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Cheese ripening involves lactose metabolism, lipolysis and proteolysis, which are affected by many factors. The aim of this study was to assess changes due to ripening (90 days) of goat milk cheese through bacteriological and physicochemical analysis in order to verify if, at the end of ripening period, this cheese could be considered “lactose-free”. Three batches of the goat milk cheese were manufactured and ripened at 10 °C and 80% relative humidity for 90 days. Titratable acidity increased by about 59 °D due to carbohydrate degradation and organic acid production. However, pH (5.31–5.25) remained constant. Lactococcus was the dominant cheese microbiota, acting in the fermentation of lactose (1.17–0.06 mg/g) and lactic acid production (5.49–s10.01 mg/g). Thus, ripening time was decisive for bacteriological and physicochemical goat milk cheese characteristics. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s10068-019-00682-w) contains supplementary material, which is available to authorized users.

The aim of this study was to assess the chemical quality and instrumental texture parameters, as well as their relationships, of five Brazilian freshwater fish species stored at 4 °C for 6 days. In general, ammonia, TCA-soluble peptides, and biogenic amine values increased with storage time, attributed to the advance of the deterioration process. Ammonia and TCA-soluble peptide concentrations correlated positively with the increase of putrescine, spermine, and histamine. Putrescine production began during the first days of storage, while cadaverine was produced later. Spermine and spermidine showed variable behavior, increasing and decreasing, respectively. With regard to the instrumental texture parameters, firmness, hardness, and chewiness decreased at the beginning of the storage period, whereas an increase was observed in springiness. All instrumental texture parameters demonstrated high correlations with ammonia and TCA-soluble peptides. The increase in certain biogenic amines (putrescine, cadaverine, and spermine) seems to correlate well with decreases observed in firmness, hardness, and chewiness. In addition, a strong relationship was observed between the initial days of storage and instrumental texture parameters, while a significant correlation between the end of the storage and the chemical quality analyses was verified. Firmness, hardness, chewiness, and cohesiveness were considered parameters with high potential in the evaluation of fish freshness during the first days of storage, whereas the chemical quality analyses and springiness were considered important for later evaluation of fish quality. Therefore, instrumental texture parameters may be used as quality indicators in the evaluation of freshwater fish freshness.

The aim of the present study was to compare the color and oxidative stability of light (LM) and dark (DM) muscles of Nile tilapia (Oreochromis niloticus) stored at 4 °C for eight days. Five different trials of LM and DM samples were analyzed for instrumental color attributes (lightness, redness and yellowness), including the surface color stability through ratio of reflectance at 630/580 nm (R630/580), myoglobin concentration, total lipid content, fatty acid profile, metmyoglobin reducing activity (MRA), pH, lipid oxidation and protein oxidation. Results of the present study indicated that DM of Nile tilapia (Oreochromis niloticus) present lower oxidative and color stability during refrigerated storage than LM. RESUMO: O objetivo do presente estudo foi comparar a estabilidade de cor e oxidativa de músculos claros (LM) e escuros (DM) de tilápia do Nilo (Oreochromis niloticus) armazenados a 4° C por oito dias. Cinco repetições diferentes de amostras de LM e DM foram analisadas quanto aos atributos instrumentais de cor (luminosidade, teor de vermelho e teor de amarelo), incluindo a estabilidade de cor na superfície através da razão de refletâncias nos comprimentos de onda 630 e 580 nm (R630/580), concentração de mioglobina, lipídios totais, perfil de ácidos graxos, atividade de redução da metamioglobina (MRA), pH, oxidação lipídica e oxidação proteica. Os resultados do presente estudo indicam que músculos escuros (DM) de tilápia do Nilo (Oreochromis niloticus) apresentam menor estabilidade oxidativa e de cor durante o armazenamento refrigerado, quando comparados aos músculos claros (LM).

Although the demand for goat milk products has been growing, they have lower consumer acceptability than products derived from cow milk. However, the addition of cupuassu pulp can be used to improve the formulation of these products. For this reason, the aim of this study was to investigate the influence of new goat milk yogurt manufactured with cupuassu pulp on physicochemical properties, consumers' perceptions, and overall consumer acceptance. In addition, the effect of antioxidant health information on consumer acceptance and purchase intention of cupuassu goat milk yogurts was evaluated. The results demonstrated a positive expectation regarding linking and familiarity to goat milk products and products with cupuassu pulp. The pH, total phenolic content, lightness, redness, yellowness, and apparent viscosity were potentially affected by the addition of cupuassu, with the highest concentration of cupuassu (10%) exhibiting the greatest changes in parameters. Based on principal component analysis, partial least squares regression, and just-about-right and penalty analysis, the addition of cupuassu pulp improved some sensory attributes of goat milk yogurt, such as cupuassu aroma, cupuassu flavor, yellow color, consistency, and viscosity, which positively influenced product acceptance. In addition, antioxidant health information increased the acceptance and purchase intention of cupuassu goat milk yogurts. Taking into account the parameters investigated in this study, the best scoring formulation was goat milk yogurt with 10% cupuassu pulp. Our results suggest that cupuassu pulp can be considered a potential ingredient to improve the sensory and texture properties of goat milk yogurt. Furthermore, the antioxidant health information could be a sensory strategy to increase the acceptance of cupuassu goat milk yogurts.

Colossoma macropomum x Piaractus mesopotamicus (CP) is a freshwater fish with greatest commercial importance in Brazil. Fillets of CP are highly perishable food and preservation technology with UV-C could improve food safety and extend shelf life. Fillet samples were submitted at UV-C (55.83mJ/cm2) and examined for mesophilic and psychrotrophic count and biogenic amines over 6 days. UV-C reduced the bacterial growth and number of colonies in the stationary phase; also increase the levels of cadaverine, putrescine and histamine. The results suggest that UV-C enhanced the shelf-life of CP fillets by at least 50%.

Biogenic amines (BAs) are low-molecular-weight organic bases, which possess biological activity. In food, the presence of BAs as histamine and tyramine is a public health concern being the most notorious food-borne intoxications. BAs can be detected in raw and processed foods that are formed and degraded through several pathways during the metabolic processes of animals, plants, and microorganisms. The BAs analyses are very important because they are considered as indicators of food quality and safety. Some bacteria are usual contaminants of food and have been described with the ability to produce BAs, which can be the result of failures in manufacturing practices, poor quality, or insufficient hygienic conditions. Hence, BAs can be used as a quality index for meat, fish, and dairy products. In addition, some lactic acid bacteria strains can also contribute to BAs production and this group is mainly responsible for their synthesis in fermented foods. Consequently, the control of BAs in food is a challenge for the food industry.

The proximate composition and fatty acid (FA) profiles of five Brazilian freshwater fish species, namely Brycon cephalus (BC), Cichla ocellaris (CO), Prochilodus lineatus (PL), Leporinus friderici (LF) and Pseudoplatystoma corruscans (PCO), were investigated. CO and LF exhibited the highest (p < 0.05) moisture content, as well as one of the lowest (p < 0.05) lipid values, whereas BC presented the lowest (p < 0.05) moisture and, alongside PL, the highest (p < 0.05) lipid content. The predominant FAs in the evaluated fish species were palmitic, oleic, linoleic and docosahexaenoic acids. BC and CO presented high n-3 PUFA content, especially DHA, and demonstrated superior nutritional quality indices compared to the other evaluated fish species. Furthermore, a significant relationship was observed among these species, suggesting they possess similar nutritional lipid values. Thus, BC and CO were proven to be an excellent matrix with relevant lipid quality, desirable for human health.

The aim of this Research Communication was to investigate the changes in physicochemical, colour, apparent viscosity and texture properties in low-fat goat milk yogurts prepared with cupuassu pulp by the addition of inulin (SI), maltodextrin (SM), whey protein (SW) and skim milk powder (SP). Three batches of each cupuassu goat milk yogurt were prepared and analysed on the 1st day of storage by pH, proximate composition, colour, apparent viscosity, and texture. In comparison to yogurts from whole (W) or skimmed milk (S), all of the fat replacers improved the physicochemical properties (P < 0·05). The addition of the carbohydrates (inulin and maltodextrin) and proteins (whey protein and skim milk powder) also influenced the colour of the low-fat cupuassu goat milk yogurt (P < 0·05). All fat replacer treatments (SI, SM, SW and SP) presented a higher (P < 0·05) apparent viscosity than W and S yogurts. However, only the addition of skim milk powder increased the texture parameters (firmness and consistency) (P < 0·05). These results suggest that skim milk powder can be used to improve the texture properties of low-fat cupuassu goat milk. Furthermore, inulin, maltodextrin, and whey protein can potentially be applied in the goat dairy industry to increase the viscosity of yogurts.

The aim of this study was to determine the potential for waste extracts from the pequi (Caryocar brasiliense) and juçara (Euterpe edulis) to reduce oxidatiove processes in antibiotic-free broiler meat. The use of natural antioxidants extracted from fruit-processing wastes has been neglected. Although these residues contain high amounts of these bioactive compounds, they are often discarded by industry. Meat samples were exposed previously submitted to UV-C radiation at 1.161 mW / cm2 for 10 minutes to accelerate the rancidity process. Pequi and juçara waste extracts were obtained by microwave-assisted extraction (MAE). A total of four conditions were tested using antibiotic-free broiler thighs and drumstick meat: BN-with no antioxidant (negative control), BP-with BHT (Butylated hydroxytoluene) (positive control), BE-with juçara extract, BC-with pequi extract. The color, pH, lipid and protein oxidation (days 0, 2, 4, 6, 8 and 10), antioxidant contents and activity (days 0 and 10), and proximal composition and fatty acid profile (day 0) were tested, followed by principal component analysis (PCA). Pequi waste extract presented the highest antioxidant content and activity. BE and BC treatments presented the highest total phenolic (TPC) and flavonoid (TFC) content, and BE presented the highest total monomeric anthocyanin content (TAC). TFC increased during storage in all treatments. The waste extracts of C. brasiliense presented the highest antioxidant activity against lipid oxidation in the antibiotic-free broiler meat. Moreover, both extracts presented high antioxidant activity against protein oxidation. Although the pequi peel extract had a better effect in terms of suppressing both types of oxidation, either this extract or the jussara waste extract could be used as a technological strategy to reduce the oxidative processes in antibiotic-free broiler meat for the poultry industry. Thus, waste extracts can be a potential technology to reduce the oxidative processes in antibiotic-free broiler meat.

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.

The Euterpe edulis (Juçara) is native to Brazil, which berries and wastes present high antioxidant content. Therefore, in this study, microwave-assisted extraction (MAE) was investigated for antioxidant compounds extraction from E. edulis waste and maximized antioxidant activities using response surface methodology coupled with a central composite design. Three factors were observed: microwave power (400/500/600 W), exposition time (30/60/90 sec) and ethanol concentration solvent (40/60/80%). The extracts were characterized by determination of total phenolic (TPC), flavonoids (TFC), monomeric anthocyanins (TAC), tannins content (TTC), and in vitro antioxidant assay (AA%). The yield of TPC, TFC, TAC, and TTC varied at 595.43-2171.34 mg GAE.100 g DM-1, 137.36-251.24 mg QE.100 g DM-1, 179.32-354.38 mg C-3-GE.100 g DM-1 and 0.23-1.00 µg TAE.100 g DM-1, respectively. The optimal MAE parameters for TPC was microwave power 668.18 W, exposition time 110.45 s and aqueous ethanol concentration 93.64%, for TFC same parameters observed; though for TAC the different parameters were 532.28 W, and for TTC 9.55 s. However, for antioxidant activity, the parameters were 668.18 W, 110.45 s time and 64.41% of aqueous ethanol solvent. Therefore, this methodology was successfully applied for optimal extraction of total phenolics, flavonoids, monomeric anthocyanins and tannins from juçara waste and obtain optimal antioxidant activity.

The effects of UV-C radiation on the microbiological and chemical quality of hybrid Colossoma macropomum × Piaractus mesopotamicus fillets were examined daily over a period of 6 days. The samples were submitted to three different packaging conditions: (VP) vacuum packaging; (UV-L) VP+UV-C radiation at lower dose (55.83 mJ/cm2); or (UV-H) VP+UV-C radiation at higher dose (160.97 mJ/cm2). The microbial groups examined presented lower growth rate as well as lower number of colonies in the stationary phase in samples submitted to UV-L and UV-H when compared to VP. The UV-C radiation (UV-L and UV-H) accelerated TVB-N and improved biogenic amine production, while preventing a major production of ammonia in fish samples. The results of the current study suggest that UV-C radiation enhanced the shelf-life of Colossoma macropomum × Piaractus mesopotamicus fillets by at least 50% by slowing down microbial growth parameters and delaying chemical changes. Practical Applications Nonthermal technologies are being applied as a viable alternative to thermal techniques, frequently used in processing of fresh food products. UV-C radiation is a new nonthermal technique that can lead to superficial decontamination of fresh fish fillets and presents low-cost as well as easy implementation in food processing industries. This technology does not produce any reactivity, chemical waste or undesirable by-products. However, there are few data on the use of this technique in food processing, mainly in fish products. Thus, this study will provide key information for the control of the microbial growth and chemical compounds production originated during vacuum-packed fish spoilage.

Effects of modified atmosphere packaging (MAP) in combination to UV-C radiation on rainbow trout fillets were examined. The samples were submitted to two treatments: (T1) aerobic package; (T2) MAP+UV-C radiation (80% CO2/20% N2; 106.32mJ/cm2) and were analyzed daily for microbiological (mesophilic and psychrotrophic count) and chemical (biogenic amines) parameters. MAP+UV-C radiation (T2) promoted lag phase formation and lower number of colonies in the stationary phase as well as retarded cadaverine production during storage time. MAP+UV-C radiation retard microbial growth and delay chemical changes enhancing the shelf life of rainbow trout fillets by at least twice.

The effects of UV-C radiation, modified atmosphere packaging (MAP) and their combination on rainbow trout (Oncorhynchus mykiss) fillets quality were examined during a period of 22 days. The samples were submitted to five packaging conditions: (AP) aerobic packaging; (VP) vacuum packaging; (VP + UV-C) vacuum packaging + UV-C radiation; (MAP) modified atmosphere packaging (80% CO2/20% N2) and (MAP + UV-C) modified atmosphere packaging + UV-C radiation (80% CO2/20% N2; 106.32 mJ/cm2) and storaged at 4 °C. The samples were analyzed daily for microbiological (mesophilic, psychrotrophic and Enterobacteriaceae counts) and chemical (pH, TMA-N, TBV-N, lipid oxidation, ammonia and biogenic amines) parameters. Overall, UV-C radiation promoted lag phase formation in mesophilic and psychrotrophic groups. Mesophilic and psychrotrophic groups presented significant lower (P