Optimization of Enzyme-Assisted Extraction of Bioactive Compounds from Sea Buckthorn (Hippophae rhamnoides L.) Leaves: Evaluation of Mixed-Culture Fermentation.

Hippophae rhamnoides L. leaves possess a remarkable amount of polyphenols that could serve as a natural remedy in various applications. In comparison, numerous techniques, such as conventional and high-pressure techniques, are available for extracting the bioactive fractions from sea buckthorn leaves (SBL). However, enzyme-assisted extraction (EAE) of SBL has not been comprehensively studied. The aim of this study was to optimize critical EAE parameters of SBL using the cellulolytic enzyme complex, Viscozyme L, to obtain a high-yield extract with a high concentration of bioactive compounds. In order to determine the optimal conditions for EAE, the study employed a central composite design and response surface methodology to analyze the effects of four independent factors (pH, temperature, extraction time, and enzyme concentration) on two different responses. Our findings indicated that under optimal conditions (3:15 h extraction, temperature 45 °C, pH 4.9, and 1% Viscozyme L v/w of leaves DW), EAE yielded 28.90 g/100 g DW of the water-soluble fraction. Furthermore, the EAE-optimized liquid extract was continuously fermented using an ancient fermentation starter, Tibetan kefir grains, which possess lactic acid bacteria (LAB) and have significant potential for use in biopreservation. Interestingly, the results indicated various potential prebiotic characteristics of LAB. Additionally, alterations in the cell wall morphology of the SBL residue after EAE were examined using scanning electron microscopy (SEM). This study significantly optimized EAE parameters for sea buckthorn leaves, providing a promising natural source of bioactive compounds for various applications, such as nutraceuticals, functional foods, and high-value products.

Effect of molecular weight of chitosan on the shelf life and other quality parameters of three different cultivars of Actinidia kolomikta (kiwifruit).

The kiwi fruit, Actinidia kolomikta, has valuable properties such as high antioxidant activity, high vitamin C, polyphenols, chlorophylls and organic acids content, but the species are hardly commercialized due to their short shelf life (less than two days). In this study three different cultivars of A. kolomikta (Anyksta, Sentiabrskaya and VIR2) were coated with low, medium and high molecular weight chitosan bio-polymer with the aim to extend the shelf life. The changes in fruit firmness, mass, phenolic compound content, vitamin C content and subjective criteria (withering level, decoloration level and aesthetic appearance) were monitored. It was observed that high molecular weight chitosan had higher positive effect on the shelf life of Sentiabrskaya and Anyksta cultivars than VIR2. Low molecular weight chitosan was found effective on VIR2.

Chitosan coating of red kiwifruit (Actinidia melanandra) for extending of the shelf life.

Commercial production of red kiwifruit (Actinidia melanandra) has been unsuccessful because of its short shelf life. Here in this study, we used chitosan to extend the shelf life of red kiwifruit berries. Chitosan (with 70-75% deacetylation degree and low molecular weight) was dissolved in acetic acid (at pH 2.0-2.3) to obtain gel material, which was used for coating of the fruit. The coated and uncoated samples were kept for 26 days at room temperature (20±2°C). The changes in the weight loss, firmness, soluble solid content, total polyphenol content and ascorbic acid content were evaluated. All these findings showed that chitosan could be an effective coating material for berries of red kiwifruit to extend its short shelf life.

Antioxidant properties, phenolic composition and potentiometric sensor array evaluation of commercial and new blueberry (Vaccinium corymbosum) and bog blueberry (Vaccinium uliginosum) genotypes.

Antioxidant properties of juices of newly bred and known blueberry (Vaccinium corymbosum) genotypes and wild bog blueberry (Vaccinium uliginosum) were evaluated by ABTS(+) scavenging capacity (RSC), ferric reducing antioxidant power (FRAP), oxygen radical absorbance capacity (ORAC), total phenolic content (TPC) and total anthocyanin content (TAC) assays. TPC varied in the range of 0.85-2.81 mg gallic acid equiv./mL, RSC, FRAP and ORAC values were 6.38-20.9, 3.07-17.8 and 4.21-45.68 µmol Trolox equiv./g, respectively. New blueberry genotypes and bog blueberry demonstrated stronger antioxidant properties and TAC than other studied genotypes. The content of quinic (203-3614 µg/mL), chlorogenic (20.0-346.8 µg/mL) acids and rutin (0.00-26.88 µg/mL) measured by UPLC/ESI-QTOF-MS varied depending on the genotype. Juices were evaluated by electronic tongue; PCA score plot showed that the method discriminates different genotypes although some juice samples were located very closely and overlapping. Significant differences were observed between L(∗), a(∗), b(∗) colour parameters of some genotypes.

Antioxidant properties and polyphenolic compositions of fruits from different European cranberrybush (Viburnum opulus L.) genotypes.

Antioxidant properties of fruit juices of six Viburnum opulus genotypes were evaluated by DPPH, ABTS(+) radical scavenging capacity (RSC), ferric reducing antioxidant power (FRAP), oxygen radical absorbance capacity (ORAC) and Folin-Ciocalteu total phenolic content (TPC) assays. TPC varied in the range of 5.4-10.6 mg gallic acid equivalents/g, RSC (ABTS(+)), FRAP and ORAC values were 31.9-109.8, 32.3-61.8 and 141.6-260.4 µmol trolox equivalents/g, respectively. V. opulus var. sargentii fruit juice was a remarkably stronger antioxidant than the other five V. opulus genotypes. The content of chlorogenic acid (the main phenolic compound in berry juices) depending on plant cultivar varied in the range of 0.54-6.93 mg/ml. The RSC of individual constituents was measured by the on-line HPLC-UV-DPPH method: chlorogenic acid was the dominant radical scavenger in V. opulus P3 (74%), while epicatechin and catechin (the main antioxidants in V. opulus var. sargentii) contributed to 40% and 23% of the total RSC for the sargentii genotype. Nine constituents were identified in V. opulus juice by using ultra high performance liquid chromatography coupled to quadruple and time-of-flight mass spectrometers (UPLC-QTOF-MS). In general, the study demonstrated that V. opulus var. sargentii followed by V. opulus P3 and V. opulus var. americanum possessed the highest antioxidant capacity. The obtained results may assist in selecting the most valuable V. opulus genotypes for the production of fruits possessing strong antioxidant capacity and containing beneficial phenolic constituents.