İncir, ayva ve kayısı tozlarında teknik ve duyusal özellikler, antioksidan aktivite ve fenoliklerin biyoerişilebilirliğinin değerlendirilmesi

Today, fruit consumption has received great attention due to its positive effects on health, especially its rich polyphenol content and antioxidant activities. Fig, quince and apricot important crops worldwide are rich in minerals, vitamins and fiber content. Our country is first in the production of these three fruits. Processed products such as jam, marmalade and fruit leather are also produced from these fruits which are consumed fresh or dried. They also have the potential to be used as an additives in the form of fruit powder and fruit tablets in the food, cosmetic and pharmaceutical industries. Fruit powders and fruit tablets are resistant to microbiological deterioration due to their low moisture content, as well as the consumption, handling / storage and easiness of standardizing product dosage. The aim of this doctoral thesis is (I) to determine the physico-chemical, techno-functional and sensory properties of figs, quince and apricot powders or tablets which are developed as value added product, (II) to compare the total phenolics, total flavonoids and antioxidant activities of fresh, dried and powdered samples prepared individually or in combination, (III) to assess their bioaccessibility by using in vitro gastric and small intestinal digestion simulation. Experiments were carried out in 4 stages to achieve these goals. First, the fruits were dried and grinded to powder; fruit tablets were also produced from fruit powders. Then, physico-chemical properties (moisture content, ash content, color properties, water activity), techno-functional properties (oil holding capacity, water holding capacity, wettability, solubility, density and flowability) were measured by basic chemical methods. In sensory analyzes, the panelists were asked their opinions about appearance, flavor and general acceptability of fruit powders mixed with yogurt, honey or milk. Then, total phenolics, total flavonoids and antioxidant activities of fresh, dried and powdered samples prepared individually or in combination were determined by spectrophotometric methods. Finally, antioxidant activity and the bioaccessibility of phenolic compounds and flavonoid compounds after in vitro digestion simulation were analyzed using the procedures gastrointestinal dialysis membrane. The most remarkable techno-functional properties obtained due to the physico-chemical properties of the products were determined that fig powder had the highest porosity, quince powder had the highest water holding capacity and apricot powder had the highest oil holding capacity. It was observed that the flow properties of apricot and fig powders were close to each other and were better than quince powder. In terms of density, quince fruit was found to be more suitable for use in powder form than the other two fruits. In terms of all sensory properties except the appearance of honey, quince powder had the highest scores compared to other fruit powders. Quince powder appearance in yogurt, taste feature in honey, general acceptability feature yoghurt was the highest output. In addition, sensory analysis was performed on the fruit tablets, and the results showed that the most suitable fruit for the tableting process was the apricot tablet with the highest flavor and highest flavor densities and the appropriate tissue profile. In the fresh fruit form, total phenolic compounds were found to be higher than the other two forms, ie dried fruit and fruit powder. Similarly, total antioxidant activity values were highest in fruit form and total flavonoid values were highest in dried form. In this study, if the samples were consumed together, the synergistic effect that may occur during the absorption of phenolic compounds from the intestine was investigated and the recovery rates were calculated. It was observed that the total phenolic compound recovery values of all mixtures (apricot dry + quince dry (94%), fig powder + apricot powder + quince powder (95%) except) were high, ie the combined consumption had a synergistic effect. Similarly, when the antioxidant activity recovery values of the mixtures were examined, a significant decrease was observed in all fruit samples, but it was observed that fruit powder and dried fruit mixture samples (except fig dried + apricot dried (61%)) had higher antioxidant activity than the fruits alone. As a result of this thesis, techno-functional and sensory analysis showed that quince fruit is more suitable for use in powder form and apricot fruit is more suitable for use in tablet form. In addition, fruit powder production process caused loss of total phenolics and total flavonoids bioaccessibility and total antioxidant activity values of fresh fruits, but fruit powders mostly had close bioaccessibility value with dried fruits. Additionaly, it was observed that together consumption of fruits (in dried form or powdered form but not in fresh form) had a synergistic effect on bioaccessibility of phenolics and total antioxidant activity value.