Evaluating the Impact of Different Methods of Pre-Processing on Fermentation Capability and Physicochemical Properties of Oat Okara

Abstract

Three different processing methods of raw oat okara were used in order to determine
which method will have the highest impact in eliminating unwanted microorganisms and
making the okara acceptable for human consumption. Processed okara was also fermented
to determine the impact of processing technique on its fermenting capabilities and to
develop a starting material for a sustainable and functional food product. Okara samples
from various stages were tested for their phytic acid content, protein content, LAB count
and spore count. In the end, it was found that autoclaving produced the highest number
of LAB and had the highest protein count. All of the fermentations were successful, but
the spore count produced unreliable results. Phytic acid results showed that HPP lowered
the phytic acid levels the most, while sterilized samples had the highest levels of phytic
acid. Despite some unexpected results, the project has been deemed a success as okara
was fermented to provide a functional prebiotic starting material for foodstuffs.

Popular Abstract

Oat beverage is made by firstly mixing oats with water and then milling them together.
The liquid part that is separated becomes the final product, while the solid part is usually
discarded and not used. That solid part is oat okara. Since oat okara is made from oats
which are quite nutritious, it can be used to make a food product that has the same benefits
that oats have. Oat okara can potentially harbor various “bad” bacteria which can harm
humans, so a method to get rid of the bacteria should be used before it’s used. It can also
harbor a lot of the beneficial bacteria that are beneficial to human and gut health. For that,
the okara should be fermented. The main goals of this project was to evaluate different
methods that will make the oat okara beneficial and to ferment the oat okara into a useful
food product.
The okara underwent a process called high pressure (HPP) processing and steam
sterilization in order to eliminate the unwanted bacteria and other microorganisms. Then
it was fermented with lactic acid bacteria, which are the beneficial bacteria present in
yoghurts and fermented milk products. In total, three simultaneous fermentations were
conducted with three differently treated batches of okara. The three pre-treatment variants
were sterilized in an autoclave, processed with HPP or a combination of the two (HPP
prior to sterilization). After all of them were fermented, various methods were used in
order to determine the success of the fermentations. The beneficial bacteria were counted
to see how many of them have grown, the unwanted bacteria were counted and protein
and phytic acid content was determined.
The results showed that the beneficial bacteria grew in excellent numbers and that the
unwanted bacteria were not present in samples. The phytic acid content analysis was in-
conclusive and protein content showed a rise in proteins after fermentation. In conclusion,
the project was successful and a useful starting material for a prebiotic food product was
developed from something that is usually just thrown away. Beneficial bacteria grew on
the material, making it a functional material that could improve the human gut health.

• author: Bilic, Lovro
• supervisor: Martin Hedström
• organization: Biotechnology (MSc); Biotechnology (M.Sc.Eng.)
• course: KBTM01 20251
• year: 2025
• type: H2 - Master's Degree (Two Years)
• subject: Biology and Life Sciences
• keywords: Fermentation, oats, foodstuffs, probiotic, waste, lactic acid bacteria, phytic acid, biotechnology
• language: English
• id: 9186306
• date added to LUP: 2025-03-12 10:43:24
• date last changed: 2025-03-12 10:43:24