Composition of Sugars, Organic Acids, Phenolic Compounds, and Volatile Organic Compounds in Lingonberries (Vaccinium vitis-idaea L.) at Five Ripening Stages.

Wild lingonberries are a traditional source of food in the Nordic countries and an important contributor to economic activity of non-wood forest products in the region. Lingonberries are a rich source of bioactive compounds and can be a valuable contributor to a healthy diet. However, there are few studies available on how the bioactive compounds in lingonberries develop as they ripen. In this investigation, we examined the content of 27 phenolic compounds, three sugars, four organic acids, and 71 volatile organic compounds at five ripening stages. The study showed that, while the highest content of phenolic compounds was found early in the development, the organoleptic quality of the fruits improved as they ripened. From the first to the last stage of development, anthocyanins went from being nearly absent to 100 mg/100 g fw, and there was an increased content of sugars from 2.7 to 7.2 g/100 g fw, whereas the content of organic acids decreased from 4.9 to 2.7 g/100 g fw, and there were several changes in the profile of volatiles. The contents of flavonols, cinnamic acid derivatives, flavan-3-ols, and the total concentration of phenolic compounds were significantly lower in the fully ripe berries compared to berries in the early green stage. In addition to the changes occurring due to ripening, there was observed variation in the profile of both phenolic compounds and volatiles, depending on the growth location of the berries. The present data are useful for the assessment of harvest time to obtain the desired quality of lingonberries.

Exploring the Sensory Properties and Preferences of Fruit Wines Based on an Online Survey and Partial Projective Mapping.

Non-grapefruits with unique sensory properties and potential health benefits provide added value to fruit wine production. This study aimed to explore consumers' fruit wine preferences and descriptors for the varied fruit wines. First, 234 consumers participated in an online survey concerning their preferences for different wines (grape, blueberry, hawthorn, goji, Rosa roxburghii, and apricot). In addition, their attitudes towards general health interests, food neophobia, alcoholic drinks, and sweetness were collected. Grape wine and blueberry wine were the most favored wines, and goji wine was the least liked fruit wine sample. Moreover, 89 consumers were invited to evaluate 10 commercial fruit wines by using partial projective mapping based on appearance, aroma, and flavor (including taste and mouthfeel) to obtain a comprehensive sensory characterization. Multifactor analysis results showed that consumers could differentiate the fruit wines. Participants preferred fruit wines with "sweet", "sour", and "balanced fragrance", whereas "bitter", "astringent", "deep appearance", and "medicinal fragrance" were not preferred. Attitudes toward health, food neophobia, alcohol, and sweetness had less influence than taste and aroma (sensory attributes) on the preferences for fruit wine products. More frequent self-reported wine usage resulted in higher consumption frequency and liking ratings compared to non-users. Overall, the main factors influencing consumer preference for fruit wines were the sensory characteristics of the products, especially the taste.

Influence of different Lachancea thermotolerans strains in the wine profile in the era of climate challenge.

The study performed sequential fermentations of red grape juice using several strains of Lachancea thermotolerans and one strain of Saccharomyces cerevisiae. Due to the new conditions imposed by climate change, wine acidity must be affected as well as the volatile profile. Non-Saccharomyces yeasts such as L. thermotolerans are real alternatives to soften the impact of climate change in winemaking. The L. thermotolerans strains included three commercially available strains and two wine-related natural isolates. L. thermotolerans showed significant statistical differences in basic chemical parameters such as lactic acid, malic acid, or ethanol concentrations as well as in the volatile profile. S. cerevisiae clearly produced some volatile compounds in higher amounts than the studied L. thermotolerans strains while others showed the opposite effect. Sequential fermentations involving any of the studied strains of L. thermotolerans with S. cerevisiae showed an increased volatile profile compared to the S. ceresisiae single fermentation, highlighting the synergic effect between the studied species.

Comparison of volatile compounds and sensory profiles of alcoholic black currant (Ribes nigrum) beverages produced with Saccharomyces, Torulaspora, and Metschnikowia yeasts.

Black currants (Ribes nigrum) were fermented with Saccharomyces and non-Saccharomyces yeasts without added sugar to yield low-ethanol-content beverages. The effects of yeasts on the volatile compounds and sensory characteristics were analysed by HS-SPME-GC-MS, GC-O, and generic descriptive analysis. Ninety-eight volatile compounds were identified from the black currant juice and fermented beverages. Significant increases in the contents of esters (131 %), higher alcohols (391 %), and fatty acids (not present in juice sample) compared to initial juice were observed depending on the yeasts used. GC-O analysis revealed the higher impact of esters on the sensory properties of Saccharomyces bayanus-fermented beverage compared to the Torulaspora delbrueckii-fermented beverage. In the sensory evaluation, non-Saccharomyces yeasts resulted in a higher 'black currant odour'. However, all beverages were intensely sour, which can be a significant challenge in the development of alcoholic berry beverages.

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.

Phenolic Compound Profiles in Alcoholic Black Currant Beverages Produced by Fermentation with Saccharomyces and Non-Saccharomyces Yeasts.

Alcoholic beverages with low ethanol contents were produced by fermenting black currant juice with Saccharomyces and non-Saccharomyces yeasts without added sugar. The effects of different yeasts on the phenolic compounds (anthocyanins, hydroxycinnamic acids, flavonols, and flavan-3-ols) and other selected constituents (the ethanol content, residual sugars, organic acids, and color) of the black currants were assessed. Single yeast-fermented beverages had higher ethanol contents (3.84-4.47%, v/v) than those produced by sequential fermentation. In general, the fermentation of black currant juice increased the contents of organic acids and flavonols, whereas anthocyanin contents decreased. All of the fermentations decreased the contents of glycosylated nitrile-containing hydroxycinnamic acids, resulting in higher contents of the corresponding aglycons. Fermentation with Saccharomyces bayanus resulted in lower anthocyanin and organic acid contents compared to the other yeasts. Sequential fermentations with Saccharomyces cerevisiae and Metschnikowia pulcherrima led to the highest total hydroxycinnamic acids and anthocyanins among all of the fermentations.