Plant oil bioconversion into increase biological activity through lipases derived from wastes

The aim of this study was to show that abundant and inexpensive plant oils can be biotransformed to increase biological activity (antioxidant, antimicrobial and cytotoxicity) through hydrolysis reaction catalysed by lipases. We tested homemade and commercial lipases through the biotransformation of nine different plant oils in forty different combinations. First, the chemical composition of the samples was investigated. Thereafter, biological tests were conducted to assess the antioxidant and antimicrobial activity of the sampled biotransformation products, as well as analyzed their influence on the viability of healthy and cancer cells. Summarising, sunflower, corn and olive oils modified by orange waste-obtained lipases presented the most promising results, reaching up to 90% of antioxidant activity increase and significant growth inhibition of bacteria colonies belonging to genera Escherichia, Listeria, Staphylococcus, Pseudomonas and Salmonella. In addition, those compounds affected human oral squamous carcinoma cells. The bioconversion of plant oils through lipases improves their biological properties and might be an option for biotechnological application.     

Determination of Menbutone in Bovine Milk and Meat Using Micellar Liquid Chromatography: Application to Injectable Dosage Forms

A simple, sensitive, and rapid method was developed for the routine identification and quantification of menbutone in different matrices by micellar liquid chromatography. Separation was performed in less than 4 min using a C₁₈ column with UV detection at 234 nm. A micellar solution composed of 0.12 M sodium dodecyl sulfate, 8 % n-butanol, and 0.3 % triethylamine in 0.02 M phosphoric acid at pH 6.0 was used as the mobile phase. The method was fully validated in accordance with International Conference on Harmonization (ICH) guidelines. The limits of detection and quantitation were 0.95 and 2.86 ng mL^?1, respectively. The method showed good repeatability, linearity, and sensitivity according to the evaluation of the validation parameters. The micellar method was successfully applied for the analysis of menbutone in its commercial injections with a mean % recovery value of 99.73?±?1.634 % and in spiked bovine milk and meat samples with a mean % recovery values in the range of 98.00–100.60 %. High extraction efficiency was obtained without matrix interference in the extraction process and in the subsequent chromatographic determination. No organic solvent was used during the pretreatment step. Hence, this method can be considered as an interesting example for green chemistry.     

Enhancing the rheological,technological, textural and microstructural characteristics of set yoghurt using certain nano-stabilisers

The purpose of this study was to investigate the impact of adding nano-stabilisers on some properties of yoghurt. Carboxymethyl cellulose (CMC), sodium alginate (SA) and kappa-carrageenan (K-C) were used at 0.2%, 0.2% and 0.02% in their original forms and 0.15%, 0.15% and 0.015% in nano-form, respectively. The effects of these additives on yoghurt pH, titratable acidity, viscosity, syneresis, texture, colour, starter culture bacterial count, mould and yeast count, coagulation time and microstructure were studied. The use of nano-stabilisers increased viscosity, hardness and coagulation time; reduced syneresis and Streptococcus thermophilus count; and improved colour. Results indicated that nano-stabilisers improved the rheological and technological characteristics of yoghurt.     

Generalization of a lumped parameters model using fractional derivatives applied to rice hydration

This study presents a generalization of a lumped parameters model through the use of fractional derivatives of arbitrary order. The conventional model has an analytical solution in terms of exponential function. However, when applied to kinetic data on moisture absorption in rice grains, its performance was worse when compared to the proposed generalized model. The results were analyzed for four hydration temperatures. Despite the similarity of the mass transfer coefficients for both models, the proposed generalization provided a statistically significant improvement in prediction of moisture values in relation to time and process temperature.

Practical applications

The model proposed in this paper is applicable in describing the hydration kinetics of rice which is an important step in parboiling process, for instance. The simplicity of the analytical solution of the model and the improvement of its prediction capability makes the presented approach useful to project of equipment intended to process rice.     

Microbiological,physical and chemical characteristics of freshwater prawns (Macrobrachium rosenbergii) in modified‐atmosphere packaging

This study evaluated the influence of packaging atmosphere (air versus 50% N₂/50% CO₂) on microbiological (mesophiles, psychrotrophs), physical (gas measurement) and chemical (pH, total volatile basic nitrogen [TVB‐N], NH₃, H₂S and biogenic amines) parameters in freshwater prawns during storage at 0 ± 1 °C for 240 h. To select the most appropriate packaging, 21 batches of each treatment were analysed. Both the packaging permeability and the combination of gases affected the shelf life, but the modified‐atmosphere packaging (MAP) was more efficient than air packaging, increasing the shelf life by 40 h. The parameters of pH and TVB‐N showed no statistical difference between the two atmosphere conditions all along the storage period. The biogenic amine agmatine showed potential for use as a quality indicator due to the increased concentration during storage. In further studies, this amine can be applied as an indicator for public health issue.