Abstract
In meat production, blood is an unavoidable by-product often discarded by abattoirs as waste. The available methods for blood disposal either have negative environmental impacts or are associated with high costs. To mitigate these challenges, blood can be hygienically collected and utilised to produce food products. This approach presents opportunities for nutritional, economic, and environmental benefits. This study aimed to produce blood sausages using pig blood as a by-product of pork production. The pig blood sausages were produced using four different formulations. The formulations consisted of pig blood, pig skin and fat as the main ingredients and were varied with cereal and low-value meat as filler ingredients; Sausage A (no meat or cereal fillers), Sausage B (20 % meat fillers), Sausage C (15 % meat and 5 % cereal fillers), and Sausage D (10 % meat and 10 % cereal fillers). Thereafter, the cooking loss, proximate composition, nutritional, sensory, and textural characteristics of pig blood sausages were determined. Furthermore, the shelf-life stability was evaluated by monitoring changes in aw, pH and microbiological quality (total viable count (TVC), Enterobacteriaceae, yeasts and moulds, lactic acid bacteria (LAB), Staphylococcus aureus, Pseudomonas spp., Salmonella spp. and Listeria monocytogenes) at 4°C for up to 14 days for polyvinyl chloride (PVC) packaging and 21 days for vacuum packaged (VP) pig blood sausages. Lastly, lipid oxidation at -10°C for up to 60 days in PVC packaging was determined.
The results showed a significant reduction in cooking loss and increased moisture content when the fillers were added. The fillers reduced the protein, fat and ash content of the blood sausages, while the addition of cereals increased the carbohydrate content. The fillers negatively affected the composition of certain minerals composition (Ca, Mg, Mn, Cu). The main fatty acids present in the blood sausages were oleic (C18:1), linolenic (C18:2), stearic (C18:0) and palmitic (C16:0). All blood sausages contain essential amino acids, and the Digestible indispensable amino acid score (DIAAS) calculation indicates that sausages can be either good or excellent sources of proteins. The texture profile analysis (TPA) showed that meat fillers increased the hardness and chewiness, whereas the cereals significantly reduced these parameters. The cohesiveness of the sausages was not affected by any of the fillers. The
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quantitative descriptive analysis suggests that Sausage B and C could be preferred by the consumers because Sausages B and C were characterised by aromas and flavours related to meat products.
The sausages remained stable in terms of aw, while pH levels decreased during storage. No foodborne pathogens (L. monocytogenes, Salmonella, S. aureus) were detected during the storage period. Pseudomonas spp., TVC, and LAB counts increased during storage. Enterobacteriaceae counts stayed consistent, and yeasts and moulds count increased for 14 days before decreasing in vacuum packaging on day 21. The lipid oxidation results showed that during the 60-day storage period at -10°C, the TBARS levels in PVC packaged sausages increased. Sausages formulated with cereal fillers (Sausages C and D) exceeded the recommended TBARS levels on the last day of storage. Based on the results of the microbiological evaluation, it is recommended to have a 7-day shelf life for PVC-packaged blood sausages and a 21-day shelf life for VP blood sausages. Overall, results showed that meat and cereal fillers can be added to the formulation of blood sausages. However, they must be carefully selected because the type of filler ingredient influences the quality of pig blood sausages.