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| Author(s): |
Isabela Rodrigues dos Santos
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Pirassununga. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Zootecnica e Engenharia de Alimentos (FZE/BT) |
| Defense date: | 2016-02-03 |
| Examining board members: |
Marco Antonio Trindade;
Maria Teresa de Alvarenga Freire;
Anna Cecilia Venturini
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| Advisor: | Marco Antonio Trindade |
| Abstract | |
The seek for healthier and minimally processed foods has led industries and researchers to study new forms of food preservation. The objective of this project was 1) to evaluate the effect of modified atmosphere packaging (MAP) in the preservation of lamb loin stored under refrigeration and 2) to evaluate the effect of high pressure on the conservation of marinated beef with reduced sodium content. In both cases, Longissimus lumborum muscles were submitted to microbial count, color evaluation, pH, lipid oxidation (TBARS), cooking losses (CL) and shear force. To study the effect of modified atmosphere packaging, the samples were placed into five MAP systems, 15% O2 + 85% CO2; 30% O2 + 70% CO2; 45% O2 + 55% CO2; 60% O2 + 40% CO2 and vacuum (control) and stored at 1 ° C for 21 days. The color, pH, TBARS, CL and shear force analyzes were performed every seven days and microbiological loads counted twice a week. Different concentrations of oxygen in the headspace brought significant difference in the redness of samples packed in ATM. Until the seventh day of storage the treatments with higher concentration of O2 showed a better color, thereafter vacuum packaging managed to best preserve the myoglobin. Different gas concentrations have not brought significant difference (p> 0.05) in the pH of the meat among treatments. No significant difference among treatments was found for samples packed in ATM for cooking loses and shear force parameters. The modified atmosphere packaging was able to retard the growth of microbial flora on meat. This led to the preservation of the sample for up to 18 days under refrigeration, while samples in vacuum had a shelf life of only 11 days. To evaluate the effect of high pressure in marinated meat, the steaks were inoculated with 106 CFU / g of meat with E. faecium and Listeria innocua and then marinated for 18 hours at 4°C in different solutions: 1% NaCl + 1% citric acid, 1% NaCl + 2% citric acid, 2% NaCl + 2% citric acid and 2% NaCl + 2% citric acid. After marination, samples were subjected to the following pressures: 600MPa, 450MPa, 300MPa and 0MPa (control). The physicochemical and microbiological analyzes were conducted soon after treatment. The high pressure treatment was able to reduce six log cycles of the microbial population when 600MPa was applied to all solutions studied. Without high pressure application, the reduction was only of 1 log cycle in the population of E. faecium when the samples were marinated with 2% NaCl+ 2% acid. The high pressure and different sodium and acid concentrations did not bring difference in the color of the samples. Higher citric acid content in the marinade caused higher (p <0.05) reduction of the pH of the meat, compared with samples of low concentration of acid. In order to slow down lipid oxidation, the experiments demonstrated that both vacuum packaging and citric acid are efficient implementation. The application of 600MPa made the meat significantly tougher than the meat treated with other pressures. The results demonstrated the possibility of extending the shelf-life of the chilled meat by applying different technologies: modified atmosphere packaging for fresh meat and marination of meat with reduced salt content by high pressure use. (AU) | |
| FAPESP's process: | 13/07015-3 - Optimization of modified atmosphere packaging system for extending shelf-life of sheep meat under refrigeration |
| Grantee: | Isabela Rodrigues dos Santos |
| Support Opportunities: | Scholarships in Brazil - Master |