Dados do Trabalho

Título

MODIFICATION OF RICE AND BEAN STARCH BY PRE-GELATINIZATION AND ULTRASOUND: IMPACT ON IN VITRO DIGESTIBILITY

Introdução

Starch modification aims to achieve functional properties not found in its natural state, thereby expanding its applications. Ultrasound generates cavitation bubbles in the liquid medium, which can alter the properties of starch, which is promising for the food industry as it allows the obtaining of starches with differentiated characteristics cleanly and efficiently. This study aimed to analyze the in vitro digestibility of native and pre-gelatinized rice and carioca bean starch, as well as their fractions of rapidly digestible, slowly digestible, and resistant starch.

Material e Métodos

Native starches were gelatinized in a water bath for 30 minutes and subjected to ultrasound for another 30 minutes at 25°C, precipitated with 50% ethanol, and dried in an oven with air circulation at 40°C for 24 hours. For in vitro digestibility, the starches were re-gelatinized as a gel at a concentration of 4%. Gastric phase (30 minutes) and intestinal phase (120 minutes) digestion were simulated using pepsin enzymes in the gastric phase and invertase, pancreatin, and amyloglucosidase in the intestinal phase.

Resultados e Discussão

. After pre-gelatinization, the starches exhibited different hydrolysis behaviors. After 120 minutes of digestion, 86.68% and 88.00% hydrolysis were observed in pre-gelatinized bean and rice starches, respectively, while their respective native starches already exhibited over 90% hydrolysis after 60 minutes of digestion. In addition to the final reduction in digestion at 120 minutes, it was also possible to observe that pre-gelatinized starches presented a slower and more controlled glucose release rate. Slower digestion can promote a feeling of satiety for longer when starches are applied in food formulations. Pre-gelatinized starches presented a higher resistant starch content (25.98-26.24%, p<0.05) compared to their native counterparts (16.27-18.67%) for rice and bean starches, respectively.

Conclusão

The results indicate that the use of techniques such as pre-gelatinization and ultrasound can be an effective strategy to develop modified starches with reduced digestibility and high resistant starch content, which can expand the range of applications in the food industry, especially in the production of low-glycemic index foods.