Microwave‐assisted forced convection drying effect on bioactive compounds of the Canadian blueberry leaves ( Vaccinium corymbosum )

Blueberry leaves as a promising sustainable source of polyphenols: Chemical composition, functional activities and future application perspectives

Blueberry leaves are a byproduct of blueberry cultivation, often overlooked despite their potential value. As global consumption of blueberries continues to rise, the area under cultivation expands, leading to an increased production of blueberry leaves. Blueberry leaves are a rich source of polyphenols, and in recent years, extensive research has been conducted on the composition and biological functions of these compounds. However, studies on blueberry leaves are often fragmented and lack a comprehensive overview of their potential applications. This review outlines the biosynthetic pathways of polyphenols in plants and compares the variations in polyphenol content and composition in blueberry leaves, influenced by factors such as cultivars, harvesting seasons, and extraction methods. Current research indicates that the primary constituents of blueberry leaf polyphenols (BLPs) are caffeoyl quinic acids, flavonols, and flavan-3-ols. These active compounds endow blueberry leaves with a range of functional properties, including antioxidant, anti-inflammatory, antibacterial, antiviral, antitumor, and metabolic syndrome-modulating effects. As a cost-effective and potentially beneficial by-product of agricultural production, blueberry leaves represent a promising area for further development. Therefore, this review discusses the opportunities and challenges associated with the applications of blueberry leaves, offering insights into their future processing, utilization, and potential for sustainable development.

Effect of intermittent microwave convective drying on physicochemical properties of dragon fruit

The study was carried out to investigate the effect of Intermittent microwave convective drying (IMCD) on the overall quality of dried dragon fruit in terms of total phenolic content, color change, and rehydration ratio. Three levels of microwave power (200-600 W) and a temperature of 60 °C for hot air were applied alternately throughout the process with three levels of pulse ratio such as 1:10, 1:20, and 1:40, respectively. The total phenolic content of the dragon fruit slice obtained by IMCD was ranged between 5.750 and 6.575 mg GAE/g dry weight. Within the experimental range of process variables under IMCD conditions, the drying efficiency, color change, and rehydration ratio of the dried dragon fruit slices were 15.287-51.930%, 18.643-24.847, and 1.908-3.239, respectively. The Weibull model scale (α) parameter was found to vary between 27.512 - 498.174 , while the shape (β) parameter was found to vary between 0.769 - 0.851 . The Weibull model parameters were shown to decrease with increasing microwave power at constant pulse ratio. The IMCD method produced a dried dragon fruit slices with reduced color changes and higher total phenolic content and rehydration ratio values. This investigation would contribute to the development of effective drying techniques for increased food quality and product consistency in the drying of diverse fruits and vegetables.