Biology subjects

Roberts, T. H.

Publications and source records attributed to Roberts, T. H..

3 recordsLinked to original sources

bioRxiv2026

Poor foam stability in gluten-free beers is associated with distinct protein composition compared with barley-malt beers

Why was the work done?: Gluten-free (GF) beers typically exhibit poorer foam stability than conventional barley malt-based beers, yet the molecular basis underlying this difference remains poorly understood. This study aimed to investigate protein-level factors associated with foam stability in GF and barley beers. How was the work done?: Three commercially produced GF beers, comprising two lagers brewed from rice or sorghum, and one pale ale brewed from a millet-buckwheat-rice blend, were compared with two commercially produced barley-malt beers, comprising a lager and a pale ale. Soluble protein was isolated from freeze-dried beer powder using TCA-acetone. Protein profiles were examined using SDS-PAGE, and proteomes were characterised and compared using label-free quantitative LC-MS/MS. What are the main findings?: GF beers showed lower soluble protein concentrations and significantly lower foam stability than the barley beers. SDS-PAGE revealed fewer and weaker protein bands in GF beers compared with barley beers. Proteomic analysis showed that barley beers were enriched in known foam-active proteins, particularly lipid transfer protein 1 (LTP1) and Protein Z (serpin family members), whereas these proteins were not detected or were detected only at very low levels in GF beers.

biochemistry↗

bioRxiv2026

Developmental stage-dependent decoupling of molecular and phenotypic responses to heat in wheat grain

Heatwaves during flowering and grain development threaten global wheat production, yet the extent to which developmental stage shapes molecular and phenotypic responses remains unclear. Here, we investigated whether heat stress (36/29{degrees}C for 48 h) imposed at closely spaced developmental stages surrounding anthesis generates stage-specific molecular responses that are associated with subsequent effects on grain properties. Heat exposure increased floret abortion most strongly when it was imposed at the trinucleate stage (TN; [~]48%) compared with the binucleate (BN) and early post-anthesis stages. Methylation levels were largely unaffected by prior heat treatments; however, heat induced stage- and locus-specific methylation changes, particularly at BN. Spatial RNA-seq revealed tissue-specific heat responses that were distinctively different in BN and TN. Integrated metabolomic analyses revealed stage-dependent metabolic reprogramming, including shifts towards stress-associated pathways. Despite heat stress at BN generating broader molecular reprogramming in developing grain, exposure at TN produced stronger effects on grain set and composition, revealing a decoupling between the magnitude of responses and phenotypic outcomes. Together, these findings demonstrate that subtle differences in developmental stage influence the complex molecular responses to heat and subsequent grain properties.

plant biology↗

bioRxiv2025

Macronutrient composition of Button Grass, Curly Mitchell Grass, Native Millet and Weeping Grass grains for their potential in modern food applications

Grains of Australian native grasses have been important components of traditional Aboriginal diets for millennia and have the potential for increased utilisation in contemporary food systems. This study assessed the macronutrient profiles of whole grains from Dactyloctenium radulans (Button Grass), Astrebla lappacea (Curly Mitchell Grass), Panicum decompositum (Native Millet), and Microlaena stipoides (Weeping Grass) compared to wheat, barley, and sorghum using proximate analysis, Osborne protein fractionation, gel electrophoresis, and carbohydrate assays. Key results were that Native Millet had high lipid content (8.0 g/100 g dry weight basis (db)), Curly Mitchell Grass had high protein (29.1 g/100 g db) and low carbohydrate content (64.0 g/100 g db), and there were substantial differences in prolamin and glutelin fractions across the species. All four native grains were gluten-free, and their starch amylose content ranged from 25.7% (Button Grass) to 41.2% (Curly Mitchell Grass), which affects starch properties. Button Grass had the highest dietary fibre content (21.9 g/100 g db), while Weeping Grass had the highest beta-glucan levels (8.6 g/100 g db), supporting functional food applications. Our findings highlight the potential for an expanded range of food applications for these grains and their contribution to human nutrition, together with implications for supporting Indigenous-led enterprises.

plant biology↗