Sensory quality and compositional characteristics of blackcurrant juices produced by different processes

Astringency and its sub-qualities: a review of astringency mechanisms and methods for measuring saliva lubrication

Astringency is an important mouthfeel attribute that influences the sensory experiences of many food and beverage products. While salivary lubricity loss and increased oral friction were previously believed to be the only astringency mechanisms, recent research has demonstrated that nontactile oral receptors can trigger astringency by responding to astringents without mechanical stimulation. Various human factors have also been identified that affect individual responses to astringents. This article presents a critical review of the key research milestones contributing to the current understanding of astringency mechanisms and the instrumental approaches used to quantify perceived astringency intensity. Although various chemical assays or physical measures mimic in-mouth processes involved in astringent mouthfeel, this review highlights how one chemical or physical approach can only provide a single measure of astringency determined by a specific mechanism. Subsequently, using a single measurement to predict astringency perception is overly idealistic. Astringency has not been quantified beyond the loss of saliva lubrication; therefore, nontactile receptor-based responses must also be explored. An important question remains about whether astringency is a single perception or involves distinct sub-qualities such as pucker, drying, and roughness. Although these sub-quality lexicons have been frequently cited, most studies currently view astringency as a single perception rather than dividing it into sub-qualities and investigating the potentially independent mechanisms of each. Addressing these knowledge gaps should be an important priority for future research.

Pullulanase: unleashing the power of enzyme with a promising future in the food industry

Pullulanases are the most important industrial group of enzymes in family 13 glycosyl hydrolases. They hydrolyze either α-1,6 and α-1,4 or both glycosidic bonds in pullulan as well as other carbohydrates to produce glucose, maltose, and maltotriose syrups, which have important uses in food and other related sectors. However, very less reports are available on pullulanase production from native strains because of low yield issues. In line with the increasing demands for pullulanase, it has become important to search for novel pullulanase-producing microorganisms with high yields. Moreover, high production costs and low yield are major limitations in the industrial production of pullulanase enzymes. The production cost of pullulanase by using the solid-state fermentation (SSF) process can be minimized by selecting agro-industrial waste. This review summarizes the types, sources, production strategies, and potential applications of pullulanase in different food and other related industries. Researchers should focus on fungal strains producing pullulanase for better yield and low production costs by using agro-waste. It will prove a better enzyme in different food processing industries and will surely reduce the cost of products.

Identification of key astringent compounds in aronia berry juice

Aronia berry has extremely strong and unpleasant astringent mouthfeel. However, detailed information on the key astringent compounds is still limited. To fill this gap, astringent compounds were firstly separated from aronia juice. Following sensory evaluation, phenolic profile determination, validation by in-vitro models, and thiolytic degradation, key astringent compounds were identified. Results showed when most proanthocyanidins (PAs) were removed while other phenolic compounds remained, the astringency intensity of aronia juice was significantly decreased. In-vitro models, including saliva precipitation index and mucin turbidity, validated PAs rather than anthocyanins as the key astringent compounds. The protein-precipitated PAs from aronia juice were identified as polymers, linked by B-type bonds, with (-)-epicatechin as the extension unit and predominantly as the terminal unit, having a 69.56 mean degree of polymerization (mDP), far higher than the 35.38 mDP of PAs separated directly from juice. These findings would be valuable to the development of targeted astringency mitigation approaches.

The Effects of Cranberry Polyphenol Extract (CPE) Supplementation on Astringency and Flavor Perception as a Function of PROP Taster Status and Other Individual Factors

This study investigated whether PROP (6-n-propylthiouracil) taster status and other individual factors (gender, ethnicity, BMI, and age) are markers of variation in perceptions of astringency and other flavor attributes. Participants (n = 125) evaluated cranberry juice cocktail samples (CJC) supplemented with cranberry-derived polyphenol extract (CPE, added at 0, 0.3, 0.5 and 0.75 g/L), as well as control samples, unsweetened cranberry juice (CJ) and an aqueous solution of 0.75 g/L CPE. Subjects evaluated samples for key sensory attributes and overall liking using a 15 cm line scale. The data were analyzed using ANCOVA and machine learning tools (regression trees and random forest modeling) to examine if the latter approach would extract more meaningful insights about the roles of personal factors in sensory perceptions of cranberry-derived stimuli. ANCOVA revealed robust stimulus effects, but no effect of PROP taster status on astringency perception was observed. Several effects of PROP×gender, ethnicity, and other factors were observed on other sensory attributes and liking. ANCOVA and machine learning tools yielded similar findings, but regression trees provided a more visualized framework. These data show that PROP taster status has a limited role in astringency perception in complex samples and that other personal factors deserve greater focus in future research on astringency perception.

A Preliminary Study of Yeast Strain Influence on Chemical and Sensory Characteristics of Apple Cider

During the fermentation of apple juice, yeast metabolism creates complex biosynthetic pathways which produce a range of compounds responsible for the organoleptic qualities of cider. In this study, basic cider quality parameters were measured to investigate the influence of six yeast strains on cider made from three apple varieties (‘Pink Lady’, ‘Sturmer’, and ‘Bulmer’s Norman’). Measurement of pH, titratable acidity, and total phenolic content revealed that yeast can influence cider attributes, albeit variety and season dependent. Descriptive sensory analysis using a trained sensory panel was conducted on cider made from ‘Pink Lady’ apples and the same six yeast strains. The sensory panel significantly differentiated the yeast strains on the attributes of ‘fresh apple’, ‘earthy’ and ‘pear’. Identifying the variety specific influence of individual yeast strains on chemical and sensory characteristics of apple cider will provide cider makers with an enhanced understanding when choosing yeast strains.

Sensory and chemical characterization of Chinese bog bilberry wines using Check-all-that-apply method and GC-Quadrupole-MS and GC-Orbitrap-MS analyses

The sensory and chemical profiles of commercial bog bilberry (BB) wines were investigated using a multi-analytical approach. Sensory test included scaling and check-all-that-apply (CATA) method with questions on liking of BB wine. The sensory data was correlated with their volatile compound profiles determined using gas chromatography coupled with quadrupole and orbitrap mass spectrometry (GC-Quadrupole/Orbitrap-MS). In general, all BB wines were characterized with "fruity", "blueberry" and "floral" odors and "sour", "mouth puckering" and "sweet" flavors. Samples more frequently characterized as "fruity" and "floral" in CATA were preferred by the panelists (n = 93). High relative proportions of o-cymene, p-cymenene, 1-octen-3-one and 3-ethylphenol in a sample (described as "ginger" and "chili") resulted in a lower liking rating. Similarly, generally disliked sample described with "Chinese herbs" and "licorice" was characterized by compounds 3-methylpentan-1-ol, 1,1,6-trimethyl-1,2-dihydronaphthalene, and 4-vinylphenol. The data will give novel information for berry wine and beverage industry on the quality factors of BB wines linked to higher acceptance.

Phenolic compounds in Nordic berry species and their application as potential natural food preservatives

An increasing demand for natural food preservatives is raised by consumers. For Nordic berry species, abundance of phenolic compounds and potent activities of anti-oxidation and anti-bacteria enables a great potential as food preservatives. This review provides a systematic examination of current literature on phenolic profiles, anti-oxidative and anti-bacterial activities of various extracts of Nordic berry species, as well as the impact of various structure features of phenolics on the bioactivities. Special attention is placed on exploitation of leaves of berry species and pomaces after juice-pressing as side-streams of berry production and processing. The current progress and challenges in application of Nordic berry species as food preservatives are discussed. To fully explore the potential application of Nordic berry species in food industry and especially to valorize the side-streams of berry cultivation (leaves) and juice-pressing industry (pomaces), it is crucial to obtain extracts and fractions with targeted phenolic composition, which have high food preserving efficacy and minimal impact on sensory qualities of food products.

Potential of Probiotic Frozen Blackcurrant Products: Consumer Preference, Physicochemical Characterization, and Cell Viability

Blackcurrant is a healthy, affordable, and traditionally gardened berry that, thus far, has been underused in food applications. From the consumers’ point of view, the acidic taste of blackcurrants is a challenge; therefore, these berries have mainly been utilized for sugary juice production. This research study aimed to develop a frozen vegan blackcurrant product with pleasant sensory properties and potential probiotic function. A candidate probiotic, Lactoplantibacillus plantarum Q823, was used in the manufacturing process. The physicochemical properties, nutritional composition, and consumer preference for the developed product were assessed, as was the viability of L. plantarum Q823 during storage time and in an in vitro gastrointestinal model. Consumers (n = 71) perceived the developed product to be pleasant. L. plantarum Q823 had high viability counts (log colony forming units (cfu) g⁻¹ 7.0 ± 0.38) in the final product, although the viability of L. plantarum Q823 during storage time needs to be enhanced to obtain a probiotic product. Thus, within an optimized formulation, blackcurrant berries represent a potential raw material for functional frozen food products.

Chemical, Microbiological and Sensory Stability of Steam Extracted Jaboticaba (Myrciaria jaboticaba) Juice

Jaboticaba (Myrciaria jaboticaba) is a Brazilian berry rich in phenolic compounds, much appreciated for its sweet and slightly acid taste, and highly perishable. Thus, we aimed at producing jaboticaba juice by steam extraction and at investigating its microbiological, sensorial and chemical qualities during storage for up to 168 days. Juice was microbiologically safe and even though unsweetened juice was well accepted, sucrose addition further improved flavor (21%), overall impression (11%) and purchase intent (21%) scores. Cyanidin-3-O-glucoside (C3G) was the major phenolic (40%), followed by gallic (28%) and ellagic acids (21%). Total phenolics contents decreased from 27% (50 °C) to 50% (25 °C), mainly driven by C3G degradation. At 60 °C, total phenolics contents did not change after 42 days since C3G degradation was counterbalanced by gallic acid formation (129%), which followed zero-order reaction kinetics. Anthocyanins degradation followed first-order reaction kinetics (C3G half-life at 25 °C = 21.7 days) and was associated with color changes during storage. In conclusion, steam extraction followed by hot-filling technique ensured a juice with at least six months of shelf life.

Influence of the variety on the quality of organic black currant juices

The results of a comparative study of the quality of blackcurrant juices of five varieties of ARSRIFCB breeding suitable for industrial commercial use are presented: Azhurnaya, Orlovskaya Serenada, Orlovsky Vals, Ocharovanye, Chudnoye Mgnovenye. The sensory profiles of juices and their relation to scoring and varietal characteristics were studied. An analysis of the sensory qualities of mono-varietal blackcurrant juices showed that they largely depend on varietal characteristics, such as transparency and thickness, the sensation of acidity and sweetness, and the softness of the taste (absence of harsh acid in the taste). The indicators of the point analysis confirm the results of the descriptor. Sensory analysis data (point and descriptor) showed that preference is given to products with a ruby-red color, typical for blackcurrant juices, bright, not cloudy. Among the studied varieties, of great interest for juice production are the varieties Ocharovanye and Azhurnaya.

An overview of the perception and mitigation of astringency associated with phenolic compounds

Astringency, as a kind of puckering, drying, or rough sensation, is widely perceived from natural foods, especially plants rich in phenolic compounds. Although the interaction and precipitation of salivary proteins by phenolic compounds was often believed as the major mechanism of astringency, a definitive theory about astringency is still lacking due to the complex oral sensations. The interaction with oral epithelial cells and the activation of trigeminal chemoreceptors and mechanoreceptors also shed light on some of the phenolic astringency mechanisms, which complement the insufficient mechanism of interaction with salivary proteins. Since phenolic compounds with different types and structures show different astringency thresholds in a certain regularity, there might be some relationships between the phenolic structures and perceived astringency. On the other hand, novel approaches to reducing the unfavorable perception of phenolic astringency have been increasingly emerging; however, the according summary is still sparse. Therefore, this review aims to: (a) illustrate the possible mechanisms of astringency elicited by phenolic compounds, (b) reveal the possible relationships between phenolic structures and perception of astringency, and (c) summarize the emerging mitigation approaches to astringency triggered by phenolic compounds. This comprehensive review would be of great value to both the understanding of phenolic astringency and the finding of appropriate mitigation approaches to phenolic astringency in future research.

Impact of lactic acid fermentation on sensory and chemical quality of dairy analogues prepared from lupine (Lupinus angustifolius L.) seeds

Lupine (Lupinus sp.) is a valuable source of plant proteins. There is little knowledge on the impact of food processing on composition and sensory properties of lupine products. In this research, we investigated the impact of fermentation with five starters of lactic acid bacteria on the sensory quality and flavor-active compounds in dairy analogues prepared from sweet lupine (Lupinus angustifolius L.). The sensory qualities of unfermented and fermented products were studied with generic descriptive analysis and affective tests. Acids and sugars were analyzed with GC-FID and volatiles with HS-SPME-GC-MS and GC-O. Fermentation increased sourness and 'vinegar' odor and reduced the 'beany' odor and flavor as well as the unpleasantness of flavor. Formation of volatiles during the fermentation was dependent on the starters. However, all fermentations increased the contents of lactic, acetic, and hexanoic acids, while reducing the contents of hexanal, described as 'grassy' in the unfermented lupine sample.

Effect of Saccharomyces cerevisiae and Schizosaccharomyces pombe strains on chemical composition and sensory quality of ciders made from Finnish apple cultivars

Composition of volatile compounds and concentrations of sugars and organic acids were studied in apple ciders produced with Saccharomyces cerevisiae and Schizosaccharomyces pombe yeasts using eleven different Finnish apple cultivars. Moreover, sensory quality of selected ciders was studied using check-all-that-apply test with untrained panelists. Seventy-seven volatile compounds were detected in the samples using HS-SPME-GC-MS. In general, the ciders had higher concentrations of higher alcohols, aldehydes, and acetals whereas the juices contained higher contents of C6-alcohols. Simultaneously, fermentation using S. pombe resulted in lower concentrations of malic acid, ethyl pentanoate, ethyl hexanoate, and volatile acids and higher concentrations of residual sugars compared to S. cerevisiae. Ciders made using S. cerevisiae were characterized as 'alcoholic' and 'yeasty' while S. pombe ciders were more frequently described as 'sweet', 'honey-like', and less rated as sour. Besides the strong effect by the yeasts, apple cultivars had significant effects on the compositional and sensorial properties of apple ciders.

Enhancement of Biological Properties of Blackcurrants by Lactic Acid Fermentation and Incorporation into Yogurt: A Review

Blackcurrants (BC) and yogurt are known to possess several health benefits. The objective of this review was to compile the latest information on the effect of lactic acid fermentation on BC and their incorporation into yogurt, including the impact of this combination on chemical composition, sensory aspects, and health attributes of the blend. Google Scholar, Scopus, and PubMed were used to research the most recent literature on BC juice, the whole BC berry, and yogurt. Health benefits were assessed from human and animal studies within the last 5 years. The results suggest that BC have several health promoting compounds that ameliorate some neurological disorders and improve exercise recovery. Yogurt contains compounds that can be used to manage diseases such as type 2 diabetes (T2D) and irritable bowel disease (IBD). Fermenting BC with lactic acid bacteria (LAB) and its incorporation into yogurt products increases the polyphenol and antioxidant capacity of BC, creating a blend of prebiotics and probiotics compounds with enhanced benefits. More research is needed in the area of lactic acid fermentation of berries in general, especially BC.

Blackcurrant (Ribes nigrum) lowers sugar-induced postprandial glycaemia independently and in a product with fermented quinoa: a randomised crossover trial

Berries rich in anthocyanins have beneficial effects on postprandial glycaemia. We investigated whether blackcurrant (75 g in a portion) independently and in a product with fermented quinoa induced similar effects on the sugar-induced postprandial glucose metabolism as observed before with 150 g of blackcurrant. Twenty-six healthy subjects (twenty-two females and four males) consumed four test products after fasting overnight in a randomised, controlled crossover design. Each test product portion contained 31 g of available carbohydrates and had similar composition of sugar components: 300 ml water with sucrose, glucose and fructose (SW; reference), blackcurrant purée with added sugars (BC), a product consisting of the blackcurrant purée and a product base with fermented quinoa (BCP) and the product base without blackcurrant (PB). Blood samples were collected at 0, 15, 30, 45, 60, 90, 120 and 180 min after eating each test product to analyse the concentrations of glucose, insulin and NEFA. In comparison with the SW, the intake of both the BC and BCP resulted in reduced glucose and insulin concentrations during the first 30 min, a more balanced decline during the first hour and improved glycaemic profile. The BCP induced more efficient effects than the BC due to the product base with fermented quinoa. A rebound of NEFA after the sugar-induced hypoglycaemic response was attenuated at the late postprandial phase by the BC and BCP. In conclusion, we showed that 75 g of blackcurrant and the product with fermented quinoa were able to lower postprandial glycaemia and insulinaemia.

Influence of enzymatic treatment on the chemical composition of lingonberry (Vaccinium vitis-idaea) juice

The effects of different enzymes, their dosages, and incubation times on juice yield and chemical composition of lingonberry juice were assessed. Nonvolatile composition including sugars, acids and phenolic compounds (anthocyanins, hydroxycinnamic acids, flavonols and flavan-3-ols) was analyzed using GC-FID, LC-DAD and LC-MS methods, whereas the volatile compound profile was examined using HS-SPME-GC-MS. Selection of the enzyme had a significant effect on the juice yield by increasing it from 70% without enzyme treatment up to 81%. Enzymes significantly increased the contents of most of the phenolic compounds in the juices but had little impact on the contents of sugars and acids. Heat treatment without enzyme addition also significantly affected the composition. Generally, increasing incubation time increased the contents of various phenolic compounds, especially flavan-3-ols and hydroxycinnamic acids, whereas the effects of dosage were mostly negligible. Enzyme treatment increased the contents of volatile compounds, regardless of dosage or incubation time.

Impact of storage on sensory quality of blackcurrant juices prepared with or without enzymatic treatment at industrial scale

Blackcurrant juices prepared with or without enzyme treatment at industrial scale were stored at room temperature or + 4 °C for 1 year, and their sensory profiles, chemical composition and rheological properties were investigated. The juice without enzyme treatment had less intense colour and it was perceived and measured as more viscose than the juice produced with enzyme assistance. Content of monomeric anthocyanins decreased significantly during storage in both juice types under both storing conditions. However, changes in colour intensity were observed only in the non-enzymatic juices. In the discrimination tests based on the appearance, the stored samples were detected as significantly different. Storage resulted in significant changes in contents of hydroxycinnamic acids and flavonols, but this did not have an impact on the bitterness or astringency of the juices. Moreover, sugar and acid contents were mainly unchanged during storage. Storage resulted in a decrease in dynamic viscosity and greater differences in viscoelastic properties for the juice with enzymatic assistance. This study provides important information about the stability of juices typically stored at room temperature for a long time.

Assessment of chemical composition and sensorial properties of ciders fermented with different non-Saccharomyces yeasts in pure and mixed fermentations

This work presents the attempt to enhance the flavor complexity of cider fermented by different non-Saccharomyces species. Pichia kluyveri and Hanseniaspora vineae pure cultures were used as reference ciders. Mixed cultures between all 4 species gave 5 fermentations, where Hanseniaspora uvarum or Torulaspora quercuum were included for apple juice fermentation. Chemical composition and sensorial properties of all ciders were studied. The results indicated that the growth of P. kluyveri and H. vineae were interreacted and also affected by H. uvarum and T. quercuum. H. vineae was more capable of consuming sugar than P. kluyveri. Ciders from the single culture fermentation with P. kluyveri (Pk), as well as from mixed fermentation with P. kluyveri and H. uvarum (Pk-Hu), had high residual sugar, sugar/acid ratio, and glucose-fructose consumption ratio. Large shifts in the consumption and production of organic acids and polyphenols among all ciders were observed. The calculation of the relative odor activity value (rOAV) showed that 17 volatile compounds had an rOAV >1 in at least one sample, and acetate esters and ethyl esters were the groups with the highest number of volatile compounds of importance to the cider aroma. Among these 17 compounds, 3-methylbutyl acetate, 2-methylbutyl acetate, ethyl hexanoate, ethyl octanoate, and β-damascenone exhibited high rOAVs in some ciders and might contribute fruity, floral, and sweet features to the cider aroma. Besides, the tropical fruity aroma from 3-methylbutyl acetate was only perceived in Pk and Pk-Hu. The partial least squares regression (PLSR) analysis revealed that acetate esters contributed positively to the roasted and cooked odor of all ciders. This is the first study evaluating simultaneous fermentation of two non-Saccharomyces yeasts to produce cider, which provides new insights into cider production.

Compositional Diversity among Blackcurrant ( Ribes nigrum) Cultivars Originating from European Countries

Berries representing 21 cultivars of blackcurrant were analyzed using liquid chromatographic, gas chromatographic, and mass spectrometric methods coupled with multivariate models. This study pinpointed compositional variation among cultivars of different origins cultivated in the same location during two seasons. The chemical profiles of blackcurrants varied significantly among cultivars and growing years. The key differences among cultivars of Scottish, Lithuanian, and Finnish origins were in the contents of phenolic acids (23 vs 16 vs 19 mg/100 g on average, respectively), mainly as 5- O-caffeoylquinic acid, 4- O-coumaroylglucose, ( E)-coumaroyloxymethylene-glucopyranosyloxy-( Z)-butenenitrile, and 1- O-feruloylglucose. The Scottish cultivars were grouped on the basis of the 3- O-glycosides of delphinidin and cyanidin, as were the Lithuanian cultivars. Among the Finnish samples, the content of myricetin 3- O-glycosides, 4- O-caffeoylglucose, 1- O-coumaroylglucose, and 4- O-coumaroylglucose were significantly different between the two green-fruited cultivars and the black-fruited cultivars. The samples from the studied years differed in the content of phenolic acid derivatives, quercetin glycosides, monosaccharides, and citric acid.

Molecular Controls of Proanthocyanidin Synthesis and Structure: Prospects for Genetic Engineering in Crop Plants

Proanthocyanidins (PAs) are widespread oligomeric and polymeric flavan-3-ols with significant benefits to human and animal health. As products of the general flavonoid pathway, the biosynthesis of the flavan-3-ols is well-understood and the major enzyme-encoding genes that determine PA structure have been identified. However, the mechanism of PA polymerization remains unknown. The most important transcription factors regulating PA biosynthesis are the MYB factors, potent tools for enhancing PA biosynthesis in plants. In some species, simple overexpression of these transcription factors has led to spectacular successes in upregulating PA synthesis. However, targeted metabolic engineering of the PA structure has not yet been achieved.

Red/Green Currant and Sea Buckthorn Berry Press Residues as Potential Sources of Antioxidants for Food Use

The potential for using extracts of press residues from black, green, red, and white currants and from sea buckthorn berries as sources of antioxidants for foods use was investigated. Press residues were extracted with ethanol in four consecutive extractions, and total Folin-Ciocalteu (F-C) reactive material and authentic phenolic compounds were determined. Radical quenching capability and mechanisms were determined from total peroxyl radical-trapping antioxidant capacity (TRAP) and oxygen radical absorbance capacity (ORAC) assays and from diphenylpicrylhydrazyl (DPPH) kinetics, respectively; specific activities were normalized to F-C reactive concentrations. Levels of total F-C reactive materials in press residue extracts were higher than in many fruits and showed significant radical quenching activity. Black currant had the highest authentic phenol content and ORAC, TRAP, and DPPH reactivity. Sea buckthorn grown in northern Finland showed extremely high total specific DPPH reactivity. These results suggest that berry press residues offer attractive value-added products that can provide antioxidants for use in stabilizing and fortifying foods.

Phytochemical analysis of salal berry (Gaultheria shallon Pursh.), a traditionally-consumed fruit from western North America with exceptionally high proanthocyanidin content

Salal (Gaultheria shallon Pursh.) is a wild perennial shrub of the Ericaceae and common in coastal forests of western North America, and its berries were an important traditional food for First Nations in British Columbia. Salal berries were investigated for phytochemical content and antioxidant capacity over the course of fruit development. The proanthocyanidin content was extremely high in young berries (280.7 mg/g dry wt) but dropped during development to 52.8 mg/g dry wt. By contrast, anthocyanins accumulated only at the late berry stages. Total antioxidant capacity, as measured by the 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) method, reflected both proanthocyanidin and anthocyanin content, and in mature berries reached 36 mmol Trolox equivalents/100 g dry wt. More detailed phytochemical analysis determined that delphinidin 3-O-galactoside is the dominant anthocyanin, and that the berries are also rich in procyanidins, including procyanidin A2 which has been implicated in anti-adhesion activity for uropathogenic E. coli. Proanthocyanidins were 60% prodelphinidin, and overall concentrations were higher than reported for many Vaccinium species including blueberry, lingonberry, and cranberry. Overall, the phenolic profile of salal berries indicates that these fruit contain a diversity of health-promoting phenolics.

Jabuticaba (Myrciaria jaboticaba) juice obtained by steam-extraction: phenolic compound profile, antioxidant capacity, microbiological stability, and sensory acceptability

Jabuticaba (Myrciaria jaboticaba) is a dark-colored fruit native to Brazil that has a desirable flavor and high anthocyanin content. In the present study, jabuticaba juice was produced by steam-extraction and the phenolic compound profile, antioxidant capacity, instrumental color, and microbiological quality were evaluated during 90 days of storage at 25 °C. Cyanidin-3-O-glucoside represented 45% of the total phenolic content of the juice, which reduced with extent of 80% during storage. Total phenolic content of the juice increased by 59% during 90 days of storage, which entailed, average 4.4-fold increase in the content of gallic and ellagic acids. FRAP assay was most sensitive for measuring gallic and ellagic acids, while the TEAC assay was the most sensitive for measuring anthocyanins. Although [Formula: see text] and [Formula: see text] values of jabuticaba juice decreased and [Formula: see text] increased during storage. Jabuticaba juice remained microbiologically stable during storage, and did not support the growth of inoculated Escherichia coli and Salmonella enteritidis, suggesting antimicrobial activity.

Role of Flavonols and Proanthocyanidins in the Sensory Quality of Sea Buckthorn (Hippophaë rhamnoides L.) Berries

Sensory profile, flavonols, proanthocyanidins, sugars, and organic acids were investigated in purees of six sea buckthorn (Hippophaë rhamnoides) cultivars. The sensory profiles of the purees were dominated by intense sourness followed by astringency and bitterness due to the high content of malic acid. Malic acid and isorhamnetin glycosides, especially isorhamnetin-3-O-sophoroside-7-O-rhamnoside, had close association with the astringent attributes in the different purees, whereas some of the known astringent compounds such as proanthocyanidin dimers and trimers or quercetin glycosides, had less impact. Moreover, the ratios between contents of acids and phenolic compounds were more important predictors of bitterness than the individual variables alone. Astringency and bitterness are important sensory factors for the consumer acceptance of sea buckthorn products. The current study provides new knowledge on the correlations between sensory properties and composition and supports industrial utilization of the sea buckthorn berries.

Effect of processing technologies and storage conditions on stability of black currant juices with special focus on phenolic compounds and sensory properties

Juice was pressed from black currants without enzyme treatment (NEB=Non-Enzymatic Berry) followed by re-pressing of the residue with enzymes (EPR=Enzymatic Press Residue) and the results were compared to the conventional enzyme-aided berry pressing (EB=Enzymatic Berry). EPR-juice had 9- and 5-fold higher contents of phenolic compounds compared with the NEB- and EB-juices, respectively. Effect of the low content and stability of phenolics was noticed as loss of the visual color in the NEB-juice during storage. The decrease in monomeric anthocyanins and the increase in phenolic acids were most severe in the NEB-juice, whereas the most significant decline in hydroxycinnamic acid derivatives occurred in the enzyme-treated juices. Storage in light induced less change in the phenolic composition in EPR-juice than in the two other juices. The study gave new knowledge on changes in individual metabolites, in sensory properties and in the shelf life of berry juices.

Influence of juice processing factors on quality of black chokeberry pomace as a future resource for colour extraction

Aronia melanocarpa berries are a rich source of anthocyanins and its pomace, a by-product of juice processing, could be efficiently used for extraction of natural colours for the food industry. This study evaluated the influence blanching, freezing, maceration temperatures (2°C, 50°C) and enzyme treatments before juice pressing on the yield and anthocyanin composition of both juice and pomace. Total anthocyanin levels in pomace were affected mostly by enzyme treatment followed by maceration temperature. The pre-heating of the mash prior to processing increased juice yield and retention of anthocyanins in the pomace. Cold maceration of frozen berries without enzyme addition gave the highest concentrations of anthocyanins in the pomace, and both cold and hot maceration of fresh unblanched berries with enzyme the lowest. The results support future exploitation of natural colours from pomace side streams of Aronia, thus increasing competitiveness of Aronia berry production.

Characterizing and improving the sensory and hedonic responses to polyphenol-rich aronia berry juice

Interest in nutrient-rich berry juices is growing, but their high polyphenol levels render them sensorily unappealing. Fifty adults, who were assessed for sensory phenotype and dietary behaviors, provided sensory and palatability ratings of juices from 'Viking' aronia berries for each of seven harvest weeks. By peak harvest, juice preference increased two-fold, averaging neither like/dislike. This hedonic shift was associated with: increases in juice sugars paralleling increases in perceived sweetness (maximum = weak); reductions in percent acidity paralleling reductions in sourness (minimum = moderate), astringency (minimum = to just above weak) and bitterness (minimum = just below weak). About 25% of adults liked the aronia juice, including adults who also liked an aqueous citric acid solution (average rating = moderately sour) or those who reported adventurous eating behaviors. Bitter taste phenotype, measured by propylthiouracil or quinine bitterness, failed to explain significant variation in juice sensation or preference. We also collected sensory and preference ratings from juice collected at peak harvest blended with sugar and/or sweet olfactory flavoring (10 ppm ethyl butyrate). Increasing juice sweetness by adding 5% sucrose decreased sourness and improved preference from weak dislike to weak like. Adding sweet olfactory flavoring decreased juice sourness without changing preference. Adding sweet flavoring and 3% sucrose resulted in reduction of sourness and improvements in preference ratings comparable to 5% added sucrose. Neither added sugar nor flavoring blocked juice astringency. In summary, these findings suggest that aronia juice, even from berries picked at peak harvest, appealed to only a few adults (sour likers or adventurous eaters). Although enhanced sweetness, with added sugar and sweet olfactory flavoring, improved aronia juice preference, broader sensory approaches are required to blunt astringency for greater consumer appeal.

Stability of Hydroxycinnamic Acid Derivatives, Flavonol Glycosides, and Anthocyanins in Black Currant Juice

The stability of phenolic compounds was followed in black currant juice at ambient temperatures (in light and in dark conditions) and at +4 °C for a year. Analyses were based on high-performance liquid chromatography-diode-array detection-electrospray ionization-mass spectrometry (or tandem mass spectrometry) and high-performance liquid chromatography-diode-array detection-electrospray ionization-quadrupole time-of-flight mass spectrometry methods supported by nuclear magnetic resonance after selective high-performance liquid chromatography isolation. Altogether, 43 metabolites were identified, of which 2-(Z)-p-coumaroyloxymethylene-4-β-d-glucopyranosyloxy-2-(Z)-butenenitrile, 2-(E)-caffeoyloxymethylene-4-β-d-glucopyranosyloxy-2-(Z)-butenenitrile, 1-O-(Z)-p-coumaroyl-β-d-glucopyranose, (Z)-p-coumaric acid 4-O-β-d-glucopyranoside, and (Z)-p-coumaric acid were novel findings in black currant juice. Hydroxycinnamic acid derivatives degraded 20-40% at room temperature during one year of storage, releasing free hydroxycinnamic acids. O-Glucosides of hydroxycinnamic acid compounds were the most stable, followed by O-acylquinic acids, acyloxymethyleneglucosyloxybutenenitriles, and O-acylglucoses. Light induced the isomerization of (E)-coumaric acid compounds into corresponding Z-isomers. Flavonol glycosides stayed fairly stable. Flavonol aglycones were derived mainly from malonylglucosides. Over 90% of anthocyanins were lost at room temperature in a year, practically independent of light. Storage at low temperatures, preferably excluding light, is necessary to retain the original composition of phenolic compounds.

Influence of Controlled Postflowering Temperature and Daylength on Individual Phenolic Compounds in Four Black Currant Cultivars

The effects of postflowering temperature and daylength on the concentration of individual phenolic compounds were studied in black currant (Ribes nigrum L.) berries under controlled phytotron conditions. The four cultivars studied varied greatly in their concentrations of individual phenolic compounds and temperature stability for accumulation. The concentrations of a wide range of identified phenolic compounds were strongly influenced by temperature over the 12-24 °C range, often with opposite temperature gradient patterns for compounds within the same subclass. Accumulation of anthocyanins and flavonols increased under natural long day conditions, which provided an increased daily light integral, while under identical light energy conditions, photoperiod had little or no effect on the concentration of phenolic compounds. Furthermore, with the exception of members of the hydroxycinnamic acid subclass, the concentration of most phenolic compounds was higher in berries ripened outdoors than in the phytotron, apparently due to screening of UV-B radiation by the glass cover.

Flavonol glycosides in berries of two major subspecies of sea buckthorn (Hippophaë rhamnoides L.) and influence of growth sites

Flavonol glycosides of wild sea buckthorn (Hippophaë rhamnoides ssp. sinensis) berries from China and cultivated berries (H. rhamnoides ssp. mongolica) from Finland and Canada were identified and quantified. Twenty-six flavonol glycosides were found with isorhamnetin and quercetin as the major aglycones. The contents of flavonol glycosides ranged 23-250 mg/100 g fresh berries and were significantly higher in the berries of ssp. sinensis than in those of ssp. mongolica. Among the cultivars of ssp. mongolica, the berries of 'Oranzhevaya' had the lowest (23 mg/100 g) content, and those of 'Prevoshodnaya' the highest content of flavonol glycosides (80 mg/100 g). Within the ssp. mongolica, the samples from Kittilä (Northern Finland) had higher levels of most flavonol glycosides than those from Turku (Southern Finland) and Québec. Among the ssp. sinensis berries of different growth sites, increasing trends were detected in the contents of most of the compounds as the altitude increased and as the latitude decreased. The wild berries (ssp. sinensis) from Sichuan had remarkably high contents and unique profiles of flavonol glycosides.

Proanthocyanidins and Their Contribution to Sensory Attributes of Black Currant Juices

Black currant juices from five different cultivars were analyzed for composition, content, and mean degree of polymerization (mDP) of proanthocyanidins (PA) by UPLC-MS/MS. Juices contained both procyanidins (PC) and prodelphinidins (PD), but the PC-% varied significantly, from 28 to 82% of the total PA. In addition, high PD-% was related to high mDP and total PA content. Enzyme-assisted processing increased significantly total PA (5-14-fold), PD-% (12-65%), and mDP (1.8-6.2-fold) in the juices of all cultivars. Enzymatic treatment increased the contents of large PAs more than those of small PAs. The contents of PA and mDP were positively associated with the mouth-drying and puckering astringent characteristics. However, the PA content did not contribute to the bitter taste. Juices from the most bitter cultivars had the lowest contents of proanthocyanidins regardless of the processing method. This finding indicates the existence of other bitter compounds in black currants in addition to PA.

Nontargeted metabolite profiles and sensory properties of strawberry cultivars grown both organically and conventionally

Strawberry (Fragaria × ananassa Duch.) contains many secondary metabolites potentially beneficial for human health, and several of these compounds contribute to strawberry sensory properties, as well. In this study, three strawberry cultivars grown both conventionally and organically were subjected to nontargeted metabolite profiling analysis with LC-qTOF-ESI-MS and to descriptive sensory evaluation by a trained panel. Combined metabolome and sensory data (PLS model) revealed that 79% variation in the metabolome explained 88% variation in the sensory profiles. Flavonoids and condensed and hydrolyzable tannins determined the orosensory properties, and fatty acids contributed to the odor attributes of strawberry. Overall, the results indicated that the chemical composition and sensory quality of strawberries grown in different cultivation systems vary mostly according to cultivar. Organic farming practices may enhance the accumulation of some plant metabolites in specific strawberry genotypes. Careful cultivar selection is a key factor for the improvement of nutritional quality and marketing value of organic strawberries.

Flavonol glycosides and other phenolic compounds in buds and leaves of different varieties of black currant (Ribes nigrum L.) and changes during growing season

Phenolic compounds in buds and leaves of three varieties of black currant in Finland were identified by HPLC-DAD-ESI-MS/MS. Forty-three phenolic compounds of flavonol glycosides, proanthocyanidins and phenolic acids were found in variety "Mikael" whereas only thirty-five in "Mortti" and "Jaloste n:o 15". Glycosides of quercetin and kaempferol were the major phenolics. Rutin, hyperoside, isoquercitrin, kaempferol-3-O-rutinoise, kaempferol-3-O-glucoside, quercetin-3-O-(6″-malonyl)-glucoside and a kaempferol-malonylhexoside were the most abundant flavonol glycosides. The contents of flavonol glycosides ranged from 1 to 7 mg/g fresh weight in leaves showing typically an increasing trend from July to August, reaching the highest values in early October in "Mikael" and the end of August in "Mortti" and "Jaloste n:o 15". This is the first systematic report of the composition and content of phenolic compounds in buds and leaves of black currant.

Phenols and ascorbic acid in black currants (Ribes nigrum L.): variation due to genotype, location, and year

Black currant berries contain many biochemical compounds with proven or potential human health benefits. We studied the content of total and single polyphenols, ascorbic acid, soluble sugars, and titratable acidity for two advanced selections and three cultivars of black currant at two distant locations in Sweden (south: 56°06'N; north: 65°21'N) over a 3 year period. Regression analyses revealed the effect of genotype to be considerably larger than that of location and year. However, significant effects of location, year, and interactions were also revealed. A principal component analysis nevertheless separated the genotypes. The content of ascorbic acid, total phenols, total anthocyanins, and soluble sugars was highest in berries from the south, whereas the content of phenolic acids and titratable acidity was highest in berries from the north. The results show that selection of cultivars and production sites are important for cultivation of high-quality black currant raw material for health-promoting products.

Effects of latitude and weather conditions on phenolic compounds in currant (Ribes spp.) cultivars

Effects of growth latitude and weather conditions on phenolic compounds of currants (Ribes spp.) were investigated. The berries of red currant cultivar 'Red Dutch', white currant 'White Dutch', and green currant 'Vertti' were collected in seven consecutive years from two growth sites (south and north) with a latitudinal distance of 690 km. The contents of hydroxycinnamic acid conjugates and flavonol glycosides in 'Vertti' were higher than those in 'White Dutch' by 8 and 5 times, respectively, and by 50 and 3 times than those in 'Red Dutch', respectively. The total content of phenolic compounds was 10-19% higher in the north than in the south (p < 0.05). In 'Red Dutch', anthocyanins were 12% richer in berries from the north compared with those from the south (p < 0.05). The total content of hydroxycinnamic acid conjugates in 'Vertti' and 'White Dutch' from the north was 30% higher than those from the south (p < 0.05). High radiation and temperature were associated with low contents of the major phenolic compounds in all the cultivars studied. High humidity correlated with low levels of hydroxycinnamic acid conjugates in green and white currants.