Chakkrapong Assawapromtada. Sensory acceptability and nutrient stability of double-fortified wheat flour. Master's Degree(Food and Nutrition for Development ). Mahidol University. : Mahidol University, 2008.
Sensory acceptability and nutrient stability of double-fortified wheat flour
Abstract:
Wheat flour in Thailand is produced from at least 11 large modern millers. Due to the
increase in wheat flour consumption in the country, wheat flour has become an interesting
vehicle for research into micronutrient fortification. Cake (low extraction) and all-purpose
(high extraction) wheat flours were fortified with iron and folic acid and tested for shelf
stabilities under accelerated conditions (fluorescent light, 40± 2ºC) for 3 months, after being
packed in 250 g polyethylene, laminated film (OPP/PE/L-LDPE/EAA), and woven
polypropylene bags. Each kind of wheat flour was fortified with 51 ppm Fe from either
ferrous sulfate or ferrous fumarate, or 102 ppm Fe from elemental iron either H-reduced (Hreduced
EI) or electrolytic (Electrolytic EI), and 1.4 ppm folic acid. Before the shelf stability
test, the double-fortified cake and all-purpose flours were used for preparing angel cake,
cookies and fresh alkaline noodles and evaluated for their differences compared to products
made from unfortified flours. This was done by using the sensory evaluation method, i.e.
sensory difference from control test (n=24). Ferrous fumarate affected sensory quality the
most, therefore was eliminated from the study. During storage, the double-fortified wheat
flours (DFW) were analyzed for color and oxidative rancidity by spectro-colorimeter and
thiobarbituric acid reactive substances (TBARS) respectively; difference from control on
rancidity and color by sensory evaluation (n=24); iron and folate retention by Atomic
Absorption Spectrophotometer and microbiological assay (Lactobacillus casei), respectively;
and moisture content and Aw by oven drying and water activity meter. TBARS of DFW and
unfortified flours increased slightly, but significantly during the 1st months (0.41-0.71 to 1.10-
1.90 mg MDA/kg), and increased substantially in the 3rd months (1.10-1.90 to 2.00-3.43 mg
MDA/kg). Significant differences in rancidity intensity were found in DFW fortified with
ferrous sulfate packed in PE and laminated film bags after 2-3 months storage. L*, a*, b*
colors of all DFW were significantly different from unfortified flours; however they were not
significantly detectable by sensory evaluation. Reductions in moisture content and Aw during
storage were significant with final values of 9-10% and 0.33-0.45, respectively. After 3
months storage, there were no significant changes in iron content, while folate in DFW
retained > 90%. The highest losses of folate in unfortified flours were 17-25%. Per serving,
DFW fortified with ferrous sulfate and elemental iron provided Fe of 10.5 and 20.4% RDI,
respectively; and 21% RDI of folic acid.