Determination of antidiabetic activity and in vitro bioavailability in white and whole wheat bread varieties added to the white mulberry (M Vİorus alba) leaves and pulp

Functional food science has been conducting various studies on product formulation designs that will ensure healthy, well-being as well as human nutrition. In order to prevent diabetes or to balance the level of blood sugar, the amount of sugar in the blood should be controlled. The use of natural inhibitors against carbohydrate digestive enzymes in the prevention of Type-2 Diabetes is seen as one of the treatment methods. In this thesis, white mulberry (Morus alba) pulp (10%) or white mulberry leaf (3%) were freeze-dried in lyophilizer and added to the breads in powder form. Total phenolic analysis, total antioxidant analysis and antidiabetic activity analyzes have been performed in raw materials and bread products. After in vitro digestion modeling, the bioavailability of phenolic compounds and antioxidant content have been determined.Evaluation of phenolic composition, gallic acid, catechin, epigallocatechin gallate, ferulic acid, p-coumaric acid amount of samples have been determined. Colour,texture and sensory analysis have been performed for the breads. Colour analysis showed no significant difference crust colour of bread products (p>0.05) but significant differences have been found in L*, a *, b * values of interior colors (p<0.05). Texture analysis has been performed using tissue profile analysis (TPA) for parameters of hardness, adhesiveness, springiness, cohesiveness, gumminess, chewiness and resilience The effect of enrichment of bread samples with pulp or leaves on texture parameters have been determined to be significant (p <0.05). In sensory analysis, ranking test has been performed for panelists. While the most popular bread control was whole wheat bread, the product which have not been preferred was reported as leafy white bread. According to sensory analysis results, after the whole wheat bread, the most have been preferred product as mulberry pulp white bread. The highest amount of phenolic content in the total amount of phenolic content of leafy whole wheat bread 48.26±5.40 mg/100 g GAE, the lowest amount of phenolic compound in control white bread 18.50±1.36 mg/100 g GAE has been determined. The differences in the phenolic content of the control group and enriched breads were significant (p<0.05). After in vitro digestion, ~ 2 times increase in phenolic content of all samples have been observed. The highest phenolic content after digestion in vitro was found to be leafy white bread with a value of 93.04±8.03 mg/100 g GAE.The effect of enrichment on the amount of phenolic substance after in vitro digestion has not been significant (p>0.05). When all bread products were evaluated, the product with the highest antioxidant activity was leafy whole wheat bread with a value of 3.29±0.33 µM TEAC/g. The effect of enrichment on the amount of antioxidant substance after in vitro digestion has been significant (p<0.05). According to the results of the antidiabetic activity analysis, the highest α-glycosidase enzyme inhibition has been 70.50±6.36% in leafy and white bread the lowest α-glycosidase enzyme inhibition 23.50±4.95% in control whole wheat bread. It has been observed that leafy breads had higher antidiabetic activity than pulp breads. The effect of enrichment of bread on α-glycosidase enzyme inhibition has been found to be significant (p<0.05). According to the results of the antidiabetic activity analysis, the highest α-amylase enzyme inhibition was 73.83±0.86% in leafy whole wheat bread and the lowest α-glycosidase enzyme inhibition was 20.89±1.20% in control white bread. The α-glycosidase and α-amylase enzyme inhibition values of acarbose used as positive control were 69.00% and 78.30%, respectively. Leafy whole wheat activity analysis was found close to the value of positive control acarbose. As a result of the thesis, it was concluded that the white mulberry leaf may be suitable for the purpose of seeking alternative natural inhibitors to the targeted antidiabetic drug. After in vitro digestion determined the highest values in leafy enriched bread, so the correlation have been verified phenolic matter and antioxidant activity between with antidiabetic activity. Keywords: polyphenols, functional bread, antidiabetic activity, in vitro bioaccessibility 2019, 112 pages