Characterization of microencapsulated spinach extract obtained by spray-drying and freeze-drying techniques and its use as a source of chlorophyll in a chewing gum based on Pistacia atlantica

The Baneh tree, or Pistacia atlantica subspecies kurdica, is a medicinal and food plant native to Iran. It grows wildly and is well-known for its therapeutic properties, which are derived from the bioactive compounds in its different parts (Rahman, 2018). One of the products of this tree is a gum that exhibits antioxidant, antibacterial, anti-inflammatory, and anticancer properties (Khamevar et al., 2021; Rahman, 2018). Chewing gum (CG) is a product that is familiar to almost everyone and is often bought impulsively (Caracciolo et al., 2019). Therefore, developing a CG from the Baneh tree could be beneficial. It could not only improve societal health but also reduce the negative impact of discarded synthetic gum on wildlife.

Color is a key factor in customer preferences for food products, and creating a CG necessitates the use of a natural colorant. Chlorophyll (CHL) and its natural and semi-synthetic derivatives have seen growing demand as food colorants and supplements due to their health benefits (López-Cruz, Sandoval-Contreras, & Iñiguez-Moreno, 2023). CHL has antioxidant, anti-mutagenic, and xenobiotic enzyme modulating properties, and can induce apoptosis in cancer cells (Hayes & Ferruzzi, 2020). However, its use is limited because it is unstable under environmental stressors and adverse conditions such as enzymatic reactions or acidic mediums. It also has poor water solubility (Agarry et al., 2022; Hsiao et al., 2020). Therefore, these issues need to be addressed before CHL can be used in food products.

Encapsulation is a technique that creates physical barriers around bioactive compounds to form “micro/nanocapsules”. This process can extend the shelf life of encapsulated herbal products and improve their processability, stability, delivery, cost, etc. (Deladino, Anbinder, Navarro, & Martino, 2008; Rajabi, Ghorbani, Jafari, Mahoonak, & Rajabzadeh, 2015). Spray drying (SD) and freeze drying (FD) are two encapsulation methods that use wall material to protect bioactive compounds. Gum Arabic (GA) and maltodextrin (MD) are common carriers used for encapsulation. MD has excellent water solubility and low viscosity at high concentrations but lacks emulsifying activity (Kenyon & Anderson, 1988; Schlindweinn et al., 2022). GA has good solubility and emulsification capabilities but is expensive, limited in availability, and can cause viscosity issues at high concentrations (Al-Hamayda, Abu-Jdayil, Ayash, & Tannous, 2023). Combining these two substances can balance these properties and mitigate their respective disadvantages. Studies have shown that the encapsulation efficiency of bioactive compounds was significantly higher when MD was used with GA compared to MD alone (Rajabi et al., 2015; Ravichandran et al., 2014; Sukri, Multisona, ZaidaSaputra, Mahani, & Nurhadi, 2020). Furthermore, the morphological characteristics of SD and FD powders are significantly different. The morphology of encapsulated powders can be evaluated from three distinct perspectives: the influence of TS of feed, the ratio between MD and GA, and the encapsulation methodology. These factors cause changes in the morphology of encapsulated powders in terms of size, shape, and porosity (Fu, You, Quek, Wu, & Chen, 2020; Rajabi et al., 2015; Zahran, Bat, & Şahin-Yeşilçubuk, 2022).

Some research have been carried out on the production of synthetic CG using encapsulated CHL from alga sources. For instance, Palabiyik et al. (2018) and Toker (2018) utilized spray-dried microalga biomass as a natural coloring agent in synthetic gum based CG. To our knowledge, no research has been conducted on the production of a natural-based CG containing microencapsulated CHL (mCHL) from spinach as a functional food. In recent years, the demand for functional foods with added health benefits has grown significantly. However, one area that remains largely unexplored is the production of natural-based CG using Pistacia atlantica gum as a base and spinach as a source of CHL. This research is significant as it is the first to explore this area, potentially paving the way for a new type of functional food. The development of such a product could provide consumers with an easy and enjoyable way to receive the health benefits of CHL derived from spinach. Furthermore, this research could have broader implications for the food industry by demonstrating a novel delivery system for nutrients using Pistacia atlantica gum. This could lead to the development of a range of new products, ultimately contributing to better health outcomes. The aims of this study were categorized into two stages: Initially, the CHL was extracted from spinach leaves, and we discussed the impact of the encapsulation method, the proportions, and concentrations of GA and MD on the physicochemical properties of mCHL in terms of a_w, moisture content, powder yield, encapsulation efficiency, morphology, crystalline structure, and storage stability. Subsequently, we elaborated on the process of preparing a chewing gum using Pistacia atlantica gum. This gum was fortified with SD- and FD-mCHL, and the properties of the produced chewing gums were assessed in terms of CHL release profile, textural properties, and sensorial attributes.