Clitoria ternatea petal flower extract and its encapsulation : a study of bioactivity, digestive stability and bioaccessibility for food applications

Abstract

There has been a growing interest in active compounds of edible plants due to their possible health benefits. Clitoria ternatea (CT) flowers are one of favorable edible plants enriched phenolic compounds that possess a wide range of biological effects including antioxidants and diabetes. Nevertheless, there are no data available on the stability of CT extract after gastrointestinal (GI) digestion as well as the food additive application. The aim of the study was to investigate the stability and biological activity of CT extract after gastrointestinal digestion together with the development of microencapsulation of CT extract. Finally, the efficacy of CT extract on the protection of curtailing lipid and protein oxidation in cooked pork patties was evaluated. The results showed that CT extract after enzymatic hydrolysis of GI digestion increased total phenolic compounds and antioxidant activity concomitant with an increase in intestinal α-glucosidase (maltase and sucrase) and pancreatic α-amylase inhibitory activities as well as binding to bile acids. Moreover, CT extract delayed glucose absorption by inhibiting glucose uptake through sodium-glucose cotransporter-1 (SGLT1) in Caco-2 cell line. Interestingly, the degradation of total phenolic compounds of CT extract was observed at gastric phase of digestion. In order to protect the degradation, the optimized condition of CT-loaded alginate microencapsulation was developed, comprising of 10% CT, 1.5% alginate, and 3% CaCl2 (w/v). The microencapsulation of CT provides good characteristics including a high percentage of encapsulation efficiency (84.83±0.40%), narrow size distribution (985 µm), spherical shape with smooth surface, desirable thermal stability (188°C) without a chemical interaction between the materials and CT extract. Interestingly, the microencapsulation of CT significantly retained higher amount of polyphenols and improved antioxidant and pancreatic α-amylase inhibitory activity as well as bile acid binding after the GI digestion. In the roles of food additive in meat products, CT extract (0.08–0.16%) exhibited potent radical scavenging activity and retarded lipid and protein oxidation during refrigerated storage together with acceptable sensory characteristics in cooked pork patties. Therefore, CT extract and its microencapsulation could be considered as a potential source of bioactive ingredients for functional food industry.