Rancidity Development Studies After Storage Of Oat
(2021) KBTM01 20211Biotechnology (MSc)
Biotechnology (M.Sc.Eng.)
- Abstract
- A long shelf life is of utmost importance when it comes to storage of food. Oats are expected to be easy to store like other cereals. However, oats that are stored for a long period of time are susceptible to becoming rancid, owing to its high lipid content. The lipids are mostly unsaturated fatty acids and prone to deterioration by native lipases which release fatty acids like oleic, linoleic and palmitic acids that cause a bitter flavour. Unsaturated fatty acids are also prone to oxidation, increasing the risk of deterioration and formation of unpleasant lipid oxidation products, which also contribute to the bitter flavour. As a solution, industries often use harsh heat treatments to inactivate lipases which significantly increase the... (More)
- A long shelf life is of utmost importance when it comes to storage of food. Oats are expected to be easy to store like other cereals. However, oats that are stored for a long period of time are susceptible to becoming rancid, owing to its high lipid content. The lipids are mostly unsaturated fatty acids and prone to deterioration by native lipases which release fatty acids like oleic, linoleic and palmitic acids that cause a bitter flavour. Unsaturated fatty acids are also prone to oxidation, increasing the risk of deterioration and formation of unpleasant lipid oxidation products, which also contribute to the bitter flavour. As a solution, industries often use harsh heat treatments to inactivate lipases which significantly increase the shelf-life of the oats. The treatments however may end up increasing lipid oxidation. Hence, a need for the perfect combination of heat treatment and storage condition arises to maximise the shelf life of oats.
In this study, several mild to harsh heat treatments were studied in combination with different storage conditions for 8 weeks. The heat treatments were a combination of steaming and drying, where one was steamed and dried at 70°C, another at 100°C, and the last one was steamed at 70°C and dried at 100°C. They were stored in dark at 4°C, 40°C and room temperature and in light at room temperature. It was found from the lipase assay that the heat treatments inactivated lipases effectively. The lipid profile was studied on the GC and the appearance of aldehydes was checked on the HPLC. A microbial study was also performed to check the functionality of the storage conditions as a form of quality control measure.
It was found that the heat treatments combined with the storage conditions did have an effect on the oats throughout the eight weeks. All the treated oats showed accumulation of fatty acids over time and was probably due to the combined effect of the treatments and storage conditions. The oxidation of lipids was also studied alongside using peroxide value analysis and development of aldehydes. In addition, no growth of spoilage micro organisms was found in any of the treatments throughout eight weeks. (Less) - Popular Abstract
- It is well known that oats are a popular breakfast food due to expected health benefits.
So what makes oats a health food? Surprisingly, one of the factors maybe the high fat content, with a high content of unsaturated fatty acids. The problem arises when the oats after being stored for a long time starts to taste rancid like stale fried food. This is because the unsaturated fatty acids starts to get converted into bitter tasting products. In the industries, the oats are heat treated to inactivate enzymes like lipase that would release free fatty acids which contribute to the bitter taste.
In this study, the oats were first heat treated in four different ways and then stored at different conditions of light and temperature. Gas... (More) - It is well known that oats are a popular breakfast food due to expected health benefits.
So what makes oats a health food? Surprisingly, one of the factors maybe the high fat content, with a high content of unsaturated fatty acids. The problem arises when the oats after being stored for a long time starts to taste rancid like stale fried food. This is because the unsaturated fatty acids starts to get converted into bitter tasting products. In the industries, the oats are heat treated to inactivate enzymes like lipase that would release free fatty acids which contribute to the bitter taste.
In this study, the oats were first heat treated in four different ways and then stored at different conditions of light and temperature. Gas chromatography was used to study the lipid profile. The lipid profile is like a family of fats and like all families they change and grow together with time. Over the storage period, the release of certain members like the palmitic, oleic and linoleic acid (attached to triacyglycerols) to free fatty acid form is studied. It is the released free fatty acids that makes the oat taste like old fried food. The behaviour of the members was monitored throughout the 8 weeks of storage and then compared between the treatments. It was found that the amount of free fatty acids in each oat depended on the treatment and storage condition. Oxidation of lipids form oxidation products and are also linked to rancidity. The appearance of these products were followed and compared to lipid profile using analyses such as peroxide value and HPLC. The growth of microorganisms was also looked into as a quality control measure. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9062264
- author
- Mustafa, Sharmeen LU
- supervisor
- organization
- course
- KBTM01 20211
- year
- 2021
- type
- H2 - Master's Degree (Two Years)
- subject
- keywords
- oats, rancidity, ScanOats, biotechnology
- language
- English
- additional info
- This master's thesis was carried out within the ScanOats project.
- id
- 9062264
- date added to LUP
- 2021-08-16 10:28:27
- date last changed
- 2021-08-16 10:28:27
@misc{9062264,
abstract = {{A long shelf life is of utmost importance when it comes to storage of food. Oats are expected to be easy to store like other cereals. However, oats that are stored for a long period of time are susceptible to becoming rancid, owing to its high lipid content. The lipids are mostly unsaturated fatty acids and prone to deterioration by native lipases which release fatty acids like oleic, linoleic and palmitic acids that cause a bitter flavour. Unsaturated fatty acids are also prone to oxidation, increasing the risk of deterioration and formation of unpleasant lipid oxidation products, which also contribute to the bitter flavour. As a solution, industries often use harsh heat treatments to inactivate lipases which significantly increase the shelf-life of the oats. The treatments however may end up increasing lipid oxidation. Hence, a need for the perfect combination of heat treatment and storage condition arises to maximise the shelf life of oats.
In this study, several mild to harsh heat treatments were studied in combination with different storage conditions for 8 weeks. The heat treatments were a combination of steaming and drying, where one was steamed and dried at 70°C, another at 100°C, and the last one was steamed at 70°C and dried at 100°C. They were stored in dark at 4°C, 40°C and room temperature and in light at room temperature. It was found from the lipase assay that the heat treatments inactivated lipases effectively. The lipid profile was studied on the GC and the appearance of aldehydes was checked on the HPLC. A microbial study was also performed to check the functionality of the storage conditions as a form of quality control measure.
It was found that the heat treatments combined with the storage conditions did have an effect on the oats throughout the eight weeks. All the treated oats showed accumulation of fatty acids over time and was probably due to the combined effect of the treatments and storage conditions. The oxidation of lipids was also studied alongside using peroxide value analysis and development of aldehydes. In addition, no growth of spoilage micro organisms was found in any of the treatments throughout eight weeks.}},
author = {{Mustafa, Sharmeen}},
language = {{eng}},
note = {{Student Paper}},
title = {{Rancidity Development Studies After Storage Of Oat}},
year = {{2021}},
}