Cooking behavior of rice in relation to kernel physicochemical and structural properties.
A set of 27 rice varieties were evaluated for their morphological grain characteristics (length, width, thickness, thousand kernel weight, TKW), chemical composition (amylose, protein, and ash content) and starch properties (gelatinization temperature and enthalpy, amylose-lipid complex). In addition, cell walls were characterized by the arabinoxylan and beta-glucan contents. A rapid method for determining optimum rice cooking time was developed based on the swelling ratio; a fixed value of 2.55 gave a gelatinization level of 95% assessed by differential scanning calorimetry and translucence testing. Optimum cooking time appears positively correlated with kernel thickness and TKW but also with ash content. Confocal laser and scanning electron microscope observation of uncooked rice grains revealed different structural features (cell size) and fracture behavior: for some cultivars, the fracture showed ruptured cells, whereas for others most cells were intact. These structural differences, which may be linked to pectin content, could partly explain rice kernel cooking behavior.
Vidal
Véronique
V
CIRAD, UPR Qualité des Aliments Tropicaux, 73 avenue J.F. Breton, 34398 Montpellier Cedex 5, France, Institute of Food Science and Nutrition, ETH Zürich, CH-8092 Zürich, Switzerland.
Pons
Brigitte
B
Brunnschweiler
Judith
J
Handschin
Stephan
S
Rouau
Xavier
X
Mestres
Christian
C
D000688:Amylose / Q000032:analysis; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D006358:Hot Temperature; D008855:Microscopy, Electron, Scanning; D012275:Oryza / Q000737:chemistry*; D010940:Plant Proteins / Q000032:analysis; D012639:Seeds / Q000033:anatomy & histology* / Q000737:chemistry*; D013213:Starch / Q000737:chemistry; D013997:Time Factors
D010940:Plant Proteins; D013213:Starch; D000688:Amylose