title: Stabilization of red fruit-based smoothies by high-pressure processing. Part A. Effects on microbial growth, enzyme activity, antioxidant capacity and physical stability.
abstract: BACKGROUND
  Non-thermal pasteurization by high-pressure processing (HPP) is increasingly replacing thermal processing (TP) to maintain the properties of fresh fruit products. However, most of the research on HPP-fruit products only partially addresses fruit-pressure interaction, which limits its practical interest. The objective of this study was to assess the use of a mild HPP treatment to stabilize red fruit-based smoothies (microbial, enzymatic, oxidative and physical stability).
  
  
  RESULTS
  HPP (350 MPa/10 °C/5 min) was slightly less effective than TP (85 °C/7 min) in inactivating microbes (mesophilic and psychrophilic bacteria, coliforms, yeasts and moulds) in smoothies kept at 4 °C for up to 28 days. The main limitation of using HPP was its low efficacy in inactivating oxidative (polyphenol oxidase and peroxidase) and hydrolytic (pectin methyl esterase) enzymes. Data on antioxidant status, colour parameters, browning index, transmittance, turbidity and viscosity confirmed that the HPP-smoothies have a greater tendency towards oxidation and clarification, which might lead to undesirable sensory and nutritional changes (see Part B).
  
  
  CONCLUSIONS
  The microbial quality of smoothies was adequately controlled by mild HPP treatment without affecting their physical-chemical characteristics; however, oxidative and hydrolytic enzymes are highly pressure-resistant, which suggests that additional strategies should be used to stabilize smoothies. © 2016 Society of Chemical Industry.
authors.affiliation: Department of Food Science & Technology and Human Nutrition, Faculty of Veterinary Science, University of Murcia, Espinardo, E-30100, Murcia, Spain.
authors.forename: Adriana
authors.initials: A
authors.lastname: Hurtado
authors.affiliation: IRTA-Food Technology Program, Finca Camps i Armet, Monells, E-17121, Girona, Spain.
authors.forename: Maria Dolors
authors.initials: MD
authors.lastname: Guàrdia
authors.affiliation: IRTA-Food Technology Program, Finca Camps i Armet, Monells, E-17121, Girona, Spain.
authors.forename: Pierre
authors.initials: P
authors.lastname: Picouet
authors.affiliation: IRTA-Food Safety Program, Finca Camps i Armet, Monells, E-17121, Girona, Spain.
authors.forename: Anna
authors.initials: A
authors.lastname: Jofré
authors.affiliation: Department of Food Science & Technology and Human Nutrition, Faculty of Veterinary Science, University of Murcia, Espinardo, E-30100, Murcia, Spain.
authors.forename: José María
authors.initials: JM
authors.lastname: Ros
authors.affiliation: Department of Food Science & Technology and Human Nutrition, Faculty of Veterinary Science, University of Murcia, Espinardo, E-30100, Murcia, Spain.
authors.forename: Sancho
authors.initials: S
authors.lastname: Bañón
mesh_terms: D000975:Antioxidants / Q000032:analysis* / Q000737:chemistry; D001628:Beverages / Q000032:analysis* / Q000382:microbiology; D002265:Carboxylic Ester Hydrolases / Q000737:chemistry / Q000378:metabolism; D004795:Enzyme Stability; D005519:Food Preservation; D063427:Food Quality; D061353:Food Storage; D005638:Fruit / Q000737:chemistry* / Q000201:enzymology / Q000382:microbiology; D005658:Fungi / Q000254:growth & development / Q000302:isolation & purification; D006090:Gram-Negative Bacteria / Q000254:growth & development / Q000302:isolation & purification; D006094:Gram-Positive Bacteria / Q000254:growth & development / Q000302:isolation & purification; D006358:Hot Temperature / Q000009:adverse effects; D015416:Maillard Reaction; D050296:Microbial Viability; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000737:chemistry / Q000378:metabolism; D010860:Pigments, Biological / Q000032:analysis / Q000737:chemistry; D014674:Plant Proteins, Dietary / Q000737:chemistry / Q000378:metabolism*; D011312:Pressure / Q000009:adverse effects; D012034:Refrigeration; D013030:Spain; D014783:Viscosity
chemical_list: D000975:Antioxidants; D010860:Pigments, Biological; D014674:Plant Proteins, Dietary; D010088:Oxidoreductases; D002265:Carboxylic Ester Hydrolases; C022323:pectinesterase
keywords: clarification; high pressure; non-thermal pasteurization; oxidation; red fruit; smoothie