An adequate diet and lifestyle can have an important role in delay the onset of chronic degenerative disease (Miller et all., 2003). In particular, observational studies have shown that the glycemic index (Gi), indicator of the ability of carbohydrates to increase the level of glucose in blood (Glycemia), is directly correlated with the risk to develop diabetes mellitus type 2 and cardiovascular diseases (Salmeron et all., 1997a, 1997b; Liu et all., 2000; Livesey et all., 2013).
Food as sugar and potato refined starch have an high glycemic index: this means that they increase the glucose level in the blood after the meals. On the contrary, food like lentils, beans, soya, have a low glycemic index and a reduced negative impact on the glucose concentration in the blood after meals; as well as whole food, that have a lower glycemic index than refined food at more rapid absorption, and seem to be more indicated for controlling the post-prandial glycemic values (Bland and Benum, 1999). Therefore, food with a low glycemic index may be considered as a class of functional food that has a positive effect against both diabetes mellitus type 2 and coronary diseases. In this perspective in recent years the attention has focused on how some functional food may influence the glycemic response both in healthy subject and subject at risk.
Reduce the glycemic index
Food industry has experienced different technologies to reduce Gi of some food. In this regard, it is worth to mention the beta-glucans and/o other fibers addition to food products and even the partial substitution of glucose (Gi 84%) with fructose (Gi 29%). This shows that by acting on the amount of one or more ingredients, it’s possible to realize a functional food that has beneficial characteristic on glucose and insulin metabolism and, in the same time, with a palatability such that they can be consumed in the diet every day. An additional strategy to reduce Gi of food is to use technologies able to modify the digestibility of starch. This is the case, for example, of the parboiled rice. This technology consists in submitting grains of rice to an high pressure steam treatment such to form an outer layer of retrograded starch. This latter is better known as resistant starch, because it resists to the hydrolyses of the amylase of human gut. Therefore, retrograded starch has a lower capacity to increase the blood glycemic values and so is able to decrease the food Gi.
The pasta, popular food for its ease of use and for its nutritional properties, shows an important health aspect, a glycemic index lower than white bread because of its slowly digestible starch (Jenkins et al., 1981; Monge et al., 1990). The pasta low glycemic index can be explained by many macroscopic and not macroscopic factors, like size – vermicelli vs spaghetti -, and shape – maccheroni vs spaghetti- (Colonna et al., 1990; Wolve et al., 1986); the encapsulation of starch granules in the gluten network (Colonna et al., 1990; Fardet et al., 1998); fibre content (Tudorica et al., 2002); the physical structure of the starch, as its degree of gelatinization (Duszkiewicz-Reinhard et al., 1998) and its retrogradation (Akerberg et al., 1998); the amylose and amylopectin ratio (Duszkiewicz-Reinhard et al., 1998; Akerberg et al., 1998). The modification of one or more of these structural elements with the addition of fiber or raw materials with a physical structure of starch that is different from that of wheat could induce a change of pasta glycemic index.