Yin Yin Thoo

Antioxidant synergism between ethanolic Centella asiatica extracts and α-tocopherol in model systems

The synergistic antioxidant effects of ethanolic extracts of Centella asiatica (CE), and α-tocopherol have been studied. The types of interactions exhibited by CE and α-tocopherol combined at different ratios were measured using three assays: 2,2-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS) radical-scavenging capacity, the β-carotene bleaching system and liposome peroxidation assays. Fixed-fraction isobolographic analysis was used to detect any inducement of the antioxidant activity compared with the individual activities of CE and α-tocopherol. Of all synergistic combinations of CE and α-tocopherol, only fraction 2/3 showed the synergistic combination that fits well in three different assays and can be explained by the regeneration of α-tocopherol by CE despite the interaction effect of β-carotene present in the analytical assay. This phenomenon involved complex interactions between CE and α-tocopherol to exhibit different degrees of interactions that eventually increased antioxidant activity.

Ultrasound-Assisted Extraction of Antioxidants in Misai Kucing (Orthosiphon stamineus)

Ultrasound-assisted extraction (UAE) with ethanol was used to extract the compounds responsible for the antioxidant activities of Misai Kucing (Orthosiphon stamineus). Response surface methodology (RSM) was used to optimize four independent variables: ethanol concentration (%), amplitude (%), duty cycle (W/s) and extraction time (min). Antioxidant compounds were determined by total phenolic content and total flavonoid content to be 1.4 g gallic acid equivalent/100 g DW and 45 g catechin equivalent/100 g DW, respectively. Antioxidant activities were evaluated using the 2,2-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS•+) radical scavenging capacity assay and the 2,2-diphenyl-1-picrylhydrazyl (DPPH•) radical scavenging capacity assay to be 1,961.3 and 2,423.3 µmol Trolox Equivalent Antioxidant Capacity (TEAC)/100 g DW, respectively. Based on the optimal conditions, experimental values were reported to be close to the predicted value by RSM modeling (p > 0.05), indicating the suitability of UAE for extracting the antioxidants of Misai Kucing. Rosmarinic acid, kaempferol-rutinoside and sinesetine were identified by high performance liquid chromatography-mass spectrometry.

Optimal Binary Solvent Extraction System for Phenolic Antioxidants from Mengkudu (Morinda citrifolia) Fruit

Antioxidants have been widely used in the food industry to enhance product quality by preventing oxidation of susceptible substances. This work was carried out to maximise the recovery of total phenolic content (TPC), total flavonoid content (TFC), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical-scavenging capacity and 2,2′-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging capacity from Morinda citrifolia fruit via modification of the ethanol concentration, extraction time and extraction temperature at minimal processing cost. The optimised conditions yielded values of 881.57 ± 17.74 mg GAE/100 g DW for TPC, 552.53 ± 34.16 mg CE/100 g DW for TFC, 799.20 ± 2.97 µmol TEAC/100 g DW for ABTS and 2,317.01 ± 18.13 µmol TEAC/100 g DW for DPPH were 75% ethanol, 40 min of time and 57 °C. The four responses did not differ significantly (p > 0.05) from predicted values, indicating that models obtained are suitable to the optimisation of extraction conditions for phenolics from M. citrifolia. The relative amounts of flavonoids were 0.784 ± 0.01 mg quercetin/g of extract and 1.021 ± 0.04 mg rutin/g of extract. On the basis of the results obtained, M. citrifolia extract can be used as a valuable bioactive source of natural antioxidants.

Academic burnout and eating disorder among students in Monash University Malaysia

This study examined the prevalence of academic burnout and the relationship between academic burnout and eating disorder among Monash university students for a period of one year. One hundred and thirty-two participants were recruited for the study via advertisement. They were invited to complete three instruments, namely Demographic Questionnaire, Maslach Burnout Inventory - Student Survey (MBI-SS) and Three Factor Eating Questionnaire-Revised 18-item (TFEQ-18). In addition, anthropometric measurements such as weight, height, body mass index (BMI), body fat percentage and waist circumference were taken. All data were collected at baseline and after 6-8weeks. Analysis of Variance (ANOVA), Kruskal-Wallis and Bonferroni pairwise comparison tests were performed using Stata version 13. The prevalence of academic burnout after 6-8weeks was revealed to be 17.4% and 73.5% respectively for moderate and high level of academic burnout respectively. Emotional eating (EEat) scores were significantly different over levels of academic burnout after 6-8weeks (p=0.0103) while no significant differences was observed in other subscales such as cognitive restraint (CR) and uncontrolled eating (UE). These findings evidenced partial associations between academic burnout and eating disorder.

Stability and recovery of cyclodextrin encapsulated catechin in various food matrices

Catechin is astringent in taste, sparingly soluble in water and sensitive to oxygen, light and pH. These properties restrict its application in food products. The present study investigated the stability of inclusion complex (IC) and catechin in various food matrices and investigated in vitro recovery profile of catechin and IC in liquid, semi-solid and solid food matrices. Besides, the sensory profile of IC added yogurt was also determined. Results showed that IC and catechin was more stable in solid matrix compared to semi-solid and liquid matrices. IC added in milk and yogurt show the highest percentage recovery of catechin compared to IC added in cheese and catechin added in all the matrices in in vitro digestive system. Through IC, β-CD masked the bitterness of catechin. These results suggest that protection of antioxidant such as catechin by β-CD inclusion complex may have applications in functional foods and health supplements.

Studies on the storage stability of fermented red dragon fruit ( Hylocereus polyrhizus ) drink

The objective of this work was to study the effect of storage temperatures and duration on the stability of fermented red dragon fruit drink (FRDFD) on its betacyanins content, physicochemical and microbiological qualities (BPM) and determining sensory acceptability. Results showed that both storage temperatures and duration have a significant effect on betacyanins content and physicochemical properties of FRDFD. Aerobic mesophilic and yeast and mold counts were lower than 1u2009×u2009103xa0CFU/mL for FRDFD stored at both temperatures. The loss of betanin (16.53–13.93xa0g/L) at 4xa0°C was 15.73% with no significant changes in physicochemical properties from week two onwards compared to 56.32% (16.53–7.22xa0g/L) of betanin loss at 25xa0°C. At week eight, FRDFD stored at 4xa0°C still contained 13.93xa0g/L betanin with a pH value of 3.46, suggested its potential as a functional drink which is sensory acceptable (mean scoreu2009>u200980% using hedonic test) among consumers.