No abstract

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.

Sayer date fruits were stored by different preservation techniques including high carbon dioxide modified atmosphere packaging (MAP), cool storage and freezing for 150 days. The effects of these treatments on several quality factors of the fruits were investigated. Control package samples (kept at 30C without atmosphere modification) had the highest number of live insects as well as yeast and mold colony counts (P < 0.05). pH values of the MAP samples stored at 30C were less than the other treatments. Water activity was reduced during the storage in all the samples. Fruit blemishing in the high CO2 MAP samples was similar to that of the controls. However, the least blemishing was at−18C. The MAP containing 85% CO2 + 3% O2 + 12% N2 and 75% CO2 + 12% O2 were chosen as the best methods of preservation and quality maintenance of sayer dates with limited effects on the appearance of physiological disorder signs. PRACTICAL APPLICATIONS The effect of different preservation techniques (high CO2 modified atmosphere packaging [MPA], cool storage and freezing) on insect elimination and quality of sayer date fruits was investigated. As no off‐odor or off‐flavor due to anaerobiosis was reported during the experiments, sayer dates were considered to be resistant to high CO2 concentration or low oxygen probably due to their low respiration rate. Both MPA containing 85% CO2 and freezing eliminated insects, inhibited mold growth, reduced sugar accumulation and produced negligible blemishing and pH reduction, and therefore were considered appropriate for preservation of sayer dates.

To 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.

Nutritionally enhanced extruded snack foods enriched with tomato paste powder were produced that contained lycopene and fiber. To simultaneously measure the in vitro bioavailability of lycopene and starch from the snacks, a digestion model was developed by using various concentrations of bile (0 to 20 mg/ml) and pancreatin (0, 0.4, 2.4, 4.8, and 6 mg/ml). In vitro bioavailability of starch was determined based on the glucose released and, for lycopene, the amount transferred to the micellar phase of digesta. Furthermore, the digestion was monitored by measuring the proportion of solids remaining at the end of digestion. The amount of glucose released from the starch after 120 min of digestion varied between 683 and 885 mg/ g starch at different bile and pancreatin concentrations. The presence of bile reduced the amount of pancreatin needed to maximize starch digestibility. The proportion of micellar lycopene increased from 5% to 43% with increases in both bile and pancreatin concentrations. At constant pancreatin concentration, increases in bile concentration enhanced the in vitro bioavailability of lycopene by up to fivefold, while at constant bile concentration, 1.5-fold increase was observed with the increases in pancreatin used. The proportion of solids remaining at the end of digestion varied from 14% to 70%. Increasing the bile and pancreatin concentration enhanced the digestion of the snack. In conclusion, the maximum amount of potentially bioavailable starch and lycopene in this study was obtained by using 4.8 mg/ml pancreatin and 10 mg/ml bile. Furthermore, the results suggest that bile and pancreatin collaborated in the digestion of both starch and lycopene present in the enriched snack.