The effects of pulsed electric fields applied to red and white wines during bottle ageing on organic acid contents

Advances in pulsed electric stimuli as a physical method for treating liquid foods

There is a need for alternative technologies that can deliver safe and nutritious foods at lower costs as compared to conventional processes. Pulsed electric field (PEF) technology has been utilised for a plethora of different applications in the life and physical sciences, such as gene/drug delivery in medicine and extraction of bioactive compounds in food science and technology. PEF technology for treating liquid foods involves engineering principles to develop the equipment, and quantitative biochemistry and microbiology techniques to validate the process. There are numerous challenges to address for its application in liquid foods such as the 5-log pathogen reduction target in food safety, maintaining the food quality, and scale up of this physical approach for industrial integration. Here, we present the engineering principles associated with pulsed electric fields, related inactivation models of microorganisms, electroporation and electropermeabilization theory, to increase the quality and safety of liquid foods; including water, milk, beer, wine, fruit juices, cider, and liquid eggs. Ultimately, we discuss the outlook of the field and emphasise research gaps.

Chemical and Sensory Characteristics of Different Red Grapes Grown in Xinjiang, China: Insights into Wines Composition

Globally, the red wine market experienced a rapid growth in the last decade, due to the superior colour, taste, and nutritional quality. The red grapes used for vinification have individual characteristics varying within the regional environment. In this study, the quality of seven grape cultivars, including Marselan, Yan 73, Muscat Hamburg, Kadarka, Merlot, Cabernet Sauvignon, and Crimpose, and their corresponding wines, were investigated based on high-performance liquid chromatography and headspace solid-phase microextraction coupled to gas chromatography–mass spectrometry. These techniques were performed to analyze the chemical compositions and volatile compounds of the tested samples, respectively. The results showed that tartaric acid (29.96% to 73.45%) and rutin (12.53% to 56.54%) were the dominant organic acid and phenolic compounds in grapes, respectively. Higher concentrations of organic acids and phenolic compounds, and the types of volatile compounds, were observed to be highest in the Cabernet Sauvignon grape. The antioxidant activity of wines ranged from 6.74 to 102.68 mmol TE/L, and Yan 73 wine had the highest antioxidant activity. A total of 69 volatile compounds consisting of 17 alcohols, 26 esters, 5 aldehydes, 9 acids, 7 ketones, and 5 other volatile compounds were identified in all tested wines, and 11 important aroma active substances (odor activity value > 1) were selected, consisting of β-ionone, phenethyl acetate, geranyl acetate, ethyl 9-decenoate, ethyl caprate, ethyl pelargonate, decanal, ethyl caprylate, 6-methyl-5-hepten-2-one, methyl 2-hexenoate, and ethyl hexanoate, which endow wines with a unique aroma. This work clearly describes the chemical and sensory characteristics of seven red grape cultivars in Xinjiang of China and provides diversity options for cultivars for winemaking.

Potential applications of pulsed electric field in the fermented wine industry

Fermented wine refers to alcoholic beverages with complex flavor substances directly produced by raw materials (fruit or rice) through microbial fermentation (yeast and bacteria). Its production steps usually include saccharification, fermentation, filtration, sterilization, aging, etc., which is a complicated and time-consuming process. Pulsed electric field (PEF) is a promising non-thermal food processing technology. Researchers have made tremendous progress in the potential application of PEF in the fermented wine industry over the past few years. The objective of this paper is to systematically review the achievements of PEF technology applied to the winemaking and aging process of fermented wine. Research on the application of PEF in fermented wine suggests that PEF treatment has the following advantages: (1) shortening the maceration time of brewing materials; (2) promoting the extraction of main functional components; (3) enhancing the color of fermented wine; (4) inactivating spoilage microorganisms; and (5) accelerating the formation of aroma substances. These are mainly related to PEF-induced electroporation of biomembranes, changes in molecular structure and the occurrence of chemical reactions. In addition, the key points of PEF treatments for fermented wine are discussed and some negative impacts and research directions are proposed.

Current Technologies to Accelerate the Aging Process of Alcoholic Beverages: A Review

The aging process contributes to the sensory evolution of alcoholic beverages, producing changes in the color and flavor of the final product. Traditionally, aging has occurred by storing beverages in wooden barrels for several months or years. To meet the demand for aged beverages, there is a need for large storage areas, a large number of wooden barrels, and, consequently, large volumes of stored product. Evaporation losses can also occur. In addition to the reactions of the beverage itself, there is also a transfer of wood compounds to the drink, which is later modified by successive oxidation reactions. This study addresses the alternative methods for accelerating the aging stage of beverages. These include the use of wood fragments, ultrasound, micro-oxygenation, pulsed electric field, high hydrostatic pressure, and microwave and gamma irradiation. These methods can be applied to optimize the process of extracting wood compounds, promote free radical formation, reduce oxidation reaction time, and accelerate yeast autolysis time. This study provides examples of some of the aforementioned methods. These technologies add value to the aging process, since they contribute to the reduction of production costs and, consequently, can increase commercial competitiveness.

Alternative Methods to SO2 for Microbiological Stabilization of Wine

The use of sulfur dioxide (SO₂ ) as wine additive is able to ensure both antioxidant protection and microbiological stability. In spite of these undeniable advantages, in the last two decades the presence of SO₂ in wine has raised concerns about potential adverse clinical effects in sensitive individuals. The winemaking industry has followed the general trend towards the reduction of SO₂ concentrations in food, by expressing at the same time the need for alternative control methods allowing reduction or even elimination of SO_2. In the light of this, research has been strongly oriented toward the study of alternatives to the use of SO₂ in wine. Most of the studies have focused on methods able to replace the antimicrobial activity of SO₂ . This review article gives a comprehensive overview of the current state-of-the-art about the chemical additives and the innovative physical techniques that have been proposed for this purpose. After a focus on the chemistry and properties of SO₂ in wine_, as well as on wine spoilage and on the conventional methods used for the microbiological stabilization of wine, recent advances on alternative methods proposed to replace the antimicrobial activity of SO₂ in winemaking are presented and discussed. Even though many of the alternatives to SO₂ showed good efficacy, nowadays no other physical technique or additive can deliver the efficacy and broad spectrum of action as SO₂ (both antioxidant and antimicrobial), therefore the alternative methods should be considered a complement to SO₂ in low-sulfite winemaking, rather than being seen as its substitutes.