Polyphenolic content and antioxidant capacity in fruits of plum (prunus domestica l.) Cultivars "valjevka" and "mildora" as influenced by air drying

Polyphenolic content and antioxidant capacity of freshly harvested plums cvs. "Valjevka" and "Mildora," and changes caused by drying were analyzed. Plum drying at 90C resulted in significant changes in anthocyanins, flavonoids and phenolics content, and antioxidant capacity in both cultivars examined. Statistical analysis showed that antioxidant capacity of both fresh plums and prunes of "Valjevka" and "Mildora" is strongly influenced by the phenolic constituents of the fruit. The major phenolic compound in fresh plums and prunes is neochlorogenic acid, followed by caffeic acid and chlorogenic acid. After drying, a significant decrease in neochlorogenic acid and an increase in caffeic acid was observed, while chlorogenic acid content decreased in prunes of "Valjevka," and increased in prunes of "Mildora." Rutin and protocatechuic acid contents were slightly decreased after drying, while gallic acid content was dramatically increased. A complete degradation of cyanidin was induced by drying

Evolution of mechanical and optical properties of french fries obtained by hot air-frying

The aim of this study was to analyse the influence of frying technique (air-frying and deep oil-frying) and type of pre-treatment (freezing and blanching) on the evolution of mechanical and optical properties of French fries. The results showed that the chromatic parameters, a* and b*, experimented an increase regardless of the frying method. The increase in a* was significantly higher in deep-oil frying as a result of Maillard's reactions. The texture analysis reported a first stage of initial softening related to starch gelatinization followed by a second stage where the maximum force increased due to the gradual formation of a crust, both stages being faster in deep-oil frying. Pre-frozen potatoes presented the highest value of maximum force parameter independent of the type of fryingAuthors would like to thank to the Universitat Politecnica de Valencia (PAID-06-09-2876) for the financial support given to this investigation.Heredia Gutiérrez, AB.; Castelló Gómez, ML.; Argüelles Foix, AL.; Andrés Grau, AM. (2014). Evolution of mechanical and optical properties of french fries obtained by hot air-frying. LWT - Food Science and Technology. 57(2):755-760. https://doi.org/10.1016/j.lwt.2014.02.038S75576057

Risks for public health related to the presence of furan and methylfurans in food

EFSA wishes to thank the hearing experts: Diana Doell and Ruud Woutersen and EFSA staff member: José Cortinas Abrahantes for the support provided to this scientific output. The CONTAM Panel acknowledges all European competent institutions and other stakeholders that provided occurrence data on furan and methylfurans in food, and supported the data collection for the Comprehensive European Food Consumption Database. Adopted: 20 September 2017Peer reviewedPublisher PD

Acrylamide-forming potential of potatoes grown at different locations, and the ratio of free asparagine to reducing sugars at which free asparagine becomes a limiting factor for acrylamide formation

Acrylamide is produced from free asparagine and reducing sugars during high-temperature cooking and food processing, and potato products are major contributors to dietary acrylamide intake. The present study analysed twenty varieties of potatoes grown at two sites (Doncaster and Woburn) in the United Kingdom to assess the effect of location of cultivation on acrylamide-forming potential. Analysis of variance revealed a full site by variety nested within type (French fry, boiling and crisping) by storage interaction for acrylamide (p < 0.003, F-test), reducing sugars and total sugars (p < 0.001, F-test). There was much greater free asparagine in potatoes grown at the Doncaster site compared with the Woburn site. Modelling of the relationship between the ratio of free asparagine to reducing sugars and the levels of acrylamide identified a value of 2.257 ± 0.149 as the tipping point in the ratio below which free asparagine concentration could affect acrylamide formation

Effects of nitrogen and sulfur fertilization on free amino acids, sugars, and acrylamide-forming potential in potato

Nitrogen (N) fertilizer is used routinely in potato (Solanum tuberosum) cultivation to maximize yield. However, it also affects sugar and free amino acid concentrations in potato tubers, and this has potential implications for food quality and safety because free amino acids and reducing sugars participate in the Maillard reaction during high-temperature cooking and processing. This results in the formation of color, aroma, and flavor compounds, but also some undesirable contaminants, including acrylamide, which forms when the amino acid that participates in the final stages of the reaction is asparagine. Another mineral, sulfur (S), also has profound effects on tuber composition. In this study, 13 varieties of potato were grown in a field trial in 2010 and treated with different combinations of N and S. Potatoes were analyzed immediately after harvest to show the effect of N and S fertilization on concentrations of free asparagine, other free amino acids, sugars, and acrylamide-forming potential. The study showed that N application can affect acrylamide-forming potential in potatoes but that the effect is type- (French fry, chipping, and boiling) and variety-dependent, with most varieties showing an increase in acrylamide formation in response to increased N but two showing a decrease. S application reduced glucose concentrations and mitigated the effect of high N application on the acrylamide-forming potential of some of the French fry-type potatoes

Effects of water availability on free amino acids, sugars, and acrylamide-forming potential in potato

Irrigation is used frequently in potato cultivation to maximize yield, but water availability may also affect the composition of the crop, with implications for processing properties and food safety. Five varieties of potatoes, including drought-tolerant and -sensitive types, which had been grown with and without irrigation, were analyzed to show the effect of water supply on concentrations of free asparagine, other free amino acids, and sugars and on the acrylamide-forming potential of the tubers. Two varieties were also analyzed under more severe drought stress in a glasshouse. Water availability had profound effects on tuber free amino acid and sugar concentrations, and it was concluded that potato farmers should irrigate only if necessary to maintain the health and yield of the crop, because irrigation may increase the acrylamide-forming potential of potatoes. Even mild drought stress caused significant changes in composition, but these differed from those caused by more extreme drought stress. Free proline concentration, for example, increased in the field-grown potatoes of one variety from 7.02 mmol/kg with irrigation to 104.58 mmol/kg without irrigation, whereas free asparagine concentration was not affected significantly in the field but almost doubled from 132.03 to 242.26 mmol/kg in response to more severe drought stress in the glasshouse. Furthermore, the different genotypes were affected in dissimilar fashion by the same treatment, indicating that there is no single, unifying potato tuber drought stress response