Browsing by Author "Navam Hettiarachchy"

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Antioxidant and antibacterial potential of pomegranate peel extracts
(Springer, 2014) Shalini Malviya; Arvind; Alok Jha; Navam Hettiarachchy
Pomegranate peels of Ganesh variety were subjected to extraction using different solvents viz. water, methanol and ethanol either alone or in combination with water. The extraction yield, antioxidant activity (DPPH and ABTS inhibition) and total phenolic contents were evaluated. Highest yield was obtained from 50 % ethanol: 50 % water (16.3 ± 1.99 %). The DPPH and ABTS inhibition activity was found to be the highest for methanol and 70 % ethanol: 30 % water extract (79.5 ± 6.5; 94.6 ± 6.10), respectively. The phenolic content was the highest in the aqueous extract (438.3 ± 14.15). The antibacterial activity of peel extracts was tested against four bacterial strains, Staphylococcus aureus, Enterobacter aerogenes, Salmonella typhi and Klebsiella pneumoniae and the extracts demonstrated remarkable antibacterial activities against all the tested bacterial strains. The 70 % ethanol: 30 % water and 100 % water extract had a higher antioxidant activity and phenolic content and has the potential for nutraceutical application. © 2013, Association of Food Scientists & Technologists (India).
Improved functional properties of glycosylated soy protein isolate using D-glucose and xanthan gum
(Springer India, 2015) Ruiqi Li; Navam Hettiarachchy; Srinivas Rayaprolu; Mike Davis; Satchithanandam Eswaranandam; Alok Jha; Pengyin Chen
Functional properties of the soy protein need to improve to have better applications in food industry. Alkali extracted and acid precipitated soy protein isolate (SPI) was glycosylated using D-glucose (G) and Xanthan gum (X) via Maillard reaction to improve solubility. The effects of SPI to G and SPI to X ratios (SPI:G = 2:1, 1:1, and 1:2; SPI:X = 100:1 and 10:1) and incubation time (0, 6, 12, and 24 h) on the solubility and functional properties of glycosylated SPI were evaluated. The SPI:G ratio of 1:2 yielded a maximum degree of glycosylation of 71.1 %. The solubility of SPI after glycosylation significantly increased (P < 0.05) at pH 4.0–8.0 compared to SPI alone. Although the emulsion stability of glycosylated SPIs has not significantly increased (P > 0.05), the emulsifying activity improved significantly (P < 0.05). Glycosylation with SPI-X at a ratio of 10: 1 showed maximum emulsifying activity of 191.6 m2/g (SPI alone: 66.3 m2/g). Moreover, the SPI:X (ratio of 100:1) showed the maximum foaming activity (205 mL) compared to SPI alone (155 mL). The foaming stability of SPI (2.6 %) increased to 5.5 and 8.2 % when using xanthan gum at the ratio of 100:1 and 10:1, respectively. Glycosylated SPI with enhanced emulsifying and foaming properties has potential to improve the functional quality of the food products. © 2015, Association of Food Scientists & Technologists (India).
Influence of the solvents on the extraction of major phenolic compounds (Punicalagin, ellagic acid and gallic acid) and their antioxidant activities in pomegranate aril
(Springer, 2014) Mithilesh Singh; Alok Jha; Arvind Kumar; Navam Hettiarachchy; Ashiwini K. Rai; Divya Sharma
Phenolic compounds of fruits have been shown to maintain human health. However, the relative amounts of phenolic compounds and the variation in the types of phenolics are still poorly understood. The purpose of this study was to investigate the most effective solvent for extracting the potent antioxidant compounds, especially phenolics from pomegranate aril. Pomegranate aril was subjected to extraction using different solvents viz., water, ethanol, acetone and diethyl ether either alone or in combination, and the extraction yield, total phenolic contents, and antioxidant activity were investigated. The extracts derived from various solvents were also analysed using high performance liquid chromatography (HPLC) for quantification of major polyphenols (punicalagins, ellagic acid and gallic acid) of pomegranate. Amongst the tested solvents, combination of ethanol, diethyl ether and water (8:1:1) extract exhibited the highest 2, 2- diphenyl-1-picrylhydrazyl (DPPH) radical scavenging power (IC50 = 10.12 μg mL-1). Further, HPLC analysis of different extracts revealed that ethanol, diethyl ether and water (8:1:1) mixture contained significantly higher (p<0.05) amounts of punicalagin A (1.06 μg mg-1 extract), punicalagin B (2.07± 0.03 μg mg-1 extract), ellagic acid (34.5 μg mg-1 extract) and gallic acid (3.37 μg mg-1 extract) in comparison to the other solvents used for extraction. The results demonstrate that pomegranate aril is a good source of phenolic compounds with high antioxidant activity and the antioxidant activity is dependent on the type of solvent system that extracts different phenolic compounds with varying polarity. The solvent extracts that showed effective antioxidants activities have the potential for application in suitable food products. © Association of Food Scientists & Technologists (India) 2014.
Phenolics and antioxidant activity of saskatoon berry (amelanchier alnifolia) pomace extract
(Mary Ann Liebert Inc., 2014) Ruiqi Li; Navam Hettiarachchy; Srinivas Rayaprolu; Satchithanandam Eswaranandam; Bruce Howe; Mike Davis; Alok Jha
Saskatoon berries (Amelanchier alnifolia Nutt.) have significantly higher levels of anthocyanins (ACY) among berries with potential health benefits. The pomace is a by-product of juice extracted from berries and is a potential source of inexpensive polyphenols. The objectives of this study were to extract the maximum amount of total phenolics from saskatoon pomace, to determine the antioxidant activity, and to identify individual phenolic components. Pomace extracts showed high content of total phenolics, total ACY, and total flavonoids of 43.3, 2.8, and 10.3 g/kg of dried weight (DW) of pomace. A high oxygen radical absorbing capacity value of 119.4 μmol Trolox equivalents/g DW and free radical scavenging activity of pomace extract (200 ppm, 86.8%) were observed. Five major ACY, two flavonols, and three chlorogenic acids were identified and quantified in pomace extracts. This study shows that saskatoon berries pomace rich in antioxidant phenolics could be extracted by "green" solvents (water and ethanol) and used as suitable food product applications. © 2014, Mary Ann Liebert, Inc.