Simulated gastrointestinal digestion and storage stability of tomato waste encapsulates

Abstract

The application of bioactive antioxidant compounds is limited because of their instability. To overcome this drawback, different protection systems including encapsulation have been developed. In this study, for the stabilisation of bioactive compounds (carotenoids and phenolics) extracted from tomato waste, encapsulation with carbohydrate (inulin and gum arabica) and protein (soy protein and pea protein) wall materials by freeze drying method was applied. Content of bioactive compounds and antioxidant properties (determined by DPPH, reducing power and β-carotene bleaching assay) of encapsulates before and after in vitro digestion was investigated. Also, in obtained encapsulates carotenoid stability during storage at ambient (25 ± 5 °C) light and dark conditions for four weeks was assessed. The results indicated that release behavior of bioactive compounds and antioxidant activity after digestion of encapsulates varied according to the type of wall material. Protein carriers showed better ability to preserve phenolic compounds through in vitro gastrointestinal digestion in comparison to carbohydrate wall materials. Pea protein showed best carrier properties for delivery of carotenoids, while differently to other used carriers, gum arabica showed minor ability to release carotenoids after in vitro gastrointestinal digestion. During storage higher content of carotenoids was preserved in encapsulates prepared with carbohydrate carriers. All encapsulates retained higher amount of carotenoids under dark conditions. The results of this study showed that assessment of the behavior of encapsulates during digestion and storage is necessary in order of selection appropriate delivery system of bioactive compounds in powder form which can be used as ingredient in functional food products.

Keywords

• tomato waste
• bioactive compounds
• encapsulation
• gastrointestinal digestion
• stability study