Poly(hydroxybutyrate-co-hydroxyvalerate) microspheres loaded with atrazine herbicide: screening of conditions for preparation,physico-chemical characterization,and in vitro release studies

Due to their widespread use in agriculture as well as in urban areas, agricultural chemicals are globally some of the most commonly encountered substances in waters. The objective of this study is to develop (including preparation and characterization) a new modified release system for the herbicide atrazine, employing poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) microspheres. The microspheres were prepared by the emulsification/solvent evaporation method, emulsifying an organic phase (atrazine and PHBV dissolved in chloroform) into an aqueous phase containing polyvinyl alcohol (PVA) as surfactant, under stirring, and then evaporating the solvent. A 2^4-1 fractional factorial design, investigating the influence of four variables at two levels, was performed to obtain formulations with optimized association efficiencies. There was a greater dependence of association efficiency on PVA concentration (negative) and the mass of polymer (positive) with lesser influence of both stirring speed and organic phase volume. The size of the particles was assessed using scanning electron microscopy, which showed that the particles were rough-surfaced spheres. The results obtained are promising, since the formulations presented encapsulation efficiency near 25% and the release kinetics profile of atrazine was altered when it was encapsulated in the microparticles, indicating that these systems may be efficient in reducing the environmental impact caused by the herbicide, hence making it safer to use.     

Phenolics from Winemaking By‐Products Better Decrease VLDL‐Cholesterol and Triacylglycerol Levels than Those of Red Wine in Wistar Rats

Winemaking by‐products account for more than 30% of the grape production, but this inexpensive feedstock has not yet been fully exploited. Accordingly, we evaluated the potential biological activity of winemaking by‐products produced with Syrah grapes in comparison with those of the wine produced using the same grape cultivar. Winemaking by‐products showed higher contents of total anthocyanins, flavonols, stilbenes, and flavanols than red wine as evaluated by HPLC‐DAD‐FD (on a dry weight basis). In contrast, red wine was a better source of phenolic acids. However, the contribution of phenolic acids was minor for both samples. Furthermore, equivalent concentration of winemaking by‐products (100 mg/kg/d) showed greater biological activity by than that of red wine by decreasing the levels of VLDL‐cholesterol and triacylglycerols in Wistar rats. Therefore, this study supports the use of winemaking by‐products as an economical source of bioactive phenolics with potential use in the food and nutraceutical industries.     

Rheological Analysis of Sucrose Solution at High Temperatures Using a Microwave‐Heated Pressurized Capillary Rheometer

Thermal process design, optimization, and deviation require the knowledge of engineering properties of food, such as rheological behavior, which is highly dependent on temperature. If a process is calculated based on the parameters obtained by extrapolation, it might lead to over‐ or underprocessing. The long time required for the product to reach the desired temperature, which is usual in many rheometers, may induce unexpected changes on the product. Model solutions are often used in engineering projects in order to simulate characteristics of real products. Thus, the objective of this study was to obtain rheological data of sucrose model solution at the actual high UHT (ultra‐high temperature) process temperatures using a pressurized capillary rheometer, heated by a microwave system. The results provide the rheological behavior of the sucrose solutions and show that there is no deviation of the linearity of the Arrhenius plot above 100 °C for this product. This work was useful to illustrate the use of the applied methodology and to validate the newly built microwave‐heated capillary rheometer. The data obtained confirm the stability of nonsaturated sucrose solution when treated above 100 °C and presents an important contribution to the literature database, since sucrose solutions are used as models for many table syrups, such as maple and sorghum syrups.     

Antioxidant Extracts from Acorns (Quercus ilex L.) Effectively Protect Ready‐to‐Eat (RTE) Chicken Patties Irrespective of Packaging Atmosphere

This study evaluated the impact of a phenolic‐rich acorn extract (200 ppm gallic acid equivalents) and the concentration of oxygen in the packaging system (low‐oxygen modified atmosphere; 5% vs. normal‐oxygen; 21%) on lipid and protein oxidation and consumers acceptance of the ready‐to‐eat chicken patties. Samples were subjected to cooking (electric oven, 170 °C/16 min), cold storage (14 d at 4 °C), and reheating (microwave, 600 mW/1 min). Samples treated with acorn extract kept thiobarbituric acid‐reactive substances numbers and lipid‐derived volatiles at basal levels throughout the whole processing irrespective of the oxygen concentration in the packaging atmosphere. Consistently, treated patties had lower protein carbonyls than control ones. The acorn extract also controlled color and texture deterioration during chilled storage and reheating and improved the color and odor acceptance of the products. Formulating with acorn extract is a feasible strategy to inhibit the oxidation‐driven changes and preserve the quality of reheated samples as if there were freshly cooked. Compared to the effect of the antioxidant extract, the concentration of oxygen in the packaging system was negligible in terms of quality preservation.     

Role of protein oxidation in the nutritional loss and texture changes in ready‐to‐eat chicken patties

The oxidative damage to proteins during processing of ready‐to‐eat chicken patties and its impact on the nutritional value and texture properties of the product were assessed. The effect of cooking techniques (boiling, roasting and grilling) and microwave reheating (600 mW per 1 min) after 7 and 14 days of cold storage (+4 °C) were studied. Cooking methods had an effect (P < 0.05) on most protein oxidation parameters, including protein depletion of tryptophan, thiols, protein carbonylation and formation of cross‐links. Overall, the succeeding chilled storage led to an aggravation of the oxidative damage which occurred along with hardness increase and impaired digestibility. Microwave reheating had contradictory effects on protein oxidation parameters. An increase in protein carbonylation occurred along with a cleavage of disulphide bonds that would explain a decrease in hardness. This study illustrates to which extent the oxidative damage to meat proteins affects protein quality and nutritional value of a severely processed meat product. The impact of assorted cooked procedures on these events is also discussed.     

Aroma profile and consumer liking of salted and dried chicken meat: Effects of desalting and cooking methods

Twenty-four dried and salted broiler breasts, a chicken charqui–like muscle food, were submitted to desalting in cold water and different cooking methods (grilling, roasting, frying with olive oil, and sous-vide cooking). Samples were assessed by levels of thiobarbituric acid reactive substances, volatile compounds, and odor-liking analysis. Desalted and sous-vide cooked samples presented the highest levels of thiobarbituric acid reactive substances and volatile compounds derived from lipid oxidation. Grilling, roasting, and frying promoted an increase of Maillard-derived volatiles in dried salted broiler meat. This difference in aromatic profile led to a high odor acceptability of samples submitted to more intense thermal treatments such as grilling, roasting, and frying. In contrast, prolonged cooking (sous-vide technique) and desalting in cold water led to a marked decline in consumers’ liking due the rise in volatile compounds derived from lipid oxidation. In conclusion, based on the results, it seemed to be reasonable to hypothesize that dried and salted broiler meat submitted to high temperatures during cooking (≈180–200°C) tended to generate high Maillard-derived volatiles, while long cooking times led to a great thermal degradation/oxidation of lipids, which generates high content of lipid-derived volatile components.