- Synthesis of (Z)-3-hexen-1-yl butyrate in hexane and solvent-free medium using Mucor miehei and Candida antarctica lipases
-
(Z)-3-Hexen-1 -yl butyrate is an important flavor and fragrance compound as it represents the model of a natural herbaceous (green) note. Two immobilized lipases from Mucor miehei (Lipozym IM) and from Candida antarctica (Novozym 435) were investigated for their use in the synthesis of (Z)-3-hexen-1-yl butyrate by direct esterification in n-hexane. To determine optimal conditions for esterification, we examined the following parameters: temperature, amount of lipase, acid/alcohol ratio, and absence of solvent. In n-hexane, bioconversion yields reached 95 (after 4 h) and 92% (after 6 h) for, respectively, Lipozym IM [17 (w/w reactants)] and Novozym 435 [2% (w/w reactants)]. In the absence of solvent, at 60 °C, Novozym 435-catalyzed esterification afforded the title compound in 80% yield. Up to 250 g (in hexane) and 160 g (without solvent) of ester were easily prepared, in a single operation, at a laboratory scale, in few hours, using 2% (w/w reactants) lipase.
- Bourg-Garros,Razafindramboa,Pavia
-
-
Read Online
- Rape seedling lipase catalyzed synthesis of flavor esters through transesterification in hexane
-
Butyl butyrate, a short-chain ester with fruity pineapple odor, is a significant flavor compound that is widely used in the food industry. Enzymatic synthesis of butyl butyrate by crude rape seedlings lipase has been investigated in n-hexane using 50 g/L of enzyme at 40 °C through alcoholysis of ethyl butyrate with butanol. The influence of reaction parameters such aswater content, water activity, substrate concentrations and reaction time were also studied. Ester yield of 60% after 96 h has been obtained with 0.5% (v/v) of added water using reversible reaction or activated ester. A concentration of 0.1M of butanol while 0.6 M of ethyl butyrate was found optimal for butyl butyrate synthesis. The esterification catalyzed by lipase was inhibited by increasing the butanol concentration beyond 0.10 M while no inhibition of enzyme was observed with ethyl butyrate. (Z)-3-hexen-1-ol (cis-3-hexen-1-ol) esters posses the odour of freshly cut grass and are used to obtain natural green top notes in food flavours. Two different approaches for rapeseed lipase catalyzed synthesis of these flavour esters were also studied. Acylation of (Z)-3-hexen-1-ol with vinyl acetate (irreversible acyl donor) and butyl caproate (reversible acyl donor) was evaluated. Ester yield of 99 % after 24 h was obtained for (Z)-3-hexen-1-yl acetate with vinyl acetate as acyl donor. Crude rape seedlings lipase has proved to be an efficient catalyst to obtain (Z)-3-hexen-1-ol esters using irreversible acyl donor such as vinyl ester in hexane. Crude lipase also works well at ambient temperature without need of immobilization.
- Liaquat, Muhammad,Khan, Saeed,Aslam, Sher,Khan, Ayub,Khan, Hakim,Khan, Shah Masaud,Ali, Sardar,Wahab, Said,Bhatti, Haq Nawaz
-
body text
p. 144 - 150
(2012/05/19)
-
- Rapeseed lipase catalyzed synthesis of butyl butyrate for flavour and nutraceutical applications in organic media
-
Butyl butyrate, a short chain ester with fine fruity pineapple odour, is a significant flavour compound. Recent investigations show that butyrate esters also have anticancer activity. Factors influencing the synthesis of butyl butyrate by organic phase biocatalysis were investigated. Maximum ester yield of 89% was obtained when 0.25 M butanol and butyric acid were reacted at 25 °C for 48 h in the presence of 250 mg rape seed lipase acetone powder in hexane. Addition of water did not affect synthesis, while a water activity of 0.45 was found optimum. Of 15 different alcohols evaluated, isoamyl and (Z)-3- hexen-1-ol were esterified most effectively with molar conversion yields of 92.2 and 80.2%. Short chain primary alcohols such as methanol and medium-long chain alcohols, such as heptanol and octanol were esterified more slowly. The results show that rape seed lipase is versatile catalyst for ester synthesis with temperature stability range 5-50 °C.
- Liaquat, Muhammad
-
experimental part
p. 6 - 13
(2012/06/18)
-
