Application of thermal treatments to enhance gel strength and stability of highly concentrated crayfish-based emulsions

Effect of amaranth and quinoa seed flour on rheological and physicochemical properties of goat meat nuggets

An attempt was made through the present study to prepare gluten free goat meat nuggets by replacing refined wheat flour from product formulation with healthy, dietary fibre rich amaranth (A) and quinoa (Q) flour at different levels. A total of five different treatments viz., AI (1.5% amaranth), AII (3% amaranth), QI (1.5% quinoa) and QII (3% quinoa) were prepared. The physicochemical, colour, texture, sensory and rheological properties of these pseudocereal-added products were evaluated against control (3% refined wheat flour). Emulsion stability of meat batter was significantly affected (P < 0.05) due to addition of amaranth flour (1.5% and 3%) and quinoa (3%). Treatment groups AII and QI had significantly low (P < 0.05) moisture content with respect to control while the amount of fat content showed a reverse trend. Addition of amaranth and quinoa significantly increased (P < 0.05) the dietary fibre in meat products. Rheology of meat batter was affected by types and level of pseudocereal incorporation. Treatment AII had low (P < 0.05) hunter colour lightness value, whereas redness value was low for treatment QI. Effect of added amaranth and quinoa flour was observed on the textural parameters like adhesiveness, cohesiveness, gumminess and chewiness. High scores for almost all the sensory parameters were recorded in pseudocereal-added meat products. Though, all the products were very much acceptable, product with 1.5% quinoa flour was found to have high (P < 0.05) overall acceptability score.

Effect of pH on the thermal gelation of carob protein isolate

The specific aim of this work was to study the capability of a carob protein isolate (CPI) to produce self-supporting gels when subjected to a thermal treatment. CPI aqueous dispersions (10, 20 and 30 wt% protein basis) at three different pH values (2, 6 and 10) were subjected to a heating/cooling process (95 °C-30 min/4 °C-24 h) leading to the formation of self-supporting gels. Those gels were characterized for dynamic rheological properties; water holding capacity (WHC); textural properties; extractability in different media; scanning electron microscopy; and SDS-PAGE profiles of the soluble proteins. The results demonstrated that self-supporting CPI gels can only be obtained at concentrations higher than 20 wt%, being favoured at extreme pH values, especially at alkaline pH. At pH 10, gels with higher dynamic elastic and hardness properties and appropriate WHC were formed due to the promotion of disulphide bonds formation. Thus, if higher rheological properties and hardness are required for thermally treated CPI gels, alkaline pH conditions that favour hydrophobic interactions and disulphide bonding should be selected.

Development of crayfish bio-based plastic materials processed by small-scale injection moulding

BACKGROUND

Protein has been investigated as a source for biodegradable polymeric materials. This work evaluates the development of plastic materials based on crayfish and glycerol blends, processed by injection moulding, as a fully biodegradable alternative to conventional polymer-based plastics. The effect of different additives, namely sodium sulfite or bisulfite as reducing agents, urea as denaturing agent and L-cysteine as cross-linking agent, is also analysed.

RESULTS

The incorporation of any additive always yields an increase in energy efficiency at the mixing stage, but its effect on the mechanical properties of the bioplastics is not so clear, and even dampened. The additive developing a greater effect is L-cysteine, showing higher Young's modulus values and exhibiting a remnant thermosetting potential. Thus, processing at higher temperature yields a remarkable increase in extensibility.

CONCLUSION

This work illustrates the feasibility of crayfish-based green biodegradable plastics, thereby contributing to the search for potential value-added applications for this by-product.