Hot Pressurized Liquid Extraction of Polyphenols from the Skin and Seeds of Vitis vinifera L. cv. Negra Criolla Pomace a Peruvian Native Pisco Industry Waste

Erik E Allcca-Alca,Maximiliano Martínez-Cifuentes,Nilton C León-Calvo,José Ricardo Pérez-Correa,Nils Leander Huamán-Castilla,Olivia M Luque-Vilca,María Salomé Mariotti-Celis

doi:10.3390/agronomy11050866

Abstract

The pisco industry in Peru generates large amounts of grape pomace, which is a natural source of bioactive compounds with potential nutraceutical applications. Hot pressurized liquid extraction (HPLE) with water-ethanol solvent mixtures (20–60%) at high temperatures (100–160 °C) was applied to recover polyphenols from the skin and seeds of a Peruvian pisco-industry grape-pomace waste. At the same HPLE conditions (60% ethanol, 160 °C), the seed fraction extracts contained ~6 times more total polyphenol and presented ~5 times more antioxidant activity than the extract from the skin fraction. The lowest ethanol concentration (20%) and the highest temperature (160 °C) achieved the highest recovery of flavanols with 163.61 µg/g dw from seeds and 10.37 µg/g dw from skins. The recovery of phenolic acids was maximized at the highest ethanol concentration and temperature with 45.34 µg/g dw from seeds and 6.93 µg/g dw from skins. Flavonols were only recovered from the skin, maximized (17.53 µg/g dw) at 20% of ethanol and the highest temperature. The recovery of specific polyphenols is maximized at specific extraction conditions. These conditions are the same for seed and skin extractions. This alternative method can be used in other agroindustrial wastes in order to recover bioactive compounds with potential applications in the pharmaceutical and food industry.

Highlights

Peru produces ~9.5 million L of pisco from Vitis vinifera L. cv
In this research, we evaluated the effect of water-ethanol mixtures (20–60%) at high temperatures (100–160 ◦C) on the recovery of the total polyphenol content, antioxidant capacity, and specific families of polyphenols of extracts obtained separately from the skins and seeds of Negra Criolla pomace, which is an agro-industrial residue from the Peruvian pisco industry
The total polyphenols content (TPC) of the extracts obtained from the skins (0.46–1.98 mg Gallic acid equivalent (GAE)/g dw) and seeds (5.66–12.54 mg GAE/g dw) fractions presented significant differences (p < 0.05) (Table 1)

Summary

Introduction

Negra Criolla grape [1], whose production generates significant quantities of grape pomace (skin and seeds), which is an agroindustrial waste without any commercial value causing an environmental management problem [2] Both skin and seed fractions of this residue present high concentrations of different specific families of phenolic acids, flavanols, flavonols, and stilbenes [3]. The molecular weight of polyphenols can vary between 200 Da and 3500 kDa, the presence of hydroxyl groups in their chemical structure confers bioactive properties related to the prevention of degenerative diseases [4,5,6] These bioactive compounds are used to produce functional ingredients for the food, nutraceutical, and pharmaceutical industries [7]. Developing sustainable technologies for the optimal extraction of these compounds is still attractive and challenging

Methods

Results

Conclusion