• Effects of cold atmospheric plasma on mackerel lipid and protein oxidation during storage

      Pérez-Andrés, Juan M.; de Alba, María; Harrison, Sabine M.; Brunton, Nigel; Cullen, P. J.; Tiwari, Brijesh K; European Union; Joint Programming Initiative; 692276; 15/HDHL/1 PROHEALTH (Elsevier BV, 2019-09-27)
      The present study investigated the effects of cold atmospheric plasma on the shelf-life stability of lipids and proteins of commercially packaged mackerel fillets. The results showed no significant effects on lipid oxidation between the control samples and those treated at 80 kV for extended treatment times of 5 min using an in-package plasma system. In addition, no significant changes (p > 0.05) were found in the fatty acid composition or nutritional quality indices after treatment. Finally, the formation of carbonyls was accelerated by plasma treatment at the end of the storage period for 4 °C and 8 °C. These results suggest that cold atmospheric plasma technologies are potentially suitable as processing technologies for the fish industry.
    • Integrated phenotypic-genotypic approach to understand the influence of ultrasound on metabolic response of Lactobacillus sakei

      Ojha, K. Shikha; Burgess, Catherine; Duffy, Geraldine; Kerry, Joseph P.; Tiwari, Brijesh K; Teagasc Walsh Fellowship Programme (PLOS, 2018-01-25)
      The lethal effects of soundwaves on a range of microorganisms have been known for almost a century whereas, the use of ultrasound to promote or control their activity is much more recent. Moreover, the fundamental molecular mechanism influencing the behaviour of microorganisms subjected to ultrasonic waves is not well established. In this study, we investigated the influence of ultrasonic frequencies of 20, 45, 130 and 950 kHz on growth kinetics of Lactobacillus sakei. A significant increase in the growth rate of L. sakei was observed following ultrasound treatment at 20 kHz despite the treatment yielding a significant reduction of ca. 3 log cfu/mL in cells count. Scanning electron microscopy showed that ultrasound caused significant changes on the cell surface of L. sakei culture with the formation of pores “sonoporation”. Phenotypic microarrays showed that all ultrasound treated L. sakei after exposure to various carbon, nitrogen, phosphorus and sulphur sources had significant variations in nutrient utilisation. Integration of this phenotypic data with the genome of L. sakei revealed that various metabolic pathways were being influenced by the ultrasound treatments. Results presented in this study showed that the physiological response of L. sakei in response to US is frequency dependent and that it can influence metabolic pathways. Hence, ultrasound treatments can be employed to modulate microbial activity for specialised applications.
    • Survival characteristics of monophasic Salmonella Typhimurium 4,[5],12:i:- strains derived from pig feed ingredients and compound feed

      Burns, Ann Marie; Duffy, Geraldine; Walsh, Des; Tiwari, Brijesh K; Grant, Jim; Lawlor, Peadar G; Gardiner, Gillian E.; Teagasc Walsh Fellowship Programme; 2011010 (Elsevier, 2015-12-09)
      The presence of Salmonella in animal feed or feed ingredients at the feed mill or on-farm is a cause for concern, as it can be transmitted to food-producing animals and subsequently to humans. The objective of this study was to determine the survival characteristics of five feed ingredient- and feed-derived monophasic Salmonella Typhimurium 4,[5],12:i:- strains. The first part of the study investigated thermal inactivation using an immersed heating coil apparatus. A Weibull model provided a good fit, with low RMSE values (0.04–0.43) and high R2 values (0.93–0.99) obtained. There was considerable inter-strain variation in heat resistance, with D-values ranging from 397.83 to 689 s at 55 °C, 11.35–260.95 s at 60 °C and 1.12 to 6.81 at 65 °C. Likewise, z-values ranged from 2.95 to 5.44 °C. One strain demonstrated a significantly higher thermal tolerance, even though it had been isolated from a meal feed. However, overall the strains investigated do not appear to be that much more heat resistant than Salmonella previously studied. The second part of this study involved assessing the ability of the five Salmonella strains to survive during storage over a 28-day period in pelleted weaner pig feed treated with 0.3% sodium butyrate. While a mean reduction in the Salmonella count of 0.79 log10 CFU was seen in the treated feed during the storage period, a reduction (albeit only 0.49 log10 CFU) was also observed in the control feed. Although there was no overall effect of treatment, sodium butyrate resulted in reductions in Salmonella counts of 0.75 and 0.22 log10 CFU at days 14 and 24 of feed storage, respectively but at the end of the 28-day storage period counts were 0.25 log10 CFU higher in the treated feed. Therefore, the sodium butyrate used appears unsuitable as an agent for feed treatment perhaps due to the protective coating on the particular feed additive used. Overall, the results of this study enhance knowledge about the behaviour and survival characteristics of monophasic S. Typhimurium 4,[5],12:i:- strains in animal feed and may assist the feed industry and pig producers in implementing effective intervention strategies for their control.
    • Ultrasound-assisted extraction of polyphenols from potato peels: profiling and kinetic modelling

      Kumari, Bibha; Tiwari, Brijesh K; Hossain, Mohammad Billal; Rai, Dilip K.; Brunton, Nigel; Department of Agriculture, Food and Marine; FIRM/11/F/050 (Wiley, 2017-02-14)
      Ultrasound‐assisted extraction (UAE) at 33 and 42 kHz has been investigated in the extraction of polyphenols from peels of two potato varieties, cream‐skinned Lady Claire (LC) and pink‐skinned Lady Rosetta (LR), commonly used in snack food production. Extraction efficacy between the UAE‐untreated (control) and the UAE‐treated extracts was assessed on the total phenolic content and antioxidant capacities (DPPH and FRAP). Application of UAE showed significantly higher recovery of phenolic compounds compared to solid–liquid extraction process alone. Lower ultrasonic frequency (33 kHz) was more effective in recovering polyphenols compared to 42 kHz ultrasonic treatment. The liquid chromatography‐tandem mass spectrometry revealed that chlorogenic acid and caffeic acid were the most prevalent phenolics in LR peels, whereas caffeic acid was dominant in LC peels. Peleg's equation showed a good correlation (R2 > 0.92) between the experimental values and the predicted values on the kinetics of UAE of phenolic compounds.
    • Ultrasound-Assisted Marination: Role of Frequencies and Treatment Time on the Quality of Sodium-Reduced Poultry Meat

      Inguglia, Elena Sofia; Burgess, Catherine; Kerry, Joseph P.; Tiwari, Brijesh K; Teagasc Walsh Fellowship Programme (MDPI AG, 2019-10-11)
      The objective of this study was to evaluate the influence of high-power ultrasound (US) to accelerate marination of chicken breast; the effect of ultrasonic frequencies and marination times were investigated on samples containing full sodium levels (FS) or 25% sodium reduction, either by reducing NaCl (R50) or by its partial substitution with KCl (SR). Chicken breasts were marinated in plastic bags immersed in an ultrasonic bath operating with a frequency of 25, 45 or 130 kHz for 1, 3 or 6 h at a temperature of 2.5 ± 0.5 ◦C. Chicken marinated using US had a significantly higher uptake (p < 0.05) of sodium compared to control samples (no US) marinated for the same amount of time. No significant changes were observed in the quality parameters of sonicated chicken samples compared to controls. However, significant decreases (p < 0.05) in lipid oxidation were observed in SR samples when treated by US. These results suggest the use of ultrasound in the meat processing industry as a novel technology for enhancing marination processes and formulation of reduced sodium meat products.