Study of the effects of the operating conditions of a decanter centrifuge on a pilot-scale protein recovery setup from cold-pressed rapeseed press cake
(2023) KLTM01 20231Food Technology and Nutrition (M.Sc.)
- Abstract
- There is significant evidence to suggest that diets that include high levels of meat consumption have negative effects on both the environment and human health. As a result, efforts are being made to identify and characterize more plant-based proteins, such as those found in rapeseed. Rapeseed is the second-largest oilseed crop worldwide and is primarily used to produce edible oils through mechanical separation methods. During this process, a protein-rich by-product called press cake is produced, which is currently utilized as a source of protein in animal feed. Rapeseed press cake primarily consists of fibre (30%), protein (27-30%) and residual oil (20%). The use of rapeseed protein in food is limited because of its bitter taste and the... (More)
- There is significant evidence to suggest that diets that include high levels of meat consumption have negative effects on both the environment and human health. As a result, efforts are being made to identify and characterize more plant-based proteins, such as those found in rapeseed. Rapeseed is the second-largest oilseed crop worldwide and is primarily used to produce edible oils through mechanical separation methods. During this process, a protein-rich by-product called press cake is produced, which is currently utilized as a source of protein in animal feed. Rapeseed press cake primarily consists of fibre (30%), protein (27-30%) and residual oil (20%). The use of rapeseed protein in food is limited because of its bitter taste and the antinutritional components it contains. In order to effectively recover protein from rapeseed press cake, it is necessary to scale up the process beyond laboratory-scale setups. Researchers from the Department of Food Technology, Engineering and Nutrition at Lund University have successfully achieved this; consequently, the current study aimed to further enhance the process's capacity and protein recovery yield in a pilot-scale setup.
The study aimed to recover proteins from rapeseed press cake using the salt extraction method at a concentration of 0.25M and a pH of 7, followed by isoelectric precipitation at pH 3.5 and a decanter centrifuge. The optimal processing parameters for the decanter centrifuge during the first protein recovery step were an inlet feed rate of 60 L/h, 2000xg acceleration, 50 rpm differential speed, and a weir disc with an inner diameter of 68 mm. A pH of 7 was suitable for a gentler extraction of proteins, with the addition of sodium chloride resulting in an extraction coefficient of 61%. Based on thorough analysis, it was determined that the most suitable set of processing parameters for the second phase of protein recovery were an inlet flow rate of 10 L/h, 4000xg acceleration, 6 rpm differential speed, and a 56 weir disc inner diameter. The latter enhanced the overall process capability without any adverse effects on critical factors such as dry matter and protein content of the precipitate. The study found that scraping equipment surfaces resulted in a significant increase in protein recovery yield. The yield increased from 17% to 29% under the selected processing conditions. (Less) - Popular Abstract
- Studies show that eating a lot of meat can be bad for both the environment and human health. The world is getting warmer, and it's important to find ways to reduce the effects of climate change. One way to do this is to focus on producing more plant-based foods instead of meat. This is because plant-based foods create less pollution than meat does. As a result, scientists are trying to find more protein sources that come from plants, like the ones found in rapeseed. Rapeseed is a type of plant that is mostly used to make edible oil, also known as canola oil. When oil is made from rapeseed, there is a part left over that has a lot of protein in it. This part is called press cake and is mostly made up of fibre, protein, and some leftover... (More)
- Studies show that eating a lot of meat can be bad for both the environment and human health. The world is getting warmer, and it's important to find ways to reduce the effects of climate change. One way to do this is to focus on producing more plant-based foods instead of meat. This is because plant-based foods create less pollution than meat does. As a result, scientists are trying to find more protein sources that come from plants, like the ones found in rapeseed. Rapeseed is a type of plant that is mostly used to make edible oil, also known as canola oil. When oil is made from rapeseed, there is a part left over that has a lot of protein in it. This part is called press cake and is mostly made up of fibre, protein, and some leftover oil. Right now, rapeseed press cake is used as food for animals. People don't usually eat the protein from rapeseed because it can taste bitter and is hard for our bodies to use. Nevertheless, scientists from the Department of Food Technology, Engineering and Nutrition at Lund University have found a way to get the protein out of the press cake. This breakthrough opens up the possibility of incorporating this protein into food products, making it suitable for human consumption in the near future.
However, the latter has been successfully performed on a small scale, and the challenge now is not only to produce it on a larger scale but also to find the most optimal way to do it. That being said, the goal of this study was to improve the capacity of this process and get more protein from rapeseed press cake. To accomplish the former, the study was comprised of two steps, hereafter referred to as the first protein recovery step and the second protein recovery step. In the initial protein recovery process, the rapeseed press cake was milled to enable the separation of proteins from the cake in subsequent steps. The resulting powder was combined with water and mixed continuously for an hour while adjusting the pH to 7. Subsequently, the mixture was transferred to the decanter centrifuge, which is the essential machine for separating the proteins from the rapeseed press cake. This centrifuge operates continuously and separates the materials based on their density. During this step, two streams emerged from the centrifuge: a heavy phase containing residues and proteins that were unable to be separated from the rapeseed cake, and a liquid phase consisting of water and most of the proteins. That being said, different ways of operating the decanter centrifuge were tested. After conducting these experiments, it was discovered that the best way to extract protein from rapeseed press cake was to use a decanter centrifuge with an inlet flow rate of 60 L/h, 2000xg acceleration, 50 rpm differential speed, and a weir disc with a 68 mm inner diameter. These values were found to be the most optimal at this flow rate when compared to the other tested inlet flow rates, 40 and 80 L/h.
The previously obtained liquid phase is then treated with acid. This helped the proteins to settle down at the bottom by removing their electrical charge. The mixture was then separated into two parts by employing the decanter centrifuge; this time, the liquid phase is called supernatant, and the heavy phase is called precipitate. The precipitate contains most of the proteins. The same procedure was followed during the second protein recovery. Based on a thorough analysis, it was determined that the most suitable set of processing parameters for the decanter centrifuge during the second step of protein recovery were an inlet flow rate of 10 L/h, 4000xg acceleration, 6 rpm differential speed, and a 56 mm inner diameter weir disc. The latter enhanced the overall process capability without any adverse effects on critical factors such as the amount of protein obtained. It was also observed that during the second protein recovery step, a lot of precipitate was found to be stuck on the walls of the machine because of how sticky this solid material was. This solid material was important to study because it could affect how much protein could be recovered. Consequently, the study found that scraping equipment surfaces resulted in a significant increase in protein and the amount of protein recovered. To demonstrate, the protein recovery yield increased from 17% to 29% when scraping the surfaces of the equipment. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9121135
- author
- de La Cruz Padilla, Sergio LU
- supervisor
- organization
- course
- KLTM01 20231
- year
- 2023
- type
- H2 - Master's Degree (Two Years)
- subject
- keywords
- By-product, Rapeseed press cake, protein, Food engineering
- language
- English
- id
- 9121135
- date added to LUP
- 2023-06-13 10:06:48
- date last changed
- 2023-06-13 10:06:48
@misc{9121135,
abstract = {{There is significant evidence to suggest that diets that include high levels of meat consumption have negative effects on both the environment and human health. As a result, efforts are being made to identify and characterize more plant-based proteins, such as those found in rapeseed. Rapeseed is the second-largest oilseed crop worldwide and is primarily used to produce edible oils through mechanical separation methods. During this process, a protein-rich by-product called press cake is produced, which is currently utilized as a source of protein in animal feed. Rapeseed press cake primarily consists of fibre (30%), protein (27-30%) and residual oil (20%). The use of rapeseed protein in food is limited because of its bitter taste and the antinutritional components it contains. In order to effectively recover protein from rapeseed press cake, it is necessary to scale up the process beyond laboratory-scale setups. Researchers from the Department of Food Technology, Engineering and Nutrition at Lund University have successfully achieved this; consequently, the current study aimed to further enhance the process's capacity and protein recovery yield in a pilot-scale setup.
The study aimed to recover proteins from rapeseed press cake using the salt extraction method at a concentration of 0.25M and a pH of 7, followed by isoelectric precipitation at pH 3.5 and a decanter centrifuge. The optimal processing parameters for the decanter centrifuge during the first protein recovery step were an inlet feed rate of 60 L/h, 2000xg acceleration, 50 rpm differential speed, and a weir disc with an inner diameter of 68 mm. A pH of 7 was suitable for a gentler extraction of proteins, with the addition of sodium chloride resulting in an extraction coefficient of 61%. Based on thorough analysis, it was determined that the most suitable set of processing parameters for the second phase of protein recovery were an inlet flow rate of 10 L/h, 4000xg acceleration, 6 rpm differential speed, and a 56 weir disc inner diameter. The latter enhanced the overall process capability without any adverse effects on critical factors such as dry matter and protein content of the precipitate. The study found that scraping equipment surfaces resulted in a significant increase in protein recovery yield. The yield increased from 17% to 29% under the selected processing conditions.}},
author = {{de La Cruz Padilla, Sergio}},
language = {{eng}},
note = {{Student Paper}},
title = {{Study of the effects of the operating conditions of a decanter centrifuge on a pilot-scale protein recovery setup from cold-pressed rapeseed press cake}},
year = {{2023}},
}