الفهرس 
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Abstract
Industrialization of agriculture in the Arab world represent a large proportion of waste was estimated at 18.14 million tonnes per
year and represent remnants of fruit and vegetables manufacture
about 6.14% of this amount. Waste in the food industry is
characterized by a high ratio of product-specific waste. This not only
means that the generation of this waste is unavoidable, but also that
the amount and kind of waste produced, which consists primarily of
the organic residue of processed raw materials, can scarcely be
altered if the quality of the finished product is to remain consistent.
The utilization and disposal of product specific waste is difficult,
due to its inadequate biological stability, its potentially pathogenic
nature, its high water content, its potential for rapid autoxidation, as
well as its high level of enzymatic activity. The diverse types of
waste generated by various branches of the food industry can be
quantified based upon each branches’ respective level of production.
Processing of fruits, vegetables, and oilseeds result in high
amounts of waste materials such as peels, seeds, stones, and oilseed
meals. Disposal of these materials usually represents a problem that
is further aggravated by legal restrictions. Plant waste is prone to
microbial spoilage; therefore, drying is necessary before further
exploitation. The cost of drying, storage, and transport poses
additional economical limitations to waste utilization. Therefore,
agroindustrial waste often is utilized as feed or fertilizer. However,
demand for feed or fertilizer varies and depends on agricultural
production. Moreover, valuable nutrients contained in agroindustrial
wastes are lost. Thus new aspects concerning the use of these wastes
as by-products for further exploitation on the production of food
additives or supplements with high nutritional value have gained
increasing interest because these are high-value products and their
recovery may be economically attractive. It is well known that
agroindustrial by-products are rich in dietary fibers, some of which
contain appreciable amounts of colorants, antioxidant compounds or
other substances with positive health effects, while some of them,
like the oilseed meals, are rich in proteins. Some major source of
food wastes are mango (Mangifera indica), potatoes (Solanum
tuberosum L.) and onion (Allium cepa L.), some of the most popular
vegetables and fruits.
Although, many studies have been carried out to analyze these
parts of the selected vegetables and fruit and introducing in different
nutritinal and nutraceutical applications but more and more research
are still needed. Therefore, the objective of this work is to analyze
some plant by-products including onions, potatoes and mango peels
that constitute to waste for their nutraceutical values as food
ingredient thus reducing its contribution to environmental pollution.
Also, utilization of such by-products for their recovery of dietary
fibers, phenolics and antioxidants in the production of snacks will be
in the scope of this study.
The obtained results could be summarized as follow:
1. Chemical analyses of food by-products
The moisture content was ranged 5.02-7.58%, total protein
was 3.82-12.09%, crude fat was 1.01-11.21%, crudw fiber was 9.14-
27.75%, ash content was 3.72-7.31% and total carbohydrate content
was 43.21-63.51%. The PPP was recorded the highest content of
protein while ROSP recorded the highest values of moisture, crude
fat, crude fiber and ash.
2. Physical properties of food by-products
ROSP recorded the highst WHO followed by PPP and MPP
being 10.03, 7.24 and 5.19 g water/g, respectively, indicating that
the higher fiber content in ROSP hold more water compared to rest
by-products. In similar study,
3. Total dietary fiber, carotenoids and phenolics contents of
food by-products
The total dietary fiber content was ranged 47.87-64.80 g.100g-
1, total carotenoids was 89-348 mg.100g-1 and total phenolics was
1679-8946 mg EGA.100 g-1. The ROSP was recorded the highest
content of total dietary fiber and total phenolics while MPP recorded
the highest values of total carotenoids.
4. Antioxidant activities and total phenolics in selected food byproducts
Antioxidant activities of selected food by-products
The by-products powder showed considerable differences in
antioxidant activity (AA = 84.87 - 97.66 %) when it was calculated
by the four different methods used in this study. ROSP showed
strong activity because of its high phenolic content (430.70 mg
EGA.100g-1) while potato peels powder (PPP) showed relatively low
content in both antioxidant activity and the total phenolics (96.09 mg
EGA.100g-1).
For the degree of stability, ROSP recorded the lowest
decreasing followed by MPPand PPP, respectively. The values of
ROSP absorbances throught 120 min are coming well i.e.
corresponding to the line of 50 mg.L-1 of α-tocopherol. By the same
manner, MPP and potato peels powder (PPP) are coming close the
line of 50 mg.L-1 of α-tocopherol. These data proved the high
stability of the all tested food by-products when comparing with that
more comman standards α-tocopherol.
Relationship between phenolic contents and antioxidant activity
The total phenolic content of the tested food by-product
powders investigated in this study varied from 96.09 – 430.70 mg
EGA.100g-1 of dry product. All MPP, ROSP and PPP were included
in the statistical analysis, there was a positive and highly significant
(r2= 0.829, r2= 0.973 and r2= 0.934, p< 0.001) relationship between
total phenolics and antioxidant activity.
5. Effect of selected food by-products on the rheological
parameters
5.1 Farinograph parameters
− The incorporating of food by-products in dough increased the
water absorption from 58.9% for control to 60.4, 62.1 and
63.8% for dough contained 5% MPP, ROSP and PPP,
respectively.
− The dough development time and dough stability increased
from 2.5 to 3.5, 3.1 and 4.2 min with 5% incorporation of
MPP, ROSP and PPP, respectively.
− Addition of food by-products (MPP, ROSP and PPP) to flour
samples showed markedly longer stability periods than the
control samples (without the addition of food by-products).
This affect was significantly with the addition of 5% of food
by-products for wheat flour.
− from the viewpoint of dough farinograph quality number
(FQN), statiscally significant difference was found between
the control sample (without the addition of food by-products)
and the doughs with additions of 5% of food by-products (P <
0.05).
5.2 Extensograph parameters
Dough strength (Extensibility) determined by the area under
the curve and is proportional to energy needed to bring about
rupture. The incorporating of food by-products in dough increased.