Morphological and biochemical properties of Australian native grains

Abstract

There is growing interest in Australian native grains for their potential to contribute to health-focused food innovation, ecological resilience, and the revitalisation of First Nations food systems. This thesis investigates the morphological, biochemical, and functional characteristics of four native grasses—Panicum decompositum (Native Millet), Dactyloctenium radulans (Button Grass), Microlaena stipoides (Weeping Grass), and Astrebla lappacea (Curly Mitchell Grass)—to assess their potential for use alongside domesticated cereals. In addition to addressing sustainability, this research may help support future opportunities for Indigenous communities through the renewed recognition and use of traditional grain species. The selected native grains were compared with wheat, barley, and sorghum as reference crops. Stereo and fluorescence microscopy were used to examine grain shape, embryo structure, and the distribution of protein and cell wall components. Among the findings, proximate analysis revealed that certain native grains had protein and lipid contents comparable to, or exceeding, those of domesticated cereals. Carbohydrate profiling included total starch, amylose, resistant starch, dietary fibre, and β-glucan. Certain native species displayed notably high β-glucan and amylose levels, which are linked to improved glycaemic response, digestive health, and enhanced texture and structural integrity in gluten-free products. All four species were confirmed to be gluten-free. The functional behaviour of the grains during processing was assessed to determine their potential roles in food formulation, with a focus on texture, absorption, and aeration characteristics. Protein composition was evaluated through Osborne fractionation, SDS-PAGE, and LC-MS/MS proteomics. The findings highlight the nutritional and functional value of native grains and support their inclusion in health-oriented, gluten-free, and culturally informed food systems.