الفهرس 
INTRODUCTION
Health Benefits of SteviaOnly 14 pages are availabe for public view
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Abstract
As the predominant sweetener in the world, sucrose has a distinct in the human diet. Sucrose can contribute to an increased risk for chronic disease (e.g. hyperlipidemia, diabetes, dental caries and behavioral disorder). The one way to control the consumption of sucrose is to replace it by low digestible sweeteners as fructose, polyols or nonnutritive sweetener as stevia (natural nonnutritive sweetener). Stevia has been used in many countries as a sweetener due to its beneficial antihypertensive, antihyperglycemic, antioxidant, noncariogenic, chemoprotective, anti-inflammatory, immunomodulatory, and antiviral effects on human health. The absorption of polyols (sorbitol and mannitol) in our body is very slow and is incomplete.
There is incomplete metabolism of polyols and due to fermentive degradation, the products are short chain fatty acids and gases, so the energy absorbed is less as compared to energy absorbed in complete metabolism of polyols, resulting in lower blood glucose levels and lower insulin rises than with other carbohydrates. Fructose has replaced sucrose in many foods and beverages because of its sweetening power, lower cost, and functional properties that enhance flavor, color, and product stability. Due to this reasons people demand for sugar free products without compromising on calories is increasing day by day. Biscuits are of the most popular bakery product consumed nearly by all levels of society. This is mainly due to its ready to eat nature, good nutritional quality, and availability in different varieties, affordable cost and long shelf life. Fructose and sugar alcohols such as sorbitol and mannitol are used in special dietary foods as a bulking agent with sweet taste. Stevia sweeteners are heat stable to 2000 C, are acid stable and do not ferment, making them suitable for use in a wide range of products including baked/cooked foods.
Therefore the purpose of the present study is to investigate the effects of nutritive sweeteners as fructose, mannitol and sorbitol and nonnutritive sweeteners as stevia in the quality of biscuits.
The biscuits were manufactured on a semi-commercial scale, employing the recipe of Candy factory for sweets, biscuits and chocolate in Alexandria. Twenty five kilograms of biscuits (five kilograms for each sweetener) was processed using different treatments of sweeteners (280g sucrose, 150g fructose, 3g stevia, 400g mannitol and 400g sorbitol). All basic ingredients (wheat flour, sweeteners, shortening, dried milk, ammonium bicarbonates, sodium bicarbonates, sodium metabisulphate, salt, lecithin, vanilla, and water) were weighted accurately. All ingredients were mixed except flour and aerating chemical, mixing time from 15 min. The flour and aerating chemicals then added and mixed until dough acquires desired consistency. Dough produced on the table in progressive steps to a desired thickness. The desired shapes was cut out and was placed to the oven trays at a proper distance at 240⁰f in the baking oven for 20 min. after baking, the biscuits were cooled at room temperature and packed in glass boxes for determine the following measurements:
1.Physical analysis which includes width (cm), thickness (cm) and spread factor (cm)
2.Chemical analysis which includes moisture %, crude protein %, crude fat %, ash content %.
3.Sensory evaluation analysis which includes color, taste, odour, texture and after taste at different intervals of storage (e.g. 0, 30, 60 and 90 days).
4Rancidity degree analysis includes peroxide, acid, iodine and para anisidine value after 90 days of storage.
5.Calorific value calculation.
6.Statistical analysis.
Our study showed the following results:
1.Treating biscuits with mannitol resulted in lowering the mean value of width 4.43 cm than the mean value of sucrose 5.10 cm. Different types of treatments was statistically significant on the mean value of width (cm), while no significant change was observed in the mean value of thickness (cm) and spread factor (cm). Treated biscuits with fructose and sucrose showed decrease on the mean value (0.40 cm) of thickness, while treating biscuits with sorbitol showed decrease on the mean value 9.71 cm of spread factor.
2.The chemical analysis of biscuits treated with sucrose, fructose, stevia, mannitol and sorbitol was statistically insignificant. The highest decrease on the mean value of moisture and ash content as follow 3.17 and 0.60%, respectively was recorded in biscuits treated with sucrose, while stevia replacement showed the mean value (16.90 %) in crude fat but sorbitol have the lowest mean value (6.62 %) in crude protein content. Fructose treatment showed the lowest mean value (70.03%) of carbohydrates content.
3.The sensory evaluation analysis revealed that the storage period of 30, 60 and 90 days affect significantly all treatments of biscuits on the mean score of color, taste, texture and after taste, while affect insignificantly on the mean score of odor only in 90 days of storage. Treating biscuits with sucrose showed the best mean score of sensory evaluation from 0 to 30 days of storage, while fructose treatment showed the worst mean score of taste and odor was 2.8 after 90 days of storage, while 2.7 in texture after 30 days of storage. The worst mean score 3.0 and 3.1, respectively of color and after taste was recorded in biscuits treated with mannitol after 60 days and stevia after 90 days of storage.
4.The rancidity degree in regard to peroxide, acid, iodine and para anisidine values showed significant differences in all biscuits treatments after 90 days of storage. Peroxide value did not detect in fresh (0 days) biscuits treatments. After 90 days of storage the biscuits treated with fructose showed the lowest mean of peroxide, acid, iodine and para anisidine values as 2.40 meq oxygen/ 100g, 4.88 mg KOH/g, 55.78 mg I2/g and 7.07 mg/kg, respectively, while the biscuits treated with mannitol showed the highest mean of peroxide, iodine and para anisidine values as 10.00 meq oxygen/100g, 111.83 mgI2/g and 9.67 mg/kg, respectively. The highest mean value of acid was 9.52 mg KOH/g in biscuits treated with stevia.5.The replacement of sucrose with fructose, stevia, mannitol and sorbitol showed decrement in calorific value Kcal/100g in biscuits but insignificantly. Treating biscuits with stevia gave the highest decrease in the mean of calorific value as 462.43 Kcal/100g followed by sorbitol treatment (464.32 Kcal/100g) > mannitol treatment (464.99 Kcal/100g) > fructose treatment (466.01 Kcal/100g) > sucrose treatment (473.49 Kcal/100g).
It could be concluded from our results that:
Replacement of sucrose with fructose, stevia, mannitol and sorbitol can affect the physical, chemical, sensory evaluation characteristics, calorific value and rancidity degree of biscuits manufactory.
The replacement of sucrose with fructose, stevia, mannitol and sorbitol affect significantly on the mean value of width (cm), while affect insignificantly on the mean value of thickness (cm) and spread factor (cm).
Treating biscuits with sucrose, fructose, stevia, mannitol and sorbitol did not affect significantly on the chemical analysis of biscuits as regard to moisture%, crude protein%, crude fat% and ash content% and carbohydrates %.
Replacing sucrose with sorbitol in biscuits did not affect significantly sensory evaluation characteristics at different time of storage.
Storage period of 30, 60 and 90 days affect significantly all treatments of biscuits on the mean score of color, taste, texture and after taste, while affect insignificantly on the mean score of odor only in 90 days of storage.
Storage period of six months affect significantly on the rancidity degree as regard to peroxide, acid, iodine and para anisidine values in biscuits treated with sucrose, fructose, stevia, mannitol and sorbitol.
The replacement of sucrose with stevia gave less good quality biscuits in regard to after taste, while gave good biscuits in regard to calorific value.
Replacement of sucrose by sorbitol gave good quality biscuits, while treatment of mannitol gave bad quality biscuits as regard to odor.
Treated biscuits with fructose increase its shelf life due to its lower response to rancidity, while treating biscuits with mannitol gave the highest response to rancidity.
from the results of this study, we were able to come to the following recommendations:
1.Consumer should shift from using sucrose to low digestible sweeteners (fructose, mannitol and sorbitol) or the nonnutritive sweetener (stevia as a natural sweetener) due to its adverse health effects.
2.Stevia plant should be cultivated in a large scale and be approved as sweetener in food products to reduce the calories intake from sugars.
3.Sorbitol should be used in the manufacture of many food products due to its functional benefits offering to foods other than sweetness.
4.Fructose can be used to extending shelf life of biscuits, while mannitol was not recommended in this case.
5.Storage of biscuits should not exceed 60 days.
6.Sensory evaluation on products is recommended.
7.Further studies are needed to illustrate the effect of storage on biscuits.