Talia Hicks

Effect of oxidative treatment on the secondary structure of decoloured bloodmeal

Bloodmeal can be decoloured using peracetic acid resulting in a material with a pale-yellow colour which only needs sodium dodecyl sulphate, water and triethylene glycol to extrude into a semi-transparent bioplastic. Fourier-transform infrared (FTIR) spectroscopy using Synchrotron light was used to investigate the effect of peracetic acid treatment at various concentrations on the spatial distribution of secondary structures within particles of bloodmeal. Oxidation caused aggregation of helical structures into sheets and acetic acid suppressed sheet formation. Decolouring with peracetic acid led to particles with a higher degree of disorder at the outer edges and higher proportions of ordered structures at the core, consistent with the expected diffusion controlled heterogeneous phase decolouring reaction. The degradation of stabilizing intra- and intermolecular interactions and the presence of acetate ions results in increased chain mobility and greater amorphous content in the material, as evidenced by reduction in Tg and greater enthalpy of relaxation with increasing PAA concentration.

Changes to amino acid composition of bloodmeal after chemical oxidation

Bovine-derived bloodmeal can be decoloured using peracetic acid, extruded and injection moulded into a yellow translucent bioplastic. This plastic has different properties to extruded and injection moulded bloodmeal, in that it does not require sodium sulfite or urea to be extrudable. The effect of oxidation on the physical and chemical characteristics of the proteins during bloodmeal decolouring with PAA was studied by assessing changes in the amino acid profile. Polymer interactions, hydrophilicity and the destruction of cysteine crosslinks were measured indirectly by assessing protein solubility, molecular weight distribution and by synchrotron FT-IR analysis. Increasing peracetic acid concentration resulted in an increased loss of iron due to destruction of the porphyrin groups, increased solubility due to destruction or conversion of aromatic amino acids into hydrophilic groups, destruction of lysine, reduced protein content due to increased salt content in the final product, and a larger amount of smaller protein peptides but with a similar average molecular weight to bloodmeal. Amino acid analysis showed an increase in cysteine content in the product, FT-IR of the sulfur groups revealed that these were heavily oxidised, such that some would be unable to participate in disulfide bonds thereby increasing protein solubility.

Protein-Rich By-Products: Production Statistics, Legislative Restrictions, and Management Options

Abstract Congruent to a rapidly growing population is the generation of horticultural and agricultural by-products and waste. The modern-day food cycle includes agricultural production, postharvest handling and storage, food processing and packaging, and distribution and retail, ending with consumption and waste disposal. Of these, agricultural production and postharvest handling and storage result in unintended losses and by-products whereas the other steps generally result in food waste. Approximately one-third of the worldwide food production is wasted each year. Although it is most desirable to prevent waste and by-product formation, followed by reuse or recycling, the formation of by-products and waste is inevitable, and management options must be innovative and also meet legislative requirements. However, management options are mostly a compromise between what is viewed acceptable based on legal requirements and local perceptions, and what is deemed technologically and financially feasible.

Meat Industry Protein By-Products: Sources and Characteristics

Global consumption of meat products established an enormous and constantly growing industry. By-products generated from this industry have a high biological oxygen demand, and if they are not treated properly, then they can have serious implications for the environment. Meat products, such as fish, chicken, beef, sheep, and pork all result in similar waste products. These include carcasses, intestines, feathers, fish bones and scales, as well as blood. Although these can be seen as waste from the meat producer, they become much more valuable after rendering. A variety of products exist, such as gelatin from hooves, meat-and-bone meal from carcasses and intestines as well blood, feather, and fish meal. These are mainly used as animal feed supplements because of their high protein content, but the nutritional properties vary dramatically, and in some cases, further processing is required. In this chapter the sources and properties of animal-based proteins are discussed of their biological composition as well as their physicochemical properties.