Effect of microwave and infrared drying over polyphenol content in Vaccinium meridionale (Swartz) dry leaves

Abstract

In the present work the drying of blueberry (mortiño) leaves (Vaccinium meridionale‐Swartz) was done using a hybrid equipment with infrared drying and normal microwave drying. During the drying tests there was a record of moisture content versus time; samples of leaves were taken during the drying time to analyze total phenol (PT) content, FRAP assay and catechin measures by HPLC‐DAD. The PT analysis shows that its content in dry blueberries, increased 12 times more with the microwave drying than infrarred drying. While FRAP assay shows that dry blueberries antioxidant capacity increased nine times more with microwave process in comparison to infrared process. In the catechins content by HPLC‐DAD in dry blueberries, a better result for concentration was found in microwave process than in infrared process. Similar result occurred for (−) epicatechin. Finally, (+) catechin concentrations in blueberry leaves were compared with commercial materials such as tea leaves and mate leaves. Practical applications The consumption of nutraceutical products rich in polyphenols has become important in the last decades. In this research, the effect of microwave and infrared drying on the content of polyphenols on blueberry leaves (Vaccinium meridionale, Swartz) was studied because it was found in previous studies that the leaves contain a potential of polyphenols that can be used to develop nutraceutical beverages similar to tea drinks.

Microwave assisted drying and extraction technique; kinetic modelling, energy consumption and influence on antioxidant compounds of fenugreek leaves

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Drying characteristics and modeling of apple slices during microwave intermittent drying

“…Drying is the most common processing technique for materials preservation by preventing the microbiological spoilage (Borda‐Yepes et al, ). Microwave drying is applied as an efficient method for agricultural products dehydration.…”

Infrared Drying Trends Applied to Fruit

“…This is why if the research was based on the search for infrared drying information, the most keywords found were related to these topics. Some of the authors who mention the most repeated keywords in the articles are Rashid et al (2019), Daniel and Onwude (2019), Khampakool et al (2019), and Borda-Yepes et al (2019, among others.…”

“…Rezaei et al (2019) used linear and algorithmic models to determine the shrinkage or reduction of the area of potato slices, managing to optimize the adjustment of the power of the microwave with which the infrared used for drying is applied. Borda-Yepes et al (2019) used the drying curves to determine the moisture present in a product, which was dried by infrared and by microwaves, concluding that microwave drying preserves better qualities than infrared does. Wang (2019) compared HAD, infrared drying, and microwave drying and determined which of these was more appropriate and presented better conditions for processing shiitake mushrooms, determining that microwave drying considerably reduced drying time and higher polysaccharide content compared to the other methods.…”