Mita Lad

Composition and properties of the surface of oil bodies recovered from Echium plantagineum

Neutral-lipids within oilseeds are most commonly stored in oil bodies, small spherical organelles with oleosin proteins inserted through a phospholipid monolayer. Oil bodies extracted from Echium plantagineum are highly enriched in polyunsaturated fatty acids and are stable to coalescence and oxidation. This stability has been attributed to the strong association between the phospholipid monolayer and oleosin proteins. To better understand this association the phospholipid fatty acyl groups of E. Plantagineum oil bodies were determined for the first time; a large proportion (≈70%) of saturated fatty acids were present, and this may aid in oleosin anchorage and thus contributes to oil body stability. The effect of oil body washing on surface charge was also observed (using turbidity, zeta and streaming potentials), and dependent on the washing protocol, E. Plantagineum oil bodies had an isoelectric point of pH 4-5. This is significantly different to pI values for oil bodies from a range of other seeds reported in the literature using isoelectric focusing; a possible explanation for this discrepancy is discussed.

On the origin of sharp peaks in the X-ray diffraction patterns of xanthan powders.

A series of xanthans containing different levels of the charged group pyruvate has been examined. The X-ray diffraction patterns of the powders of these materials had different levels of a sharp pattern superimposed on an amorphous background. As the moisture content increased so the intensity of the sharp pattern increased up to a level between 20% and 40% moisture content where the sharp pattern disappeared. X-ray diffraction pattern identification software and an inorganic X-ray diffraction database showed the origin of the sharp peaks to be due to sodium sulphate polymorphs. The behaviour of the xanthans was thought to be due to the differences in charge on the molecule; however, the increase in the crystalline component observed with increased amounts of water was unexpected. The possibility of the drying of samples was considered but the interplay between ions, the charged polymer and the water present was considered necessary to more closely describe the results.

Enhancing saltiness in emulsion based foods

BackgroundThe concept of enhancing saltiness perception in emulsions and a liquid food formulated with the emulsions (ambient vegetable soup) through increasing salt concentration in the continuous phase while retaining the fat content of the (aqueous continuous) product was evaluated. This was accomplished by increasing the droplet phase volume using duplex emulsion technology. Viscosity and droplet size distribution was measured. Saltiness evaluation was based on simple paired comparison testing (2-Alternate Forced Choice tests, BS ISO 5495:2007).ResultsSingle and duplex emulsions and emulsion-based products had comparable mean oil droplet diameters (25 to 30 μm); however, viscosity of the duplex emulsion systems was considerably higher. Sensory assessment of saltiness of emulsion pairs (2AFC) indicated duplex technology enhanced saltiness perception compared to a single emulsion product at the same salt content (6.3 g/100 g) in both simple emulsions and the formulated food product (P = 0.0596 and 0.0004 respectively) although assessors noted the increased viscosity of the duplex systems. The formulated food product also contained pea starch particles which may have aided product mixing with saliva and thus accelerated tastant transport to the taste buds. Lowering salt content in the duplex systems (to levels of aqueous phase salt concentration similar to the level in the single systems) resulted in duplex systems being perceived as less salty than the single system. It appears that the higher viscosity of the duplex systems could not be “overruled” by enhanced mixing through increased droplet phase volume at lowered salt content.ConclusionsThe results showed that salt reduction may be possible despite the added technology of duplex systems increasing the overall measured viscosity of the product. The changes in viscosity behavior impact mouthfeel, which may be exploitable in addition to the contribution towards salt reduction. With a view to applying this technology to real processed foods, it needs to be tested for the product in question but it should be considered as part of a salt reduction tool box.