Dr Heather Shewan

Heather attained her Bachelor of Technology degree in food engineering from Massey University in 1999. She then spent 10 years in gelatine manufacture in a variety of roles including quality assurance, production management and process improvement engineering before returning to academia to start a PhD in 2010. In 2015 she completed her PhD study into the rheology of biopolymer soft particle suspensions, supervised by Professor Jason Stokes at the University of Queensland. She has since continued at UQ in postdoctoral roles investigating the relationship between rheological properties, food structure and sensory perception of both real food products and model soft particle suspensions.

Projects Dr Heather Shewan is involved with:

Publications contributed to by Dr Heather Shewan:

  • Chemical composition of bunya nuts (Araucaria bidwillii) compared to Araucaria angustifolia and Araucaria araucana species

    24 January 2023

    (2022) Chemical composition of bunya nuts (Araucaria bidwillii) compared to Araucaria angustifolia and Araucaria araucana species

    Three of nineteen Araucaria tree species from around the world produce large edible seeds. While composition is established for edible pinhão and piñones nuts from Brazil and Chile, respectively, the first detailed characterisation for the composition of edible Araucaria bidwillii (bunya nut) from Australia is provided. Almost half of the kernel weight is moisture and the main component in the dried kernel is starch. Whilst low in protein and fat, it contains all essential amino acids and half the fatty acids are polyunsaturated (Omega-3 and 6). Bunya nuts are a source of dietary fibre, folate and minerals (Cu, Mn, Fe, Mg), while the nut husks and inner coating are high in phenolics, mainly catechin. The composition supports the Traditional Knowledge of Aboriginal Australians that the bunya nut is an energy dense and nutrient rich food. Similarities in the composition among the three different edible varieties were found, which should assist in developing sustainable value chain propositions via shared knowledge on processing and utilisation.

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  • Sensory properties of Australian bunya nuts

    3 June 2022

    (2022) Sensory properties of Australian bunya nuts

    Bunya nuts are the seeds of Araucaria bidwillii, a conifer native to South-East Queensland, Australia. They are one of the 19 species of Araucaria family found around the world, with the nuts from South America being the most commonly consumed. They are traditionally eaten boiled or roasted. This study aims to profile the sensory properties of bunya nuts with chestnut as a comparator. Since chestnuts do not come from a conifer tree, it is expected that there will be differences. Different methods of preparation are also expected to change the sensory attributes. Representative samples were collected from a variety of locations in South-East Queensland, prepared and presented to a panel of 14 experienced tasters applying conventional sensory descriptive profiling. During training, the panel developed a lexicon of 23 sensory attributes together with definitions and reference. Profiles of the boiled and roasted bunya nuts revealed higher scores for hardness on the first bite than chestnuts and, when chewed, became more crumbly, dry, and grainy. They had a savory aroma and flavor, and roasted samples exhibited a roasted aroma. Bunya nut samples were less sweet than chestnut samples. Differences in the sensory properties due to method of preparation were also observed. Boiled bunya nuts were softer and moister, with lower scores for crumbly and grainy. This research is foundational in providing technical information on the sensory profile of this important Indigenous Australian nut and provides a strong basis to support novel food sector opportunities for the bunya nut as a reemerging food source not only in Australia, but also South America. PRACTICAL APPLICATION: There is an increase demand for local, sustainable, and natural foods. Bunya nuts are native to Australia and are part of the Araucaria family, which includes 19 species that can be found around the world. To the best of our knowledge there is no study characterizing Araucaria nuts in terms of sensory attributes. This study builds a lexicon for bunya nuts and compares to chestnuts. It also shows how different preparation methods affect its sensory attributes, as well as possible future uses in product development. The outcomes might provide information to support studies on Araucaria nuts in other countries.

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