Restriction lift date: 2027-07-24
Application of novel processing technologies for salt reduction in meat products
Inguglia, Elena S.
University College Cork
Currently, daily sodium intake is approximately three-times the recommended daily allowance for an adult. Processed meat products are generally high in salt and 20% of the total sodium dietary intake is linked to this category. This thesis assesses the feasibility of employing novel processing technologies to develop reduced-salt meat products. To achieve these objectives, a series of six studies were carried out, proposing three different strategies: i) enhancement of salt diffusion by power ultrasound (US), ii) improvement of natural saltiness by high pressure processing (HPP) and iii) use of plasma technology as an alternative curing source. The first four chapters are focus on the use of US alone or in combination with salt blends (NaCl/KCl), to enhance salt diffusion and distribution. Initially, in Chapter 2 the operation parameters of the US system influencing salt uptake are investigated; modifications in moisture and salt content were used to evaluate salt distribution in the samples. Results of this chapter identify US has a faster processing tool and suggest that geometric parameters of US systems can have a strong influence on the efficiency of US-assisted brining. Subsequently, to address possible concerns related to salt reduction and safety of the product, the efficacy of power US for the inactivation of Escherichia coli and Listeria innocua was investigated, first in broth (Chapter 3), and then on reduced salt meat (Chapter 4). Inactivation curves of inoculated bacterial suspensions were fitted to the Weibull and Biphasic models. In meat, total viable counts, lactic acid and inoculated bacteria were monitored during storage at 4 and 10oC, along with quality parameters. US-brining achieved 25% sodium reduction, with a processing time almost four-times shorter than standard curing, with minor impact on key meat quality parameters. Whilst no differences were observed in the growth parameters of inoculated bacteria on the meat surfaces, inactivation of bacteria in broth subjected to US treatment suggest the potential of US as a hurdle-technology to prevent cross-contamination during processing and to minimize processing losses by extending the shelf life of the brines. Additionally, the role of US-processing to achieve salt reduction was further investigated in Chapter 5, where US bath operating at a frequency of 25, 45 or 130 kHz was used to assist the marination of chicken samples. Significant decreases in lipid oxidation values was observed in salt-reduced samples treated with US. However, US processing alone, without the functional support of other salts, could not compensate for texture loss caused by further salt reduction. In Chapter 6, another technological strategy to increase product saltiness was asses by using micro salt (<30 µm), incorporated into Lyoner sausages at 1.5% and 1.0% levels and compared to standard salt at 2.0% salt. Reduced salt samples passed unrecognized by the sensory panels, suggesting advantages in the use of micronized salt over regular salt to intensify saltiness. Furthermore, additional processing with HPP (200 MPa), led to sensorial acceptance of sample with 1% micro salt, suggesting that further development of this method could allow for up to 50% salt reduction in emulsified meat products. Finally, in Chapter 7, the use of plasma-activated brine (PAB) as a novel alternative source of nitrite for meat curing was proposed. Both, air and nitrogen (N2) gas were used to generate plasma; results showed that when air plasma was used, higher levels of nitrites were formed in PAB, with no significant differences in the texture and lipid oxidation of the beef jerky produced. Overall, the research conducted in this thesis contributed to increase the range of technologies and applications in the area of non-thermal processing. Further optimization of these processes could find successful uses for the development of healthier processed meat products.
Salt reduction , Meat , Novel technologies , Meat processing
Inguglia, E. S. 2019. Application of novel processing technologies for salt reduction in meat products. PhD Thesis, University College Cork.