Fruit production and polyphenol content of salal (Gaultheria shallon Pursh), a potential new fruit for northern maritime regions

Cool growing seasons, high rainfall, wind and reduced sunshine challenge fruit production in northern maritime regions. Salal (Gaultheria shallon Pursh) originates from the Pacific Northwest of North America and our research investigated its fruit production and chemical composition in Orkney, north of mainland Scotland. Materials and methods. Fruit production from a 20-plant row was recorded over 3 seasons and fruits were analysed for total polyphenol, anthocyanin content (TPC and TAC) and antioxidant capacity (FRAP). Results and discussion. Fruiting occurred from August to October. Although 16−18 pickings were required to harvest the entire crop, about 75% was picked over 4 weeks when maximum production occurred. Annual production varied from 0.7 to 2.3 kg m-1 of row, indicating potential yields of 2.7 to 9.1 t ha-1 at 10 years for hedgerows 2.5 m apart. In 2014, average fruit weight, height and diameter ranged from 467 to 680 mg, 9.9 to 10.5 mm and 9.2 to 10.2 mm, respectively. The maximum picking rate was about 1.0 kg h-1 but was constrained by poor synchronisation of fruit ripening. Variations between years in fruit TPC (658−968 mg 100 g-1 fw) were reflected in variations in TAC (121−219 mg 100 g-1 fw) and FRAP (63,048−100,815 ¯M Fe 100 g-1 fw). TPC and TAC values were similar to those for blackcurrant (Ribes nigrum L.) varieties. Conclusion. Salal grew well in Orkney’s maritime environment and fruited reliably. This fruit has potential for novel food and drink, but commercialisation will require improved selections, notably for ease of harvest.