Search results

1 – 10 of over 25000
To view the access options for this content please click here
Article
Publication date: 31 August 2021

Osman İsmail and Özlem Gökçe Kocabay

The aim of this work was to study the effect of the different temperatures on drying kinetics and quality parameters of vacuum oven-dried mediterranean or black mussel …

Abstract

Purpose

The aim of this work was to study the effect of the different temperatures on drying kinetics and quality parameters of vacuum oven-dried mediterranean or black mussel (Mytilus galloprovincialis) specimens.

Design/methodology/approach

Drying process was performed at 50, 60 and 70 °C and a vacuum drying pressure of 0.1 kPa. The proximate composition analysis was done. Drying rates of the mussels were computed. Mathematical modeling was carried out. Effective moisture diffusivity, activation energy and total energy consumption were calculated. Color measurement was conducted.

Findings

Drying took place entirely in the falling rate period. The obtained results indicated that the drying air temperature has a remarkable influence on the moisture content and drying rate. Drying resulted in a significant increasing of protein and fat content. The Deff values ranged from 1.44 × 10−9–3.23 × 10−9 m2/s, with the activation energy 4.47 kW kg−1. The Alibas model is the most proper model to define the drying curves. This method provided high energy efficiency and quality in dried products.

Research limitations/implications

Fresh mussels grown in Eceabat location were used as the study sample. In the drying process, 50, 60, 70 °C temperatures and 0.1 kPa pressure was used. These are the limitations of the research.

Originality/value

This work is the first to report the influence of vacuum oven drying on the color changes and drying kinetics of black mussels.

Details

British Food Journal, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0007-070X

Keywords

To view the access options for this content please click here
Article
Publication date: 19 August 2021

B. Norerama D. Pagukuman and M. Kamel Wan Ibrahim

The purpose of this paper is to present and discuss the external factors of the solar dryer design that influenced the thermal efficiency of the solar dryer that…

Abstract

Purpose

The purpose of this paper is to present and discuss the external factors of the solar dryer design that influenced the thermal efficiency of the solar dryer that contribute to the better quality of dried food products.

Design/methodology/approach

From the reviewed works of literature, the external factors including the drying temperature, airflow rate and relative humidity have significant effects to increase the rate of moisture diffusivity of the freshly harvested products during the drying process. The proper controls of airflow rate (Q), velocity (V), relative humidity (RH%) and drying temperature (°C) can influence the dried product quality. The dehydration ratio is the procedure to measure the quality of the dried food product.

Findings

The indirect solar dryer including the mixed-mode, hybrid and integrated was found shorter in drying time and energy-intensive compared to sun drying and direct drying. The recommended drying temperature is from 35.5°C to 70°C with 1–2 m/s velocity and 20%–60% relative humidity. The optimum thermal efficiency can be reached by additional devices, including solar collectors and solar accumulators. It gives a simultaneous effect and elongated the drying temperature 8%–10% higher than ambient temperature with 34%–40% energy saving. The recommended airflow rate for drying is 0.1204 to 0.0894 kg/s. Meanwhile, an airflow rate at 0.035–0.04 kg/m2 is recommended for an optimum drying kinetic performance.

Research limitations/implications

This paper discusses the influence of the external factors of the solar dryer design on the thermal performance of the solar dryer and final dried food products quality. Therefore, the findings cannot serve as a statistical generalization but should instead be viewed as the quantitative validation subjected to fundamentals of the solar dryer design process and qualitative observation of the dried food product quality.

Practical implications

A well-designed of solar dryer with low operating and initial fabrication cost, which is simple to operate is useful for the farmers to preserve surplus harvested crops to an acceptable and marketable foods product. The optimization of the external and internal factors can contribute to solar dryer thermal performance that later provides an organoleptic drying condition that results in good quality of dried product and better drying process. The recommended drying temperature for a drying method is between 35°C up to 70°C. Drying at 65.56°C was effective to kill microorganisms. Meanwhile, drying at 50°C consider as average drying temperature. The recommended airflow rate for drying is 0.1204 to 0.0894 kg/s. Meanwhile, air flowrate at 0.035–0.04 kg/m2 is recommended for optimum drying kinetic performance. The recommended value of aspect ratio and mass flow rate is 200 to 300 for an optimum evaporation rate. The good quality of dried products and good performance of solar dryers can be developed by proper control of airflow rate (Q), velocity (V), relative humidity (RH%) and drying temperature (°C).

Social implications

The proper control of the drying temperature, relative humidity and airflow rate during the drying process will influence the final dried food products in terms of shape, color, aroma, texture, rupture and nutritious value. It is crucial to control the drying parameters because over-drying caused an increment of energy cost and reduces the dry matter. The quick-drying will disturb the chemical process during fermentation to be completed.

Originality/value

This study identifies the potential of the solar drying method for dehydrating agricultural produces for later use with the organoleptic drying process. The organoleptic drying process can reduce mold growth by promising an effective diffusion of moisture from freshly harvested products. The research paper gives useful understandings that well-designed solar drying technology gives a significant effect on dried product quality.

Details

Journal of Engineering, Design and Technology , vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1726-0531

Keywords

To view the access options for this content please click here
Article
Publication date: 11 September 2007

V. Dunkwal, S. Jood and S. Singh

This article aims to focus on the food value of the mushroom. Because of its low calorific value and very high content of proteins, vitamins and minerals, mushrooms may…

Abstract

Purpose

This article aims to focus on the food value of the mushroom. Because of its low calorific value and very high content of proteins, vitamins and minerals, mushrooms may contribute significantly in overcoming protein deficiency in developing countries like India.

Design/methodology/approach

Oyster (Pleurotus sajor caju) mushroom cultivated on two substrates i.e. wheat straw and brassica straw were procured. Freshly harvested and washed mushrooms were cut into small pieces. Sliced mushrooms were divided into four portions. Two portions were left untreated and dried using sun and oven drying methods. The third portion was blanched in boiling water at 100 °C for two mins, cooled immediately and drained. The blanched samples were divided into two portions. One portion was sun dried and another was oven dried. The fourth portion was soaked in solution of citric acid (0.25 percent) for 30 mins and drained. The steeped samples were divided into two portions. One portion was sun dried and another was oven dried. Each sample was dried from initial moisture content of 91 percent on fresh weight basis of the final moisture content 10 percent on dry weight basis. All the samples were ground to make fine powder. The untreated and treated samples were analysed for physico‐chemical properties and sensory evaluation by using standard methods.

Findings

Treated and untreated powders prepared from oyster (Pleurotus sajor caju) mushrooms grown on two substrates i.e. wheat and brassica straw were analysed for physical and chemical characteristics. Among the powders, T6 (steeped in 0.25 percent citric acid and oven dried) powder exhibited highest yield followed by untreated and blanched powders. On the other hand, untreated samples T1 (sun dried) and T4 (oven dried) showed higher browning index as compared to pretreated powders. Steeped samples (T3 and T6) from both type of mushrooms, irrespective of drying methods exhibited higher values of water retention capacity and swelling index as well as sensory attributes (colour, aroma and texture) In terms of chemical analysis, steeped samples from both types of mushrooms, irrespective of drying methods, exhibited higher contents crude protein, crude fibre and ash as compared to blanched powders. Blanching in hot water may cause leaching out of nutrients.

Practical implications

With regard to healthy benefits and medicinal value of mushroom, its production and consumption should be increased. However, mushroom production does not demand land, but helps in the bioconversion of potential pollutants like agro‐wastes to useful and nutritive food for human consumption, which is essential to a developing country like India.

Originality/value

The findings of this article may contribute significantly in overcoming protein deficiency in developing countries like India. Mushrooms have a low carbohydrate content, no cholesterol and are almost fat free. Therefore, they form an important constituent of a diet for a population suffering from atherosclerosis.

Details

British Food Journal, vol. 109 no. 9
Type: Research Article
ISSN: 0007-070X

Keywords

To view the access options for this content please click here
Article
Publication date: 21 March 2008

V. Šťáva, D. Veselý and P. Kalenda

To study the drying effects of cobalt, manganous and mixed salts for their catalytic action in cross linking reactions occurring during the creation of an alkyd resin film.

Abstract

Purpose

To study the drying effects of cobalt, manganous and mixed salts for their catalytic action in cross linking reactions occurring during the creation of an alkyd resin film.

Design/methodology/approach

The driers of Co‐octoate, Mn‐octoate, Mn‐octoate with an active organic ligand, and mixed drier containing the salts of Mn, Ca, and Zn were employed in the cross linking reactions of alkyls. The study verified the possibility of using manganese as an active cation in catalytic curing reactions. The course of the cross‐linking of alkyds was monitored on a model system of the reactions of drier with ethyl linoleate, using FTIR spectroscopy. Reaction‐rate constants corresponding to the first phase of cross linking were obtained. The driers under scrutiny were used to identify the time of the drying of alkyd resin modified with flax oil. The final phase of the cross linking reactions was monitored by means of measurement the hardness of the created alkyd film depending on time.

Findings

The driers under scrutiny were found to have catalytic effects in auto‐oxidation reactions. Very high efficiency was found with all of the driers. The highest efficiency was found with Co‐octoate resulting in the development of the highest hardness of coatings. Mn‐octoate and mixed driers show a steeper increase in film hardness than Co‐drier, yet the final films are suppler.

Practical implications

The driers studied can be conveniently used to accelerate creation of alkyd coatings modified with natural oils and designed for both industrial and decorative purposes.

Originality/value

The method of identifying the kinetic parameters of the cross‐linking reactions of alkyds is relatively new and facilitates the localisation of driers that are optimum for specific paints formulations. Of benefit is also the study of Mn‐driers that are more environmentally acceptable than Co‐driers.

Details

Pigment & Resin Technology, vol. 37 no. 2
Type: Research Article
ISSN: 0369-9420

Keywords

To view the access options for this content please click here
Article
Publication date: 1 March 1977

James G. Brennan

Drying of food for the purpose of preservation is by no means a modern idea. Although its origins are not clear it is known that for many thousands of years man has used…

Abstract

Drying of food for the purpose of preservation is by no means a modern idea. Although its origins are not clear it is known that for many thousands of years man has used sun‐dried fruits and vegetables to sustain him in off‐season periods. Sun‐dried dates, figs and apricots were used by the aboriginal inhabitants of the Mediterranean Basin and the Near East. A dried product prepared from potato was used by the inhabitants of the Andean Highlands up to three thousand years ago. Dried venison or buffalo meat, known as pemmican, was prepared by the American Indians before the arrival of Columbus. Drying of vegetables by artificial means was first reported in Britain in the Eighteenth century. Quantities of dried vegetables were used by the British troops in the Crimean War, by Union troops in the American Civil War and in many other early campaigns and expeditions. Dehydration of fruit by artificial means began towards the end of the nineteenth century in America.

Details

Nutrition & Food Science, vol. 77 no. 3
Type: Research Article
ISSN: 0034-6659

To view the access options for this content please click here
Article
Publication date: 1 April 2003

L. Higgins, S.C. Anand, M.E. Hall and D.A. Holmes

The length and width shrinkages, skewness, spirality and moisture content of three weft knitted cotton structures, plain single jersey, interlock and lacoste, were…

Abstract

The length and width shrinkages, skewness, spirality and moisture content of three weft knitted cotton structures, plain single jersey, interlock and lacoste, were determined at regular intervals during tumble drying. Significant length and width shrinkages occurred in all three structures with the amount of shrinkage increasing rapidly in plain single jersey and lacoste as their moisture contents fell below 30 per cent. Distortion was less affected by tumble drying. An attempt was made to isolate the effects of heat and agitation during tumble drying. It has been demonstrated that similar patterns of shrinkage and distortion occur whether heat is applied during tumble drying or not. The tumbling action in a tumble drier has the greatest influence on the dimensional stability and distortion of weft knitted cotton fabrics.

Details

International Journal of Clothing Science and Technology, vol. 15 no. 2
Type: Research Article
ISSN: 0955-6222

Keywords

To view the access options for this content please click here
Article
Publication date: 1 February 2002

K. Murugesan, H.R. Thomas and P.J. Cleall

A numerical study is carried out to investigate the influence of multistage drying regimes on the drying kinematics of a porous material. In particular the effects of…

Abstract

A numerical study is carried out to investigate the influence of multistage drying regimes on the drying kinematics of a porous material. In particular the effects of varying the conditions of the drying medium are studied. The drying model for the solid is developed based on the continuum approach. A series of simulations of the drying behaviour of a rectangular brick with varying temperature, heat transfer coefficient and relative humidity of the drying medium are undertaken. It is found that the total drying time is mainly dependent on the relative humidity of the drying medium. Also condensation is predicted on the surface of the brick, with the quantity of condensation being directly linked to the relative humidity and temperature of the drying medium. Overall it is concluded that multistage drying regimes are useful in reducing the overall drying time whilst avoiding detrimental shrinkage during the constant drying period.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 12 no. 1
Type: Research Article
ISSN: 0961-5539

Keywords

To view the access options for this content please click here
Article
Publication date: 24 May 2011

Elizabeth Oluwaseun Sunny‐Roberts and Dietrich Knorr

This paper aims to evaluate the cellular injuries associated with spray‐drying of Lactobacillus rhamnosus GG (LGG) in trehalose/monosodium glutamate (MSG) media by means…

Abstract

Purpose

This paper aims to evaluate the cellular injuries associated with spray‐drying of Lactobacillus rhamnosus GG (LGG) in trehalose/monosodium glutamate (MSG) media by means of flow cytometry measurements; and also whether, and to what extent, the probiotic remain stable and viable in food formulations.

Design/methodology/approach

Spray‐drying was applied in the production of trehalose‐based preparations containing LGG. To gain more insights on the cellular damages that must have occurred during drying, flow cytometric analysis was applied in combination with carboxyfluorescein diacetate (cFDA) and PI stains. Spray‐dried samples were observed by scanning electron microscopy (SEM). The storage stability of spray‐dried LGG was monitored in food samples over a period of time.

Findings

It was observed that during spray‐drying, 1.80×109 CFU/ml viable counts, which were equivalent of 68.8 per cent cells, were recovered in trehalose matrices but on incorporating 12.5 g/l MSG as a carrier component, survival rates were significantly improved. Density plot analysis showed a higher degree of membrane damage in cells spray‐dried in trehalose without MSG. SEM revealed no difference in the shapes and surfaces of spray‐dried samples. Evaluation of the recovery rates of LGG, initial count of ∼109 CFU/ml or g, at storage time intervals revealed a minimum level of ∼105 CFU/ml in apple juice after 12 days and ∼107 CFU/g in chocolate beverages after ten weeks.

Originality/value

The potential contribution of MSG as a carrier component with trehalose in preventing higher losses during spray‐drying and food storage is pointed out in this study.

Details

Nutrition & Food Science, vol. 41 no. 3
Type: Research Article
ISSN: 0034-6659

Keywords

To view the access options for this content please click here
Article
Publication date: 14 September 2010

A. Kalendová, D. Veselý and P. Kalenda

The paper aims to investigate the drying effect exhibited by pigments combined with a Co(II) salt of 2‐ethylhexanoic acid (Co(II)) in an alkyd resin modified by soya bean oil.

Abstract

Purpose

The paper aims to investigate the drying effect exhibited by pigments combined with a Co(II) salt of 2‐ethylhexanoic acid (Co(II)) in an alkyd resin modified by soya bean oil.

Design/methodology/approach

Paint hardening was studied by means of a method that follows the progress of alkyd film drying. Another important method was employed to monitor the gradually increasing hardness of the drying films. Hardness of thin films was measured by the Persos method. ZnO, ZnO nanoparticles, V2O5, ZnS and TiO2 were used to study the effect of solid inorganic pigments on alkyd film drying. The pigment particles were characterised by scanning electron microscopy. The investigated pigments were combined with a constant amount of the Co(II) drier that acts in the system as a homogeneous catalyst, while the investigated pigments played the role of heterogeneous catalysts.

Findings

Using certain pigments as catalysts in drying, alkyd resins brings about new findings concerning the function of fillers and pigments in paint films. ZnO nanoparticles substantially accelerate film drying and moreover, the resulting films exhibit substantially higher hardness than films containing other inorganic pigments. To prepare films exhibiting higher hardness within a shorter time, one may also use ZnO microparticles or ZnS. TiO2 and V2O5 were identified as pigments that either do not take part in the drying process or reduce the hardness of the resulting film.

Practical implications

The investigated catalytic system pigment/Co(II) drier can be advantageously used to accelerate the formation of alkyd paints modified by natural oils both for industrial and decorative purposes. It was established that hardness of paint films containing ZnO nanoparticles is twice as high as that of films containing only the Co(II) drier without any pigment. This finding makes new applications of alkyd paints possible in all instances where higher hardness is required.

Originality/value

Considering pigments as heterogeneous catalysts in systems producing films by the oxypolymerising mechanism is a new approach that gives rise to new and original solutions.

Details

Pigment & Resin Technology, vol. 39 no. 5
Type: Research Article
ISSN: 0369-9420

Keywords

To view the access options for this content please click here
Article
Publication date: 3 October 2016

Fahim Ullah, Min Kang, Lubna Hassan, Ninghui Li, Jun Yang, Xingsheng Wang and Mansoor Khan Khattak

The purpose of the study was to develop a performance flat-plate solar collector that would be used as a solar drier for fruit fig (Ficus carica L). This study proposes…

Abstract

Purpose

The purpose of the study was to develop a performance flat-plate solar collector that would be used as a solar drier for fruit fig (Ficus carica L). This study proposes how and why solar energy is important for drying the agricultural products. This study aims to expand the domain of solar collector for different purposes and, most important, for agricultural resource normally found in the literature.

Design/methodology/approach

The paper opted for an exploratory study using the flat-plate solar collector with drying chamber for drying purposes of agricultural products. During the experiment, the data were collected with moisture content, drying rate of the product and solar irradiation falls on the collector.

Findings

This paper describes that how flat-plate collector works for agricultural products and how to reduce the moisture content in the product (fig). Efficiency of collector was evaluated under the ambient temperatures of 24°C. Efficiency also significantly increased from 53 to 55 per cent with an increase in ambient temperature from 22 to 24 °C. Figs (Ficus carica L) were dried in the drying chamber of the flat-plate solar collector. The products were dried at temperature of 55-65°C and 15 to 20 per cent humidity.

Research limitations/implications

Because of this research chosen, the research results are beneficiary for agricultural users for drying purposes. Therefore, the researchers are encouraged to dry the agricultural product with flat-plate solar collector, because it reduced the moisture content of the product very fast.

Originality/value

This paper fulfills an identified need to study that how flat-plat solar collector can be used.

Details

World Journal of Engineering, vol. 13 no. 5
Type: Research Article
ISSN: 1708-5284

Keywords

1 – 10 of over 25000