Lycopene extraction from extruded products containing tomato skin

To determine the lycopene content of extruded products containing 10% tomato skin, the conditions for solvent extraction were optimised. After three extraction cycles at 50 °C each for 15 min at a solvent to meal ratio of 40:1, a maximum of 6.6 ppm lycopene was extracted. However, the extraction was considered incomplete, thus the product was digested by pancreatin prior to extraction. The extracted lycopene content was increased to 23.5 ppm using the optimum conditions of 20 min of digestion with 10 mg mL−1 pancreatin. To validate the extraction efficiency at optimum conditions, a set of extruded products containing different lycopene concentrations was used. Digestion increased the extracted lycopene content by more than 2.5-fold between the products. Furthermore, this inclusion significantly improved the correlation coefficient between the red colour and the extracted lycopene content. Therefore, including a digestion step prior to extraction by solvents was necessary to efficiently extract lycopene from extruded products

Lycopene bioaccessibility and starch digestibility for extruded snacks enriched with tomato derivatives

Nyanhanda, T ORCiD: 0000-0001-6502-5645To improve the nutritional value of energy-dense extruded snacks, corn grits were replaced with tomato paste and/or tomato skin powder at ratios of 5, 10, and 20% and extruded to make expanded snack foodlike products. Using a model digestion system, lycopene bioaccessibility and uptake from the snacks into Caco-2 cells were determined. The digestibility of the starch, the main nutrient component of the snacks, was also investigated. While extrusion cooking reduced the lycopene content of the snacks, the proportion of bioaccessible lycopene increased. Lycopene uptake by the Caco-2 cells from the extruded snacks exceeded that of the control in which the lycopene was not extruded, by 5% (p < 0.05). The digestibility of starch in the snacks varied depending on the type of tomato derivative and its concentration. Optimization of the extrusion cooking process and the ingredients can yield functional extruded snack products that contain bioavailable lycopene. © 2011 American Chemical Society

Effects of Xanthan Gum, Lambda-Carrageenan and Psyllium Husk on the Physical Characteristics and Glycaemic Potency of White Bread

White bread contains a high proportion of easily digestible starch, which contributes to an undesirable rapid increase in blood glucose concentration. This study investigated the effects of nonstarch polysaccharides (NSP) -xanthan gum, lambda-carrageenan and psyllium husk on the physical functionality and glycaemic potency of white bread. The amount of water for each formulation was adjusted based on DoughLab set at a target torque value of ~500 FU for sufficient dough development. Adding NSP generally resulted in significantly increased loaf volumes and decreased hardness. The glycaemic potency (glycaemic glucose equivalents (GGE) g) of bread was found to be reduced with the addition of NSP at all levels (1, 3 and 5% w/w based on flour weight). Increasing the concentration of xanthan gum and lambda-carrageenan did not show any further decrease in the glycaemic potency. Notably, adding 5% w/w psyllium husk significantly reduced the glycaemic potency from ~49 GGE/100 g in the reference bread to 32 GGE/100 g. The reduction in the glycaemic potency was attributed to viscosity effects (for xanthan) and starch–NSP interactions (for psyllium husk). Overall, the 5% w/w psyllium husk bread sample was most promising in terms of both physical characteristics and its effect on in vitro glucose release