to hot air drying, heat pump drying, and freeze drying was investigated. Texture, color, oil content, and starch gelatinization of the dried noodle was further evaluated. Results revealed that there were significant differences (p < 0.05%) in texture, color, oil content, and starch gelatinization in rice noodle subjected to pre-treatment. Furthermore, the texture, color, oil content, and starch gelatinization demonstrated a significant difference (p < 0.05%) in freeze drying rather than hot air drying and heat pump drying. The findings indicate that the qualitative features of the dehydrated noodle are synergistic to pretreatment and drying temperature. Despite superior quality shown by freeze drying, the hierarchical scoring has proven that rice noodle undergoing hot air drying at 30 °C to produce comparable quality attributes. The hierarchical scoring can be a useful tool in quality determination for the food industry.


Sign in / Sign up

Export Citation Format

Share Document