Influência da alta pressão hidrostática na sacarificação do mosto cervejeiro

Abstract

Beer is the most consumed beverage in the world and Brazil is the third biggest producer just behind USA and China. It is an alcoholic beverage made from malted cereals, water, hops and yeast. To produce beer, water and malt are mixed and heated, what it is called the mashing step which aims to promote gelatinization and the starch hydrolyzation by the enzymes of the malt: α and β amylases. Since by using high hydrostatic pressure (HHP) it is possible to realize both processes (gelatinization and hydrolysis), mashing can use this technology without the need of heating and to raise productivity of the brewhouse. The aim of this study was to evaluate the use of HHP on starch hydrolysis and the sugar profile formed. For this, worts (water and malt solution – ratio 4:1) were treated with HHP in 300, 400 or 500 MPa for 5, 10 and 15 minutes, and as control sample, the same solution was treated with heat (1st step: 52°C / 20 min; 2nd step: 72 °C / 25 min; 3rd step: 78 °C / 5 min). After, it was made the sugar profile by high performance liquid chromatography (HPLC), soluble solids content by density and microscopic analysis of gelatinized starch. As results, it was possible to verify a decrease on starch concentration (indication of hydrolysis) and a progressive swelling (indication of gelatinization) of the granules, especially at 500 MPa. The iodine test, which assesses starch presence, showed the same results of microscopy analysis and, on both qualitative assessments, the pressure level was of great influence and only on the iodine test, time seems to have had any influence since it was observed a decrease on starch content as time increased at 500 MPa. The sugar profile revealed five main sugars in all worts: glucose, sucrose, fructose, maltose and maltotriose. The maltose, maltotriose and fructose’s contents of the pressurized worts were similar to the heat treatment (500 MPa / 5 – 15 min). Fructose and glucose exhibited and increase in most of the pressurizations. Sucrose and soluble solids contents of the pressurized samples were lower than the heated one. Among the pressure levels studied, there was a trend of increase on soluble solids, maltose, maltotriose and glucose’s content as the pressure was raised and generally, pressure influenced all sugar’s contents, except from sucrose. Time had a small effect on sugar’s content in some pressure levels. The variations observed to maltose, maltotriose and soluble solids were adjusted to mathematical models of fourth grade that exhibited a strong influence of pressure without dependence of the time effect. Additionally, the principal component analysis explained the variance with formation of three main clusters: heated wort, 500 MPa / 10 or 15 min wort and the other pressurized worts. The results showed that high hydrostatic pressure was able to promote desirable changes on mashing concerning gelatinization and hydrolysis with formation of desirable sugars, especially at 500 MPa. It suggests that it’s possible to produce wort by HHP providing productivity gains, once HHP takes less time (5 min against 80 min of usual heat process) and less energy consumption.