A carregar...
Projeto de investigação
Not Available
Financiador
Autores
Publicações
Rice Bran Stabilisation and Oil Extraction Using the Microwave-Assisted Method and Its Effects on GABA and Gamma-Oryzanol Compounds
Publication . Reis, Núria; Castanho, Ana; Lageiro, Manuela; Pereira, Cristiana; Brites, Carla Moita; Vaz-Velho, Manuela; GeoBioTec - Geobiociências, Geoengenharias e Geotecnologias; Bioresources 4 Sustainability (GREEN-IT); Instituto de Tecnologia Química e Biológica António Xavier (ITQB); MDPI - Multidisciplinary Digital Publishing Institute
Rice bran oil (RBO) is a valuable ingredient extracted from rice bran (RB), a side stream of polishing rice grain in the milling process. RBO is rich in bioactive ingredients with potential health benefits, such as gamma-oryzanol (GO) and gamma-aminobutyric acid (GABA). Despite its benefits, the quality of RBO depends on the degree of stabilisation of the RB, which is easily affected by lipase enzymes, and thus needs an effective treatment prior to RBO production. To assess the potential of the microwave-assisted method for RB stabilisation and RBO extraction, three Carolino rice varieties (Ariete, Teti, Luna) were tested. The effect of RB stabilisation was evaluated via acid value, water absorption, and GO and GABA levels. The RBO yield was optimised by solvent, temperature, and solvent-to-sample ratio, and the GO and fatty acid levels were determined. The RB stabilisation for the Luna variety did not affect the GO and GABA; for the Ariete and Teti varieties, the GO decreased by 34.4% and 24.2%, and the GABA increased by 26.5% and 47.0%, respectively. The GO levels in RBO samples were not affected by RB stabilisation. The RBO nutritional value was confirmed by the suitable ratio (>2) between polyunsaturated (PUFA) and saturated fatty acids (SFA), with the Teti variety presenting the highest ratio.
Evaluation of Starch Hydrolysis for Glycemic Index Prediction of Rice Varieties
Publication . Pereira, Cristiana; Menezes, Regina; Lourenço, Vanda; Serra, Teresa; Brites, Carla; Centro de Estudos de Doenças Crónicas (CEDOC); NOVA Medical School|Faculdade de Ciências Médicas (NMS|FCM); CMA - Centro de Matemática e Aplicações; Instituto de Tecnologia Química e Biológica António Xavier (ITQB); Bioresources 4 Sustainability (GREEN-IT)
Rice consumed as white cooked polished grain has been considered a high glycemic index (GI) food, particularly compared with other starchy foods. However, the levels of rice GI based food can vary among different rice types and food processing technologies. Rice GI variation can be affected by several factors such as rice variety, the genetic background of rice as well as due to crop edaphoclimatic conditions. The main difference in rice starch composition that influence GI is the amylose content. Besides chemical composition of rice, the gelatinization characteristics and food processing can also contribute to starch retrogradation, thus increasing the level of resistant starch with a great influence on GI. To understand the glycemic response of rice types differing in amylose and viscosity profiles, four rice samples were analysed and compared with standard and resistant HI-MAIZE corn starches. An in vitro enzymatic starch hydrolysis procedure was applied to estimate GI. The results indicate substantial differences in the starch hydrolysis of the two corn starches. Starch hydrolysis tended to be more rapid and efficient for ‘Waxy’ and ‘Ceres’ (intermediateamylose) rice types than for ‘Maçarico’ (high-amylose rice). In addition, the data show that Maçarico variety has the lowest estimated GI and the highest retrogradation rate compared with ‘Waxy’, ‘Ceres’ and ‘Basmati’ type. The results obtained reinforce the importance of knowing amylose content and viscosity profiles for prediction of rice glycemic responses.
Unidades organizacionais
Descrição
Palavras-chave
Contribuidores
Financiadores
Entidade financiadora
Fundação para a Ciência e a Tecnologia
Programa de financiamento
CEEC IND 2018
Número da atribuição
CEECIND/01934/2018/CP1585/CT0004