Genotypic, Environmental, and Processing Effects on Phenolic Content and Antioxidant Activity in Barley and Wheat

Phenolic compounds are increasingly valued for their contribution to the antioxidant capacity and nutritional characteristics of cereals. In this study, 38 barley and wheat varieties grown in Croatia were evaluated over three consecutive years to assess the effects of cereal type, growing season, and malting on total phenolic content (TPC) and antioxidant activity (AOA). Wheat and barley are essential small grains because of their importance in human and animal nutrition and their wide adaptability. Barley showed significantly higher TPC (1.37 mg Gallic Acid Equivalent (GAE)/g dw) and AOA (63.34%) compared to wheat varieties (TPC 0.85 mg GAE/g dw; AOA 20.09%), with hull-less barley having the highest values (TPC 1.48 mg GAE/g dw; AOA 66.76%). The growing year significantly affected the accumulation of phenolic compounds, with 2019 yielding the highest TPC (1.46 mg GAE/g dw) and AOA (59.85%). Malting enhanced TPC and AOA, particularly in spring barley, with the most pronounced increase recorded in 2017. Statistical analyses demonstrated clear grouping of samples based on growing year and malting status, with hull-less barley varieties forming stable clusters. Hull-less barley varieties such as GZ-192 have emerged as a valuable source of natural antioxidants with potential application in health-promoting food products.