title: Enhancing the polyphenol content of a red-fleshed Japanese plum (Prunus salicina Lindl.) nectar by incorporating a polyphenol-rich extract from the skins.
abstract: BACKGROUND
  Plum skins are a waste product generated during production of plum juice or pulp. Polyphenols, shown to have various health-promoting properties, can be recovered from this waste product. Red-fleshed plum nectar formulations containing plum skin extract in varying amounts were characterised in terms of intensity of sensory attributes, consumer acceptability, colour, polyphenol content and antioxidant activity. Commercial beverages containing red fruits were used as benchmarks.
  
  
  RESULTS
  The polyphenolic profile of the plum skin extract was similar to that of the pulp, including anthocyanins, flavonols, flavan-3-ols and a phenolic acid. Addition of the extract to plum nectar, which enhanced the colour, polyphenol content and antioxidant capacity, was limited by its negative sensory impact. The formulations were deemed acceptable by consumers, although a decrease in positive sensory attributes (plum flavour, plum aroma and sweetness) and an increase in negative sensory attributes (plant-like flavour, plant-like aroma, acidity and astringency) were observed with increasing skin extract content. The formulations compared favourably with commercial beverages in terms of colour total polyphenol content and antioxidant activity.
  
  
  CONCLUSIONS
  Plum skins were successfully used to enhance the functional status of plum nectar. Use of a functional ingredient from plum skins is, therefore, a feasible value-addition strategy.
authors.affiliation: Post-Harvest and Wine Technology Division, Agricultural Research Council, Stellenbosch, South Africa. dbeerd@arc.agric.za
authors.forename: Dalene
authors.initials: D
authors.lastname: de Beer
authors.forename: Naomi
authors.initials: N
authors.lastname: Steyn
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Joubert
authors.forename: Nina
authors.initials: N
authors.lastname: Muller
mesh_terms: D000143:Acids; D000975:Antioxidants / Q000032:analysis* / Q000494:pharmacology; D001252:Astringents; D001628:Beverages; D003116:Color; D003258:Consumer Behavior; D005638:Fruit / Q000737:chemistry*; D055951:Functional Food; D009812:Odorants; D010936:Plant Extracts / Q000737:chemistry* / Q000494:pharmacology; D028321:Plant Preparations; D059808:Polyphenols / Q000032:analysis* / Q000494:pharmacology; D027861:Prunus / Q000737:chemistry*; D013649:Taste
chemical_list: D000143:Acids; D000975:Antioxidants; D001252:Astringents; D010936:Plant Extracts; D028321:Plant Preparations; D059808:Polyphenols