C.A. Conte Júnior

Preference mapping of dulce de leche commercialized in Brazilian markets

Dulce de leche samples available in the Brazilian market were submitted to sensory profiling by quantitative descriptive analysis and acceptance test, as well sensory evaluation using the just-about-right scale and purchase intent. External preference mapping and the ideal sensory characteristics of dulce de leche were determined. The results were also evaluated by principal component analysis, hierarchical cluster analysis, partial least squares regression, artificial neural networks, and logistic regression. Overall, significant product acceptance was related to intermediate scores of the sensory attributes in the descriptive test, and this trend was observed even after consumer segmentation. The results obtained by sensometric techniques showed that optimizing an ideal dulce de leche from the sensory standpoint is a multidimensional process, with necessary adjustments on the appearance, aroma, taste, and texture attributes of the product for better consumer acceptance and purchase. The optimum dulce de leche was characterized by high scores for the attributes sweet taste, caramel taste, brightness, color, and caramel aroma in accordance with the preference mapping findings. In industrial terms, this means changing the parameters used in the thermal treatment and quantitative changes in the ingredients used in formulations.

Physico-chemical changes during storage and sensory acceptance of low sodium probiotic Minas cheese added with arginine

The partial substitution of sodium chloride by potassium chloride (0%, 25%, and 50%) and addition of arginine (1% w/w) in probiotic Minas cheese was investigated. Microbiological (Lactococcus lactis and Lactobacillus acidophilus counts, and functionality of the prebiotics L. acidophilus), physicochemical (pH, proteolysis, organic acids, fatty acids, and volatile profiles), rheological (uniaxial compression) and sensory (hedonic test with 100 consumers) characterizations were carried out. The sodium reduction and addition of arginine did not constitute a hurdle to lactic and probiotic bacteria survival, with presented values of about 9 log CFU/g, ranging from 7.11 to 9.21 log CFU/g, respectively. In addition, lower pH values, higher proteolysis, and a decrease in toughness, elasticity and firmness were observed, as well as an increase in lactic, citric, and acetic acid contents. In contrast, no change was observed in the fatty acid profile. With respect to the sensory acceptance, the probiotic low-sodium Minas cheese presented scores above 6.00 (liked slightly) for the attributes flavor and overall acceptance. The addition of arginine can be a potential alternative for the development of probiotic dairy products with reduced sodium content.

Discrimination of Brazilian artisanal and inspected pork sausages: Application of unsupervised, linear and non-linear supervised chemometric methods

The performance of different chemometric approaches to discriminate artisanal and industrial pork sausages using traditional physicochemical parameters was investigated. A total of 90 samples of sausages marketed in various supermarkets and open-markets in Rio de Janeiro, Brazil were analyzed for their content of moisture, protein, fat, nitrite, sodium and calcium. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) were used as exploratory methods, while linear and non-linear classification methods, such as k-nearest neighbors (k-NN), soft independent modeling of class analogy (SIMCA), partial least square discriminant analysis (PLSDA) and artificial neural networks (ANN) were used for assessing the data. Different behaviors for all parameters were analyzed between the classes. Principal component analysis and hierarchical cluster analysis did not show a complete discrimination of the samples. KNN and ANN results showed excellent performance for both categories with 100% correct prediction while SIMCA and PLSDA presented performance of 100% and 85.7% for inspected and artisanal sausages, respectively. According to the SIMCA, PLSDA and ANN, the contents of moisture and fat showed the highest discriminative power. Overall, the findings emphasize the use of multivariate techniques to evaluate the quality of processed foods, as pork sausages.

Dulce de Leche, a typical product of Latin America: characterisation by physicochemical, optical and instrumental methods.

The physicochemical profile of Dulce de Leche (DL) was determined by both routine analysis and others techniques (HPLC, GC-MS and ICP-OES). Seven Brazilian commercial brands were characterised for moisture content, protein, fat, ash, pH and titratable acidity, mineral content (sodium, potassium, calcium, and phosphorus), colour parameters and instrumental analysis (carbohydrates content and volatile compounds). Overall, extensive variability among all the parameters evaluated were observed, suggesting different operational procedures in the dairy factories along the DL processing. In this sense, an increase of intrinsic quality of DL is related closely the standardization of operational parameters using during the manufacture.

Effect of galactooligosaccharide addition on the physical, optical, and sensory acceptance of vanilla ice cream

The effect of the addition of galactooligosaccharide (GOS) on the physicochemical, optical, and sensory characteristics of ice cream was investigated. Vanilla ice cream was supplemented with 0, 1.5, and 3.0% (wt/wt) GOS and characterized for pH, firmness, color, melting, overrun, as well as subjected to a discriminative sensory test (triangle test). For comparison purposes, ice creams containing fructooligosaccharide were also manufactured. The GOS ice creams were characterized by increased firmness and lower melting rates. Different perceptions were reported in the sensory evaluation for the 3.0% GOS ice cream when compared with the control, which was not observed for the fructooligosaccharide ice cream. Overall, the findings suggest it is possible to produce GOS ice cream with improved stability in relation to the physicochemical parameters and sensory perception.

Physicochemical evaluation of sheep milk yogurts containing different levels of inulin.

The present study aimed to evaluate the physicochemical parameters of sheep milk yogurt smoothies (SMY) containing inulin at different levels (0, 2, 4, and 6%). Titratable acidity and pH, yogurt bacteria counts, fatty acids profile, and healthy lipid indices were evaluated during 28 d of refrigerated storage. As expected for yogurts, Streptococcus thermophilus counts decreased 1 to 3 log cycles and Lactobacillus delbrueckii ssp. bulgaricus counts decreased 1 to 2 cycles from d 1 to 28. The protective effect of inulin on bacteria survival and viability in the food matrix was not verified in the prebiotic SMY during storage, regardless of inulin level. Although lower post-acidification was observed in prebiotic SMY due to inulin addition, no changes were verified in short-chain fatty acids (SCFA) or polyunsaturated fatty acids (PUFA). In contrast, an increase in medium- and long-chain fatty acids (MCFA and LCFA) and monounsaturated fatty acids (MUFA) was observed during storage in all SMY. The most significant levels of fatty acids in SMY were oleic acid, followed by palmitic and myristic acids. A high positive correlation between conjugated linoleic acid (CLA) and oleic acid (r=0.978) was observed. The cis-9,trans-11 CLA isomer represented approximately 78% of total PUFA and 2% of total fatty acids, whereas α-linoleic acid comprised about 22% PUFA and 1% of total fatty acids in SMY. The fatty acid changes during storage were associated with the metabolic activity of the starter bacteria, especially for oleic acid and cis-9,trans-11 CLA isomer. Thus, the SMY represented a great source of these compounds. We observed that inulin levels did not affect fatty acids. A nonsignificant decrease in atherogenic index was observed during storage in all SMY, and a positive correlation (r=0.973) was found between atherogenic index and thrombogenic index of SMY. High correlations were observed between lauric and myristic acids and saturated fatty acids (r=0.907 and r=0.894, respectively), providing evidence of their atherogenic and thrombogenic potential. A negative correlation was observed between stearic acid and atherogenic index (r=-0.612) and between oleic acid and atherogenic index. Sheep milk yogurt could be characterized as a food with low atherogenic and thrombogenic risk because of its healthy lipid composition. Therefore, addition of inulin to SMY could be a good option to improve functionality of this food matrix for dairy companies wishing to enter the functional food market.

The effect of carbon dioxide on the shelf life of ready-to-eat shredded chicken breast stored under refrigeration

The objective of the present study was to determine the shelf life of ready-to-eat cooked chicken breast fillets (shredded) stored in atmospheres that were modified with different concentrations of CO2 and to establish a relationship between the concentration of this gas and bacterial growth. The samples were divided into 7 groups with different packaging conditions: aerobiosis, vacuum, and 10, 30, 50, 70, and 90% CO2 (with the remaining volume filled with N2). All of the samples were stored at 4 ± 2°C for 28 d. During this period, pH tests and counts of aerobic heterotrophic mesophyll bacteria (AHMB), aerobic heterotrophic psychotropic bacteria (AHPB), Enterobacteriaceae, and lactic acid bacteria (LAB) were performed, and the gas compositions of the packaging atmospheres were verified. The pH of the aerobic packages increased during storage. However, the other treatments resulted in the opposite trend, with the CO2 concentration decreasing over the first 24 h and then remaining constant until the end of experiment. A gradual increase in the AHMB, AHPB, Enterobacteriaceae, and LAB counts was observed during storage; this increase was faster in the meat that was packed under aerobiosis conditions than in the other treatments. The treatments with a CO2 concentration above 10% exhibited lower Enterobacteriaceae growth, whereas LAB growth was discrete in all of the treatments, independent of the CO2 concentration. The shelf life of the samples packed with 90% CO2 was 28 d. Based on the AHMB and AHPB counts, the shelf life was 3 times longer than for the samples packed under aerobiosis conditions (9 d). The increased package CO2 concentration caused a reduction in the growth rate of the examined bacteria (r = 0.99), and treatment with 90% CO2 appears promising as a method with which to increase the products shelf life.

Effect of high-dose irradiation on quality characteristics of ready-to-eat broiler breast fillets stored at room temperature

The effect of high-dose irradiation on the physical, chemical, and bacteriological parameters of ready-to-eat vacuum-packed broiler breast meat after 430 d of storage at room temperature was investigated. Ready-to-eat broiler breast fillets were immersed in brine with garlic powder and then drained, grilled, and vacuum-packed (primary packaging). The high-dose irradiation used was approximately 48 kGy. The treatments were designated as A (irradiated samples stored at room temperature), B (irradiated samples stored at -25°C), and C (nonirradiated samples stored at -25°C). All samples were packaged in polyethylene bags containing aluminum to exclude light (secondary packaging). Proximate composition, pH, 2-thiobarbituric acid reactive substance (TBARS), and heterotrophic aerobic mesophilic bacteria were analyzed during 430 d of storage. Results were analyzed using 1-way ANOVA and the Tukey test. Linear regression was used to analyze the correlation between the results for each parameter and storage time of the different treatments. The gamma radiation caused slight changes (P < 0.05) in the moisture and fat content, regardless of storage temperature. After storage d 110, TBARS values remained stable (P > 0.05) in all the treatments. The preservation methods used were effective in maintaining the mesophilic counts below the detection level during the entire storage period. We concluded that, among the treatments studied, high-dose irradiation with storage at room temperature showed potential for the preservation of ready-to-eat products made from poultry meat, to provide foods safe for consumption.

Meat characteristics of cattle fed diets containing whole cottonseed

Sensory and instrumental analyses evaluated the meat and fat characteristics of feedlot-finished steers fed a diet containing cottonseed. Global impression, texture, meat color, and fat color were assessed. Thirty Nellore bulls with an average age of 30 ± 6 months and initial body weight of 382.7 ± 28.4kg were kept in feedlot stalls and fed the following cottonseed levels: 0; 2.22 %; 4.44 %; 6.66 %; 8.88 %; 11.11 % of the dietary dry matter. The cottonseed used in this experiment had an average free gossypol content of 4.5g/kg of cottonseed. The overall impression of the samples, assessed by the triangle test for difference, did not differ for more than 62 % of the panelists (P>0.01). The shear strength of roasted meat varied from 6.00 to 6.54kg. According to texture profile analysis (TPA), the hardness, springiness, and chewiness of roast meat ranged from 24.15 to 28.01 N, 0.52 to 0.56, 8.42 to 11.01 N, respectively; of raw meat, 9.51 to 13.86 N, 0.26 to 0.29, and 1.38 to 1.81 N, respectively. The different treatments did not affect meat texture, meat color, or fat color (P>0.05). Meat color, luminosity, and red intensity ranged from 37.71 to 42.85, 20.68 to 25.25, and 6.74 to 8.61, respectively; fat color, luminosity, and yellow intensity ranged from 62.26 to 63.78, 11.13 to 11.62, and 10.53 to 10.86, respectively. Cottonseed intake of up to 1.13kg/animal/day, equivalent to a free gossypol intake of 5.05g/animal/day, in place of soybean meal and ground corn, did not significantly change the global sensory impression, texture, and color of the meat and fat.