Effects of Growth Conditions and Cultivar on the Content and Physiochemical Properties of Arabinoxylan in Barley.

The present study aims to evaluate the effect of the growth conditions and the cultivar on the total and water-extractable (W-E) arabinoxylan (AX) in barley. For this purpose, nine barley varieties from two different years were analyzed. The total AX content ranged from 5.97 to 8.98 wt % d.m., while the W-E AX ranged from 0.06 to 0.35 wt % d.m. The W-E AX molecular properties were characterized by high-pressure size exclusion chromatography (HPSEC)-triple detector array (TDA). The molecular weight was between 2.3 × 105 and 12.6 × 105 Da, the polydispersity was between moderate and broad (1.1 < Mw/Mn < 4.3), and the conformation was a stiff semiflexible coil (0.5 < α < 1.3). The results indicate that the year influences the content of total AX and W-E AX and some molecular characteristics of W-E AX, such as its polydispersity and its conformation. Finally, the results demonstrated that the W-E AX can be used as an index of the malting attitude of barley because it positively correlates with germinative energy and kernel dimension.

Effect of Growth Conditions and Genotype on Barley Yield and ß-Glucan Content of Kernels and Malt.

This study was conducted to evaluate the effect of growth conditions and genotype on the barley yield and ß-glucan content of grain and malt. Total and water-extractable (W-E) ß-glucans and their molecular and structural properties were analyzed in nine 2-row barley varieties and corresponding malts. The total ß-glucan content of barley is not influenced by year or by the cultivar, while the grain yield and W-E ß-glucan content are significantly influenced by the year. Barley W-E ß-glucans have a molecular weight between 1.0 × 105 and 4.0 × 105 Da and a random coil conformation. ß-Glucan levels in malt are significantly lower than in barley, and neither the total nor the W-E ß-glucans are influenced by environmental factors or genetic aspects. W-E ß-glucans are mainly composed of fractions with Mw values below 1.0 × 105 Da. In conclusion, the molecular characterization of ß-glucans could represent a powerful tool to understand their role in the brewing process.

Changes in the Fusarium Head Blight Complex of Malting Barley in a Three-Year Field Experiment in Italy.

In this study, conducted for three years on eleven malting barley varieties cultivated in central Italy, the incidence of different mycotoxigenic fungal genera, the identification of the Fusarium species associated with the Fusarium Head Blight (FHB) complex, and kernels contamination with deoxynivalenol (DON) and T-2 mycotoxins were determined. The influence of climatic conditions on Fusarium infections and FHB complex composition was also investigated. Fusarium species were always present in the three years and the high average and maximum temperatures during anthesis mainly favored their occurrence. The FHB complex was subject to changes during the three years and the main causal agents were F. poae, F. avenaceum, F. tricinctum and F. graminearum, which, even if constantly present, never represented the principal FHB agent. The relative incidence of Fusarium species changed because of climatic conditions occurring during the seasons. The FHB complex was composed of many different Fusarium species and some of them were associated with a specific variety and/or with specific weather parameters, indicating that the interaction between a certain plant genotype and climatic conditions may influence the presence of Fusarium spp. causing infections. With regard to mycotoxin contamination, T-2 toxin, in some cases, was found in kernels at levels that exceeded EU recommended values.