Técnicas de resfriamento de arroz cozido alteram a formação de amido resistente

Abstract

Rice (Oryza sativa L.) is a cereal of global importance, whose nutritional value is significantly affected by processing and cooking. RS, a non-digestible starch fraction with beneficial effects on metabolic and intestinal health, is mainly formed during the retrogradation of cooked and cooled starch and is influenced by intrinsic rice factors such as amylose concentration, fiber, lipids, and proteins, as well as extrinsic factors like cultivation conditions and added components during preparation, such as oils. This study investigated the modulation of resistant starch (RS) in rice, considering the influence of different genotypes, the type of oil used in preparation, and cooling methods. The methodology involved the characterization of rice genotypes (BRSEsmeralda, BRSMG Caçula, CMG1590, and commercial varieties) regarding amylose content, proximate composition of raw and prepared grains, as well as the quantification of phenolic compounds and antioxidant capacity. The rice preparation technique was standardized, altering the oil used for sautéing (avocado oil or soybean oil) and the cooling method (room temperature, refrigerator at 4°C for 24h, and freezer at -15°C for 24h). RS quantification was performed by a standardized enzymatic method (Association of Official Analytical - AOAC, 2002). It wasfound that amylose content is important, but the grain matrix, including fiber content, apparently modulates RS formation, sometimes overriding high amylose content. Post-cooking cooling resulted in significant increases in RS for most genotypes, except black rice, which showed a reduction (up to -22.36% with soybean oil in the freezer). The type of oil (avocado vs. soybean) showed a marginal impact on RS formation; however, avocado oil, with its superior nutritional profile, can add value to the meal without compromising RS. It is concluded that grain composition and cooling are determining factors in RS formation, offering practical strategies to optimize health benefits.