English abstract
Of the commercially important agricultural commodities produced in Oman, dates, the fruit of the date palm Phoenix dactylifera are of particular importance. So, it is crucial to understand the phase transitions of dates in characterizing their quality and in designing efficient processing systems. Construction of the state diagram for dates will provide the freezing curve, solubility curve, eutectic point, glass transition line, and conditions of maximal freeze concentration (temperature and solid mass fraction) for our materials. This thesis distinguishes between the different mechanisms that determine the physical state of various ingredients in dates with reference to rubbery vitrification, and crystallization. Substantial understanding of the vitrification properties of high sugar/biopolymer systems has been achieved recently using the technique of small-deformation rotational dynamic oscillation. This thesis also deals with the freezing curves of bovine gelatin. This allows comparisons of the structural properties of dates and gelatin with the view of replacing each other in product formulations. The results of this thesis contribute towards the improvement of processed foodstuffs containing date ingredients. State diagrams guide us towards replacing conventional biopolymers in a number of product areas, including ice cream, confectioneries and jellies. These ideas should be taken up by the food industry for the development of appealing processed foodstuffs
