Researchers Find Ways to Reduce Acrylamide in Table Olives

The concentration of the compound, which is carcinogenic, can be impacted by the maturation stage, length of storage period and type of washing treatment.
By Jasmina Nevada
Aug. 23, 2021 09:31 UTC

A recent study con­ducted by Extremadura’s provin­cial gov­ern­ment in Spain has iden­ti­fied some strate­gies to mit­i­gate the pres­ence of acry­lamide dur­ing the indus­trial pro­cess­ing of black olives.

Acrylamide is a com­pound found in car­bo­hy­drate-rich foods after being heated. The International Agency for Research on Cancer con­sid­ers the com­pound car­cino­genic.

The study pro­vides dif­fer­ent strate­gies that, with­out impos­ing any addi­tional cost in its man­u­fac­ture, upgrade the pro­cess­ing of Californian-style black ripe olives by remov­ing acry­lamide from the final prod­uct.- Daniel Martín-Vertedor and Antonio Fernández, researchers, Junta de Extremadura

According to the researchers, acry­lamide gen­er­a­tion in table olives is evi­dent in larger quan­ti­ties in Californian-style black ripe olives. The com­pound devel­ops as a result of oxi­da­tion after ther­mal ster­il­iza­tion occurs dur­ing the table olive pro­duc­tion process.

The amount of acry­lamide in table olives is depen­dent on many fac­tors such as how olives are processed, ther­mal ster­il­iza­tion con­di­tions, pack­ag­ing meth­ods that may or may not involve the use of brine and cook­ing.

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The researchers con­ducted their study using Hojiblanca olives, a com­mon Spanish vari­ety with an inter­me­di­ary level of acry­lamide con­tent.

By chang­ing dif­fer­ent phases of the pro­duc­tion process – olive mat­u­ra­tion stage, length of stor­age period and type of wash­ing treat­ment – the researchers were able to lower lev­els of acry­lamide and thus improve the qual­ity of the table olives.

Applying these mit­i­ga­tion mea­sures at indus­trial scale, black table olives con­sumers will intake a sig­ni­fica­tively minor quan­tity of this toxic com­pound,” Daniel Martín-Vertedor and Antonio Fernández, the two lead researchers on the project, told Olive Oil Times.

Therefore, this type of table olive elab­o­ra­tion can be more present in the human diet, tak­ing advan­tage of the ben­e­fits of table olives,” they added.

The researchers used olives har­vested at two dif­fer­ent points of mat­u­ra­tion: the green and yel­low-green stages. Olives har­vested at the yel­low-green mat­u­ra­tion stage – when they are one step closer to verai­son – had higher lev­els of acry­lamides.

Furthermore, green olives stored for 21 months pre­sented the low­est acry­lamide lev­els. Acrylamide lev­els also low­ered by 18 per­cent when the olives were sprayed with water before rins­ing. Washing the olives with water heated to 25 ºC for 40 min­utes also led to a 36-per­cent reduc­tion in the chem­i­cal.

However, fol­low­ing treat­ment with lye, which is com­monly used to remove the com­pound respon­si­ble for the bit­ter taste of table olives, acry­lamide lev­els increased. Pitted olives retained the low­est lev­els of the chem­i­cal, fol­lowed by unpit­ted olives and sliced olives.

The researchers fur­ther found that table olives canned in brine with higher con­cen­tra­tions of salt after the pro­duc­tion process also increased the acry­lamide con­tent. However, this was not observed in olives stored in other liq­uids.

The study pro­vides dif­fer­ent strate­gies that, with­out impos­ing any addi­tional cost in its man­u­fac­ture, upgrade the pro­cess­ing of Californian-style black ripe olives by remov­ing acry­lamide from the final prod­uct and, con­se­quently, tak­ing care of the con­sumer’s health and diet,” Martín-Vertedor and Fernández said.

The two researchers added that the impact of pack­ag­ing on acry­lamide con­tent was a sep­a­rate vari­able that requires fur­ther study to under­stand bet­ter.

Both in the process and the com­mer­cial­iza­tion, the pack­ag­ing is a steady fac­tor in the acry­lamide for­ma­tion as can be seen in the results of the arti­cle,” Martín-Vertedor and Fernández said. There will be a future study in which the con­tainer is eval­u­ated as another pos­si­ble vari­able in the acry­lamide gen­er­a­tion.”

In a 2019 study, the two researchers found that the addi­tion of phe­no­lic com­pounds, includ­ing hydrox­y­ty­rosol, and olive leaf extract before the ster­il­iza­tion stage also decreased the acry­lamide con­tent from the final prod­uct.

Martín-Vertedor con­cluded that lim­its on the amount of acry­lamide present in table olives should be estab­lished. Baseline lev­els of the com­pound in Hojiblanca olives mea­sure at 254 micro­grams per kilo­gram but are nearly dou­ble that in Manzanilla de Sevilla.

We con­sider that the min­i­mum lev­els of acry­lamide in table olives mar­keted should be set at val­ues closer to 300 micro­grams per kilo­gram, thus guar­an­tee­ing the health of table olive con­sumers at an inter­na­tional level,” he said.


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