The effect of hydrodynamic conditions on the monogastric-like in vitro digestion of maize flours dried at different temperatures

Digestion of curcumin-fortified yogurt in short/long gastric residence times using a near-real dynamic in vitro human stomach

A dynamic in vitro human stomach (DIVHS), simulating the anatomical structures, peristalsis, and biochemical environments of a real stomach as practically as possible, was applied to mimic the gastric pH and emptying during yogurt digestion in short/long gastric residence times. The influences of peristalsis, dilution, and proteolysis on digesta viscosity were quantified respectively, indicating the dominant role of proteolysis and dilution. After incorporating curcumin-whey protein microparticles with targeted-release formula in yogurt, the peak curcumin release during intestinal digestion reached 43% at 120 min in the short gastric residence time and 16% at 180 min in the long gastric residence time. The change in the maximum curcumin release depended on the gastric emptying kinetics in each residence time. This emptying-kinetics dependence was reflected by the slower microparticle disintegration and proteolysis in the long gastric residence time. The dynamic reproduction of realistic gastric conditions using DIVHS helps revealing controlled release from foods.

The drying temperature and the moisture content at harvest affect the apparent metabolisable energy of two maize varieties in broiler chickens

1. The grain drying process may affect the feeding value of maize but until now, no general consensus has been reached. This knowledge is essential to manage maize nutritional value in feed and ensure optimal growth performance of broiler chickens. 2. A total of 72 male Ross 308 were used in a complete randomised block design to assess the effect of initial moisture content (MC) at harvest (high or low MC after the appearance of the black layer) and drying temperature (54°C, 90°C or 125°C) on the apparent faecal digestibility and the AMEn value of two maize grain types (flint and flint-dent varieties). Moreover, the relationship between in vitro dry matter digestibility coefficient (IVDMD) and salt-soluble protein (SSP) content of dried maize grain with AMEn was assessed. 3. High drying temperature (125°C) significantly decreased the AMEn (by 0.41 MJ/kg) of the maize. Maize with high-moisture content at harvest had significantly higher AMEn than maize with low moisture content (0.38 MJ/kg) depending on the variety. Based on the combination of MC at harvest and drying temperature, an AMEn difference of about 0.65 MJ per kg of dry matter was measured during this experiment. The faecal digestibility of starch remained close to 98% with low variation between the treatments. The decrease in AMEn at high drying temperature was related to the decrease in non-starch organic matter retention (NSOM_R). IVDMD and SSP content were not correlated with AMEn of dried maize (R² < 0.1). 4. This study showed that using drying temperature below 90°C for maize grain harvested at high MC, just after the black layer development, can enhance its AMEn. The IVDMD and SSP content failed to predict the AMEn of the dried maize, but further research is required to validate the results of this study.