Optimization and characterization of pulsed electric field parameters for extraction of quercetin and ellagic acid in emblica officinalis juice

The effect of reversible permeabilization and post-electroporation resting on the survival of Thai basil (O. Basilicum cv. thyrsiflora) leaves during drying

Horticultural crops have a low tolerance to dehydration. In this paper, we show that the reversible electroporation (200 monopolar, rectangular pulses of 50 µs pulse duration, 760 µs between pulses and nominal field strength of 650 V/cm) of Thai basil leaves followed by 24 h resting before hot air drying at 40 °C enhanced the survivability of the tissues at certain levels of dehydration (moisture ratio = 0.2 and 0.1). However, this increased survival was rather limited. Through measurements of metabolic heat production during resting, rehydration kinetics, respiration and photosynthesis of the rehydrated leaves, we show that resting after the application of a reversible pulse-electric field (PEF) may allow a phase of hardening that has a protective effect on the cells, thus decreasing damage during the subsequent drying phase. Increased preservation of cell vitality would be associated with a more turgid and fresh-like rehydrated product, as cells would have the capacity to retain the rehydration water.

Green Extraction Methods for Extraction of Polyphenolic Compounds from Blueberry Pomace

In this study, green extraction methods—high voltage electrical discharges (HVED), pulsed electric field (PEF), and ultrasound-assisted extraction (UAE)—were compared in terms of extraction yield of total and individual polyphenolic compounds, as well as the antioxidant capacity of blueberry pomace extracts. All extractions were performed with methanol- and ethanol-based solvents. The highest total polyphenols content (TPC) (10.52 mg of gallic acid equivalent (GAE) per g of dry weight (dw)) and antioxidant activity (AA) (0.83 mmol TE/g dw) were obtained by PEF-assisted extraction in the ethanol-based solvent after 100 pulses and 20 kV/cm, which corresponds to an energy input of 41.03 kJ/kg. A total of eighteen individual polyphenols were identified in all investigated blueberry pomace extracts by high-performance liquid chromatography with the diode-array detector (HPLC-DAD) and liquid chromatography electrospray ionization tandem mass spectrometric (LC-(HESI)-MS/MS). The highest anthocyanin (1757.32 µg/g of dw) and flavanol (297.86 µg/g of dw) yields were obtained in the methanol-based solvent, while the highest phenolic acid (625.47 µg/g of dw) and flavonol (157.54 µg/g of dw) yields were obtained in the ethanol-based solvent by PEF-assisted extraction at the energy input of 41.03 kJ/kg. These results indicated that PEF is a promising green extraction method which can improve the blueberry pomace’s polyphenol extraction yield.

Comparative study of various processes used for removal of bitterness from kinnow pomace and kinnow pulp residue

The current study was focused on new approaches for debittering of by-products like kinnow pomace and kinnow pulp residue by using various food grade mild chemical methods, such as alkali treatment, acid treatment, and solventogenesis. Whereas in the studied various chemical treatments, the solventogenesis method with acetone resulted in maximum extraction of naringin and limonene from kinnow pomace and pulp residue and showed high acceptability for food product development. The acetone treatment was further optimized by RSM for the maximum extraction of naringin and limonene. Under optimized conditions, the maximum amount of naringin and limonene extracted were found to be 8.955, 2.122 mg/g from kinnow pomace and 9.971, 3.838 mg/g from pulp residue, respectively. This process can not only result in the effective utilization of agro-industrial by-product but also provide a sustainable solution to the environmental pollution caused by kinnow juice industry.

Extraction of bioactive compounds and essential oils from mediterranean herbs by conventional and green innovative techniques: A review

Market interest in aromatic plants from the Mediterranean is continuously growing mainly due to their medicinal and bioactive compounds (BACs) with other valuable constituents from essential oils (EOs). From ancient times, these plants have been important condiments for traditional Mediterranean cuisine and remedies in folk medicine. Nowadays, they are considered as important factors for food quality and safety, due to prevention of various deteriorative factors like oxidations and microbial spoilage. EOs have different therapeutic benefits (e.g. antioxidant, anti-inflammatory, antimicrobial, and antifungal), while BACs mostly affect nutritive, chemical, microbiological, and sensory quality of foods. Currently, many plant extracts are used for functional (healthy) foods, which additionally fuels consumer and industrial interest in sustainable and non-toxic routes for their production. EO yields from dried plants are below 5%. Their extraction is strongly dependent on the hydrophobic or lipophilic character of target molecules, hence the common use of organic solvents. Similarly, BACs encompass a wide range of substances with varying structures as reflected by their different physical/chemical qualities. Thus, there is a need to identify optimal non-toxic extraction method(s) for isolation/separation of EO/BCs from plants. Various innovative non-thermal extractions (e.g. ultrasound-, high-pressure-, pulsed electric fields assisted extraction, etc.) have been proposed to overcome the above mentioned limitations. These techniques are "green" in concept, as they are shorter, avoid toxic chemicals, and are able to improve extract yields and quality with reduced consumption of energy and solvents. This research provides an overview of such extractions of both BAC and EOs from Mediterranean herbs, sustained by innovative and non-conventional energy sources.

Natural Antioxidants in Foods and Medicinal Plants: Extraction, Assessment and Resources

Natural antioxidants are widely distributed in food and medicinal plants. These natural antioxidants, especially polyphenols and carotenoids, exhibit a wide range of biological effects, including anti-inflammatory, anti-aging, anti-atherosclerosis and anticancer. The effective extraction and proper assessment of antioxidants from food and medicinal plants are crucial to explore the potential antioxidant sources and promote the application in functional foods, pharmaceuticals and food additives. The present paper provides comprehensive information on the green extraction technologies of natural antioxidants, assessment of antioxidant activity at chemical and cellular based levels and their main resources from food and medicinal plants.