Acrylamide content and antioxidant capacity in thermally processed fruit products

Acrylamide as a known processing contaminant was determined in various heat-treated plum products purchased from a local market using LC/ESI-MS-MS. The highest level of acrylamide in the range up to 60 μg/kg was detected in a plum stew known as a "povidla", and in prunes, respectively. These products typically undergo intensive heat treatment that may take from several hours to days. Using a fruit dehydrator in home production of prunes, a low level of acrylamide under LOQ (15 μg/kg) was detected in comparison to most commercial products. Only in one of the prune samples from the market was the acrylamide content near to LOQ. The highest content of acrylamide (46 μg/kg) was detected in the Slovak sample of prune originated in Nitra region. High acrylamide content, in the range from 23 to 45 μg/kg, was observed in prunes from South America. In the rest of analysed heat-treated plum products such as plum juice, plum compote or baby food with plum puree, acrylamide was not detected due to moderate conditions during thermal processing: temperature below 120 °C and a shorter time of thermal exposure. The total phenolic content and antioxidant capacity of prunes were analysed using a UV-VIS-NIR spectrophotometer and an electron paramagnetic resonance (EPR) spectroscopy. Home-prepared prunes were characterized by the highest content of phenolics (4780 mg GAE/kg) and antioxidant capacity (14.6 mmol TEAC/kg). Commercial samples of prunes reached phenolics in the range from 1619 to 3461 mg GAE /kg, and antioxidant capacity was observed between 6.1 and 12.1 mmol TEAC/kg. Antioxidant capacity of prunes strongly correlated with total phenolic content and yellow and red colours measured in a CIELab system. However, no significant correlation between the acrylamide and antioxidative or organoleptic properties of prunes was observed. Moreover, it was noticed that bio production of plums did not demonstrate any positive impact on final acrylamide content or antioxidant capacity in comparison to conventional technology

EFFECTS OF BLANCHING ON GRAPES (VITIS VINIFERA) AND CHANGES DURING STORAGE IN SYRUP

This paper studies the effects of conventional and microwave blanching on grapes that are being processed for storage in syrup. An analysis was made of the blanching effects on macro- and micronutrients, as well as on color and mechanical properties. To test the effectiveness of these blanching treatments, enzymatic residual activity was measured for polyphenol oxidase, peroxidase and pectinmethylesterase. Both blanching treatments reduced enzyme activity in the grapes, especially polyphenol oxidase (99%). Blanching treatments also caused significant decrease in tartaric acid (TA) also as in color and mechanical changes, more marked in conventional-treated samples. As for the effect of storage, microwave treatment supposed a greater stability of TA and total phenols than conventional one, also as a greater antioxidant activity of grapes. From this point of view, microwave treatment of samples immersed in water can be proposed as a good alternative to conventional heating in boiling water for grapes blanching. © 2011 Wiley Periodicals, Inc.The authors thank the Ministerio de Educacion y Ciencia, the Fondo Europeo de Desarrollo Regional and the Conselleria de Educacion y Ciencia for the financial support given throughout the Projects (AGL 2005-05994 and GV04A-394 AGL 2005-05994). The translation of this paper was funded by the Universidad Politecnica de Valencia, Spain.Carranza Concha, J.; Camacho Vidal, MM.; Martínez Navarrete, N. (2012). EFFECTS OF BLANCHING ON GRAPES (VITIS VINIFERA) AND CHANGES DURING STORAGE IN SYRUP. Journal of Food Processing and Preservation. 36(1):11-20. https://doi.org/10.1111/j.1745-4549.2011.00546.xS112036

Molecular Modeling of Peroxidase and Polyphenol Oxidase: Substrate Specificity and Active Site Comparison

Peroxidases (POD) and polyphenol oxidase (PPO) are enzymes that are well known to be involved in the enzymatic browning reaction of fruits and vegetables with different catalytic mechanisms. Both enzymes have some common substrates, but each also has its specific substrates. In our computational study, the amino acid sequence of grape peroxidase (ABX) was used for the construction of models employing homology modeling method based on the X-ray structure of cytosolic ascorbate peroxidase from pea (PDB ID:1APX), whereas the model of grape polyphenol oxidase was obtained directly from the available X-ray structure (PDB ID:2P3X). Molecular docking of common substrates of these two enzymes was subsequently studied. It was found that epicatechin and catechin exhibited high affinity with both enzymes, even though POD and PPO have different binding pockets regarding the size and the key amino acids involved in binding. Predicted binding modes of substrates with both enzymes were also compared. The calculated docking interaction energy of trihydroxybenzoic acid related compounds shows high affinity, suggesting specificity and potential use as common inhibitor to grape ascorbate peroxidase and polyphenol oxidase

Editorial Note for the Special Issue: Perspectives and Challenges in Doctoral Research—Selected Papers from the 10th Edition of the Scientific Conference of the Doctoral Schools from the “Dunărea de Jos”

This editorial note is dedicated to the 10th Scientific Conference which was held on June 2022 in Galati, Romania, and was organized by the Council of Doctoral Schools of the “Dunărea de Jos” University of Galati (SCDS-UDJG) [...

Evolution for First Eigenvalue of LT,f on an Evolving Riemannian Manifold

In this paper, evolution formulas for the first non-zero eigenvalue of the operator LT,f on a weighted closed Riemannian manifold along the Ricci flow as well as along the Yamabe flow are formulated. Some monotonic quantities are also derived for the normalized Ricci flow on Bianchi classes

Some Analysis of the Coefficient-Related Problems for Functions of Bounded Turning Associated with a Symmetric Image Domain

In the last few years, numerous subfamilies of univalent functions, whether directly or indirectly associated with exponential functions, have been introduced and thoroughly investigated. Among these, the families Se*, Ce and Re defined by subordination to ez have been intensively investigated. While the coefficient problem on the class Se* and Ce has been solved in many cases, in this paper, we mainly intend to compute the sharp estimates of some initial coefficients, the Feketo–Szegö inequality, and the sharp bounds of second- and third-order Hankel determinants for functions belonging to the class Re. This work has the potential to significantly enrich and enhance the exploration of univalent functions in conjunction with exponential functions, making the field more comprehensive and robust

On the Study of Starlike Functions Associated with the Generalized Sine Hyperbolic Function

Geometric function theory, a subfield of complex analysis that examines the geometrical characteristics of analytic functions, has seen a sharp increase in research in recent years. In particular, by employing subordination notions, the contributions of different subclasses of analytic functions associated with innovative image domains are of significant interest and are extensively investigated. Since ℜ(1+sinh(z))≯0, it implies that the class Ssinh* introduced in reference third by Kumar et al. is not a subclass of starlike functions. Now, we have introduced a parameter λ with the restriction 0≤λ≤ln(1+2), and by doing that, ℜ(1+sinh(λz))>0. The present research intends to provide a novel subclass of starlike functions in the open unit disk U, denoted as Ssinhλ*, and investigate its geometric nature. For this newly defined subclass, we obtain sharp upper bounds of the coefficients an for n=2,3,4,5. Then, we prove a lemma, in which the largest disk contained in the image domain of q0(z)=1+sinh(λz) and the smallest disk containing q0(U) are investigated. This lemma has a central role in proving our radius problems. We discuss radius problems of various known classes, including S*(β) and K(β) of starlike functions of order β and convex functions of order β. Investigating Ssinhλ* radii for several geometrically known classes and some classes of functions defined as ratios of functions are also part of the present research. The methodology used for finding Ssinhλ* radii of different subclasses is the calculation of that value of the radius r1 for which the image domain of any function belonging to a specified class is contained in the largest disk of this lemma. A new representation of functions in this class, but for a more restricted range of λ, is also obtained