THE CONFERENCE PROCEEDINGS - IFEAT

BIOCONVERSION OF COCONUT OIL AND PALM KERNEL OILTO AROMA-ACTIVE ESTERSBoth coconut oil and palm kernel oil are rich infatty acids of C8-C14 (~70%). There is atremendous potential to unlock the value of C8-C14 fatty acids as aroma chemicals, especiallyaroma-active esters. Lipase-catalysed conversionof coconut oil and palm kernel oil into esters is asimple one-step reaction: alcohols + oil " esters.This creates an opportunity to build a library ofnatural esters by exploiting naturally producedalcohols of short- to medium-chain carbons suchas methanol, ethanol and propanol. One sourceof natural alcohols is fusel oil (also known asfusel alcohols or higher alcohols), which ismainly composed of active amyl and isoamylalcohols and is a by-product of the alcoholdistillation industry. Theoretically, 20-30 aroma-active esters can be generated by using alcohols ofappropriate carbon chain length.THE BIOPRODUCTS – ESTER EXAMPLESQuantitatively lauric acid (C12) is the major fatty acid, followed by myristic acid (C14), in coconut oiland palm kernel oil. As such, it is imperative to unlock their value as aroma compounds from theperspective of yield and cost-effectiveness. Due to the relatively longer carbon chain length of the twofatty acids, the carbon chain length of alcohols to be paired with the oil is critical so that the estersgenerated can be sufficiently volatile to be odour-active. Two examples of such alcohols are methanoland ethanol. Other alcohols such as aromatic alcohol (e.g. 2-phenylethanol) and branched-chainalcohol (e.g. active amyl and isoamyl alcohols) may also be used to exploit the value of the shorterchainfatty acid octanoic acid (C8) as aroma chemicals.By pairing methanol and ethanol with coconut oil or palm kernel oil, methyl and ethyl laurate as wellas methyl and ethyl myristate are produced as quantitatively the major esters, in addition to othermethyl and ethyl esters. Methyl and ethyl laurateimpart various flavour notes such as coconut,waxy, sweet, floral or green. Methyl and ethylmyristate possess sweet, petal, waxy or violetnotes. On the other hand, by selecting isoamylalcohol or 2-phenylethanol, the odour-activeesters isoamyl octanoate and 2-phenylethyloctanoate are generated. Isoamyl octanoate givessweet, fruity, green, pineapple, coconut orcognac odours, whereas the odour of 2-phenylethyl octanoate is described as sweet,fruity, floral, winey or cognac-like. All theseesters have applications in flavour, fragrance andcosmetics.Bioconversion of coconut oil and palmkernel oil to aroma-active esters• Rich in fatty acids of C8-C14 (>50%)• Potential to unlock value of C8-C14 as aromachemicals• Enzymatic conversion to esters: alcohols + oil!esters (one-step reaction)• Potential to build a library of natural esters – byselecting alcohols of C1-C5• 20-30 aroma-active esters can be generatedThe bioproducts – ester examples• Methyl and ethyl laurate – coconut nut, waxy, sweet,floral, green• Methyl and ethyl myristate – sweet, petal, waxy,violet• Isoamyl octanoate - sweet, fruity, green, pineapple,coconut, cognac• 2-Phenylethyl octanoate - sweet, fruity, floral, winey,cognac-like• Applications – flavour, fragrance, cosmetics190