Development of nutritionally enriched multigrain breads with functional properties
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Date
2022
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Abstract
The present study was carried out to formulate multigrain breads and to determine their physical characteristics, nutritional compositions, functional properties and the efficacy in vivo. Five different categories of multigrain breads were formulated incorporating individually ragi, barley, quinoa, buckwheat and soyflour to wheat. Additionally, fenugreek seed flour and wheat bran were also added in a few formulations. Under each category, several proportions were tried to develop a total of 44 different multigrain breads. Bread formulated with refined wheat flour (60%) and whole wheat flour (40%) served as the control. All 44 formulations were subjected to organoleptic evaluations and based on the evaluations, one bread from each category was selected for further physico-chemical and in vivo studies. Soyflour incorporated formulations were not selected as it had a very low score of organoleptic evaluation. There were a total of 4 breads selected from 4 different categories of ragi, barley, quinoa and buckwheat incorporated breads. The selected breads were subjected to physical parameters i.e. loaf weight, loaf volume, specific volume, colour and texture; proximate compositions; minerals; functional properties (bioactive compounds) and glycemic index using standard methods.
The loaf weight of the breads ranged from 434.49±0.98g to 444.28±0.56g. The loaf volume of the control bread, barley bread, quinoa bread, ragi bread and buckwheat bread were 1486.32±0.64cm3, 1400.22±0.44cm3, 1300.32± 0.65cm3, and 1170.28±0.56cm3 respectively. Differences in loaf weight were found to be statistically significant (p≤0.05) among the breads. The specific volume for control bread, barley bread, quinoa bread, ragi bread and buckwheat bread were found to have 3.42±0.75cm3/g, 3.23±0.38cm3/g, 2.99±0.60cm3/g, 2.74±0.41cm3/g, and 2.65±0.51cm3/g respectively. Difference of means for all the bread samples was found to be statistically (p≤0.05) significant. The L* value in regards to the crust colour ranged from 52.12± 0.10 in the buckwheat incorporated bread, to 67.50± 1.15 in the control bread. The crust colour of the barley incorporated multigrain bread (63.80± 2.60) was found to have relatively lighter shade with similar (p≥0.05) L* values to T₀ (67.50± 1.15). The highest a* values were found in the ragi incorporated bread (4.353±0.26) and the least in the control bread (2.09±0.05). The highest b* values were recorded in the quinoa incorporated bread (22.11±0.19) and the least in the ragi incorporated bread (14.76±0.64). Significant (p≤0.05) difference was found for b* colour parameters
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among the selected multigrain breads. The highest value for hardness (1.60±0.58 kg) was observed in the buckwheat incorporated bread and the lowest value (0.33±0.56kg) of hardness was observed in the control bread. There was significant (p≤0.05) difference between the means of T0 and the selected multigrain breads. The cohesiveness of the multigrain breads ranged from 0.95±0.43 sec in the quinoa incorporated bread to 0.40±0.11 sec in the barley incorporated bread. Observation on cohesiveness of control bread and barley incorporated multigrain bread were statistically (p≥0.05) similar. The highest (1.42±0.77) springiness was found in the ragi incorporated bread and the lowest (0.33±1.09) in the barley incorporated bread. There was significant (p≤0.05) difference in the values among the multigrain breads. The chewiness ranged from 1.50±1.42 kg sec in the buckwheat incorporated bread to 0.064 kg sec in the control bread. Differences of means for all the bread samples were found to be statistically (p≤0.05) significant.
Moisture content of the developed bread samples were statistically (p≤0.05) different, with the buckwheat incorporated bread reporting the highest (39.96±0.23g/100g) moisture content. The multigrain breads had significantly (p≤0.05) higher levels of crude fat as compared to control bread, with quinoa incorporated bread containing the highest (4.82±0.41g/100g) fat content. Protein content was found to be highest in the quinoa incorporated bread (14.28±1.65g/100g) and the least for ragi incorporated bread (10.23±0.39g/100g). Crude fibre content ranged from 1.09±0.62g/100g to 2.53±0.55g/100g with maximum crude fibre content reported in the quinoa incorporated bread. The ash content of the multigrain breads differed significantly (p≤0.05) from control, with quinoa incorporated bread reporting the maximum content. The highest carbohydrate content was seen in the ragi incorporated bread, which was similar (p≥0.05) to the buckwheat incorporated bread. The energy content of the breads ranged from 239.56±0.58 kcal in the ragi incorporated bread to 302.2±0.49 kcal in the quinoa incorporated bread. There was significance (p≤0.05) increase in the mineral content (calcium and iron) of the multigrain breads from the control. The highest calcium content (173.35±1.50 mg) was found in the ragi incorporated bread and the highest iron content 16.91±0.66 mg was reported the buckwheat incorporated bread. The dietary fibre content of the multigrain breads were statistically higher (p≤0.05) compared to control bread. The total dietary fibre content ranged from 12.10±0.45g/100g to 13.82±1.65g/100g.
In order to evaluate the functional properties of the multigrain breads, the total antioxidant capacity, total phenolics and total flavonoids were studied. Per cent
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total antioxidant capacity of the selected multigrain breads based on DPPH assay ranged from 25.88 ± 0.37 per cent to 39.73± 0.87 per cent in control and buckwheat incorporated bread respectively. The present findings of the formulated breads ranged from 1.055± 0.22 mg GAE/g (control bread) to 2.312±1.58 (quinoa incorporated bread). There was statistical (p≤0.05) difference in the phenolic content of control and the multigrain breads. The total flavonoids contents for control, ragi, buckwheat, barley, quinoa and buckwheat incorporated breads were 0.119±0.45 mg QE/g, 0.233±0.51 mg QE/g, 0.130±0.83 mg QE/g, 0.227±0.46 mg QE/g and 0.228±0.72 mg QE/g respectively. The values for the selected multigrain breads differed statistically (p≤0.05) from control.
Glycemic index (GI) of four selected bread formulations were determined in-vivo using human subjects and found that quinoa incorporated bread had the lowest GI of 42.00±0.83, followed by 53.00±0.39 in the buckwheat incorporated multigrain bread, 54.20± 1.23 in the ragi incorporated multigrain bread and 56.00±0.76 in the barley incorporated multigrain bread, which were all lower than control (69.20±1.84). The statistical analysis showed that the GI of the multigrain breads analyzed differed significantly (p≤0.05). To study the efficacy of the formulations the one having the lowest GI, i.e. the quinoa bread was selected for a feeding trial. An amount of 100g of bread per day was fed to each human subjects (n=21) in the age group of 20-50 years for a period of 90 days. Efficacy was determined from pre and post blood profile in terms of blood glucose, glycosylated haemoglobin (HbA1c) and lipid profile were studied. The blood glucose levels before intervention with multigrain bread was 86.96± 15.32 mg/dl, and after intervention with multigrain bread was 84.25±18.26 mg/dl. The lipid profile values observed before intervention with multigrain bread was 180.38±36.08 mg/dl (total cholesterol), 175.11±59.60 mg/dl (triglycerides), 53.17±7.64 mg/dl (HDL), 94.02±32.75 mg/dl (LDL), and 35.33±12.25 mg/dl (VLDL) and after intervention with multigrain bread, 160.43±31.75 mg/dl, 108.09±39 mg/dl, 52.51 ±7.93 mg/dl, 87.52 ± 26.19 mg/dl total cholesterol, triglycerides, HDL, LDL, VLDL respectively. There was significant (p≤0.05) decrease in levels of triglycerides, total cholesterol, LDL and VLDL level. From this study it was observed that multigrain breads having good nutritional and functional profile can be prepared, commercialized for health benefits.