Real-time nondestructive citrus fruit quality monitoring system: development and laboratory testing

This study reports on the development and laboratory testing of the This study reports on the development and laboratory testing of the nondestructive citrus fruit quality monitoring system.  Prototype system consists of a light detection and ranging (LIDAR) and visible-near infrared spectroscopy sensors installed on an inclined conveyer for real-time fruit size and total soluble solids (TSS) measurement respectively.  Laboratory test results revealed that the developed system is applicable for instantaneous fruit size (R2 = 0.912) and TSS (R2 = 0.677, standard error of prediction = 0.48 °Brix) determination.  Future applications of such system would be in precision farming for in-field orange quality determination during the harvest and for row specific yield mapping and monitoring.    Keywords: LIDAR sensor, visible-near infrared spectroscopy, fruit size, sugar conten

Sensors for product characterization and quality of specialty crops—A review

This review covers developments in non-invasive techniques for quality analysis and inspection of specialty crops, mainly fresh fruits and vegetables, over the past decade up to the year 2010. Presented and discussed in this review are advanced sensing technologies including computer vision, spectroscopy, X-rays, magnetic resonance, mechanical contact, chemical sensing, wireless sensor networks and radiofrequency identification sensors. The current status of different sensing systems is described in the context of commercial application. The review also discusses future research needs and potentials of these sensing technologies. Emphases are placed on those technologies that have been proven effective or have shown great potential for agro-food applications. Despite significant progress in the development of non-invasive techniques for quality assessment of fruits and vegetables, the pace for adoption of these technologies by the specialty crop industry has been slow

The biochemical basis of colour as an aesthetic quality in Citrus sinensis.

Thesis (M.Sc.Agric.)- University of Natal, Pietermaritzburg, 2001.The development of fruit colour in the sweet orange (Citrus sinensis) is a cultivar characteristic affected by climate and environment. Although external colour is not always an indication of internal quality or maturity, it is probably the most important factor determining consumer acceptance. In the present investigation, efforts were made to determine the biochemical basis of colour as an aesthetic quality in C. sinensis 'Navel' and 'Valencia'. Furthermore, the changes in pigment content and composition during the period of colour development were recorded. Finally, in an attempt to manipulate citrus colour, the effect of dehydrating agents (alcohols), plant hormones, micro-nutrients and low temperature on flavedo carotenoid content was determined. Saponification of the two major colour-imparting components resolved by thin layer chromatography, followed by reversed-phase high performance liquid chromatography revealed that the principal colour-imparting pigments in C. sinensis flavedo are the yellow-coloured xanthophyll 9-Z-violaxanthin and the red C(30) apocarotenoid β-citraurin. Both pigments occur in the flavedo in esterified form. Identification of the chromophores was based on co-chromatography and online spectral analysis. The colour quality of mature fruit was dependant on the content and relative amounts of 9-Z-violaxanthin and Pcitraurin. Quantitative results revealed that increased colour intensity of citrus flavedo was associated with a decline in the 9-Z-violaxanthin : β-citraurin ratio from greater than 50 to below 10, and an increase in 9-Z-violaxanthin and β-citraurin content. Measurement of the mass and ratio of these pigments can be used to accurately colour-grade orange fruit for local and export markets. These parameters will also aid in the evaluation of colour manipulatory techniques. Visual colour break in C. sinensis appears to be associated with a minimum in total pigment as well as total carotenoid content. The period prior to colour break is characterised by a reduction in chlorophylls, carotenes and free xanthophylls usually associated with photosynthetic activity. Following colour break, a massive increase in xanthophyll acyl esters (particularly 9-Z-violaxanthin) is observed. Efforts were made to manipulate carotenoid content of citrus flavedo in vivo, with a view to manipulate fruit colour commercially. It was shown that the micro-nutrients tungsten and molybdenum, and the plant hormones abscisic acid and jasmonic acid increased carotenoid content of flavedo discs; whereas the plant hormone gibberellic acid decreased carotenoid levels. The dehydrating agents ethanol and butanol increased carotenoid content in whole fruit flavedo and flavedo discs. Optimum concentrations were shown to be 20-30% (v/v) for ethanol and 5-10% (v/v) for butanol

An Integrated Management System to reduce False Codling Moth, Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae) infested citrus fruit from being packed for export

False codling moth (FCM), Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae) is indigenous to southern Africa and is an important pest of citrus in this region. As a result of its endemism to sub-Saharan Africa, several countries to which South Africa exports citrus, regulate it as a phytosanitary pest. Consequently, it is necessary to ship fruit to these markets under cold-disinfestation protocols. This has been possible, as until recently, all of these markets could be considered relatively small niche markets. The South African citrus industry exports approximately 130 million cartons of fruit (15 kg equivalent) annually. During the 2017 season, a total of 48 million cartons were exported to the European Union (EU), which is the equivalent of 41% of South Africa’s total export volume, thus making the EU South Africa’s most important export market. In 2013 the European and Mediterranean Plant Protection Organisation (EPPO) conducted a pest risk analysis (PRA) on FCM, leading to the EU declaring it an officially regulated pest for this region, effective of 1 January 2018. Citrus is regarded as a preferred non-native host of FCM and South African citrus was identified as a primary focus due to large volumes being exported to Europe. Shipping under cold disinfestation is not possible with such large volumes of fruit. Additionally, several cultivars would suffer high levels of chilling injury under such conditions. In this study, an Integrated Management System was tested with pre- and postharvest controls to test the hypothesis that pre-harvest interventions resulted in lower post-harvest infection. Thirty orchards ranging from soft citrus cultivars such as Nule and Nova Mandarins, to Navel orange cultivars such as Newhall, Palmer and Late Navel and ending with Valencia cultivars such as Midknight and Delta, were identified for this study. This system relies on pre-harvest inspections such as FCM trap counts and fruit infestation on data trees in every orchard, with associated thresholds for action or continued compliance. Inspections were conducted on a weekly basis. There was a significant relationship between the moth catches and FCM infestation for the full monitoring period, using a two-week lag period for infestation. Inspections of harvested fruit were conducted at the packhouse to determine FCM infestation. This included inspection of the fruit on delivery to the packhouse, on the packing line, and a final fruit sample taken from the packed product and inspected for FCM. The highest levels of infestation were recorded on the Navel cultivars, thus confirming that Navels cultivars are a preferred host for FCM. Significant positive relationships were recorded between FCM infestation during the last 4 weeks before harvest and the level of infestation in the fruit delivered to the packhouse and between the fruit delivered to the packhouse and in the fruit packed in a carton for export. There was a substantial reduction in infestation between the fruit delivered to the packhouse and the fruit packed in a carton for export, with certain orchards recording as much as a 93% reduction in the fruit packed in a carton, which indicated that the packhouse could effectively identify and remove FCM infested fruit. The outcome of the study is that a holistic management approach minimizes the risk of FCM in citrus fruit destined for export and therefore mitigate the risk associated with FCM

Citrus Culture in the Lower Rio Grande Valley of Texas.

63 p

Effect of canopy position and non-detructive determination of rind biochemical properties of citrus fruit during postharvest non-chilling cold storage.

Doctor of Philosophy in Horticultural Science. University of KwaZulu-Natal, Pietermaritzburg, 2017.No abstract provided.This thesis is a compilation of manuscripts where each individual chapter is an independent article/manuscript introduced disjointedly

Studies on the evaluation of quality in the Granny Smith apple

Quality is a complex property and cannot be measured directly. As present grading systems for apples are not entirely satisfactory, there is a need to establish simple quantitative methods for estimating apple condition that are relevant to consumer perception of quality

North American Fauna 64

Examination of the body covering of the northern fur seal at each stage of growth as well as variations and anomalies

The Philippine journal of science.

v.20 (1922