scholarly journals Effect of drying temperature on the content and composition of hop oils

2018 ◽  
Vol 64 (No. 10) ◽  
pp. 512-516 ◽  
Author(s):  
Rybka Adolf ◽  
Krofta Karel ◽  
Heřmánek Petr ◽  
Honzík Ivo ◽  
Pokorný Jaroslav
Keyword(s):  
Moisture Content ◽  
Essential Oils ◽  
Experimental Chamber ◽  
Drying Time ◽  
Drying Temperature ◽  
Different Temperatures ◽  
Traditional Manner

In terms of content, the paper is aimed at analysing and comparing the quality of fresh green hops and hops dried at two drying temperatures – 55°C (in the traditional manner) and 40°C (using the so-called gentle drying), regarding the maximum preservation of hop essential oils. Comparative experiments were carried out in an experimental chamber dryer with two Czech hop cultivars Saaz and Harmonie. The moisture content of hops at the beginning of drying was 75% and at the end of drying it was 9–10%. By lowering the drying temperature from 55°C to 40°C, the drying time in cv. Saaz prolonged from 8 to 10 h and for the cv. Harmonie from 9 h to 12 h. Compared to fresh hops, the amount of hop oils decreased by 10% when dried at 40°C and by 36% (cv. Saaz) and 43% (cv. Harmonie) when dried at 55°C. These losses can be considered significant, especially for hops intended for late and dry beer hopping. However, by drying the hops at different temperatures, the ratios between various components of the essential oils and thus also their sensory character remained approximately unchanged. Due to the reduced amount of essential oils, the drying effect reduces the intensity of hop aroma depending on the drying temperature.

scholarly journals INFLUENCE OF DRYING TEMPERATURE AND PULP LAYER THICKNESS ON THE PHYSICAL AND PHYSICOCHEMICAL QUALITY OF PEQUI POWDER1

2021 ◽  
Vol 34 (4) ◽  
pp. 945-956
Author(s):  
ELISABETE PIANCÓ DE SOUSA ◽  
DANIELLE MARTINS LEMOS ◽  
ROSSANA MARIA FEITOSA DE FIGUEIREDO ◽  
JOSIVANDA PALMEIRA GOMES ◽  
ALEXANDRE JOSÉ DE MELO QUEIROZ
Keyword(s):  
Moisture Content ◽  
Layer Thickness ◽  
Water Activity ◽  
Physicochemical Characterization ◽  
Convective Drying ◽  
Drying Time ◽  
Drying Temperature ◽  
Different Temperatures ◽  
Gab Model ◽  
Fresh Pulp

ABSTRACT The objective of this work was to characterize the physical and physicochemical parameters of pequi powders obtained by means of convective drying at different temperatures (50, 60, 70 and 80 °C) and pulp layer thicknesses (0.5, 1.0 and 1.5 cm). Initially, the physicochemical characterization of fresh pulp was carried out, followed by convective drying under the conditions mentioned, until the equilibrium moisture content and subsequent disintegration to obtain the powders. Subsequently, the physical and physicochemical properties of the obtained powders were analyzed and the best powder was selected based on reduced moisture content and water activity and lower peroxide index. Pequi pulp showed a high fat content and a yellowish color; with the increase in drying temperature, there were reductions in the moisture content, water activity and protein content of the powders. As for the color parameters, the powder showed a darkening with the increase in drying time; the water adsorption isotherms of the selected pequi powder were classified as Type II, and the GAB model showed the best fits. The pequi powders showed good solubility and low cohesiveness. The powder that showed good flowability was produced at a drying temperature of 60 °C and with pequi pulp layer thickness of 0.5 cm.

scholarly journals Cherry Tomato Drying: Sun versus Convective Oven

Horticulturae ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 40
Author(s):  
Vincenzo Alfeo ◽  
Diego Planeta ◽  
Salvatore Velotto ◽  
Rosa Palmeri ◽  
Aldo Todaro
Keyword(s):  
Moisture Content ◽  
Initial Moisture Content ◽  
Drying Process ◽  
Drying Time ◽  
Oven Drying ◽  
Sun Drying ◽  
Different Temperatures ◽  
Final Water Content ◽  
Drying Curves ◽  
Drying Conditions

Solar drying and convective oven drying of cherry tomatoes (Solanum lycopersicum) were compared. The changes in the chemical parameters of tomatoes and principal drying parameters were recorded during the drying process. Drying curves were fitted to several mathematical models, and the effects of air temperature during drying were evaluated by multiple regression analyses, comparing to previously reported models. Models for drying conditions indicated a final water content of 30% (semidry products) and 15% (dry products) was achieved, comparing sun-drying and convective oven drying at three different temperatures. After 26–28 h of sun drying, the tomato tissue had reached a moisture content of 15%. However, less drying time, about 10–11 h, was needed when starting with an initial moisture content of 92%. The tomato tissue had high ORAC and polyphenol content values after convective oven drying at 60 °C. The dried tomato samples had a satisfactory taste, color and antioxidant values.

scholarly journals Development of Black Pepper Rotary Drum Dryer System

2020 ◽  
Vol 12 (7) ◽  
Author(s):  
Ana Sakura Zainal Abidin ◽  
◽  
Mohamad Zulhatta Kifli ◽  
Annisa Jamali ◽  
Rasli Muslimen ◽  
...  
Keyword(s):  
Moisture Content ◽  
Heating Temperature ◽  
Chemical Properties ◽  
Practical Method ◽  
Black Pepper ◽  
Drying Time ◽  
Final Weight ◽  
Rotary Drum ◽  
Current Weight

Rotary drum dryer has been identified as hygienic and practical method to dry black pepper. The quality of black pepper is defined based on the chemical properties and moisture content. This research aims to develop a control system for black pepper rotary drum dryer. The dried pepper should meet the specific 12% moisture content while the heating temperature must be kept below 550C. The requirement of 12% moisture content is equivalent to 30% of the remaining weight of the pepper (final weight). The developed system uses Arduino Mega 2560 REV board as a microcontroller. A type K thermocouple with MAX6675 thermocouple amplifier and S-type load cells (TAS501) with HX711 load cell amplifier are used as input sensor to microcontroller. The system keeps measuring the current weight until it hit the targeted final weight. Two set of experiments that are using 500 g and 1500 g of pre-treated pepper were conducted to verify the system. As a result, the dryer was successful to work within the desired temperature and it stop operating just after the samples reached 12% of the moisture content. The finding has proven a shorten of drying time from 4 to 7 days when using the traditional method to the current 3 – 5 hours only when using the developed system. Hence, this is an improved method achieved to a quick drying of the black pepper.

scholarly journals Physiological and sensorial quality of Arabica coffee subjected to different temperatures and drying airflows

2017 ◽  
Vol 39 (2) ◽  
pp. 225 ◽  
Author(s):  
Guilherme Euripedes Alves ◽  
Flávio Meira Borém ◽  
Eder Pedroza Isquierdo ◽  
Valdiney Cambuy Siqueira ◽  
Marcelo Ângelo Cirillo ◽  
...  
Keyword(s):  
Germination Percentage ◽  
Drying Kinetics ◽  
Drying Rate ◽  
Drying Time ◽  
Physiological Variables ◽  
Different Temperatures ◽  
Negative Effect ◽  
Physiological Quality ◽  
Sensorial Quality

The objective of this study was to evaluate the correlation between a group of physiological variables (electrical conductivity, potassium leaching, and germination percentage) and a group of drying kinetics variables (drying time and drying rate) in addition to verifying the relation between drying kinetics variables and coffee quality as a function of processing type, temperature, and drying airflow. Coffee drying was conducted in a fixed-layer dryer at two temperatures and two airflows. After drying, an evaluation of the physiological and sensorial quality was conducted. Based on the results obtained, the following conclusions were drawn: coffee that is processed via a dry method is more sensitive to mechanical drying with heated air than coffee processed via a wet method, resulting in poor physiological performance; airflow does not interfere with the physiological quality of pulped and natural coffees; a temperature increase from 40 to 45°C resulted in a decrease in the physiological quality only for pulped coffee; and an increase in the drying rate as a result of an increase in the drying temperature to 40°C had a negative effect on the sensorial quality of pulped coffee. 

scholarly journals Influence of Different Hot Air Drying Temperatures on Drying Kinetics, Shrinkage, and Colour of Persimmon Slices

Foods ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 101 ◽  
Author(s):  
Senadeera ◽  
Adiletta ◽  
Önal ◽  
Di Matteo ◽  
Russo
Keyword(s):  
Moisture Content ◽  
Quadratic Model ◽  
Drying Process ◽  
Air Velocity ◽  
Hot Air Drying ◽  
Drying Time ◽  
Air Drying ◽  
Drying Characteristics ◽  
Drying Temperature ◽  
Hot Air

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.

Comparison of Drying Kinetics of Maize in Oven and in Pilot Silo Dryer: Influence on Moisture Content and Physical Characteristics

2016 ◽  
Vol 12 (6) ◽  
pp. 599-606 ◽  
Author(s):  
Flávia Daiana Montanuci ◽  
Raphaela Mulato Cavalcante ◽  
Camila Augusto Perussello ◽  
Luiz Mario de Matos Jorge
Keyword(s):  
Moisture Content ◽  
Temperature Increase ◽  
Drying Kinetics ◽  
Final Moisture Content ◽  
Drying Rate ◽  
Drying Time ◽  
Drying Temperature ◽  
Design And Optimization ◽  
Process Kinetics ◽  
Kinetics Of

Abstract The study of process kinetics may aid the design and optimization of drying systems. This paper evaluated the influence of drying temperature (40, 60 and 80 °C) on the moisture content, drying rate, density, shrinkage and breakage of maize dried in two different dryers: oven and silo dryer. In both dryers, the temperature increase reduced drying time, final moisture content and shrinkage of the grains, however increased breakage. Drying rate was higher in the oven (6.4×10−4±2.3×10−4s−1 versus 5.4×10−4±1.2×10−4s−1), while shrinkage (15.2±4.7 % versus 24.4±5.6 %) and density increase (16.6±5.9 % versus 33.4±5.8 %) were more intense in the silo. There was a large release of husk in the silo dryer and the moisture content was slightly smaller in the lower layers respective to the upper ones.

scholarly journals Kajian Pengering Kopi Gayo Semi Basah Menggunakan Alat Pengering Tipe Hohenheim

2020 ◽  
Vol 4 (4) ◽  
pp. 362-371
Author(s):  
Antoni Hardi ◽  
Ichwana Ichwana ◽  
Rita Khathir
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Water Content ◽  
Drying Process ◽  
Arabica Coffee ◽  
Drying Temperature ◽  
Average Daily Temperature ◽  
Coffee Beans ◽  
Simple Technology

Abstrak. Sebagai produsen kopi Arabica, masyarakat Gayo terkendala pada suhu lokal di Aceh Tengah yang relatif dingin dan teknologi sederhana yang digunakan untuk proses pengeringan kopi. Suhu rata-rata harian adalah 23-29°C. Bahan yang digunakan pada penelitian ini yaitu biji kopi yang diolah dengan metode semi basah sebanyak 9kg. Parameter penelitian meliputi suhu pengeringan, kelembaban relatif, kadar air dan rendemen. Hasil penelitian menunjukkan bahwa suhu pengeringan menggunakan alat pengering Hohenheim jauh lebih tinggi sekitar 10-20°C dari suhu pengeringan secara penjemuran. Proses pengeringan kopi labu sampai bisa digiling membutuhkan waktu selama 12 jam yaitu 8 jam pada hari pertama dan 4 jam pada hari ke-2. Sedangkan proses pengeringan tahap 2 membutuhkan waktu selama 16 jam sampai menghasilkan kopi beras dengan kadar air 9,32%. Kualitas kopi beras yang dihasilkan sudah baik dengan kadar air  yang sudah memenuhi standar SNI, tidak berbau busuk, dan tidak terkontaminasi. Nilai rendemen kopi beras berbasis kopi labu adalah 35%.Study of Drying Semi Washed Gayo Coffee Use Dryer Type Hohenheim Abstrack. As an Arabica coffee producer, the Gayo community is constrained by the relatively cold local temperatures in Central Aceh and the simple technology used for the coffee drying process. The average daily temperature is 23-29 ° C. The material used in this study was coffee beans which were processed by the semi-wet method of 9kg. Research parameters include drying temperature, relative humidity, moisture content and yield. The results showed that the drying temperature using a Hohenheim dryer is much higher around 10-20 ° C than the drying temperature by drying. The process of drying pumpkin coffee until it can be ground needs 12 hours, which is 8 hours on the first day and 4 hours on the second day. While the process of drying stage 2 takes 16 hours to produce rice coffee with a moisture content of 9.32%. The quality of rice coffee produced is good with water content that meets SNI standards, does not smell bad, and is not contaminated. The yield of pumpkin coffee-based rice coffee is 35%.

scholarly journals Drying characteristics and quality evaluation in convective drying of Cissus quadrangularis Linn.

2018 ◽  
Vol 192 ◽  
pp. 03041
Author(s):  
Setthawat Thanimkarn ◽  
Ekkapong Cheevitsopon ◽  
Jiraporn Sripinyowanich Jongyingcharoen
Keyword(s):  
Quality Evaluation ◽  
Moisture Diffusivity ◽  
Convective Drying ◽  
Total Phenolic ◽  
Drying Time ◽  
Drying Characteristics ◽  
Drying Temperature ◽  
Cissus Quadrangularis ◽  
Lower Bulk Density

This study aimed to investigate the effect of drying temperature (40, 60, 80, and 100°C) on drying characteristics of Cissus quadrangularis Linn. (CQ) undergoing convective drying. Physical properties and phytochemicals of the dried CQ were also evaluated. CQ with the thickness of 5 mm was dried from about 10 to 0.1 g water/g dry matter. The results showed that increasing drying temperature increased drying rate (DR) and effective moisture diffusivity (Deff) and consequently decreased drying time. The drying time, maximum DR, and Deff were in the ranges of 85-1920 min, 0.0059-0.0248 g water/g dry matter·min, and 0.7302-9.1281×10-9 m2/s, respectively. Lower drying temperature could preserve quality of the dried CQ. Decreasing drying temperature resulted in greener and lower bulk density and shrinkage. The greatest total phenolic content (TPC) and quercetin content were obtained by drying the CQ at 60°C.

scholarly journals Changes in Microbiological and Physicochemical Quality of Dried Persimmons (Diospyros kaki Thunb.) Stored at Various Temperatures

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Jeong-Eun Hyun ◽  
Ji-Yeon Kim ◽  
Eun-Mi Kim ◽  
Jong-Chan Kim ◽  
Sun-Young Lee
Keyword(s):  
Moisture Content ◽  
Shelf Life ◽  
Color Index ◽  
Visual Quality ◽  
Microbial Populations ◽  
Diospyros Kaki ◽  
Visual Appearance ◽  
Different Temperatures ◽  
Yeasts And Molds

This study was conducted to investigate the microbiological, physicochemical, and visual quality of dried persimmons (Diospyros kaki Thunb. cv. Cheongdo-Bansi) during storage at various temperatures in order to determine the shelf-life. Two commercial dried persimmon samples were evaluated for changes in weight, moisture content, color, texture (hardness and gumminess), and microbial populations during storage at different temperatures (−20, 5, 12, and 25°C) for 70 days. Overall, dried persimmon-2 showed lower levels of total mesophilic bacteria, Escherichia coli, coliforms, yeasts, and molds than dried persimmon-1. Among the physicochemical qualities, significant differences were observed in color parameters such as L∗, a∗, and b∗ of the dried persimmons. However, no significant differences in weight, moisture content, and texture were observed in dried persimmons during storage for 70 days. Thus, changes in visual appearance and color index such as chroma value and browning index can be used as indicators for determining the shelf-life of dried persimmons.

Influence of Osmotic Agent Concentration and Drying Temperature on the Osmotic Dehydration of Pomelo

2012 ◽  
Vol 554-556 ◽  
pp. 1466-1469
Author(s):  
Sirasa Jengsooksawat ◽  
Sawanit Aichayawanich
Keyword(s):  
Moisture Content ◽  
Sucrose Solution ◽  
Osmotic Dehydration ◽  
Solution Concentration ◽  
Experimental Procedure ◽  
Drying Temperature ◽  
Dehydration Rate ◽  
Sucrose Solutions ◽  
Osmotic Agent

This research aimed to study on the optimum condition for osmotic dehydration of pomelo. The experimental procedure was divided into 2 sections. For first section, the effect of sucrose solution concentration (50, 60, and 70 oBrix) on osmotic rate and moisture content of osmotic dehydrated pomelo were evaluated. After that, the effects of drying temperature (50, 65, and 80oC) on quality of osmotic dehydrated pomelo including, odor, texture, taste, and color were determined. The experimental results showed that the osmotic dehydration rate of pomelo were 6.4, 9.4, and 9.6 oBrix/hr when the pomelo was immersed in 50, 60, and 70 oBrix sucrose solutions, respectively. The moisture content of osmotic dehydrated pomelo which immersed in 70oBrix was lowest. The osmotic dehydrated pomelo that was immersed in 70 oBrix sucrose solutions and dried at 50oC has highest quality.

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