Dynamic of Phenolic Compounds, Antioxidant Activity, and Yield of Rhubarb under Chemical, Organic and Biological Fertilization

Abstract

In recent years, rhubarb is being increasingly cultivated, as it provides early yields when the vegetables supply to market is deficient and shows high levels of both polyphenols content and antioxidant capacity in edible parts. In 2017, we investigated crops of the rhubarb cultivar Victoria to the fifth year of production. Comparisons were performed between three root phase fertilizations—chemical (NPK 16-16-16®), organic (Orgevit®), and biological (Micoseeds MB®)—plus an unfertilized control. The determinations of polyphenols, the antioxidant capacity, and the yield indicators from the stalks (petioles) of rhubarb were made at each out of the 10 harvests carried out. The highest yield (59.16 t·ha−1) was recorded under the chemical fertilization. The total polyphenols content and antioxidant capacity varied widely from 533.86 mg GAE·g−1 d.w. and 136.86 mmol Trolox·g−1 d.w., respectively in the unfertilized control at the last harvest, up to 3966.56 mg GAE·g−1 d.w. and 1953.97 mmol Trolox·g−1 d.w. respectively under the organic fertilization at the four harvest. From the results of our investigation, it can be inferred that the chemical fertilization was the most effective in terms of yield, whereas the sustainable nutritional management based on organic fertilizer supply led to higher antioxidant compounds and activity.

The Use of Compost Increases Bioactive Compounds and Fruit Yield in Calafate Grown in the Central South of Chile

“…Nevertheless, the results obtained in the compost treatments were superior to the control treatment. This has been corroborated in other species, such as strawberries, where the effect of an organic fertilization based on compost increased the contents of anthocyanins, phenolic contents, and antioxidant capacity, and also in the Rhubarb (Rheum rhabarbarum L.) crop, where organic fertilization also improved the levels of polyphenolic content and antioxidant capacity of the fruit [48,51]. In a study conducted by Cojocaru et al, no increase in fruit yield was observed as it was observed in this study (Figure 8) and was probably associated with the low doses of compost (2.4 Ton ha −1 ) used in their study [51], which was associated with the high levels of extraction given by the levels of fruit production.…”

Quality, Bioactive Compounds, Antioxidant Capacity, and Enzymes of Raspberries at Different Maturity Stages, Effects of Organic vs. Conventional Fertilization

“…Organic products are also being promoted as more nutritious and healthier since it is considered that they could have a higher concentration of bioactive compounds; however, to date, the results have been contradictory. While, at the same time, some researchers find that organic fertilization increases bioactive compounds [ 7 , 8 , 9 , 10 ], other researchers find the opposite [ 11 , 12 ]. In the case of raspberry, while Jin et al [ 13 ] showed that organic raspberry fruits present higher values in antioxidant capacity, specific flavonoid content, and activity of antioxidant enzymes, Sablani et al [ 11 ] found no difference between organic and conventional management regarding the total content of anthocyanins, phenolic compounds, and antioxidant capacity.…”

The Effect of the Cultivar and Harvest Term on the Yield and Nutritional Value of Rhubarb Juice

“…Although rhubarb is a well-known vegetable, scientific interest in this plant is a relatively new issue; most of the evidence of its biological activities and therapeutic potential derives from the last 15 years [ 4 ]. It shows high levels of both polyphenol content and antioxidant capacity in edible parts [ 5 ], which are petioles characterized by very high antioxidant properties and rich in many compounds that have a pro-health effect on the human body [ 6 ]. There is a wide variety of rhubarb cultivars that contain bioactive compounds such as flavonoids, anthraquinone, glycosides, tannins, volatile oils, and saponins [ 1 ].…”