Carlos Adam Conte Junior

Simultaneous analysis of carbohydrates and organic acids by HPLC-DAD-RI for monitoring goat's milk yogurts fermentation

During yogurt manufacture, the lactose fermentation and organic acid production can be used to monitor the fermentation process by starter cultures and probiotic bacteria. In the present work, a simple, sensitive and reproducible high-performance liquid chromatography with dual detectors, diode array detector and refractive index was validated by simultaneous analysis of carbohydrates and organic acids in goat milk yogurts. In addition, pH and bacterial analysis were performed. Separation of all the compounds was performed on an Aminex HPX-87H column (300×7.8 mm, 9 µm) utilizing a 3 mmol L(-1) sulfuric acid aqueous mobile phase under isocratic conditions. Lactose, glucose, galactose, citric, lactic and formic acids were used to evaluate the following performance parameters: selectivity, linearity, precision, limit of detection (LOD), limit of quantification (LOQ), decision limits (CCα), detection capabilities (CCβ), recovery and robustness. For the method application a six goat milk yogurts were elaborated: natural, probiotic, prebiotic, symbiotic, cupuassu fruit pulp, and probiotic with cupuassu fruit pulp. The validated method presented an excellent selectivity with no significant matrix effect, and a broad linear study range with coefficients of determination higher than 0.995. The relative standard deviation was lower than 10% under repeatability and within-laboratory reproducibility conditions for the studied analytes. The LOD of the method was defined from 0.001 to 0.003 µg g(-1), and the LOQ from 0.003 to 0.013 µg g(-1). The CCα was ranged from 0.032 to 0.943 µg g(-1), and the CCβ from 0.053 to 1.604 µg g(-1). The obtained recovery values were from 78% to 119%. In addition, the method exhibited an appropriate robustness for all parameter evaluated. Base in our data, it was concluded that the performance parameters demonstrated total method adequacy for the detection and quantification of carbohydrates and organic acids in goat milk yogurts. The application of the method was successfully applied to monitoring different goat milk yogurts during fermentation.

Determination of biogenic amines by high-performance liquid chromatography (HPLC-DAD) in probiotic cow's and goat's fermented milks and acceptance

This study evaluated the presence of biogenic amines in fermented cows and goats milks containing probiotic bacteria, during the first 10 days of chilled storage (4 ± 2°C), when the probiotic strains are most viable. The overall acceptance of both fermented milks, produced using the same starter culture and probiotics, was tested. In both products, the initially high levels of tyramine (560 mg kg−1 means for both fermented milks), the predominant biogenic amine, increased during the storage period, which may be considered this amine as a quality index for fermented milks. The other principal biogenic amines (putrescine, cadaverine, histamine, and spermidine) were produced on days 1–5 of storage, and thereafter decreased. At the end of the 10th day, these amines, respectively, showed values of fermented cows milk 20.26, 29.09, 17.97, and 82.07 mg kg−1; and values of fermented goats milk 22.92, 29.09, 34.85, and 53.85 mg kg−1, in fermented cows and goats milk. Fermented cows milk was well accepted compared to fermented goats milk. The results suggested that the content of biogenic amines may be a criterion for selecting lactic acid bacteria used to produce fermented milks.

Development and nutritional and sensory evaluation of cachapinta (Pseudoplatystoma sp) pâté

This study developed a technique for the preparation of pâté from cachapinta (Pseudoplatystoma sp) waste. For this, frozen minced cachapinta fish was crushed in a mini cutter and homogenized with all other ingredients. The prepared pâté was stored in seamed and thermally treated cans (volume 170 g). Weight proportions of mean moisture, ash, protein, and lipid contents of the minced fish were 75.49, 1.00, 15.00, and 7.92 (g/100 g), respectively. The formulation of the developed pâté is in accordance with legislation for fish products. Cachapinta pâté is a product with high content of polyunsaturated fatty acids, low level of trans fat, and good indices of nutritional quality. Tests of sensory acceptance, purchase intent, and sensory attributes (except spreadability) averaged a score above 6.0, indicating acceptability of the product. Our study suggests that the potential of minced cachapinta for pâté production is high, and that it can contribute a value-added product to seafood consumption.

INFLUENCE OF THE TIME/TEMPERATURE BINOMIAL ON THE HYDROXYMETHYLFURFURAL CONTENT OF FLORAL HONEYS SUBJECTED TO HEAT TREATMENT Influência do binômio tempo e temperatura nos teores de hidroximetilfurfural em méis florais submetidos ao aquecimento

Hydroxymethylfurfural (HMF) content is internationally recognized for its ability to indicate the freshness or lack of freshness of honey and can be used to judge the processing and storage condition of honey. The objective of the present study was to evaluate the evolution of HMF levels in fresh extracted honeys submitted to different temperatures ranging from 30 to 100o C, during pre-established time intervals (30, 45, 60, 180 and 720 minutes).The test was conducted in floral honey with an initial HMF content of 2.2 mg/Kg. The maximum value recommended by the Brazilian law (60 mg/Kg) was not exceeded in the samples subjected to heating for 30, 45 and 60 minutes regardless of the temperatures used. When the samples were heat treated during 180 minutes at 90o C the official value was surpassed. The highest values were observed in samples subjected to heating over 720 minutes, and the limit was exceeded at 70o C. The results obtained indicate that the HMF content gradually increases when the honey is heated at high temperatures for long periods. Therefore, we suggest a process optimization, considering the initial HMF content of the product and standardizing times and temperatures to ensure a good quality of the final product.

Influência do ácido lático e da embalagem em atmosfera modificada sobre a validade comercial da linguiça frescal de frango

The present work has an objective to observe and to characterize, through microbiological analyses and pH determination, the influence of the Modified Atmosphere Packaging (MAP) and the lactic acid addictive in shelf life of fresh poultry sausage. Two sausage batches were made under laboratory control. One of them was added of lactic acid (0.15%). The samples were processed, and packaged in plastic bags (four sausages per bag). Finally, the bags were filled with different atmospheres: 100% air, 100% N2, 100% CO2, 80/20 CO2/N2, 40/60 CO2/N2 and 20/80 CO2/N2. Samples were stored in walk?in cold rooms at 4±2°C. Samples were taken at different days of storage (zero, 1, 9 and 16). Both added and not added with lactic acid samples were subjected to total viable aerobic counts (mesophylic and psycrophylic), lactic acid bacteria, Enterobacteriaceae, and Pseudomonas sp. in specific media plates. Also, it was determinate the pH of all the samples. The results were arranged in tables and graphs for the descriptive statistical analyses. The MAP 80/20 CO2/N2 was the more effective method to conserve fresh poultry sausages, reaching at the end of the experiment values of 6.0; 5,3 and 5.0 Log UFC/g (mesophylic, psycrophylic and acid-lactic bacteria, respectively), comparing to the conventional package (100% air) and 100% N2 that reached at the end of the experiment maximum values of 8.8 and 9.4 Log UFC/g, respectively. The addition of the acid lactic was effective about the aspect of microbiological inhibition, reaching inferior values in almost all the atmospheres comparing to the samples without addition of the acid, except to 80/20 CO2/N2, that the values of the microbial count in both treatments (with and without acid) they were very close. During the experiment, it was not observed the growth of Enterobacteriaceae and Pseudomonas. Analyzing the pH, it can be observed that the addition of 0.15% lactic acid caused a fall of the pH of 5.89 for ~5.50, enough to inhibit the microbial multiplication in the different atmospheres, except in 80/20 CO2/N2. After analyzed this results, it was concluded that MAP to 80/20% of CO2/N2 was the more effective method to increase the shelf life of the fresh poultry sausage, added or not added with lactic acid; the addition of 0.15% of lactic acid was an effective alternative for conservation of fresh poultry sausage chicken, wrapped or not in modified atmosphere.

Detecção cromatográfica de nitrofuranos em alimentos de origem animal

Nitrofurans are antibacterials banned in livestock by different countries due to its relationship with the production of carcinogenic metabolites. Several studies have been conducted to find the best methodology to identify these residues. Te objectives of this review work were to show the risk of nitrofuran metabolites (furazolidone; nitrofurazone; nitrofurantoin, furaltadone and nifursol); to explain the application of liquid chromatography and mass spectrometry to determine the presence of these residues in foods of animal origin; and, finally, to report some methodologies that were recently used in different foods of animal origin.

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.

Contaminação por metais traço em mexilhões Perna perna da costa brasileira

Trace elements are considered toxic in high levels for human and animal organisms. In aquatic environment, some elements can form organic compounds and tend to bioaccumulate in organisms tissues. Bivalve mollusks participate on the metallic contaminants dynamics in aquatic environment due to capacity in concentrate trace elements in their soft tissues in higher levels than in water. Mussels are mollusks widely used as bioindicators of trace metal pollution in coastal areas because they can accumulate various elements as filter-feeders. In Brazil, Perna perna is one of the most commonly consumed bivalve mollusks and the most cultivated in coast regions. Therefore, the consumption of mussels may be a potential risk for human health, which enhances the importance to know trace metal levels in environment that provides food to humans. Due to constantly search for environmental quality and the use of mussels as food and often employed to monitor metal pollution in sea, it is of great interest and importance an overview of metallic contamination in national territory to assist in prevention of intoxication by trace elements.

Effect of the UV-C Radiation on Shelf Life of Vacuum-Packed Refrigerated Pirarucu (Arapaima gigas) Fillets

ABSTRACT The effect of Ultraviolet radiation type C (UV-C) radiation (0.100 ± 0.010 J/cm2) on shelf life of Arapaima gigas fillets stored at 4 ± 1°C for 18 days was investigated. The samples were analyzed for total aerobic mesophilic bacteria (TAMB) counts; total aerobic psychrotrophic bacteria (TAPB) counts; Enterobacteriaceae; purge loss; pH; lipid oxidation; total volatile bases (TVB-N); ammonia; biogenic amines (BAs); and L*, a*, and b* values. UV-C radiation increased (P < 0.05) the generation time of all bacterial groups evaluated, increasing the shelf life by 2 days. UV-C-treated fillets showed lower (P < 0.05) L* values, purge loss, pH, TVB-N, ammonia, and BAs levels than their control counterparts throughout the storage period. Moreover, UV-C treatment did not result (P > 0.05) in detrimental effects on lipid oxidation or a* and b* values. UV-C at 0.100 J/cm2 demonstrated a good potential for use in A. gigas fillets and, therefore, it could be applied at industrial scale.

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).