Investigation of technological approaches for reduction of methanol formation in plum wines

Comprehensive Analysis of Physicochemical Properties and Volatile Compounds in Different Strawberry Wines under Various Pre-Treatments

Pre-fermentation treatment has an important impact on the color, aroma, taste, and other characteristics of fruit wine. To discover suitable pre-treatment techniques and conditions that yield strawberry wine of excellent quality, the influences of juice fermentation, pulp maceration, thermovinification, and enzymatic hydrolysis pre-treatments on the basic chemical composition, color, antioxidant capacity, and volatile organic compounds in strawberry wines were investigated. The results showed that the color, antioxidant properties, and volatile aroma of strawberry wines fermented with juice were different from those with pulp. Strawberry wines fermented from juice after 50 °C maceration had more desirable qualities, such as less methanol content (72.43 ± 2.14 mg/L) compared with pulp-fermented wines (88.16 ± 7.52 mg/L) and enzymatic maceration wines (136.72 ± 11.5 mg/L); higher total phenolic content (21.78%) and total flavonoid content (13.02%); enhanced DPPH (17.36%) and ABTS (27.55%) free radical scavenging activities; richer essential terpenoids and fatty acid ethyl esters, such as linalool (11.28%), ethyl hexanoate (14.41%), ethyl octanoate (17.12%), ethyl decanoate (32.49%), and ethyl 9-decenoate (60.64%); pleasant floral and fruity notes compared with juice-fermented wines macerated at normal temperatures; and a lighter color. Overall, juice thermovinification at 50 °C is a potential pre-treatment technique to enhance the nutrition and aroma of strawberry wine.

Mezcal Production in Mexico: Between Tradition and Commercial Exploitation

Mezcal is a traditional iconic Mexican distilled beverage obtained from varied species of agaves. Regardless of the area of production, the process always consists of five stages: harvesting the agaves, cooking, crushing, fermentation, and distillation. It is produced in a large area of Mexican territory, a large part of which is protected by the Denomination of Origin mezcal (DOM). Over time, the word mezcal has evolved from a generic name to a more specific term used to describe the agave-distilled beverages produced in the territory protected by the DOM under the Mexican official standard NOM-070-SCFI-2016 which defined Mezcal as a “Mexican distilled alcoholic beverage, 100% from maguey or agave, obtained by distillation of fermented juices with spontaneous or cultivated microorganisms, extracted from mature heads of maguey or cooked agaves, harvested in the territory covered by the DOM.” In the last 10 years, official production has increased, from <1 million liters in 2011 to almost 8 million liters. This substantial increase in production puts a lot of pressure on resources, in particular raw material, as part of the production is obtained from wild agave. On the other hand, it exposes tradition at risk by increasing production by modernizing production processes and sacrificing the artisanal aspect of this production. We consider appropriate to address the issue of sustainability in this context of great tradition and growing market demand. The article presents the relevant aspects of mezcal production, highlighting some particularities specific to certain production areas, it also addresses the problem of the official standard. A broad discussion is presented on the sustainability of artisanal processes, and the main points to be taken care of in this framework. Additionally, some elements considered as fundamental in the perspective of the design of a sustainable artisanal distillery are described. In summary, this article aims to review the current state of mezcal production, how sustainability may be addressed in a very artisanal process and what are the challenges of the production chain to satisfy an increase in demand without sacrificing the tradition and culture related to this iconic Mexican beverage.

Effect of bentonite and calcium chloride on apple wine

BACKGROUND

Apple wine is a popular alcoholic beverage for its nutrition and fresh taste. However, the methanol existing in apple wine restricts its quality. Unfortunately, there are no methods to reduce the methanol content in fruit wine. To this end, bentonite (B), calcium chloride (CC) and their combination (B&CC) were added into apple juice in this study. The treated juice (0) and supernatant obtained by standing the juice at 25 °C for 24 h were fermented at 25 °C and 10 °C, respectively.

RESULTS

Bentonite was an excellent methanol interrupter, a pectin retainer and a wine quality defender both at 25 and 10 °C. The lowest methanol content of 1.41 mg L^-1 and higher pectin content of 84.74 mg L^-1 were reached in the finished wine by B0 at 10 °C. Calcium chloride decreased pectin content, elevated methanol content and changed the profile of individual organic acids. In fact, the wine by B&CC0 at 25 °C showed dramatic changes in individual organic acids. The content of l-malic acid and succinic acid was only 2.22% and 6.29% of the control, respectively, while the lactic acid content was 17.72 times that of the control.

CONCLUSIONS

It is suggested that B0 and fermented at 10 °C was the most effective way to decrease methanol content, retain pectin content and defend wine quality. © 2021 Society of Chemical Industry.

Application of natural and synthetic zeolites in the oenological field

Zeolites are crystalline hydrated aluminosilicates, of natural or synthetic origin, characterized by a microporous structure and high adsorption properties. They are employed as soil amendments and fertilizer carriers in agriculture, as catalysts, detergents, adsorbents and molecular sieves in many chemical processes, as well as in water and soil decontamination, and in food processing. They have been also tested in the oenological field for several potential applications; yet an overview on such topic is not still available. The present review summarizes the recent and innovative applications of zeolites in winemaking and supplies a critical discussion about their potential to prevent protein haze, tartrate instability or the appearance of certain defects, like light-struck off-flavour and earthy off-flavours. Further applications of these minerals in the management of winery wastes and in the analytical field are also reviewed. The outcomes of this work evidenced the need of further research on the use of zeolites in oenology for better exploiting their peculiar sorption and exchange properties, selecting the most efficient natural types and improving the performances of the synthetic ones, without disregarding the potential secondary effects of these treatments on wine quality.

Methanol Mitigation during Manufacturing of Fruit Spirits with Special Consideration of Novel Coffee Cherry Spirits

Methanol is a natural ingredient with major occurrence in fruit spirits, such as apple, pear, plum or cherry spirits, but also in spirits made from coffee pulp. The compound is formed during fermentation and the following mash storage by enzymatic hydrolysis of naturally present pectins. Methanol is toxic above certain threshold levels and legal limits have been set in most jurisdictions. Therefore, the methanol content needs to be mitigated and its level must be controlled. This article will review the several factors that influence the methanol content including the pH value of the mash, the addition of various yeast and enzyme preparations, fermentation temperature, mash storage, and most importantly the raw material quality and hygiene. From all these mitigation possibilities, lowering the pH value and the use of cultured yeasts when mashing fruit substances is already common as best practice today. Also a controlled yeast fermentation at acidic pH facilitates not only reduced methanol formation, but ultimately also leads to quality benefits of the distillate. Special care has to be observed in the case of spirits made from coffee by-products which are prone to spoilage with very high methanol contents reported in past studies.

Recent advances in the biological valorization of citrus peel waste into fuels and chemicals

In the quest to reduce global food loss and waste, fruit processing wastes, particularly citrus peel waste (CPW), have emerged as a promising and sustainable option for biorefinery without competing with human foods and animal feeds. CPW is largely produced and, as recent studies suggest, has the industrial potential of biological valorization into fuels and chemicals. In this review, the promising aspects of CPW as an alternative biomass were highlighted, focusing on its low lignin content. In addition, specific technical difficulties in fermenting CPW are described, highlighting that citrus peel is high in pectin that consist of non-fermentable sugars, mainly galacturonic acid. Last, recent advances in the metabolic engineering of yeast and other microbial strains that ferment CPW-derived sugars to produce value-added products, such as ethanol and mucic acid, are summarized. For industrially viable CPW-based biorefinery, more studies are needed to improve fermentation efficiency and to diversify product profiles.

Effect of different pre-treatment maceration techniques on the content of phenolic compounds and color of Dornfelder wines elaborated in cold climate

This study present the effects of different pre-treatment maceration techniques (microwave, thermo-maceration, and enzymatic treatment) on the content of phenolic compounds (by UPLC-PDA) and their redox potential by cyclic voltammetry (CV), antioxidant capacity (ABTS radical cation decolorization assay and FRAP as Ferric Reducing Ability of Plasma), and other basic chemical properties of red wine made from cv. Dornfelder. The pre-treatment maceration technique significantly (p < 0.05) affected the content of total phenolics in Dornfelder must (freshly crushed grapes), with particularly high amounts in the must pre-treated by microwaves (4344.0 mg/100 mL), and the lowest in the must pre-treatment by thermo-maceration (2979.8 mg/100 mL). A positive correlation was found between the content of total phenolics and antioxidant activity (R = 0.69 and 0.52 by ABTS and FRAP assay, respectively) and individual groups of polyphenols (for ABTS assay with anthocyanins, flavonols, flavan-3-ols, respectively R = 0.60, 0.64 and 0.66, while for FRAP method only for anthocyanins R = 0.79). The highest antioxidant activity was also determined for the variant with microwave pre-treatment (must 3.31 mM and 3.05 mM Trolox/100 mL for ABTS and FRAP assay, respectively). Following the fermentation and maturation, the amount of polyphenols decreased. No thermal pre-treatment maceration methods gave lighter or redder must. After winemaking process all the samples were characterized by less red and more yellow shade.

Physicochemical and Sensory Properties of Wine Produced from Blended Cactus Pear (Opuntia ficus-indica) andLantana camara(L. camara) Fruits

Blending different fruits as well as adding medicinal herbs improves important physicochemical and sensorial properties of fruit wine. The present study aimed at investigating prominent physicochemical and sensory properties of wine produced from cactus pear andLantana camarafruit juice blend. Both fruit juices were characterized based on pH, sugar, titratable acidity, total phenol, and organic acid contents. The fermentation process was made at previously optimized fermentation temperature of 24.8°C, pH of 3.4, inoculum concentration (Saccharomyces cerevisiae) of 10.16% (v/v), andLantana camarafruit juice concentration of 10.66% (v/v). The final wine was characterized as having pH of 3.47 ± 0.04, 4.6 ± 0.02 g/L sugar equivalent to dextrose, 0.33 ± 0.006% titratable acidity (w/v citric acid), total phenol of 696.1 ± 22.1 mg/L equivalent to gallic acid, and 4.35 ± 0.4 mg/mL organic acid equivalent to citric acid composition. Predominant color intensity, ethanol, methanol, total sulfite, and sensory value of the final wine were measured as 48.07 ± 2.66% of yellowish color, 8.6 ± 0.68% (v/v), 124.4 ± 9.5 mg/L, 129.94 ± 4.04 mg/L, and 8.65 ± 0.92, respectively. The blendedLantana camarafruit enhanced total phenol, color, and sensory value of the final wine. Titratable acidity and methanol and sulfite contents of the final wine are in an acceptable limit compared to standards for commercial wines. Utilizing cactus pear fruit by incorporatingLantana camarafruit for health-enhancing functional food development such as fruit wines could solve the current postharvest loss of both fruits and be a means of alternative beverage.