Emerging Technologies

Polyphenols from Vegetables and Fruits By-Products: The Recovery, Valorization and Re-Utilization How to Develop an Integral & Perfect Strategy? III. Emerging technologies, safety & cost issues

Dr. Charis M. Galanakis R&I Director

ISANH Polyphenols Pre-Conference Workshop 4 June 2014

Conventional Recovery Technologies Restrictions

 Overheating of the by-products’ matrix  High energy consumption & general cost  Loss of functionality & poor stability of the final product

 Accomplishment of increasingly stringent legal requirements on materials safety

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Emerging Recovery Technologies Advantages

 Based on non-thermal concepts

 Promise to surpass most of conventional technologies restrictions & optimize processing efficiency

 Enhance stability of the final product  Moisture- & pH-triggered controlled release of bioactive compounds

 Enhance bioavailability

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Could be easily adapted in the recovery of polyphenols from fruit & vegetable byproducts 3

Recovery of polyphenols from fruit & vegetable byproducts I. Macroscopic Pre-treatment

Emerging Technologies

Foam-mat Drying, Electro-osmotic Dewatering Low-temperature Plasma Treatment

 Are suggested for their application in various processes within food industry

II. Macro- & Micro- molecules Separation Colloidal Gas Aphrons, Ultrasound-Assisted Crystallization, Pressurized MicrowaveAssisted Extraction

III. Extraction Ultrasonics, Laser Ablation, Pulsed Electric

!

Could be easily adapted in the recovery downstream of polyphenols from by-products

Field, High Voltage Electrical Discharge, Liquid Membranes, Pervaporation

IV. Isolation & Purification Magnetic Fishing, Aqueous TwoPhase Separation, Membrane Ion Exchange Chromatography

V. Product formation Galanakis, C. M. (2012). Recovery of high added-value components from food wastes: conventional, emerging technologies and commercialized applications. Trends in Food Science & Technology, 26(2), 68-87.

Nanotechnology, Pulsed Fluid Bed agglomeration 4

Recovery of polyphenols Ι. Macroscopic Pre-treatment

• Foam mat drying

Reduce water content

• Electro-osmotic dewatering

• Low-temperature plasma

Non-thermal microbial or enzymatic inactivation of the food matrix

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Foam Mat Drying Description

Advantages

 Old technique (in early 70s)

 High stability against deteriorative

 Attracted attention due to the efforts to diminish thermal processes

 Based on the conversion of a semisolid material to stable foam

microbial & biochemical reactions

 Lower temperatures

& shorter

drying time

 Removal of water from heatsensitive & viscous substrates

• using inert gases

• high sugar by-products

• adding foaming agents

• Mango Pulp

• supplying rapidly hot air

• Apple puree

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Electro-osmotic Dewatering Description

 Conventional pressure consolidation with electrostatic effects • Induced electrochemical double layers • Formed at the particle-water interface of colloidal aqueous suspensions

 No over dry surface  Effective for gelatinous particles based solid-liquid mixtures Does not operate properly for high viscosity liquids

Tuan P.-A. & Sillanpää (2010) Migration of ions and organic matter during electro-dewatering of anaerobic sludge, Journal of Hazardous Materials, 173(1-3), 54–61.

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Recovery of polyphenols ΙI. Separation of Macro- & Micro- molecules

• Colloidal gas aphrons

Phenols (gallic acid) & proteins (β-casein) recovery

• Ultrasound-assisted crystallization

Whey protein removal acceleration & lactose recovery

• Pressurized microwaveassisted extraction with mechanical pressure

Recovery of several metabolites of different structures & polarities,

• Terpenes • Flavonoids • Pectin 8

Colloidal Gas Aphrons Description

 Colloidal gas aphrons are surfactantstabilized micro-bubbles (10-100 μm)

 Generated by intense stirring of a surfactant solution at high speeds prior to encapsulation in a soapy film

http://www.seas.ucla.edu/~pil on/photos.htm

 Increased interfacial area & high stability compared to conventional foams

 Can be easily be pumped from the generation side to the point of use without loss of their original structure

Presence of surfactant in the product stream

Morphological illustration of CGA dispersion during drainage time : 10, 300 & 600 μm

Moshkelani & Amiri, (2008) Electrical conductivity as a novel technique for characterization of colloidal gas aphrons (CGA). Colloids and Surfaces A: Physicochemical and Engineering Aspects, 317, 262-269. 9

Pressurized microwave-assisted extraction Description

 Advantages of microwave preheating

pressure treatment

 Accelerated process & low solvent consumption  Pressure can be applied in series (i.e. as a pretreatment step) or simultaneously with microwave extraction

Possible degradation of thermolabile ingredients Target Compound/Food Waste Source

Applied technologies

Pectin/Orange albedo

Recovery yield

g/ 100 g waste dm

g/ 100 g compound contained in the waste

Microwave-assisted extraction

0.8

Liu et al. (2006)

Soxhlet extraction

1.7

Liu et al. (2006)

Microwave- & pressure-assisted extraction, filtration, centrifugation

19.6

Japón-Luján & Luque de Castro (2007)

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Recovery of polyphenols ΙII. Extraction

 A dynamically developing area in applied research & industry • Ultrasound waves

• Laser ablation

 Accelerated heat & mass transfer

• Pulsed electric field

 Selective separations in different

• High voltage electrical discharge

phases (solid, liquid, vapors)

• Liquid membranes • Pervaporation

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Ultrasound Waves Characteristics

 Accelerate heat & mass transfer by disrupting the plant cell walls

 Facilitates the release of extractable compounds, i.e. phenols from citrus peel

 Extraction can be completed in min • High reproducibility • Low solvent consumption An additional filtration step is required

Schematic of ultrasound-assisted Soxhlet extraction

Koning, S. Janssen, H.-G., & Brinkman, U. A. T. (2009). Modern Methods of Sample Preparation for GC Analysis, Chromatographia Supplement,69, S33-S78

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Pulsed Electric Fields Description

 An external field can induce critical electrical potential across the cell membrane

• Pores development • Breakdown • Increased permeability • Accelerated mass transfer

Scheme of the co-linear PEF treatment chamber

Puértolas, E., López, N., Saldaña, G., Álvarez, I., & Raso, J. (2010) Evaluation of phenolic extraction during fermentation of red grapes treated by a continuous pulsed electric fields process at pilot-plant scale, Journal of Food Engineering, 98(1), 120-125.

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High-voltage electrical discharge Description

 Liquid samples are placed in a chamber between two electrodes  Short pulses (40-60 kV/cm, 2-5 μS) are applied to produce breakdown of liquid & fragmentation particles

 No need to add a solvent Requires high air generation capacity Target Compound/Food Waste Source


Phenols/ white grape pomace

Recovery yield g/ 100 g waste dm


Water extraction

0.26

Boussetta et al. (2009)

Water extraction & high voltage electrical discharge

0.44

Boussetta et al. (2009)

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Laser Ablation Description

 Extraction is conducted with a pulsed laser  Does not require solvents  Easily automated

 Minimal & gentler heating Target Compound/Food Waste Source


Pectin/orange peel

Panchev et al. (2011)

Recovery yield g/ 100 g waste dm


Drying, acid-assisted extraction

13


Laser ablation, drying, acid-assisted extraction

16.5


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Pervaporation Characteristics

 Separation of liquid mixtures by means of partial vaporization across a semi-selective membrane An effective pre-treatment step is required to avoid fouling

Advantages • Avoiding heat damage to sensitive aromas • Low energy consumption • Absence of solvents-elimination of separation steps

http://www.chemie.uni-duesseldorf.de 16

Liquid Membranes Characteristics

 The barrier is formed by a liquid film

 Elution of aromas & solutes  High selectivity & efficient energy use

• Separates 2 miscible liquids

• Controls mass transfer between both phases Low stability has limited the industrial exploitation

A solute from the liquid phase is transported across the membrane to stripping phase by diffusion

Ferraz, H.C., Duarte, L. T., Di Luccio M., Alves T. L. M., Habert, A. C., Borges, P. (2007). Recent achievements in facilitated trasport membranes for separation processes, Brazilian Journal of Chemical Engineering, 24(1). DOI: http://dx.doi.org/10.1590/S0104-6632200700010001

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Recovery of polyphenols ΙV. Isolation & Purification • The contact of two immiscible liquid phases has also been employed at this stage

 Aqueous two-phase separation

• Magnetic properties of ionexchange groups

 Magnetic fishing

• Combination of conventional techniques

 Ion exchange chromatography Membrane Processes

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Aqueous Two-Phase Separation Characteristics

 Very efficient for the extraction of proteins & enzymes

Incompatibility of two different hydrophilic polymers in the common aqueous solutions of polymers & salts above certain critical concentrations

• Whey β-lactoglobulin & α-lactalbumin partitioning • Citrus ascorbic acid isolation

 Mild condition & preservation of labile ingredients

 Less damage of the extracted molecules

Long separation time & numerous required processing steps

Persson, J., Johansson, H.-O., Tjerneld, F. (1999). Purification of protein and recycling of polymers in a new aqueous two-phase system using two thermoseparating polymers. Journal of Chromatography A, 864(1), 31-48.

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Recovery of polyphenols V. Product formation

 Modern encapsulation  Pulsed electric field

Nanotechnology Fluidized bed agglomeration • Particle fluidization by hot air flow • Particle wetting caused by the atomization of a solvent or liquid binder

Enhanced in pulsed fluid regime that reduces air & energy consumption 20

Nanoemulsions Characteristics

 Part of a broad class of multiphase colloidal dispersions

 Non-equilibrium systems of

 Fabrication proceeds: • High energy

• Low energy

nanometrix droplet size (10-100 nm) • High efficiency • Bioavailability • Physical stability

Capable of generating intense disruptive forces

Spontaneous formation of droplets within mixed oilwater-emulsifier systems

Popular in industrial applications & large scale productions 21

Nanoemulsions - Examples Emulsifiers

 Curcumin

Lecithin

(up to 200 nm)

 Grape marc extract

High pressure homogenization

Corn oil

(up to 200 nm) Amendola et al. (2011)

 β-carotene (280 nm)

Dissolving

Homogenization

Hexane

 β-lactoglobulin

Evaporation

(up to 100 nm) Silva et al. (2011); Troncoso et al. (2011) 22

Other Nano-formulations Nanocapsules

 Vesicular systems in which the active compound is confined to a cavity consisting of an inner liquid core surrounded by a polymeric membrane

 β-carotene (liposoluble)

Coating material Alginic acid-calcium cross-links

Naturally color waterbased foods (dark orange to yellow)

Nanocrystals

 More specific applications  During acid hydrolysis of crude crab shells that disperse chitin spontaneously into rod-like crystalline particles 23

Emerging Technologies Safety & Cost Issues

 Govern the final decision for the selected methodology

 i.e. emerging technologies could be too sophisticated in comparison to the yield improvement that they are promising

(a) investigate particular recovery stages Cost estimations are rather impossible

(b) include different technologies in each stage (c) deal with numerous substrates & waste streams of several contents

(d)Only laboratory scale experiments Safety consideration concern the unknown impact of innovative technologies & not the proven negative effects on consumers 24

Conventional Technologies


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I. Macroscopic Pre-treatment Conventional technologies • Concentration • Centrifugation

Safe Widely applied in different food industry sectors & products

• Microfiltration

 Thermal concentration deteriorates the initial matrix & accelerates Maillard by-product formation of unknown origin & impact on human health

 Vacuum processes (i.e. freeze drying) demand additional energy consumption resulting in higher operational cost

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I. Macroscopic Pre-treatment Emerging technologies

 High capital cost due to the large surface area • Foam-mat drying

 Reduction in energy consumption can reach 80% compared to traditional dryers

 Higher capital cost due to pressure or • Electro-osmotic dewatering

vacuum conditions

 Safety precautions must be taken during processing

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I. Macroscopic Pre-treatment Emerging technologies

 Effective, but expensive  Low operational cost with regard to consumption • 1 tn/d: 90 kW/h x 0.05$/kW/h = 4.5 $/h • Cold plasma

 High input cost due to the input feed gas • N2: 9-72 $/h • He: 636-9096 $/h

 Chemical residues & toxicological effects have not been studied yet

Challenge

 Reducing feed gas consumption & investigating toxicological effects in the by-product substrate 28



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II. Macro- & Micro-molecules Separation Conventional technologies • Ultrafiltration

Cheap & Safe

• Alcohol Precipitation

Emerging technologies • Colloidal gas aphrons

• Ultrasound-assisted crystallization • Pressurized microwaveassisted extraction

Cheap Safety depends on the use of biodegradable & non-toxic surfactants

Green & Safe High investment cost

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III. Extraction Conventional technologies • Acid • Alkali • Solvents • Supercritical fluids

• Microwaves • Hydrodistillation

• Steam diffusion

Safe If the involved materials exist inherently in foods or possess food grade nature

 Ethanol  Citric acid  CO2

Methanol Hydrochloric acid

 Moderate investment  Less concentrated acids  Relatively high energy consumption  Non-toxic, but increased temperatures cause deterioration 32

III. Extraction Emerging technologies

• Ultrasounds

• Pervaporation

• Liquid membranes

Safe Low investment cost & reduced energy consumption

Safety Depends on the organic phase & surfactant applied

 Relatively Cheap

Instability increases the cost

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III. Extraction Emerging technologies

• High voltage discharge

High capital cost & energy consumption

• Laser Ablation

Safety precautions during handling

Challenge

 Energy overconsumption & complicated problems should be solved

• Pulsed Electric fields

High capital cost i.e. fruit mash disintegration cost 150,000€ for a unit of 10 kJ/Kg , (~30 kW power) & a production of 10 tn/h Töpfl, 2006 34



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IV. Isolation & Purification Conventional technologies Safe • Nanofiltration (NF) • Electrodialysis (ED)

 Cheap, but ED possesses high cost than NF  Operational cost depends on the frequency of membrane sheet discharge

Safety • Adsorption • Chromatography

Depends on the toxicity of the materials involved in the process Regeneration & cleaning efficacy affects proportionally the cost

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IV. Isolation & Purification Emerging technologies

• Membrane Ion Exchange Chromatography

 Lower operating & capital investment costs

Expensive

• Magnetic fishing

• Aqueous two-phase separation

Should be recycled many times to reduce operational cost

Safe but costly Applied polymers are expensive due to their purity & food grade nature (i.e. dextrans) 37



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V. Product Formation Conventional technologies • Spray drying

Safety Depends on the toxicity of the materials involved in the process

• Freeze drying • Emulsions

Emerging technologies • Pulsed fluid bed agglomeration

Safe

Safety is the main obstacle • Nanoparticles

i.e. may alter the route of lipophilic compounds adsorption 39

Thank You for Your Attention!

Information:

Linkedin:

chemlab.gr phenoliv.com charisgalanakis.com https://www.iseki-food.net/sigs/sig5

Galanakis Laboratories Phenoliv AB Charis Galanakis Food waste recovery 40