الفهرس 
WheatOnly 14 pages are availabe for public view
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Abstract
Antioxidants are substances or nutrients in our foods which can prevent or slow the oxidative damage to our body. When our body cells use oxygen, they naturally produce free radicals (by-products) which can cause damage. Antioxidants act as ”free radical scavengers” and hence prevention and repair damage done by these free radicals. Health problems such as heart disease, diabetes, cancer are all contributed by oxidative damage. Cereals such as wheat, rice, corn, and barley are primary sources of carbohydrates and bioactive compounds such as dietary fibre and antioxidant group. Positive physiological role of cereal grains is mainly attributed to dietary fibre. However, recent findings revealed that the cereals also contain phenolic compounds that have antioxidant activity and prevent diseases in humans. Whole grains are known to contain a number of polyphenols and other antioxidant compounds, which may work synergistically to optimize human health
Therefore, the present study was carried out to evaluate nutritional quality and antioxidant properties of selected some Egyptian wheat varieties.TPC and TFC of wheat fractions (whole wheat, wheat flour and bran layer) were also evaluated, and compared effect of different solvent systems on antioxidant extraction efficiency. Relationship between technological
treatments and TPC, antioxidant activity for wheat fractions had been studied.
The obtained results of this study are summarized in the following points:
1. Investigated wheat varieties
Wheat of six varieties were grown in both lower and upper Egypt. The analyzed lower Egypt varieties were Gemiza-7, Gemiza-9 and Sakha- 61, while the upper Egypt varieties, Giza-168, Beni-suef-3 and Seds-1. All the six varieties considered are common wheat except Beni-suef-3 is durum wheat.
2. Approximate chemical composition of the six wheat varieties
The proximate compositions were evaluated for six wheat varieties. The mean value for the moisture content varied from 10.33 to 12.88%. The data indicated that variety Sakha- 61 had higher moisture content than the rest other varieties. The major chemical compositions consists of protein, fat, ash and crude fibre were ranged between 9.61-11.51%, 1.09-1.55%, 1.11-1.65% and 2.77-3.44%, respectively. The Gemiza-9 variety had the greatest fat content (1.55%), whereas, Beni-suef-3 had greatest crude fiber contents (3.44%). The levels of total carbohydrate were ranged from 73.01 to 71.65%. The data of energy was ranged through 334.86 - 346.68 Kcal. These results indicated that the Beni-suef-3 and Gemiza-9 varieties are more nutritious than all other wheat varieties.
3. Antioxidant activity (RSA), total flavonoid contents and total phenolic contents for free and bound fractions in the six tested whole wheat samples
Mean values of free RSA among the tested six wheat varieties examined between 8.55% and 14.92% for Gemiza-7 and Giza-168, respectively. While, bound fraction were arranged between 24.87% in durum wheat (Beni-suef-3) and 42.09% in common wheat (Gemiza-9). Beni-suef-3 was the best among all varieties with regard to free fraction of flavonoid contents being 259.11μgRE/g. However, when the flavonoid contents in bound fractions was estimated the tested upper Egypt varieties showed superiority upon the lower Egypt varieties where their the values ranging between 9.44 to 13.64 μgRE/g and 3.80 to 11.01 μgRE/g, respectively. The results of total phenolic contents proved that Sakha-61 variety was the highest concentration (3.45 mgGAE/g of whole wheat).
4. Antioxidant activity (RSA), TFC and TPC for free and bound fractions in flours (82 % extraction) of the six tested wheat varieties
The determined mean values for free radical scavenging activity content in wheat flour extracts varied from 11.27 to 7.72 %. The mean values for bound fraction showed that the Beni-suef-3 variety had the highest RSA (11.94%). There was wide variation in both free and bound flavonoid extracts among different varieties under study (P<0.05). The free fractions in flour sample extracts were ranged 204.57-54.25 μg RE/g. The highest flavonoid extract in bound fraction was observed in the Seds-1 variety followed by Gemiza-9. The mean values for TPC
varied from 1.60 to 2.81 mg/g DM. Sakha- 61 variety had the least TPC followed by the Gemiza-7 variety, whereas, the Gemiza-9 variety had the highest TPC (2.81mg/g).
5. Antioxidant activity (RSA), TFC and TPC for free and bound fractions in the six tested wheat bran samples
RSA in free fraction extracts of wheat bran ranged from 20.17 to 32.77%. Furthermore, bound radical scavenging activity in bran were between 41.06- 65.16% for Seds-1and Beni-suef-3, respectively. Mean flavonoid were found as 110.12 and 44.12 μgRE/g bran in free and bound durum wheat brans, respectively. The calculated TFC of free and bound extracts for wheat bran fractions established that Beni-suef-3 was the highest content in both fractions for TFC. The TPC in wheat bran extracts ranged from 3.51 to 4.66 mg/g.
6. Determination color parameters for whole, bran and flour of the six wheat varieties
The L* values for whole wheat of six varieties were ordered from 73.55 (Gamiza-9) to 61.11 (Beni-suef-3), a* values ranged from 3.65 (Gamiza-9) to 5.66(Beni-suef-3), b* values dropped from 16.92 (Beni-suef-3) to 12.60 (Gamiza-9). Based on Hunter parameters it can be concluded that the Beni-suef-3 was more yellowness than Gamiza-9. Regarding wheat flour color values showed high values of lightness (L*= 83.86 - 89.95) and low values for redness and yellowness ranged between 0.60 to 1.45 and 7.75 to 13.61, respectively. Also, the durum wheat had the lowest lightness color which reflected on color of flour obtained from this variety. All bran samples revealed the low L* values and the high values of a* and b* ranged 59.30-66.31, 5.32-6.76 and 14.76-17.36, respectively.
from the previous data that explained the relationship between TFC and yellowness; saturation values for wheat wheat the Beni-suef-3 variety had highest TFC value (270.37 μg RE/g whole wheat) followed by Gamiza-7 (224.63 μgRE/g). Likewise, the same trend was observed in bran samples. Finally, the TFC was affected by wheat cultivars color.
7. Choosing the best varieties for the study
Determination the antioxidant activity for whole wheat confirmed that the Beni-suef-3 and Gemiza-9 gave the highest values for TFC and RSA, respectively. TFC of the bran extracts prepared from six wheat varieties differed significantly and ranged from 77.78 to 154.24 μgRE/g. The bran of Beni-suef-3 had the highest TFC. The same trend was observed where the RSA of Beni-suef-3 was the highest of antioxidant activity. Based on the results of statistical analysis, Beni-suef-3 (durum wheat) and Gemiza-9 (common wheat) varieties were selected as the best whole wheat and bran fractions for this study.
8. Effect of different solvents on the extraction antioxidant contents from whole wheat and bran fractions of Beni-suef-3 and Gemiza-9 varieties
For two selected wheat varieties Beni-suef-3 and Gemiza-9, significant difference (p < 0.05) in TFC was observed using three different solvents. These results indicated that possible influence of extracting solvent on TFC for all the wheat extracts. In fact, extraction using Ethanol/H2O (70:30, v/v) gave the highest RSA and TFC for the two tested wheat varieties. On the other hand, the data recommended that the fifty percent
acetone (v/v) was the better solvent to extract phenolic compounds.
9. Effect of particle size on antioxidant activity in wheat bran of Gemiza-9 and Beni-suef-3 varieties
The results of particle size index and cumulative yield suggested that the wheat bran sieved through 710μm mesh considered as coarse fraction; sieved through 300μm mesh as medium fraction and sieved through 212, 150, 75 μm mesh can be collected as fine fraction. Wheat bran fractions (coarse, medium and fine) of Gemiza-9 and Beni-suef-3 varieties were compared with regard antioxidant activity RSA, TFC and TPC. The ability to scavenge DPPH radicals by bran fractions significantly differed for coarse, medium and fine extracts, and the ability order of: coarse > medium > fine, as the mean values were 33.02, 32.32 and 31.61, respectively. The findings of TPC proved that the medium fraction did not significantly differed from the coarse fraction.
10. Physical properties for Gemiza-9 and Beni-suef-3 wheat bran at different particle sizes
Bulk density is an important parameter that determines the packaging requirement of a product. The Gemiza-9 coarse and medium bran fractions had a bulk density of 0.61 and 0.57 gml–1, respectively. Nevertheless, the coarse and medium bran fractions for Beni-suef-3 variety had a bulk density 0.49 and 0.44 gml–1 , respectively. The obtained mean values of water holding capacity for the medium Gemiza-9 bran samples were 5.14 g water/g bran
sample. The coarse bran samples for the two selected varieties had an oil holding capacity of 4.14 and 5.03 g oil/ g bran sample, which comparative with medium fraction 2.45 and 2.81g oil/ g dry sample for Gemiza-9 and Beni-suef-3, respectively.
11. Effect of technological treatments on RSA, TFC and TPC for Gemiza-9 whole wheat and Beni-suef-3 wheat bran
11.1. Effect of roasting time for Gemiza-9 whole wheat on RSA, TFC and TPC
The TFC in whole wheat ethanolic extracts were measured before and after roasting process for 4, 8 and 12 min. The TFC in control samples increased significantly from 239.18 to 435.75 μg RE/g after 12 min roasting. On the other hand, TPC values of unroasted and roasted samples for 4, 8 and 12 min are 2.57, 3.11, 2.57 and 1.46 mgGE/g, respectively. The results showed that the amount of TPC increased significantly as the roasting time 4min and decreased by roasting for 12 min. The data of antioxidant activity can observed that the roasting for 12 min had the best DPPH• RSA.
11.2. Effect of boiling treatment on RSA, TFC and TPC for Gemiza-9 whole wheat
RSA/DPPH estimates extended in boiled whole wheat (26.0%) when compared with non-boiled whole wheat (23.90%) in Gemiza-9 variety. Results of TFC displayed that thermal treatment enhanced availability of the TFC. The mean values of TFC were 239.18 and 261.79 μg RE/g for control and boiled whole wheat, respectively. The phenolic compounds were very sensitive to heat treatment, thus, it decreased from 2.57 mg
GAE/g bran sample in control to 0.28 mg GAE/g bran in boiled sample.
11.3. Effect of fermentation treatment on RSA, TFC and TPC for Beni-suef-3 wheat bran
All samples showed a significant increase in TPC and effective antioxidant activities highest TPC (4.17 mg/g) observed in fermented bran sample. RSA increased from 42.10% in native unfermented sample to 50.80% for fermented sample. TFC in the examined wheat bran extracts control sample was the greatest (248.49 μg RE/g).
12. Application Technology for whole wheat and bran fractions
12.1. Application of roasted Gemiza-9 whole wheat in cereal bars
The cereal bar prepared from roasted whole wheat for 4 min had the highest score (9.6) for both taste and stickiness. Statistically analysis showed that there were relationship between roasting times and sensory parameters (taste, flavor and Crunchiness) for all samples of cereal bars. It can conclud that, increasing the roasting time gave rise negative effect on acceptability of cereal bars.
12.2. Application of roasted Gemiza-9 whole wheat in
chocolate
The roasting time influenced the sensory perceptions in terms of aroma and melting attributes. According to the gained values for overall acceptability, chocolate enrichment with roasted wheat for 8 min was positively altered their aroma.
Similar sensory acceptances were also observed for chocolate roasted for 4 and 12 min in their terms of aroma and melting attributes. Chocolate roasted for 12 min scored highest values of color (9.7).
12.3. Application of deliob Gemiza-9 whole wheat for 90 min in producing chocolate pudding
Sensory characteristics for pudding fortified with 15 and 25% of boiled whole wheat resaved the highest scores for acceptability. Pudding prepared with 50 and 75 % boiled wheat gave low score for mouth coating attribute, may be due to high bran concentration.
12.4. Application of fermented Beni-Suef-3 wheat bran in cookies
12.4.1. Antioxidant activity RSA, TFC and TPC for cookies enrichment with fermented Beni-Suef-3wheat bran
Mean values of TFC for the different cookie samples ranged from 327.35 to 284.05 μg/g for cookie prepared by 5% and 10% fermented wheat bran, respectively. Also, the data of RSA indicated that cookie samples prepared using 5% of fermented wheat bran had higher antioxidant activity than of used unfermented bran. TPC for cookie samples prepared with 10% fermented bran had the highest value being 3.16 mg/g followed by that used 5% fermented bran being 2.09 mg/g
12.4.2. Physical evaluation of cookies prepared using different ratios of fermented Ben-suef-3 bran
The mean values of the diameter of different cookies samples ranged between 240.0 and 289.5 mm. The lowest values were found for the cookies produced from 5% ratio
replacement with unfermented Beni-Suef-3 wheat bran. On the other hand, the highest value for thickness (70.22mm) was found in cookies prepared with whole wheat flour. Spread factor is the ratio that depends on the values of the thickness and diameter of the cookies. Highest spread factor (52.49) was given for cookies produced from 5% replacement of fermented bran
12.4.3. Sensory evaluation of cookies prepared using different ratios of fermented Ben-suef-3 bran
Our results declared that the highest taste score given for cookies prepared from 10% replacement ratio with fermented wheat bran. Cookies prepared from whole wheat flour gave lowest score for taste (7.52). The scores for color ranged between 9.25 to 7.63, also there was no significant different between cookies prepared from replacement 5% fermented and unfermented wheat bran. The lowest color acceptability score was observed in cookies made from whole wheat flour. It is clear from the results that highest score was obtained by cookies prepared from 10% fermented bran, while lowest obtained by cookies prepared from whole wheat flour.