PHYSICAL, CHEMICAL, THERMAL AND TECHNOLOGICAL PROPERTIES OF SOME EGYPTIAN RICE VARIETIES | ||||
| Journal of Food and Dairy Sciences | ||||
| Article 6, Volume 33, Issue 8, August 2008, Page 5893-5909 PDF (768.71 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/jfds.2008.124946 | ||||
 View on SCiNiTO | ||||
| Authors | ||||
| M. F. Osman; M. A. Abd El-Galeel | ||||
| Food Science and Technology Dept., Fac. of Agric., Kafr El-sheikh Univ., Egypt. | ||||
| Abstract | ||||
| This study was carried out to compare physical, chemical, thermal and technological properties of four rice varieties (Hybrid1, Jasmine, Waxy and Black) grown in Egypt as well as to investigate the possibility of using their rice flour as substitution of wheat flour in preparation of some bakery products namely biscuits. Physical properties such as milling output, head rice percentage and kernel physical attributes of rice varieties were measured. Chemical composition, gelatinization temperature (GT), gel consistency (GC), in vitro starch digestibility and cooking properties of rice were also determined. In addition, biscuit using milled rice flours as substitution of wheat flour at levels of 25 and 50% was prepared, and its sensory analysis as well as its functional properties were evaluated. The results revealed that Hybrid1 rice had the highest milled percentage but Jasmine variety had the highest head rice percentage. Waxy rice had the highest contents of total carbohydrates and starch. Black rice contains high content of ether extract, ash and crude fibers, but it contain lower content of total carbohydrates and starch compared with another varieties. In addition, brown rice in all varieties had higher contents of crude protein, ether extract, ash and crude fibers but it contain lower contents of total carbohydrates and starch compared with those of milled rice. Waxy rice had the highest gel consistency (GC) and gelatinization temperature (GT) among the other varieties; but it had the lowest content of amylose. Black rice had the lowest GT and the highest amylose content. Also, the results cleared that no significant differences were found among all rice varieties in starch digestibility using α- amylase. Cooking qualities revealed that Hybrid1 rice had the longest cooking time (22 min) compared to the others, while the other varieties had somewhat similar cooking time. Generally, brown rice had significantly cooking time higher than that of milled rice. Water uptake of milled rice was significantly higher than that of brown. In milled rice, water uptake were in order; Hybrid1 > Jasmine > Black > Waxy. Organoleptic evaluation indicated that, biscuit samples prepared using rice flour of studied varieties as substitutions of wheat flour until 50% were very acceptable, where most samples have sensory characteristics scores higher than those of control (wheat flour biscuit). Water loss during baking of biscuit was higher in formulas contained rice flour than that of control and it increased with increasing of rice replacement ratios. Water uptake of samples prepared with rice flours as substitution of wheat flour was significantly higher than that of control sample (free from rice flour). Water uptake values of biscuits contained higher substitution ratio (50%) were significantly higher than those of samples contained lower ones.Specific lightness of biscuit made using rice flour as substitution of wheat flour was somewhat lower than that of wheat flour biscuit with the exception of black rice was the highest. | ||||
| Keywords | ||||
| Hybride1; Jasmine; Waxy; Black rice; physical; chemical; technological properties | ||||
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