1.Fibre from Pumpkin (Cucurbita pepo L.) Seeds and Rinds: Physico-chemical Properties, Antioxidant Capacity and Application as Bakery Product Ingredients
Malaysian Journal of Nutrition 2013;19(1):99-109
Introduction: The aims of this study were to determine the proximate
composition, functional properties and antioxidant activity of pumpkin seeds
and rind. Besides, the effects of dietary fibre in pumpkin seeds and rinds on
bread qualities and properties were evaluated. Methods: Formulations for bread
substituted with 0%, 5% and 10% pumpkin seed and rind, respectively were
produced. Sensory evaluation of the prepared bread samples for such attributes
as appearance, aroma, flavour, texture and overall acceptability was undertaken.
The physical properties of the bread samples, including dough expansion, loaf
volume, crumb colour and bread texture, were determined. Proximate analysis
and determination of antioxidant activity of the bread samples were also
conducted. Results: Crude fibre of the pumpkin seeds and pumpkin rinds was
high at 31.48% and 14.83%, respectively. The total phenolic compound (TPC) and
DPPH radical scavenging activity for the pumpkin rinds were 38.60 mg GAE/
100 g dry weight and 69.38%, respectively, which were higher than those of
pumpkin seeds. A 5% level of pumpkin rind bread gave the best overall
acceptability and sensory attributes, followed by 5% pumpkin seed bread. Total
dietary fibre, total phenolic compound and DPPH radical scavenging activity in
breads substituted with 5% pumpkin seed and 5% pumpkin rind flour were
higher than the values in control bread. Conclusion: Pumpkin seeds and rinds
can be used as dietary fibre sources in bakery.
2.In vitro Antioxidant Activities of Extract and Oil from Roselle (Hibiscus sabdariffa L.) Seed against Sunflower Oil Autoxidation
Nyam KL ; Teh YN ; Tan CP ; Kamariah L
Malaysian Journal of Nutrition 2012;18(2):265-274
Introduction: In order to overcome the stability problems of oils and fats, synthetic antioxidants such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and tert-butyl hydroquinone (TBHQ) have widespread
use as food additives in many countries. Recent reports reveal that these compounds may be implicated in many health risks, including cancer and carcinogenesis. Hence, there is a move towards the use of natural antioxidants of
plant origin to replace these synthetic antioxidants. Methods: In this study, roselle seed oil (RSO) and extract (RSE) were mixed with sunflower oil, respectively to
monitor degradation rate and investigate antioxidant activity during accelerated storage. Results: The antioxidant activity was found to stabilise sunflower oil of various samples and in the order of RSE>RSO>tocopherol>sunflower oil. The total percentage increased after 5 days of storage period in free fatty acid (FFA), peroxide value (PV) and anisidine value (AV). Total oxidation value (TOx) of sunflower oil supplemented with 1500 ppm RSE was 33.3%, 47.7%, 14.5%, and
45.5%, respectively. While the total percentage increased under different analysis methods, sunflower oil supplemented with 5% RSO was 17.2%, 60.4%, 36.2% and
59.0% in the order of FFA, PV, AV and TOTOX. Both RSO and RSE were found to be more effective in stabilisation of sunflower oil compared to tocopherol. Total
phenolic content of RSE was 46.40 ± 1.51 mg GAE/100g of oil while RSO was 12.51 ± 0.15 mg GAE/100g of oil. Conclusion: The data indicates that roselle seed
oil and seed extract are rich in phenolics and antioxidant activities and may be a potential source of natural antioxidants.