Clitoria ternatea is a herbaceous plant with many health benefits. Extraction is crucial to obtain its bioactive components which contribute to its antioxidant properties. Therefore, this study was conducted to find an optimum extraction condition of C. ternatea flower on total phenolic content (TPC) and antioxidant activity (2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical-scavenging activity) as well as to determine its total flavonoid content (TFC) and anthocyanin content based on the optimum extraction condition generated by Response Surface Methodology (RSM)-Design Expert 7.1.5. TPC, TFC and total anthocyanin of C. ternatea were conducted by Folin Ciocalteu (FC), calorimetric assay and pH differential method, respectively. The ranges of selected independent variables were ethanol concentration (30°C–90% v/v), time (60–120 min) and temperature (30°C–70°C). The optimum extraction condition was obtained at 39.62% v/v ethanol concentration, 90 min and 44.24°C. However, these values were slightly adjusted according to the convenience of equipment to operate in which ethanol concentration was adjusted to 37% v/v, time remain at 90 min and temperature at 45°C. The predicted values of TPC and DPPH radical scavenging activity were 41.60 mg GAE/g dry samples and 68.12% inhibition and were experimentally verified to be 41.17 ± 0.5 mg GAE/g dry samples and 63.53 ± 0.95% inhibition of TPC and DPPH radical scavenging activity respectively. This result has showed RSM can optimise TPC and radical scavenging activity of C. ternatea . Upon the optimum condition, the TFC determined was 187.05 ± 3.18 mg quercetin/g dried sample which was higher than TPC and the total anthocyanin content was 28.60 ± 0.04 mg/L. Hence, the extractable phenolic, flavonoid and anthocyanin compounds indicated that C. ternatea is a good source of natural antioxidant.

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Essential oils have a long history in their variety of applications. Although essential oils of various herbs and spices from other parts of the world have shown antimicrobial effects, those from Malaysian herbs remain underreported. Thus, can be further utilized in the search for novel bioactive compounds as natural antimicrobials to fulfil the consumers' demand for safer, healthier, and higher‐quality foods with longer shelf life. In the present work, the essential oils from ten herbs and spices namely betel, cinnamon, clove, coriander, galangal, ginger, lemongrass, lime, nutmeg, and turmeric, selected based on their abundance and economic importance, were analysed by gas chromatography and mass spectrometry. A total of 120 bioactive compounds were detected. The major (>10%) bioactive compounds were anethole, 26.25% (betel), cinnamaldehyde, 63.39% (cinnamon), eugenol, 87.16% (clove), linalool, 54.79% (coriander), propenoic acid, 29.56% (galangal), α-zingiberene, 26.32% (ginger), geranial, 42.61% (lemongrass), limonene, 39.84% (lime), β-phellandrene, 27.80% (nutmeg), and ar-turmerone, 41.81% (turmeric). All essential oils also yielded minor (<10%) bioactive compounds of different classes. Some of these major and minor bioactive compounds have been reported to exert fungicidal/fungistatic effects and could be an excellent candidate in the development of efficient fungal spoilage control strategies such as an active food packaging system.

This study aims to produce stable essential oil nanoemulsions (EONEs) of betel and pandan leaves as functional ingredients in food applications. EONEs from betel leaf (Piper betel Linn.), pandan leaf (Pandanus amaryllifolius Roxb.), and a blend of betel/pandan leaf at 1:1 (v/v) were produced using the spontaneous emulsification (SE) method. The oil phase [5% (v/v) (essential oil (EO) and corn oil at the ratio 4:1)] was mixed with an aqueous phase [mixture of 15% (v/v) Tween 80 in 80% (v/v) distilled water] using magnetic stirring at 750 rpm at 25 °C. The particle size, polydispersity index (PDI), zeta (ζ) potential, particle size distribution (PSD), turbidity, morphology, antioxidant activity, in vitro digestibility, and physical stability of the EONEs were then investigated. Betel/pandan leaf EONE had the smallest size (24 nm), highest ζ potential (−33 mV), and lowest turbidity (86.66% transmittance), while betel leaf EONE exhibited the lowest PDI (0.23). From the transmission electron microscopy (TEM) micrographs, all EONEs were composed of spherical particles with sizes in the range of 20–100 nm. The betel leaf EONE showed the highest 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity (88.01%) followed by betel/pandan leaf EONE (79.24%) and pandan leaf EONE (43.12%). Betel/pandan leaf EONE showed the highest in vitro digestibility by exhibiting the highest free fatty acid (FFA) released. Betel leaf EONE appeared to be the most physically stable after 8 weeks of storage at 4 °C. Overall, nanoemulsions containing betel leaf EO showed great potential as functional ingredients for food applications as they exhibited small particle size, low turbidity and PDI, narrow PSD, high antioxidant activity, and physical stability.