Abstract:
Jams and marmalades are some of the most popular fruit products because of their low cost, all year long availability and appealing sensory properties. These products are described as gels with pectin as the gelling agent used in its formulation. Gels are a form of matter intermediate between a solid and liquid consisting of polymeric molecules cross-linked to form tangles. Under mechanical stress, pectin gels may be damaged leading to the release of colloidal water termed as syneresis. This study was aimed at solving the challenge of syneresis by integrating pectin with other hydrocolloids such as gum arabic. Gum arabic from Acacia senegal var. Kerensis was added in the range of 1-5% as an additive in the fruit spreads. Different fruits were used to make the jam (red Plums and Pineapples) and marmalade (Orange and Lemon) with gum Arabic (1%, 2%, 3%, 4% and 5%). Jam and marmalade without any gum Arabic was also prepared as a control in the study. Proximate composition and Microbial analysis were carried out using approved AOAC methods whereas sensory evaluation was carried out using a semi trained panel. Viscosity analysis was done using the Brookfield Viscometer. Syneresis was measured using centrifugation method. Results for microbial indicated that the product was safe for consumption having no growths for TVC, TCC and yeast and moulds. The attributes included taste, texture, spreadability, aroma, flavour, colour and general acceptability. Red plum jam and Pineapple jam had its best performance for spreadability at 5% and 4% gum arabic, respectively. The jams at 5% gum arabic performed best in terms of the general acceptability. Lemon marmalade had best performance for general acceptability at 4% level of gum arabic. From the study, gum arabic has no significant impact at p<0.05 level of significance on the microbial quality as well as the proximate composition of the formulated jam and marmalade. Viscosity tests were performed on the jam and marmalade with results indicating shear thinning for the formulated products. From this study, gum Arabic which was meant to reduce the level of syneresis played a role on the texture as well as viscosity of the product as the concentrations of gum changed. This is the first report on preparations of jams and marmalades with reduced syneresis due to the utilisation of gum arabic from Acacia senegal var. Kerensis.
