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.