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

Abstract

Since scientific interest in rhubarb from a culinary point of view is a relatively new issue, the aim of this study was to test five edible cultivars of Rheum rhabarbarum L. (‘Poncho’, ‘Canadian Red’, ‘Valentine’, ‘Red Champagne’, and ‘Victoria’) from a specific culinary perspective, i.e., processing into juice. Total yields (t/ha) were established in six harvests during a two-year field experiment. For juice production and subsequent laboratory analysis, rhubarb petioles from two different harvest terms were used (i.e., harvest term A (HTA) and harvest term B (HTB)). Analyses of total sugar, glucose, fructose, total soluble solids (TSS), total acidity, malic acid, and pH level were determined by FT-IR spectrophotometer. Total yields of petioles varied between 28.77 t/ha (‘Canadian Red’) and 45.58 t/ha (‘Red Champagne’) at a density of 11,000 pl/ha. ‘Red Champagne’ significantly (p < 0.05) reached the highest juice yield potential (85%) and the highest values of glucose (9.97 g/L), total soluble solids (4.37 g/L), and total sugars (54.96 g/L).

Varietal Differences in Juice, Pomace and Root Biochemical Characteristics of Four Rhubarb (Rheum rhabarbarum L.) Cultivars

“…Among physicochemical characteristics of rhubarb juice, the density, total dissolved solids (TDS) and monosaccharides content demonstrated the lowest varietal differences ( Table 2 ), which suggests that the values of these parameters are typical of rhubarb varieties grown in the same conditions. Similar low variations in sugar content were recorded by Mezeyova et al [ 32 ] in five rhubarb cultivars. Among the cultivars tested, only cv.…”

“…The data presented in Table 1 indicate that among the rhubarb cultivars tested, cv. Upryamets had the highest stalk yield, which exceeded that of the other cultivars by 1.4–1.8 times ( Table 1 ) and was close to the values of five Slovak cultivars reported by Mezeyova et al [ 32 ].…”

“…Their content and composition are genetically governed; affect plant adaptability; provide antibacterial, antifungal and antiparasitic defense; and are directly related to juice quality [ 50 , 51 ]. The comparison between the results of our research with those of other researchers [ 1 , 13 , 32 , 52 , 53 ] has demonstrated the rather close values of the total organic acids content, within the range of 17–22 g·L −1 . On the other hand, to date, the information about the organic acids composition of rhubarb juice/stalks is rather scant.…”

“…To date, researchers have paid predominant attention to the production of rhubarb juice [ 1 , 32 ]. Indeed, depending on the production technology, its yield may reach up to 80–90%.…”

“…The importance of garden rhubarb for human health and nutrition has promoted various investigations addressed to optimize juice production [ 1 , 32 ], root antioxidant characteristics [ 28 ], pharmaceutical potential [ 25 ] and utilization in the food industry [ 1 ]. On the other hand, the complex characterization and processing of rhubarb plants have not been performed so far, also due to high levels of oxalic acid, which is toxic for human organisms at remarkable concentrations because of calcium oxalate precipitation.…”