Evaluating growth models of Pseudomonas spp. in seasoned prepared chicken stored at different temperatures by the principal component analysis (PCA)

Quality and Microbiological Safety of Poultry Meat Marinated with the Use of Apple and Lemon Juice

The aim of the study was to evaluate the use of apple juice for the marinating of poultry meat and its effect on the technological as well as sensory characteristics and microbiological safety of the raw product after heat treatment. Broiler chicken breast muscles were marinated for 12 h in apple juice (n = 30), a mixture of apple and lemon juice (n = 30) and compared with those in lemon juice (n = 30). The control group (n = 30) consisted of unmarinated breast muscles. Following the evaluation of the technological parameters (pH, L*, a*, b* colour, cutting force, cooking losses) quantitative and qualitative microbiological evaluations were performed on the raw and roasted products. The microbiological parameters were determined as total Mesophilic aerobic microorganisms, Enterobacteriaceae family, and Pseudomonas count. The bacterial identification was performed using a matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry. The marinating resulted in lower pH value, but increased tenderness of raw and roasted products. Marinating chicken meat in both apple and lemon juices, including their mixtures and in the control sample, resulted in increased yellow saturation (b*). The highest flavour desirability and overall desirability were obtained in products marinated using a mixture of apple and lemon juice, while the most desirable aroma was obtained from products marinated with apple juice. A significant antimicrobial effect was observed in marinated meat products compared to unmarinated, irrespective of the type of marinade used. The lowest microbial reduction was observed in the roasted products. Apple juice can be used as a meat marinade because it promotes interesting sensory properties and improves the microbiological stability of poultry meat while maintaining the product's good technological characteristics. It makes a good combination with the addition of lemon juice.

Determination of monosaccharides in Lycium barbarum fruit polysaccharide by an efficient UHPLC-QTRAP-MS/MS method

INTRODUCTION

Pre-column derivatisation using 1-phenyl-3-methyl-5-pyrazolone (PMP) is a common method for monosaccharide determination. Herein, a specific ultra-high-performance liquid chromatography quadrupole trap tandem mass spectrometry (UHPLC-QTRAP-MS/MS) method was developed and used for the determination of monosaccharide composition of Lycium barbarum polysaccharide (LBP).

OBJECTIVE

Exploration of a new efficient method for monosaccharide determination.

METHODS

In our study, hydrochloric acid was used to hydrolyse the polysaccharide obtained from L. barbarum fruits. Principal component analysis (PCA) and technique for order of preference by similarity to ideal solution (TOPSIS) analysis were used for comprehensive evaluation of the samples. The results showed that LBP was composed of seven monosaccharides: galactose, arabinose, mannose, rhamnose, xylose, ribose, and glucose. The linear relationship of the seven monosaccharides was optimum within a certain concentration range. Quantitative recoveries of the seven monosaccharides from the samples ranged from 94.76% to 102.11%.

RESULTS

A rapid quantitative detection method was established, in which the hydrolysis time was reduced from 12 h to 2 h. By using LBP as one of the indexes to evaluate the quality of L. barbarum, L. barbarum from Zhongning County, Ningxia Province, was identified as having the best quality among the varieties tested.

CONCLUSION

The UHPLC-QTRAP-MS/MS pre-column derivatisation method used in this study was simple, accurate, and sensitive, with good repeatability, and can be used for quality evaluation and origin distinction of L. barbarum and other medicinal plants.

Use of modified Richards model to predict isothermal and non-isothermal microbial growth

Mathematical models are often used to predict microbial growth in food products. An important class of these models involves the adaptation of classical sigmoid functions, such as the Gompertz and logistic functions. This study aimed to validate the use of the modified Richards model in various situations, which have not previously been tested. The model was obtained through solving a system of two differential equations and could be applied to both isothermal and non-isothermal environments. To test and validate this model, we used published datasets containing data for the growth of Pseudomonas spp. in fish products. The results obtained after fitting the model showed that it could be effectively used to describe and predict the Pseudomonas growth curves under various temperature regimens. However, the influence of the shape parameter on the growth curve is an issue that needs further evaluation.

Effect of different marinating conditions on the evolution of spoilage microbiota and metabolomic profile of chicken breast fillets

Five different marinades were prepared containing lemon juice, apple cider vinegar, pomegranate juice and combinations of them. Three different temperatures (4, 10, and 20 °C) and five marinating time intervals (1, 3, 6, and 9 h) were tested. Microbial, physicochemical as well as sensory analyses were performed to assess marination. Noticeable microbial reductions and satisfactory sensory results were observed only in samples treated for short time (1 and 3 h). The marinade in which pomegranate and lemon juices were combined caused a decrease in microbial counts and led to desirable sensory attributes. Each of the marinades was characterized by a distinguishable organic acid profile, while the discrimination of the samples, based on organic acid concentration, between low (1 and 3) and high (6 and 9) marinating time was feasible. It can be concluded that marinating time affected the indigenous microbiota and the sensory characteristics of chicken meat while pomegranate could be a promising marinating ingredient from a microbiological and physicochemical perspective.

Physical Properties and Volatile Composition Changes of Cooked Sausages Stuffed in a New Casing Formulation Based in Surfactants and Lactic Acid During Long-Term Storage

The objective of this research was to investigate the effects of different modified casings and storage time on the quality attributes of cooked sausages using principal component analysis (PCA) and discriminant analysis. The effects of modifying different casing treatments on sausages' color (L* , a* , b* ), pH, and texture (hardness, springiness, cohesion, gumminess, chewiness) after 36-d storage were estimated by PCA. According to the PCA, lightness at day 36 was correlated to sample stuffed in casing with treatment 2 (T2; soy lecithin concentration: 1:27.5, soy oil concentration: 1.25%, lactic acid concentration: 19.5 mL/kg NaCl [solid], residence time: 75 min). T2 sample can be distinguished from control sample at days 1, 8, 15, and 36 according to electronic nose system. DA was performed to determine possible different sample groups according to selected variables. Results showed that chewiness was the best discriminator for differentiating sausages stored for 15 d from other days. Chewiness and gumminess were able to discriminate sausages stuffed in casing with T2 from control sample. The relationships between modified concentrations and quality attributes of cooked sausages after 36-d storage were also established.

Predicting the growth situation of Pseudomonas aeruginosa on agar plates and meat stuffs using gas sensors

A rapid method of predicting the growing situation of Pseudomonas aeruginosa is presented. Gas sensors were used to acquire volatile compounds generated by P. aeruginosa on agar plates and meat stuffs. Then, optimal sensors were selected to simulate P. aeruginosa growth using modified Logistic and Gompertz equations by odor changes. The results showed that the responses of S₈ or S₁₀ yielded high coefficients of determination (R²) of 0.89-0.99 and low root mean square errors (RMSE) of 0.06-0.17 for P. aeruginosa growth, fitting the models on the agar plate. The responses of S₉, S₄ and the first principal component of 10 sensors fit well with the growth of P. aeruginosa inoculated in meat stored at 4 °C and 20 °C, with R² of 0.73-0.96 and RMSE of 0.25-1.38. The correlation coefficients between the fitting models, as measured by electronic nose responses, and the colony counts of P. aeruginosa were high, ranging from 0.882 to 0.996 for both plate and meat samples. Also, gas chromatography-mass spectrometry results indicated the presence of specific volatiles of P. aeruginosa on agar plates. This work demonstrated an acceptable feasibility of using gas sensors-a rapid, easy and nondestructive method for predicting P. aeruginosa growth.