title: Evaluation of browning ratio in an image analysis of apple slices at different stages of instant controlled pressure drop-assisted hot-air drying (AD-DIC).
abstract: BACKGROUND
  Computer vision-based image analysis systems are widely used in food processing to evaluate quality changes. They are able to objectively measure the surface colour of various products since, providing some obvious advantages with their objectivity and quantitative capabilities. In this study, a computer vision-based image analysis system was used to investigate the colour changes of apple slices dried by instant controlled pressure drop-assisted hot air drying (AD-DIC).
  
  
  RESULTS
  The CIE L* value and polyphenol oxidase activity in apple slices decreased during the entire drying process, whereas other colour indexes, including CIE a*, b*, ΔE and C* values, increased. The browning ratio calculated by image analysis increased during the drying process, and a sharp increment was observed for the DIC process. The change in 5-hydroxymethylfurfural (5-HMF) and fluorescent compounds (FIC) showed the same trend with browning ratio due to Maillard reaction. Moreover, the concentrations of 5-HMF and FIC both had a good quadratic correlation (R2> 0.998) with the browning ratio.
  
  
  CONCLUSIONS
  Browning ratio was a reliable indicator of 5-HMF and FIC changes in apple slices during drying. The image analysis system could be used to monitor colour changes, 5-HMF and FIC in dehydrated apple slices during the AD-DIC process. © 2016 Society of Chemical Industry.
authors.affiliation: Institute of Food Science and Technology, CAAS, Key Laboratory of Agro-Products Processing, Ministry of Agriculture, Beijing, 100193, China.|Department of Food Science, Shenyang Agricultural University, Shenyang, 110866, China.
authors.forename: Kun
authors.initials: K
authors.lastname: Gao
authors.affiliation: Institute of Food Science and Technology, CAAS, Key Laboratory of Agro-Products Processing, Ministry of Agriculture, Beijing, 100193, China.
authors.forename: Linyan
authors.initials: L
authors.lastname: Zhou
authors.affiliation: Institute of Food Science and Technology, CAAS, Key Laboratory of Agro-Products Processing, Ministry of Agriculture, Beijing, 100193, China.|Department of Food Science, Shenyang Agricultural University, Shenyang, 110866, China.
authors.forename: Jinfeng
authors.initials: J
authors.lastname: Bi
authors.affiliation: Institute of Food Science and Technology, CAAS, Key Laboratory of Agro-Products Processing, Ministry of Agriculture, Beijing, 100193, China.
authors.forename: Jianyong
authors.initials: J
authors.lastname: Yi
authors.affiliation: Institute of Food Science and Technology, CAAS, Key Laboratory of Agro-Products Processing, Ministry of Agriculture, Beijing, 100193, China.
authors.forename: Xinye
authors.initials: X
authors.lastname: Wu
authors.affiliation: Institute of Food Science and Technology, CAAS, Key Laboratory of Agro-Products Processing, Ministry of Agriculture, Beijing, 100193, China.
authors.forename: Mo
authors.initials: M
authors.lastname: Zhou
authors.affiliation: Institute of Food Science and Technology, CAAS, Key Laboratory of Agro-Products Processing, Ministry of Agriculture, Beijing, 100193, China.|Department of Food Science, Shenyang Agricultural University, Shenyang, 110866, China.
authors.forename: Xueyuan
authors.initials: X
authors.lastname: Wang
authors.affiliation: Institute of Food Science and Technology, CAAS, Key Laboratory of Agro-Products Processing, Ministry of Agriculture, Beijing, 100193, China.
authors.forename: Xuan
authors.initials: X
authors.lastname: Liu
mesh_terms: D003116:Color; D005511:Food Handling / Q000295:instrumentation / Q000379:methods*; D005638:Fruit / Q000737:chemistry*; D005662:Furaldehyde / Q000031:analogs & derivatives / Q000032:analysis; D007091:Image Processing, Computer-Assisted; D027845:Malus / Q000737:chemistry*
chemical_list: C008046:5-hydroxymethylfurfural; D005662:Furaldehyde
keywords: 5-hydroxymethylfurfural; Maillard reaction; computer vision-based image analysis; fluorescent compounds; polyphenol oxidase