title: Microwave flow and conventional heating effects on the physicochemical properties, bioactive compounds and enzymatic activity of tomato puree.
abstract: BACKGROUND
  Thermal processing causes a number of undesirable changes in physicochemical and bioactive properties of tomato products. Microwave (MW) technology is an emergent thermal industrial process that offers a rapid and uniform heating, high energy efficiency and high overall quality of the final product. The main quality changes of tomato puree after pasteurization at 96 ± 2 °C for 35 s, provided by a semi-industrial continuous microwave oven (MWP) under different doses (low power/long time to high power/short time) or by conventional method (CP) were studied.
  
  
  RESULTS
  All heat treatments reduced colour quality, total antioxidant capacity and vitamin C, with a greater reduction in CP than in MWP. On the other hand, use of an MWP, in particular high power/short time (1900 W/180 s, 2700 W/160 s and 3150 W/150 s) enhanced the viscosity and lycopene extraction and decreased the enzyme residual activity better than with CP samples. For tomato puree, polygalacturonase was the more thermo-resistant enzyme, and could be used as an indicator of pasteurization efficiency.
  
  
  CONCLUSIONS
  MWP was an excellent pasteurization technique that provided tomato puree with improved nutritional quality, reducing process times compared to the standard pasteurization process. © 2016 Society of Chemical Industry.
authors.affiliation: College of Agriculture and Natural Resources, University of Tehran, Iran.|Postharvest and Refrigeration Group, Universidad Politécnica de Cartagena (UPCT), 30203 Cartagena, Murcia, Spain.|Institute of Plant Biotechnology, UPCT, 30202 Cartagena, Murcia, Spain.
authors.forename: Mitra
authors.initials: M
authors.lastname: Arjmandi
authors.affiliation: Institute of Plant Biotechnology, UPCT, 30202 Cartagena, Murcia, Spain.
authors.forename: Mariano
authors.initials: M
authors.lastname: Otón
authors.affiliation: Postharvest and Refrigeration Group, Universidad Politécnica de Cartagena (UPCT), 30203 Cartagena, Murcia, Spain.|Institute of Plant Biotechnology, UPCT, 30202 Cartagena, Murcia, Spain.
authors.forename: Francisco
authors.initials: F
authors.lastname: Artés
authors.affiliation: Postharvest and Refrigeration Group, Universidad Politécnica de Cartagena (UPCT), 30203 Cartagena, Murcia, Spain.|Institute of Plant Biotechnology, UPCT, 30202 Cartagena, Murcia, Spain.
authors.forename: Francisco
authors.initials: F
authors.lastname: Artés-Hernández
authors.affiliation: Institute of Plant Biotechnology, UPCT, 30202 Cartagena, Murcia, Spain.
authors.forename: Perla A
authors.initials: PA
authors.lastname: Gómez
authors.affiliation: Postharvest and Refrigeration Group, Universidad Politécnica de Cartagena (UPCT), 30203 Cartagena, Murcia, Spain.|Institute of Plant Biotechnology, UPCT, 30202 Cartagena, Murcia, Spain.
authors.forename: Encarna
authors.initials: E
authors.lastname: Aguayo
mesh_terms: D000975:Antioxidants / Q000032:analysis / Q000528:radiation effects; D001205:Ascorbic Acid / Q000032:analysis / Q000528:radiation effects; D002265:Carboxylic Ester Hydrolases / Q000737:chemistry / Q000378:metabolism* / Q000528:radiation effects; D002338:Carotenoids / Q000032:analysis / Q000528:radiation effects; D055598:Chemical Phenomena; D004307:Dose-Response Relationship, Radiation; D004795:Enzyme Stability / Q000528:radiation effects; D005511:Food Handling; D005514:Food Irradiation / Q000009:adverse effects; D063427:Food Quality; D005638:Fruit / Q000737:chemistry* / Q000201:enzymology / Q000528:radiation effects; D006358:Hot Temperature / Q000009:adverse effects; D006801:Humans; D000077276:Lycopene; D018551:Solanum lycopersicum / Q000737:chemistry* / Q000201:enzymology / Q000528:radiation effects; D055595:Mechanical Phenomena; D008872:Microwaves / Q000009:adverse effects; D009753:Nutritive Value; D061352:Pasteurization / Q000379:methods; D010860:Pigments, Biological / Q000032:analysis / Q000528:radiation effects; D010940:Plant Proteins / Q000737:chemistry / Q000378:metabolism* / Q000528:radiation effects; D011096:Polygalacturonase / Q000737:chemistry / Q000378:metabolism* / Q000528:radiation effects; D014783:Viscosity / Q000528:radiation effects
chemical_list: D000975:Antioxidants; D010860:Pigments, Biological; D010940:Plant Proteins; D002338:Carotenoids; D002265:Carboxylic Ester Hydrolases; C022323:pectinesterase; D011096:Polygalacturonase; D001205:Ascorbic Acid; D000077276:Lycopene
keywords: carotenoids; smoothie; thermal treatment; viscosity; vitamin C