The production of malt whisky involves the mashing of barley malt, followed by the fermentation of the resulting wort without further treatment. While this process has many parallels to the production of an all-malt beer, one of the main differentiating steps during substrate preparation is the inclusion of a boiling step for the wort in the production of beer. Other than the destructive action of the boiling process on microorganisms, the boiling also destroys all malt enzyme activity. Since a typical whisky wash is not boiled it carries through a certain proportion of microbial activity associated with the malt, but more importantly it retains some enzyme activity that has been activated during the malting and mashing processes. The changes in sugars and dextrins during both mashing and fermentation of the resulting wash were investigated. Evidence of the continuous amylolytic activity during an unboiled, all-malt wash fermentation is shown; while no ongoing amylolytic activity could be deduced during the fermentation of a boiled all-malt wort. Furthermore, the data suggests that the amylolytic activity during mashing and fermentation are different with regards to a-amylase action linked to its multiple-attack action pattern as a function of substrate conformation, temperature, and effectiveness of potential hydrolytic events.
•Synchrotron-FTIR showed the distribution of wax and PEG-isocyanate across the film.•Wax and PEG-isocyanate distributions and film surface altered the film's hydrophobicity.•High contact angle occurred when PEG-isocyanate was concentrated in the middle of the film.•Hydrophobic films possessed hierarchical wax pinnacles and textured surface.•The wax pinnacles were 10μm in diameter and distributed very closely to each other. This study proposes a novel method for improving surface hydrophobicity of glycerol plasticized high amylose (HAG) films. We used polyethylene glycol isocyanate (PEG-iso) crosslinker to link HAG and three natural waxes (beeswax, candelilla wax and carnauba wax) to produce HAG+wax+PEG-iso films. The spatial distributions of wax and PEG-iso across the thickness of these films were determined using Synchrotron-based Fourier transform infrared spectroscopy. The hydrophobicity and surface morphology of the films were determined using contact angle (CA) and scanning electron microscopic measurements, respectively. The distribution patterns of wax and the PEG-iso across the thickness of the film, and the nature of crystalline patterns formed on the surface of these films were found to be the key factors affecting surface hydrophobicity. The highest hydrophobicity (CA >90°) was created when the PEG-iso was primarily distributed in the interior of the films and a hierarchical circular pinnacle structure of solidified wax was formed on the surface.