BUKU ABSTRAK - Universiti Putra Malaysia

Food
Equilibrium Headspace Analysis of Volatile Flavour Compounds Extracted from Soursop (Annona
muricata) using Comprehensive Two-dimensional Gas Chromatography Time-of-flight Mass Spectrometry
(GC×GC-TOFMS) with Headspace Solid Phase Microextraction (HS-SPME)
Assoc. Prof. Dr. Tan Chin Ping
Kok Whye Cheong, Hamed Mirhosseini, Mahiran Basri, Azizah Osman, Nazimah Sheikh Abdul Hamid, Sung
Tong Chin and Yaakob Che Man
Faculty of Food Science and Technology, University Putra Malaysia,
43400 UPM Serdang, Selangor, Malaysia.
+603-8946 8418; tancp@putra.upm.edu.my
Headspace solid-phase microextraction (HS-SPME) coupled to comprehensive two-dimensional gas
chromatography time-of-flight mass spectrometry (GC×GC-TOFMS) was applied for equilibrium headspace
analysis of Malaysian soursop (Annona muricata) volatile flavor compounds. The influence of HS-SPME
variables, namely sample concentration, salt concentration and sample amount, on the equilibrium headspace
analysis of ten target volatile flavor compounds was investigated using response surface methodology (RSM). A
total of 135 compounds extracted using a CAR/PDMS fiber were successfully identified using GC×GC-TOFMS,
of which 37 compounds, comprising 20 esters, 6 alcohols, 3 terpenes, 2 acids, 2 aromatics, 2 ketones and 2
aldehydes, were identified as the main volatile aroma compounds of soursop flavour. The RSM results indicated
that all response-surface models were significantly (p < 0.05) fitted for ten target volatile flavor compounds, with
high R2 values ranging from 0.658 to 0.944. Multiple optimization results showed that extraction using a 76.6%
(w/w) sample concentration, 20.2% (w/w) salt and 8.2 g of blended soursop pulp was predicted to provide the
highest overall equilibrium headspace concentration for the target soursop volatile flavor compounds.
Keywords: Headspace solid-phase microextraction, two-dimensional gas chromatography, time-of-flight mass spectrometry,
equilibrium headspace analysis, soursop
Extraction and Development of Reduced-fat (RF) Mayonnaise from Coconut
Residue
Assoc. Prof. Dr. Tan Chin Ping
Siou Pei, Oi Ming Lai, Kamariah Long and Hamed Mirhosseini
Faculty of Food Science and Technology, University Putra Malaysia,
43400 UPM Serdang, Selangor, Malaysia.
+603-8946 8418; tancp@putra.upm.edu.my
Coconut residue (CR) obtained after the extraction of coconut milk is potentially a good source of dietary
fiber (DF), which mainly is cellulose and available in large quantities. In this study, dietary fiber contents of CR
were extracted, characterized and incorporated as a valuable ingredient into reduced-fat (RF) mayonnaise. Waterwashed
CR samples as well as the original samples were analyzed for their chemical composition, soluble dietary
fiber (SDF), insoluble dietary fiber (IDF) and total dietary fiber (TDF), and measurements were based on dry
matter. Fractionated IDF was further treated into four fractions: cellulose, lignin, hemicelluloses A and B. IDF,
TDF, moisture, crude fat, protein and CHO (carbohydrate) values were significantly (P < 0.05) different between
the samples. The TDF of the CR with treatment differed significantly (P < 0.05) between two different analytical
methods. The cellulose contents were 72.67% and 72.33% for TDF in original and water-washed CR samples,
respectively. The formulation of an oil-in-water (O/W) emulsion RF mayonnaise containing water, coconutbased
cellulose (acting as a fat replacer and stabilizer in the O/W emulsion) and soybean oil was optimized using
mixture design. Contour plots for physical properties were generated using the predictive model, and the optimal
region for physical properties in this study was based on a full-fat (FF) products parameter. The results revealed
that RF mayonnaise shows similarities with the FF products. Thus, this study shows a good potential of coconutbased
cellulose to be used as a fat replacer in RF mayonnaise.
Keywords: Coconut residue, cellulose, reduced-fat (RF), dietary fiber, mixture design
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