Chokeberry Juice Research Articles

Formulation of a Wort-Based Beverage with the Addition of Chokeberry (Aronia melanocarpa) Juice and Mint Essential Oil

In Croatia, the production of non-alcoholic wort-based beverages is in its initial stages. The main goal of this research was to produce wort that could be then used in the production of a wort-based beverage with the addition of chokeberry (Aronia melanocarpa) juice. Sensory characteristics and consumer acceptance was also analyzed. Worts were prepared by the standard mashing process, using Munich and pale ale malt. Chokeberry juice was added to the cooled worts. For the purpose of this research, two versions of wort with different concentrations of chokeberry juice (10%, 20%, 30%) were formulated, and all of the beverages were subjected to sensory analysis. Sensory analysis showed that wort with the addition of 30% chokeberry juice was the most accepted. This concentration of chokeberry juice gave the beverage a pleasant taste, but needed some improvement. To address this, mint essential oil was added to the mixture and carbonation using gaseous CO2 was conducted. This beverage received better acceptance when carbonated and mixed with mint essential oil. In addition to the sensory analysis, the polyphenol content of the chosen beverage was also analyzed, along with its nutritional value. Polyphenol content was 2621.47 mg/L and antioxidative activity was 2.28 mmol Trolox/L. The energy value was determined to be 57 kcal. However, in order to optimize the production of this wort-based beverage, further research should be conducted.

The Influence of the Use of Different Polysaccharide Coatings on the Stability of Phenolic Compounds and Antioxidant Capacity of Chokeberry Hydrogel Microcapsules Obtained by Indirect Extrusion.

The aim of the study was to evaluate the effect of the use of different polysaccharides and their mixtures on the structure of chokeberry hydrogel microcapsules and the stability of polyphenolic compounds and antioxidant capacity during one month of refrigerated storage. As a coating material, alginate and its mixtures with pectin, carrageenan, and chitosan were used, while chokeberry juice and preparation of polyphenolic compounds were used as a core. In non-stored capsules, the addition of carrageenan, pectin, and chitosan to alginate increased the content of total polyphenolic compounds and antioxidant capacity. When compared to non-encapsulated juice, the capsules had a greater decrease in antioxidant capacity during storage. The coating variant composed of alginate and carrageenan was found to be the most beneficial for the preservation of the capsules' phenolic compounds. The findings revealed that proper polysaccharide coating selection is critical for the proper course of the microencapsulation process, the polyphenolic content of chokeberry capsules, and their antioxidant properties.

Effects of adding different quantities of yeast and chokeberry juice on fermentation of mead

Honey is a product of high nutritional value, used as a raw material for obtaining mead. However, adding fruit juices, including chokeberry juice, can improve mead quality. This paper aims to assess the effects that adding different quantities of chokeberry juice, with the variation of 3 amounts of inoculated yeast, has on the fermentation and physicochemical, antioxidant, and antimicrobial properties of mead. The parameters analyzed are the dry matter content, pH value, and content of volatile acids, ethanol and methanol, total phenols and flavonoids, FRAP, DPPH, and ABTS tests, and antimicrobial properties. The results obtained in this paper show that adding chokeberry juice improves the antioxidant properties of the final product and positively affects the course of mead fermentation, i.e., it has led to an increase in the maximum concentration of ethanol. Regarding the chemical composition of mead, there is no significant difference, except in the obtained ethanol content, which is the highest in samples with 10% of added chokeberry juice. Furthermore, the control sample showed the best antimicrobial activity, while the sample with 5% added chokeberry juice showed the weakest effect. Finally, the strongest effect was seen in the sample with 20% of added chokeberry juice.

THE EFFECT OF STORAGE TIME ON SELECTED QUALITY CHARACTERISTICS OF MIXED JUICES MADE FROM BLACK CHOKEBERRY AND HONEYSUCKLE BERRY

Background. Consumer awareness of a healthy lifestyle is gradually growing. Fruits are a rich source of health-promoting anthocyanins or polyphenols. The aim of the research was to determine the effect of the storage time of mixed juices made from black chokeberry and honeysuckle berry on selected quality characteristics. In this study, it was hypothesized that the storage time of mixed juices would be a factor affecting the content of polyphenols, anthocyanins and color. The test material included black chokeberry and honeysuckle berry juices and mixed juices with a share of juices in the range of 10 ÷ 90 %. Results and conclusions. The honeysuckle berry juice proved to be a more valuable source of poly phenols and anthocyanins (308.3 and 234.5 mg/100 cm3 ) than the chokeberry juice (229.9 mg and 122.2 mg/100 cm3 ). Similarly, the mixed juices with a higher share of honeysuckle berry juice were char acterized by a higher content of these compounds, and consequently, a potentially higher health-promoting value. The highest value of L*, a* and b* was found in the 100 % black chokeberry sample. For storage, it was demonstrated that the most intense degradation changes in the bioactive components took place in the first month, whereas in the later period, the rate of changes in these compounds was lower. The one-month storage resulted in a decrease in the content of polyphenols by 12.1 ÷ 14.2 % and anthocyanins by 19.7 ÷ 33.5 %, depending on the juice variant. In the case of color, it was observed that extending the storage time had a significant effect on the brightening of the tested products, as well as on changes in the values of the a* and b*.

Toward gentle chokeberry juice production by ultrasound-assisted enzymatic maceration

Sustainable processes accompanied by high extraction yields and minimized amounts of by-products are a major goal of current fruit juice production. Controlled degradation of cell wall polysaccharides, in particular pectin, may contribute to reduced emergence of side streams. Possible strategies for the optimization are the selection of enzyme preparations based on comprehensive studies of their activities, the adjustment of maceration temperature toward more gentle conditions, and the application of alternative technologies such as ultrasound (US) during maceration. The present study provides insights into the effects of ultrasound-assisted enzymatic maceration (UAEM) on pectin degradation, total anthocyanin content, thermal and storage stability, and juice yield during chokeberry juice production on pilot-plant scale. The two enzyme preparations applied predominantly possessed polygalacturonase or pectin lyase activity. Cell wall polysaccharide degradation was improved by US and resulted in a 3% increase in juice yield by UAEM using an enzyme preparation that shows mostly polygalacturonase activity. Thermostability of anthocyanins was improved in juices produced using pectin lyase and applying US and matched the stability of anthocyanins in juices produced using polygalacturonase. Storage stability of anthocyanins was improved in juice produced using polygalacturonase during UAEM. UAEM also resulted in lower yields of pomace making the production more resource-efficient. Overall, the use of polygalacturonase has promising potential to advance conventional chokeberry juice production by applying US at gentle conditions.

TECHNOLOGY FOR LYOPHILIZED FUNCTIONAL PRODUCT PRODUCTION ON THE BASIS OF BUFFALO COLOSTRUM

A technology for obtaining a new lyophilized functional product with healthy qualities - ''FucoSTEM'' has been created. Its composition includes sources of useful and biologically active ingredients of various origins. The bioformula of the new bioproduct was complied with the requirements for physiological activity, harmlessness and microbial stability. The main parameters of the process of freeze-drying of 4 main components of the composition of the product - colostrum, chokeberry juice, beta-glucans and fructooligosaccharides were established, and their phase behavior at low and high temperatures was studied. Analysis of the thermal curves, obtained by differential scanning calorimetry, provides information on enthalpy, melting temperatures and crystallization, thus proving that an endothermic phenomenon between -5°C and -40°C is observed, which corresponds to the melting of the samples.

Evaluation of Chokeberry/Carboxymethylcellulose Hydrogels with the Addition of Disaccharides: DART-TOF/MS and HPLC-DAD Analysis

With the growing awareness of the importance of a healthy diet, the need for the development of novel formulations is also on the rise. Chokeberry products are popular among consumers since they are a rich source of polyphenols that are responsible for antioxidant activity and other positive effects on human health. However, other natural food ingredients, such as disaccharides, can affect their stability. The aim of this study was to investigate the influence of disaccharides addition on the polyphenol composition of chokeberry hydrogels. Hydrogels were prepared from chokeberry juice and 2% of carboxymethylcellulose (CMC) with the addition of 30%, 40%, or 50% of disaccharides (sucrose or trehalose). Samples were analyzed using DART-TOF/MS. The method was optimized, and the fingerprints of the mass spectra have been statistically processed using PCA analysis. Prepared samples were evaluated for total polyphenols, monomeric anthocyanins, and antioxidant activity (FRAP, CUPRAC, DPPH, ABTS assays) using spectrophotometric methods. Individual polyphenols were evaluated using HPLC-DAD analysis. Results showed the addition of disaccharides to 2% CMC hydrogels caused a decrease of total polyphenols. These findings confirm proper formulation is important to achieve appropriate retention of polyphenols.

Compositional characteristics, health benefit and risk of commercial bilberry and black chokeberry juices

An insight into chemical composition, nutritional value and potential health risk of increasingly popular bilberry and black chokeberry commercial juices was provided, based on HPLC-UV (anthocyanins and non-anthocyanin phenolics; patulin; hydroxymethylfurfural), AAS (minerals) and ICP-MS (trace elements) analyses. Delfinidin (in bilberry) and cyanidin glycosides (in bilberry and chokeberry) were the most abundantly present anthocyanins, chlorogenic acid dominated among non-anthocyanin polyphenols, while mineral composition revealed high K and desirable low Na content. A glass of blueberry/black chockeberry juice (200 mL) per day could provide up to 63.5/27.0 mg of anthocyanins, 147.2/314.0 mg of polyphenols, almost 50% of Mg (the only mineral satisfying the requirement for a nutritional claim) and, in case of chokeberry, 20% of Mn adequate intake. No health risk was observed related to any of the investigated toxicants. Despite indications of a possible benefitial role for health, observed compositional variations precluded positioning of berry juices as functional foods. The labelling could help specialist in nutrition and functional foods as well as health-conscious consumers seeking foods with reliable quantity of dietary valuable phytochemicals and minerals. Sufficiently characterised food has been one of the prerequisites for the approval of a health claim, along with sufficiently defined and substantiated claimed effect.

Chokeberry juice affects membrane lipid status and cellular antioxidant enzymes in healthy women with aerobic training activity

The present study examined the effects of aerobic training alone or combined with chokeberry juice on membrane lipid status and activities of antioxidant enzymes in non-athlete women. Participants were randomly assigned into the training group performing aerobic training three times per week; the chokeberry-training group followed the same training regime and additionally consumed 100 ml of chokeberry juice per day and the control group neither trained nor consumed the juice. Blood samples were collected at baseline and the end of the eight-week-long intervention. Membrane fatty acids’ composition was analyzed by gas-liquid chromatography, while the activities of antioxidant enzymes were measured by spectrophotometry. As a result, the n-3 fatty acids’ content was significantly higher in the chokeberry-training (median (interquartile range) of 5.96 (1.65) %) compared with the control group (5.12 (0.87) %), while saturated fatty acids’ content was lower in the chokeberry-training (40.14±1.19 %) than in the training group (42.59±2.29 %). We detected significantly higher activity of superoxide dismutase in the training (2224 (2170) U/gHb) compared with the chokeberry-training (1252 (734) U/gHb) and control group (1397 (475) U/gHb). Our study indicates that supplementation with chokeberry juice may induce favorable changes in cell fatty acid composition and antioxidant response in women performing aerobic training.

Chokeberry juice affects membrane lipid status and cellular antioxidant enzymes in healthy women with aerobic training activity

The present study examined the effects of aerobic training alone or combined with chokeberry juice on membrane lipid status and activities of antioxidant enzymes in non-athlete women. Participants were randomly assigned into the training group performing aerobic training three times per week; the chokeberry-training group followed the same training regime and additionally consumed 100 ml of chokeberry juice per day and the control group neither trained nor consumed the juice. Blood samples were collected at baseline and the end of the eight-week-long intervention. Membrane fatty acids’ composition was analyzed by gas-liquid chromatography, while the activities of antioxidant enzymes were measured by spectrophotometry. As a result, the n-3 fatty acids’ content was significantly higher in the chokeberry-training (median (interquartile range) of 5.96 (1.65) %) compared with the control group (5.12 (0.87) %), while saturated fatty acids’ content was lower in the chokeberry-training (40.14±1.19 %) than in the training group (42.59±2.29 %). We detected significantly higher activity of superoxide dismutase in the training (2224 (2170) U/gHb) compared with the chokeberry-training (1252 (734) U/gHb) and control group (1397 (475) U/gHb). Our study indicates that supplementation with chokeberry juice may induce favorable changes in cell fatty acid composition and antioxidant response in women performing aerobic training.

Spray Drying of Chokeberry Juice—Antioxidant Phytochemicals Retention in the Obtained Powders versus Energy Consumption of the Process

The production of chokeberry powder, an important functional additive in food, should exhibit both maximization of bioactive properties retention and minimization of energy consumption. The process of spray drying chokeberry juice on a maltodextrin carrier was tested on a semi-technical scale. The research scope included the variability of the inlet air temperature in the range of T = 150–185 °C and concentration of the feed solution in the range of Ud.m = 15–45% d.m. The powder yield, energy consumption and bioactive properties of the obtained powders were determined. The highest levels of bioactive properties retention were expressed in total polyphenol content (TPC) and anthocyanin content (AC) and obtained at T = 150 °C and Ud.m = 25–30% d.m. However, the most advantageous process parameters in terms of specific energy consumption (SEC) minimization were T = 160–170 °C and Ud.m = 30–35% d.m. Analysis of the dependence on SEC versus TPC and SEC versus AC showed that the most favorable drying parameters for chokeberry juice were as follows: inlet air temperature T = 170 °C and feed solution concentration Ud.m = 35%. Hence, under such process conditions, chokeberry powders were produced with approx. 3% lower bioactive properties retention (in relation to the maximum values), but with 20.5% lower SEC.

Quality Changes in Black Chokeberry Juice Treated by Thermal-Assisted High Hydrostatic Pressure during Cold Storage.

The effects of thermal-assisted high hydrostatic pressure (TAHHP), high hydrostatic pressure (HHP), and thermal pasteurization (TP) treatments on the quality of aronia juice were evaluated in this study. The results showed that TAHHP and HHP significantly decreased the aerobic plate counts of aronia juice. No significant differences in terms of physicochemical properties, such as pH and total soluble solids, were observed between aronia juice treated with high pressure or thermal pasteurization treatment after 28 days of storage. TAHHP and HHP affected the colour and antioxidant characteristics of aronia juice, though to a significantly lower extent than TP. This result demonstrates that TAHHP and HHP can better maintain the original quality of aronia juice than TP. In summary, both TAHHP and HHP can maintain the microbiological safety and original quality characteristics of aronia juice. TAHHP can effectively increase the safety and duration of cold storage of aronia juice, and hence is highly useful for the juice industry.

Quality Characteristics, Anthocyanin Stability and Antioxidant Activity of Apple (Malus domestica) and Black Chokeberry (Aronia melanocarpa) Juice Blends.

Black chokeberries are a valuable source of anthocyanins and other phenolic compounds, but they are underutilized due to their unpalatable astringent taste. The aim of this study was to determine the potential of using black chokeberry juice as a health-promoting ingredient in apple juice with a view to develop a new functional food product and to increase the dietary consumption of bioactive compounds. Mixed juices were prepared from apple (A) juice and black chokeberry (BC) juice at 95:5 (ABC5), 90:10 (ABC10), 85:15 (ABC15), and 80:20 (ABC20) volumetric ratios. Comparative studies on the effect of heat treatment (90 °C, 10 min) and storage (four months, 20 °C) on the physicochemical and antioxidant properties of apple, black chokeberry, and mixed juices were carried out. The soluble solids content, titratable acidity, total phenolic, total anthocyanin and ascorbic acid content, and antioxidant activity increased while the total soluble solids/titratable acidity ratio decreased with increasing addition levels of BC juice. Mixing A juice with BC juice at 95:5 and 90:10 volumetric ratios improved the color and enhanced the palatability and general acceptability of the juice. The percentage losses of anthocyanins and polyphenols registered after heat treatment and storage increased with increasing addition levels of BC juice.

Contemporary nutrition-based interventions to reduce risk of infection among elderly long-term care residents: A scoping review.

BackgroundElderly long-term care residents (ELTCRs) face considerable burden of infection, especially evident during the COVID-19 pandemic. The nutritional status of the host can influence susceptibility to infection by altering immune system integrity, therefore, nutrition-based interventions may be a viable complement to existing infection prevention measures.ObjectiveThis scoping review sought to identify nutritional interventions and factors that have the strongest evidence to benefit ELTCRs, and thus best poised for rigorous clinical trial evaluation and subsequent implementation.MethodsA database search of OVID-Medline, OVID-Embase, and Web of Science was performed from 2011 to 2021 to identify nutritional intervention studies which attribute to changes in infection in contemporary ELTCR settings. Articles were screened in duplicate and data extraction completed by a single reviewer, while a second reviewer verified the data which was fitted to identify evidence for nutritional interventions related to reducing rates of infection among ELTCRs.ResultsThe search identified 1018 studies, of which 11 (nine clinical trials and two observational cohort studies) satisfied screening criteria. Interventions that significantly reduced risk of infection included whey protein (any infection), Black Chokeberry (urinary tract infection), and vitamin D (acute respiratory tract infection, skin and soft tissue infection). Both zinc and a dedicated meal-plan significantly improved lymphocyte parameters. Vitamin D deficiency was associated with the development of respiratory tract infections. Probiotic and soy-based protein interventions did not significantly affect risk of infection or lymphocyte parameters, respectively.ConclusionThe current scoping review was effective in identifying the use of nutrition-based interventions for infection prevention among ELTCRs. In this study, some nutrition-based interventions were observed to significantly influence the risk of infection among ELTCRs. Nutritional interventions such as vitamin D (preventing deficiency/insufficiency), Black Chokeberry juice, zinc gluconate, whey protein, and varied and nutrient dense meal plans may be suitable for future rigorous clinical trial evaluation.

Antioxidant and Antimicrobial Properties of Selected Fruit Juices

Fruit and fruit juices are a valuable source of bioactive compounds, which can protect our organisms from oxidative stress. The phenolic compounds and other phytochemicals may affect the antimicrobial properties of juices. The aim of this study has been to evaluate antioxidant and antimicrobial properties of selected berry juices and vitamin C-rich fruit juices. The research material was composed of seven juices, including three from berries (elderberry chokeberry, cranberry), three from vitamin C-rich fruit (sea buckthorn, wild rose, Japanese quince) and one exotic juice from noni fruit. Antioxidant capacity, total polyphenol, total flavonoid and total anthocyanin content were determined. Furthermore, the antimicrobial activity and the minimal inhibitory concentration (MIC) as well as the minimal bactericidal concentration (MBC) were evaluated. The research showed that fruit juices from wild rose, chokeberry and Japanese quince had the highest antioxidant capacity. These juices were characterised by the rich content of polyphenols. Elderberry and chokeberry juices had the highest total anthocyanins. The juices differed in the content of bioactive compounds and specific bactericidal properties against Gram-positive or Gram-negative bacteria. Fruit juices from cranberry, Japanese quince and sea buckthorn had the highest antimicrobial activity. Wild rose, chokeberry and elderberry juices, despite their high antioxidant properties, showed antimicrobial activity only against Gram-positive strains, except Enterococcus faecalis and Clostridium perfringens. Significant differences in the content of bioactive compounds in fruit juices affect the antimicrobial properties juices.

Selected Properties of Juices from Black Chokeberry (Aronia melanocarpa L.) Fruits Preserved Using the PEF Method

Black chokeberry (Aronia melanocarpa L.) fruit and processed berries have very high biological value because they are a rich source of bioactive compounds. The method of black chokeberry juice preservation is of key importance. One of the more recent ways in which semiliquid and liquid products can be preserved is the pulsed electric field (PEF) method. The aim of our study was to compare chosen physical and chemical properties of fresh and PEF-preserved chokeberry fruit juices derived from farms located in the vicinity of Cracow (Kraków). The analysis focused on the physical properties and chemical composition of black chokeberry juices, their bioactive compound content, and antioxidant activity. After using the PEF method, there was an increase in dry weight, sugars, and polyphenols, which could be caused by the slight evaporation of water during the process. During this process, antioxidant activity decreased, and ultra-weak luminescence slightly increased. The process of preserving juices using the PEF method is a good way to preserve the bioactive properties of the obtained aronia juices.

Comparative Phytochemical Analysis of Aronia melanocarpa L. Fruit Juices on Bulgarian Market.

Aronia melanocarpa L. (black chokeberry), belonging to the Rosaceae family, contains high amounts of polyphenolics and therefore exhibits one of the highest antioxidant and anti-inflammatory activities among berry fruits. Chokeberries are used in the food industry for juice, nectar, and wine production and as colorants. We aimed to compare the phytochemical composition of three chokeberry juices commercially available in the local market as sources of beneficial phytochemicals. Using GC–MS and LC–MS/MS, we performed the identification and quantitation of polar compounds and polyphenolics. The concentrations of 13 amino acids, including 6 essential amino acids, 10 organic acids, 20 sugar alcohols and derivatives, 14 saccharides, 12 fatty acids and esters, and 38 polyphenols, were estimated. One of the analyzed juices had the highest polyphenolic content (5273.87 ± 63.16 µg/mL), possibly due to 2.9 times higher anthocyanin concentration compared to anthocyanins in other tested juices. This study provides new data concerning phytochemical composition in terms of amino acids, organic acids, sugar acids, fatty acids and their esters, and polyphenols as phytocomponents of commercially available chokeberry juices. Results show that after all processing techniques and possibly different plant growth conditions, chokeberry juices are a valuable source of health-promoting phytochemicals such as phenolic acids, pro-anthocyanins, and anthocyanins, thus considering them as functional foods. We demonstrated a diversity of the active substances in bioactive foods marketed as “same”; therefore, the standardized therapeutic effect could be expected only by the utilization of food supplements with guaranteed constant content.

Recent advances on the stability of dietary polyphenols

Recent advances on the stability of dietary polyphenols

Chokeberry Reduces Inflammation in Human Pre-adipocyte Cells

ObjectivesChokeberry, Aronia melanocarpa, consumed as a fruit and used as a traditional food by some American Indian tribes has greater levels of anthocyanin compared to cranberries and blueberries. Animal and human studies demonstrate that chokeberry juice extract (CBE) has cardioprotective, anti-diabetic, and anti-inflammatory properties. Saturated fatty acids including palmitate (PA, 16:0) and lipopolysaccharide (LPS) produces pro-inflammatory effects by inducing inflammatory gene expression. The objective of this study was to determine the effect that CBE, Cyanidin 3-O-galactoside (C3Gal) and Cyanidin 3-glucoside(C3G) have on PA or LPS induced inflammation as measured by interleukin-6 (IL-6). MethodsHuman primary subcutaneous pre-adipocyte cells (ATCC, Manassas, Virginia) were pretreated with either 2 uM C3Gal or CBE for three hours. Following pretreatment, cells were treated with 0.17 mM bovine serum albumin (BSA) for control; 0.1 mM PA; BSA in presence of 2uM C3Gal or CBE; and PA in presence of 2 uM C3Gal or CBE. RT-qPCR analysis was conducted to determine IL-6 mRNA expression normalized to 18s rRNA expression. One-way ANOVAs were run to determine significance of group differences. ResultsTreatment of cells with PA increased (P < 0.0001) IL-6 mRNA compared to control and CBE groups. Treatment of cells with CBE decreased (P < 0.0001) PA-induced IL-6 mRNA while C3Gal did not (p = 0.4657). Treatment of cells with CBE decreased (P < 0.0001) LPS-induced IL-6 mRNA while C3G treatment did not (p = 0.4537). ConclusionsPA induces inflammation, as measured by IL-6 mRNA expression, in human primary subcutaneous pre-adipocyte cells. This inflammation is reduced by treatment with CBE while isolated anthocyanin such as C3- galactoside or glucoside has partial inhibition. Future studies will identify additional chokeberry anthocyanins and flavonoids important in anti-inflammatory effects. Funding SourcesThis work was funded by grant support from the USDA Agricultural Research Service Project and NIH National Institute of General Medical Sciences, The Centers of Biomedical Research Excellence Award.

Optimization of the ultrasound-assisted extraction of polyphenols from Aronia and grapes

The extraction of phenolics and tannins from cold-hardy grapes is not maximized with the current methods, which lead to unbalanced wines. This study aims to investigate high-power sonication to improve polyphenolic content in cold-hardy grape juice in comparison with chokeberry juice. Three solid to solvent ratios and times were applied on chokeberry and ‘Marquette’ grape berries using 50% ethanol or 13% acidified ethanol and compared to a conventional extraction technique. Iron-reactive phenolic compounds, tannins content, and color were analyzed during the extractions using UV–Visible spectrophotometry, and anthocyanin content was analyzed using HPLC-DAD. At the 1:2 solid to solvent ratio, the color intensity, phenolics, and tannins content were improved using the ultrasound-assisted extraction on chokeberries. However, the tannin content of ‘Marquette’ berries remained the same with both techniques and solvents, suggesting that the plant cell wall structure may have a strong impact on the retention of tannins from cold-hardy grapes.