Nanotechnology for human food: Advances and perspective

Figures & data

Figure 1. Nanotechnology has uses in all areas of food science, including agriculture, food processing, security, packaging, nutrition, and neutraceuticals.

Table 1. Nanoresearch thematic areas relevant to agri-food systems.

S.No.	Nanoresearch area
1.	Nanoparticles
2.	Quantum dots
3.	Carbon nanotubes
4.	Dendrimers
5.	Fullerenes
6.	Biosensors
7.	Diagnostic kits
8.	Micro-electromechanical systems (MEMS)
9.	Biochips
10.	Microfluidics and nanofluidics
11.	Smart delivery systems
12.	Nanofiltration
13.	Nanofibres
14.	Nanoscale processes

Table 2. Some representative synthetic polymer-based nanocomposites and their enhanced material properties, method of processing, and level of incorporation.

Polymer	Nanomaterial	Method of processing	Enhanced material properties
Poly(vinyl alcohol) (PVA)	Cellulose nanocrystals (CNC)	Solvent casting	Tensile strength (TS) increased by up to 45%.
Poly(e-caprolactone) (PCL)	CNC	Film casting evaporation technique	Water vapour permeability (WVP)
Low-density polyethylene/linear low-density polyethylene (LDPE/LLDPE)	Nanoclay	Co-rotating twin screw extruding	Elastic modulus (EM) of LDPE/LLDPE
Polyethylene (PE)	Layered silicate	Micro-extruding	Crystallization temperature increased from 102°C to 111°C
Polypropylene (PP)/ethylene-propylene-diene rubber (EPDM) blend	Montmorillonite (MMT)-based organoclay	Melt extrusion	Adding 1.5 vol% organoclay increased both O2 and CO2 barrier properties
Maleated polyethylene	Silicate	Melt extrusion	The stiffness of the film increased with the addition of silicate filler
Ethylene-vinyl alcohol copolymer (EVOH)/poly(lactic acid) (PLA)	Clay	Melt blending	Barrier to oxygen enhanced with the addition of clay
PP	Silica	Extruding	TS and toughness increased with the addition of nanosilica
LDPE/LLDPE	MMT organoclay	Twin extruder moreover, then film blown	Oxygen permeability (OP) decreased by 50% with the addition of organoclay
Polyvinyl chloride (PVC)	Organoclay	Melt intercalation	TS increased by adding 3phr nanoclay
PVC/ethylene-vinyl acetate copolymer (EVA)	OMMT	Melt compounding	Impact strength improved
poly(ethylene-co-vinyl acetate) (EVA)	Nanosilica	Two-roll mixing	TS, hardness, and abrasion resistance increased by adding nanosilica
Unsaturated polyester (UP) and vinyl ester oligomer (VEO)	Organophilic MMT clay	Casting	TS of 10% VEO-toughened UP resin increased. Flexural strength increased by 19% and 41%, respectively, with the addition of the same amounts of organoclay
Poly(methyl methacrylate) (PMMA)	Layered silicate	Injection moulding	Tensile modulus increased by 35% compared to neat PMMA.
PP	Clay	Twin screw extruder	Oxygen transmission rate (OTR) reduced by 21.4% with 4% nanoclay.
			Water vapour transmission rate (WVTR) decreased by 28.1% with 2% nanoclay
Polyimide (PI)	Clay	Casting	A 3 wt% clay reduced gas permeability and oxygen permeability to less than half compared with neat PI
PI	Clay (Na ion-exchanged clays Naþ-saponite (SPT), Naþ-mica (Mica), and Naþ-MMT	Casting	Highest TS of 101 MPa was observed at 0.5 wt% clay. The initial modulus increased from 2.62 to 3.45 GPa as nanoclay content rose from 0 to 1.0 wt%
Polystyrene (PS)	Organo-montmorillonite Cloisite 20A (C20A)	Melt processing with twin screw extruding	Tensile, flexural, and impact strengths increased by 83%, 55%, and 74%, respectively by adding 5% clay
PP	Corn zein	Solution intercalation method	OP reduced by four times with nanocoating of PP films. WVP reduced by 30% by adding 5 wt. % OMMT
PI	Clay (Cloisite 30B)	Casting	OP of the film with 10 wt. % clay decreased by 95% (42 cc/m^2/day) compared with neat PI film (768 cc/m^2/day)
High-density polyethylene	Clay (MMT)	Melt mixing	OP decreased by 30% when 15% wt of clay was added
EVOH	Organically modified MMT	Casting	Oxygen and water vapour barrier properties increased by 59% and 90%, respectively with the addition of 3 wt% clay

Table 3. Comparisons between green revolution technologies and nanotechnology on their impacts and implications for food systems.

Features	Green revolution technologies	Nanotechnologies
Primary area of focus	Productivity of mainly cereal crops like wheat, rice, and maize	Productivity and management of crops and livestock by crop and livestock improvement, pest diagnosis and surveillance, food processing, safety, and packaging
Secondary area of focus	Nil	Vaccines, pesticides, fertilizers, water, gene, drug, remediation for natural resources, and other input delivery formulation in plants and animals, nanoarray-based gene expression in plants and animals under stress conditions
Applications	Crop input packages; improvement of plant architecture; genetic enhancement through conservative breeding	Areas of gene/DNA delivery, expressionssequencing, therapy, regulation: DNA targeting, extraction, hybridization, fingerprints for DNA; RNA detection, cell probes, cell sorting, and bioimaging
Regulatory system	Not warranted	Developing but still not in practice in many places
Parties in technology development and dissemination	Public sector	Large- and small-scale industry, venture, capital funds
Research skills required	Plant breeding and other agricultural sciences	New knowledge and skill set in addition to conventional; new workforce to be created
Environment risks	Evidence for several negative effects on natural resources	Data still not available
Public acceptance	Whole world has accepted	Preliminary protests by civil societies