title: Effect of cold storage on total phenolics content, antioxidant activity and vitamin C level of selected potato clones.
abstract: BACKGROUND
  Twelve Colorado-grown specialty potato clones were evaluated for total phenolic content, antioxidant activity and ascorbic acid content at harvest and after 2, 4, 6 and 7 months cold storage at 4 °C. Potato clones were categorized as pigmented ('CO97226-2R/R', 'CO99364-3R/R', 'CO97215-2P/P', 'CO97216-3P/P', 'CO97227-2P/P', 'CO97222-1R/R', 'Purple Majesty', 'Mountain Rose' and 'All Blue'), yellow ('Yukon Gold') and white fleshed ('Russet Nugget', 'Russet Burbank'). Folin-Ciocalteu reagent was used to estimate total phenolic content, and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS(•+) ) and 2,2-diphenyl-1-picrylhydrazyl (DPPH(•) ) radical scavenging assays were used to estimate antioxidant capacity.
  
  
  RESULTS
  Pigmented potato genotypes had significantly higher total phenolic content and antioxidant activity at all data points than yellow- and white-fleshed cultivars. Vitamin C content was higher in 'Yukon Gold' than in the other clones. The highest level of vitamin C in all clones was at harvest and after 2 months in cold storage. Vitamin C content in all potato clones dropped rapidly with longer intervals of cold storage. Although total phenolic content and antioxidant activity fluctuated during cold storage, after 7 months of cold storage their levels were slightly higher than at harvest. Total phenolic content was better correlated with Trolox equivalent antioxidant capacity (TEAC)/ABTS(•+) than the TEAC/DPPH(•) radical scavenging assay.
  
  
  CONCLUSIONS
  Pigmented potato clones had significantly higher total phenolic content and antioxidant activity, while the yellow-fleshed potato cultivar 'Yukon Gold' had significantly higher vitamin C content. Vitamin C content decreased in all potato clones during cold storage, while total phenolics increased in pigmented clones.
authors: Tübitak, Marmara Research Center, Genetic Engineering and Biotechnology Institute, Gebze, Kocaeli, Turkey. oktay.kulen@tubitak.gov.tr
authors: Oktay
authors: O
authors: Külen
authors: Cecil
authors: C
authors: Stushnoff
authors: David G
authors: DG
authors: Holm
mesh_terms: D000975:Antioxidants / Q000378:metabolism* / Q000494:pharmacology; D001205:Ascorbic Acid / Q000378:metabolism*; D052160:Benzothiazoles / Q000378:metabolism; D001713:Biphenyl Compounds / Q000378:metabolism; D003080:Cold Temperature; D004032:Diet; D061353:Food Storage / Q000379:methods*; D006801:Humans; D010636:Phenols / Q000378:metabolism*; D010851:Picrates / Q000378:metabolism; D010860:Pigments, Biological; D035281:Plant Tubers / Q000378:metabolism*; D011198:Solanum tuberosum / Q000145:classification / Q000378:metabolism*; D013045:Species Specificity; D013451:Sulfonic Acids / Q000378:metabolism
chemical_list: D000975:Antioxidants; D052160:Benzothiazoles; D001713:Biphenyl Compounds; D010636:Phenols; D010851:Picrates; D010860:Pigments, Biological; D013451:Sulfonic Acids; C002502:2,2'-azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid; C004931:1,1-diphenyl-2-picrylhydrazyl; D001205:Ascorbic Acid