Carlos Frederico Marques Guimarães

Validade comercial de sardinhas inteiras e refrigeradas avaliada por análises físico-químicas, bacteriológicas e sensorial

Theshelf life of sardines of Sardinella brasiliensis and Cetengraulis edentulus species kept on ice at +2°Cwas determined by physical-chemical, bacteriological and sensory parameters. In both samples, the levels of Total Volatile Bases (TVB) and Trimethylamine (TMA) reached the limits recommended by law (30mg N 100g-1 for TVB and 4mgN100g-1 for TMA) after 14 and 8 days of storage, respectively. The contents of histamine, putrescine and cadaverine remained at levels below 2.0µg g-1 in both samples during the storage period. The hypoxanthine production ranged from 0.65 to 2.62µmol g-1 in samples of S. brasiliensis and 1.40 to 2.09µmol g-1 in samples of C. edentulus. The initial count of Enterobacteriaceae was 3.81logCFU g-1 and 3.82logCFU g-1 reaching, after 18days of storage, 6.57logCFU g-1 and 6.87logCFU g-1, in samples of S. brasiliensis and C. edentulus, respectively. For heterotrophic bacteria aerobic mesophilic and psychrotrophic count the limit of 7logCFU g-1 recommended by international legislation was reached after12 and 8days of storage in samples of S. brasiliensis and after 12 and 6days of storage in samples of C. edentulus, respectively. The quality index method suggested for samples of S. brasiliensis, a limit of acceptable consumption less than 11 and for samples of C. edentulus a limit of acceptability below 14. As a result of this study, we recommend a shelf life of ten days for the S. brasiliensis and nine days for the C. edentulus.

Effect of gamma radiation on lipids by the TBARS and NMR

The aim of this work was to study the effect of gamma radiation on lipids by TBARS and NMR. The samples of raw whole milk were subjected to gamma radiation from Co60 in doses of 1, 2 and 3 kGy and the production of rancidity was studied through Nuclear Magnetic Resonance (NMR) and Thiobarbituric Acid Test (2-TBARS). The TBARS values increased according to the intensity of the radiation dose applied at the samples, demonstrating correlation between the radiation dose and the production of lipid oxidation. This was confirmed by NMR with the formation of peaks of aldehydes and ketones that were small and similar in the doses of 1 and 2 kGy. In the dose of 3 kGy, the total degradation of milk fat was observed. A correlation between the NMR and 2-TBA was detected.

The chemical quality of frozen Vietnamese Pangasius hypophthalmus fillets.

Abstract The aim of the present study was to evaluate the chemical quality parameters regarding frozen Pangasius hypophthalmus specimens from Vietnam. The proximate composition, pH, ammonia, biogenic amines (BAs), total mercury (Hg), malondialdehyde (MDA), and polyphosphate were determined. The moisture, protein, lipid and ash values were between 83.83–85.59, 12.51–14.52, 1.09–1.65, and 0.76–2.38 g 100 g−1, respectively. Fraud by excessive polyphosphate addition was detected in 30% of the samples whereas Hg above the recommended limit was observed in 50% of the samples. With regard to compounds from the degradation process, low concentrations of individual BAs and pH values were found in this study and ranged from 5.88 to 6.18, except for samples with polyphosphate >1 g 100−1 (pH > 7.00) were observed in the present study. However, ammonia concentration indicated that a degradation process initiated in 80% of the samples (0.12–0.34 NH 3 g−1) and 20% of the samples (1.87–1.94 μg NH 3 g−1) were in an advanced deterioration process. Furthermore, MDA values (1.21–7.88 mg kg−1) suggested some failures, mainly during transportation and/or storage. We concluded that quality control measures must be implemented on the Pangasius production chain to improve the quality of products provided to consumers worldwide.

A new sample collection method for the assessment of the percentage of water absorbed in frozen and quick-frozen poultry cuts (chicken breasts with skin)

The determination of the mean physiological water/protein ratio of samples obtained from homogenized poultry cuts using a powerful mincer is an efficient way of determining their total water content. However, this standard method demands expensive equipment and takes unnecessary time. The proposed new system to obtain samples uses a drill and a metal funnel to perform the collection, and it has the same accuracy, a faster performance and a less costly process. Comparing the traditional method to the method proposed in this current work to calculate the average water and protein content and water/protein ratio measured in 22 samples of breast meat cuts, the results analysis has shown that all of the tests performed on the 22 samples gave very similar data (paired t-test p > 0.05). Therefore, these positive outcomes indicate the high potential of using this new sample collection method to determine the total water content of poultry cuts (chicken breasts with skin).