Biowaste as a Potential Source of Bioactive Compounds-A Case Study of Raspberry Fruit Pomace.

Slađana Krivokapić,Milorad Vlaović,Biljana Damjanović Vratnica,Andrej Perović,Svetlana Perović

doi:10.3390/foods10040706

Abstract

Raspberry fruit pomace, a byproduct of juice production, was studied as a potential source of antioxidant compounds. Target high-performance liquid chromatography analysis of important polyphenolic compounds (gallic, p-coumaric, caffeic, quercitrin, chlorogenic, and ellagic acid) was performed together with analysis of total phenolic content (TPC), total flavonoid content (TFC), total anthocyanins content (TAC), and antioxidant capacity (via ferric reducing antioxidant power (FRAP) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) assays). The differences in polyphenolic content of Rubus idaeus L. pomace were evaluated following ultrasound-assisted extraction and conventional maceration with different organic solvents. Additionally, the yield of free phenolics was measured in hydrolyzed pomace extracts. The results obtained show that the ultrasound method maximizes the quantity of antioxidant compounds in terms of TPC (27.79 mg/L gallic acid equivalent (GAE)), TFC (8.02 mg/g quercetin equivalent (QE)), TAC (7.13 mg/L cyanidine-3-glucoside equivalent (C3G Eq)), caffeic (19.17 µg/g), chlorogenic (3.56 µg/g), ellagic (105.52 µg/g), and gallic acids (8.75 µg/g), as well as FRAP (1002.72 µmol/L) and DPPH assays (969.71 µmol/mL vitamin C equivalent (vit C Eq); 567.00 µmol/100 g Trolox equivalent (TE)). On the other hand, conventional maceration maximizes the yield of quercetin and p-coumaric acid. In terms of biowaste valorization, raspberry fruit pomace has a promising industrial potential and may prove to be useful in the development of antioxidant dietary supplements.

Highlights

The impairment of metabolic and other life-sustaining molecular processes leads to significant oxidative stress and the production of reactive oxygen species
Prolonged oxidative stress in humans may result in the onset and exacerbation of any of the plethora of conditions associated with oxidative stress, such as premature aging, cardiovascular diseases, chronic obstructive pulmonary disease, neurodegenerative diseases such as Alzheimer’s or Parkinson’s disease, various forms of cancer, and sarcopenia
Adequate fruit and vegetable intake is epidemiologically justified as a strategy to counter the effects of oxidative stress and inflammation that are associated with heart diseases and diabetes—both of which have a high mortality rate worldwide

Summary

Introduction

The impairment of metabolic and other life-sustaining molecular processes leads to significant oxidative stress and the production of reactive oxygen species. Adequate fruit and vegetable intake (more than 10 servings per day) is epidemiologically justified as a strategy to counter the effects of oxidative stress and inflammation that are associated with heart diseases and diabetes—both of which have a high mortality rate worldwide. Up to 5.5 MMT of waste is created during juice production [10] Secondary metabolites, such as fibers, carotenoids, anthocyanins, and phenols, are wasted, along with the fruit pomace, during production [11]. Among others, these compounds have antioxidant, antimicrobial, and UV-protective properties, and might serve as natural preservatives, additives, emulsifiers, thickeners and bulking agents, dyes/colorants, etc. These compounds have antioxidant, antimicrobial, and UV-protective properties, and might serve as natural preservatives, additives, emulsifiers, thickeners and bulking agents, dyes/colorants, etc. Readily found in fruit biowaste, offer low-cost, integrated, and environmentally friendly alternatives to their chemically synthesized counterparts, and are an environmentally conscious choice with promise as a tool in the achievement of a sustainable circular economy [10,11,12,13,14]

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