Pretreatment of tamarind pericarp to increase antioxidant availability and its application in a functional food

Diverse researchers have considered by-products of food and agricultural processing industries as a source of antioxidants. Tamarind (Tamarindus indica) is a leguminous tree, native from tropical Africa bearing edible fruit. The fruit is composed of 30% pulp, 40% seed, and 30% pericarp. Currently, tamarind pericarp is a waste from tamarind processing (approximately 54,400 tons of pericarp in 2012 worldwide) and is contributing to environmental contamination. This research aimed to determine the effect of maceration, microwaves, and ultrasound on the increase in the antioxidant availability in tamarind pericarp and its incorporation as a functional ingredient in cookies (5 and 10% substitution). Antioxidant content, antioxidant activity, proximate, and sensorial analysis of the cookies were conducted. The microwave method was the best pretreatment compared with sonication and maceration since it showed 1.3-fold higher amounts of phenolic compounds and 1.2-fold higher antioxidant capacity. The 10% substitution of tamarind pericarp powder in cookies, significantly increased the fiber content (four-fold) and phenolic compounds content (2.6-fold) and the product presented good acceptance in a sensorial test. Thus, tamarind pericarp powder could be considered as an antioxidant and fiber source and could be used as a functional ingredient in food products.