Effect of heat moist treatment on functional properties of rice flour of selected traditional rice varieties in Sri Lanka
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Date
2015
Journal Title
Journal ISSN
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Publisher
Uva Wellassa University of Sri Lanka
Abstract
Rice flour is good food crop which has been found to be an important calories source. Gluten-free
nature can play important role in preventing celiac problem. The substitution of selected traditional
rice flour to the wheat flour can provides beneficial nutraceutical properties than the commercial
hybrid rice flour. The traditional rice varieties contain higher amounts of Glutamic acid, higher
concentrations of vitamins, richer in fiber and a lower Glycemic index (Oyarekua and Adeyeye,
2008). Heat moisture treatment (HMT) is used to modify the rice flour which can change the
functional properties of rice flour. The functional properties of flours play important role in the
manufacturing of bakery products. These hydrothermal treatments could suppress granule swelling,
retard gelatinization and increase starch paste stability. HMT of rice flour could enhance the cooking
and textural qualities of rice flour (Sandoval et al., 2008).
Methodology
Four different traditional rice varieties (Madathuwalu, Kaluhenati, Pachaperumal and Rathadal) were
obtained depending on their availability and the nutritional status, from Rural Network Farmers
organization and certified the varieties from the rice research institute, Bathalegoda, Sri Lanka.
Subsequently, eight percent of bran was removed from all the brown rice grains. White rice flour
were obtained from the rice grains by dry grinding process of Pin Mill machine sieving the 160 μm
mesh (IPHT, Anuradhapura). The moisture content of selected rice flour was adjusted to one percent,
followed by heating at 100 C for one hour (HMT 01) and two hours (HMT 02) and soaking slightly
at 80 C for five hours by adding 65% (w/w) of excess water.
Native and modified rice flour (Madathuwalu F1, Kaluhenati F2, Pachaperumal F3 and Rathadal F4)
obtained from the rice grains before and after different flour modification methods were analyzed
separately for different functional properties such as water solubility (WS), swelling power (SP),
water absorption index (WAI) and bulk density. Native rice flour obtained from traditional rice
varieties were maintained as a control for each treatment. Experiments were conducted in triplicates
and data obtained were analyzed using ANOVA in model Minitab 16.0 software.
Result and Discussion
The functional properties of rice flours play important role in the manufacturing of bakery products.
The bulk density obtained for both HMT 1 and HMT 2 were lower than that of the native flour in F1
and F2 flour types (Fig.1 A). Further, the bulk density for treatments HM1 and HM2 were
approximately similar in F2 and F3 flour types. The lowest significant bulk density was recorded for
the treatment HMT2 in F4 flour type compared to all other treatments (p < 0.05).
Description
Keywords
Science and Technology, Technology, Rice Research Development, Agriculture, Traditional Rice