Robson Maia Franco

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.

Campylobacter jejuni/coli : Methodology of isolation and possible interfering factors in primary culture

The prevalence of Campylobacter jejuni and Campylobacter coli was investigated in 64 samples of fresh retail chicken purchased from commercial slaughterhouses located in Brazil. Campylobacter spp. were isolated from 40 (62.5%) of 64 analyzed samples. The strains biotyped according to Lior were classified as C. jejuni biotypes I and II, and C. coli biotypes I and II. The efficiency of different procedures for recovering Campylobacter spp. from chicken carcasses was tested. The enrichment procedure was significantly less effective than direct plating (P < 0.05), detecting 19 of 40 (47.5%) as opposed to 38 of 40 (95%) positive samples. Using direct plating the efficiency of Blasers selective supplement was significantly more effective (P < 0.05) than Skirrows selective supplement. To verify which factors could be affecting Campylobacter spp. growth in enrichment broth, the pH was measured after incubation for 48 h at 42°C and lactobacilli, coliforms, and enterococci were enumerated. Most of the Campylobacter -negative samples presented high levels of indicator microorganisms, which may have hindered the recovery of Campylobacter spp. during the enrichment procedure.

Partial substitution of NaCl by KCl and addition of flavor enhancers on probiotic Prato cheese: A study covering manufacturing, ripening and storage time

Cheese is a suitable matrix to deliver probiotic strains but it contains a high amount of sodium. The effect of partial substitution of NaCl by KCl and the addition of flavor enhancers (l-arginine, yeast and oregano extract) on probiotic Prato cheese was investigated after 1, 30, and 60 d of refrigerated storage (immediately after manufacturing, and during ripening and storage). Microbiological (lactic acid bacteria and probiotic Lactobacillus casei 01 counts and survival under gastrointestinal conditions), physicochemical (pH, proteolysis, fatty acids), bioactivity (antioxidant effect and angiotensin I-converting enzyme inhibitory activity), rheological, and water mobility by means of time domain low-field nuclear magnetic resonance were investigated. Significant changes in probiotic survival were observed; however, the sodium reduction and the addition of flavor enhancers did not constitute an obstacle to L. casei 01 (>108 CFU/g) during storage. Slight changes were observed in proteolysis, bioactivity, water mobility, texture profile, and fatty acids of the cheeses as a function of the flavor enhancer added. The sodium reduction and the supplementation of Prato cheese with probiotic cultures may be an effective alternative to the production of a potentially functional cheese.

The addition of inulin and Lactobacillus casei 01 in sheep milk ice cream

The effect of the Lactobacillus casei 01 and inulin addition on sheep milk ice cream during storage (-18 °C, 150 days) was investigated. Control, probiotic and synbiotic ice cream (10% w/w sheep milk cream; 10% w/w sheep milk cream, L. casei 01, 6 log CFU/mL; 10% w/w inulin, L. casei 01, 6 log CFU/mL, respectively) were manufactured. Microbiological counts (probiotic count, survival after in vitro gastrointestinal resistance, Caco-2 cell adhesion), bioactivity and microstructure were analysed. Physical and textural characteristics, colour parameters, thermal analysis and organic acids/volatile compounds were also evaluated. All formulations supported L. casei 01 viability and maintained above the minimum therapeutic level (>6 log CFU/mL) during storage. Inulin did not affect L. casei 01 survival after the passage through simulated gastrointestinal tract and adhesion to Caco-2 cells while improved the ACE-inhibitory and antioxidant activity. L. casei 01 addition produced several volatile compounds, such as carboxylic acids, alcohols, aldehydes and ketones. Also, scanning electron microscopy showed an interaction between probiotic bacteria and inulin fibre on synbiotic ice cream and the adhesion of L. casei to Caco-2 cells was observed.

Effects of ultraviolet light on biogenic amines and other quality indicators of chicken meat during refrigerated storage

Radiation from UV-C has been demonstrated as a potential surface decontamination method in addition to several advantages over regular sanitation methods. However, UV-C radiation possibly affects the physicochemical properties of meat products. To determine the optimum exposure time for bacterial reduction, 39 chicken breasts, inoculated with a pool of Salmonella spp., were submitted to 3 levels of UV-C intensities (0.62, 1.13, and 1.95 mW/cm²) for up to 120 s. After the optimum exposure time of 90 s was determined, changes in the biogenic amines, total aerobic mesophilic bacteria, Enterobacteriaceae, lipid oxidation, pH, and instrumental color were evaluated in 84 chicken breasts that were irradiated (0.62, 1.13, and 1.95 mW/cm²) and stored at 4°C for 9 d. The groups treated with UV-C radiation exhibited an increase in tyramine, cadaverine, and putrescine contents (P < 0.05). The highest UV-C intensity (1.95 mW/cm²) promoted a decrease in the initial bacterial load, and extended the lag phase and the shelf life. The groups irradiated with 1.13 and 1.95 mW/cm² exhibited a more stable b* value than the other groups; similar trends for L*, a*, pH, and TBA reactive substance values were observed among all groups. The UV-C light was demonstrated to be an efficient alternative technology to improve the bacteriological quality of chicken meat without negatively affecting the physical and chemical parameters of chicken breast meat. Nonetheless, the increases on the biogenic amines content should be considered as an effect of the UV processing and not as an indicator of bacterial growth.

Cupuassu (Theobroma grandiflorum) pulp, probiotic, and prebiotic: Influence on color, apparent viscosity, and texture of goat milk yogurts

Cupuassu is an acidic fruit that has a characteristic aroma, flavor, and texture; its fiber-rich pulp can provide a different consistency than other fruit pulps. Goat milk is an excellent source of amino acids, fatty acids, and minerals, and is widely used for processing fermented milks, such as yogurt. However, compared with cow milk yogurts, it is difficult to make goat milk yogurts with a good consistency. Therefore, it is necessary to use certain technological strategies. This study was carried out to investigate the possibility of adding cupuassu pulp, probiotic (Lactobacillus acidophilus LA-5), and prebiotic (inulin) to improve the texture of goat milk yogurt. A total of 6 treatments were performed: natural (N), probiotic (Pro), prebiotic (Pre), synbiotic (S), cupuassu (C), and probiotic with cupuassu (PC). The viability of probiotic in yogurts (Pro, S, and PC) was evaluated. In addition, instrumental analyses (pH, color, apparent viscosity, and texture) were performed to evaluate the influence of these different ingredients on goat milk yogurts. The probiotic bacteria remained viable (≥7 log cfu·mL(-1)) throughout the 28d of refrigerated storage, which exceeded the minimum count required to confer probiotic physiological benefits. The pH levels of the yogurts inoculated with L. acidophilus (Pro, S, and PC) were lower than others yogurts (N, Pre, and C). However, all yogurt samples underwent gradual decreases in pH until 7 to 14d of storage. The lightness (L*) was affected initially by addition of all ingredients (cupuassu pulp, probiotic, and prebiotic). The addition of cupuassu pulp (C and PC) increased the L* during the period of storage. Apparent viscosity and firmness decreased in the PC yogurt. The consistency was highest in the yogurts with added prebiotic (Pre and S) than the other yogurts (N, Pro, C, and PC) at the end of the storage period (d 28). The cohesiveness remained constant in all yogurts (N, Pro, Pre, S, C, and PC). Based on the results obtained from the current study, it was concluded that cupuassu pulp addition improves the texture of goat milk yogurts. Therefore, this pulp could be an important technological strategy for the dairy goat industry.

Sensory evaluation of ovine milk yoghurt with inulin addition

The purpose of this study was to elaborate prebiotic yoghurt using ovine milk and different inulin concentrations (0, 2 and 6%). Samples were submitted to laboratory analysis and two sensory tests with 100 consumers. The results of apparent viscosity and firmness determined by instrumental analysis of each yoghurt and control differed significantly. Just-About-Right showed consistency as the main attribute that varied in treatments. According to penalty analysis, prebiotic yoghurt containing 6% inulin had minor penalties, which indicates its advantage in the quest to better consumer demands. Hence, this treatment demonstrated better results as well as the many prebiotic benefits associated with an adequate fibre amount.

Effect of sodium reduction and flavor enhancer addition on probiotic Prato cheese processing

The effect of partial substitution of NaCl with KCl and the flavor enhancers addition (arginine, yeast extract and oregano extract) on Probiotic Prato cheese processing with (L. casei 01, 7logCFU/mL) was investigated. Microbiological (lactic acid bacteria and probiotic counts), physicochemical (proximate composition, pH, proteolysis), bioactivity (antioxidant and angiotensin I-converting enzyme inhibitory activity), rheological (uniaxial compression and creep tests), water mobility (time domain low field magnetic resonance), microstructure (scanning electron microscopy) and sensory evaluation (consumer test) were performed. Sodium reduction and flavor enhancers addition did not constitute an obstacle to the survival of lactic and probiotic bacteria. Proximate composition, antioxidant and angiotensin I-converting enzyme inhibitory activity, and the rheological parameters were affected by the addition of flavor enhancer. No change in the fatty acid profile of cheeses was observed while good performance in the consumer test was obtained by the addition of yeast extract and oregano extract. Prato cheese can be an adequate carrier of probiotics and the addition of different flavor enhancers can contribute developing this functional product in the cheese industry.

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.

Microbiology, sensory evaluation and shelf life of irradiated chicken breast fillets stored in air or vacuum

This work investigated the effects of different packaging methods (air and vacuum) combined with irradiation (0.0, 2.0 and 3.0 kGy) on the preservation of chicken breast fillets stored at 1oC for up to 18 days by sensorial test, determination of pH and bacterial growth. The findings indicated that the post-irradiation lag phase increased with the dose, leading to an extension in shelf-life. Vacuum-packed samples irradiated at 3.0 kGy exhibited the longest shelf life. Among the analyzed bacteria, coliforms and Listeria spp. were most sensitive to gamma radiation. All the fillets acquired more attractive coloration and better overall impression with irradiation. The combined use of vacuum packaging and irradiation (3.0 kGy) reduced the microbial populations without causing change in pH and yielded a significant shelf-life extension of refrigerated fillets, besides improving its appearance.