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Abstract Part I: Physicochemical properties and hypolipidemic activity of polysaccharides solutions 1. Physicochemical properties of ethanol precipitated flaxseed or cress seed mucilages compared with commercial guar gum The flaxseed (FSM) and cress seed mucilages (CSM) were extracted, ethanol precipitated and dried in a hot air oven at 60°C over night. The dried ethanol precipitated FSM and CSM as well as commercial guar gum (GG) were dissolved in distilled water to make the 1.0% (w/w) polysaccharides solutions. The solutions were kept at 5±2°C overnight to achieve complete hydration. The physicochemical properties of ethanol precipitated FSM and CSM compared with commercial GG were evaluated. The results could be summarized as follows: - The yield of ethanol mucilage extracted from flaxseed and cress seed was 10.22 and 7.29%, respectively. Moisture, proteins and ash contents were lower in dried FSM than in dried CSM. - The clarity of polysaccharides solutions followed the trend: GG > CSM > FSM, the difference was significant. The lightness degree of both FSM and CSM solutions was significantly higher than that of GG solution. The redness and yellowish degrees were lower in both FSM and CSM solutions than in GG solution. - The foaming capacity of both FSM and CSM solutions was higher than that of GG solution. However, the foaming stability was the least in CSM solution. - The water holding capacity (WHC) of starch gel increased as a GG, FSM or CSM concentration increased until the concentration of 0.4, 0.6 or 0.4%, respectively. There was no significant difference in WHC of starch gel containing GG, FSM or CSM at the same concentration except at 0.4%, the WHC was the lowest in starch gel containing FSM. - All polysaccharides solutions exert shear-thinning behavior (apparent viscosity decreased as a shear rate increased), which was more pronounced in GG solution. The apparent viscosity was higher in GG solution than in both FSM and CSM solutions, higher in FSM solution than in CSM solution. - The antioxidant capacity of polysaccharides solutions was influenced by the source of polysaccharides. The antioxidant capacity of the CSM solution was the highest (25.43±0.6%), while that of GG solution was the lowest (8.75±0.4%). 2. Health effects of ethanol precipitated flaxseed or cress seed mucilages on rat fed a high-fat diet The study was designed to investigate the hypolipidemic effect of both FSM and CSM as compared to a standard lipid lowering drug (ATOR10®). Animals were subdivided into five groups (10 rats/group); (1) control healthy animals, (2) animals fed a high-fat diet for 8 weeks, (3) animals fed a high-fat diet for consecutive 8 weeks then orally treated daily with (10 mg/kg b.w) standard hypolipidemic drug (ATOR10®) for one month, (4) animals fed a high-fat diet followed by daily oral administration of FSM (40 mg/kg b.w) for one month and finally (5) animals fed a high-fat diet followed by oral administration of CSM (40 mg/kg b.w) for one month. The results obtained could be summarized as follows: - Rats fed a high fat died resulted in significant elevations in the serum glucose (8.7%), triglycerides (31.7%), total cholesterol (24.6%) and LDL-cholesterol (53.7%) and hepatic MDA (26.5%), matched with marked decrease in the serum HDL (- 17.4%) level and hepatic total antioxidant capacity (-22.4%) as compared to normal healthy animals. No marked changes were noticed in serum levels of AST, ALT, urea and creatinine. - In comparison to hyperlipidemic animals, the treated hyperlipidemic rats with ATOR10®, FSM or CSM, induced an insignificant change in the serum glucose (1.5, -5.39 & -4.25%) and significant reduction in triglycerides (-20.82, -8.79 & - 16.41%), total cholesterol (-19.10, -10.11 & -13.71%) and LDLcholesterol (-31.22, -18.30 & -24.99%) and hepatic MDA (-20.63, -8.68 & -15.48%) those were close to normal levels, matched with marked improvement in the levels of serum HDL (12.21, 8.08 & 4.61%) and hepatic total antioxidant capacity (21, 13 & 18%) respectively. Moreover, serum levels of AST, ALT, urea and creatinine still within its normal values. - In brief, the dislipidemic effect of both FSM and CSM was very evident. In comparison to standard pharmaceutical drug (ATOR10®), CSM performed a stronger dislipidemic potential than that of FSM one. - Based on the marked hypolipidemic effect, besides to their safety monitored from non toxic symptoms in both liver and kidney functions of the animals orally administrated with either mucilages (monitored from the unchanged serum AST and ALT activities as well as serum urea and creatinine levels), it could be recommended that CSM could be used in hyperlipidemea management, especially in pathological status. Part II: Physicochemical, microbiological and sensory properties of set-yoghurt containing ethanol precipitated flaxseed or cress seed mucilages, or commercial guar gum The dried ethanol precipitated FSM and CSM as well as commercial GG were added separately to standardized buffalo’s milk (~ 3.2% fat and ~ 15.0% TS) at rate of 0.025%, 0.05% and 0.10% but GG was added at the rate of 0.025% and 0.05% to create 8 treatments. The latter batch had no CSM, FSM or GG, serve as a control (C). The changes in physicochemical properties of yoghurt containing FSM, CSM or GG compared with plain yoghurt during storage at 5 ± 2 °C for 15 days were studied. The results could be summarized as follows: - Addition of different levels of GG, FSM or CSM had no significant effect on both pH value and WSN/TN ratio of resultant yoghurt throughout storage period as compared with plain set yoghurt. - Addition of different levels of GG, FSM or CSM had adverse effect on flavor compounds concentrations (acetaldehyde and diacetyl) compared with control yoghurt. Also, the concentration of acetaldehyde gradually decreased, while diacetyl gradually increased as the time of storage increase. - Slight improvement in the counts of Str. thermophilus and Lb. bulgaricus and Lb. acidophilus were observed as affected by addition of polysaccharides. - Yoghurt samples containing different levels of CSM or 0.025% GG exhibited lower wheying-off and whey syneresis compared with control yoghurt. A similar, addition of different levels of FSM reduced wheying-off properties, but had no effect on whey syneresis of resultant yoghurt. - No much difference was observed in the firmness of yoghurt containing different polysaccharides. Over storage period, the yoghurts showed continued increase in firmness of yoghurt containing 0.025 or 0.05% FSM from day 5 onward, whereas for both yoghurt containing CSM and 0.025% GG the increase was observed from day 10. However, yoghurt containing 0.05% GG exhibited lower firmness as compared with other yoghurt samples. - In general, all yoghurt containing different polysaccharides exhibited higher viscosity than plain set yoghurt. However, yoghurt containing 0.025% and 0.05% CSM or 0.05% GG showed continued increase in apparent viscosity until day 10 while for yoghurt containing 0.10% CSM, the increase was observed until day 5 and decline thereafter. Concerning to FSM, apparent viscosity of yoghurt containing 0.025% FSM was the highest as compared with other yoghurt samples. - Finally, addition of 0.025% GG, or 0.025 and 0.05% CSM, or FSM improved appearance (less wheying-off), body & texture (soft body and homogenous as well as smoother texture) and flavor of yoghurt, especially during storage. However, plain set yoghurt and yoghurt containing 0.05% GG and 0.1% CSM or FSM had the least sensory scores. Part III: Physical and sensory properties of ice cream containing ethanol precipitated flaxseed or cress seed mucilages, or commercial guar gum Ten treatments of ice cream mixes consisted of 10.0% milk fat (fresh cream) 11.5% milk solids not fat (fresh buffalo’s skim milk and skim milk powder) and 15.0% sucrose. The FSM, CSM and GG were added separately at the rates of 0.025, 0.05 and 0.10% (w/w), to create 9 treatments. The latter had no polysaccharides, which served as a control. All components were added to fresh buffalo’s skim milk slowly, dissolved, homogenized and aged overnight at 5±2°C. The physical and sensory properties of both mixtures and resultant ice cream were evaluated.The results could be summarized as follows: - The polysaccharide types and concentrations had no significant effect (P > 0.05) on the pH value, acidity percentage and surface tension of ice cream mixes as compared with control mix. - Ice cream mix containing 0.025% GG or CSM had the highest protein load in comparison with other ice cream mixtures. However, protein load in ice cream mix decreased, as GG or CSM concentration increased. Slight increase in protein load in mix containing different concentration of FSM was observed and the increase was not significant. - The mix viscosity and shear thinning behavior increased by increasing the proportion of GG, FSM and CSM in ice cream mixtures. Ice cream mix containing 0.1% FSM exhibited the highest viscosity followed by that containing 0.1% CSM and 0.05% GG, respectively. - The control mix and that containing 0.025% FSM or CSM followed by that containing 0.05% FSM showed the highest whipping ability after 5 min. The ice cream mix containing GG exhibited lower whipping ability than FSM and CSM at the same concentrations. - The addition of 0.025% FSM or CSM increased the overrun percentage as compared to overrun of control ice cream. At higher concentrations, addition of 0.05 or 0.10% FSM or CSM% had no significant effect on the overrun percentage; addition of 0.05% GG had adverse effect on the overrun of resultant ice cream as compared with control ice cream. - As a concentration of GG, FSM or CSM increased, the hardness of resultant ice cream decreased as compared with control ice cream.After 10 min, ice cream containing 0.025 CSM had the least melted ice cream. Thereafter, the amount of melted ice cream was lower in that containing 0.025% CSM, 0.05% GG or 0.1% FSM compared with control ice cream. - Slight improvement in both melting quality and body & texture of all frozen ice cream containing GG, FSM or CSM was observed. Also, frozen ice cream containing 0.05% GG or 0.025% CSM gained the highest score, which characterized with more smoothness and creaminess compared with that of other treatments. from the foregoing results, it can be concluded that the functional properties of polysaccharides in the liquids depend on the source of polysaccharides and type of ingredients as well as polysaccharides concentrations. For example, GG solution (1% w/w) exhibited higher apparent viscosity followed by FSM and CSM solutions. However, no much difference was observed in ice cream mix containing 0.025 or 0.05% GG, FSM or CSM; whereas the apparent viscosity of ice cream mixes containing 0.1% FSM was the highest. Both CSM and FSM exhibited anti-hypercholesterolemic and glucose metabolism controlling effects, and did not induce toxic effects in both liver and kidney functions of the male rats orally administrated with either mucilages. In yoghurt as fermented milk, the addition of 0.05% FSM and CSM was sufficient to improve the quality of set-yoghurt during storage period at 5± 2°C for 15 days, while addition of GG must be no more than 0.025%. In ice cream, addition of 0.025% FSM, CSM or 0.05% commercial GG was the best percentage to improve the physical and sensorial properties of resultant ice cream. |