A preliminary study about the influence of high hydrostatic pressure processing on the physicochemical and sensorial properties of a cloudy wheat beer

Abstract

High hydrostatic pressure (HHP) (400 MPa/15 min, 500 MPa/10 min, 600 MPa/5 min at 20°C) and heat (60°C/15 min) processing of wheat beers were evaluated by examining their impacts on microorganisms, colloidal haze, flavour, foam stability and shelflife prediction during 84 days of storage at 20°C. The results obtained showed that the microbiological stability of HHP beers was comparable with heat-treated samples, and the development of both aerobic bacteria and lactic acid bacteria was inhibited for 84 days of storage. The main parameters of the wheat beer, such as ethanol content, original extract, pH, bitterness and viscosity, were scarcely affected by either treatment compared with the control samples; however, heat pasteurization increased the colour value. Heat-pasteurized beer resulted in an increase in the phenethyl alcohol concentration and a decrease in isoamyl acetate and ethyl acetate levels compared with the HHP samples. These treatments did not affect the amount of 4-vinylguaiacol and 4vinylphenol in the beer. The HHP-treated beers had higher colloidal haze and foam stability values than the heat-pasteurized beers. Dynamic light scattering analysis showed that HHP treatments at 500 MPa/10 min resulted in smaller and more uniform particle sizes, which had a positive effect on beer haze stability during storage.

Investigation of total polyphenol, antioxidant activity, and levels of metals in Ethiopian commercial beers

“…This difference is due to variation in the type and amount of hope added in the brewing process. The physicochemical properties Ethiopian commercial beers that was studied here are in agreement with other reports [13,17,18].…”

A preliminary study of the quality attributes of a cloudy wheat beer treated by flash pasteurization

“…Lactic acid bacteria counts were made using de Man Rogosa Sharpe agar containing 10 mg/L of cycloheximide (Sigma‐Aldrich Co., USA). All of the media used and methods of preparation have been described elsewhere . All plates were incubated at 26°C for up to 14 days.…”

Reduced acetaldehyde production by genome shuffling of an industrial brewing yeast strain

“…The flame ionization detector temperature was 250°C. Helium was used as the carrier gas at 15 psi . The determination of acetaldehyde and diacetyl of beers was performed using a gas chromatograph (Clarus 500, GC system, Perkin Elmer, USA) coupled with a headspace sampler (HS 40, Perkin Elmer, USA) with an electron capture detector .…”