Olive Oil-Based Films May Soon Replace Plastic Food Packaging

New research shows that extra vir­gin olive oil might be effi­ciently used as a key com­po­nent of ole­ofilms, envi­ron­men­tally friendly food pro­tec­tive coat­ings.

According to the Turkish researchers who authored the study, these new mate­ri­als could become a viable alter­na­tive to plas­tics in food pack­ag­ing.

The researchers devel­oped a sim­ple and effec­tive method to pro­duce ole­ofilms, bring­ing the mate­ri­als one step closer to com­pet­ing with cur­rent indus­try stan­dards.

“Conventional plas­tic films are durable for a long time and ensure reli­a­bil­ity dur­ing trans­porta­tion and stor­age,” Bülent Başyiğit, a researcher at the Harran University’s fac­ulty of engi­neer­ing in Şanlıurfa, Turkey, told Olive Oil Times.

“Some of their other advan­tages include being low cost, light­weight, easy to process and hav­ing advanced bar­rier prop­er­ties,” he added. ​“However, petro­leum-derived con­ven­tional plas­tic films do not biode­grade and remain in nature for a long time.”

“Moreover, harm­ful chem­i­cals found in the nat­ural struc­ture of the con­ven­tional plas­tic films might leak into the pack­aged food prod­ucts or bev­er­ages,” Başyiğit noted.

Based on biodegrad­able and edi­ble oil poly­mers, ole­ofilms may have a sig­nif­i­cant edge over plas­tics.

“Their most notable fea­tures are that they decom­pose quickly in nature and thus do not cause seri­ous envi­ron­men­tal pol­lu­tion,” Başyiğit said. ​“Oleofilms reduce car­bon foot­print by reduc­ing depen­dence on fos­sil fuels.”

Typically, plas­tic films are made from syn­thetic poly­mers derived from fos­sil fuels, such as poly­eth­yl­ene or polypropy­lene.

In addi­tion, pro­duc­ing such plas­tic films is a highly energy-inten­sive process, yet economies of scale have made it sig­nif­i­cantly cost-effec­tive, unlike most other indus­trial sec­tors.

Oleofilms’ key advan­tages over other biodegrad­able films are their elas­tic­ity and flex­i­bil­ity. They are also far more sta­ble when sub­jected to extreme tem­per­a­ture changes.

According to the researchers, the chem­i­cal struc­ture of ole­ofilms sig­nif­i­cantly reduces the risk of chem­i­cal leak­age into food or drinks.

Oleofilms do not dis­solve or break down eas­ily when exposed to mois­ture, and water does not eas­ily pass through them. ​“Oleofilms are water-resis­tant, and their water per­me­abil­ity is low,” Başyiğit con­firmed.

“Oleofilms may serve as promis­ing sys­tems for pro­vid­ing pro­tec­tion, par­tic­u­larly for oily and moist food prod­ucts, since they con­sist of films made from hydropho­bic and oil-based com­po­nents,” he said.

“These films can pro­long the shelf life of foods by pre­vent­ing oxi­da­tion, reduc­ing mois­ture loss and form­ing a water­proof bar­rier,” he added.

Some foods eas­ily pack­aged with ole­ofilms include choco­late-based prod­ucts, cheeses, processed meats and crack­ers.

In addi­tion, they prove to be highly effec­tive in pro­tect­ing fresh foods such as fruits and veg­eta­bles.

“One pri­mary rea­son for struc­tural dete­ri­o­ra­tion in fruits and veg­eta­bles is water removal from their struc­tures,” Başyiğit said. ​“Given the hydropho­bic nature of ole­ofilms, they are expected to main­tain the mois­ture bal­ance within the pack­age.”

“Thus, these film mod­els may help pre­vent shrink­age and hard­en­ing by reduc­ing water loss in all fruits and veg­eta­bles,” he added. ​“Natural oils, such as olive oil, pos­sess antimi­cro­bial and anti-fun­gal prop­er­ties that help slow food spoilage by inhibit­ing the growth of bac­te­ria and fungi.”

Extra vir­gin olive oil is a key com­po­nent of the ole­ofilm pro­duc­tion method devel­oped by the research team, which has proven more effi­cient than other biodegrad­able oils.

“Olive oil pro­vides antiox­ida­tive activ­ity to the final prod­uct due to the unique struc­tures it con­tains,” Başyiğit said, hint­ing at the pres­ence of toco­pherols (vit­a­min E) and phe­no­lic com­pounds in extra vir­gin olive oil.

“Their pres­ence in olive oil is cru­cial for pre­vent­ing or delay­ing poten­tial oxi­da­tion in films,” he added. ​“Preventing or delay­ing oxida­tive dete­ri­o­ra­tion enhances the lifes­pan of pack­ag­ing films.”

Extra vir­gin olive oil was iden­ti­fied as more effi­cient than other oils due to its high con­tent of monoun­sat­u­rated fatty acids, mainly oleic acid, which offers enhanced pro­tec­tion against oxi­da­tion com­pared to polyun­sat­u­rated fatty acids.

“Oils rich in sat­u­rated and polyun­sat­u­rated fatty acids can lead to the hard­en­ing or soft­en­ing of ole­ofilms,” Başyiğit said. The bal­anced unsat­u­rated fat con­tent of extra vir­gin olive oil makes it a more effi­cient choice.

Phenols and toco­pherols in olive oil reduce oxida­tive dam­age, a qual­ity that can be extended by ole­ofilms coat­ing.

“Incorporating extra vir­gin olive oil in ole­ofilms may enhance the antiox­i­dant prop­er­ties of the final prod­ucts,” Başyiğit said. ​“Moreover, antiox­i­dant com­pounds may pro­tect by dif­fus­ing through the film into the food.”

“Films con­tain­ing olive oil can extend shelf life, pre­serve nutri­tional qual­ity and pre­vent oxida­tive dete­ri­o­ra­tion by increas­ing the antiox­i­dant capac­ity of both the film mate­r­ial and the coated prod­uct,” he added.

The pres­ence of extra vir­gin olive oil in ole­ofilms fur­ther enhances their biodegrad­abil­ity.

“Oleic acid, phe­no­lic com­pounds and toco­pherols in olive oil can enhance biodegra­da­tion,” Başyiğit said. ​“Phenolic com­pounds can facil­i­tate degra­da­tion by increas­ing enzy­matic reac­tions for microor­gan­isms.”

The olive oil-based ole­ofilms were pro­duced by com­bin­ing pro­teins and lipids using ultra­sonic emul­si­fi­ca­tion tech­niques. The process uses high-fre­quency sound waves to cre­ate and sta­bi­lize emul­sions, mix­tures of two unmix­able liq­uids.

The pro­duc­tion began with the prepa­ra­tion of oleogels, which con­tain soy pro­tein hydrolysate, gelatin, extra vir­gin olive oil, stearic acid and lecithin.

The pro­tein and lipid phases were mixed in a one-to-one ratio and sub­jected to high-power son­i­ca­tion, which agi­tates par­ti­cles in a fluid through high-fre­quency sound waves (ultra­sound).

This process enhanced the sta­bil­ity and homo­gene­ity of the emul­sion. Once the oleogels were formed, they were com­bined with glyc­erol to improve flex­i­bil­ity.

After an ultra­sonic degassing process to elim­i­nate air bub­bles, the mix­ture was left to dry at room tem­per­a­ture for 24 hours.

The result­ing ole­ofilms, with thick­nesses between 0.18 and 0.25 mil­lime­ters, proved water-resis­tant with low gas per­me­abil­ity, mean­ing that oxy­gen, car­bon diox­ide, or water vapor could not eas­ily cross the bar­rier.

The method iden­ti­fied the nec­es­sary ultra­sonic power for opti­mal flex­i­bil­ity, strength and bar­rier prop­er­ties, which were suc­cess­fully tested on freshly cut pineap­ples.

“In films con­tain­ing hydrophilic and hydropho­bic struc­tures, ultra­sonic emul­si­fi­ca­tion is a vital tech­nique that improves film qual­ity by fos­ter­ing homo­gene­ity,” Başyiğit explained. ​“It pre­vents phase sep­a­ra­tion and enables the cre­ation of mechan­i­cally robust and func­tional films that main­tain sta­bil­ity over pro­longed peri­ods.”

Researchers warned that more invest­ment and research are needed to sup­port the fur­ther devel­op­ment of ole­ofilms and turn them into a com­mer­cially viable alter­na­tive to con­ven­tional plas­tic-based films.

The researchers added that sig­nif­i­cant chal­lenges still need to be addressed.

Oleofilms are more sus­cep­ti­ble to tear­ing than the cur­rent indus­try stan­dard and can­not yet com­pete in mechan­i­cal strength and flex­i­bil­ity. Vacuum pack­ag­ing is cur­rently not fea­si­ble with these new films either.

“Although mass pro­duc­tion of plas­tics is well estab­lished and their costs remain very low, ole­ofilms have yet to achieve economies of scale,” Başyiğit said. ​“In the long term, if these chal­lenges are over­come, ole­ofilms could serve as an envi­ron­men­tally friendly alter­na­tive.”

The next step for the researchers is to scale up its use in food pack­ag­ing and explore other pos­si­ble appli­ca­tions.

“In the long term, the inte­gra­tion of ole­ofilms into bio­med­ical appli­ca­tions is also pos­si­ble,” Başyiğit said. ​“In this con­text, they might be used in appli­ca­tions like drug deliv­ery sys­tems and wound dress­ings.”

“However, it is cru­cial to con­duct stud­ies to enhance the ther­mal and mechan­i­cal prop­er­ties of ole­ofilms to match those of petro­leum-derived films,” he con­cluded.