Vegetable matrices contain secondary metabolites that play important biological roles. Red fruits have been highlighted among the most consumed vegetable matrices because of their interesting bioactive content and sensorial attributes (Bortolini et al., 2022a; Ribeiro et al., 2019a; Rossetto, Maciel, Bortolini, Ribeiro, & Haminiuk, 2020). However, edible flowers are not much exploited although their high potential for improving nutritional, functional, and sensorial properties in traditional culinary arts (Bortolini et al., 2022b; Yang & Shin, 2017).

Among the bioactive compounds, phenolic compounds stand out due to their antioxidant activity (Ma et al., 2018; Yang & Shin, 2017). This activity allows these molecules to interrupt the propagation of free radicals that become harmful when in excess. Due to this characteristic, the regular consumption of foods containing phenolic compounds reduces the risk of developing several diseases, including cancer and metabolic syndrome (Jiménez et al., 2016; Udani, Singh, Singh, & Barrett, 2011; Zhang, Wang, Xing, & Zhang, 2022).

Nevertheless, gastrointestinal digestion can affect the bioaccessibility of these compounds, that is, the amount viable for intestinal absorption. The reactions involved in gastrointestinal digestion can form different compounds with different biological activities (Jilani, Cilla, Barberá, & Hamdi, 2016). Due to the sensitivity of some phenolic compounds to gastrointestinal digestion, there is a demand for technologies for their preservation to increase their bioaccessibility (Ribeiro et al., 2019b).

Sodium alginate is a low-cost, biocompatible, biodegradable, and generally recognized as safe (GRAS) material extracted from algae, composed of (1–4) -linked β-D-mannuronic acid (M-blocks) and α-L- guluronic acid (G-blocks). This material can react with calcium chloride, where G-blocks bind calcium ions (cross-link agents), forming the calcium alginate polymer (Bennacef, Desobry-Banon, Probst, & Desobry, 2021; Tsai, Chiang, Kitamura, Kokawa, & Islam, 2017). Calcium alginate can be used as an encapsulating agent for different matrices such as microorganisms (Strobel et al., 2018), enzymes (Lassouane, Aït-Amar, Amrani, & Rodriguez-Couto, 2019), vitamins (Danarto, Rochmadi, & Budhijanto, 2020) and phenolic compounds (Arriola, De Medeiros, Prudencio, Olivera Müller, & De Mello Castanho Amboni, 2016).

The consumption of edible bubbles, made of tapioca starch pearls or fruity calcium alginate bubbles, started in Taiwan in the 1980s. These bubbles are usually consumed with tea-based beverages, with or without added milk and fruit juices, creating a refreshing beverage known worldwide as bubble tea (Lin et al., 2019).

The calcium alginate edible bubbles have a rigid surface formed by calcium alginate and a flavored liquid inside. When popped, the edible bubbles provide a sensation of freshness that can be refreshing and pleasurable for the consumer (Nicholas, Chua, Teresa, Hazijah, & Zakaria, 2022). In addition, using these bubbles as a spherification agent may present a viable alternative for preserving bioactive compounds during gastrointestinal digestion.

Most studies apply a similar method, such as extrusion, to encapsulate different raw materials (Liu, Cheng, & Wu, 2020; Nicholas et al., 2022). This technique is efficient for the manufacture of alginate spheres; however, the interior of the formed bubbles tends to harden. Therefore, the innovation of this research consists of applying the reverse spherification technique imported from molecular gastronomy (Gomes, Simões, & Silva, 2020) to improve a food known as edible bubbles. This technique allows the coating of liquid material through the formation of a thin polymeric layer, giving rise to solid surface bubbles containing liquid inside (Tsai et al., 2017). In this context, the objective of this research was to assess the bioaccessibility of phenolic extracts from edible flowers and red fruits spherified within edible calcium alginate bubbles.