Masters Degrees (Animal Sciences)
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Browsing Masters Degrees (Animal Sciences) by Author "Badenhorst, Ruben"
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- ItemQuantification and differentiation of egg quality as affected by hen age and storage time, with the aid of near infrared hyperspectral imaging(Stellenbosch : Stellenbosch University, 2021-04) Badenhorst, Ruben; Pieterse, Elsje; Colling, Janine; Stellenbosch University. Faculty of AgriSciences. Dept. of Animal Sciences.ENGLISH ABSTRACT: The aim of the study was to investigate the effect of hen age and egg storage time on certain internal, external and proximate egg quality parameters. Additionally, near infrared (NIR) hyperspectral imaging was used, in combination with multivariate data analysis, for the differentiation and quantification of egg quality as influenced by hen age as well as storage time. Amberlink hen eggs (n = 480) were collected from eight different age groups, which included ages 21, 29, 37, 45, 53, 61, 69 and 77 weeks. Each age group consisted of 60 eggs, which was further divided into six groups with 10 eggs per group, representing six different storage intervals. Storage days included 0 (day eggs were laid and collected), 15, 30, 45, 60 and 90 days where temperature was kept at roughly 15˚C and humidity at 75%. Eggs were first subjected to hyperspectral imaging, followed by physical quality analysis as well as proximate analysis, on the given storage days, to assess several egg quality parameters. The objectives for this study included: (i) to establish the effect of hen age on egg quality parameters; (ii) to study the effect of hen age and increased storage time on egg quality parameters and (iii) to investigate the application of NIR hyperspectral imaging for differentiation as well as quantification of hen egg quality. Hen age had a significant impact on the majority of the internal, external and proximate quality parameters. The most pronounced differences in egg quality parameters were observed in eggs collected from hens between the ages of 21 and 29 weeks. A significant interaction (hen age × storage time) for a few quality parameters were observed, while the rest of the parameters were either influenced by the main effect (storage time) or not affected. Eminent changes already occurred within the first 15 days of storage for the majority of the parameters. Near infrared hyperspectralimages for all eggs were acquired with a HySpex SWIR-384 pushbroom imaging system in the 400 – 2500 nm spectral range. Principal component analysis (PCA) could accurately separate eggs laid by different aged hens and stored for different time periods, and the trends observed correspond to differences in the proximate content. Subsequently, partial least squares regression (PLSR) was applied to the full dataset to construct quantitative prediction models for the Haugh unit (HU), protein, lipid and moisture content. Several optimization steps were implemented to test if the prediction models improved. This included, comparing the use of whole egg spectra with a smaller region of interest and a reduction in the wavelength. All constructed models showed reasonable accuracies, however refinement of the models is still needed. Overall the results indicated that hen age and storage time are two highly influential factors, which need to be considered when assessing egg quality. Hyperspectral imaging could also be used as a rapid, non-destructive screening technique for the successful differentiation and quantification of egg quality.