Academia.edu no longer supports Internet Explorer.
To browse Academia.edu and the wider internet faster and more securely, please take a few seconds to upgrade your browser.
Food Wastage has always been an issue since the beginning of mankind. . It will be a great saving of the food if this wastage is stopped by using efficient preservation techniques and make the food available in the period of scarcity and reduce the volumes of food that we waste every year. We are living in a remarkable age, the age of advancement and emerging technologies. The researchers, engineers and technologists are developing new techniques and appliances to tackle all such problems. We have preservation methods like dehydration, canning, heating, refrigeration and freezing, drying and treating with chemicals/acids and salts. Amongst these technologies, is the newly developed technology called Freeze Drying or Lyophilization, which is very useful and has been refined over years. Talking about our own country, although freeze dryers or lyophilizers are in use in some industries and research labs of a few institutes and pharmaceuticals, but it is still not very common. In Pakistan other than major agricultural crops, a large variety of Fruits and Vegetables, meat and poultry products are produced in abundance. A major chunk of these go to waste each year due to one reason or the other. So here freeze drying can play a vital role in saving the foods, increasing the shelf-life and consuming it in the periods of scarcity. Freeze dried products can even be exported to earn foreign exchange (e.g. Pakistani Mangoes and Citrus to countries where they are not grown). This research synopsis aims to reflect on establishment of parameters and process steps to fabricate a cost-effective home freeze dryer and indigenize it among the people of Pakistan.
American Journal of Engineering Research (AJER)
Fabrication of a Freeze Dryer Using Locally Sourced Material2023 •
This study presents the design and construction of a freeze dryer system within a 330.2mm x 508mm x 457.2mm rectangular chamber, crafted from a 4mm galvanized metal sheet at the University of Ibadan, Nigeria. The chamber featured a dual-layer configuration with an inner and outer layer fortified by a 1.7mm x 1.7mm square gauge hollow pipe made of mild steel. This reinforcement aimed to prevent implosion, particularly during the dehydration phase of the freeze-dryer process.The system's design was used based on the specific heat capacity of relevant fruits and vegetables, including Pears, Tomatoes, and Carrots, each characterized by heat capacity values of 3.62KJ/kg o C, 3.98KJ/kg o C, and 3.79KJ/kg o C, respectively. For the preservation of nutritional qualities during drying and subsequent reconstitution, products were initially frozen and then subjected to sublimation.Monitoring of key parameters within the chamber, such as dry-bulb and dew point temperatures, and relative humidity, was facilitated by a USB data recorder. While the chamber effectively achieved dry-bulb temperatures ranging from an initial 28°C to 1°C post-drying, and dew point temperatures from 20.8°C initially to-6.1°C post-drying, these temperatures remained below the target threshold of 5°C for optimal drying. This discrepancy may be attributed to potential leakages along welded portions of the chamber, impeding the product's transition to the desired dry state.Consequently, the final moisture content essential for safe storage of the dried product was not attained due to these challenges. Comparative analysis revealed lower temperatures (dry-bulb and dew point) and relative humidity in the freeze-dried product compared to imported counterparts. This discrepancy may be linked to the welding method employed in constructing the chamber, allowing air exchange between the chamber's interior and its surroundings.The freeze-drying process extended for 6 hours, resulting in a 1/10 reduction in the product's size when weighed.
International Journal of Engineering Science Invention (IJESI)
Design, Construction and Testing Of a Freeze Dryer for Vegetables2019 •
Drying of vegetables by farmers in Benue State Nigeria has not been very successful due to unavailability of appropriate drying technologies such as a freeze dryer. Farmers no longer produce in large quantity due to fear of wastage which also results to labour lost. The main purpose of this study was to evolve a better way of drying vegetables for longer shelf live. The study designed, constructed and evaluated the performance of the freeze dryer. Digital thermometer, vacuum gauge and stopwatch were used to determine the freezing temperature, freeze drying vacuum pressure and freeze drying time. Tomato, pepper and okra were tested on the freeze dryer and were freeze dried at a temperature of-2℃,-1.5℃ and-1.4℃ and vacuum pressure of-29inHg,-24inHg and-22inHg, the freeze drying time was 20hours, 10hours and 10hours respectively. 0% moisture content was achieved with the aid of the vacuum as moisture does not exist in a vacuum space. The freeze dried products were able to regain their freshness when reconstituted with water. It has been recommended among others that farmers should be encouraged to use freeze dryer for drying tomato, pepper and okra.
In the production of artificially dried food products to be used in dishes, soups and breakfast cereals, mainly two technologies are dominating the industrial production today. These technologies are direct heated driers operated at 60 o C to 90 o C and vacuum freeze drying operated below -30 o C. Direct heated dryers have lower production costs than vacuum freeze dryers but with a much lower quality of the dried product. On the other hand, the vacuum freeze drying equipment high cost limits its use. This paper presents atmospheric freeze drying with heat pumps as a new alternative for producing dried food products with high quality, which is similar as in vacuum freeze drying but with considerable lower production costs. The focus in the paper is on design, dimensioning and operation of atmospheric freeze dryers with heat pumps using combined drying mode with temperatures below and above the product freezing point.
2020 •
Freeze-drying, also known as lyophilization, is a process in which water in the form of ice under low pressure is removed from a material by sublimation. This process has found many applications for the production of high quality food and pharmaceuticals. The main steps of the freeze-drying process, such as the freezing of the product and primary and secondary drying, are described in this paper. The problems and mechanisms of each step of the freeze-drying process are also analyzed. The methods necessary for the selection of the primary and secondary end processes are characterized. The review contains a description of the effects of process conditions and the selected physical properties of freeze-dried materials, such as structural properties (shrinkage and density porosity), color, and texture. The study shows that little attention is given to the mechanical properties and texture of freeze-dried materials obtained from different conditions of the lyophilization process.
International Journal of Food Science and Technology
Analysis of operating strategies in the production of special foods in vials by freeze drying1997 •
Aaps Pharmscitech
Investigation of Design Space for Freeze-Drying: Use of Modeling for Primary Drying Segment of a Freeze-Drying CycleIn this work, we explore the idea of using mathematical models to build design space for the primary drying portion of freeze-drying process. We start by defining design space for freeze-drying, followed by defining critical quality attributes and critical process parameters. Then using mathematical model, we build an insilico design space. Input parameters to the model (heat transfer coefficient and mass transfer resistance) were obtained from separate experimental runs. Two lyophilization runs are conducted to verify the model predictions. This confirmation of the model predictions with experimental results added to the confidence in the insilico design space. This simple step-by-step approach allowed us to minimize the number of experimental runs (preliminary runs to calculate heat transfer coefficient and mass transfer resistance plus two additional experimental runs to verify model predictions) required to define the design space. The established design space can then be used to understand the influence of critical process parameters on the critical quality attributes for all future cycles.
European Journal of Pharmaceutics and Biopharmaceutics
On the use of a micro freeze-dryer for the investigation of the primary drying stage of a freeze-drying process2019 •
2020 •
Global Research Journal of Business Management
AN APPRAISAL OF RATIO ANALYSIS ON INVESTMENT DECISION MAKING IN COMMERCIAL BANKS IN NIGERIA2021 •
Hellenistic Warfare V. (conference in Barcelona)
Euthydemus wages war Darband Wall in the Bactro-Sogdian borderlands reconsidered2022 •
Contra la tirania tipologizante en la arqueologia
Palenques y empalizadas. Una revisión del problema de la complejidad durante el periodo de contacto en el oriente de VenezuelaEcological Entomology
Local and regional climate variables driving spring phenology of tortricid pests: a 36 year study2018 •
Annals of Surgery
Marking Axillary Lymph Nodes With Radioactive Iodine Seeds for Axillary Staging After Neoadjuvant Systemic Treatment in Breast Cancer Patients2015 •
2024 •
2021 •
Frontiers in Neurology
Diet in Parkinson's Disease: Critical Role for the Microbiome2019 •
Journal of The Medical Library Association
Development and validation of a modified LibQUAL scale in health sciences libraries: application of Structural Equation Modeling2023 •
European Journal of Cancer
Determination of urinary 8-hydroxydeoxyguanosine by automated coupled-column high performance liquid chromatography: a powerful technique for assaying in vivo oxidative DNA damage in cancer patients1995 •
Journal of Agriculture and Ecology Research International
Effects of Tin Mine Tailings on the Growth and Development of Common Bean (Phaseolus vulgaris L.) in Jos, Nigeria2019 •