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Publications
Publications (50)
Fourier-transform near infrared spectroscopy (FT-NIR) has been used in assessment of sectioned or pulverised teeth, and some consideration has been given to intact teeth in context of demineralisation and decay. This study considered the use of FT-NIR for characterization of sound (undecayed) intact teeth, both inside and outside custody bags. Repl...
Short wave near infrared spectroscopy has found use in non-invasive assessment of dry matter content (DMC, % fresh weight) of mango fruit, both as a guide to harvest maturity and ensure eating quality of ripened fruit. In this study, this application is optimised in terms of pre-processing of spectra, the source of variations important to model per...
Avocado flesh dry matter content (DMC) is an index of eating quality of ripened fruit, and DMC is also related to fruit maturity, with a (cultivar dependant) minimum DMC recommended for harvest. Based on DMC variation within the fruit, the outer equatorial region of the fruit was chosen for optical and physical sampling. Three handheld near infrare...
Automated latent variable selection by Y-Variance threshhold for LOCAL PLS with selection of spectra by LV's scores distances, termed Local Optimized by Variance Regression (LOVR). Technique is compared against other LOCAL, linear and non-linear modelling techniques in terms of prediction accuracy (RMSEP) and computation time (calibration and predi...
As production volume has increased in Australia, increased focus has been given to quality, particularly to managing the timing of harvest. A web based support tool was developed for the Australian mango industry that automates the heat sum measurement process for maturity estimation (from a wireless temperature sensor in orchard) and captures data...
A near infrared spectroscopic method was used to non-invasively assess dry matter (DM) of fruit on tree with a R²p = 0.82 and RMSEP = 0.52% across fruit from a range of water denied treatments. A variety of techniques for manipulating tree fruit carbohydrates (fruit thinning, girdling, nitrogen and water manipulation) were implemented on six mango...
The utility of a handheld visible-short wave near infrared spectrophotometer utilising an interactance optical geometry was assessed in context of the noninvasive determination of intact tomato dry matter content, as an index of final ripe soluble solids content, and colouration, as an index of maturation to guide a decision to harvest. Partial lea...
Certain cultivars of apple are prone to an internal flesh browning defect following extended controlled atmosphere storage. A number of (destructive) reference methods were assessed for scoring the severity of this defect in a fruit, including visual assessment, image analysis (% cross section area affected), International Commission on Illuminatio...
Agave tequilana is a potential biofuel crop, for which the characters of juice total soluble sugar content (TSS), dry matter content (DM), cellulose, hemicellulose and lignin content are quality criteria. Spectra of leaves were obtained using a hand-held silicon photodiode array (Si PDA)-based spectrometer with a wavelength range of 300-1100 nm and...
There is a trend to take instrumentation from the laboratory to the field, e.g., a range of spectrophotometers are commercially available for in field assessment of fruit attributes. Unfortunately, field users tend to place less emphasis on instrument maintenance, so understanding performance issues is important. Deterioration of lamp output qualit...
Retailers commonly stipulate rejection of apple fruit lots with incidence of internal browning. However, the current assessment protocols are based on destructive assessment of a few fruit per lot, and are thus unreliable. The performance of an internal defect sorting system is described in context of assessment of this disorder, in terms of the im...
Spectral indices can be used in assessment of pigment level of intact plant material, and thus there exists the possibly of using spectral indices as a measure of fruit maturity and ripeness. Spectra of tomato, banana and mango fruit were collected with a Nirvana handheld unit (Integrated Spectronics, Australia). A number of spectral indices: green...
The use of a short wave near infrared spectroscopic instrument for estimation of mango fruit DM on tree, as a support in the decision to harvest, was confirmed. The technique was robust in face of change in ambient temperature and light. Agronomic treatments of water stress and fruit removal are recommended for fruit DM increase. The DA meter readi...
Bananas (Musa sp. [AAA group, Cavendish subgroup] 'Williams') grown under paper bunch covers appear riper, being a lighter shade of green at maturity, than fruit grown under plastic bunch covers. However, such fruit ripen more slowly than fruit under plastic, in terms of respiration rate and ethylene release, based on measurements of individual fin...
The feasibility of assessing microalgal fatty acid composition using near-infrared spectroscopy (NIRS) is described. The chlamydomonad microalga, Rhopalosolen saccatus (previously known as Characium saccatum), was isolated from the Fitzroy River, Central Queensland, Australia. R. saccatus was grown in batch culture with varying phosphorus nutrition...
Sample temperature is well known to impact model performance for prediction of chemical attributes in high-moisture-content samples when using short-wave near infrared spectroscopy. A number of methods proposed to reduce this effect were compared in this study. A short-wave near infrared spectroscopy system operating in transflectance geometry was...
Partial least-squares regression models were developed using spectra of tomato fruit collected at 15 degrees C and tested on spectra of an independent set of fruit at higher sample temperatures. The influence of sample temperature on the model used to predict fruit dry matter (DM) was manifested primarily in terms of bias, not standard error of pre...
Current methods for determining the maturity of vanilla (Vanilla planifolia Andrews) beans are unreliable. Yellowing at the blossom end, the current index, occurs before beans accumulate maximum glucovanillin concentrations. Beans left on the vine until they turn brown have higher glucovanillin concentrations but may split and have low quality. To...
The technique of near and short wave near-infrared spectroscopy was assessed with respect to analysis of dry matter and lipid content of microalgae with potential for biodiesel production. Microalgal culture samples were filtered through GF/C filter papers and spectral measurements of wet and oven dried (60 °C overnight) filter papers over the rang...
This paper extends a previous study on the use of image analysis to automatically estimate mango crop yield (fruit on tree) (Payne et al., 2013). Images were acquired at night, using artificial lighting of fruit at an earlier stage of maturation (‘stone hardening’ stage) than for the previous study. Multiple image sets were collected during the 201...
Short wave near infrared (interactance geometry)
spectroscopy is used in assessment of various attributes of intact
fruit. As sample temperature impacts the water peak, the
performance of fruit Brix (soluble sugar) and dry matter models is
perturbed. Addition of a relatively small number of spectra of the
same set of samples at different temperatur...
A purpose designed hand-held spectroscope ("Nirvana", Integrated Spectronics) was used to assess mango fruit pigmentation (flesh and skin) and flesh dry matter content. Fruit dry matter content and flesh colour was assessed of fruit on the tree, and used as indices of fruit maturity. Dry matter of fruit at harvest was also closely related to total...
This paper presents an approach to count mango fruit from daytime images of individual trees for the purpose of a machine vision based estimation of mango crop yield. Images of mango trees were acquired over a three day period, 3 weeks before commercial harvest occurred. The fruit load of each of fifteen trees was manually counted, and these trees...
The dry-extract system for (near) infrared (DESIR) technique was implemented using reflectance near-infrared spec-troscopy in context of detection of contact pesticide residues on fruit. Based on chemical structure, spectra features and regression statistics for PLSR models, a product containing metiram and pyraclostrobin was chosen from six pestic...
Interactance spectra (700-1100 nm) of intact fruit possess features interpreted as being due to the dilution and perturbation of water OH stretching and combination bands (with the second and third overtones of OH stretching at 960 nm and 740 nm, respectively), while the contribution from citric acid CH2 and OH stretching and combination bands are...
The prediction accuracy of models based on visible-short wavelength near infrared spectra (VIS–SWNIR; 500–1050nm) collected from intact fruit using a partial transmittance optical geometry was considered for dry matter (DM) and total soluble solids (TSS) content of mesocarp tissue of banana (Musa acuminata, cv. Robusta) and mango (Mangifera indica,...
Variation in oil content and fatty acid profile (FAP) of Calophyllum inophyllum; a potential biodiesel feedstock species were studied at different maturity stages and biodiesel quality parameters were estimated based on the FAP. A steady increase in oil content was observed with maturity. Variation in palmitic (16:0) and linoleic (18:2) acids follo...
Oxygation, understood as the use of aerated irrigation water with sub-surface drip irrigation, has been documented to benefit growth of a range of crops, particularly on heavier soils. For this research, this technology was applied to pineapple (Ananas comosus) on a loamy sand at Yeppoon, Australia. Two treatments, irrigation with and without oxyga...
Deterioration of lamp output quality over time and degradation of detector signal-to-noise ratio are issues associated with ageing of a spectrophotometer. To document the effect of instrument ageing on short wavelength near infrared spectroscopy-based assessment of internal attributes of fruit quality prediction (total soluble solids, TSS, of juice...
The sweet diterpene glycosides extracted from the leaves of Stevia rebaudiana (Bert) Bertoni are of increasing interest in recent years as possible sugar substitutes. Our objectives were to investigate the application of near infrared reflectance spectroscopy (NIRS) in analysis of steviol glycosides (SGs) concentration (w/w) dry basis in S. rebaudi...
A sound velocity technique and visible–short wave near infrared (400–1100nm) interactance spectroscopy were considered in the context of the assessment of fruit firmness in intact banana, mango and peach fruit. The velocity of a vibration (‘sound’) wave moving through the fruit decreased during ripening of mango (from 84 to 39ms−1), banana (29 to 1...
The utility of short-wavelength near-infrared spectroscopy (over the wavelength region 750–950 nm), used in a partial transmittance
optical geometry, was assessed as a means of estimating the dry matter concentration of potato tubers. The sampling optics
did not involve contact with the sample, and could be used on a moving stream of product. A pre...
Short wave near infrared (SWNIR) (400–1100nm) spectroscopy was trialled in assessment of mango (Mangifera indica L.) fruit maturation and as a harvest time guide to final eating quality. Fruit maturity was indexed in terms of flesh colour (r2=0.79 for Hunter b value against maturity score), dry matter content (r2=0.66 for % DM against maturity scor...
A total of 179 garlic (Allium sativum L.) accessions were collected from various parts of Nepal in 2000. Each accession was planted in each of a plot of 2.25m2 at the Institute of Agriculture and Animal Science (IAAS) Horticulture farm (225m asl) and at the Agriculture Research Station,
Dailekh (1400m asl) of Nepal Agriculture Research Council (NAR...
This paper summarises an adoption study of 15 improved technologies in agriculture, horticulture, livestock and forestry production conducted in the western hills of Nepal in 1994/1995. Data are analysed and interpreted using uni and multi-variate statistical methods to provide household adoption profiles and to identify important factors affecting...
Tomato cultivation in rainy season is being endangered and is becoming less profitable because of tomato yellow leaf curl virus (TYLCV) infection. Studies were conducted at Agriculture Research Station, Lumle to assess the incidence of TYLCV and associated yield losses in various commercial tomato growing pockets of the western hills during the per...