Flavour Characyerisation and Stabilisation of Fresh, Spray-Dried and Encapsulated Durian Extract
This study concerned the characterisation and stability of flavour volatiles from fresh, spray-dried, freeze-dried and encapsulated durian powder. In the first part of this study, headspace solid phase microextraction (SPME) coupled to fast gas chromatographymass spectrometry (GC-MS) was applied...
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| Format: | Thesis |
| Language: | English English |
| Published: |
2006
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/6731/1/FSTM_2006_15.pdf |
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| Summary: | This study concerned the characterisation and stability of flavour volatiles from fresh,
spray-dried, freeze-dried and encapsulated durian powder. In the first part of this study,
headspace solid phase microextraction (SPME) coupled to fast gas chromatographymass
spectrometry (GC-MS) was applied to analyze the volatile compounds of durian
varieties D2, D24, and Dl01 from Malaysia. Sampling sensitivity was improved by
evaluation of sample matrix, sampling size, headspace volume, salt addition and
sampling duration. A total of 39 volatile compounds were identified in fresh durian pulp
comprising 22 esters, 9 sulfur-containing alkanes, 3 thioacetals, 2 thioesters, 2 thiolanes,
and 1 alcohol. The relative amount of volatiles estimated using lppm internal standard,
revealed differences in the volatile composition among varieties. Further classification
and characterisation of each durian variety was successfully conducted using Principal
Component Analysis (PCA) whereby PCl, which explained 35.36% of variance,
distinguished variety 0 2 from 024 while PC2 with 22.10% variance explained,
separated the cluster of variety Dl01 from 024.Consequently, quantification of the major flavour volatiles in durian (Durio zibethinus)
that included propanethiol, ethyl propanoate, propyl propanoate, ethyl 2-
methylbutanoate (E2MB) and diethyl disuIfide, from fresh, freeze-dried and spray-dried
durian pulp as well as effect of drying on the volatiles composition of durian pulp was
evaluated using SPME coupled to fast chromatography-time-of-flight-mass
spectrometry (fast GC-TOFMS). The correlation coefficients for target volatiles were
improved (over 0.97) when surrogate internal standard was used with precision that
ranged between 2 and 14%. Overall, spray-drying process, which employed high
temperature, induced the formation of several volatiles that included aldehyde, ketone,
furan and pyrrole. The loss of flavour volatiles in freeze-dried and spray-dried pulp
ranged from 71 to 97% and 97 to 99% respectively.
Finally, changes in durian volatile composition and stability of the major volatile
compounds (propanethiol, ethyl propanoate, E2MB and diethyl disulfide) in the spray
dry microencapsulated durian powder using 3 types of coating matrices (maltodextrin,
gum arabic and lipophilic starch) were evaluated. The flavour release characteristic
from the microcapsules stored under different relative humidity, RH (44%, 75% and
92%) at 50°C was further studied. Stability of the microcapsule produced was
maintained throughout 20 days of storage without liberation of any volatile acid.
Formation of volatiles that included 2- and 3-methylbutanal, 1-ethyl-1-H-pyrrole
compounds were induced during the process. Microcapsules prepared from a blend of
maltodextrin and gum arabic at ratio 3:1 showed higher volatiles retention. Low
volatiles retention in N-Lok microcapsule was observed which probably caused by the cracking on the surface of its microcapsule. Furthermore, volatiles were released from
MG microcapsule at the rate according to Avrami's equation which increased with
higher relative humidity in the storage atmosphere. |
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