Marina Czerner

Ripening of salted anchovy (Engraulis anchoita): development of lipid oxidation, colour and other sensorial characteristics

BACKGROUND Changes in lipids are in general associated with quality deterioration, though earlier studies in anchovy indicate that the volatile compounds of importance to the characteristic flavour could be generated by lipid oxidation. The aim of the present paper was to study the changes in the fatty acid composition and the lipid oxidation of Engraulis anchoita during ripening and their relationship with the development of the typical sensorial characteristics. RESULTS As a result of ripening, polyunsaturated fatty acids decrease from 4.27 to 2.42 and 2.00 g kg(-1) fatty acids in gutted fish and fillet, respectively. The most affected class of fatty acids was the n-3 fatty acids, especially docosahexaenoic acid. Moreover, saturated fatty acids were the most stable to the process. 2-Thiobarbituric acid reactive substances (TBARS) increased throughout ripening, and the use of fillets instead of gutted fish reduced this value. The a value was the parameter most modified, showing a marked increase which correlates with the acquisition of a uniform pink colour. Sensory analysis did not show development of off-odour or undesirable changes in colour during ripening. CONCLUSION As a result of ripening, the fatty acid profile was modified and an increment of TBARS was observed. However, these changes did not lead to deterioration in the quality of the product.

Bacterial Contribution to Salted Anchovy (Engraulis anchoita Hubbs & Marinni, 1935) Ripening Process

The bacterial populations of the salted anchovy ripening process and its potential role on the development of the typical sensory characteristics of this product were studied. Salted anchovy samples were taken during the ripening process and submitted to microbiological analyses in order to monitor the evolution of bacterial groups. According to the results obtained, the ripening process was dominated by moderate halophilic bacteria. Moreover, many of the isolated strains showed proteolytic, lipolytic, and trimethylamine oxide (TMAO) reductase activities. These activities contribute to the development of the typical flavor of this product and to the increase of total volatile bases observed during ripening.

On the Feasibility of Identifying First Order Ogden Constitutive Parameters of Gelatin Gels from Flat Punch Indentation Tests

The feasibility of extracting First Order Ogden constitutive parameters of gelatin gels from experimental flat punch indentation curves is analyzed. Eight gelatin gel samples of different formulations are evaluated. Identification of constitutive parameters is carried out by an inverse method that combines finite element modeling simulations and numerical optimization. Parameters are compared with those obtained from uniaxial compression. A parametric study of the influence of model parameters on the shape of curves and a sensitivity analysis of parameter re-identification is performed. Accurate extraction of parameters is possible if the domain in which α parameter stands are lower than 2.

Effect of different preservation processes on chemical composition and fatty acid profile of anchovy (Engraulis anchoita)

Abstract The effects of salting–ripening, canning and marinating processes on chemical composition and fatty acid profile of anchovy (Engraulis anchoita) were evaluated (p = 0.01), with emphasis on long-chain polyunsaturated fatty acids. Fresh anchovy showed a high proportion of PUFAs (∼45 g/100 g total lipid) with an eicosapentaenoic (EPA) + docosahexaenoic (DHA) content of 27.08 g/100 g total lipid. The salting–ripening process led to the largest changes in the chemical composition and the fatty acid profile, which resulted in a reduction of ∼70% on the total EPA and DHA contents (g/100 g edible portion). Contrary, canned and marinated anchovy presented a fatty acid profile similar to that of fresh anchovy. The use of vegetable oil as covering liquid led to final products with increased ω-6 PUFAs content. Despite the modifications observed, the total amount of essential EPA and DHA fatty acids provided by these products remained high compared with values reported in literature for other foods.

Wire Cutting Method to Assess Fracture Toughness of Gelatin Gels: Phenomenological Analysis and Limitations of Methodology

In this work the performance of the wire cutting method for determining the fracture toughness, Gc, of gelatin hydrogels is assessed. In this method, wires of different diameters are pushed into a sample while the force and displacement are continuously recorded. The cutting action reaches a steady state, in which fracture propagation, deformation, and friction occur simultaneously. The method implies a linear relationship between the steady-state cutting force per unit sample width and the wire diameter, of which the y-intercept is Gc. Several gel samples differing in gelatin concentration, source (bovine or porcine), solvent (water or water–glycerol mixture), and crosslink type (physical or chemical induced by glutaraldehyde) were tested at different rates. Post-mortem fracture surfaces examined via optical microscopy displayed four different morphologies depending on the gel formulation, cutting rate, and wire diameter: I, striated; II, with one or two oblique straight lines; III, with rhombus-like figures; and IV, with material pull-out. A direct relationship between the developed fracture surface morphology and the method performance existed. One necessary condition for obtaining the linear relationship is a unique fracture surface morphology remaining for all of the wires utilized in the determination. The method is invalid if the fracture surface morphology changes with changing wire diameter, abnormal crack path deflection takes place, or material pull-out occurs as a result of adhesion effects. The applicability of the method seems to be not constrained to physical gels. An appropriate cutting rate and wire diameter have to be selected in order for a unique fracture surface morphology to be achieved. In such cases, reasonable Gc values were obtained from the y-intercept of the best linear fit of experimental data. Gc increased with increasing gelatin concentration, Bloom number, and solvent viscosity. Moreover, Gc was greater when a rhombus-like pattern was induced rather than other morphology due to greater crack path tortuosity.

On the interpretation of textural properties of gels through the mechanics of soft materials

Point your SmartPhone at the code above. If you have a QR code reader the video abstract will appear. Or use: https://youtu.be/GPMazmYB5Ac Background: Himalayan honey, a natural product of wild honey bees found in the Himalayan mountains of Nepal, has been used in medicine for many years. The successful development of nanotechnology and beneficial effects of honey would bring a new opportunity to synthesize hybrid nanomaterials for biomedical applications. Thus, the purpose of this study was to load Himalayan honey onto iron oxide nanoparticles (IO-NPs) and study their antioxidant and antimicrobial activities. Methods: Himalayan honey loaded iron oxide nanoparticles (HHLIO-NPs) were synthesized and X-ray diffraction (XRD) and scanning electron microscope (SEM) analyses were performed for characterization. UV-VIS spectra confirmed the loading of honey onto nanoparticles. The antioxidant activity of these nanoparticles was studied against 1, 1-diphenyl-2picrylhydrazyl (DPPH) radical system. We also tested antimicrobial activity of HHLIO-NPs using well diffusion method towards both Gram-positive and Gram-negative bacterial strains of Staphylococus aureus & Escherichia coli. Results: From XRD analysis, the average particle size was found to be 33–40 nm. The SEM images show needle shape porous structures of HHLIO-NPs compared to free IO-NPs indicating the surfactant-like behaviour of honey. In DPPH radical system, the scavenging activities of Himalayan honey (HH), free IO-NPs and HHLIO-NPs ranged 7.93-35.99%, 11.02-52.02% and 16.10-80.52% respectively, with corresponding IC50 values of 1.36 mg/ mL, 1.09 mg/mL and 0.52 mg/mL. The antimicrobial property of all test samples showed a noteworthy inhibition on both bacterial strains. However, the HH and HHLIO-NPs exhibited strong antibacterial activity against E. coli. Conclusion: This work reveals that the biological activity of HH is enhanced significantly after loading into IO-NPs. Thus, the HHLIO-NPs would be a promising alternative for antioxidant and antimicrobial agents.P residues contamination is one of the major concerns worldwide, which influences the practical and structural integrity of an environment. Their direct and indirect effects on human health cannot be avoided. The purpose of this study was to highlight the traceability of organochlorine pesticide residues on the food chain: feed fatty tissue, meat meat products. All samples were collected from a slaughter house in Cluj County. The fat and meat samples were stored at 18 °C temperature and the feed samples at room temperature. The gas chromatographic method was followed for identification of organochlorine pesticide residues from vegetable and animal food. In the collected samples, the largest weight had DDT and its metabolites (375.9 ng/g fat) and HCH isomers (277.7 ng/g fat) site by chlordane, heptachlor, heptachlor epoxide, as well as endosulfan. Regarding the contents of ∑DDT it can be observed that the largest amount was found in fatty tissue, mainly being bioaccumulated in mesenteric tissue and organs. This may be due to the cumulative effect of DDT and its metabolites in fatty tissues and organs (liver, kidney, heart, and spleen) reported also by Covaci et al. In the case of ∑ HCH was found a preferential accumulation in meat followed by organ, fatty tissue and meat products. Regarding organochlorine pesticide residues traceability, it can be concluded that their presence in feed make them to be presented both in the adipose tissue, organs and muscle tissue, as well as in the meat products. Codification of the samples was as follows: feed samples Fj; fatty tissue samples: fat O, bacon S, caul M; meat samples: pork neck CF, chops CO, leg P; samples of paste composition: paste composition for frankfurters and rosy sausages CFP, paste composition for semi-smoked samples PCS; and meat products samples: frankfurters CW, rosy sausage PZ, salam vară salami SV, smoked sausages CA, trandafir sausages CT, and liverwurst LB.

Monitoring the characteristics of cultivable halophilic microbial community during salted-ripened anchovy (Engraulis anchoita) production

The halophilic microbial community of the salted-ripened anchovy process was studied. Samples from raw materials (salt and fresh anchovies) and from the stages of brining and ripening were collected and analyzed for their bacterial counts at 15 and 20% NaCl. No halophilic colonies were found in fresh anchovy and counts of about 103 CFU/g were determined in salt samples. A fluctuation of bacterial counts during the process was found. At the end of brining, ~104 CFU/g were determined in anchovy samples and this value was reduced to not detectable counts at the beginning of the ripening stage. After one month, counts increased to ~104 CFU/g and remained stable until the end of the process. From each sample, colonies having different morphotypes were isolated and submitted to a macro and microscopic characterization, a study of salt requirement for growth, and biochemical and phenotypic tests. The results were submitted to Univariate, Bivariate and Multiple Correspondence Factorial Analysis (MCFA). A total of 79 colonies were isolated during the salting-ripening anchovy process. Among the isolates, about 40-50% was positive for indole production and lipolytic activity and a 25% showed ability to produce H2S and proteolytic capacity. Proteolytic and lipolytic activities were well balanced along the process and resulted independent from the isolation stage, which is a desirable condition due to the contribution of microbial proteolysis and lipolysis to the development of texture and final aroma, respectively. H2S and indole producers practically were not detected during ripening. This fact is important because indole and H2S are associated with the development of off-flavors and spoilage in salted fish products. MFCA and Cluster Analyses complemented the Bivariate Analyses. The factor map showed proximity between the isolates from salt samples and from ripening. Isolates were statistically clustered in two groups. Cluster 1 grouped non-desirable activities (H2S and indole production) with cultures proceeding from brining whereas Cluster 2 related isolates mainly from salt samples and during ripening with some desirable microbial capacities (Cytochrome oxidase activity and non-H2S and non-indole production). These results would indicate that during the ripening process of salted anchovies, a natural selection of beneficial microorganisms for the development of the typical product sensory attributes occurred.