Agriculture and Food Systems - Research Publications
Now showing items 1-12 of 221
Spatial Variability of Aroma Profiles of Cocoa Trees Obtained through Computer Vision and Machine Learning Modelling: A Cover Photography and High Spatial Remote Sensing Application
Cocoa is an important commodity crop, not only to produce chocolate, one of the most complex products from the sensory perspective, but one that commonly grows in developing countries close to the tropics. This paper presents novel techniques applied using cover photography and a novel computer application (VitiCanopy) to assess the canopy architecture of cocoa trees in a commercial plantation in Queensland, Australia. From the cocoa trees monitored, pod samples were collected, fermented, dried, and ground to obtain the aroma profile per tree using gas chromatography. The canopy architecture data were used as inputs in an artificial neural network (ANN) algorithm, with the aroma profile, considering six main aromas, as targets. The ANN model rendered high accuracy (correlation coefficient (R) = 0.82; mean squared error (MSE) = 0.09) with no overfitting. The model was then applied to an aerial image of the whole cocoa field studied to produce canopy vigor, and aroma profile maps up to the tree-by-tree scale. The tool developed could significantly aid the canopy management practices in cocoa trees, which have a direct effect on cocoa quality.
Evaluation of a tertiary sustainability experiential learning program
Purpose: This paper aims to describe the development, promotion and evaluation of sustainability learning experience database (SLED), a university-curated database of sustainability experiences to augment formal student learning. Its purpose was to encourage students to participate in experiential learning, to facilitate students’ critical appraisal of programs ostensibly designed to create sustainability and to, thus, develop students’ sustainability self-efficacy and employability. Design/methodology/approach: In total, 55 sustainability experiences were curated and placed into the SLED database, which was promoted to students in nine subjects. Supporting materials designed to assist critical evaluation, reflection on experiences and to build student employability were also developed. A comprehensive mixed-methods evaluation of the program was conducted. Findings: The quantitative evaluation revealed some changes in environmental behaviors, depth of critical sustainability thinking and graduate attributes. The qualitative evaluation revealed that students see the value of a university-curated database of experiences and provided ideas for improvements to the database. It also revealed examples of higher-order learning facilitated by SLED. Research limitations/implications: Recruitment and attrition of research subjects, common challenges in pedagogical research, were experienced. “Opt-out” is one response to this but it comes with ethical challenges. Originality/value: This exploratory study demonstrates the potential of SLED to build students’ sustainability efficacy and suggests ways in which it and similar programs can be developed for improved student and sustainability outcomes. Namely, the use of an online platform closely associated with existing learning management systems, higher-level institutional stewardship, closer curriculum integration and close partnering with credentialing programs.
Effect of a mixed silage of king grass (Cenchrus purpureus) and forage legumes (Leucaena leucocephala or Gliricidia sepium) on sheep intake, digestibility and nitrogen balance
(CSIRO Publishing, 2019-09-10)
Ensiled king grass (Cenchrus purpureus (Schumach.) Morrone) is commonly used as feed in tropical ruminant production. However, ruminant performance can be limited by low nitrogen (N) content in tropical grass silage. A mixed feed of legume–king grass silage may be an option to improve ruminant production. We investigated the effects of feeding an ensiled mixture of king grass forage and foliage of a browse tree legume, either leucaena (Leucaena leucocephala (Lam.) de Wit) or gliricidia (Gliricidia sepium (Jacq.) Walp), on dry matter (DM) intake, DM digestibility, organic matter (OM) digestibility and N balance of Pelibuey sheep. Twelve male lambs 9–11 months old were blocked by initial bodyweight (33 ± 3 kg, mean ± s.d.) into three groups of four lambs and randomly assigned to one of three feed treatments: king grass silage (KS); mixed king grass and leucaena silage (KLS); and mixed king grass and gliricidia silage (KGS). Results showed that DM and OM were similar among silages. The N content was higher (P < 0.001) in KLS and KGS than in KS. DM intake and DM digestibility were higher (P < 0.001) in KLS and KGS than in KS. OM digestibility was higher (P < 0.001) in KLS than in KS. Nitrogen intake, faecal N, urine volume, urinary N, digested N, N digestibility, N retention and retained N : N intake ratio from KLS and KGS treatments were higher (P < 0.05) than from KS. A lower (P < 0.01) urinary N : N intake ratio was detected from KGS and KLS than from KS. This study demonstrated that, compared with silage made from king grass alone, legume–king grass silage mixtures can improve intake and nutrient digestibility in Pelibuey lambs. Further, N retention can be enhanced when legume–king grass silages are used as feed compared with king grass silage alone.
Comparison of Phenolic Compounds and the Antioxidant Activities of Fifteen Chrysanthemum morifolium Ramat cv. 'Hangbaiju' in China
(MDPI AG, 2019-08-20)
This study investigated the phenolic compounds of 15 Chrysanthemum morifolium Ramat cv. ‘Hangbaiju’, including 6 ‘Duoju’ and 9 ‘Taiju’, using high performance liquid chromatography (HPLC). The antioxidant activities of these ‘Hangbaiju’ were estimated by DPPH, ABTS and FRAP assays. Results show that a total of 14 phenolic compounds were detected in these flowers, including 3 mono-caffeoylquinic acids, 3 di-caffeoylquinic acids, 1 phenolic acid and 7 flavonoids. ‘Duoju’ and ‘Taiju’ possess different concentrations of phenolic compounds, and ‘Taiju’ exhibits higher caffeoylquinic acids and stronger antioxidant activities than ‘Duoju’. Caffeoylquinic acids show a strong correlation with the antioxidant activities of the samples. Principal component analysis (PCA) reveals an obvious separation between ‘Duoju’ and ‘Taiju’, using phenolic compounds as variables. Apigenin-7-O-glucoside, 3,5-di-O-caffeoylquinic acid, luteolin and acacetin were found to be the key phenolic compounds to differentiate ‘Duoju’ from ‘Taiju’.
Modulation of the human gut microbiota by phenolics and phenolic fiber-rich foods
The gut microbiota plays a prominent role in human health. Alterations in the gut microbiota are linked to the development of chronic diseases such as obesity, inflammatory bowel disease, metabolic syndrome, and certain cancers. We know that diet plays an important role to initiate, shape, and modulate the gut microbiota. Long-term dietary patterns are shown to be closely related with the gut microbiota enterotypes, specifically long-term consumption of carbohydrates (related to Prevotella abundance) or a diet rich in protein and animal fats (correlated to Bacteroides). Short-term consumption of solely animal- or plant-based diets have rapid and reproducible modulatory effects on the human gut microbiota. These alterations in microbiota profile by dietary alterations can be due to impact of different dietary macronutrients, carbohydrates, protein, and fat, which have diverse modulatory effects on gut microbial composition. Food-derived phenolics, which encompass structural variants of flavonoids, hydroxybenzoic acids, hydroxycinnamic acids, coumarins, stilbenes, ellagitannins, and lignans can modify the gut microbiota. Gut microbes have been shown to act on dietary fibers and phenolics to produce functional metabolites that contribute to gut health. Here, we discuss recent studies on the impacts of phenolics and phenolic fiber-rich foods on the human gut microbiota and provide an insight into potential synergistic roles between their bacterial metabolic products in the regulation of the intestinal microbiota.
Dietary fiber-based colon-targeted delivery systems for polyphenols
(Elsevier BV, 2020-06)
Background: Natural polyphenols have potential therapeutic effects on colon-based diseases and gut microbial dysbiosis. However, the delivery of pure polyphenols to the colon has to overcome chemical instability, degradation, and metabolism in the upper gastrointestinal tract after oral ingestion. Dietary fibers have been exploited as microbiota-triggered release systems to protect polyphenols in the upper gut and specifically deliver them to the colon. Scope and approach: This review focuses on the recent development of colon-targeted polyphenol delivery systems using encapsulation technologies based on dietary fibers for both food and pharmaceutical applications. The detailed characteristics and advantages of commonly used dietary fibers and the main mechanisms of encapsulation preparation are discussed. The challenges of targeting the colon and the colonic health benefits of polyphenols are elaborated. In addition, the scope for specific modulation of gut microbiota by the selective combination of polyphenol and dietary fiber is highlighted. Key findings and conclusions: The microbial-triggered release mechanisms of dietary fiber-based delivery systems maintain the structural integrity and protect the polyphenols during passage through the harsh environment of the upper gastrointestinal tract to maximize their concentration in the colonic region. In addition, dietary fibers offer several advantages over other materials for polyphenol encapsulation and delivery, including strong dietary fiber-polyphenol binding interactions, high colonic mucoadhesion, and synergistic prebiotic effects from dietary fiber and polyphenol that result in health benefits for the colon and the body.
Genetic and molecular basis of floral induction in Arabidopsis thaliana
(Oxford University Press (OUP), 2020-05-10)
Many plants synchronize their life cycles in response to changing seasons and initiate flowering under favourable en- vironmental conditions to ensure reproductive success. To confer a robust seasonal response, plants use diverse gen- etic programmes that integrate environmental and endogenous cues and converge on central floral regulatory hubs. Technological advances have allowed us to understand these complex processes more completely. Here, we review recent progress in our understanding of genetic and molecular mechanisms that control flowering in Arabidopsis thaliana.
Diet, Lifestyle and Cardiovascular Diseases: Linking Pathophysiology to Cardioprotective Effects of Natural Bioactive Compounds
Heart and blood vessels disorders comprise one of the main causes of death worldwide. Pharmacologically active natural compounds have been used as a complementary therapy in cardiovascular disease around the world in a traditional way. Dietary, natural bioactive compounds, as well as healthy lifestyles, are considered to prevent coronary artery diseases. Pre-clinical and clinical studies reported that consumption of plant-food bioactive derivatives including polyphenolic compounds, peptides, oligosaccharides, vitamins, unsaturated fatty acids possess protective effects on cardiovascular diseases. This review aims to summarize the cardiovascular risk factors, pre-clinical studies and clinical trials related to cardioprotective properties of the plant-food-derived bioactive compounds. Molecular mechanisms by the natural bioactive compounds exert their cardiovascular protective properties have also been highlighted.
LC-ESI-QTOF/MS characterization of Australian herb and spices (garlic, ginger, and onion) and potential antioxidant activity
Culinary herbs and spices have received great attention as rich sources of polyphenols, which contribute to their putative health benefits. Nevertheless, the comprehensive profiling of these polyphenols in herbs and spices is limited. Therefore, the purpose of this study was to comprehensively characterize phenolic compounds from three commonly consumed Australian herbs and spices, garlic (Allium sativum), ginger (Zingiber officinale), and onion (Allium cepa) using the LC-ESI-QTOF/MS, and to evaluate their antioxidant potential. The LC-ES-QTOF/MS analysis led to the tentative identification of 28, 67, and 118 phenolic compounds in garlic, ginger, and onion, respectively, with flavonoids and phenolic acids being the major components. The obtained results showed that the ginger exhibited highest radical scavenging capacities for the DPPH (0.22 ± 0.01 mg AA/g), ABTS (1.15 ± 0.01 mg AA/g), and ferric reducing capacity (0.08 ± 0.01 mg AA/g) as compared to garlic and onion. In HPLC, garlic contains high concentration of quercetin (>1 mg/g), while onion is enriched in protocatechuic acid (>1 mg/g). The current finding highlights the importance and potential application of garlic, ginger, and onion as ingredients in functional foods, nutraceuticals, and drug development.
A Novel Lens orientalis Resistance Source to the Recently Evolved Highly Aggressive Australian Ascochyta lentis Isolates
(FRONTIERS MEDIA SA, 2017-06-14)
Substantial yield losses and poor seed quality are frequently associated with Ascochyta blight infection of lentil caused by Ascochyta lentis. Recently reported changes in aggressiveness of A. lentis have led to decreased resistance within cultivars, such as Northfield and Nipper in Australia. Furthermore, the narrow genetic base of the current breeding program remains a risk for further selective pathogen evolution to overcome other currently used resistances. Therefore, incorporation of potentially novel and diverse resistance genes into the advanced lines will aid to improve cultivar stability. To identify these, 30 genotypes sourced from five wild species (Lens orientalis, L. odomensis, L. ervoides, L. nigricans and L. lamottei), including eight previously reported resistance sources, were screened for disease reaction to two recently isolated and highly aggressive isolates. Subsequently, two L. orientalis accessions were found highly resistant and a further six L. nigricans, one L. odomensis, one L. ervoides, one L. lamottei, and one L. orientalis accessions were moderately resistant. Several of these were more resistant than the currently deployed resistance source, ILL 7537. Furthermore, L. orientalis accession ILWL 180 was consistently resistant against other highly aggressive isolates recovered from diverse geographical lentil growing regions and host genotypes, suggesting stability and potential for future use of this accession in the Australian lentil breeding program.
Evaluation and identification of wild lentil accessions for enhancing genetic gains of cultivated varieties.
(Public Library of Science, 2020)
Domesticated lentil has a relatively narrow genetic base globally and most released varieties are susceptible to severe biotic and abiotic stresses. The crop wild relatives could provide new traits of interest for tailoring novel germplasm and cultivated lentil improvement. The primary objective of this study was to evaluate wild lentil accessions for identification of economically viable agro-morphological traits and resistance against major biotic stresses. The study has revealed substantial variations in seed yield and its important component characters. Further, the diversity analysis of wild accessions showed two major clusters which were bifurcated into sub-clusters, thereby suggesting their wider genetic divergence. However, principal component analysis exhibited that seed yield plant-1, number of seeds plant-1, number of pods plant-1, harvest index and biological yield plant-1 contributed significantly to the total genetic variation assessed in wild lentil taxa. Moreover, some of the wild accessions collected from Syria and Turkey regions showed resistance against more than one disease indicating rich diversity of lentil genetic resources. The identification of most promising genotypes carrying resistance against major biotic stresses could be utilized in the cultivated or susceptible varieties of lentil for enhancing genetic gains. The study has also identified some trait specific accessions, which could also be taken into the consideration while planning distant hybridization in lentil.
LC-ESI-QTOF/MS Characterization of Phenolic Compounds from Medicinal Plants (Hops and Juniper Berries) and Their Antioxidant Activity
Hops (Humulus lupulus L.) and juniper berries (Juniperus communis L.) are two important medicinal plants widely used in the food, beverage, and pharmaceutical industries due to their strong antioxidant capacity, which is attributed to the presence of polyphenols. The present study is conducted to comprehensively characterize polyphenols from hops and juniper berries using liquid chromatography coupled with electrospray-ionization quadrupole time-of-flight mass spectrometry (LC-ESI-QTOF/MS) to assess their antioxidant capacity. For polyphenol estimation, total phenolic content, flavonoids and tannins were measured, while for antioxidant capacity, three different antioxidant assays including the 2,2-diphenyl-1-picrylhydrazyl (DPPH) antioxidant assay, the 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical cation decolorization assay and the ferric reducing-antioxidant power (FRAP) assay were used. Hops presented the higher phenolic content (23.11 ± 0.03 mg/g dw) which corresponded to its strong antioxidant activity as compared to the juniper berries. Using LC-ESI-QTOF/MS, a total of 148 phenolic compounds were tentatively identified in juniper and hops, among which phenolic acids (including hydroxybenzoic acids, hydroxycinnamic acids and hydroxyphenylpropanoic acids) and flavonoids (mainly anthocyanins, flavones, flavonols, and isoflavonoids) were the main polyphenols, which may contribute to their antioxidant capacity. Furthermore, the HPLC quantitative analysis showed that both samples had a high concentration of phenolic acids and flavonoids. In the HPLC quantification, the predominant phenolic acids in hops and juniper berries were chlorogenic acid (16.48 ± 0.03 mg/g dw) and protocatechuic acid (11.46 ± 0.03 mg/g dw), respectively. The obtained results highlight the importance of hops and juniper berries as a rich source of functional ingredients in different food, beverage, and pharmaceutical industries.