Physicochemical and sensorial properties of grapefruit jams as affected by processing

Jam is an effective and tasty way of preserving fruit. Jam processing procedures as well as storage conditions and duration are important factors for jam quality. Traditional jam processing involves the application of severe thermal treatments that imply undesirable changes in the product quality characteristics such as colour, texture, flavour and nutritional and functional value. In this work, osmotic dehydration (OD) and/or microwave energy (MW) was proven as adequate to obtain jam with the typical characteristics of water content, degree Brix, pH and water activity of jam obtained by conventional thermal heating. The sensory evaluation carried out to compare the product showed that samples submitted to more intense heating treatments (conventional or MW) had significantly higher scores in colour saturation, brightness, grapefruit taste and extensibility than OD or OD+MW ones. As deduced from the obtained results, OD treatment prevents grapefruit colour changes, and mild MW heating contributes to increase the consistency and decrease the extensibility of the obtained jam. In this way, OD+MW jam was preferred by assessors mainly due to its higher consistency. The sample obtained by this procedure was stable during storage.The authors would like to thank the Ministerio de Educacion y Ciencia for the financial support given throughout the Project AGL 2005-05994. The language revision of this paper was funded by the Universidad Politecnica de Valencia, Spain.Igual Ramo, M.; García Martínez, EM.; Camacho Vidal, MM.; Martínez Navarrete, N. (2013). Physicochemical and sensorial properties of grapefruit jams as affected by processing. Food and Bioprocess Technology. 6(1):177-185. https://doi.org/10.1007/s11947-011-0696-2S17718561AENOR (2009). Sensory analysis. Methodology. Paired comparison test. UNE-EN-ISO 5495.AOAC. (2000). 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The Kinetics and Mechanism of the Organo-Iridium-Catalysed Enantioselective Reduction of Imines

The iridium complex of pentamethylcyclopentadiene and (S,S)-1,2-diphenyl-N′-tosylethane- 1,2-diamine is an effective catalyst for the asymmetric transfer hydrogenation of imine substrates under acidic conditions. Using the Ir catalyst and a 5:2 ratio of formic acid: triethylamine as the hydride source for the asymmetric transfer hydrogenation of 1-methyl-3,4- dihydroisoquinoline and its 6,7-dimethoxy substituted derivative, in either acetonitrile or dichloromethane, shows unusual enantiomeric excess (ee) profiles for the product amines. The reactions initially give predominantly the (R) enantiomer of the chiral amine products with >90% ee but which then decreases significantly during the reaction. The decrease in ee is not due to racemisation of the product amine, but because the rate of formation of the (R)- enantiomer follows first-order kinetics whereas that for the (S)-enantiomer is zero-order. This difference in reaction order explains the change in selectivity as the reaction proceeds - the rate formation of the (R)-enantiomer decreases exponentially with time while that for the (S)- enantiomer remains constant. A reaction scheme is proposed which requires rate-limiting hydride transfer from the iridium hydride to the iminium ion for the first-order rate of formation of the (R)-enantiomer amine and rate-limiting dissociation of the product for the zero-order rate of formation of the (S)-enantiomer

New carboalkoxybis(triphenylphosphine)palladium(II) cationic complexes: Synthesis, characterization, reactivity and role in the catalytic hydrocarboalkoxylation of ethene. X-ray structure of trans-[Pd(COOMe)(TsO)(PPh3)2]·2CHCl3

The cationic complexes trans-[Pd(COOR)(H2O)(PPh3)2](TsO) have been synthesised by reacting cis-[Pd(H2O)2(PPh3)2](TsO)2·2H2O with CO in ROH (R = Me and Et), practically under room conditions, or by methathetical exchange of trans-[Pd(COOMe)Cl(PPh3)2] with Ag(TsO) (R = n-Pr, iso-Pr, n-Bu, iso-Bu, sec-Bu). They have been characterised by IR, 1H NMR and 31P NMR spectroscopies. The X-ray investigation of trans-[Pd(COOMe)(TsO)(PPh3)2] reveals that the palladium center is surrounded in a virtually square planar environment realized by two PPh3 trans to each other, the carbon atom of the carbomethoxy ligand and an oxygen atom of the p-toluensulfonate anion, with two crystallization molecules of CHCl3. The Pd–O–S angle, 151.9 (3)°, is very wide, probably due to the interaction of one CHCl3 molecule with the complex inner core. The carbomethoxy derivatives react with R′OH yielding the corresponding R′ carboalkoxy derivative (R′ = Et, n-Pr and iso-Pr); ethene does not insert into the Pd–COOMe bond; decarbomethoxylation occurs when treated with TsOH/H2O in MeOH at 50 °C. All the carboalkoxy are precursors for the catalytic carboalkoxylation of ethene if used in combination of PPh3 and TsOH, better in the presence of some water. Experimental evidences are more in favor of the so-called “hydride” mechanism rather than the “carbomethoxy” mechanism

Experiences of the implementation and operation of hazard analysis critical control points in the food service sector

This study explored experiences of implementation and operation of hazard analysis critical control points (HACCP) in the foodservice sector through in-depth interviews with seven foodservice outlets in the South East of England. Experiences highlighted a number of barriers to the successful implementation and operation of HACCP, and also perceived benefits. Barriers included difficulties identifying hazards, inadequate knowledge, time-related issues relating to monitoring and recording, excessive documentation, convincing staff of the importance of the system, and increased costs. Perceived benefits included protecting the business from otherwise unforeseen problems and providing evidence of 'due diligence'. There was, however, an attitude of compliance, rather than true recognition of the value of the system. © 2004 Elsevier Ltd. All rights reserved

Experiences of the implementation and operation of hazard analysis critical control points in the food service sector

This study explored experiences of implementation and operation of hazard analysis critical control points (HACCP) in the foodservice sector through in-depth interviews with seven foodservice outlets in the South East of England. Experiences highlighted a number of barriers to the successful implementation and operation of HACCP, and also perceived benefits. Barriers included difficulties identifying hazards, inadequate knowledge, time-related issues relating to monitoring and recording, excessive documentation, convincing staff of the importance of the system, and increased costs. Perceived benefits included protecting the business from otherwise unforeseen problems and providing evidence of 'due diligence'. There was, however, an attitude of compliance, rather than true recognition of the value of the system. © 2004 Elsevier Ltd. All rights reserved

Food safety management

In-flight catering is a central part of these strategies at all levels: be they customer satisfaction, marketing, operations or logistics

Food safety management

In-flight catering is a central part of these strategies at all levels: be they customer satisfaction, marketing, operations or logistics