Impact of sugar and fat reduction strategies on the sensory and quality properties of bakery products

Abstract

Consumption of foods and beverages rich in sugar and fat negatively impacts on human health. The primary objective of this thesis was to examine different strategies for the reduction of sugar and fat in Chocolate brownies, Sponge cake and Shortbread biscuits assessed using sensory (hedonic & intensity) and physicochemical analysis indicators. A survey on attitudes towards the use of sugar replacers indicated consumer caution regarding the use of artificial sugar replacers. Therefore, a clean-label approach was adapted when formulating sugar reduction strategies. Sugar particle size manipulation was examined as a potential sugar and fat reduction strategy. Commercial brown (200- 5181µm) and white (102-378µm) sugar were separated into different size fractions by grinding and sieving. Chocolate brownies (CB) and Shortbread biscuits (SB) containing various sugar size treatments were formulated. Sensory analysis indicated that for SB, samples containing the coarser white sugar fraction (228-377µm) were perceived as the sweetest (p<0.05) and had higher scores for flavour liking (p<0.05) and overall acceptability (OA) (p<0.05). For CB, samples containing the smallest brown sugar fraction (459-972 µm) were perceived as the sweetest samples (p<0.05) and had the highest perceived moisture (p<0.05) and soft (p<0.05) texture. Fat perception in foods is strongly related to texture and mouthfeel, therefore sugar particle size reduction may also facilitate fat reduction. Natural fat (pureed black beans (PBLB)) and sugar replacers (inulin and steviol glycosides) were examined in brownie formulations to determine the minimum levels of fat and sugar necessary for sensory acceptance. The smallest sugar fraction (459-972µm) permitted a higher level of fat replacement (75%) using PBLB as a fat replacer. Inulin and rebaudioside A replacing sucrose is feasible at 25% in fat-replaced (75%) brownies prepared with small sugar particles. Utilising the same sugar replacers, a minimum level of sugar and fat required for sensory acceptance of Sponge cakes was determined using pureed butter beans (PBRB) as a fat replacer. PBRB replacing fat is feasible at 50% in sucrose-replaced (30%) cakes using inulin and rebaudioside A. Finally, optimised sugar and fat-reduced products (OSFR) (Chocolate brownie and Sponge cake) were compared to products commercially available on the Irish market and preference of OSFR samples was observed.