Effects of Microwave and Enzyme Treatments on the Softness of Barley Kernels

Abstract

The present master thesis was performed in cooperation with the company “Aventure AB”. The company’s R&D department envisioned a new yoghurt-based product able to decrease the blood glucose levels after a meal. The innovative characteristic of the product is due to the diet fibers of the barley grain, which is going to be incorporated inside the yoghurt.
The preliminary experiments which were carried by the Aventure R & D team were very promising as they revealed that the decrease of the blood glucose levels could last up to 10 to 12 hours from the consumption of the product. The most important problem with barley, is that its kernels are very hard and thus, if not softened, they cannot be used in food formulation.
The aim of this present study was to determine if microwave or enzymatic treatments (xylanase, cellulase) could have any effect on the barley kernel’s hardness. The results were promising where microwave heating was related. Unfortunately, the present study is unable to claim the same about the enzymatic treatment.
The better results were obtained by soaking the barley kernels for 2 minutes in distilled water and then treating them with microwave radiation for 1 minute followed by 4 hours of drying in the convection oven (2m/s velocity of air and 50oC air temperature). Acceptable results were also obtained after 8 hours of drying. The hardness of the kernels was evaluated using the texture analyzer in Lund University. Additionally, microwave treatment resulted in a very pleasant roasted taste, after tasting them, which is desirable in food products.

Popular Abstract

The present study was conducted in Lund University in cooperation with Aventure AB company in Sweden. Nowadays consumers in Sweden and all over the word are becoming more and more health conscious and asking healthier and more functional food products; food industries are developing such products to meet the demands of the consumers.
The scope of this study was to find ways to improve the texture of barley kernels in order to use them for the development of a granola1 as a supplement to a new type of yoghurt aiming to lower the blood glucose levels after each meal. Barley is an excellent ingredient for granola products as it contains large amounts of dietary fibers as discussed in this study. The initial problem though, was that the barley kernels were so hard that it was impossible to chew and thus they were of no use in a formulation. During the experiments, which lasted about 6 months, we tried to improve the texture without losing the botanical characteristics of the barley kernels which make them so important. Several treatments using microwave radiation and enzymes were used and then the texture was evaluated with the texture analyzer in the laboratory of Lund University.
Both microwave and enzyme treatments gave very good results in improving the texture of the barley kernels, but the enzyme treatment gave an unpleasant taste to the barley. The treatment is also very expensive, so it was not possible to use it on an industrial scale. On the other hand, as mentioned in the discussion and conclusion parts of this thesis, microwave treatments gave excellent results in improving the texture of the kernels without leaving an unpleasant taste. Finally microwave treatment was the cheapest of the treatments and gave the best results.
In the last part of the thesis, some more ways on how to improve the present experiments in future works are presented in brief.

• author: Nikolakakis, Ilias
• supervisor: Yvonne Granfeldt
• organization: Food Technology and Nutrition (M.Sc.)
• course: KLTM01 20191
• year: 2020
• type: H2 - Master's Degree (Two Years)
• subject: Agriculture and Food Sciences; Technology and Engineering
• keywords: food engineering, livsmedelsteknik
• language: English
• id: 9005958
• date added to LUP: 2020-03-26 08:56:48
• date last changed: 2020-03-26 08:56:48