Using a lot of phosphoric acid to clean the oil and then a special clay removes almost all of another harmful chemical in the final product.
Scientific Claim
The combination of high-dosage phosphoric acid during degumming and acid-activated bleaching earth is associated with near-complete elimination of glycidyl esters during palm oil refining.
Original Statement
“The combination of high dosage phosphoric acid during degumming with the use of acid activated bleaching earth eliminated almost all glycidyl esters during refining.”
Evidence Quality Assessment
Claim Status
overstated
Study Design Support
Design cannot support claim
Appropriate Language Strength
association
Can only show association/correlation
Assessment Explanation
The verb 'eliminated almost all' implies near-total causation, but without RCT controls or replication details, only association under specific conditions can be claimed.
More Accurate Statement
“The combination of high-dosage phosphoric acid during degumming and acid-activated bleaching earth is associated with near-complete reduction of glycidyl esters in refined, bleached, and deodorized palm oil under the tested conditions.”
Gold Standard Evidence Needed
According to GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this specific claim, ordered from strongest to weakest evidence.
Randomized Controlled TrialLevel 1bWhether this specific combination causes near-total elimination of glycidyl esters compared to other degumming/bleaching combinations.
Whether this specific combination causes near-total elimination of glycidyl esters compared to other degumming/bleaching combinations.
What This Would Prove
Whether this specific combination causes near-total elimination of glycidyl esters compared to other degumming/bleaching combinations.
Ideal Study Design
Double-blind RCT of 150 palm oil batches, randomized to: (1) high-dose phosphoric acid + acid-activated earth, (2) low-dose phosphoric acid + acid-activated earth, (3) high-dose + natural earth, (4) control; measuring glycidyl esters via LC-MS after deodorization, with n=37–38 per group.
Limitation: Cannot generalize to all crude palm oil types or global refining conditions.
Prospective Cohort StudyLevel 2bWhether this combination consistently results in glycidyl ester levels below detection limits across multiple industrial runs.
Whether this combination consistently results in glycidyl ester levels below detection limits across multiple industrial runs.
What This Would Prove
Whether this combination consistently results in glycidyl ester levels below detection limits across multiple industrial runs.
Ideal Study Design
Monitoring 500 consecutive refining batches using this combination, measuring glycidyl esters in final product, with crude oil quality and deodorization parameters recorded and adjusted for.
Limitation: Cannot isolate effect from other unmeasured process variables.
Case-Control StudyLevel 3Whether batches with detectable glycidyl esters are less likely to have used this combination.
Whether batches with detectable glycidyl esters are less likely to have used this combination.
What This Would Prove
Whether batches with detectable glycidyl esters are less likely to have used this combination.
Ideal Study Design
Comparison of 100 batches with detectable glycidyl esters (>0.1 ppm) vs. 100 with undetectable levels, matched for crude oil and deodorization, analyzing degumming and bleaching methods used.
Limitation: Retrospective design limits causal inference.
Evidence from Studies
Supporting (1)
The study found that using a lot of phosphoric acid in the first step and a special type of clay in the second step removed almost all harmful glycidyl esters from palm oil — exactly what the claim says.