Joel Johnson

• Master of Science
• PhD Student at The University of Queensland

This study applied response surface methodology (RSM) to optimise process parameters for rum fermentation. The primary aim was to enhance ethanol productivity through refined molasses conditioning and fermentation. Polyacrylamide flocculants were evaluated for molasses clarification, identifying an optimised blend which significantly outperformed i...

Nigella sativa L. (generally known as black cumin) is a medicinal plant prized for its therapeutic and nutritional benefits. Its seed oil is used extensively in pharmaceuticals, nutraceuticals, cosmetics, and cooking. However, extracting oil to satisfy the world’s needs leaves behind plenty of solid residues. The seeds of Nigella are loaded with he...

Okra (Abelmoschus esculentus) flowers are a common agriculture by-product across regions in Africa, Asia and the Americas; however, they have considerable value-adding potential as rich sources of health-benefitting anthocyanins. One major barrier standing in the way of this potential is the high pectin content, resulting in viscous extracts which...

Nigella sativa L., which is commonly referred to as black cumin, is a globally recognized plant for the nutraceutical and pharmaceutical values of its seed oil. While numerous studies have investigated Nigella oil, there is a scarcity of information regarding the variation of key phytoconstituents in Nigella oil from diverse seed sources. It is als...

The optimum germination conditions for foxtail millet sprouts enriched with γ-aminobu-tyric acid (GABA) and antioxidant polyphenols were investigated. From single-factor experimental results, both the GABA level and total phenolic content (TPC) were more significantly affected by soaking temperature and time, and concentration of sucrose culture so...

In the original publication [...]

There is increasing interest in Australian finger lime (Citrus australasica) due to its nutritional and bioactive potential. In this study, polar extracts from five finger lime cultivars were investigated for their potential bioactivity using a range of assays: antioxidant capacity (total phenolic content (TPC), ferric reducing antioxidant power (F...

Several additives have been shown to reduce enteric methane emissions from ruminants when supplied in feed. However, utilising this method to deliver such methane-reducing compounds (MRCs) in extensive grazing systems is challenging. Use of livestock drinking water presents a novel method to deliver MRCs to animals in those systems. This work evalu...

Dragon fruit (Hylocereus spp.), renowned for its aesthetic appeal and rich antioxidant content, has gained global popularity due to its numerous health benefits. In Australia, despite growing commercial interest in cultivating dragon fruit, there is uncertainty for local growers stemming from competition with imported varieties. Notably, there is a...

Understanding the extraction process of Nigella oil is crucial due to its significant impact on yield, quality, and therapeutic effectiveness. This study explored the effects of various screw press temperatures (40 °C, 50 °C, 60 °C, 70 °C, and 80 °C) on the quantity and quality of Nigella oil to optimize conditions that maximize yield while maintai...

Land cover analysis is a key method used to understand past land use patterns and explore the driving forces and processes behind them. This study focuses on land cover in 18 counties and cities of Hainan Island, delving into the driving factors of land cover in specific areas of Hainan Island, including the southern, northern, eastern, western, in...

The recent steady demand for products with increased antioxidant properties largely determines the direction of research in the field of creating high-quality products with increased biological value. Insufficient knowledge of the antioxidant activity and potential biological value of whiskey makes this area of research relevant and in demand. This...

The addition of methane-reducing compounds (MRCs) to livestock drinking water presents an alternative method for enteric methane mitigation in extensive systems where these compounds cannot be fed through the diet. This work evaluated several such compounds with the potential to be deployed in this manner. Methane-reducing compounds were selected b...

Nigella sativa, also known as black cumin, is esteemed for its rich reservoir of health-benefitting phytoconstituents nestled within its seeds. The composition of its seeds can be influenced by factors such as genotype diversity and agricultural practices. Understanding these dynamics is important for maximizing the nutritional and medicinal attrib...

This study explored the performance and physiological responses of three commercially used peanut cultivars in Australian farming systems under ambient and elevated CO2 conditions, aiming to identify the most suitable genotype for dual-purpose (grain and graze) cropping experiments. The experiment utilized an open-top chamber (OTC) facility to regu...

Essential Oil (EO) extracted from Rosemary is known for its therapeutic, antifungal, stimulant and antibacterial effects. This study aimed to detect and quantify the adulteration of Rosemary essential oil with different percentages of eucalyptus essential oil, using two analytical techniques: gas chromatography with Flame Ionization Detection (GC-F...

The finger lime [Microcitrus australasica (F. Muell.) Swingle] is a small tree with high economic, culinary, and ornamental value, originating in the rainforests of eastern Australia. This study collected and comprehensively evaluated nine finger lime varieties, characterizing 42 traits across all plant parts (tree, thorns, flowers, fruit). The tes...

Background This study investigated the ultraviolet (UV) absorption spectra of various types and ages of grape wines and the correlation these spectra presented with their phenolic constituents. Firstly, the differences in UV spectra were characterized for different wine samples, depending on their type and age. Methods The following methods were u...

Black rosehip (Rosa pimpinellifolia L.) fruit is a rich source of anthocyanins and has been promoted for several bioactive properties. Drying this fruit can increase its shelf life and enhance its applications in functional food products. This study aimed to optimize the microwave drying process of black rosehip fruit. The process was optimized bas...

Urban Green Spaces provide extensive ecosystem services, benefiting both human and wildlife in urban areas, and improving the overall ecological health of cities. The impact of Urban Green Spaces can be measured through various indicators. This study combined remote sensing data and social surveys to investigate the distribution patterns and drivin...

Urban plants are important for the aesthetics and functionality of the urban environment and are closely related to human life. To help fill the current research void on the distribution patterns and driving mechanisms of urban plant diversity in the tropics, we tested the relationship between plant species richness and land use and anthropogenic a...

Essential Oil (EO) extracted from Rosemary is known for its therapeutic, antifungal, stimulant and antibacterial effects. This study aimed to detect and quantify the adulteration of Rosemary essential oil with different percentages of eucalyptus essential oil, using two analytical techniques: gas chromatography with Flame Ionization Detection (GC-F...

The relationship between individual phytochemical constituents and overall antioxidant capacity or total phenolic content (TPC) is poorly understood in faba bean. This study used a range of linear and nonlinear regression techniques to investigate whether the antioxidant capacity and TPC of 60 faba bean samples (flour and methanolic extracts) could...

Bioprospecting native Australian plants offers the potential discovery of latent and novel bioactive compounds. The promising cytotoxic and antibacterial activity of methanolic extracts of Pittosporum angustifolium and Terminalia ferdinandiana led to further fractionation and isolation using our laboratory’s bioassay-guided fractionation protocol....

Sesame is an emerging crop of interest in Australia and has attracted widespread interest due to the health-benefitting properties of its bioactive compounds, including fatty acids, lignans, and polyphenols. This study aimed to investigate the impact of drought stress on these bioactive compounds, using eleven cultivars of black sesame seeds grown...

Background and Objectives Dry fractionation, combining milling and air classification technology, offers an economical and sustainable pathway for the processing of value‐added protein ingredients from Australia's major pulse crops. Leveraging a wider range of pulses will help meet the growing demand for plant‐based protein ingredients. This study...

The edible, endemic Australian species Alpinia caerulea belongs to the same family as ginger and turmeric. The rhizome and fruit have a mild ginger-like flavour, but there is very little information on its chemical composition or potential biological activities. This study found low levels of ascorbic acid in the fruit and fruit capsule (2.3–3.4 mg...

Bioprospecting native Australian plants offers potential discovery of latent and novel bioactive compounds. Promising cytotoxic and antibacterial activity of methanolic extracts of Pittosporum angustifolium and Terminalia ferdinandiana led to further fractionation and isolation using our laboratory’s bioassay guided fractionation protocol. Hence, t...

Adzuki bean has recently been proposed as a viable dual-purpose (grain-and-graze) crop for the Northern regions of Australia because of its successful use in semi-arid regions and its nitrogen fixation capacity to improve soil fertility and animal nutrition. However, there are very few studies on the phytochemical composition and nutritional value...

The production of high-quality rum requires a carefully controlled fermentation process, which is determined by the physicochemical and nutritional properties of the molasses used as a substrate. The flavor, aroma, and alcohol content of the final product are heavily influenced by the composition of molasses. This paper presents the results of an e...

Cuticular hydrocarbon (CHC) profiling shows promise as a chemotaxonomic tool for identifying and discriminating between closely related insect species. However, there have been limited studies using CHC profiling to differentiate between weevil species (Coleoptera: Curculionidae). This proof-of-concept study investigated the use of CHC and volatile...

Faba bean ( Vicia faba ) is growing in popularity in Australia, partly due to its higher levels of health‐benefiting compounds compared to other grain crops. This study investigated infrared spectroscopy for predicting levels of bioactive compounds such as antioxidants and phenolics in faba bean flour. Calibration models were performed on 60 sample...

Ice cream fruit (Casimiroa edulis La Llave) is a member of the Rutaceae family native to South America, which has recently been introduced to China. In order to improve the yield of ice cream fruit, we carried out a hybridization experiment with paired pollination. Pollen was collected in the morning and carefully stored, before it was applied to t...

This study compared the performance of near-infrared spectroscopy (NIRS) and mid-infrared spectroscopy (MIRS) for the prediction of moisture, protein, total phenolic content (TPC), ferric reducing antioxidant potential (FRAP) and total monomeric anthocyanin (TMA) content in 65 samples of Australian wheat flour. Models were constructed on 50 of the...

Chocolate-coated confectionery, including fruits and nuts, is an increasingly popular snack food. Non-destructive discrimination of the core composition could be useful for quality assurance purposes, such as ensuring the absence of peanuts in a batch of chocolate-coated sultanas. This study investigated the optimum pre-processing methods and discr...

The aim of the present study was to evaluate the potential of handheld near-infrared (NIR) and benchtop mid-infrared (MIR) spectroscopy for the rapid prediction of antioxidant capacity, dry matter, and total phenolic contents in cayenne pepper (Capsicum annuum ‘Cayenne’). Using NIR spectroscopy, the best-performing model for dry matter had an R2pre...

The aim of the present study was to evaluate the potential of handheld near-infrared (NIR) and benchtop mid-infrared (MIR) spectroscopy for the rapid prediction of antioxidant capacity, dry matter, and total phenolic contents in cayenne pepper (Capsicum annuum 'Cayenne'). Using NIR spectroscopy, the best-performing model for dry matter had an R 2 p...

Leaf water content (LWC) is a crucial physiological parameter that plays a limiting role in the efficiency of photosynthesis and biomass production in many plants. This study investigated the use of diffuse reflectance near-infrared spectroscopy (NIRS) for the rapid prediction of the gravimetric LWC in eucalypt leaves from Eucalyptus and Corymbia g...

This study investigated the interrelationships between the parameters of density, optical refraction, the volume fraction of ethanol and the total extract, using model solutions and samples of wine materials. The regularities of changes in refractometer readings in the process of alcoholic fermentation have been studied. The functional dependence o...

Infrared spectroscopy (wavelengths ranging from 750-25,000 nm) offers a rapid means of assessing the chemical composition of a wide range of sample types, both for qualitative and quantitative analyses. Its use in the food industry has increased significantly over the past five decades and it is now an accepted analytical technique for the routine...

Foxtail millet husk (FMH) is generally removed and discarded during the first step of millet processing. This study aimed to optimize a method using deep eutectic solvents (DESs) combined with ultrasonic-assisted extraction (UAE) to extract phenols from FMH and to identify the phenolic compositions and evaluate the biological activities. The optimi...

Profiles of phenolic compounds, antioxidant activities, α-glucosidase inhibitory and anti-glycation activities of nine mulberry varieties were investigated. Twenty-three phenolic components were identified in the mulberry fruit. Chlorogenic was the predominant phenolic acid, while rutin was the most abundant flavonoid. In the colored mulberry fruit...

Tropical fruits play a major role in the economic and social development of Hainan (China). Despite favorable climatic conditions, the yield of tropical fruits in Hainan remains low, in part due to the low genetic potential of currently grown tropical fruit varieties. Consequently, there is a need to improve yield potential by exploiting the genome...

Potato (Solanum tuberosum L.) is one of the most significant vegetable crops grown globally, especially in developing countries. Over the last few years, global potato production has been increasing. This growth has created many opportunities for developing a wide range of value-added products from these crops. However, this requires monitoring the...

Fermented juice from the noni tree (Morinda citrifolia) is a traditional medicinal product used by South Pacific Islanders to treat a wide range of ailments, including cancer, inflammation and obesity, as well as improving overall wellbeing. Many of its bioactive properties have been suggested to arise from the high antioxidant capacity and phenoli...

Habanero chillies (Capsicum chinense cv Habanero) are a popular species of hot chilli in Australia, with production steadily increasing. However, there is limited research on this crop due to its relatively low levels of production at present. Rapid methods of assessing fruit quality could be greatly beneficial both for quality assurance purposes a...

Adulteration of tea tree (Melaleuca alternifolia) oil with cheaper essential oils—such as eucalyptus oil—is a major threat to the Australian tea tree oil industry. Near-infrared spectroscopy may offer a rapid, cheap and non-destructive method of assessing adulteration levels in tea tree oil. In this study, near-infrared (NIR) spectra were collected...

Tebuthiuron is a selective herbicide for woody species and is commonly manufactured and sold as a granular formulation. This project investigated the use of infrared spectroscopy for the quality analysis of tebuthiuron granules, specifically the prediction of moisture content and tebuthiuron content. A comparison of different methods showed that ne...

The Central Queensland region of Australia is a large producer of horticultural produce; however, there are limited studies on the phytochemical composition of the produce from this region. Additionally, some crops or cultivars are poorly known in domestic markets; hence are currently only grown for niche markets. There is opportunity to expand pro...

Background Recent technological progress has bolstered efforts to bring personalized medicine from theory into clinical practice. However, progress in areas such as therapeutic drug monitoring (TDM) has remained somewhat stagnant. In drugs with well-known dose-response relationships, TDM can enhance patient outcomes and reduce health care costs. Tr...

Pure Australian tea tree oil is a high-value commodity; however, cheaper tea tree oils are often adulterated with other substances such as eucalyptus oil. Detection of adulteration typically requires time-consuming analysis with expensive equipment. Consequently, rapid methods of screening for adulteration would be beneficial for the industry. This...

The adsorption and desorption capabilities of eight types of macroporous adsorption resins (MARs) for polyphenols from foxtail millet bran (FMB) extract were investigated. The D101 resin demonstrated the highest adsorption and desorption capacity, followed by the AB‐8, DM301 and ADS‐17 resins. The reaction kinetics for the adsorption of FMB polyphe...

The phytochemistry and anticancer properties of nine Nigella sativa genotypes grown in central Queensland, Australia, were determined and compared. The genotype AVTKS6 recorded the highest seed yield (2195 kg ha⁻¹) and was associated with the highest plant density (112 plants m⁻²), whereas AVTKS8 had the highest harvest index (0.42). The seed yield...

A large variety of unique and distinct flora of Australia have developed exceptional survival methods and phytochemicals and hence may provide a significant avenue for new drug discovery. This study proposes a bioassay guided fractionation protocol that maybe robust and efficient in screening plants with potential bioactive properties and isolating...

This paper presents an analysis of modern methods used to determine antioxidant activity. According to research by the World Health Organization, the deficiency of such important nutrients as antioxidants leads to a decrease in body resistance and the development of chronic diseases. When it comes to diet, the inclusion of foods with a high content...

Abstract Milling and air classification settings were optimised for production of protein concentrates from Australian faba bean, yellow pea and red lentil seed material. Pulses were milled to flour of three progressively finer particle size distributions (D50 of 23–25, 16–18 and 13–14 μm) and air classified at classifier wheel speeds of 7080, 9600...

Consumers of Australian cider are currently trending towards higher-quality cider products. As a result, boutique and craft cider breweries are expected to experience a period of growth over the next five years. Supporting this trend and subsequent growth is paramount to rebuilding the cider industry post-COVID-19. Many current practices and proced...

Eucalypt trees are a key feature of many Australian ecosystems; however, it can be difficult to identify the various species based on their leaves alone. The rapid, non-destructive analytical technique of near-infrared spectroscopy (NIRS) has shown promise for discrimination of similar species in other flora types; thus this study investigated the...

The utilisation of high gravity wort possessing a higher sugar content is frequently used to increase the capacity and efficiency of beer production. In such an environment, osmotic stress, lower nutrient availability, ethanol toxicity and elevated CO2 concentrations may decrease the sustainability of yeast performance and have a negative impact on...

Student learning approaches and level of engagement with the learning resources presented can have a significant impact on their overall understanding of the topic contents and their success in assessment items. This study used the student course engagement questionnaire (SCEQ) to assess the level of engagement of first-year undergraduate students...

With an increasing demand for the efficient use of farmland resources, there is growing interest in value-adding to crops through using them or their by-products in various food processing industries. Adzuki bean is one emerging crop which shows promise for use in the value-adding chain; however, there is limited information on the phytochemical co...

Adzuki bean (Vigna angularis) is currently a minor crop in Australia, with less than 5000 tons harvested p.a. However, there is potential to expand production in the northern regions of Australia if suitable cultivars are available. This study used liquid chromatography coupled with tandem mass spectroscopy (LC-MS/MS) to investigate the polyphenoli...

Modelling the dispersion of atmospheric pollutants plays an important role in regulatory and epidemiological settings. Although the majority of modelling concepts were developed in the 1980s, a significant amount of optimisation and refinement of dispersion models has occurred since this time. In addition, some completely novel models such as compu...

Edible oil blends are composed of two or more edible oils in varying proportions, which can ensure nutritional balance compared to oils comprising a single component oil. In view of their economical and nutritional benefits, quantitative analysis of the component oils in edible oil blends is necessary to ensure the rights and interests of consumers...

Ginger is well known for its unique pungent flavour and numerous health benefits, both of which can be attributed to the gingerol derivatives. Quantification of these compounds is important for assessing ginger quality for processing purposes, as their levels can vary with cultivar and growing conditions. However, current analytical techniques are...

This proof-of-concept study aimed to investigate the potential of using near infrared (NIR) spectroscopy to discriminate between genera of Gonipterini weevil. NIR spectra (10,000–4,000 cm ⁻¹ ) were collected from 15 Gonipterini specimens, comprising three genera and five species. Principal component analysis (PCA) highlighted the inter-specific var...

Burdekin plum (Pleiogynium timoriense) is a widespread native edible fruit from Australia; however, there are limited studies exploring the chemical composition of this species. This study investigated the phytochemical composition of Burdekin plum flesh and seeds, finding a high antioxidant activity (12,571 mg Trolox equivalents/100 g as Ferric Re...

Essential oil distilled from Melaleuca alternifolia leaves, commonly known as tea tree oil, is well known for its biological activity, principally its antimicrobial properties. However, many samples are adulterated with other, cheaper essential oils such as eucalyptus oil. Current methods of detecting such adulteration are costly and time-consuming...

Pulse crops form a major part of the Australian cropping sector, which is currently valued at approximately AUD $61 billion. Many of these crops contain high levels of health-benefiting compounds, such as phenolics and other antioxidants. Consequently, in recent years there has been increasing interest in marketing them as "functional foods"-which...

Although Australia has over 6000 species of native foodplants and botanicals, only 18 native foods are currently under commercial production. One of the few Australian species grown internationally is macadamia, which is worth over AU $2 billion across the globe. Many of our native foodplants can also be classified as functional foods: foods which...

Ginger (Zingiber officinale) is best known for its pungent, aromatic flavour; however, it also provides numerous health benefits. It is currently a niche crop in Australia, with an annual farmgate value of AUD $32 million. Consequently, there has been limited research performed on the chemistry of Australian ginger to date. This study aimed to prov...

A large variety of unique and distinct flora of Australia have developed exceptional survival methods and phytochemicals and hence may provide a significant avenue for new drug discovery. Several literatures have identified some native Australian plants as having high therapeutic potential. Despite this, the bioactive compounds of some of these spe...

The therapeutic and medicinal properties of sesame and its products may be attributed to the high levels of health-promoting compounds found in this crop. The key classes of bioactive compounds in sesame seeds are phenolics and lignans; however, there is limited information available about the level of these compounds in Australian-grown sesame. Tw...

The high anthocyanin content of plums is one major contributor toward their well-known health-benefiting effects. Consequently, rapid methods for measuring anthocyanin content would be greatly beneficial for quality assurance purposes. However, there are no applications of infrared spectroscopy for the prediction of anthocyanin content in solvent e...

This chapter examines the applications of nanomaterials onto electrochemical sensors for nutrient-N species in the literature over the last 5 years. The chapter starts by discussing the two central bottom-to-top and top-to-bottom tenets to nanostructure synthesis. It then examines the use of nanomaterials in general chemical analyses, followed by r...