Effects of red raspberry polyphenols and metabolites on biomarkers of inflammation and insulin resistance in type 2 diabetes: A pilot study

Berry fruits are rich in polyphenolic compounds (PCs) and may promote health benefits. Anthocyanin (ACNs) concentrations of red raspberry (RR)(Rubus idaeus) extracts were 887.6 ± 262.8 μg/g consisting mainly of...

Effect of Issatchenkia terricola WJL-G4 on Deacidification Characteristics and Antioxidant Activities of Red Raspberry Wine Processing

Our previous study isolated a novel Issatchenkia terricola WJL-G4, which exhibited a potent capability of reducing citric acid. In the current study, I. terricola WJL-G4 was applied to decrease the content of citric acid in red raspberry juice, followed by the red raspberry wine preparation by Saccharomyces cerevisiae fermentation, aiming to investigate the influence of I. terricola WJL-G4 on the physicochemical properties, organic acids, phenolic compounds and antioxidant activities during red raspberry wine processing. The results showed that after being treated with I. terricola WJL-G4, the citric acid contents in red raspberry juice decreased from 19.14 ± 0.09 to 6.62 ± 0.14 g/L, which was further declined to 5.59 ± 0.22 g/L after S. cerevisiae fermentation. Parameters related to CIELab color space, including L*, a*, b*, h°, and ∆E* exhibited the highest levels in samples after I. terricola WJL-G4 fermentation. Compared to the red raspberry wine pretreated without deacidification (RJO-SC), wine pretreated by I. terricola WJL-G4 (RJIT-SC) exhibited significantly decreased contents of gallic acid, cryptochlorogenic acid, and arbutin, while significantly increased contents of caffeic acid, sinapic acid, raspberry ketone, quercitrin, quercetin, baicalein, and rutin. Furthermore, the antioxidant activities including DPPH· and ABTS+· radical scavenging were enhanced in RJIT-SC group as compared to RJO-SC. This work revealed that I. terricola WJL-G4 had a great potential in red raspberry wine fermentation.

Rubus idaeus L. fruit nutrients are affected by different growing technologies

The biochemical compounds of red raspberry (Rubus idaeus L.) fruits cultivated with conventional growing technology and on a nutrient substrate were studied during 2019–2020 at the Federal Horticultural Research Center for Breeding, Agrotechnology and Nursery, Moscow, Russia. The antioxidant activity, phenolic compounds, and ash constituents of the fruits and the metabolites of the alcoholic extract of the raspberries were determined. The effect of growing technologies, i.e., conventional vs. nutrient substrate, on the accumulation of macro- and microelements in raspberry fruits was established. In red raspberries grown on nutrient substrate, the antioxidant activity decreased by 25 times (aqueous extract) and 1.5 times (alcoholic extract). The K and Na contents and Se contents of red raspberries grown on nutrient substrate were 1.5 and 3 times higher than those of raspberries of grown with conventional technology. Raspberries grown with conventional technology contained 2 times more Ca, Ni, and Mn and 7.4 times more Fe than raspberries grown on nutrient substrate. The total amount of elements in raspberries grown through soilless cultivation was 5.5% higher than that in berries grown conventionally. A total of 48 compounds were identified in the alcoholic extracts, and only 29 substances were found in berries grown on a nutrient substrate. Sugar and citric acid constituted the largest share of red raspberry components. Fructose and turanose disaccharide synthesis in raspberries grown on nutrient substrate was 20% higher than that in conventionally grown raspberries. A total of 48 organic compounds with different biological activities were identified. They included five substances with antimicrobial activity, three phenolic substances, eight organic acids, four sugar acids, nine amino acids, and 19 sugars and their derivatives. At the same time, 42 compounds were found in raspberries grown with traditional technology, and 21 compounds were identified in raspberry fruits grown on nutrient substrate. Three fatty acids, namely, ɑ-linoleic acid (polyunsaturated omega-6 fatty acid), palmitic acid, and stearic acid (saturated fatty acid), along with cinnamic acid, shikimic acid, and chrysin were found in berries grown conventionally.

Changes in the Polyphenol Content of Red Raspberry Fruits during Ripening

Berry fruits that contain large amounts of polyphenol compounds are expected to exhibit health and anti-aging effects due to the antioxidant activities of these components. Among the various polyphenols, flavan-3-ol derivatives are known to have a particularly high functionality. In this study, the maturity of red raspberry fruits is classified into eight stages based on the polyphenol content at each stage. Quantification of the various compounds and investigation of the DPPH and ABTS radical scavenging activities were carried out. The total polyphenol content, including that of the flavan-3-ol derivatives, was the highest in immature fruits, gradually decreasing during fruit maturation, during which the radical scavenging activity also decreased. Based on our quantitative results, it was considered that the decrease in the flavan-3-ol derivative content due to fruit ripening was largely related to the increase in the amount of anthocyanin derivatives. Considering that the decreased contents of these compounds were related to the expression levels of polyphenol biosynthetic enzymes, quantification was performed using the semi-quantitative polymerase chain reaction, but the only change observed was the increased expression of the enzyme that synthesizes anthocyanins during maturation. Therefore, it was suggested that it is necessary to inhibit anthocyanin synthesis to increase the contents of highly functional flavan-3-ol derivatives in the mature fruit.

Micropropagation of Raspberries (Rubus idaeus L.) in Liquid Media by Temporary Immersion Bioreactor in Comparison with Gelled Media

Temporary Immersion Bioreactor (TIB) is a suitable technique for large scale micropropagation of plant species. The aim of this work was to test the capacity of in vitro proliferation of the primocane-fruiting red raspberry cv Maravilla and floricane-fruiting red raspberry cv Willamette on gelled media compared to liquid media. The two varieties were cultured in vitro on two media, Murashige and Skoog 1962 (MS) and Driver and Kuniyuki walnut medium, 1984 (DKW), both supplemented with 0.5 mg/l 6-benzyladenine (BA). In the control cultures on gelled media the media were gelled with 5g/l Plant Agar, whereas for the cultures in liquid media Plantform bioreactors were used. After six weeks of in vitro culture we recorded the proliferation rates and lengths of the axillary shoots obtained in all the experimental treatments. The highest proliferation rate was 16 ± 2.03, obtained in cv. Willamette on gelled MS medium with 0.5 mg/l BA. The longest shoots (3.17 ± 0.32 cm) were obtained at cv. Maravilla on the DKW medium with 0.5 mg / l BA in the bioreactor. Our research highlighted that Rubus idaeus L. Maravilla and Willamette can be TIB propagated, although further research is needed to improve the efficiency of this method.

Fruit Qualities of Interspecific Hybrid and First Backcross Generations between Red Raspberry and Rubus parvifolius

Interspecific hybridization is useful in raspberry (Rubus idaeus L. ssp. idaeus) breeding to introgression of traits such as heat or cold tolerance, and excellent fruit qualities. Rubus L. wild species in Asia, including Rubus parvifolius L., have been attracting a great deal of attention as sources of new traits in breeding raspberry and blackberry (Rubus fruticosus Agg.). We previously developed and selected IPI-1 and IPI-3 first backcross (BC1) hybrids, [‘Indian Summer’ (R. idaeus ssp. idaeus) × R. parvifolius] × ‘Indian Summer’, as raspberry cultivars adapted to the warm climate in parts of Japan. In this study, we investigated the growth, morphological traits, and fruit qualities, such as sugar, organic acid, anthocyanins, and carotenoids, of each of these IPI lines over a 2-year period to discern their potential as commercial raspberry cultivars. IPI lines had the characteristic of primocane fruit with overflowing from side buds while the parent, IP-1 (‘Indian Summer’ × R. parvifolius), did not. IPI lines showed significantly lower values in anthocyanin content than red raspberry ‘Skeena’, while showing higher carotenoid contents. This study is the first research about fruit qualities such as anthocyanin and carotenoid content of BC1 hybrids using Japanese wild Rubus species.