Biotechnology Growth Partnership: A Potential Flagship Program in S&T

Nepal Journal of Biotechnology. Jan. 2011, Vol. 1, No. 1 : 55-5

Maillard reaction between pea protein isolate and maltodextrin via wet-heating route for emulsion stabilisation

Pea protein isolate (PPI)-maltodextrin (MD) conjugates were prepared by using controlled Maillard reaction at 90 °C in the solution state (wet-heating route). The degree of conjugation between PPI and MD was measured in terms of evolved colour, UV absorbance, and molecular weight change. Results showed that the degree of Maillard reaction increased with the increase in pH and reaction time; however, the PPI-MD conjugation was optimised and was successfully controlled within the initial stage at pH 7.5 and 8.0 to avoid the formation of melanonids. The random coil content of PPI significantly increased upon conjugation with MD producing more flexible structure. The functional properties of PPI in terms of solubility, surface change (zeta-potential), and emulsifying properties of PPI were significantly improved after conjugation with MD. The highest solubility PPI-MD conjugates was observed at 5 h of reaction. The canola oil-in-water (O/W) emulsion stabilised by PPI-MD 5 h conjugate at 2% of emulsifier concentration and homogenised at 60 MPa for 3 passes had the highest physical stability when subjected to 25–60 °C. These findings indicate that Maillard reaction can be controlled in the initial stage via the wet-heating route and the resulting conjugates can be much effective emulsifiers than plant proteins

Stabilization of ginger essential oil Pickering emulsions by pineapple cellulose nanocrystals

Pickering emulsions (PE) are systems made up of two incompatible fluids, these are stabilized by solid organic or inorganic particles located on their interface. Cellulose nanocrystals (CNCs) are sustainable and biocompatible value-added naturally occurring biomolecules which are being investigated as PE stabilizers in the cosmetic, food, and pharmaceutical industries. The objective of this research was to investigate the efficacy of pineapple cellulose nanocrystals as stabilizers for a ginger essential oil-in-water Pickering emulsion. Anionic pineapple cellulose nanocrystals were prepared by acid hydrolysis. Ginger essential oil-in-water emulsions were prepared by ultrasonication. Pineapple CNC produced stable Pickering emulsions with surface average droplet size of 4.3 μm–6.2 μm, high negative zeta potential, high viscosity, and high adsorption at the interface. Pickering emulsions by ultrasonication were stable against droplet coalescence, phase separation, and droplet flocculation for at least 8 weeks at 25 °C or 40 °C at various droplet sizes. The emulsion droplet size and volume density (droplet size distribution) were evaluated by varying the particle concentration (CNC 0.25 g/100 ml or 0.50 g/100 ml) and/or oil fraction (10–20 g/100 ml). At constant oil fraction, the emulsion viscosity increased as the nanocrystal concentration increased. The cellulose nanocrystal-stabilized ginger oil-Pickering emulsions exhibited shear-thinning characteristics of a pseudo-plastic fluid. Pineapple nanocellulose crystal -stabilized ginger oil-Pickering emulsions exhibited high stability with a creaming index of zero. CNC was found to be an effective Pickering stabilizer for oil-in-water emulsions in various food applications

Diagnostic yield of percutaneous computed tomography guided core needle biopsy of lung lesion and its complications in tertiary hospital

Background: Early diagnosis of lung cancer can reduce its mortality and morbidity. Minimally invasive image guided percutaneous core needle biopsy can obtain tissue sample for diagnosis and staging of lung cancer, which is crucial for correct management of lung lesions. Common complications of lung biopsy include pneumothorax, parenchymal haemorrhage and haemoptysis. The study was aimed to determine diagnostic yield and complications of the percutaneous computed tomography (CT) guided core needle biopsy of lung lesion in tertiary hospital.Methods: Hospital based prospective study was performed in 40 patients in Tribhuvan University Teaching Hospital. CT guided biopsy of lung lesions was performed with 18-gauge semi-automated biopsy instrument. The complications following the biopsy were recorded and correlated with different factors using chi-square test. Histopathology report were obtained to measure the diagnostic yield.Results: Among 40 patients who underwent guided lung biopsy, histopathology showed definitive diagnosis in 37 patients; 31 malignant and 6 benign lesions. Parenchymal haemorrhage, pneumothorax and haemoptysis were seen in 13, 8 and 5 respectively; however, none required active intervention. Emphysema in traversing lung and numbers of pleural punctures used were predictive factors of complication (p value <0.05).Conclusions: The study showed percutaneous image guided core needle biopsy has high diagnostic yield with fewer complication rates and is thus recommended for routine biopsies of lung lesions

Investigating the effectiveness of coacervates produced from conjugated and unconjugated Spirulina protein in delivering unstable oil to the intestinal phase of digestion

This study investigated the potential of complex coacervates produced using Spirulina protein concentrate (SPC) conjugated with maltodextrin (MD) and carrageenan (CG) for encapsulating and delivering sensitive oils. A wet-heating Maillard reaction was employed to conjugate SPC with MD, followed by coacervation with CG to form the conjugate-based coacervates. Additionally, a mixture of unconjugated SPC and MD was coacervated with CG to produce mixture-based coacervates. Both types of coacervates were utilised as wall materials for encapsulating canola oil. The in-vitro digestion of the resulting microcapsules was assessed in oral, gastric, and intestinal phases, focusing on physicochemical parameters such as droplet size, zeta-potential, microstructure, proteolysis, oil release and lipolysis. The findings revealed that microcapsules prepared using both (SPC-MD mixture)-CG and (SPC-MD conjugate)-CG coacervates were remarkably stable against gastric digestion, as evidenced by the minimal production of free amino acids (15 mM). Most of the encapsulated oil (62–67%) was released during the intestinal phase due to the breakdown of the coacervates. Notably, the microcapsules produced with (SPC-MD conjugate)-CG coacervates demonstrated a lower degree of lipolysis (41.77% free fatty acid content) compared to those prepared with (SPC-MD mixture)-CG coacervates (53.35% free fatty acid content). These results highlight the potential of complex coacervates produced using conjugated SPC as promising materials for the encapsulation and delivery of sensitive oils

Measurement of Heat and Pressure Induced Denaturation of Whey Protein Isolate Using Reversed-Phase HPLC and FTIR-Spectroscopy

The protein molecules experience various external stresses leading to denaturation of protein during the process of transforming original whey to the concentrated whey proteins or while the concentrated proteins are used in the protein-enriched food formulation. This study was designed for a comparative assessment of the denaturation of whey protein isolate (WPI) under an important thermal stress, isothermal heat treatment (IHT), and high hydrostatic pressure treatment (HPT). The type and extent of denaturation were determined using reversed-phase HPLC and FTIR spectroscopy. The HPLC results demonstrated that the isothermal heat treatment caused higher denaturation of protein due to IHT at 80oC for 600s (88.38%) than that of HPT (58.5%). However, the infra-red spectroscopic analyses suggested that the HPT caused severe destruction of the structural conformation of WPI. The state of protein has a great impact on food formation; hence, the findings of this study would alert the concentrate protein producers and protein-enriched food manufacturers to prepare more active functional foods. HIGHLIGHTS &nbsp;Heat (IHT) and pressure (HPT) stresses caused 88% and 58% WPI to denature, respectively. &nbsp;Reversed phase-HPLC determined the denatured protein through aggregation. FTIR together with HPLC is required for better characterization of denatured protein

Effects of transglutaminase pre-crosslinking on salt-induced gelation of soy protein isolate emulsion

peer-reviewedThe salt-induced gelation behavior of soy protein isolate (SPI) emulsions was markedly influenced by microbial transglutaminase (TGase) pre-crosslinking. Rheological data showed that when SPI emulsions were incubated with TGase at low concentrations (1 and 3 U/g protein) at 50 °C for 30 min prior to gelation, no change in storage modulus (G′), but enhanced resistance to deformation of the gels was observed. Extensive crosslinking by TGase (5 U/g protein) resulted in severe decreases in gel firmness and fracture properties (yielding stress and strain), likely due to the impairment of hydrophobic bonds and the formation of coarse networks. The water-holding capacity of the gels was significantly enhanced by increased concentrations of TGase. Interactive force analysis indicated that non-covalent interactions and disulfide bonds are the primary forces involved in CaSO4-induced SPI emulsion gel, but TGase treatment may limit hydrophobic interactions within the gel network. These results are of great potential value for the application of TGase in the food industry

Surface modification of spray dried food and emulsion powders with surface-active proteins : A review

Spray drying is a well-established and widely used method for transforming a wide range of liquid food products into powder form. Stickiness is the limitation in spray drying of different sugar and acid-rich food products. To minimize this problem process and material science based approaches are in place. However, these remedies have their own drawbacks. Surface modification of droplets/particles is a novel way to minimize stickiness. It is timely that the research efforts on surface modification of droplets/particles be reviewed. Therefore, this review highlights the recent research dealing with surface modification of emulsions and spray dried powders. The theoretical foundation, mechanisms and methods used to achieve surface modification of food and emulsion powders are highlighted. © 2009 Elsevier Ltd. All rights reserved

Effect of oxides and nitrates of lead on the sintering and densification of hydroxyapatite adsorbents

International audienceThe effect of lead oxide (PbO2) and lead nitrate [Pb(NO3)(2)] on sintering and densification of calcium hydroxyapatite (CaHAP) was studied using surface area reduction and shrinkage. The effect of concentration of these additives was studied using 2% and 10% (w/w) mixtures. The addition of (PbO2) and [Pb(NO3)(2)] accelerated the surface area reduction especially when the sintering was accompanied with densification. These additives lowered the densification temperature of HAP. Much lower final densification was achieved when 10% of these additives were used. The rate of densification of pure HAP had only one peak, whereas the mixture had two or more peaks indicating that the additives bring about multiple speeds in the densification process