Glycemic Index Analysis of Functional Bakery Products on a Group of Healthy Volunteers, a NUTRACORE Study

For these reasons, in recent years the food industry has tried, not always successfully, to experiment with alternative formulations for its products, implementing a series of techniques to reduce the GI of foods, in particular those based on cereal flour. There are different methods useful to reduce the GI; in particular, the most impacting aspects of the GI of food containing carbohydrates are the sugar content, the starch content, the type of starch, the cooking method, previous processing, pre-cooking, post-cooking cooling, soaking, particle size and fiber quantity.

Increased consumption of soluble fiber is associated with reduced absorption of sugars in the intestine and therefore a reduced GI. On the contrary, most of the fibers contained in cereals and tubers are not soluble. For this reason, the direct effect of fibers on glycemic absorption is not significant. On the other hand, whole grains generally have a lower glycemic index than refined grains and this may be due to a combination of factors such as reduced digestibility, higher starch-content resistance, and the effects of other constituents of bran (such as lipids). Insoluble fibers are also attributed to a greater satiating effect.

The determination of the glycemic index can be estimated in vitro with good accuracy through an artificial digestive apparatus, or dynamic gastric model (DGM) but the gold standard remains the analysis of the glycemic response on subjects in vivo, typically volunteers. The ISO standard 26642 guidelines of 2010 represent the gold standard for the analysis of GI in humans and consists of a few simple steps that require blood sampling to determine blood sugar at the time 0, 15, 30, 45, 60, 90, and 120 min. The GI is but the average of the proportions between the sum of the 7 areas created by placing time on the abscissa (in minutes) and the ordinate blood sugar levels at each T (expressed in mmol/L or mg/dl) after consuming the test food compared to the sum of the areas created after consuming the reference food, usually glucose.

Secondly, the modulation of the intake of sugars and calories can also be managed through alternative methods. It has been seen that, for example, different stimuli related to the sense of taste can modulate the sense of hunger and consequently the calorie intake in the following hours. This is especially true with the bitter taste. Appetite modulation due to the administration of particular foods was primarily associated with particular polymorphisms of receptor genes associated particularly with a bitter taste (TAS2R) and sweet (T1R2-T1R3). At the same time, the discovery of extra-oral receptors to recognize bitterness (extra-oral TAS2R) led the researchers to test the effects of administering particular bitter foods without the potential confounding effect of oral ingestion.

Among recent studies, some researchers have shown that the effect of reducing energy intake has not been statistically significant in a group of overweight women, at least for some types of encapsulated bitterness while others have proven that an intragastric infusion of bitters significantly reduced hunger in a group of normal-weight women. Another study, in the short term, showed instead that an administration of bitters encapsulated with the base of 'Gentiana Lutea' during the morning meal can significantly reduce the energy intake of the day.