title: Colour, phenolic content and antioxidant capacity of some fruits dehydrated by a combination of different methods.
abstract: The objective of this study was to improve product quality of dehydrated fruits (apple, pear, papaya, mango) using combined drying techniques. This involved investigation of bioactivity, colour, and sensory assessment on colour of the dried products as well as the retention of the bio-active ingredients. The attributes of quality were compared in regard to the quality of dehydrated samples obtained from continuous heat pump (HP) drying technique. It was found that for apple, pear and mango the total colour change (ΔE) of samples dried using continuous heat pump (HP) or heat pump vacuum-microwave (HP/VM) methods was lower than of samples dried by other combined methods. However, for papaya, the lowest colour change exhibited by samples dried using hot air-cold air (HHC) method and the highest colour change was found for heat pump (HP) dehydrated samples. Sensory evaluation revealed that dehydrated pear with higher total colour change (ΔE) is more desirable because of its golden yellow appearance. In most cases the highest phenol content was found from fruits dried by HP/VM method. Judging from the quality findings on two important areas namely colour and bioactivity, it was found that combined drying method consisted of HP pre-drying followed by VM finish drying gave the best results for most dehydrated fruits studied in this work as the fruits contain first group of polyphenol compounds, which preferably requires low temperature followed by rapid drying strategy.
authors.affiliation: School of Engineering, Taylor's University, Lakeside Campus, No 1, Jalan Taylor's, 47500 Subang Jaya, Selangor, Malaysia.
authors.forename: Chien Hwa
authors.initials: CH
authors.lastname: Chong
authors.forename: Chung Lim
authors.initials: CL
authors.lastname: Law
authors.forename: Adam
authors.initials: A
authors.lastname: Figiel
authors.forename: Aneta
authors.initials: A
authors.lastname: Wojdyło
authors.forename: Maciej
authors.initials: M
authors.lastname: Oziembłowski
mesh_terms: D000975:Antioxidants / Q000737:chemistry*; D029441:Carica / Q000737:chemistry; D003116:Color; D003890:Desiccation / Q000379:methods*; D005511:Food Handling / Q000379:methods*; D005638:Fruit / Q000737:chemistry*; D006358:Hot Temperature; D006801:Humans; D027845:Malus / Q000737:chemistry; D031022:Mangifera / Q000737:chemistry; D010636:Phenols / Q000032:analysis*; D059808:Polyphenols / Q000032:analysis; D031989:Pyrus / Q000737:chemistry; D013649:Taste
chemical_list: D000975:Antioxidants; D010636:Phenols; D059808:Polyphenols
keywords: Antioxidant activity; Apple, pear, papaya, mango; Bioactivity; Combined drying techniques; Polyphenols; Product quality; Sensory assessment