Impact of sugar replacement by non-centrifugal sugar on physicochemical, antioxidant and sensory properties of strawberry and kiwifruit functional jams

Raw cane sugars have been claimed to be rich in natural phenolic compounds which, in contrast to refined sugar, may increase the nutritional value of foods and contribute to the development of healthier foods and diets. The use of non-refined cane sugars in food formulation seems an interesting option since they provide natural antioxidants with sucrose still being the major sugar present, minimizing the loss of technological properties. However, substitution of refined sugar could imply an undesired impact on physicochemical and sensory properties, conditioning consumer's acceptance. Functional jams (strawberry and kiwifruit) with a larger fruit to sugar ratio than conventional ones, in which white sugar was replaced by granulated jaggery (0, 15, 30, 45, 60 y 75 % w/w) were obtained. Impact of sugar replacement was assessed by evaluating physicochemical properties (moisture, water activity, pH, total soluble sugars, sugar profile (glucose, fructose, sucrose), and optical, rheological, mechanical and antioxidant properties). Sensory properties and microbiological stability were also determined. Jaggery improved the antioxidant properties of jams (total phenolic content, total flavonoid content, antiradical activity by the DPPH and ABTS methods), proportionally to the amount of cane sugar incorporated and more significantly in the case of kiwifruit. Other physicochemical properties were not significantly affected by jaggery, except for color. However, these differences were not crucial in the acceptability tests, since acceptance of jams containing jaggery was generally good, very good when intermediate replacement percentages were used. Conclusions of the present work suggest that granulated jaggery can be used to formulate sugar-rich food products such as jams in order to increase their nutritional value, with little impact on physicochemical properties and good consumer acceptance.