Using different fibers to replace fat in sponge cakes: In vitro starch digestion and physico-structural studies.

This study assessed the effect of substituting 30% of fat by soluble, insoluble fiber, or a mix of both fibers in sponge cake quality, structure, acceptability, and starch digestibility. The apparent viscosity of the different formulations was measured and micro-baking was simulated. Texture profile tests were carried out and the crumb structure was examined. In vitro digestion was performed to study the digestibility of starch and a sensory test was carried out to know consumer acceptance. The soluble fiber (maltodextrin) affected the structure and quality of the cakes less than the insoluble fiber (potato fiber) and the use of soluble fiber in the formulation resulted in lower glucose release under in vitro conditions. Moreover, the consumer did not find differences among the control cake and the cakes prepared with soluble fiber. Considering the results as a whole, soluble fiber may be used for partial replacement of fat in sponge cake formulations and may constitute an appropriate strategy for obtaining healthy sponge cakes.

Effect of CO2 deastringency treatment on flesh disorders induced by mechanical damage in persimmon. Biochemical and microstructural studies.

Manifestation of flesh browning while commercialising 'Rojo Brillante' persimmon is one of the main causes of postharvest loss. It is known that mechanical damage is a decisive factor for browning development and that astringent fruit is less sensitive to this disorder than fruit submitted to a CO2 deastringency treatment under standard conditions (24h, 95% CO2, 20 °C). However, there is no information available about the mechanism behind this alteration. In the present study, we evaluated the effect of treatment with high CO2 concentrations applied for 0-40 h on the incidence of mechanical impact-induced flesh disorders using biochemical, chromatographic and microstructural techniques. Our results show that the longer the CO2 exposure, the higher the incidence and the greater the severity browning. A deastringency treatment with CO2 results in O2(-) accumulation in fruit, which is greater the longer treatment is. However, mechanical damage triggers the browning manifestation, resulting in the accumulation of both O2(-) and H2O2. In this oxidative stress state, which must be greater as higher the level of O2(-) previously accumulated in the deastringency treatment, insoluble tannins initially uncolour, undergo an oxidation process and turn red-brown, observed as flesh browning. Moreover, we identified a new disorder, "pinkish-bruising", which is manifested in astringent fruit. The mechanism of this alteration, also associated with mechanical damage, seems similar to that of browning, but the oxidation process would affect soluble tannins.