Investigation of Fermentation as a Processing Technique for HPP-treated Oat Okara and Its Potential Application in Food products
(2025) KLTM06 20251Food Technology and Nutrition (M.Sc.)
- Abstract
- Introduction: Side-stream residue, oat okara, from the oat-milk production contains valuable nutrients but possesses a high risk of microbial spoilage. Valorisation of oat okara is therefore important to make sure that the oat beverage production stays sustainable. In this project, High-pressure processing (HPP), heat treatment and Lactobacillus fermentation have been evaluated for their microbial and nutritional changes of the oat okara.
Method: Four different pre-treatments were performed: HPP using 200+600 MPa and 600 MPa, one heat treatment utilizing 80°C for 30 minutes and one using pressure at 200 MPa followed by heat treatment. All pre-treated oat okara samples were then enzymatically hydrolysed and fermented using Lactobacillus... (More) - Introduction: Side-stream residue, oat okara, from the oat-milk production contains valuable nutrients but possesses a high risk of microbial spoilage. Valorisation of oat okara is therefore important to make sure that the oat beverage production stays sustainable. In this project, High-pressure processing (HPP), heat treatment and Lactobacillus fermentation have been evaluated for their microbial and nutritional changes of the oat okara.
Method: Four different pre-treatments were performed: HPP using 200+600 MPa and 600 MPa, one heat treatment utilizing 80°C for 30 minutes and one using pressure at 200 MPa followed by heat treatment. All pre-treated oat okara samples were then enzymatically hydrolysed and fermented using Lactobacillus plantarum 299v. Microbial analysis were conducted on the samples between all processing steps and after storage for 2-3 weeks. The pH, Lactobacillus count and their survivability after three weeks, and phytic acid were analysed. The fermented oat okara was also centrifuged and implemented in a vegetarian patty with 20% and 40% oat okara respectively.
Results and Discussion: Bacillus species decreased after HPP and heat treatment, but the total aerobic count, and the yeast and mould load were somewhat increased after pressure treatment. Unexpectedly the Bacillus count increased after Lactobacillus fermentation. Shelf life for non-fermented samples seemed to be around 1 week due to the growth of yeast and mould for all samples except for the heat-treated sample. The fermentation decreased the pH from around 6.3 to 4.0 and the Lactobacillus load increased from approximately log 8.5 CFU/g to 9.0 CFU/g for all samples. The viability of the Lactobacillus load was contained during a three-week period. The protein content in the oat okara was significantly increased for all fermented and centrifuged samples compared to crude oat okara. The phytic acid content could not be quantified but the detection methodology showed potential for future analysis. A tasty vegetarian patty was made that had a final protein content of 13% (20% oat okara) and 14% (40% oat okara) respectively. (Less) - Popular Abstract
- Oat beverage’s hidden byproduct: Can oat okara become the food of the future?
Are you one of those people who use oat beverage in your coffee every day? Or perhaps one of those who insists oat beverage never can replace milk? Either way, have you ever thought about what happens to the leftover pulp? For every litre of oat beverage produced, approximately 0.2-0.4 kg of byproduct, called oat okara, is generated. While often being discarded or used as animal feed, the fibre-rich residue has a high nutritional value. However, the challenge of keeping the oat okara away from spoilage due to a high microbial load remains. Therefore, this project aims to, through fermentation and prior heat- and high-pressure processing (HPP) treatments, turn... (More) - Oat beverage’s hidden byproduct: Can oat okara become the food of the future?
Are you one of those people who use oat beverage in your coffee every day? Or perhaps one of those who insists oat beverage never can replace milk? Either way, have you ever thought about what happens to the leftover pulp? For every litre of oat beverage produced, approximately 0.2-0.4 kg of byproduct, called oat okara, is generated. While often being discarded or used as animal feed, the fibre-rich residue has a high nutritional value. However, the challenge of keeping the oat okara away from spoilage due to a high microbial load remains. Therefore, this project aims to, through fermentation and prior heat- and high-pressure processing (HPP) treatments, turn oat okara into a safe, nutritional and tasty food ingredient.
One type of bacterium that is specifically threatening for oat products is the ones belonging to the genus Bacillus, which often are spore-forming and can produce toxins. Spores and toxins from certain species of Bacillus are resistant to conventional pasteurizations techniques and new approaches are needed to reduce them in different food products. In this report, an indication of a decrease of this genus was found for the products being HPP-treated but increased after fermentation. Despite that the fermentation increased the Bacillus genus, other positive effects from the fermentation were observed. Namely, after utilizing the starter culture Lactobacillus plantarum 299v for fermenting the oat okara, a reduction of pH and an increase of the starter culture could be obtained. Furthermore, the fermentation in combination with a centrifugation step also made the final product higher in protein content and gave a pleasant taste when incorporated in a vegetarian patty.
These results contribute to the first insight into how oat okara can be processed for improving the safety, nutrient and sensorial characteristics. It also demonstrates challenges with sampling and analysing microbial and nutritional properties of food matrixes paving the way for future improvements of the food research. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9202972
- author
- Erlinge, Emma LU and Johansson, Maja LU
- supervisor
- organization
- course
- KLTM06 20251
- year
- 2025
- type
- H2 - Master's Degree (Two Years)
- subject
- keywords
- oat okara, food side-streams, lactic acid fermentation, high-pressure processing (HPP), bacillus cereus, vegetarian patty, shelf life, oat okara protein, phytic acid, food engineering nutrition and food chemistry
- language
- English
- additional info
- Uppdaterad omslagsbild på uppsats / updated cover of thesis 2025-07-03
- id
- 9202972
- date added to LUP
- 2025-06-19 14:36:09
- date last changed
- 2025-07-03 14:38:34
@misc{9202972,
abstract = {{Introduction: Side-stream residue, oat okara, from the oat-milk production contains valuable nutrients but possesses a high risk of microbial spoilage. Valorisation of oat okara is therefore important to make sure that the oat beverage production stays sustainable. In this project, High-pressure processing (HPP), heat treatment and Lactobacillus fermentation have been evaluated for their microbial and nutritional changes of the oat okara.
Method: Four different pre-treatments were performed: HPP using 200+600 MPa and 600 MPa, one heat treatment utilizing 80°C for 30 minutes and one using pressure at 200 MPa followed by heat treatment. All pre-treated oat okara samples were then enzymatically hydrolysed and fermented using Lactobacillus plantarum 299v. Microbial analysis were conducted on the samples between all processing steps and after storage for 2-3 weeks. The pH, Lactobacillus count and their survivability after three weeks, and phytic acid were analysed. The fermented oat okara was also centrifuged and implemented in a vegetarian patty with 20% and 40% oat okara respectively.
Results and Discussion: Bacillus species decreased after HPP and heat treatment, but the total aerobic count, and the yeast and mould load were somewhat increased after pressure treatment. Unexpectedly the Bacillus count increased after Lactobacillus fermentation. Shelf life for non-fermented samples seemed to be around 1 week due to the growth of yeast and mould for all samples except for the heat-treated sample. The fermentation decreased the pH from around 6.3 to 4.0 and the Lactobacillus load increased from approximately log 8.5 CFU/g to 9.0 CFU/g for all samples. The viability of the Lactobacillus load was contained during a three-week period. The protein content in the oat okara was significantly increased for all fermented and centrifuged samples compared to crude oat okara. The phytic acid content could not be quantified but the detection methodology showed potential for future analysis. A tasty vegetarian patty was made that had a final protein content of 13% (20% oat okara) and 14% (40% oat okara) respectively.}},
author = {{Erlinge, Emma and Johansson, Maja}},
language = {{eng}},
note = {{Student Paper}},
title = {{Investigation of Fermentation as a Processing Technique for HPP-treated Oat Okara and Its Potential Application in Food products}},
year = {{2025}},
}