The sustainable transition of wine production systems includes non-thermal technologies, microbial biotechnologies and nature-inspired solutions. The Iberian Peninsula is a significant global wine producer, with unique geography and a strong R&D context, making it an interesting model for global trends. Spain and Portugal serve as models for using these novel technologies to reduce the environmental footprint. Emerging non-thermal technologies are of interest in the food industry, and currently, many applications have been proposed in the wine industry. These tools can process grapes or grape must to enhance the extraction of phenols, aroma compounds, and nutrients, eliminate wild microorganisms, and control deletereous enzymes. High Hydrostatic Pressure, Ultra High-Pressure Homogenization, Ultrasounds, and Pulsed Electric Fields are approved by the OIV for grape, juice, or wine treatments. Other technologies, like UV-C, are under evaluation. These methods may reduce wild microbiota and aid in starter culture implantation, supporting bio-based applications. Traditional fermentations with Saccharomyces cerevisiae have evolved to include non-Saccharomyces and malolactic bacteria in mixed cultures, reducing the use of exogenous chemicals like SO2. The approaches given in this work not only support environmental sustainability but also enhances the overall quality and safety of wine, making it a valuable contribution to the industry.

Ultra-high-pressure homogenization eliminates native microbiota in grapes. The microorganism's inactivation occurred at 300 MPa which reduce the size of all particles, including microorganisms, to the nanometric scale. Tempranillo musts were evaluated to see whether the physical-chemical and microbiological properties are optimal for conducting alcoholic fermentations using yeast starters, both Saccharomyces and non-Saccharomyces. To assess the ability of musts to be fermented, oenological parameters, aromatic volatile compounds, and chromatic properties of wines have been measured. The elimination of yeasts with UHPH treatments allowed the implantation of non-Saccharomyces yeast starters. For instance, L. thermotolerans produce 2 g/L lactic acid which avoided pigment loss when used in a consortium with T. delbrueckii strains. The possibility of having a sterile must without heat markers with required nutritional quality for yeast starters to be used is one of the features that makes UHPH interesting to be used in the winemaking industry.

Ultra-High Pressure Homogenization (UHPH) is an emerging non-thermal technology that uses continuous pumping at 200–600 MPa (generally 300), and then the fluid is depressurized against a special valve made with highly resistant alleys and coated with diamond powder. The UHPH process is able to sterilize grape juice or whatever food fluid and at the same time is extremely efficient in inactivating oxidative enzymes. The total elimination of wild microorganisms in grape juice allows the perfect implantation of the selected Saccharomyces cerevisiae starter facilitating the expression of particular metabolic profiles or the expression of specific extracellular activities. Furthermore, the use of complex emerging biotechnologies such as the use of co-inoculations with S. cerevisiae and lactic acid bacteria to perform simultaneously alcoholic and malolactic fermentations works much better if the initial juice has a very low load of wild microorganisms. Additionally, the development of spoilage processes by wild microorganisms that can remain in the wine after fermentation is practically impossible when the initial juice is treated by UHPH. Thus, UHPH helps to obtain wines more stable from a microbiological perspective and therefore safer and more hygienic.

The utilisation of non-Saccharomyces yeasts in co-inoculation and non-thermal technologies for must sterilisation is becoming increasingly prevalent due to their notable utility and potential. This new approach optimises the fermentation process and contributes to facilitating the production of wines with distinctive characteristics, improving their stability, and without organoleptic repercussions. Two trials were conducted concurrently, designated as A and B, using the same Tempranillo red must. In each trial, UHPH-treated and untreated must (serving as the control) were compared. The non-Saccharomyces yeasts (Lachancea thermotolerans and Metschnikowia pulcherrima) were identical in both trials, and fermentations were terminated by a Saccharomyces cerevisiae inoculated after 7 days (ternary fermentation). In Trial A, different percentages of the initial inoculum were employed with respect to the total volume that must be fermented, with the objective of evaluating the influence and competitiveness between yeasts. Trial B was designed to investigate the impact of two nutrients that provide vitamins, energy, and protection from oxidative stress on the development of these yeasts and their metabolic expression. Microbiological analysis and measurements of oenological parameters were carried out, acidification was assessed, volatile compounds were analysed, and the colour spectrum was measured by spectrophotometry. It was observed in both trials that the prevalence of Lachancea thermotolerans (Lt) was longer than that of Metschnikowia pulcherrima (Mp) and that the use of quercetin + thiamine had a positive effect on yeast growth. Furthermore, the combination of Lt and Mp yeasts demonstrated remarkable synergy, resulting in the production of a substantial quantity of lactic acid (>5 g/L). With regard to aroma compounds, the UHPH must have exhibited a nearly twofold increase in ethyl lactate. Additionally, the total polyphenol index (TPI) was observed to be 8-10% higher in wines derived from UHPH musts, indicating that this technology may potentially safeguard against oxidation.

Ultra High Pressure Homogenization (UHPH) consists of continuous pumping of must at pressures above 200 MPa, usually 300 MPa, and its subsequent instantaneous depressurization to atmospheric pressure after passing through a special valve. In the valve, the intense impact forces and shear stresses, together with the temperature, lead to the death of microbial cells and also to the inactivation of oxidative enzymes. Intense mechanical stresses also result in nanofragmentation of colloidal particles increasing the release of nutritional factors such as YAN and others, thus improving colloidal stability. Molecules with sensory impact such as terpenes are not affected by the UHPH process, thus preserving the varietal character, nor can thermal markers such as furfural be detected. UHPH-processed musts show and maintain higher antioxidant activity than control musts and show less browning effects during processing and even later throughout and after fermentation. This technique also affects the extraction and stability of anthocyanins and other phenolic compounds by increasing their release from cell structures and protecting them from oxidation. The antimicrobial effect and the inactivation of oxidative enzymes allow the production of wines without or with a very low level of sulfur dioxide. The ability to inactivate enzymes by affecting their tridimensional structure may also have some effect on colloidal proteins by preventing protein haze or facilitating the use of protease enzymes.

Tiger nut beverages are non-alcoholic products that are characterized by their pale color and soft flavor. Conventional heat treatments are widely used in the food industry, although heated products are often damaging to their overall quality. Ultra-high pressure homogenization UHPH) is an emerging technology that extends the shelf-life of foods while maintaining most of their fresh characteristics. The present work deals with the comparison of the effect of conventional thermal homogenization-pasteurization (H-P, 18 + 4 MPa at 65 °C, 80 °C for 15 s.) and UHPH (at 200 and 300 MPa, and inlet temperature of 40 °C), on the volatile composition of tiger nut beverage. Headspace-solid phase microextraction (HS-SPME) was used for detecting volatile compounds of beverages, which were then identified by gas chromatography-mass spectrometry (GC-MS). A total of 37 different volatile substances were identified in tiger nut beverages, which were primarily grouped into the aromatic hydrocarbons, alcohols, aldehydes and terpenes chemical families. Stabilizing treatments increased the total amount of volatile compounds (H-P > UHPH > R-P). H-P was the treatment that produced the most changes in the volatile composition of RP, while treatment at 200 MPa had a minor impact. At the end of their storage, these products were also characterized by the same chemical families. This study evidenced the UHPH technology as an alternative processing of tiger nut beverages production that minimally modifies their volatile composition.

The use of unconventional yeasts, also called non-Saccharomyces yeasts, is a hot topic in current enology due to the improvement that can be produced in the sensory profile during fermentation. However, the use of these yeasts have problems due to difficulties in the implantation and competition with wild Saccharomyces yeasts. Ultra-High Pressure Homogenization (UHPH) has demonstrated to be a powerful tool to eliminate microorganisms in grape must, specially yeast and bacteria even at low in-valve temperatures. UHPH can be considered a non-thermal technology with protective effect on sensitive molecules as terpenes and anthocyanins. The preprocessing of must by UHPH leaves it free of yeast with an optimal sensory quality, being this a perfect situation to inoculate non-Saccharomyces yeasts. We have fermented UHPH musts and controls with several non-Saccharomyces species (Lachancea thermotolerans, Metschnikowia pulcherrima, Torulaspora delbrueckii, Hanseniaspora vineae), reaching in most of the UHPH treatments better implantations of the inoculated yeasts and a complete elimination of wild yeasts. The impact of the UHPH treatment is a better expression of the metabolic and enzymatic activities of the non-Saccharomyces yeasts. That effect enhances the sensory quality and facilitates the use of non-Saccharomyces yeasts at industrial scale.

The use of high-pressure technologies is a hot topic in food science because of the potential for a gentle process in which spoilage and pathogenic microorganisms can be eliminated; these technologies also have effects on the extraction, preservation, and modification of some constituents. Whole grapes or bunches can be processed by High Hydrostatic Pressure (HHP), which causes poration of the skin cell walls and rapid diffusion of the anthocyanins into the pulp and seeds in a short treatment time (2–10 min), improving maceration. Grape juice with colloidal skin particles of less than 500 µm processed by Ultra-High Pressure Homogenization (UHPH) is nano-fragmented with high anthocyanin release. Anthocyanins can be rapidly extracted from skins using HHP and cell fragments using UHPH, releasing them and facilitating their diffusion into the liquid quickly. HHP and UHPH techniques are gentle and protective of sensitive molecules such as phenols, terpenes, and vitamins. Both techniques are non-thermal technologies with mild temperatures and residence times. Moreover, UHPH produces an intense inactivation of oxidative enzymes (PPOs), thus preserving the antioxidant activity of grape juices. Both technologies can be applied to juices or concentrates; in addition, HHP can be applied to grapes or bunches. This review provides detailed information on the main features of these novel techniques, their current status in anthocyanin extraction, and their effects on stability and process sustainability.

Currently, one of the major concerns in the wine industry is the high use of sulfur dioxide (SO2) during white winemaking as an antimicrobial and antioxidant agent. Ultra high pressure homogenization (UHPH) is an emerging nonthermal technique for continuous processing of liquid foods that could partially or totally replace the use of this enological additive. Among the main advantages provided by the application of UHPH in white vinification are the sterilization of the must, oxidation control, nutritional enrichment of the must, absence of sensory degradation, better implementation of the different fermentation biotechnologies, and deseasonalization of production. Despite causing strong reductions in particle size to reach 100–300 nm, which generates a greater initial clouding of both the must and the wine, it does not pose any additional problems when it comes to clarification and filtration. The result at the microbiological level is similar to that obtained by conventional thermal sterilization but without the disadvantages of nutritional and sensory degradation associated with the increase in temperature. It is therefore a technique with great versatility and potential for application in the enological industry.

A cryo-macerated must of V. vinifera L. cabernet sauvignon was processed by ultra-high-pressure homogenisation (UHPH) sterilisation without the use of SO 2 . The UHPH treatment of the must was carried out continuously at a pressure of 300 MPa and reaching a maximum temperature of 77 °C for less than 0.2 s. The colloidal structure of the UHPH must was evaluated by atomic force microscopy (AFM) measuring an average particle size of 457 nm. The initial microbial load was 4-log CFU/mL (yeast), 3-log CFU/mL (bacteria). No yeast and non-sporulating bacteria were detected in 1 mL and 10 mL of the UHPH-treated must, respectively. Furthermore, no fermentative activity was detected in the non-inoculated UHPH-treated musts for more than 50 days. A strong inactivation of the oxidative enzymes was observed, with lower oxidation (≈ × 3) than controls. The antioxidant activity of the UHPH-treated must was much higher (106%) than that of the control must. UHPH had a protective effect in total anthocyanins, and especially in acylated anthocyanins (+ 9.3%); furthermore, the fermentation produces fewer higher alcohol (-44,3%) and more 2-phenylethyl acetate (+ 63%).

The effect of ultra-high-pressure homogenization (UHPH) treatments at 300 MPa at inlet temperatures (Ti) between 45 and 75 °C on the microbiological, physical, and sensorial characteristics of fish broth was evaluated. Before the application of UHPH treatments, different fish broth formulations were tested, selecting the formula with the best organoleptic and nutritional characteristics and the lowest cost, containing 45% monkfish heads and rock fish in the same proportion. The microbiological shelf-life of fish broth during cold storage at 4 and 8 °C was extended by a minimum of 20 days by applying UHPH treatments at inlet temperatures (Ti) between 45 and 65 °C. Fish broth UHPH-treated at Ti = 75 °C was microbiologically sterile during storage at 4 °C, 8 °C, and room temperature. Fish broth UHPH-treated was physically stable, significantly reducing the particle size. Color showed higher luminosity and lower yellowness as the inlet temperature increased. In fish broth UHPH-treated at Ti = 75 °C, selected for its microbiological stability, no differences were observed in the nutritional composition, antioxidant activity, and sensorial perception compared to untreated fish broth. Hence, UHPH treatments showed to be an alternative to preserving fish broth with an improved microbiological shelf-life and good sensorial characteristics.

In the last decades, different non-thermal and thermal technologies have been developed for food processing. However, in many cases, it is not clear which experimental parameters must be reported to guarantee the experiments' reproducibility and provide the food industry a straightforward way to scale-up these technologies. Since reproducibility is one of the most important science features, the current work aims to improve the reproducibility of studies on emerging technologies for food processing by providing guidelines on reporting treatment conditions of thermal and non-thermal technologies. Infrared heating, microwave heating, ohmic heating and radiofrequency heating are addressed as advanced thermal technologies and isostatic high pressure, ultra-high-pressure homogenization sterilization, high-pressure homogenization, microfluidization, irradiation, plasma technologies, power ultrasound, pressure change technology, pulsed electric fields, pulsed light and supercritical CO2 are approached as non-thermal technologies. Finally, growing points and perspectives are highlighted.

This chapter reviews the main non-thermal technologies with application in enology and their impact in: the extraction of phenolic compounds from grapes, the elimination of indigenous microorganisms, and the subsequent effect in SO2 reduction. The technologies are physical processes with null or low repercussion in temperature and therefore gentle with sensory quality of grapes. High hydrostatic pressure (HHP), ultra high pressure homogenization (UHPH), pulsed electric fields (PEFs), electron-beam irradiation (eBeam), ultrasound (US), and pulsed light (PL) have interesting advantages and some drawbacks that are extensively reviewed highlighting the potential applications in current technology.

Iris LOIRA, Antonio MORATA, María Antonia BAÑUELOS, Anna PUIG-PUJOL, Buenaventura GUAMIS, Carmen GONZÁLEZ, José Antonio SUÁREZ-LEPE a enotec UPM, Département chimie et technologie des aliments, ETSIAAB, Université polytechnique de Madrid, Avenida Complutense S/N, 28040 Madrid, Espagne b Département biotechnologie et biologie végétale, ETSIAAB, Université polytechnique de Madrid, Espagne c Département de recherche œnologique, Institut de recherche et de technologie agroalimentaire, Institut catalan de la vigne et du vin (IRTA-INCAVI), Plaça Àgora, 2, 08720 Vilafranca del Penedès, Espagne d Centre d'innovation, de recherche et de transfert en technologie alimentaire (CIRTTA), TECNIO, XaRTA, Département des sciences animales et alimentaires, Faculté de médecine vétérinaire, Université autonome de Barcelone, 08193 Bellaterra, Espagne antonio.morata@upm.es

The use of UHPH sterilization in the absence of SO2 has been used to eliminate wild microorganisms and inactivate oxidative enzymes. A white must of the Muscat of Alexandria grape variety was continuously processed by UHPH at 300 MPa (inlet temperature: 23-25 degrees C). The initial microbial load of the settled must was 4-log CFU/ mL for both yeast and moulds, and slightly lower for bacteria. After UHPH processing, no microorganisms were detected in 1 mL. UHPH musts remain without fermentative activity for more than 60 days. Concentrations of the thermal markers indicated the absence of thermal damage in the UHPH-treated musts, since 5-hydroxymethylfurfural was not detected. In addition, the must treated by UHPH keeps terpene concentrations similar to those of the untreated controls. A strong inactivation of the oxidative enzymes was observed, with no browning at room temperature for more than 3 days. The antioxidant value of the UHPH-treated must was 156% higher than the control.

Ultra-high pressure homogenization (UHPH) is a high pressure technique in which a fluid is pressurized by pumping at higher than 200 MPa and instantaneously depressurized at atmospheric pressure across a special valve. The full process takes <0.2 s and the in-valve time is <0.02 s. In the valve, extremely intense impacts and shear forces produce the nanofragmentation of biological tissue at a range of 100–300 nm. The antimicrobial effect is highly effective, reaching easily inactivation levels higher than 6-log cycles even at low in-valve temperatures. At in-valve temperatures of 140–150°C (0.02 s) the destruction of thermoresistant spores is possible. Even when the temperature in-valve can be elevated (70–150°C), it can be considered a gentle technology because of the tremendously short processing time. It is easy to get outlet temperatures after valve of 20–25°C by the expansion and assisted by heat exchangers. Thermal markers as hydroxymethylfurfural (HMF) are not formed, nor are deleterious effects observed in sensitive compounds as terpenes or anthocyanins, probably because of the low effect in covalent bonds of small molecules of the high-pressure techniques compared with thermal technologies. Additionally, intense inactivation of oxidative enzymes is observed, therefore protecting the sensory and nutritional quality of fruit juices and avoiding or reducing the use of antioxidants as sulphites. UHPH can be consider a powerful and highly effective continuous and sterilizing technology without thermal repercussions, able to keep fresh juices with most of their initial sensory and nutritional quality and allowing high-quality and natural fermented derivatives as wine.

SummaryThe effect of different ultra‐high pressure homogenisation (UHPH) treatments on physicochemical and sensorial properties of orange juice was studied in comparison with thermal pasteurisation (90 °C, 1 min). UHPH treatments consisted on combinations of two inlet temperatures (10 or 20 °C) and three pressures (100, 200 and 300 MPa). Effect of treatments was assessed on general quality parameters (colour, pH, °Brix, titratable acidity, reducing sugars and non‐enzymatic browning index), particle size distribution and cloud stability. None of the UHPH treatments caused significant differences in the °Brix, reducing sugars, pH and non‐enzymatic browning index with respect of fresh or pasteurised juice. Only titratable acidity was significantly lower when inlet temperature of UHPH treatments was 20 °C. UHPH treatments significantly reduced the particle size and in consequence the cloudiness and the total colour value (∆E*) increased. The overall consumer acceptability of UHPH and pasteurised juices was similar.

Ultra-High Pressure Homogenization Sterilization (UHPHS) allows the sterilization of fluid foods at low temperatures or even in refrigeration. UHPHS is a continuous technique that allows to process 10,000 L/h with a single pump working at 300 MPa with an imbalance of 1 MPa (Ypsicon EP2409583). During the process, fluid temperature increases less than 5 ∘C. The technique is sensory gentle not affecting molecules formed by covalent bonds so aroma and pigments are unaltered. During the process of white musts, the complete elimination of yeasts, bacteria and spores can be achieved and the must may remain unfermented for several months-years if stored in amicrobic conditions. The technique is also effective in the destruction of polyphenol oxidase (PPO) enzymes. Final size particle is 100–300 nm allowing to increase the availability of yeast assimilable nitrogen and opens the opportunity to nano-encapsulate flavours. Destruction of PPOs and elimination of microorganisms help to reduce sulphites in wines. UHPHS facilitates the use of new biotechnologies such as the use of non-Saccharomyces yeasts and yeast-bacteria co-inoculations by enabling a better implantation of the starters in absence of competition with wild grape microorganisms.

Ultra-High Pressure Homogenization (UHPH) is a fast and efficient technique that can sterilize fluid foods at low temperatures or even under cooling conditions. A white must (Vitis vinifera L.) was processed at 300 MPa (inlet temperature 20 degrees C, in-valve temperature 98 degrees C, outlet temperature 25 degrees C, and time in valve 0.02 s) and their performance was compared with two untreated controls, a must that underwent a spontaneous fermentation (without SO2 addition) and another must that was sulfited with 35 mg/L of total SO2 and inoculated with the same Saccharomyces cerevisiae yeast as the UHPH-treated must. UHPH treatment led to the total elimination of grape microorganisms considering an initial population of 1 x 10(6) CFU/mL in average of wild yeasts and fungi in must, and approximately 7 x 10(3) CFU/mL of background bacteria. In a parallel assay, UHPH-processed must without yeast inoculation showed absence of fermentation for eight days at 18 degrees C. The musts treated with UHPH showed a lighter appearance (10%) before fermentation compared to the control. The triangular test verified the existence of sensory differences between the wines obtained and the preference tests showed that the judges found the wine obtained from the UHPH-treated must more fruity (3.5/5 compared with 1.5-2 in controls) and with better aroma. Industrial relevance: UHPH is an interesting way to process the must before fermentation allowing the reduction of sulfite addition while controlling wild and spoilage microorganisms.