https://www.um.edu.mt/library/oar/handle/123456789/10661 Thu, 09 Apr 2026 06:08:42 GMT 2026-04-09T06:08:42Z https://www.um.edu.mt/library/oar/handle/123456789/92913 Title: Metal sorption isotherms of agricultural calcareous soils from Malta Abstract: The scope of this dissertation was to analyse how a better understanding of metal sorption isotherms in agricultural calcareous soils in the local scenario can help boost and maintain soil fertility. The question this study sought to answer is whether there is a relation between the extent of solutes adsorped when comparing diverse metals at different concentrations and whether the level of metal adsorption differs from one soil sample and another. It also required a detailed analysis on the differences in the predicted and obtained results for the sorption affinity of the samples tested. This was carried out by investigating the amount of metals studied (Copper (Cu), Lead (Pb) and Zinc (Zn)) that were attached to different types of soil as a function of solute concentration and analysing the extent of adsorption of each specific metal in the soil samples tested. Solutions of each individual metals at concentrations of 0, 10, 50, 100, 250, 500 and 1 OOOµM were analysed. These were derived using the MP-AES. From the values obtained, the adsorption affinity of each individual metal was established. From the results obtained, it was found that all samples tested demonstrated a high affinity in adsorption for all the three metal cations observed. Pb had a relatively slightly higher but similar affinity when compared with Cu. Zn, on the other hand, had a slightly lower adsorption capability at higher concentrations. From the texture analysis data, a high adsorption affinity was expected in the soil having more clay. However the adsorption affinity values were similar in the two soil types used. This outcome could be the effect of a high soil organic matter (SOM) content. All these results will help give a more profound understanding of the local soil properties and will help move towards more ecologically aware agricultural practices, particularly when considering the amounts of metal applied with fertiliser in the fields. Description: B.SC.(HONS)MED.AGRO-ECO.MANGT. Wed, 01 Jan 2014 00:00:00 GMT https://www.um.edu.mt/library/oar/handle/123456789/92913 2014-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/92511 Title: The moisture, total polyphenolic, anthocyanins and hydroxymethylfurfural contents of experimental jams produced from locally-grown strawberries Abstract: The aim of this dissertation was to analyse four parameters in home-made and laboratory experimental jams produced from locally-grown strawberries. These were also analysed in the fruit samples themselves and four commercial jams selected at random. These parameters include: Moisture, Total Polyphenolic, Anthocyanins and Hydroxymethylfurfural Contents. For this to be achieved, several test methods were carried out. Moisture content was analysed by oven-drying, where the difference in weight from fresh to dry weight samples corresponded to the water loss. The Folin-Ciocalteu microtitre plate method was followed as the test for total polyphenolic content, with a 750 nm wavelength for absorbance. The pH differential method was followed as the test for anthocyanin content, with absorbance at 496 nm, while the test followed for hydroxymethylfurfural was the rapid testing, using strips, for determning the individual values once absorbance values were obtained at 420 nm wavelength. The results obtained were tabulated in the form of tables from which graphs were constructed to follow trends for comparisons. Basically the moisture content declined where jam preparations with the addition of lemon juice were generally highly significantly different from those that had no additions. The total polyphenolic content increased overall with time. There was a significant difference between the strawberries and the 0-minute interval for most strawberry treatment combinations, and also a significant difference during the entire heating process up to 40-minutes. The commercial jams exhibited a total polyphenolic content lower than the laboratory and home-made experimental jams, mainly due to different processing treatment and different shelf lives. Anthocyanin content decreased at 0-minute due to degradation by heating, and at 40-minute they were transformed into more complex condensed tannins. The anthocyanin content of different commercial jams was statistically significantly different for each, and a significant statistical difference was present when compared to experimental jams. Hydroxymethylfurfural increased slightly with time, which is an indicator of degradation. There was a highly significant difference in hydroxymethylfurfural content for experimental jams to commercial jams, where the content mostly depends on temperature limit during processing and the heat treatment applied during processing. Description: B.SC.(HONS)MED.AGRO-ECO.MANGT. Wed, 01 Jan 2014 00:00:00 GMT https://www.um.edu.mt/library/oar/handle/123456789/92511 2014-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/92496 Title: The performance of vegetable transplants using two irrigation systems in nurseries Abstract: Irrigation plays an important role in the quality of plug plant production in crop nurseries. This study was carried out in order to evaluate the effects that different irrigation methods have on the growth and development of plant plugs of various crops. Two different irrigation methods were used in order to investigate and hence, compare the differences in growth and development of different vegetable crops. The irrigation methods that were used are the overhead irrigation and the sub-irrigation. Five different vegetable crops were chosen for the experiments, namely tomatoes, lettuce, cauliflower, peppers and melon, so that a wide range of results could be obtained for comparison purposes. The experimentations were initiated and terminated on the same days and were held in a greenhouse nursery, providing the same climatic conditions for all crops. Also, length and weight measurements were always taken and recorded at the same time, to obtain fair results. This research shows that there was a significant difference between the plug plants watered by sub-irrigation and those watered by overhead irrigation. This resulted in all crops, except the peppers. Sub-irrigation proved to grow the plants in a shorter time span and still having good quality. Moreover, root to stem ratio in sub-irrigation was more uniform that that of the overhead irrigation. Therefore, results obtained from this research indicate that plug plant producers would benefit more when using the sub-irrigation method to water their plants. This is due to the fact that transplant size is achieved before, thus less resources are used on the plants. Description: B.SC.(HONS)MED.AGRO-ECO.MANGT. Wed, 01 Jan 2014 00:00:00 GMT https://www.um.edu.mt/library/oar/handle/123456789/92496 2014-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/92481 Title: The physicochemical, polyphenol, antioxidant and antibacterial properties of Maltese honey Abstract: Since ancient times, Maltese honey has been highly prized for its aromatic flavour and medicinal properties, so much so that Malta was commonly nicknamed as "the land of honey". Apart from its flavour, nutritional and calorific value, honey has a long legacy of use in traditional medicine and a strong backing from modern scientific research. Despite its fine medicinal reputation, no coherent studies on the antimicrobial properties of Maltese honey have yet been published. The objective of this study was to give a first insight on the antibacterial properties of Maltese honey and present a point of departure for potential future production of medical grade honey of local origin. Honey samples (n=12) of varying type (monofloral and multifloral), floral origin, harvesting season and location were randomly collected to provide an elementary representation of Maltese honey. The antibacterial analysis was complimented with physicochemical, total polyphenol and antioxidant activity determination. Antimicrobial activity was investigated using the broth macro-dilution method (CLSI, 2012). The mean minimum inhibitory concentrations (MIC) on three bacteria; Escherichia co/i ATCC® 25922, Staphylococcus aureus ATCC® 259213 and Pseudomonas aeruginosa ATCC® 27853, were found to 0.18 g/ml ± 0.07, 0.12 g/ml ± 0.05 and 0.15 g/ml ± 0.06 respectively and MIC values ranged 0.031 to 0.25 g/ml. Statistical analyses revealed that there is a significant difference between spring and autumn honey derived from difference in free acidity, total polyphenols, colour, HMF content, conductivity, DPPH antioxidant strength and antibacterial properties against 5. aureus. There was no statistical difference between seasons in the other parameters tested. Antimicrobial properties against 5. aureus correlated with colour, total phenolic content and antioxidant strength while MIC results for P. aeuroginosa correlated with total phenolic content. Maltese honey is high in total phenolic content, has antioxidant properties and is a good antibacterial agent. Thus, such results signify that more research is required to determine the source of antimicrobial strength in specific types of Maltese honey. Description: B.SC.(HONS)MED.AGRO-ECO.MANGT. Wed, 01 Jan 2014 00:00:00 GMT https://www.um.edu.mt/library/oar/handle/123456789/92481 2014-01-01T00:00:00Z