The Application of Near Infrared Spectroscopy for the Assessment of Avocado Quality Attributes

[Extract] Quality and safety evaluation of agricultural products has become an increasingly important consideration in market/commercial viability and systems for such evaluations are now demanded by customers, including distributors and retailers. Unfortunately, most horticultural products struggle with delivering adequate and consistent quality to the consumer. Removing inconsistencies and providing what the consumer expects is a key factor for retaining and expanding both domestic and international markets. Most commercial quality classification systems for fruit and vegetables are based on external features of the product, for example: shape, colour, size, weight and blemishes. However, the external appearance of most fruit is generally not an accurate guide to the internal or eating quality of the fruit. Internal quality of fruit is currently subjectively judged on attributes such as volatiles, firmness, and appearance. Destructive subjective measures such as internal flesh colour, or objective measures such as extraction of juice to measure sweetness (°Brix) or assessment of dry matter (DM) content are also used, although obviously not for every fruit – just a sample to represent the whole consignment

Novel method for shark age estimation using near infrared spectroscopy

Accurate age determination is an important component of assessing and managing fish populations, yet traditional ageing using growth bands is time-consuming and has limitations. In the present study, an alternative approach to shark age estimation using near infrared spectroscopy (NIRS) was investigated using two species. The ages of Sphyrna mokarran and Carcharhinus sorrah vertebrae that had been traditionally aged and validated were successfully predicted up to 10 years of age using NIRS. The correlations between the known ages of the vertebrae and their near infrared spectra were strong, with R2 values of 0.89 and 0.84 for S. mokarran and C. sorrah respectively. The major advantage of the NIRS ageing approach was the rapid speed of age estimation, which could enable large numbers of sharks to be aged quickly. This would offer the fisheries management benefit of improving the reliability of age information for stock and risk assessments

Age estimation of barramundi (Lates calcarifer) over multiple seasons from the southern Gulf of Carpentaria using FT-NIR spectroscopy

The age of whole otoliths from barramundi (Lates calcarifer) obtained from the southern Gulf of Carpentaria were estimated using Fourier transform near-infrared (FT-NIR) spectroscopy. Otoliths from 1716 barramundi collected in 2006, 2009 and 2012–2015 were used in this study. Partial least-squares regression models (PLS-R) and multiple linear regression models (MLR) were developed from the diffuse reflectance spectra and the age was obtained from traditional sectioned otoliths. Calibration models were built up over consecutive years (2012–2015) by using a subset of the samples and used to predict the age of the remaining samples and samples from the following year. Results suggest that when seasonal (temporal) variability is incorporated into the calibration model, FT-NIR has the ability to predict barramundi age (validation R2 ranged from 0.73 to 0.78; RMSEP ranged from 6.92 to 7.64 months). The predicted age class was within 1 year of the reference age in over 96% of the samples. These models were also able to predict the age of otoliths from 2006 and 2009, which were retrieved from long-term storage (validation R2 ranged from 0.77 to 0.84; RMSEP ranged from 8.66 to 10.88 months). The results from this study have shown the potential for barramundi from the southern Gulf of Carpentaria to be aged quickly and accurately by using FT-NIR

A novel method for the age estimation of Saddletail snapper (Lutjanus malabaricus) using Fourier Transform-near infrared (FT-NIR) spectroscopy

Near infrared (NIR) spectroscopy was investigated as a potential rapid method of estimating fish age from whole otoliths of Saddletail snapper (Lutjanus malabaricus). Whole otoliths from 209 Saddletail snapper were extracted and the NIR spectral characteristics were acquired over a spectral range of 800–2780 nm. Partial least-squares models (PLS) were developed from the diffuse reflectance spectra and reference-validated age estimates (based on traditional sectioned otolith increments) to predict age for independent otolith samples. Predictive models developed for a specific season and geographical location performed poorly against a different season and geographical location. However, overall PLS regression statistics for predicting a combined population incorporating both geographic location and season variables were: coefficient of determination (R2) = 0.94, root mean square error of prediction (RMSEP) = 1.54 for age estimation, indicating that Saddletail age could be predicted within 1.5 increment counts. This level of accuracy suggests the method warrants further development for Saddletail snapper and may have potential for other fish species. A rapid method of fish age estimation could have the potential to reduce greatly both costs of time and materials in the assessment and management of commercial fisheries

Revolutionising Fish Ageing: Using Near Infrared Spectroscopy to Age Fish

The project aimed to evaluate the innovative application of NIRS as a reliable, repeatable, and cost-effective method of ageing fish, using otoliths of Barramundi and Snapper as study species. Specific research questions included assessing how geographic and seasonal variation in otoliths affects NIRS predictive models of fish age, as well as how the NIR spectra of otoliths change in the short-term (i.e., <12 months) and long-term (i.e., historical otolith collections) and what effect this has on the predictive ability of NIRS models. The cost-effectiveness of using NIRS to supplement standard fish ageing methods was also evaluated using a hypothetical case study of Barramundi

Barramundi origins : Determining the contribution of stocking to the barramundi catch on Queensland’s east coast

Researchers from Queensland’s Department of Agriculture and Fisheries, James Cook University, and the University of Western Australia tested a range of otolith-based and genetic methods to identify hatchery-born from wild-born Barramundi. The project took place in the Dry Tropics region, where extensive historical and ongoing impoundment stocking (release of hatchery-born Barramundi into freshwater bodies) may be contributing to the downstream wild-capture marine and estuarine fishery. Fish samples were collected from the commercial and recreational wild-capture marine and estuarine fishery in 2019 and 2020, following the major Townsville floods in February 2019. The team identified a cost-effective means of using trace elements in fish otoliths to reliably distinguish hatchery-origin from wild-origin fish, measure the contribution of stocked fish to the wild population, and assess the sustainability of the wild-capture fishery

Impact assessment and prediction of rot susceptibility of Hass avocado fruit using FT-NIR spectroscopy

[Extract] Avocado fruit maturity and quality characteristics are often variable and this results in variation within a shipment in ripening rates, shelf-life and quality. Retail and consumer surveys over the last 15+ years have shown that consumers are not always satisfied with avocado quality, mainly because of poor flesh quality that can not be determined until the fruit is cut. The surveys show that only 30% of the Australian population eat avocados and they expect to discard one in every four pieces of fruit they purchase because of poor internal quality. Other reasons contributing to reduced consumption include concerns over spoilage, convenience, price and limited availability. The surveys revealed that consumers select bruising as the major defect, followed by body and stem end rots. Bruising was found to be a more important barrier to purchasing than price. Thus, fruit quality reliability is a key factor impacting on supply chain efficiency and related profitability

Non-invasive assessment of avocado quality attributes

Avocado fruit maturity and quality characteristics are often variable resulting in variation within a shipment in ripening rates, shelf-life and quality. Inferior fruit quality is seen as one of the key factors impacting on supply chain efficiency and profitability (Margetts 2009). Consumer surveys show that only 30% of Australian’s eat avocados and that they expect to discard one in every four pieces of fruit they purchase because of poor internal quality (Avocados Australia Limited and Primary Business Solutions 2005). Surveys reveal that consumers prefer avocado fruit with at least 25% dry matter (DM) (Harker et al. 2007) and select bruising as the major defect, followed by rots (Harker 2009). Research has shown that if a consumer is dissatisfied with fruit quality then that consumer will not purchase that commodity for another 6 weeks (Embry 2009). To expand domestic and international sales the industry must be able to supply the discerning and demanding consumer with a consistent high quality product. Therefore a rapid non-destructive system that can accurately and rapidly monitor avocado quality attributes would allow the industry to provide better, more consistent eating quality fruit to the consumer, thus improving industry competitiveness and profitability.\ud This paper presents the current research findings of developing a non-invasive near infrared spectroscopy assessment tool which uses optical light for detecting bruises and for predicting both avocado DM content and rot susceptibility as an indication of shelf-life

A novel use of near infrared spectroscopy: ageing deepwater sharks

To age sharks, the growth bands in the shark vertebrae (like the rings in a tree) or on the spines in front of each dorsal fin (which only some sharks have) are manually counted using a microscope. This is time-consuming and is only possible on dead animals. NIR spectroscopy is shown to be able to detect age in dorsal fin spines of sharks and hand-held NIR spectroscopy units could potentially be used for ageing of sharks in the field, at sea, using a hand-held unit to scan the fin spine on a live animal

Impact assessment and prediction of rot susceptibility of Hass avocado fruit using FT-NIR spectroscopy

[Extract] Avocado fruit maturity and quality characteristics are often variable and this results in variation within a shipment in ripening rates, shelf-life and quality. Retail and consumer surveys over the last 15+ years have shown that consumers are not always satisfied with avocado quality, mainly because of poor flesh quality that can not be determined until the fruit is cut. The surveys show that only 30% of the Australian population eat avocados and they expect to discard one in every four pieces of fruit they purchase because of poor internal quality. Other reasons contributing to reduced consumption include concerns over spoilage, convenience, price and limited availability. The surveys revealed that consumers select bruising as the major defect, followed by body and stem end rots. Bruising was found to be a more important barrier to purchasing than price. Thus, fruit quality reliability is a key factor impacting on supply chain efficiency and related profitability