Valorization of Banana and Red Beetroot Peels: Determination of Basic Macrocomponent Composition, Application of Novel Extraction Methodology and Assessment of Biological Activity In Vitro

Danijela Šeremet,Ksenija Durgo,Stela Jokić,Ana Mandura,Ana Huđek,Jasna Jurasović,Aleksandra Vojvodić Cebin,Draženka Komes

doi:10.3390/su12114539

Danijela Šeremet, Ksenija Durgo + Show 6 more

Open Access

https://doi.org/10.3390/su12114539

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Abstract

The nutritional and bioactive content of banana and red beetroot peels was investigated. The basic macrocomponent composition was determined using standard AOAC (Association of Official Analytical Chemists) methods, while the recovery efficiency of bioactive compounds was investigated using conventional and innovative extraction techniques (subcritical water extraction, ultrasound- and microwave-assisted extraction). Extracts were analyzed for biological effects in vitro on human hepatic, tongue and colon cancer cell lines. A macrocomponent analysis revealed a notable amount of dietary fiber in banana and beetroot peels (39.0 and 33.6% dmb) and a relatively high content of protein in beetroot peel (18.3% dmb). Regarding the micronutrients-minerals, banana and beetroot peels were shown to be a very good source of potassium (75.06 and 41.86 mg g−1 dmb). Both extracts of banana and beetroot peels obtained by conventional extraction - decoction (100 °C, 20 min) exhibited the highest total phenolic content and antioxidant capacity. Additionally, in banana peel, these extracts were the richest in dopamine content (12.63 mg g−1 dmb). Extraction by infusion (80 °C, 30 min) yielded a beetroot peel extract with the highest total betacyanin content (9.80 mg g−1 dmb). Biological effects in vitro were dose- and time-dependent, as well as influenced by the presence of polysaccharides.

Highlights

For the period between 2009 and 2050, the world population is predicted to grow by a third, which will result in a substantial increase in food demand [1]
Banana peel represents a great source of phenolic compounds, like gallocatechin, and catecholamines, especially dopamine, whose content was found to be much higher in the peel compared to the banana pulp [9,10]
The dried banana and red beetroot peels were milled into powder and sieved through a screen with pores of 450 μm, to obtain fractions to be used in the analyses

Summary

Introduction

For the period between 2009 and 2050, the world population is predicted to grow by a third, which will result in a substantial increase in food demand [1]. The agro-industrial sectors, besides providing food to the whole population, are searching for the new eco-friendly and sustainable forms of food production, including agro-industrial waste reutilization. Agro-industrial waste includes stalks, stems, leaves, roots, molasses, husks, peels, etc., that are known to contain high-value ingredients, such as nutrients and bioactive compounds [2], pointing to wider possibilities of application in the food industry. Banana (Musaceae) is a tropical fruit available throughout the whole year and, after tomato, the most consumed fruit in the world [3], with an annual production of 115 million tons in 2018 [4]. Since approximately 30% of banana fruit is comprised of inedible peel [5], it is obvious that, on a global scale, a lot of peel waste is generated annually in fruit industries, as well as in households. Banana peel represents a great source of phenolic compounds, like gallocatechin, and catecholamines, especially dopamine, whose content was found to be much higher in the peel compared to the banana pulp [9,10]

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