In this study, the drying behaviour of black olive slices using microwave was investigated and the effects of microwave power on total phenolic content and colour were determined. Black olive slices were dried at different power levels (180, 360, and 540 W) using a microwave cabin. The results showed that the drying time of the olive slices decreased considerably as the microwave power increased. The total phenolic content of the product dried at 540 W was found to be significantly lower than those dried at 180 or 360 W. For the microwave power range studied, the use of an irreversible first-order model adequately described the decrease in the total phenolic content. The effects of microwave power level on changes of the surface temperatures and weight loss of the olive slices were also determined. The temperature increase and the weight loss were the highest at 540 W during drying. Changes in the colour values (L*, a*, and b*) of the black olive slices during drying were statistically different (P<0.05) for each microwave power level and the maximum change in brightness occurred drying at 360 W. It is thought that results obtained in this study will provide valuable data for the design of microwave drying systems used for drying of olive slices in pilot or industrial scales.

In this study, different fiber sources such as inulin, peas and carrots were used to produce fruit snacks enriched with dietary fiber. The effect of these fiber sources on the proximate composition, pH, titratable acidity, water activity, color, texture, total phenolic content, microbial load, and sensory acceptability of fruit snacks was determined. Results showed that fruit snacks enriched with inulin (5.0%) had the highest content of total dietary fiber while snacks enriched with carrot fiber (5.0%) had the highest total phenolic content. The moisture content of fruit snacks with different fibers decreased in comparison to control snacks as fiber was added into their formulation. Moreover, the water activity values of fruit snacks (aw) were lower than 0.7, indicating a low risk for bacterial growth and affirming a favorable shelf life. Compared to control snacks, increasing the dietary fiber addition from 2.5 to 5.0% significantly increased the hardness, gumminess and chewiness values of fruit snacks. The microbiological analysis of fruit snacks indicated that snacks were safe. Additionally, results showed that fruit snacks (2.5%) enriched with inulin and pea fiber were found to have higher sensory acceptability scores than others.

Recently the demand for functional food components such as prebiotics, probiotics, and phenolic compounds are increased. Nowadays, β-glucan, dietary fiber, and biologically active natural polysaccharide, exhibit properties like a prebiotic effect and immune system support. Furthermore, clinical studies have shown that daily intake of 250-500 mg β-glucan has several benefits on the immune system, showing low glycemic index, antimicrobial and anti-inflammatory properties. It is a polysaccharide composed of D-glucose monomers connected with β-glycoside bonds, found in natural sources like yeast (Saccharomyces cerevisiae), some edible mushrooms, algae, and cereal grains. β-Glucan is more resistant and preserves its stability during food processing technologies (drying, freezing, etc.). Especially, β-glucan originated from baker's yeast (S. cerevisiae) has many immunostimulatory properties, such as hypoglycemic, anti-inflammatory, immune-modulatory, antioxidant, and anticancer activities. Also, the utilization of β-glucan in the food industry has increased regarding to their techno-functional properties like gelation, viscosity, solubility, and encapsulating agent. Therefore, this review highlights recently published research results on the functional properties, health benefits and clinical studies, the effects on the interaction with the other food compounds, and the potential food applications of β-glucans.