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The soil selenium (Se) content and bioavailability are important for human health. In this regard, knowing the factors driving the concentration of total Se and bioavailable Se in soils is essential to map Se, enhance foodstuffs' Se content, and improve the Se nutritional status of humans. In this study, total Se and Se bioavailability (i.e., phosphate extracted Se) in surface soils (0–20 cm) developed on different strata were analyzed in a Se-enriched region of Southwest China. Furthermore, the interaction between the stratum and soil properties was assessed and how did the stratum effect on the concentration and spatial distribution of Se bioavailability in soils was investigated. Results showed that the median concentration of total Se in soils was 0.308 mg/kg, which is higher than China's soil background. The mean proportion of phosphate extracted Se in total Se was 12.2 %. The values of total Se, phosphate extracted Se, and soil organic matter (SOM) in soils increased with the increasing stratum age. In contrast, the coefficient of weathering and eluviation (BA) values decreased. The analysis of statistics and Geodetector revealed that the SOM, stratum, and BA were the dominant controlling factors for the contents and distributions of soil total Se and phosphate extracted Se. This study provided strong evidence that the soil properties that affected the total Se and Se bioavailability were modulated by the local geological background, and had important practical implications for addressing Se malnutrition and developing the Se-rich resource in the study region and similar geological settings in different parts of the globe. [Display omitted] • The soil Se total concentrations were higher than the soil background in China. • SOM has a significant positive relationship with Se total and Se phosphate. • Stratum∩SOM exceeds all other interaction effects for Se phosphate. • Stratum provides the source of Se in soils and modulates the SOM and BA. [ABSTRACT FROM AUTHOR]

Pectin is a common food additive used for enhancing the health benefits of dietary fibers, and is the most structurally and functionally complex polysaccharide, rich in galacturonic acid. In this study, we investigated changes in the aggregative property of gluten, their rheological properties, and secondary structure, as well as in the gluten network, when supplemented by apple pectin. Adding pectin was shown to enhance the macromolecular aggregation of gluten, and improved the rheological properties of dough by inducing a dense network of gluten. The presence of pectin decreased α-helix content but increased β-sheet and β-turn structure of gluten, suggesting that pectin affected the hydration level of gluten, leading to the formation of aggregated β-structures. This study provides a better understanding of pectin functionality in wheat flour dough, and is valuable for guiding in the application of pectin in wheat flour food products. [Display omitted] [ABSTRACT FROM AUTHOR]