Light-Emitting Diodes improve yield, quality and inhibitory effects on digestive enzymes of strawberry

Abstract

Strawberries are a widely consumed fruit that are increasingly popular due to the perceived health benefits associated with their consumption. Fruit quality is highly dependent on the growing environment where light is one of the most significant environmental factors influencing plant physiology and metabolism. In the present work we sought to test the hypothesis that manipulation of the light environment in a commercial growing environment would influence fruit yield and quality. Fruit were grown with supplemental light-emitting diodes in the red (623 nm), far-red (727 nm) and blue (470 nm) regions of the spectrum at three different densities. The majority of light treatments resulted in increased fruit yield. All treatments also significantly enhanced contents of anthocyanins and polyphenols. Furthermore fruit exhibited enhanced antioxidant activity. Individual strawberry sugars showed differences depending on sampling date whereas Brix, acidity and ascorbic acid was not affected by the LED lights. Strawberry fruit extracts from all treatments exhibited the capacity to inhibit the digestive enzymes pancreatic lipase and α-amylase activity in vitro, extract from fruit grown under supplemental lighting had a greater inhibitory capacity. These data suggest that strawberry fruit grown in the presence of supplemental light may impart health benefits via enhanced functional compounds and by limiting calorific assimilation. The findings of this study provide the first evidence that the use of light-emitting diodes increase the inhibitory effects of polyphenols on digestive enzymes in strawberry.