Overall Antioxidant Properties of Malt and How They Are Influenced by the Individual Constituents of Barley and the Malting Process

Abstract

In the past several years researchers have focused on the study of the antioxidant properties of barley and barley malt as well as their influence on beer quality. Some malt constituents have been reported as potent antioxidants due to their radical-scavenging and reducing properties, with a positive effect on beer oxidative stability. However, barley and malt can suffer some serious modifications during malting and roasting, namely on the levels of phenolic compounds and the development of Maillard reaction products, which may have a great impact on the overall antioxidant properties of malt. Although some studies have reported an increase of the antioxidant capacity during malting, others have mentioned an opposite effect. Recently, researchers have shown that compounds developed in malt during heat treatment at high temperature and long periods of time, as result of the Maillard reaction, can also exhibit pro-oxidant properties involving the metal-catalyzed Fenton reaction due to its reductive properties. This paper reviews important information and recent data regarding the chemical changes malting and roasting undergo along with their influence on the different antiand pro-oxidant properties described for barley and malt. The contribution of individual components to the overall antioxidant capacity of malt is also discussed.

The Impact of Simple Phenolic Compounds on Beer Aroma and Flavor

“…This achieved 42-70 µg/g, or 4.9-8.3 ppm ferulic acid in the wort [11]. These numbers are in general agreement with similar studies that used different sets of barley malts [9,14,[18][19][20], however wide ranges can be found within the published literature [21]. This observed variability is most commonly linked to alternative extraction methods between researchers.…”

Evaluation of total phenolic content and antioxidant activity of malting and hulless barley grain and malt extracts

“…Malting is a complex process responsible for modifications in the composition of barley. These structural changes involve many enzyme degradations, including enzymatic release of phenolic compounds bound to cellular structures of barley and with glycosylation reactions during malting, leading to easier extraction of free phenolic acids due to changes in the matrix in the early kilning (Carvalho et al 2016). Leitao et al (2012) found in their study that malting allowed a better release and/or extraction of phenolic compounds, while the first brewing step caused the most significant decrease in the total polyphenols extracted.…”

“…Among cereal grains, barley is naturally high in phenolic compounds. The majority of the barley phenolic compounds have also been identified in malt, which implies that natural antioxidants present in barley make a large contribution to the antioxidant activity of malt (Carvalho et al 2016). Therefore, the screening of different barley varieties for their antioxidant potential seems important from the aspect of malt and beer production.…”

Technological influence on sensory stability and antioxidant activity of beers measured by ORAC and FRAP

“…Both brewing raw materials are rich in antioxidants. Barley ( Hordeum vulgare L.) contains a variety of phenolic compounds: Benzoic and cinnamic acid derivatives, hordatines, lignans and flavonoids . During malting, the phenolic content of grain extracts increases due to the enzymatic release of phenolic acids from cell‐wall polysaccharides and due to the enhanced extractability of the malted grain .…”