الفهرس 
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Abstract
This investigation was carried out on seeds of some sunflower varieties and hybrids nawly : Hybrid 102, Euroflor and Vidok. These varieties were obtained from the Field Crops Rese-arch Institute (FCRI), Agriculture Research Center (ARC) at Abnob-Assiut,Egypt.
During the course of this work the following topics were covered:
- Gross chemical composition of whole sunflower seeds and kernels from different varieties.
- Comparative studies on the physical properties and ch-emical characteristics of the resulting crude oils.
- Fatty acid composition and unsaponifiable matters of oils extracted from sunflower seed varieties by gas liq-uid chromatography.
- Effect of refining processes (degumming, neutralizati-on, bleaching and deodorization) on oil characteristics, fatty acid composition, tocopherols and phospholipids content.
- Effect of storage period on some characteristics and fatty acid composition of sunflower oil.
The obtained results could be summarized as follows:
1- Gross chemical composition of sunflower seeds from differ-ent varieties and hybrids:-
1.1 – Gross chemical composition of whole sunflower seed :-
The proximate composition of whole Euroflor, Vid-ok, and hybrid (102) of sunflower seed were determined and the results showed the following:-
- The weight of 1.000 seeds ranged between 43.10g. (for Hybrid,102) and 56.30g. (for Vidok variety). These difference could be explained by the fact that for achenes and the oilseed varieties exist a relationship between the size of achene and the weight of 1.000 seeds.
- The kernel percentage was 71.20, 71.44 and 74.00 for Hybr- id (102), Vidok and Euroflor, respectively. While, hull perc-entage was 26.00; 28.56 and 28.80 for Euroflor, Vidok and Hybrid (102), respectively.
- Both percentage of Kernel and hull depended on the cultivation zone and the purpose of seed production (for confetio-ns and birdseed or oil).
- The moisture content ranging from 4.18 and 4.83%.
- The Dry matter percentage ranged between 95.17 and 95.82%.
- The ash content ranging from 4.25 and 4.40% (on DWB).
- The oil content ranging from 40.89 and 46.69% (on DWB).
In general, the all studied sunflower seed varieties had high oil content.
- The protein content ranging from 16.72 and 27.16% (on D- WB). These results show that for achene of sunflower vari-eties and hybrids exist an inverse relationship between oil content and protein content.
- The fiber content in whole sunflower seeds ranged from 17.97 % (on DB in Euroflor varieties) to 23.52% (on DB in Vidok varieties).
- The carbohydrate content (soluble and non soluble sugars) was 7.20% (on DB); 7.68% and 6.28% for Hybride (102), Euroflor and Vidok, respectively.
1.2 – Gross chemical composition of sunflower seed Kernel of three cultivaris :-
The results obtained herein indicated that:-
- The sunflower seed Kernel of vidok varieties had the hig- hest value of moisture content (5.47%) followed by Hybrid (102) 3.94% and the lowest value was found in Euroflor variety (3.03%).
- The dry matter of sunflower seed Kernel was ranged betw-een 94.53% for vidok variety to 96.97% for Euroflor variety.
- The ash content varies in the range of 4.67% (on DB for Euroflor variety) and 5.80% (on DB for Hybrid, 102) with a mean of 4.74% (on DB).
- The highest value of oil content (51.24% on DB) was reco-rded in vidok variety. In contrast, the lowest value (42.48% on DB) was noticed in the kernel of Euroflor variety. On the other hand, it was observed the following values for protein content: 23.92, 29.69 and 14.64% (on DB) in Hy-brid (102), Euroflor and Vidok, respectively
- The following results were obtained for fiber content: Hy-brid –102 (16.17% on DB); Euroflor (15.48%) and Vidok (22.58).
- Concerning the carbohydrates content, the results indicated that the kernel of Euroflor variety had the highest value of carbohydrates (7.68% on DB) followed by Hybrid –102 (7.20%) and the lowest value (6.28%) was found in the kernel of Vidok variety.
1.3- Mineral content of sunflower seeds :-
It is noteworthy to mention that the sunflower seeds can be consider as a good source of minerals content and for this reason the sunflower meal can be used in animal nutrition as a good source for minerals.
Further more, the data of this investigation indicated the following:-
- The samples of Hyprid–102 (either whole seeds or kernel) had the highest value in minerals content (phosphor, potas- sium, magnisum, sodium, zink, cupper, iron and calcium) followed by samples of vidok and the lowest value in minerals content was found in Euroflor samples.
- Phosphorus content was ranged between 730 and 1900 mg /100g for achen and between 700 and 730 mg/100g for su- nflower seed kernel.
- Potassium element (K) represent the predominant inorgan-ic constituent in sunflower seeds either whole seeds or ker-nel.
- A linear relationship was observed between the minerals co-ntent in the whole seeds (achen) and minerals content in the kernel.
2 – Sunflower seed oil characteristics :-
2.1 – Physical properties and chemical characteristics ;-
The physical properties and chemical characteristics of sunflower oil samples extracted from different varieties and hybrids were determined. The results obtained herein indicated the following:
- The specific gravity at 25/25°C ranged between 0.9170 (Euroflor) and 0.9176 (Hybrid – 102) with an average 0.9173.
- The refractive index at 25°C were 1.4735; 1.4739 and 1.4732 for sunflower oil samples extracted from Euroflor, Vidok and Hybrid ( 102 ) ,respectively.
- The color of oil extracted from Vidok variety was darker th-an the color of the other oil samples.
- The acid value was in the range of 0.31 (in Euroflor variety) and 0.93 mg KOH /g. oil (in Hybrid – 102) with an average of 0.62 mg KOH/g. oil .
- The iodine value of sunflower oil samples under investigati-on were 114.13 ; 103.46 and 118.54 for Euroflor , Vidok and Hybrid (102) , respectively. - The high iodine value could be attributed to the higher content of linoleic and linolenic.
- The sunflower oil extracted from Euroflor variety gave the highest saponification value (192.00) while, the lowest val-ue (188.00) was recorded in sunflower oil sample extract-ed from Vidok variety.
- The peroxide values were 0.75; 1.15 and 1.23 meq. peroxi-de / Kg sample in Euroflor, Vidok and Hybrid (102), resp-ectively.
- The acid and peroxide values of all oil samples used in this study indicated that the oils are in a good quality and safe for dietary uses.
- The oil samples had comparable content of unsabonifiable matter (1.10%, 1.02% ,and 0.97% for oil samples extracted from Euroflor, Vidok and Hybrid (102), respectively.
2.2 – Fatty acid composition of sunflower oil :-
The data obtained by G.L.S. indicated that :
- The major fatty acids were oleic (37.40 - 48.58%) and linoleic (34.97 – 49.16%) followed by palmitic acid (7.84 – 9.53%), stearic acid (3.52 – 4.55%), arachidic acid (0.22 – 1.43 %), behenic acid (0.65 – 0.83% ) and linolenic acid (0.41- 0.45%).
- The amount of TSFA was ranged between 13.03 and 16.01 % while, The amount of TUFA ranged between 83.99 and 86.97%.
- Vidok variety contains the highest percentage of oleic acid (48.58%) while Euroflor variety contains the lowest perec-entage (41.52%)
- Hybrid (102) contains the highest percentage of linoleic acid (49.16%) while, Vidok variety contains the lowest pe-rcentage (34.97%).
- There were a little difference in amount of palmatic acid and stearic acid in the investigated oils.
- Small percentages of arachidic, behenic and linolenic acids were present in most varities and hybrids.
- Hybrid (102) contains the lowest percentage of TSFA (13.03%) while Vidok varitiey contains the highest percen-tage (16.01%). On the other hand, Vidok variety showed the lowest percentage of TUFA (83.99%) while, Hybrid (102) recorded the highest value (86.97%).
- A linear relationship between iodine value and linoleic acid content was recorded. At the same time, it was observed an invers relationship between oleic content and linoleic acid content.
- The high oil varieties of sunflower are characterized by a predominance of linoleic acid over oleic acid, increases in the oil content of the sunflower seed were accompained by increased in linoleic acid content.
2.3 – Unsaponifiable fractions of sunflower oil:-
The relative percentage of hydrocarbon and sterol comp-onents of oils under investigation were different according to seed variety or hybrid. The results obtained showed the following:-
- The percentage of hydrocarbon were found to be 21.41%, 30.51% and 47.04% of unsaponifiable matter for Euroflor, Vidok and Hybrid (102), respectively.
- Total sterol ranged from 52.96% to 78.59% of the unsapo-nifiable matter. Hybrid (102) contains the lowest percen-tage while Euroflor variety contains the highest percen-tage.
- β- sitosterol was the major sterol fraction of total sterol followed by stigmatsterol and compesterol.
- Hybrid (102) contains the lowest percentage of β- sitosterol (34.13%), while Euroflor variety contains the highest percentage (55.91%). The amount of stigmasterol was ranged from 12.80 % of the unsaponifiable matter (for Hybrid –102) to 16.30 % for Vidok variety.
- The value of compesterol was ranged from 6.03% of unsap-onifiable matter (for Hybrid –102) to 10.55% (for Vidok variety).
3 – Effect of refining processes on some charachteristic of sunfl-ower seed oil, fatty acid composition, tocopherols and phospholipids content:-
The results of this investigation led to the following conclusions:-
- The refining processes (degumming, neutralization, bleac-hing and deodorization) did not change or have any apprec-iable effect on the R.I. and Sp.Gr.
- The degumming process had effect on oil color i.e the color of degummed oil is lighter than the color of crude oil.
- The oil color was decreased after neutralization. The rate of color reduction depends on the initial color of oil befor neutralization, the nature of color pigments in oil and the neutralization conditions such as temperature and alkaline solution conditions.
- The bleaching operation, in general, leads to the diminution of oil color. The rate of decreasing the color depends on the oil color before bleaching, the type and proportion of bleaching substances and the bleaching time and temperature.
- The dorization process did not influence the color intensity of oil.
- On the basis of oil acidity, it was observed that the degum-ming process led to a slight increase in oil acidity. On the other hand, the oil acidity is greatly decreased by neutraliz-ation, the rate of decreasing being dependent on the initial acidity of oil before neutralization, as well as neutralization condition, such as temperature and NaOH concentration.
- The bleaching and deodorization operations led to sligh decrease in the oil acidity.
- As for as the effect of refining process on the iodine value (I.V.). The results showed no major changes occurred in I.V. due to refining processes.
- The fatty acid composition changed more or less slightly during refining and no marked changes was noticed. In general, the values of C16:0, C18:0, C18:1, C20:0 and TSFA were increased slightly. In contrast, the values of C18:2, C18:3, C22:0 and TUFA were decreased slightly. The major saturated fatty acid was palmitic acid while the major unsa-turated fatty acids was linoleic acid followed by oleic acid.
- The refining processes reduced the tocopherols content. The rate of reduction dependent on the initial content of tocop-herol as well as the refining processes condition. The redu-ction percentage in tocopherol content was ranged between 4.66% (in degummed oil) and 20.38% ( in deodorized oil). It is noteworthy to mention that although a little decrease in the content of tocopherols was recorded at almost every st-age of refining, the major decline in tocopherols content was at deodorization stage.
- The phospholipids content was decreased at almost every st-age of refining, the major decline was recorded at the degu-mming stage in comparison with crude oil.
4 – Effect of storage period at room temperature on some cha-racteristics and fatty acid composition of sunflower seed oil:-
- The R.I was decreased gradually as storage period increase. On the other hand, the results obtained showed a linear relationship between R.I and I.V.
- The storage of sunflower oil at room temperature for six months did not seem to have any appreciable effect on the Sp.Gr. of the investigation oil samples.
- The color intensity was increased during storage. The extent of increase was affected by storage period. The increase in color intensity of oil samples during storage could be attributed to the formation of fatty acid polymers which accumulate as a result of triglycerides hydrolysis during storage. The increase in color index is probably due to oxidation typically resulting in the ge-neration of hydroperoxides, conjugated dienoic acids, epoxides, hydroxides and ketones.
- The acid value (A.V.) increased gradually in oil samples during storage. However, the rate of increase was dependent on the storage period. Generally, it was observed that, the oil samples stored for six months had the highest increase in A.V. The slight gradual increase in the A.V. could be attributed to the hydrolysis of some phosphatides and triglycerides into glycerol and free fatty acids. Although the acid value is an index of hydrolytic rancidity, it was measured as acids contribute to the development of off-flavor and off-odor in the products.
- Oxidative rancidity is the principal problem in fats and oils. Per-oxid value (as indicator of primary oxidation) was employed in this study to determine the extent of oxidation caused during storage. The results of this investigation indicated that the peroxide value (P.V.) was increased graduallu in oil samples during storage. The gradual increase in P.V. could be attributed to the accelerating temperature in the presence of oxygen on oxidation and peroxide formation.
- The data of this investigation revealed that the degree of unsaturation, as measured by the iodine value (I.V.) showed a slight gradual decline during storage. The I.V. of oil sample at zero time of storage was 115.11, this value became 110.41 after six months of storage. The decrease in I.V. during storage could be explained on the basis of the double bonds saturation of the fatty acids during the production of hydroperoxides and intermediate compounds.
- The obtained results showed also that the decrease in the I.V. was accompained by the decrease in C18:2 content.
- The results of G.L.C. revealed that the values of fatty acids C16:0, C18:0, C18:1, C20:0, C22:0, TSFA and ratio of C18:1, C18:2, as well as ratio of TSFA : TUFA were increased with increasing the storage period. In contrast, the values of fatty acids C18:2 and C18:3 , as well as TUFA were decre-ased.
- The rate of change in fatty acid composition either increase or decrease was dependent on the storage period. The decrease in unsaturated fatty acid (especially C18:2 and C18:3) could be attributed to the oxidation and hence the change in the degree of unsaturation. It is noteworthy to mention that the decrease in linoleic and linolenic acid content was accompained by the decreased in the iodine value.