الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
 |  | from | 144 |  |  |
| | | from | 144 | | |
Abstract
S. elaeagnifolium is a deep-rooted perennial herb with acicular spines on the stems and leaf ribs. Leaves are dark green to pale grayish green and its flowers are blue, violet, or rarely white. The fruit, initially spherical and green (with white patches) and fleshy, becomes yellow to orange at maturity. A single plant generally produces 40 to 60 fruits, each containing 60 to 120 seeds. S. elaeagnifolium has numerous common names including Silverleaf nightshade, White horsenettle, Bullnettle, meloncillo and Orevienta caballo.
No research work appears to have been carried out on the use of milk clotting from fruit seeds of S. elaeagnifolium plant in Ras cheese making. Therefore, the present investigation was planned to assess information on the clotting, acceleration, quality and ripening changes of Ras cheese made from fruit seeds of S. elaeagnifolium plant - treated buffalos milk.
1- Extraction of fruits seeds of S. elaeagnifolium plant with 0.1 M sodium phosphate buffer pH 5.9 gave the highest ratio Sp. clotting activity/Sp. PA (73.04) compared to Sp. clotting activity/Sp. PA of distilled water pH 6.8 (59.34), 0.1 M acetate pH 5.6 (56.06) and the lowest 0.1 M citrate pH 5.6 (45.26).
2- The results showed that, the crude MCE using (5gm/30 ml) gave the highest MCA (19.21 IU/ml), total activity (950.5 IU/ml), Specific activity (914.46), yield (100 %) and Rate purification (1.00).
3- The partially purified MCE using different ammonium sulphate concentration (0–90 % saturation). The results showed that, 30–50 % saturation gave the highest MCA (81.11 IU/ml), total activity (811.1 IU/ml), Specific activity (1622.2), yield (84.44%) and Rate purification (1.77) accordingly; the range of 30-50 % was selected for potential purification of the MCE and proteolytic enzyme for fruits seed of S. elaeagnifolium plant.
4- The partially purified MCE was ion exchange chromatography on DEAE-Sepharose. The protein was then adsorbed on DEAE- Spharose chromatography column, and the highest MCA was eluted at 0.3 M NaCl in fractions (30–35), specific activity was increased to (1964.5) and (2.15) rate purification, and about yield of (11.24 %) of its activity was recovered
5- The partially purified MCE was chromatographed in a column of Sephadex G-100 and the purification showed only one peak. Purification results of the enzyme from S. elaeagnifolium fruit seeds using different purification means resulted in (2.52) rate purification with a yield of (6.002 %) and specific activity of (2306).
6- The partially purified enzyme was chromatographed in a column of Sephadex G-200 purification results of the enzyme from S. elaeagnifolium fruit seeds using different purification means resulted in (4.21) rate purification with a yield of (4.008 %) and specific activity of (3850.0) A simple purification procedure was developed in this study to obtain a very active and stable enzyme from S. elaeagnifolium fruit seeds.
7- The molecular mass of the purified enzyme was calculated as 28 kDa, which coincided with the band of bovine serum albumin.
8- pH of enzyme retains its activity in the pH range of 4.0 to 6.5, and the highest MCA of S. elaeagnifolium fruit seeds was observed at pH 5.9 and the proteolytic retains its activity towards denatured casein in the pH range of 6.0 to 9.0 , and highest PA at pH 8.
9- The results showed that effect of different temperatures from 10 to 100 °C on MCA and PA of S. elaeagnifolium fruit seeds. The highest MCA of our purified MCE was at 40 oC. The highest PA at temperature 50 oC.
10- The thermal stability to enzyme was incubated on the temperatures from 40-85 °C for (10-60 min). The enzyme activity is stable at from 40 to 60 °C on the incubation times from (10-30 min) and then slight reduced in enzyme activity on times of the (40-60 min).
11- CaCl2 was added in different concentrations from 1-50 mM. Indicated that increasing the concentration of CaCl2 with increasing clotting activity and PA even 20 and 10 mM CaCl2 respectively.
12- Used different concentrations of NaCl from 0 -16 % on the purified MCA and PA. Indicated that increasing the concentration of NaCl with increasing clotting activity and PA even 2 % and 1 % NaCl respectively.
13- The results showed some metal ions and other materials was added in different concentrations (1 and 5 mM) found that, at (1 mM) Zn2+,Ba2+, EDTA, Mg2+, Mn2+ are activators, whereas Fe2+, Mg3+,Ni2+ are inhibitors of the purified MCA. The Cu2+ at 1 mM was the most effective, and found that, at (5 mM) Ba2+ are activator, whereas Zn2+, EDTA, Mg2+, Cu2+, Mn2+, Fe2+, Mg3+, Ni2+ are inhibitors, The Mg3+, Ni2+ at 5 mM were the most inhibitors of the purified MCA.
14- The results showed Misallies constant as determined by double reciprocal plot was found to be 0.0399 %.
15- The results showed the effect of clotting activity by different concentrations of purified MCE namely 0.025, 0.05, 0.1, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45 and 0.5 (ml enzyme/2ml skim milk), it can be deduced that there was a parallel relationship existed between the enzyme concentration and MCA. There was a change in the coagulation parameters with the concentration of enzyme.
16- The enzyme activity was determined. About 90.39 % and 75.39 still retained of activity was observed for planet MCE after being kept 15 days at refrigerator temperature and the room temperature respectively.
PART II: ACCELERATION OF RAS CHEESE MADE from BUFFALO’S MILK WITH DIFFERENT COAGULANTS
Three Ras cheese treatments were made from buffalo’s milk.
- All cheese treatments mad with traditional cheese starters (Lactococcus lactis spp lactis and Lactococcus lactis spp cremoris, 1:1)
- The first was a control one being made with Ras cheese microbial ren net.
- T1 was made by using the Veal rennet.
- T2 made by using the purified rennet from S. elaeagnifolium fruit seeds. selected from the first part.
All cheeses were stored at 14 ºC for 120 days for ripening, and were examined periodically for some chemical, textural profile analysis and organoleptical properties.
1- The results showed the effect of rennet on the MCA and PA. Microbial rennet gave the highest ratio Sp. clotting activity/Sp. PA (147.75) compared to that of Veal rennet and purified plant extraction.
2- Results showed the moisture content at zero time Ras cheeses were 42.05, 41.34, and 41.72 % for control, T1, and T2 cheeses, respectively. The results indicated that control treatment had the highest moisture content. While, Ras cheese treatments with different coagulants had lower moisture content being the lowest in T2 made with purified plant rennet. The moisture contents after 4 month of storage were 34.68, 34.20 and 33.95 % for control, TI, and T2 cheeses, in order, the changes occurred in moisture content of treatments during ripening period could be due to the acidity development, which helps to increase the PA.
3- The obtained data also indicate that Ras cheese made with T2 had the highest TA while, followed by the control cheese and T1 had the lowest TA, when zero time and along ripening period. This could be due to the production of acidic compounds as a result of fermentation of residual lactose.
4- Generally, obtained results indicated that Ras cheese T1 contained no significant (p < 0.01) TN, SN, NPN ratio, while the T2 was the highest, followed by control treatment during ripening period.
5- The results showed that cheeses of T1 contained lower soluble tyrosine and soluble tryptophan ratio than in the other cheese treatments made with the different coagulants. After 4 months of ripening, there was significant (p < 0.01) difference between all treatments for tyrosine and tryptophan.
6- Obtained results indicated that, the rate of accumulation of TVFA increased with the increase of the ripening period in all cheese treatments. Values of TVFA in the cheese samples on zero time were 12.50, 10.66 and 11.66 ml of cheese for control. TI and T2 cheeses, it could be noticed that among treatments, control possessed the highest value of TVFA while T1 had the lowest. Furthermore, control and T2 showed highly significant (p<0.01) difference in TVFA than T1 cheese.
7- Obtained results indicated that, the rate of accumulation of NaCl percentage increased with the increase of the ripening period in all cheese treatments. NaCl percentage in the cheese samples on zero time were 2.04, 2.16 and 2.28 % for control. TI and T2 cheeses, in order. The corresponding values for ripening cheese after 120 days were 2.9, 3.01 and 3.33 % for same treatments in the same order. from these data, it could be noticed that among treatments, T2 possessed the highest percentage of NaCl while control had the lowest.
8- The obtained results revealed that total BAs in T1 treatment was very high, which may be harmful to consumers. Conversely, the T2 contain very low levels of total BAs and do not contain the harmful histamine or Tyramine, unlike the other treatments, followed by control treatment, rendering Ras cheese safe for human consumption.
9- The results showed estimate textural profile analysis (Hardness, Cohesiveness, Springiness, Gumminess, Chewiness) of Ras cheese treated with different coagulants during ripening at (0, 45, 90,120 days), the control treatment was found to have the best texture profiles than the other treatments.
10- The results showed in all cases the acceptability increased during the early stage of the storage and by extending the ripening period. The improvements were slow in T1 treatments while; it was faster in the other treatments, being faster in T2 with plant extraction from S. elaeagnifolium seeds. Stored cheese samples of T2 gained the highest significant (p<0.01) score at the 3 month to properties accept similarity the control treatment at 4 month in end ripening period
11- It could be concluded that for the fast Ras cheeses consumption, used of purified plant extraction from S. elaeagnifolium fruits, can be recommended to acceleration of Ras cheese ripening. As it has a noticeable effect on the quality and acceleration ripening of this type of cheese.