scholarly journals Process optimisation of vacuum drying of onion slices

2011 ◽  
Vol 29 (No. 6) ◽  
pp. 586-594 ◽  
Author(s):  
J. Mitra ◽  
S.L. Shrivastava ◽  
P.S. Rao
Keyword(s):  
Moisture Content ◽  
Numerical Technique ◽  
Colour Change ◽  
Vacuum Drying ◽  
Slice Thickness ◽  
Drying Process ◽  
Rehydration Ratio ◽  
Drying Temperature ◽  
Treated Sample ◽  
Full Factorial

Dehydration of untreated and pre-treated onion slices under vacuum was optimised using the response surface methodology. The effects of the drying temperature (50&ndash;70&deg;C), slice thickness (1&ndash;5 mm), and treatment (5% NaCl and 0.2% K<sub>2</sub>S<sub>2</sub>O<sub>5</sub>) were observed on the responses, viz. final moisture content, colour change, flavour content, and rehydration ratio of the dehydrated onion slices. Full factorial design was employed for the analysis. Optimisation of the vacuum drying process was achieved based on the criteria of maximum flavour retention, 3&ndash;3.5% db moisture content, acceptable colour, and rehydration ratio using numerical technique. The optimum condition for the treated sample was found at 58.66&deg;C drying temperature and 4.95 mm slice thickness. Optimum values of the response parameters, namely the moisture content, colour, flavour content, and rehydration ratio were obtained as 3.5% d.b., 30.33 OI/g dried sample; 4.35 &mu;mol/g dried sample and 4.82, respectively.

scholarly journals Non-enzymatic browning and flavour kinetics of vacuum dried onion slices

2015 ◽  
Vol 29 (1) ◽  
pp. 91-100 ◽  
Author(s):  
Jayeeta Mitra ◽  
Shanker L. Shrivastava ◽  
Pavuluri S. Rao
Keyword(s):  
Moisture Content ◽  
Colour Change ◽  
Enzymatic Browning ◽  
Vacuum Drying ◽  
Rehydration Ratio ◽  
High Quality ◽  
Optical Index ◽  
Hot Air ◽  
Colour Development ◽  
Kinetics Of

Abstract Onion slices were dehydrated under vacuum to produce good quality dried ready-to-use onion slices. Colour development due to non-enzymatic browning and flavour loss in terms of thiosulphinate concentration was determined, along with moisture content and rehydration ratio. Kinetics of non-enzymatic browning and thiosulphinate loss during drying was analysed. Colour change due to non-enzymatic browning was found to be much lower in the case of vacuum dried onion, and improved flavour retention was observed as compared to hot air dried onion slices. The optical index values for non-enzymatic browning varied from 18.41 to 38.68 for untreated onion slices and from 16.73 to 36.51 for treated slices, whereas thiosulphinate concentration in the case of untreated onion slices was within the range of 2.96-3.92 μmol g-1 for dried sample and 3.71-4.43 μmol g-1 for the treated onion slices. Rehydration ratio was also increased, which may be attributed to a better porous structure attained due to vacuum drying. The treatment applied was found very suitable in controlling non-enzymatic browning and flavour loss during drying, besides increasing rehydration ratio. Hence, high quality dried ready- to-use onion slices were prepared.

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.

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%.

Multi-Objective Optimization and Quality Evaluation of Short- and Medium-Wave Infrared Radiation Dried Carrot Slices

2019 ◽  
Vol 15 (8) ◽  
Author(s):  
Qinqin Chen ◽  
Huihui Song ◽  
Jinfeng Bi ◽  
Ruijuan Chen ◽  
Xuan Liu ◽  
...  
Keyword(s):  
Moisture Content ◽  
Infrared Radiation ◽  
Quality Evaluation ◽  
Color Parameter ◽  
Rehydration Ratio ◽  
Carotene Content ◽  
Drying Time ◽  
Drying Temperature ◽  
Hot Air ◽  
Surface Method

AbstractOptimum technology and quality evaluation of short- and medium-wave infrared radiation (SMIR) dried carrot slices were studied. Effects of drying temperature, drying time and infrared power of SMIR drying on the moisture content, color parameter and β-carotene content of dehydrated carrot slices were investigated. The experimental data were well predicted by a modified second-order polynomial model. Drying temperature and drying time had significant effects on moisture content, color parameter and β-carotene content. However, infrared power only showed significant effect on the moisture content. Response surface method (RSM) was used for optimization of SMIR drying of carrot slices, and the optimum condition was found as drying time of 50 min, infrared power of 1125 W, and drying temperature of 70 °C. SMIR dried products were proved to be favorable by comparing with hot-air dried ones due to its higher rehydration ratio (6.89) and β-carotene content (462.48 μg/g).

scholarly journals AKTIVITAS ANTIOKSIDAN DAUN PEGAGAN (Centella asiatica L.Urban) DAN BUNGA KRISAN (Crhysanthemum sp) PADA TIGA VARIASI SUHU PENGERINGAN

2020 ◽  
Keyword(s):  
Antioxidant Activity ◽  
Moisture Content ◽  
Antioxidant Activities ◽  
Block Design ◽  
Centella Asiatica ◽  
Drying Process ◽  
Temperature Variations ◽  
Drying Temperature ◽  
Randomized Block Design ◽  
Positive Results

This research aims to determine the effect of dryer temperature variations on the antioxidant activity of gotu kola leaves and chrysanthemum flowers. The research method used was the experimental method using Randomized Block Design (RBD) with 6 types of treatments and 2 replications. The drying process is carried out until it reaches the moisture content according to SNI for dry tea which is a maximum of 8%. Drying is done using a food dehydrator with three temperature variations (50°C, 55°C and 60°C). The results show that the higher the drying temperature, the faster the standard moisture content is reached. The higher the drying temperature, the weaker antioxidant activity produced. The best antioxidant activity was obtained using the 50°C drying temperature of 36.1 ppm for gotu kola leaf simplicia. While the best antioxidant activity of simplicia of chrysanthemum flowers was obtained at 50°C at 137.99 ppm. The six samples showed positive results on the flavonoid test. Keywords: Antioxidant activities; chrysanthemum flower; gotu kola leaf

scholarly journals Karakteristik Pengeringan Bawang Putih (Allium sativum L) Menggunakan Pengering Oven

2017 ◽  
Vol 2 (1) ◽  
pp. 338-347
Author(s):  
Asmaul Husna ◽  
Rita Khathir ◽  
Kiman Siregar
Keyword(s):  
Moisture Content ◽  
Allium Sativum ◽  
Temperature Treatment ◽  
Drying Process ◽  
Drying Characteristics ◽  
Drying Temperature ◽  
Garlic Powder ◽  
Randomized Design ◽  
Time Required

Abstrak. Penelitian ini bertujuan untuk mengetahui karakteristik pengeringan bawang putih menggunakan pengering oven listrik, menganalisis energi selama proses pengeringan, dan mengkaji mutu bubuk bawang putih. Penelitian ini menggunakan Rancangan Acak Lengkap (RAL) non faktorial dengan perlakuan adalah variasi suhu pengeringan yang terdiri dari tiga taraf pengeringan yaitu suhu 60 °C (A1), 70 °C (A2), dan 80 °C (A3). Hasil penelitian menunjukkan bahwa selama proses pengeringan terjadi penurunan RH, dimana pada suhu 60 0C RH turun dari 64,88 % menjadi 39,59 %, pada suhu 70 0C RH turun dari 82,75 % menjadi 37,77 %, dan pada suhu 80 0C RH turun dari 62,79 % menjadi 36,78 %. Penurunan berat bawang putih terjadi selama proses pengeringan seiring dengan penurunan kadar air bahan. Laju pengeringan meningkat seiring dengan meningkatnya suhu pengeringan. Waktu pengeringan yang dibutuhkan adalah 5 jam (80 °C), 8 jam (70 °C), dan 15 jam (60 °C). Hasil analisis sidik ragam (ANOVA) menunjukkan bahwa perlakuan variasi suhu pengeringan tidak berpengaruh nyata terhadap rendemen bubuk bawang putih, namun berpengaruh nyata terhadap kadar air bubuk bawang putih. Rendemen bubuk bawang putih berada pada kisaran 33,84-34,46%, sedangkan kadar air bubuk bawang putih paling rendah diperoleh pada suhu 70 °C sebesar 2,26%. Persentase kalium tertinggi (1,66%) dan kadar fosfat tertinggi (4,32%) diperoleh pada bubuk bawang putih yang dikeringkan dengan suhu 70 0C. Berdasarkan persepsi panelis, bubuk bawang putih yang dikeringkan dengan suhu 60 0C adalah yang paling disukai. Energi pengeringan tertinggi diperoleh pada pengeringan bawang putih dengan suhu 80 0C yaitu sebesar 813,539 kJ. Drying Characteristics of Garlic (Allium sativum L) Using Oven Dryers Abstract.This study aimed to investigate the drying characteristics of garlic by using electric oven dryer, to analyze the drying energy, and to evaluate the quality of garlic powder produced. This study used a completely randomized design (CRD) non factorial under the drying temperature treatment consisted of three levels that is 60 ° C (A1), 70 ° C (A2), and 80 ° C (A3). The results showed that during the drying process the relative humidity (RH) had been decreased at each drying temperatures observed. The weight loss of garlic occurred during the drying process due to the loss of moisture content which was limited to reach maximum moisture content of 10%. The drying rate had increased as the drying temperature increased. The time required for drying was as long as 5 hours (80 °C), 8 hours (70 °C) and 15 hours (60 °C). Based on the analysis of variance (ANOVA), the variation of drying temperature did not significantly affect the yield of garlic powder, but significantly influenced the moisture content of garlic powder. The yield of garlic powder ranged from 33.84-34.46%, where as the lowest moisture content of garlic powder (2.26%) obtained at drying temperature of 70 °C. The highest potassium (1.66%) and the highest phosphate content (4.32%) were obtained in the garlic powder dried at a temperature of 70 °C. Based on the panelists opinion, garlic powder which is dried at temperature of 60 °C was preferred. The highest drying energy consumed in the drying of garlic at a temperature of 80 °C in the amount of 813.539 kJ.

scholarly journals ANALISA KINERJA MESIN OVEN PENGERING BUAH BERKAPASITAS 1 KG

2020 ◽  
Vol 7 (2) ◽  
pp. 147-155
Author(s):  
Adi Saputra
Keyword(s):  
Moisture Content ◽  
Drying Process ◽  
Drying Time ◽  
Drying Temperature ◽  
Oven Drying ◽  
Dry Fruit

One way to process pineapples, pineapples are classified as highly perishable and rotten foods. For this reason, it is necessary to handle fruit to save the abundance of fruit that occurs during harvest. One example of what the community has done is dealing with the abundant harvest of pineapples by making fruit as a daily snack, namely getting dry fruit products that are ready to eat by making pineapple chips. The production of fruit kiripik is usually done by frying which is done by frying which contains oil which is usually called conventional frying. Therefore, with this oven drying machine, it can help the community in making pineapple chips. The purpose of this study was to determine the moisture content in the manufacture of pineapple chips in a drying oven machine, to analyze the ratio of temperature settings that were set 95 to 110 in the drying process. The fastest drying time is achieved at drying at a drying temperature of 110 ° C.  

scholarly journals Kajian Pengeringan Bak Gabah Secara Intermittent Terhadap Mutu Beras

2020 ◽  
Vol 7 (3) ◽  
pp. 171-178
Author(s):  
Achmad Fitrah Maulidin ◽  
Leopold Oscar Nelwan ◽  
Rokhani Hasbullah
Keyword(s):  
High Temperature ◽  
Moisture Content ◽  
Research Method ◽  
Drying Method ◽  
Drying Process ◽  
Drying Temperature ◽  
Head Rice ◽  
Grain Drying ◽  
Drying Treatment ◽  
High Head

Grain drying with bed dryer is generally effective with high temperatures, but this can increase fissured rice percentage. This can be overcome by combining drying method with tempering. These study were aim to examine drying temperature and duration on bed dryer using intermittent high temperature dryer, and its effect on quality variety of Ciherang with 20-22% moisture content. These research method consists of drying treatment without tempering using 35°C, 60°C and 80°C temperatures to 14% moisture content. Drying treatment with tempering consists of initial drying process-initial tempering-second drying- second tempering or without tempering, where the first drying temperature were 80°C for 20 minutes, 60°C for 30 minutes and second drying temperature were 60 °C and 35°C to 14% moisture content. The tempering duration used was 90 minutes. Results showed the grain drying method without tempering 35°C gave the highest percentage of head rice. However, the use of tempering had significantly reduced cracking and increased head rice percentage compared without tempering at the same temperature. Initial drying of 60°C for 30 minutes-tempering for 90 minutes-drying both temperatures of 35°C to 14% moisture content had been able to produce high head rice and low fissured rice percentage respectively 81.41% and 10%.

Non-Deterministic Description of Wood Radio Frequency Vacuum Drying

Holzforschung ◽  
2003 ◽  
Vol 57 (1) ◽  
pp. 88-94 ◽  
Author(s):  
D. Elustondo ◽  
A. Koumoutsakos ◽  
S. Avramidis
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
Standard Deviation ◽  
Moisture Content ◽  
Radio Frequency ◽  
Western Hemlock ◽  
Vacuum Drying ◽  
Drying Process ◽  
Stochastic Parameters ◽  
Deterministic Description

Summary A numerical method is proposed to predict the stochastic dispersion of data that unavoidably occurs in a real drying process. The method is based on the use of discrete frequency distribution curves to predict a random variation on some parameters of the process and is applied to the case of radio frequency vacuum (RFV) drying of wood. Experimental data of RFV drying of western hemlock timbers were used to obtain the numeric values of the stochastic parameters and their standard deviation. A mathematical model was designed to simulate the final moisture content dispersion on hypothetical examples. Results were quantified using three indices: average, range and standard deviation.

Hot Air Drying and Vacuum Drying Characteristics of Scarlet Runner Beans

2012 ◽  
Vol 8 (3) ◽  
Author(s):  
Yoshiki Muramatsu ◽  
Eiichiro Sakaguchi ◽  
Takahiro Orikasa ◽  
Akio Tagawa
Keyword(s):  
Diffusion Coefficient ◽  
Moisture Content ◽  
Initial Moisture Content ◽  
Vacuum Drying ◽  
Drying Method ◽  
Drying Process ◽  
Hot Air Drying ◽  
Air Drying ◽  
Drying Characteristics ◽  
Hot Air

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.

Sign in / Sign up

Export Citation Format

Share Document