Author(s):
Correia, Paula 
; Santos, Tania ; Lemos, Diogo ; Brites, Carla ; Guiné, Raquel
Date: 2014
Persistent ID: http://hdl.handle.net/10400.19/2121
Origin: Repositório Científico do Instituto Politécnico de Viseu
Subject(s): rice; amylose
Description
Amylose content is considered to be the most important parameter of cooking quality in rice. Presently, rice cultivars are categorized according to amylose content into three groups: low, medium and high amylose content cultivars. The specific objective of this work is to evaluate the grain amylose content of 77 cultivars, which cover Índica and Japónica subspecies, and different types of commercial rice like, aromatic (basmati and thay), wild rice, medium rice (carlose and risotto), glutinous (waxy) and parboiled rice. Generally, these types of rice are the ones commercialized in Portugal
The encountered results showed that in the same group the amylose contents were consistent, and could present great variance, as it is the case of Indica subspecies, which vary between 12.0% to 29.5%, and presenting the high amylose percentages. Thus, these intermediate amylose rices could give moist and tender upon cooking. It is also important to mention that amylose consists of linearly linked glucose molecules and is relatively resistant to digestion, hence the term “resistant starch”. This means that these rice cultivars with a greater proportion of starch in the form of amylose tend to have a lower glycemic index, and could be recommended for special diets. The low values were presented for glutinous rice (1.9% and 3.3%), which means that these type of rice do not expand in volume, are glossy and sticky, and remain firm when cooked. Intermediate values were found for parboiled rice. The majority of rice types presented low amylose content, range from 9% to 19%.
