Process development for higher yield production of diacylglycerol oil via partial hydrolysis
The disclosure of diacylglycerol (DAG) oil to replace the conventional edible oils has received increasing interest among researchers and food manufacturers owing to its anti-obesity properties. Distinct processing approaches have been proposed to produce DAG-enriched oil in which enzymatic pa...
Saved in:
Main Author: | |
---|---|
Format: | Thesis |
Language: | English |
Published: |
2015
|
Subjects: | |
Online Access: | http://psasir.upm.edu.my/id/eprint/71268/1/IB%202015%2036%20IR.pdf http://psasir.upm.edu.my/id/eprint/71268/ |
Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
Institution: | Universiti Putra Malaysia |
Language: | English |
Summary: | The disclosure of diacylglycerol (DAG) oil to replace the conventional edible oils
has received increasing interest among researchers and food manufacturers
owing to its anti-obesity properties. Distinct processing approaches have been
proposed to produce DAG-enriched oil in which enzymatic partial hydrolysis
outstands other methods due to its inexpensive raw materials and single-step
hydrolytic reaction involved. In present work, single-factor optimization of partial
hydrolysis for DAG production from refined, bleached, deodorized palm oil
(RBDPO) catalysed by immobilized Rhizomucor miehei lipase (Lipozyme RMIM)
was carried out in batch system. Effects of four operating parameters namely
temperature, enzyme dosage, water content and agitation speed were
investigated. Optimum production conditions for palm based-DAG are as follows:
temperature = 55oC, enzyme dosage = 10-wt%, water content = 5-wt% and
agitation speed = 500 rpm. A DAG yield of 31-wt% was obtained after 6 h of
reaction. The partial hydrolysis reaction was found to conform to Ping-Pong Bi-Bi
with substrate inhibition mechanism. The optimum operating conditions were
then applied to the lab-scale packed bed system.
Packed bed reactor (PBR) is an effective reactor configuration because it
enables reusability of the enzyme particles besides enhancing its operational
stability. However, mass transfer limitation remains a key challenge in packed
bed column system, especially at large scale. A dimensionless mathematical
mass transfer model of Colburn factor, JD, which is a function of Reynolds (Re)
and Schmidt (Sc) numbers, was therefore developed to simulate mass transfer
phenomena of the reaction mixture in PBR during enzymatic partial hydrolysis
reaction. The results revealed that the mass transfer correlation of JD=0.92(Re)-
0.2 was able to predict the experimental data accurately. In addition, response
surface methodology (RSM) was employed to optimize the process variables namely packed bed height and substrate flow rates on DAG production in PBR.
Quadratic models were successfully developed for both DAG and unhydrolyzed
triacylglycerol (TAG) with insignificant lack of fit (P>0.05). Optimum conditions for
DAG synthesis were evaluated to be 10 cm packed bed height and 3.8 ml/min
flow rate with 29-wt% DAG being reported. Immobilized enzyme can be reused
up to 10 times without significant loss in enzymatic activity.
The present study also investigated the production efficiency using columns with
different length-to-diameter ratios (L/D ratio) to determine the most potential
process setup for industrial DAG manufacturing. Practical design issues such as
operating temperature, substrate flow rate and reaction time were evaluated with
respect to various packed bed column configurations. A column dimension with
L/D ratio of two was determined to be the most suitable bed column design for
lipase-mediated partial hydrolysis reaction. The optimal reaction temperature,
substrate flow rate and residence time for the production of DAG in packed bed
column dimension of two were found to be 55oC, 5 ml/min and 5.8 min,
respectively. Under these operating conditions, a maximal DAG content of 35-
wt% was obtained within the first 2 h. Since scientific knowledge is lacking in the
employment of PBR for the production of DAG-enriched oil via enzyme-catalysed
partial hydrolysis, the findings of the study would facilitate the design of a pilotscale
fixed bed reactor system for lipase-mediated partial hydrolysis to obtain
DAG-enriched oil as functional oil without constraints. |
---|