Prevention of quercetin precipitation in red wines: a promising enzymatic solution

Flavonols are known for causing undesirable deposits in both red and white wines. Among flavonols, quercetin is widely considered the principal factor determining this phenomenon. One of the most accredited hypotheses claims that glycosylated derivatives of quercetin undergo hydrolysis of the glycosylic bond during the fermentation and the wine ageing, releasing quercetin aglycone, which is much less soluble in water solution and causes the precipitation. Our work describes the dynamics of quercetin-derived deposition in Chianti wines and purposes a new method, based on the enzymatic quercetin glycoside hydrolysis of the glycosidic bond, to prevent the unpleasant deposit formation during the wine ageing. In our study, forty-four monovarietal wines obtained from 7 different Italian grape varieties were compared in the content of total quercetin-3-glycosides (rutin, quercetin-3-glucuronide, quercetin-3-glucoside) and quercetin aglycone. The data confirmed the literature revealing Sangiovese as the richest in quercetin. We tested then, in a Sangiovese wine, four fining agents (PVPP, PVPP/PVI, bentonite and a vegetal protein) for quercetin removal, showing that only the PVPP had a modest aglycone removal activity. Then, the kinetics of deposit formation was studied in three Chianti wines which differed in the initial content of quercetin aglycone. This investigation highlighted that the chemical equilibrium of quercetin changes over time as the turbidity slowly increases, as previously documented. The comparison of the three dynamics also permitted us to conclude that different wines show a different ability to keep in solution quercetin. Finally, a new approach for deposit prevention was studied by a precocious Chianti wine treatment with a pectolytic enzyme having secondary glycosidase activity. This enzyme significantly accelerated the hydrolysis of glycosylated quercetins into their aglycone, which could enhance the deposition before bottling, without serious wine colour depletion. Our study represents the first evidence of the promising potential of using the pectolytic enzyme with secondary glycosidase activity to prevent quercetin deposit during Chianti ageing, in a way that is compatible with organic wine production.

Insights into the organic labelling effect: the special case of wine

PurposeWhile research shows that organic labels are perceived positively for most food products, the findings are more ambiguous for wine. This may be due to the complexity of the product. Accordingly, the labelling effect might be influenced by people's prior knowledge of wines and their attitudes towards organic wines and thus be more pronounced for certain consumer groups. Providing insights into those moderators could help to steer people towards sustainable wine consumption. Therefore, this paper aims to investigate the effect of organic labelling on consumers' liking of, and their willingness to pay (WTP) for white wine, and the role of potential moderators.Design/methodology/approachA wine tasting experiment was conducted using a within-subjects design (n = 214). The mediating role of expected liking and the moderating roles of subjective knowledge and attitude towards organic wine were analysed using the MEMORE macro in SPSS.FindingsThe results do not confirm an overall positive halo effect of labelling on liking of organic wine. Nevertheless, a positive halo effect on actual liking was observed for those respondents who have a positive attitude towards organic wine. Furthermore, an overall positive effect of organic labelling on WTP was found. Mediation effects could not be confirmed.Originality/valueThis study used an experimental design that considers not only expected liking but also actual liking and WTP for organic wines. Using a moderation-mediation framework helps to better understand consumers' quality evaluation and WTP for organic wine. Finally, it could be shown that the organic halo is more complex for the product category of wine than others have previously stated.

Motivation factors for organic wines. An analysis from the perspective of German producers and retailers

This study investigates the motives for producers that inform decisions to convert or not convert to organic wine production as well as the motives for retailers to offer or not offer organic wine and promotion of organic wine from producers’ and retailers’ perspectives. In total, 100 semi-structured in-depth interviews with 25 different types of retailers, 50 organic wineries and 25 non-organic wineries were conducted and analysed using content analysis and grounded theory. Additionally, the wine offers of 25 stores were analysed to develop an understanding of the distribution and promotion of organic wines. Producers choose to switch or not to switch to organic farming for primarily altruistic reasons. Because organic wine producers do not specifically focus on the organic nature of their wines in their communications, this attribute is typically disregarded by retailers and consumers during their wine-buying decisions, which undermines the growing demand for organic wine. There are significant differences between wine-growing regions in Germany and their vine cultivation conditions due to weather, the steepness of slopes and the attitudes towards converting conventional wine production to organic wine production. Missing knowledge and a low demand for organic wines are barriers for retailers to focus on organic wine. To our knowledge, this is the first study to investigate organic wines from numerous producers in every wine-growing region in Germany and various retailers in Germany. The focus on communication shows a lack in the knowledge transfer along the value chain of organic wine. Therefore, this study fills a research gap and provides valuable practical insight into the organic market for the wine industry and the scientific community.

Effect of grape yield and maceration time on phenolic composition of ‘Fetească neagră’ organic wine

The phenolic composition of wine is mostly determined by the accumulation of the phenolic compounds in the grapes, as well as their extraction into wine. To increase their concentration in grapes, yield reduction is usually performed by pruning, while to increase the extraction in wines, the maceration on skins is extended for longer periods of time. The present study focuses on the possibilities to apply both strategies to improve the polyphenol composition of organic red wines of Romanian variety ‘Fetească neagră’, which stands to benefit more from technological interventions than other varieties, which naturally accumulate higher phenol concentrations in the grapes. In the vineyard three experimental pruning variants were made, with 20, 28 and 36 buds/vine, while for wine, maceration was performed for either 8 or 16 days for each grape variant. The phenolic profiles of wines were determined by HPLC methods. The main anthocyanidins, such as malvidin, petunidin, delphinidin, peonidin and cyanidin, as well as the acylated and coumaroylated derivatives of malvidin and peonidin were quantitatively determined. Some other phenolic compounds, of various classes, such as gallic, p-benzoic, p-coumaric and ferulic acid, catechin, epicatechin, myricetin, quercetin and trans-resveratrol were also determined. The quality of the organic ‘Fetească neagră’ wines depended highly on the vintage, but yield reduction and the extension of skin maceration duration were especially beneficial in the less favourable year, when classical technologies lead to less accumulation of sugars, colour and other polyphenols. Concomitant application of both strategies led to the best results, irrespective of the year.

Premium price for natural preservatives in wine: a discrete choice experiment

The South African wine industry has recently launched the world’s first ‘no sulphite added’ wine made from indigenous Rooibos & Honeybush toasted wood chips. This wood chip contains antioxidant properties known to protect wine from oxidation. On the other hand, SO2 as a preservative, is often perceived by wine consumers as causing headaches and migraines. Differentiated wines based on their SO2 content may be a profitable marketing avenue for the struggling industry. We interviewed more than 600 wine consumers to investigate their perceptions of wine preservatives and preference for several wine attributes. Specifically, we use discrete choice experiments to elicit willingness to pay for the innovative alternative based on Rooibos & Honeybush wood chips. In addition to wine preservatives, we also examine consumers’ preferences for organic wine attributes and wine quality measured by a 100-point quality score and cost. Based on the results from the mixed logit model, we find that consumers are willing to pay an additional €3.53 (R56.48) per bottle of wine with natural Rooibos & Honeybush wood chips, while they are ready to pay €1.22 (R19.52) more for organic wine and €0.10 (R1.60) for each point on the quality score. Consumer preferences are not statistically different between red and white wine but differ considerably across consumers. In particular, those who believe SO2 in wine causes headaches are willing to pay at least three times more for replacing sulphur-based preservatives with a natural one. Marketing implications are offered for the wine industry.

Transitioning towards Organic Farming: Perspectives for the Future of the Italian Organic Wine Sector

In recent years, after the publication of Regulation (EU) 2018/848 on organic production and the labelling of organic products, all stakeholders have been considering threats and opportunities in the development of the organic food and beverage sector. The aim of the study outlined in this paper was to analyse the development prospects of the Italian organic wine sector in light of the Common Agricultural Policy (CAP) environmental and climate objectives. Specifically, the study focussed on applying a System Dynamics Approach (SDA) and a Network Analysis in order to explain how the most relevant social–economic determinants of the national organic wine sector are in all likelihood influencing the hoped-for shift from conventional to organic production. Such conversion appeared to be worth exploring because, despite the increasing global demand for organic wine, the economic effects on the entire system are still somewhat unclear from a dynamic perspective. The results of the study clearly demonstrated that public policies and regulatory actions at the national and European level will continue to be very influential for the future of the national organic wine system. Different development pathways, such as groups of operators and the adoption of the new national certification system for the sustainability of the entire wine supply chain, should be undertaken by Italian “small wine operators” in order to gain international markets.

What’s in organic wine consumer mind? A review on purchasing drivers of organic wines

Consumer interest in organic wine is growing, but the effects of organic label, consumer quality perception and the support for the benefits claim of organic wine are not yet fully understood and at times doubtful. The literature shows a very heterogeneous picture regarding consumer behaviour and preferences for organic wine. This study seeks to understand the link between organic wine and consumer’ purchasing drivers. Using a systematic literature review, the paper explores the characteristics of consumer of organic wine, the motivation on consumer behaviour and preferences for organic wine, as well as the sensory quality and the presence of additives when evaluating wine quality and in shaping consumers’ attitudes. The results show how socio-economic and psychological characteristics of consumer as well as quality perception affect their behaviour for organic wine. Little consensus on the benefits in terms of improved sensory quality of organic wine compared to conventional one. Among sensory qualities, taste has been found to be both a key driver and barrier to organic wine consumption. Based on literature studies, consumers have positive opinions toward organic wine, which is perceived as healthy and environmental friendly. However, despite the growing market interest in wine, scientific information about the organoleptic differences between conventional and organic remains scarce and the topic requires more in-depth analysis. Understanding the profile of consumer and the factors that influence consumer’ behaviour provide information to the organic wine industry.

Insights into organic wine consumption: behaviour, segmentation and attribute non-attendance

Several studies have focused on the behaviour of consumers towards organic wine, finding varying and sometimes conflicting results. Some scholars have noted that consumers may perceive wine labelled as organic to be of a lower quality, whereas others have found that consumers are willing to pay a premium price for it. Starting from these discrepancies found in the literature, this study seeks to investigate how the organic certification influences consumers when purchasing a bottle of red wine, evaluating the possible presence of attribute non-attendance (ANA) behaviour. A choice experiment was carried out on a sample of Italian wine consumers. Findings highlight that although, on average, consumers do not prefer organic wine, there is a relevant niche in the market consisting of consumers who benefit from purchasing it. Moreover, we have found that the majority of the sample ignores the organic attribute when choosing a bottle of wine, which reveals ANA behaviour.

Enabling factors for adopting sustainable, organic wine production

PurposeThis study expands the debate on the reasons that wine producers adopt sustainable, organic wine production. It aims to ascertain the enabling factors facilitating behavioral intention regarding such an adoption and whether these factors can be combined in a conceptual, measurable model.Design/methodology/approachA sample of 157 Italian winery companies was used. Results were analyzed through the unified theory of acceptance and use of technology model, various quantitative methods and a multi-regression model.FindingsGender, age, role, experience in the sector and company existence do not affect behavioral intention. Conversely, performance expectancy, effort expectancy, social influences, facilitating conditions, attitude and self-efficacy strongly affect behavioral intention, whereas the determinant anxiety has a negative effect. Further, four factors account for most of the variability in behavioral intention.Research limitations/implicationsThe research is limited to Italian wine producers, and the discussion is based on quantitative results alone. Qualitative data would probably produce a richer, more comprehensive understanding of some phenomena.Practical implicationsManagers and entrepreneurs intending to invest in organic wine production can gain a detailed understanding of factors that affect the behavioral intention toward these technologies by comparing their attitudes with those of Italian producers.Originality/valueSeveral studies have focused on wine consumers' behavior, but very few have investigated wineries' intention to adopt organic wine technology and the likely driving factors.