Prasad S. Variyar

Hydrophobic derivatives of guar gum hydrolyzate and gum Arabic as matrices for microencapsulation of mint oil

Guar gum hydrolyzate (GGH) modified with n-octenyl succinic anhydride (OSA) and oleic acid having induced hydrophobicity was evaluated for encapsulation of mint oil and compared with gum Arabic (GA) and GA-OSA as wall material. Spray dried microcapsules prepared with these wall materials were evaluated for qualitative changes by principal component analysis and for percent retention of mint oil during 8-week storage. Results revealed that microcapsules with GGH-OSA and GGH-oleate showed slightly lower retention of mint oil as compared to GA. GA-OSA microcapsules showed better retention of mint oil than GA itself, as observed from the t1/2, the time required for the mint oil to come down to 50% of its original content. The t1/2 of mint oil in microcapsules of GA, GGH-oleate, GGH-OSA and GA-OSA was 26.12, 23.50, 24.11 and 29.67 weeks, respectively. The results suggested that GGH-OSA has the potential to replace gum Arabic for encapsulation of mint oil.

Immunomodulatory and radioprotective effects of lignans derived from fresh nutmeg mace (Myristica fragrans) in mammalian splenocytes

Recently, the lignans present in the aqueous extract of fresh nutmeg mace (aril of the fruit of Myristica fragrans) were shown to possess antioxidant properties in cell free systems and protected PUC18 plasmid against radiation-induced DNA damage. The present report describes the immunomodulatory and radiomodifying properties of lignans present in the aqueous extract of fresh nutmeg mace in mammalian splenocytes. These macelignans (ML) inhibited the proliferation of splenocytes in response to polyclonal T cell mitogen concanavalin A (Con A). This inhibition of proliferation was due to cell cycle arrest in G1 phase and augmentation of apoptosis as shown by increase in pre G1 cells. The increase in activation induced cell death by ML was dose dependent. It was found to inhibit the transcription of IL-2 and IL-4 genes in response to Con A. The production of IL-2, IL-4 and IFN-gamma cytokines was significantly inhibited by ML in Con A-stimulated lymphocytes in a dose dependent manner. ML protected splenocytes against radiation-induced intracellular ROS production in a dose dependent manner. ML was not cytotoxic towards lymphocytes. On the contrary, it significantly inhibited the radiation-induced DNA damage in splenocytes as indicated by decrease in DNA fragmentation. To our knowledge, this is the first report showing the antioxidant, radioprotective and immunomodulatory effects of lignans in mammalian cells.

Natural existence of 2-alkylcyclobutanones.

Increased outbreaks of food-borne illnesses, including deaths in recent years, attributed in large part to consumption of food contaminated with Escherichia coli O157:H7, have become a worldwide concern. Food-borne illnesses constitute an unacceptable health risk demanding stringent food safety controls. Despite food irradiation being a known effective method to eliminate pathogens that are difficult to eradicate by conventional methods, consumers and industry at large have been reluctant to adopt it. This is mainly attributed to some apprehensions regarding the safety of irradiated food. One such apprehension relates to 2-alkylcylcyclobutanones, unique radiolytic products thought to be formed in minute quantities in food during radiation processing. We demonstrate here for the first time the natural occurrence of 2-dodecylcyclobutanone and 2-tetradecylcyclobutanone in commercial nonirradiated as well as fresh cashew nut samples and 2-decylcyclobutanone as well as 2-dodecylcyclobutanone in nonirradiated nutmeg samples. The presence of 2-tetradecenylcyclobutanone was also observed in both commercial and irradiated cashew nuts. The present study will provide greater impetus for wider adoption of radiation technology for elimination of food-borne pathogenic bacteria without apprehensions about the technology that can help ensure food safety.

Effect of γ-irradiation on the volatile oil constituents of turmeric (Curcuma longa)

Abstract The volatile essential oils from commercial samples of dry turmeric and samples γ-irradiated at a dose of 10 kGy were isolated using simultaneous distillation extraction technique and analyzed by GLC (Gas Liquid Chromatography) and gas chromatography/mass spectrometry (GC/MS). Some of the major compounds identified by GC/MS were α-phellandrene, p-cymene, 1:8cineol, β-caryophyllene, ar-curcumene, zingeberene, s-sesquiphellandrene, nerolidol, turmerone, ar-turmerone, curlone and dehydrozingerone. No detectable differences were observed between the aroma impact compounds of the irradiated and commercial samples.

Hydrocarbons as marker compounds for irradiated cashew nuts

Abstract Volatile long chain hydrocarbons, such as 1-tetradecene, 1-hexadecene and 8-heptadecene, could serve as marker compounds in cashew nuts irradiated at 0.25–1.00 kGy. Monitoring these markers over a storage period of 6 months under ambient conditions showed them to be persistent. The concentrations of the markers increased linearly with radiation dose at all storage periods of the study. However, their concentration decreased marginally with storage at all the dose levels.

Evaluation of Antioxidant Activity and Characterization of Phenolic Constituents of Phyllanthus amarus Root

The antioxidant property of the 70% aqueous ethanol extract of Phyllanthus amarus roots and its ether-soluble, ethyl acetate-soluble, and aqueous fractions were investigated by various in vitro assays. The root extracts showed higher DPPH, hydroxyl, superoxide, and nitric oxide radical scavenging and reducing power activity. Among all the samples, the ethyl acetate-soluble fraction demonstrated highest radical scavenging activity and total phenolics content. Twenty-eight different phenolic compounds were identified by LCMS/MS analysis of the ethyl acetate-soluble fraction. The majority of the compounds were found to exist as their glycosides, and many of these were gallic acid derivatives. Free epicatechin and gallic acid were also identified in the ethyl acetate-soluble fraction. The present investigation suggested that P. amarus root is a potent antioxidant and can be used for the prevention of diseases related to oxidative stress.

Mechanical and barrier properties of guar gum based nano-composite films

Guar gum based nano-composite films were prepared using organically modified (cloisite 20A) and unmodified (nanofil 116) nanoclays. Effect of nanoclay incorporation on mechanical strength, water vapor barrier property, chromatic characteristics and opacity of films was evaluated. Nano-composites were characterized using X-ray scattering, FTIR and scanning electron microscopy. A nanoclay concentration dependent increase in mechanical strength and reduction in water vapor transmission rate was observed. Films containing nanofil 116 (2.5% w/w guar gum) and closite 20A (10% w/w guar gum) demonstrated a 102% and 41% higher tensile strength, respectively, as compared to the control. Lower tensile strength of cloisite 20A films as compared to nanofil 116 films was due to its incompatibility with guar gum. X-ray scattering analysis revealed that interstitial spacing between nanofil 116 and cloisite 20A sheets increased due to intercalation by guar gum polymer. This resulted in improved mechanical and barrier properties of nano-composites compared to control.

Irradiation depolymerized guar gum as partial replacement of gum Arabic for microencapsulation of mint oil

Spray dried microcapsules of mint oil were prepared using gum Arabic alone and its blends with radiation or enzymatically depolymerized guar gum as wall materials. Microcapsules were evaluated for retention of mint oil during 8-week storage during which qualitative changes in encapsulated mint oil was monitored using principal component analysis. The microcapsules with radiation depolymerized guar gum as wall material component could better retain major mint oil compounds such as menthol and isomenthol. The t(1/2) calculated for mint oil in microcapsules of gum Arabic, gum Arabic:radiation depolymerized guar gum (90:10), gum Arabic:enzyme depolymerized guar gum (90:10) was 25.66, 38.50, and 17.11 weeks, respectively. The results suggested a combination of radiation depolymerized guar gum and gum Arabic to show better retention of encapsulated flavour than gum Arabic alone as wall material.

Effect of γ-irradiation on the volatile oil constituents of fresh ginger (zingiber officinale) rhizome

Abstract Volatile essential oils of fresh ginger rhizomes gamma irradiated (60 Gy) for sprout inhibition and non-irradiated control rhizomes were isolated by simultaneous distillation-extraction technique. Major compounds present in these oils were identified by GLC and GC/MS analysis. Zingiberin, β-sesquiphellandrene and ar-curcumene were the major compounds identified with zingiberin accounting for 40% of the essential oil. γ-irradiation at a dose of 60 Gy did not bring about any detectable qualitative and quantitative changes in the aroma constituents of the spice immediately after irradiation.

Stability of lipid constituents in radiation processed fenugreek seeds and turmeric: role of phenolic antioxidants.

Impact of radiation processing on the lipid profile of fenugreek and turmeric was investigated. Oleic and linoleic acid were the dominant fatty acids with an appreciable amount of linolenic acid in both cases. Gamma-irradiation did not bring about any significant changes in the fatty acid profile of these spices despite a high content of unsaturation. The ability of aqueous methanolic extract of both spices with high phenolic content to prevent lipid peroxidation suggests a possible role of phenolic constituents in preventing lipid radiolysis. Among the phenolics identified, kaempferol-3-O-alpha-L-rhamnoside, kaempferol 3,7-O-alpha-L-dirhamnoside, quercetin 3,7-O-alpha-L-dirhamnoside, and 3-O-alpha-L-rhamnosyl quercetin are reported here to occur in fenugreek for the first time. The role of phenolic antioxidants in preventing lipid oxidation in the above spices is discussed.