Commercial Production of Anthocyanins from Subtropical Fruits

Abstract

Fruit crops grown in climatic conditions between temperate and tropical are known as subtropical fruit crops. The most common subtropical fruits are citrus fruits such as oranges, grapefruits, lemons, and limes. Other subtropical fruits include dates, figs, olives, grapes, kiwi or Chinese gooseberry, persimmon, stone fruits (apricot, plum), pomegranates, certain types of avocados, guava, litchi, cherry, finger lime, mock strawberry, pear, naartijie, and tamarillo. Anthocyanins (in Greek anthos means flower and kianos means blue), the phenolic compound referred to as flavonoids, are widely present throughout the plant system. Anthocyanins are generally isolated from a variety of plants, including carrots, cabbage, corn, hibiscus, and sweet potato. However, berries have been documented as the chief source of anthocyanin, accounting for 29.17% of all sources, followed by black rice (8.33%), black carrot (8.33%), sour cherry (8.33%), and grape (8.33%). Other anthocyanin sources include purple maize, pomegranate fruit, saffron, banana, and mao fruit. Depending on the predominance, berries are categorized as cyanidin-based or pelargonidin-based sources. Interestingly, most of the botanical sources of anthocyanins are cyanidin-based, with the exception of strawberries (rich in pelargonidin). Anthocyanins play a significant role in human nutrition and in the food industry as colorants. Anthocyanins are extremely sensitive compounds that may degrade during commercial processing. So, there is a need to protect anthocyanin from external factors. For this reason, researchers are paying more attention to the microencapsulation of anthocyanins. Generally, encapsulation techniques are categorized into five groups: spray drying, freeze drying, ion gelation method, emulsion method, and coacervation. Spray drying was found to be the most investigated method for encapsulating anthocyanins. Maltodextrin, an economic and efficient drying agent, was the most commonly reported biopolymer in this method. Freeze-dried microcapsules, for example, have been demonstrated to have greater anthocyanin stability and antioxidant activity than spray-dried microcapsules. Other techniques, including emulsion and ionic gelation, can also be utilized to encapsulate anthocyanins.