Please use this identifier to cite or link to this item: 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
Authors: Spiteri, Jessica (2014)
Keywords: Jam -- Malta
Strawberries -- Malta
Polyphenols
Anthocyanins
Flavonoids
Issue Date: 2014
Citation: Spiteri, J. (2014). The moisture, total polyphenolic, anthocyanins and hydroxymethylfurfural contents of experimental jams produced from locally-grown strawberries (Bachelor’s dissertation).
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.
URI: https://www.um.edu.mt/library/oar/handle/123456789/92511
Appears in Collections:Dissertations - InsES - 2014
Dissertations - InsESRSF - 2014-2015

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