Blueberry anthocyanins: An updated review on approaches to enhancing their bioavailability

Blueberries are rich in anthocyanins, which have been studied for many years. Interest in these compounds has grown attributing to their possible therapeutic and beneficial effects, among which are the reduction of coronary heart disease, anticancer/antitumor, anti-inflammatory, and antidiabetic effects, as well as the improvement of visual acuity and cognitive behavior. However, the chemical instability of anthocyanins is one of the major limitations on their application. Anthocyanins are susceptible to degrade, leading to the loss of color. Several environmental factors could significantly influence the stability of anthocyanins, including temperature, light, oxygen, enzymes, and pH. The instability of anthocyanins would likely result in their poor bioavailability. This review provides critical information for a better understanding of the bioavailability of blueberry anthocyanins. Furthermore, recent findings regarding different approaches to increase the bioavailability of blueberry anthocyanins will be discussed. More than half of the nearly 100 papers cited in this review were published in the last decade. The improvement in anthocyanin stability is an important problem that needs to be solved urgently. A major challenge in food applications is to find a strategy to overcome this obstacle of anthocyanin's instability, which could lead to low bioavailability. Therefore, the utilization of different formulations such as nanoparticulate systems, microencapsulation, and protein complexes could potentially improve the bioavailability after ingestion and during digestion. Developing effective novel systems to increase stability of anthocyanins and thus its bioavailability in the human body following ingestion, can enhance its nutraceutical use in the context of prevention and/or cure of diseases.