Recent microencapsulation trends for enhancing the stability and functionality of anthocyanins: a review

Abstract

Anthocyanins (ACNs) are water-soluble pigments in various fruits and vegetables known for their high antioxidant activity. They are used as natural food colorants and preservatives and have several medicinal benefits. However, their application in functional foods and nutraceuticals is often compromised by their low stability to heat, oxygen, enzymes, light, pH changes, and solubility issues. Spray drying has emerged as an effective microencapsulation technique to enhance the shelf life, quality, and stability of ACNs. This manuscript reviews the latest scientific developments in spray drying microencapsulation of ACNs-rich fruit extracts. Process optimization and the stability and physicochemical properties of the spray-dried, microencapsulated ACNs-rich powders are discussed. This review also covers functional food and nutraceutical applications and introduces novel encapsulation methods, such as freeze-drying, supercritical carbon dioxide (SC-CO₂), coacervation, drum drying, and electrospraying, highlighting their potential in improving the utility of ACNs-rich fruit extracts.

Keywords: Anthocyanins stability; Encapsulating agents; Functional food value; Optimized spray drying; Powder product.

Fig. 1

ACNs move from the synthesis site, the endoplasmic reticulum (ER), to the vacuole for storage. ER-derived vesicles facilitate anthocyanin transport to the vacuole, where they bind to the membrane via soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNARE) and release ACNs during the micro (1) and macro (2) autophagy processes. Several membrane proteins (multidrug and toxic compound extrusion (MATE), ATP-binding cassette (ABC), and bilitranslocase (BTL-like transporters) aid in the transport of ACNs into vacuoles and their sequestration in vacuolar inclusions (AVIs) in the membrane transporter-mediated pathway (3), Glutathione S-transferases (GSTs) mediate the conjugation of ACNs to generate the glutathione-ACNs conjugate, which serves as an intact and efficient means of transport from the ER to the vacuole. Adapted from Nistor et al. (2022) with modification

Fig. 2

Microencapsulation of ACNs extracts from various food sources and general chemical structure of ACNs and their anthocyanidins. R3 = sugar (glucose, arabinose, galactose, etc.). Adapted from Kozłowska and Dzierżanowski (2021) with modification

Fig. 3

Effect of encapsulating agent on the microstructure of microencapsulated ACNs powder with (a) GA (12%, w/v), (b) waxy starch (12%, w/v), and (c) MD (12%, w/v) without cellulose from Yousefi et al. (2010)

Fig. 4

Oral intake and mechanisms of microencapsulated ACNs in the human digestive system

Fig. 5

Schematic diagram of (a) a typical freeze-drying mechanism, (b) supercritical conditions, (c) ACNs coacervation, (d) double drum drying mechanism, (e) a typical electrospraying mechanism. Adapted from Bigazzi et al. (2020) with modifications

Fig. 6

Percentage encapsulation efficiency (EE) of various encapsulated ACN powders by referring to the optimal operation of different encapsulation techniques as reported by different authors. The straight line indicates 90% of EE. Different bar colors indicate the different techniques. Yellow, spray drying; blue, freeze-drying; purple, SC-CO₂; orange, coacervation; green, drum drying; dark red, electrospraying; numbers 1–17 referred to different authors. 1 – Fredes et al. (2018), 2 – Yingngam et al. (2018), 3 – Ribeiro et al. (2019), 4 – Xue et al. (2019), 5 – Pan et al. (2022), 6 – Laureanti et al. (2023), 7 – Zahed et al. (2023), 8 – Jang and Koh (2023), 9 – Nguyen et al. (2022), 10 – Xue et al. (2019), 11 – Santos et al. (2013), 12 – Gharanjig et al. (2020) 13 – Sarkar et al. (2020), 14 – Sakulnarmrat and Konczak (2022), 15 – Sakulnarmrat et al. (2021b), 16 – Atay et al. (2018), 17 – González-Cruz et al. (2020)