Fat replacement by green banana biomass: Impact on the technological, nutritional and dynamic sensory profiling of chicken mortadella.

Reducing the fat content of processed meat products has become necessary due to consumer-driven demand for healthier foods. In this sense, this study aimed to characterize chicken mortadella with total and partial replacement of chicken skin by green banana biomass (GBB). Five treatments (with two repetitions each and weighing 400 g) were prepared: F0 (control treatment formulated with 100% chicken skin), F1, F2, F3, and F4 (25, 50, 75, and 100% of chicken skin replacement by GBB, respectively). Samples were characterized according to physicochemical composition - approximate composition, energy value, pH, water activity (Aw), emulsion stability (ES), water-holding capacity (WHC), instrumental color (L*, a* and b*), instrumental texture, fatty acid profile, and microstructure) - nutritional quality and sensory properties (dynamic profiling by Temporal Check-all-that-apply and acceptance). The replacement of 100% chicken skin by GBB increased the WHC of mortadella and did not affect the ES in all formulations. The addition of GBB did not affect the typical mortadella flavor of the samples, and the dominance of the flavor was directed towards the fibrous and fat flavor attributes. In addition, all formulations had acceptance scores above 6.5. Based on the results, replacement up to 100% of chicken skin with GBB is possible and obtains a healthier emulsified meat product with good sensory acceptance.

Potentially probiotic or postbiotic pre-converted nitrite from celery produced by an axenic culture system with probiotic lacticaseibacilli strain.

The present study evaluated the use of the probiotic Lacticaseibacillus paracasei DTA-83 as a nitrite-reducing agent to produce potentially probiotic or postbiotic pre-converted nitrite from celery. The results obtained were compared to those achieved by direct addition of sodium nitrite for the typical reddish color formation in cooked pork sausages and the inhibitory potential against the growth of target microorganisms, including the clostridia group. Regarding the sausages color, similar findings were observed when comparing the use of pre-converted nitrite from celery produced by L. paracasei DTA-83 and the direct addition of sodium nitrite. Additionally, it presented an inhibitory effect against Salmonella spp., which was not observed with the direct addition of nitrite, revealing a potential strategy to control salmonellosis in the matrix. However, a non-equivalent preservative effect against Clostridium perfringens (INCQS 215) was determined. The results highlight a promising alternative to produce probiotic or postbiotic meat ingredients; however, further studies should be conducted to investigate doses that achieve microbial control.

Hot topic: Holder pasteurization of human milk affects some bioactive proteins.

The aim of this research was to investigate the effect of Holder pasteurization (HoP; 62.5°C, 30 min) on the protein profile and activities of glutathione peroxidase (GPx) and lysozyme (LZ) in human milk. Over 6 mo of lactation, human milk samples were analyzed before (raw) and after HoP for GPx and LZ activity and electrophoresis protein profile. Holder pasteurization reduced human milk lactoferrin, immunoglobulin fractions, and GPx activity. In addition, GPx activity, which is high in colostrum and transitional milk, was naturally reduced over the 6-mo lactation period. In contrast, HoP did not affect human milk LZ activity. Besides its critical cellular antioxidant role in protecting the organism from oxidative damage, GPx decreases the redox potential of milk, stimulating the growth of anaerobic microorganisms, such as the probiotic Bifidobacterium. Considering the role of lactoferrin in infant health, we conclude that an important part of its function has been inactivated by pasteurization. These compounds should be replaced by human milk banks after the HoP step to recover lost functionality. Otherwise, an alternative technology to HoP that better retains human milk properties should be used by milk banks to eliminate the risk of transmission of infectious agents.

Psychrotrophic bacteria in milk: How much do we really know?

The occurrence of psychrotrophic bacteria in raw milk is studied worldwide due to the difficulties associated with controlling their growth during cold storage and the consequent negative effects upon fluid milk or dairy products. Among the psychrotrophic bacteria, the genus Pseudomonas (represented primarily by P. fluorescens) has been highlighted as the cause of numerous defects in dairy products. In light of its perceived predominance, this species has frequently been chosen as a model organism to assess the effects of psychrotrophic bacteria on milk or to evaluate the efficacy of control measures. However, recent findings derived from the application of molecular biological techniques have exposed a number of deficiencies in our knowledge of the biology of milk-associated psychrotrophs. Furthermore, it has been revealed that microbe to microbe communication plays a significant role in determining both the identities and the extent to which different groups of microbes develop during cold storage. The application of molecular identification methods has exposed errors in the classification of members of the genus Pseudomonas isolated from cold stored milk and has stimulated a reevaluation of the presumed status of P. fluorescens as the predominant milk-associated psychrotrophic species. This article presents a succinct review of data from studies on psychrotrophic bacteria in milk, some of which contest established theories in relation to the microbiology of cold stored raw milk, and poses the question: how much do we really know?

Psychrotrophic bacteria in milk: How much do we really know?

The occurrence of psychrotrophic bacteria in raw milk is studied worldwide due to the difficulties associated with controlling their growth during cold storage and the consequent negative effects upon fluid milk or dairy products. Among the psychrotrophic bacteria, the genus Pseudomonas (represented primarily by P. fluorescens) has been highlighted as the cause of numerous defects in dairy products. In light of its perceived predominance, this species has frequently been chosen as a model organism to assess the effects of psychrotrophic bacteria on milk or to evaluate the efficacy of control measures. However, recent findings derived from the application of molecular biological techniques have exposed a number of deficiencies in our knowledge of the biology of milk-associated psychrotrophs. Furthermore, it has been revealed that microbe to microbe communication plays a significant role in determining both the identities and the extent to which different groups of microbes develop during cold storage. The application of molecular identification methods has exposed errors in the classification of members of the genus Pseudomonas isolated from cold stored milk and has stimulated a reevaluation of the presumed status of P. fluorescens as the predominant milk-associated psychrotrophic species. This article presents a succinct review of data from studies on psychrotrophic bacteria in milk, some of which contest established theories in relation to the microbiology of cold stored raw milk, and poses the question: how much do we really know?.

Inhibitory effect of acetic acid on bioconversion of xylose in xylitol by Candida guilliermondii in sugarcane bagasse hydrolysate

Hidrolisado de bagaço de cana-de-açúcar contendo uma concentração inicial de ácido acético de 3,5g/L foi utilizado como meio de fermentação para a bioconversão de xilose em xilitol pela levedura Candida guilliermondii FTI 20037. Ácido acético (2,0g/L) foi adicionado ao meio em diferentes tempos de fermentação, com o objetivo de avaliar o efeito deste ácido neste bioprocesso. O maior efeito inibitório deste ácido na bioconversão de xilose em xilitol pela levedura ocorreu quando este foi adicionado ao meio após 12h de fermentação. Nesta condição observou-se uma redução de 23,22 porcento e 11,24 porcento, respectivamente, no consumo de xilose e no crescimento celular em relação à fermentação em que a adição deste ácido ocorreu no tempo inicial de incubação. Como conseqüência do efeito inibitório, observou-se os menores valores de rendimento (0,39g/g) e produtividade (0,22g/L.h) de xilitol, correspondendo a uma redução de 36 e 48 porcento, respectivamente, em relação aos valores obtidos com a adição de ácido acético nos outros tempos de fermentação. Os resultados obtidos permitem concluir que, nas condições experimentais empregadas neste trabalho, o efeito inibitório do ácido acético sobre a bioconversão de xilose em xilitol é dependente do tempo de fermentação em que a adição do ácido foi feita e não apenas de sua concentração no meio.

Avaliaçäo da sensibilidade de microrganismos selecionados a diferentes concentraçöes de nisina em salsichas comum e de frango / Evaluation of sensibility sausages and poultry sausages

Salsichas de frango e comuns foram tratadas por imersäo em soluçöes contendo diferentes concentraçöes de nisina (0, 25, 50 e 100 UI mL-1) e, à seguir, inoculadas por imersäo em suspensäo de células do microrganismo a ser testado (Brochothrix thermosphacta, Weissella viridescens, Leuconostoc mesenteroides e Listeria monocytogenes), embaladas à vácuo e incubadas a 5§C por 12 dias. Determina a menor concentraçäo de nisina capaz de conter eficazmente o desenvolvimento dos microrganismos selecionados nos dois tipos de salsichas. B. thermosphacta e W. viridescens foram os microrganismos que apresentam a maior sensibilidade, sendo a menor concentraçäo de nisina testada (25 UI mL-1) suficiente para inibir totalmente o desenvolvimento deste último. L. mesenteroides e L. monocytogenes foram controlados somente com a maior concentraçäo de nisina testada (100 UI mL-1). Concentraçöes de 100 UI mL-1 de nisina foram suficientes para conter o desenvolvimento de L. mesenteroides mesmo em salsichas cujas contagens atingiram 1 x 10.000.000 UFC g-1 após o período de incubaçäo quando näo tratadas com nisina. Entretanto, a possível presença de patógenos, como a Listeria monocytogenes, nos faz sugerir a utilizaçäo de nisina em concentraçöes pouco superiores a 100 UL mL-1 para que se obtenha uma margem de segurança. Näo foi detectada diferença significativa (P>0,05) na atividade da nisina para os diferentes tipos de salsicha com nenhum dos microrganismos testados.

Aflatoxin Production in a Meat Mix Model System in the Presence of Pediococcus and Lactobacillus.

The effect on aflatoxin production by Aspergillus parasiticus of eight individual strains of Pediococcus and Lactobacillus was determined. The study was conducted in an axenic cultural system in which irradiated meat was employed in the formulation of a meat medium. The medium composition and incubation temperatures were simulations of Brazilian salami processing conditions. All single cultures of A. parasiticus supported aflatoxin production. More aflatoxin was produced in samples treated by the addition of lactic acid than in nontreated ones. Aflatoxin was not detected when A. parasiticus was grown with lactic acid bacteria, although visible mold growth was observed in all such cultures.