Rice (Oryza sativa L.) is a type of cereal crops
of the grass family (Poaceae). It is mainly consumed mainly in the form of
whole grain contributing 20% of daily calories as a staple food for a large
population throughout the world (Bhattacharjee et al., 2002). The
changes in kernel physicochemical during cooking have been reported to vary
greatly depending upon rice varieties. Different cultivars showed significant variations in physicochemical and
cooking properties (Yadav et al., 2007). The physicochemical
characteristics include grain length, breadth, l/b ratio and kernel elongation
while the cooking qualities are amylose content (AC), gel consistency (GC) and
gelatinization temperature (GT).
According to Siddiqui et al., (2007), grain quality is a very wide
area encompassing diverse characters that are directly or indirectly related to
exhibit on quality type. High kernel elongation is an example of grain
quality which can be the key factor in the desirable cooking and eating
properties of specialty quality rice. Rice varieties that exhibit longitudinal
expansion upon cooking with a ratio of >1.60 are categorized as possessing
high kernel elongation. IRRI (1977) mentioned rice varieties such as Basmati
from India and Pakistan, Barah from Afghanistan and Sadri from Iran are known
to elongate about 100% of their original kernel length after cooking.
Cooking qualities in rice
are associated with physicochemical properties such as amylose content (AC),
gel consistency (GC) and gelatinization temperature (GT). Gelatinization
temperature is responsible for cooking time and the temperature at which starch
granule swell irreversibly with a simultaneous loss its crystalline order
during cooking. Sabouri (2009) mentioned that gel consistency is influenced the
softness while amylose content responsible for the texture of cooked rice.
varieties have drawn consumer’s attention due to their superior quality
attributes like superfine slender grains, fine cooking quality, pleasant aroma,
lengthwise elongation during cooking (Bhattacharjee et al., 2002) and
fetched premium price in the local and global market. Thus, physicochemical and
cooking characteristics are the good indicators of grain quality (Bhattacharya et
al., 1972; Sidhu et al., 1975).