A study was made of the texture, composition, appearance, colour and descriptive sensory analysis of low-fat chocolate muffins in which part of the oil ingredient (25%, 50% and 75%) had been replaced by soluble cocoa fibre and full-fat (no fat replacement) control sample to which cocoa powder had been added for comparison purposes. The rheology of the batter was studied with a rheometer. The height of the baked product fell as the fat replacement percentage rose, but no weight loss differences were observed after 1-h cooling. The texture of the fat replacement muffins showed lower values for hardness, chewiness and resilience than those of the control sample and retained greater moisture. The chocolate colour of samples with the highest level of fat replacement was scored similar to the full-fat control formulation indicating a good colour development without adding cocoa powder. The sponginess and springiness of the samples with the lowest fat replacement were scored similar to the full-fat control formulation. In general, muffins containing cocoa fibre were increasingly more cohesive and more difficult to chew and swallow when higher level of cocoa fibre was added. A certain degree of stickiness and a bitter taste different from that of cocoa were found.

A study of refrigerated storage (10 degrees C for 91 d) of whole and skimmed flavored set-type yogurt was made. Comparison with storage at 20 degrees C for 21 d and 30 degrees C for 3 d (accelerated) was also carried out. Refrigerated storage yogurts were assessed by a trained panel and by a consumer panel. Trained-panel scores were correlated to instrumental data, and the acceptability data for long storage were studied using consumer criteria. In all cases, after-storage pH values barely changed over storage time, indicating that the yogurt samples did not develop much acidity under any of the storage conditions studied. The profile of the instrumental texture curves obtained corresponded to a firm gel, which broke after a plunger penetrated the sample, and the firmness values of the whole yogurt were lower than for the skimmed yogurt under all the storage conditions studied. From a microbiological point of view, the viability of the yogurts was adequate at the different storage times and temperatures studied, although those stored at 10 degrees C for long periods would not comply with some countries' minimum requirements. Logistic regression of the data from a 50-consumer sensory evaluation showed that the probability of the whole yogurt being accepted after 91 d storage at 10 degrees C was around 40%, whereas for the skimmed yogurt it was only 15%, largely because the skimmed yogurt developed certain negative attributes at an earlier stage of storage than the whole yogurt.

The effect of replacing part of the wheat flour with a resistant starch rich ingredient (RSRI) − a source of functional fibre with potential health benefits − was studied in short dough biscuits. A control with no replacement and 3 formulations in which 20, 40 and 60g of flour per 100 g were replaced by an RSRI (samples 20RSRI, 40RSRI and 60RSRI) were prepared. From a technological point of view, the RSRI level influenced the consistency of the raw dough and the ease of sheeting and cutting. Regarding the eating quality of the final product, addition of the RSRI increased the breaking strength and crumbliness and reduced the resistance to penetration. In the RSRI biscuits, both the surface and the crumb were paler. The sensory acceptance of the 20RSRI biscuits did not differ significantly from that of the control. 40RSRI reduced the acceptability of the colour, appearance and texture without altering the taste, sweetness and overall acceptance. Neither of these two levels significantly reduced the consumption intention. However, 60% flour replacement produced biscuits with lower sensory acceptability and a significant reduction in consumption intention. In general, the results could be interpreted in terms of the protein-diluting effect of the added ingredient and changes in the water content and water-retention capacity of flour mixtures containing RSRI. The present results proved that resistant starch rich ingredients (RSRI) have good potential for developing fibre-rich biscuits without changing their general features.