Effect of gamma irradiation on physico-mechanical and structural properties of active Farsi gum-CMC films containing Ziziphora clinopodioides essential oil and lignocellulose nanofibers for meat packaging.

The objective of this study was to examine the effect of gamma irradiation (0, 2.5, and 5 kGy) on physico-mechanical and structural characteristics of films based on Farsi gum-carboxymethyl cellulose supplemented with Ziziphora clinopodioides essential oil (ZEO; 0%, 1%, and 2%) and lignocellulose nanofibers (LCNF; 0%, 1%, and 2%), and their application on fresh minced beef meat's shelf-life during refrigerated temperature (4 ± 1 °C) for 16 days. Gamma irradiation under the 60 Co source at 2.5 and 5 kGy doses did not have a significant effect on thickness, tensile strength, swelling index, oxygen permeability, and water vapor transmission rate of prepared films (P > 0.05). The best microbiological (total viable count, psychrotrophic bacterial count, Pseudomonas spp., Brochothrix thermosphacta, lactic acid bacteria, and Enterobacteriaceae) and chemical (thiobarbituric acid reactive substances, total volatile base nitrogen content, and peroxide value) properties were recorded for samples packaged with ZEO 2% + LCNF 2%, followed by ZEO 2% + LCNF 1%, ZEO 1% + LCNF 2%, and ZEO 1% + LCNF 1%. These results indicate acceptable extensions of hurdle technology for prolonged refrigeration of minced beef meat. PRACTICAL APPLICATION: The application of active packaging films has received considerable interest in extending the shelf-life of perishable foods during prolonged chilled storage. The effects of active Farsi gum-carboxymethyl cellulose films supplemented with Ziziphora clinopodioides essential oil 2% + lignocellulose nanofibers 2% resulted in delaying lipid oxidation and microbial spoilage growth of refrigerated minced beef meat and consequently extending the shelf-life during storage for at least 16 days.

Effect of gamma irradiation on the physicochemical and structural properties of plant seed gums.

The objective of the study was to evaluate the effect of irradiation (0-5 kGy) on the physicochemical properties of two seed gums (guar and locust bean gum). The Hunter color parameters changed upon irradiation, namely "L" value decreased, whereas "a" and "b" values, i.e. redness and yellowness, increased. Irradiation reduced the final viscosity of gums at neutral and acidic pH. Increase in irradiation dose (0-5 kGy) increased the water absorption in the range of 11.75-14.61g/g and 20.04-23.99g/g in guar gum and locust bean gum, respectively. Rheological study of the gums revealed their gel behaviour with higher values of G' than G". G' in native guar gum was observed to increase in the range of 880.39-1332.29Pa while G" increased in the range of 194.21-239.77Pa as the test frequency was raised from 14.6-100s-1. In native locust bean gum, the G' and G" varied in the range of 476.50-1230.50Pa and 300.65-380.30Pa, respectively, under the applied frequency sweep. FT-IR revealed the presence of CH, COOH and CO groups in the guar as well as locust bean gum, in addition to the uronic acid and pyranose rings. The absorption of the functional groups declined upon irradiation.

Radiation dose dependent change in physiochemical, mechanical and barrier properties of guar gum based films.

Mechanical and water vapor barrier properties of biodegradable films prepared from radiation processed guar gum were investigated. Films prepared from GG irradiated up to 500 Gy demonstrated significantly higher tensile strength as compared to non-irradiated control films. This improvement in tensile strength observed was demonstrated to be due to the ordering of polymer structures as confirmed by small angle X-ray scattering analysis. Exposure to doses higher than 500 Gy, however, resulted in a dose dependent decrease in tensile strength. A dose dependent decrease in puncture strength with no significant differences in the percent elongation was also observed at all the doses studied. Water vapor barrier properties of films improved up to 15% due to radiation processing. Radiation processing at lower doses for improving mechanical and barrier properties of guar based packaging films is demonstrated here for the first time.

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.

Microwave assisted synthesis of polyacrylamide grafted gum ghatti and its application as flocculant.

Polyacrylamide chains (PAM) were grafted onto the backbone of gum ghatti by microwave assisted method. The grafting of the PAM chains on the polysaccharide backbone was confirmed through intrinsic viscosity study, FTIR spectroscopy, elemental analysis (C, H & N) and SEM morphology study. The intrinsic viscosity of gum ghatti appreciably improved on grafting of PAM chains, thus resulting grafted product with potential application as superior viscosifier. Further, flocculation efficacy of the graft copolymer was studied initially in kaolin suspension and then in municipal wastewater through 'Jar test' procedure, toward possible application as flocculant for wastewater treatment.

Hydrolytic fragmentation of seed gums under microwave irradiation.

The seed gum solutions of Ipomoea purga, Ipomoea palmata, Ipomoea dasysperma, Cyanaposis tetragonolobus (Guar gum) and Crotolaria medicaginea were microwave (MW) irradiated and their degradation to oligo and monosaccharides was investigated. The gum solutions were fragmented into oligosaccharides/constituent monosaccharides depending upon the length of MW exposure in presence of catalytic amount of mineral acid or even when no acid was used. A mechanism for the microwave induced hydrolytic degradation of the seed gums has been proposed. The MW exposure time required for the partial and complete degradation of the gums was found dependent on the types of the linkages and degree of the branching present in the gums.