Evaluation of the Glycemic Response to a Pasta Enriched With Carob Flour: a Study Conducted in Healthy Subjects and a Study Conducted in Subjects With Type 1 Diabetes Mellitus

Carob (Ceratonia siliqua) is a fruit traditionally used in various Mediterranean countries for the preparation of sweets and beverages. Its pulp, once the seeds are removed, is milled into carob flour, a nutrient-rich food containing fiber, carbohydrates, proteins, and essential minerals such as potassium, magnesium, sodium, phosphorus, and calcium. Carob flour is also naturally sweet and can serve as a cocoa powder substitute in desserts. Furthermore, it is a source of polyphenols with known antioxidant properties.

Clinical evidence suggests that consumption of foods rich in refined carbohydrates is associated with elevated postprandial blood glucose levels, which are recognized as an independent cardiovascular risk factor. The glycemic index (GI) is a useful parameter to assess the impact of carbohydrate-containing foods on postprandial glycemic response. Based on carbohydrate quality, foods are classified as having high, medium, or low GI. Consumption of high-GI foods leads to a stronger glycemic response and has been linked to increased risk of chronic conditions such as type 2 diabetes, obesity, and cardiovascular disease.

Given its bromatological profile, carob flour may have the potential to modulate postprandial glycemic responses. However, studies evaluating the GI of carob-based products have shown inconsistent findings. In one randomized trial involving 10 healthy adults, a carob-based snack demonstrated a lower GI (40) compared to a chocolate cookie with an equivalent carbohydrate content (GI 78), using glucose as the reference. The same study found that consuming the carob snack before a meal led to a reduced postprandial glycemic response, decreased hunger, and lower caloric intake at an ad libitum meal. Another study on 7 healthy individuals reported a GI of 39 for carob flour bars containing 26 g of available carbohydrates. Conversely, a study involving 20 healthy participants found that consuming 5 or 10 g of carob pulp with 200 mL of water and 50 g glucose increased postprandial glycemic and insulinemic responses compared to water and glucose alone. This effect was not observed with a 20 g dose of carob pulp.

Among carbohydrate-rich foods, pasta represents a key component of the Italian diet and, due to its physical structure, generally has a low-to-moderate GI. Compared to other wheat-based foods like bread, pasta tends to produce a lower postprandial glycemic response when carbohydrate content is matched. However, the impact of adding carob flour to durum wheat semolina in pasta production on postprandial glycemia remains unexplored.

The current research project consists of two studies. The first study aims to determine the glycemic index of carob-enriched durum wheat pasta in healthy adult volunteers, using white bread as the reference food. The second study investigates the postprandial glycemic response to the same carob-enriched pasta in individuals with type 1 diabetes, comparing it to traditional durum wheat pasta. These studies are designed to contribute to the understanding of carob flour's role in glycemic control, with potential implications for dietary management in both healthy individuals and patients with diabetes.