Effect of Blend Ratio on the Quality and Sensory Properties of Wheat Breads Made from Oyster Mushroom (Pleurotus Ostreatus ) Powder
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Date
2011-07-23
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Addis Ababa University
Abstract
Breads were prepared by substituting wheat flour with oyster mushroom (Pleurotus ostreatus)
powder (OMP). The objectives of the study was to study the possibility of bread making by
using OMP and wheat flour (WF) at levels of 2%, 4%, 6%, 8% and 10% and evaluate the effects
of substitution on flour functional properties, bread qualities, nutritional composition and sensory
attributes. Wet gluten content of composite flours was lower as compared to control flour,
indicating a destruction of gluten matrix of wheat flour. Substitution of OMP at all levels except
2% had significant effect (p < 0.05) on mean wet gluten content of flour, values ranging from
0.153g/g - 0.301 g/g for control flour and 10% substituted flour respectively. Blending
proportion generally significantly (p < 0.05) affected the mean water absorption capacities. The
values varied between 0.689 ml/g and 0.821 ml/g for control and 10% substituted flour
respectively. Blending proportion also had an effect in bread characteristics, resulting a
significant (p < 0.05) increase on loaf weight of breads and a significant decrease (p < 0.05) in
loaf volume and height of breads as blending proportion increased. The mean loaf weight of
breads varied from 127.14g- 137.41g for control and 10% substituted flour respectively. Control
breads had mean loaf volume 686.67cm3 while breads substituted with 10% OMP had mean loaf
volume of 236.67cm3. The proximate composition of breads resulted an increase in moisture
content of breads at the crumb as blending proportion increased. Substitution also caused an
increase in protein content of breads up to 16.5%. Lysine content of experimental breads varied
from 0.23 g/100g – 0.31 g/100g resulting a significant (p < 0.05) increase. The total ash values
had a significant increase (p < 0.05) as substitution levels increased, means ranging from 1.51
g/100g – 2.48 g/100g for control breads and breads with 10% OMP respectively. The sensory
evaluation using a nine point hedonic scale indicated that control breads were more preferred by
panalists than OMP substituted breads. Breads substituted with 6% OMP had no significance
difference (p > 0.05) in terms of appearance and color but recorded significant differences in
terms of taste, flavor and mouth feel. Sensory evaluation revealed that breads with appreciable
nutritional value and acceptable scores can be prepared with inclusion of 6% OMP, since their
overall acceptability scores lies above the “like slightly” score.
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Keywords
Oyster Mushroom, OMP Supplemented Bread, Proximate Composition, Acceptability