Nuts and their co-products: The impact of processing (roasting) on phenolics, bioavailability, and health benefits – A comprehensive review

Abstract

Nuts serve as important healthful snacks worldwide. They are highly desirable due to the presence of numerous essential macro- and micronutrients and health-promoting phenolic compounds (polyphenols). Nuts are usually consumed either as raw (natural) or as roasted. In addition, nuts and their co-products have been demonstrated to be rich sources of phenolic compounds that possess various health-beneficial properties. Therefore, inclusion of these phenolic compounds from nut co-products into the human diet is highly recommended as these may provide inexpensive sources of natural antioxidants for use as functional food ingredients and nutraceuticals. Hence, the phenolic compositions and antioxidant activities of nuts (natural and roasted) and their co-products (such as skin, hard shell, hull, and pellet) are discussed in detail. The impact of processing (roasting) on nut phenolics and antioxidant activities are highlighted. The bioavailability and health benefits of the phenolic compounds from nuts, especially their co-products are also discussed. Research findings from the existing literature published within the last 10 years have been compiled and summarised.

Keywords

• Nut co-products
• Roasting
• Phenolic compounds
• Antioxidant activity
• Bioavailability
• Health benefits