Document Type : Original Article
Authors
1
Food Sci. Dept., Fac. Agric., Zagazig Univ., Egypt
2
. Food Sci. Dept., Fac. Agric., Zagazig Univ., E
3
Res. Inst., Agric., Res. Cent., Cairo, Egypt
Abstract
The effect of drying methods on physicochemical and cooking properties of rice (Sakha 101) was studied. Paddy rice samples were subjected to four different drying methods,raw or reference rice) which was dried by ambient air ventilation,sun drying, hot air drying and roasting drying.Also, puffed snacks from rice grains were produced from rice samples. The results showed that, a grain of rice filled, a grain of rice filled ratio, a grain of rice empty and a grain of rice empty ratio for testing sample were 9.15 g, 91.5%,0.85 g and 8.5%,respectively.While in the reference sample were 9.67 g, 96.7%,0.33 g and 3.3%, respectively. There were no significant differences in the protein contents among the rice samples treated with different drying methods.However control sample which possessed the significantly highest protein content (6.64%), moisture, fiber and amylose were 14.33, 1.40 and 21.34% respectively compared with the other rice samples treated with other drying methods.Contents of moisture, fiber and amylose decreased by increased drying temperatures. In addition, control sample contained lower contents of fat ( 0.85%) compared with the other rice samples treated with other drying methods, contents of fat and ash increased by increased drying temperatures. The drying methods had affected the amylose contents in dried paddy rice. Amylose contents decreased by increased drying temperatures.Control sample had the highest cooking time (21.40 min) and water absorption (3.62), but it gained the lowest rehydration ratio (1.42),while roasting dried sample showedthe lowest cooking time (19.70 min) and water absorption (2.40), but it gained the highest rehydration ratio (1.68).The cooking time and water absorption decreased when the drying temperature increased.Puffed rice sample prepared from control dried rice which recorded higher puffed yield (84.70%) and expansion ratio (2.28), while recorded lower expansion volume (2.24 ml/g) and bulk density (0.77) compared with other treatments. There were no significant differences in all the proximate chemical composition in all treatments expect amylose content.Puffed rice sample prepared from control dried rice recorded higher amylose content (18.34%) compared with other treatments. Puffed rice sample prepared from control dried rice recorded higher scores for all organoleptic characteristics compared with the other salty puffed rice. In addition, all salty puffed rice samples showed high acceptability scores.
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