Ohmic heating polyphenolic extracts from vine pruning residue with enhanced biological activity

Biocontrol of Alternaria alternata in cold-stored table grapes using psychrotrophic yeasts and bioactive compounds of natural sources

Alternaria alternata is a common fungal pathogen causing postharvest decay in table grapes. This study addressed the potential of autochthonous yeasts and bioactive compounds of natural sources to act as biocontrol agents (BCAs) against A. alternata in cold-stored table grapes. With this purpose, 19 yeast capable of growing at 0-1 °C were isolated from the surface of Red Globe table grapes. These isolates, along with the pre-isolated strain Metschnikowia pulcherrima RCM2, were evaluated as BCAs in wounded berries. From these results, six yeast isolates were pre-selected to be combined with bioactive compounds of natural sources, like phenolic compounds (PCs) of side streams of wine industry, including bunch stem extract (BSE) (5-25 %), and cane extract (CE) (5-25 %), and functional polysaccharides from shrimp waste such as chitosan (CH) (0.5 %). Then, the biocontrol efficacy of combined treatments beyond individual ones was compared. The results revealed that 4 yeast isolates, namely M. pulcherrima RCM2 and ULA146, and Aureobasidium pullulans FUL14 and FUL18, were the most effective. However, when combined with the natural bioactive compounds, their efficacy against A. alternata did not increase significantly. Notably, ULA146 and FUL18 demonstrated a biocontrol efficacy of 36-37 %, comparable to that of the treatment with commercial doses of SO2, which only showed a 27 % reduction in the lesion diameter. These findings highlight the potential of using psychrotrophic yeasts as BCAs against A. alternata in cold-stored table grapes. Combining these yeast strains with BSE, CE and CH did not increase BCAs efficacy against this pathogen at the concentrations tested. The development of effective biocontrol strategies for A. alternata could contribute to reducing reliance on chemically synthesized fungicides, promoting sustainable practices, aiming to improve the quality and safety of cold-stored table grapes.

Extraction of phenolic compounds from grape pomace using ohmic heating: Chemical composition, bioactivity and bioaccessibility

This study addresses the effectiveness of ohmic heating technology (OH) for the sustainable recovery of phenolic compounds from Grape Pomace (GP) by hydroethanolic extraction. GP extracts biological potential was evaluated in terms of antioxidant activity, cytotoxicity and preventive effect against reactive oxygen species (ROS). To understand if GP extracts can be used as a functional ingredient, simulated gastrointestinal digestion was performed to evaluate the bioaccessibility. OH-assisted hydroethanolic extraction proved to be an effective process for the recovery of GP phenolic compounds with high antioxidant capacity. The digestion process increased the concentration of total phenolics and the biotransformation of high-molecular phenolics (anthocyanins, flavonoids and resveratrol) in simpler phenolic acids, improving bioaccessibility. GP extract displayed a selective action against cancer cells (Caco-2 and HeLa) and promoted ROS prevention. The results highlighted the ability of OH to extract bioactives from GP and its potential application as a nutraceutical or for functional food formulations.

Effects of ohmic heating with different voltages on the quality and microbial diversity of cow milk during thermal treatment and subsequent cold storage

Ohmic heating (OH), an innovative heating technology, presents potential applications in the pasteurization of liquid foods. Therefore, the study was conducted to evaluate the effect of OH at various voltage gradients (10 V/cm, 12.5 V/cm, and 15 V/cm) and water bath (WB) on microbial inactivation, physicochemical and sensory properties and microbial flora of pasteurized milk. Results indicated that OH with higher voltage could effectively inactivate microorganisms in milk, requiring less heating time and energy. Moreover, OH treatment at higher voltages could decelerate lipid oxidation and better maintain the sensory quality and essential amino acids content of milk. Additionally, all treatments significantly altered the microbial community, and during storage, the microbial community in milk treated with 10 V/cm and 12.5 V/cm OH remained relatively stable. OH treatments with voltage gradients exceeding 12.5 V/cm could effectively inactive microorganisms and maintain the quality attributes of milk.

Resveratrol-based biorefinery models for favoring its inclusion along the market value-added chains: A critical review

Resveratrol, a natural organic polyhydroxyphenolic compound, has gained significant attention in the last years given its potential health benefits, including antioxidant, anti-cancer, and anti-inflammatory properties. It can be directly extracted from plants, vegetables, and related products and waste resources, but also chemically/enzymatically/microbially synthesized. However, certain process strategies have some limitations, such as high costs, reduced yield or high energy demand, thus implying significant environmental loads. In this context, the search for more sustainable and circular process schemes is key to the integration of resveratrol into the market value chain of the food, cosmetic and pharmaceutical sectors. The extraction of resveratrol has traditionally been based on conventional methods such as solvent extraction, but advanced green extraction techniques offer more efficient and environmentally friendly alternatives. This review analyses both conventional and green alternative extraction technologies, as well as its bioproduction through microbial fermentation, in terms of production capacity, yield, purity and sustainability. It also presents alternative biorefinery models based on resveratrol bioproduction using by-products and waste streams as resources, specifically considering wine residues, peanut shells and wood bark as input resources, and also following a circular approach. This critical review provides some insight into the opportunities that resveratrol offers for promoting sustainable development and circularity in the related market value chains, and thus provides some criteria for decision making for biorefinery models in which resveratrol is one of the targeted high value-added products. It also identifies the future challenges to promote the inclusion of resveratrol in value chains, with the scale-up of green technologies and its demonstrated economic feasibility being the most prominent.

Comparison of ohmic heating- and microwave-assisted extraction techniques for avocado leaves valorization: Optimization and impact on the phenolic compounds and bioactivities

Avocado tree pruning activities generate a substantial amount of residual biomass, which includes different parts of the plant, such as leaves, twigs, branches, and small fruits. This study aimed to investigate the impact of different green extraction methods of microwave-assisted extraction (MAE) and ohmic heating-assisted extraction (OHAE) for the phenolic extraction of avocado leaves based on a statistical approach, central composite design (CCD), and response surface methodology (RSM). Water was preferred using as an environmentally and health-friendly solvent for both methods. The phenolic composition, antioxidant activity, and antidiabetic potential of the extracts were identified and comparatively assessed. The developed models exhibited a high degree of reliability with optimal conditions for OHAE and MAE, which were determined as 9.38 V/cm voltage gradient, 6 min extraction time, at 60°C, 5 min, and 1 g dried leaf/100 mL water. Epicatechin was identified as the primary phenolic compound in OHAE extracts, while chlorogenic acid was the dominant compound in MAE extracts. The extracts obtained from OHAE and MAE were tested for their ability to inhibit α-glucosidase activity, with IC50 (mg/mL) values of 0.85 and 1.14, respectively. The DPPH radicals scavenging activity (IC50 mg/L) of OHAE and MAE were detected as 2.96 and 3.41, respectively. In conclusion, both methods yielded extracts rich in polyphenols that displayed high antioxidant activity, but OHAE was found to be superior to MAE in terms of TPC, DPPH, and antidiabetic activities. The results of this study have the potential to make significant contributions toward promoting the principles of a circular economy by facilitating the valorization of the avocado pruning waste.

Background and Perspectives on the Utilization of Canes' and Bunch Stems' Residues from Wine Industry as Sources of Bioactive Phenolic Compounds

Viticulture activity produces a significant amount of grapevine woody byproducts, such as bunch stems and canes, which constitute potential sources of a wide range of phenolic compounds (PCs) with purported applications. Recently, the study of these byproducts has been increased as a source of health-promoting phytochemicals. Antioxidant, antimicrobial, antifungal, and antiaging properties have been reported, with most of these effects being linked to the high content of PCs with antioxidant properties. This Review summarizes the data related to the qualitative and quantitative composition of PCs recovered from canes and bunch stems side streams of the wine industry, the influence that the different environmental and storage conditions have on the final concentration of PCs, and the current reported applications in specific technological fields. The objective is to give a complete valuation of the key factors to consider, starting from the field to the final extracts, to attain the most suitable and stable characterized product.

Cocoa Bean Shell: A By-Product with High Potential for Nutritional and Biotechnological Applications

Cocoa bean shell (CBS) is one of the main solid wastes derived from the chocolate industry. This residual biomass could be an interesting source of nutrients and bioactive compounds due to its high content in dietary fibres, polyphenols and methylxanthines. Specifically, CBS can be employed as a raw material for the recovery of, for example, antioxidants, antivirals and/or antimicrobials. Additionally, it can be used as a substrate to obtain biofuels (bioethanol or biomethane), as an additive in food processing, as an adsorbent and, even, as a corrosion-inhibiting agent. Together with the research on obtaining and characterising different compounds of interest from CBS, some works have focused on the employment of novel sustainable extraction methods and others on the possible use of the whole CBS or some derived products. This review provides insight into the different alternatives of CBS valorisation, including the most recent innovations, trends and challenges for the biotechnological application of this interesting and underused by-product.

The Application of Non-Thermal Technologies for Wine Processing, Preservation, and Quality Enhancement

Recently, non-thermal wine processing technologies have been proposed as alternatives to conventional winemaking processes, mostly with the aims to improve wine quality, safety, and shelf-life. Winemakers typically rely on sulfites (SO2) to prevent wine oxidation and microbial spoilage, as these processes can negatively affect wine quality and aging potential. However, SO2 can trigger allergic reactions, asthma, and headaches in sensitive consumers, so limitations on their use are needed. In red winemaking, prolonged maceration on skins is required to extract enough phenolic compounds from the wine, which is time-consuming. Consequently, the wine industry is looking for new ways to lower SO2 levels, shorten maceration times, and extend shelf life while retaining wine quality. This review aggregates the information about the novel processing techniques proposed for winemaking, such as high-pressure processing, pulsed electric field, ultrasound, microwave, and irradiation. In general, non-thermal processing techniques have been shown to lead to improvements in wine color characteristics (phenolic and anthocyanin content), wine stability, and wine sensory properties while reducing the need for SO2 additions, shortening the maceration time, and lowering the microbial load, thereby improving the overall quality, safety, and shelf life of the wines.

Innovation and Winemaking By-Product Valorization: An Ohmic Heating Approach

The by-products of the winemaking process can represent chances for the development of new products. This study focused on the “zero waste” strategy development for by-products generated within winemaking from white and red grape varieties cultivated in the north of Portugal. The phytochemical properties of by-products were identified and characterized. Ohmic heating (OH) as a green extraction method was also applied to grape pomace due to their unknown effects on centesimal and phytochemical compositions. Both protein and carbohydrates were shown to be higher in grape bagasse than in stems. Additionally, red bagasse is richer in bioactive compounds (BC) than white bagasse. The sugar content was 21.91 and 11.01 g/100 g of DW in red and white grape bagasse, respectively. The amount of protein was 12.46 g/100 g of DW for red grape bagasse and 13.18 g/100 g of DW for white. Regarding the extraction methods, two fractions were obtained, a liquid fraction and solid (the remainder after the methodology application). OH presented a higher antioxidant capacity than a conventional (CONV) method. In addition, both extracts presented similar contents of anthocyanins, e.g., delphinidin-3-O-glucoside, petunidin-3-O-glucoside, and peonidin-3-O-glucoside. The solid fraction presented higher amounts of protein and phenols bound to fiber than CONV, which allows its use as a functional ingredient. In conclusion, OH can be an alternative extraction method compared with CONV methods, avoiding non-food grade solvents, thus contributing to circular economy implementation.

The recovery from agro-industrial wastes provides different profiles of anti-inflammatory polyphenols for tailored applications

Food and agro-industrial processing produce a great amount of side-stream and waste materials that are excellent sources of functional bioactive molecules such as phenolic compounds that recover them can be beneficial not only for food sustainability but also to human for many industrial applications such as flavor compounds and therapeutic applications such as antimicrobial and anti-inflammatory. The treatments and extraction techniques have major effects on the recovery of bioactive compounds. Along with the conventional extraction methods, numerous innovative techniques have been evolved and have been optimized to facilitate bioactive extraction more efficiently and sustainably. In this work, we have summarized the state-of-the-art technological approaches concerning novel extraction methods applied for five most produced crops in Italy; Grape Pomace (GP), Tomato Pomace (TP), Olive Pomace (OP), Citrus Pomace (CP), and Spent Coffee Grounds (SCG), presenting the extraction yield and the main class of phenolic classes, with the focus on their biological activity as an anti-inflammatory in vitro and in vivo studies via describing their molecular mechanism of action.

Assessment of Electrothermal Pretreatment of Rambutan (Nephelium lappaceum L.) Peels for Producing Cellulose Fibers

Agroindustrial wastes are renewable sources and the most promising sustainable alternative to lignocellulosic biomass for cellulose production. This study assessed the electrothermal pretreatment of rambutan peel (RP) for producing cellulose fibers. The pretreatment was carried out by Ohmic heating at a solid-to-liquid ratio of 1:10 (w/v) in a water/ethanol (1:1, v/v) mixture as the electrical transmission medium at 60 ± 1 °C for different holding times (15, 30, and 60 min). Ohmic heating did not significantly influence the total fiber yield for the various holding times. However, the compositions of the samples in terms of extractives, lignin, hemicellulose, and α-cellulose content were significantly influenced. In addition, the electrothermal pretreatment method reduced the bleaching time of RP by 25%. The pretreated fibers were thermally stable up to 240 °C. Ohmic heating pretreatment times of 15 and 30 min were found most promising, reducing the required bleaching chemicals and increasing the α-cellulose yield. The pretreated bleached cellulose fibers had similar properties to nontreated bleached fibers and could be efficiently processed into stable gels of strong shear-thinning behavior with potential application as rheology modifiers in food products. Our results demonstrate that rambutan peel could serve as a promising sustainable alternative to woody biomass for cellulose production. Ohmic heating meets the requirements for industrial applications as it is eco-friendly, improves the efficiency and energy consumption in fiber processing, and could as well be included in the processing of similar food wastes.

Impact of Circular Brewer’s Spent Grain Flour after In Vitro Gastrointestinal Digestion on Human Gut Microbiota

Brewer’s spent grain (BSG) solid residues are constituted by dietary fibre, protein, sugars, and polyphenols, which can have potential effects on human health. In this study, for the first time, the flours obtained from solid residues of solid-liquid extraction (SLE) and ohmic heating extraction (OHE) were applied throughout the gastrointestinal digestion simulation (GID), in order to evaluate their prebiotic potential and in vitro human gut microbiota fermentation. The results showed that the digestion of BSG flours obtained by the different methods lead to an increase throughout the GID of total phenolic compounds (SLE: from 2.27 to 7.20 mg gallic acid/g BSG—60% ethanol:water (v/v); OHE: 2.23 to 8.36 mg gallic acid/g BSG—80% ethanol:water (v/v)) and consequently an increase in antioxidant activity (ABTS—SLE: from 6.26 to 13.07 mg ascorbic acid/g BSG—80% ethanol:water (v/v); OHE: 4.60 to 10.60 mg ascorbic acid/g BSG—80% ethanol:water (v/v)—ORAC—SLE: 3.31 to 14.94 mg Trolox/g BSG—80% ethanol:water (v/v); OHE: from 2.13 to 17.37 mg Trolox/g BSG—60% ethanol:water (v/v)). The main phenolic compounds identified included representative molecules such as vanillic and ferulic acids, vanillin and catechin, among others being identified and quantified in all GID phases. These samples also induced the growth of probiotic bacteria and promoted the positive modulation of beneficial strains (such as Bifidobacterium spp. and Lactobacillus spp.) present in human faeces. Moreover, the fermentation by human faeces microbiota also allowed the production of short chain fatty acids (acetic, propionic, and butyric). Furthermore, previous identified polyphenols were also identified during fecal fermentation. This study demonstrates that BSG flours obtained from the solid residues of SLE and OHE extractions promoted a positive modulation of gut microbiota and related metabolism and antioxidant environment associated to the released phenolic compounds.

Increasing the added value of vine-canes as a sustainable source of phenolic compounds: A review

Grapes represent one of the most produced fruit crops around the world leading to the generation of large amounts of vine-canes as a side product, with no current economically profitable application. However, vine-canes have been demonstrated to be natural sources of phenolic compounds with numerous health benefits associated, with several potential applications. Therefore, new ambitious applications focused on their re-use are needed, targeting a sustainable process that simultaneous produces functional products and mitigates the waste generation. This review gives to the readers a complete summary about the state of the art regarding the vine-canes extracts research. Vine-canes phenolic composition is addressed and related to the health benefits exhibited. This review comprises studies from the past two decades reporting the extraction processes to recover vine-cane phenolic compounds, including conventional and environmentally friendly technologies and discussing their advantages and disadvantages. The conditions that favour the extraction process for vine-cane polyphenols for each technique were also deeply explored for the first time, enabling to the reader apply only the best parameters to achieve the highest yields without huge investment in optimizations procedures. Furthermore, a correlation between the bioactive properties of the vine-cane extracts and their applications in multiple fields is also critically presented.

Ohmic Heating Extraction at Different Times, Temperatures, Voltages, and Frequencies: A New Energy-Saving Technique for Pineapple Core Valorization

Pineapple core is considered a processing by-product. This study proposed and evaluated an ohmic heating extraction-based valorization platform to obtain value-added bioactive compounds from pineapple core and studied the effects of four important processing parameters. In this sense, a Taguchi design (L16(4)4) was used to assess the effects of temperature (70, 80, 90, and 100 °C), time (15, 30, 45, and 60 min), voltage (110, 160, 210, and 260 V), and frequency (60, 340, 620, and 900 Hz) on heating rate, come-up time, energy consumption, system performance efficiency, total phenolic compounds (TPC), DPPH, and ABTS. Finally, a side-by-side comparison of optimized ohmic heating (OOH) and conventional extraction was performed, and chemical composition was compared by ultra-performance liquid chromatography equipped with photodiode array detection-mass (UPLC-DAD-ESI-MS-MS). According to the results, increasing temperatures enhanced system performance efficiency but negatively affected TPC and antioxidant values above 90 ℃. Similarly, prolonging the extraction (>30 min) decreased TPC. Further, increasing voltage (from 110 to 260 V) shortened the come-up time (from 35.75 to 5.16 min) and increased the heating rate (from 2.71 to 18.80 °C/min−1). The optimal conditions were 30 min of extraction at 80 °C, 160 V, and 900 Hz. Verification of the optimal conditions revealed that OOH yielded an extract with valuable bioactive compounds and saved 50% of the time and 80% of energy compared to the conventional treatment. The UPLC-DAD-ESI-MS-MS showed that there were similarities between the chemical profiles of the extracts obtained by conventional and OOH methods, while the concentration of major compounds varied depending on the extraction method. This information can help achieve sustainable development goals (SDGs) by maximizing the yield and minimizing energy and time consumption.

Current Options in the Valorisation of Vine Pruning Residue for the Production of Biofuels, Biopolymers, Antioxidants, and Bio-Composites following the Concept of Biorefinery: A Review

Europe is considered the largest producer of wine worldwide, showing a high market potential. Several wastes are generated at the different stages of the wine production process, namely, vine pruning, stalks, and grape marc. Typically, these residues are not used and are commonly discarded. Portugal generates annually approximately 178 thousand metric tons of wine production waste. In this context, the interest in redirecting the use of these residues has increased due to overproduction, great availability, and low costs. The utilization of these lignocellulosic biomasses derived from the wine industry would economically benefit the producers, while mitigating impacts on the environment. These by-products can be submitted to pre-treatments (physical, chemical, and biological) for the separation of different compounds with high industrial interest, reducing the waste of agro-industrial activities and increasing industrial profitability. Particularly, vine-pruning residue, besides being a source of sugar, has high nutritional value and may serve as a source of phenolic compounds. These compounds can be obtained by bioconversion, following a concept of biorefinery. In this framework, the current routes of the valorisation of the pruning residues will be addressed and put into a circular economy context.

Vanillic Acid as a Promising Xanthine Oxidase Inhibitor: Extraction from Amomum villosum Lour and Biocompatibility Improvement via Extract Nanoemulsion

Gout is an oxidative stress-related disease. Food-derived vanillic acid, a promising xanthine oxidase inhibitor, could potentially be used as a safe, supportive, and therapeutic product for gout. The extraction of vanillic acid from a classic Chinese herbal plant Amomum villosum with ethanol was investigated in the study. The optimum conditions were determined as extraction time of 74 min, extraction temperature of 48.36 °C, and a solid-to-liquid ratio of 1:35 g·mL⁻¹ using the Box–Behnken design (BBD) of response surface methodology (RSM). The experimental extraction yield of 9.276 mg·g⁻¹ matched with the theoretical value of 9.272 ± 0.011 mg·g⁻¹ predicted by the model. The vanillic acid in Amomum villosum was determined to be 0.5450 mg·g⁻¹ by high-performance liquid chromatography–diode array detection (HPLC–DAD) under the optimum extraction conditions and exhibited xanthine oxidase (XO) inhibitory activity, with the half-maximal inhibitory concentration (IC50) of 1.762 mg·mL⁻¹. The nanoemulsion of Amomum villosum extract consists of 49.97% distilled water, 35.09% S_mix (mixture of tween 80 and 95% ethanol with 2:1 ratio), and 14.94% n-octanol, with a particle size of 110.3 ± 1.9 nm. The nanoemulsion of Amomum villosum extract exhibited markable XO inhibitory activity, with an inhibition rate of 58.71%. The result demonstrated the potential benefit of Amomum villosum as an important dietary source of xanthine oxidase inhibitors for gout.

Environmentally Friendly Techniques for the Recovery of Polyphenols from Food By-Products and Their Impact on Polyphenol Oxidase: A Critical Review

Even though food by-products have many negative financial and environmental impacts, they contain a considerable quantity of precious bioactive compounds such as polyphenols. The recovery of these compounds from food wastes could diminish their adverse effects in different aspects. For doing this, various nonthermal and conventional methods are used. Since conventional extraction methods may cause plenty of problems, due to their heat production and extreme need for energy and solvent, many novel technologies such as microwave, ultrasound, cold plasma, pulsed electric field, pressurized liquid, and ohmic heating technology have been regarded as alternatives assisting the extraction process. This paper highlights the competence of mild technologies in the recovery of polyphenols from food by-products, the effect of these technologies on polyphenol oxidase, and the application of the recovered polyphenols in the food industry.

Inhibitory activities of grape bioactive compounds against enzymes linked with human diseases

A quest for identification of novel, safe and efficient natural compounds, as additives in the modern food and cosmetic industries, has been prompted by concerns about toxicity and side effects of synthetic products. Plant phenolic compounds are one of the most documented natural products due to their multifarious biological applications. Grape (Vitis vinifera) is an important source of phenolic compounds such as phenolic acids, tannins, quinones, coumarins and, most importantly, flavonoids/flavones. This review crisply encapsulates enzyme inhibitory activities of various grape polyphenols towards different key human-ailment-associated enzymes: xanthine oxidase (gout), tyrosinase (hyperpigmentation), α-amylase and α-glucosidase (diabetes mellitus), pancreatic lipase (obesity), cholinesterase (Alzheimer's disease), angiotensin i-converting enzymes (hypertension), α-synuclein (Parkinson's disease) and histone deacetylase (various diseases). The review also depicts the enzyme inhibitory mechanism of various grape polyphenols and briefly discusses their stature as potential therapeutic and drug development candidates. KEY POINTS: • Nineteen major bioactive polyphenols from the grape/grape products and their disease targets are presented • Sixty-two important polyphenols as enzyme inhibitors from grape/grape products are presented • A thorough description and graphical presentation of biological significance of polyphenols against various diseases.

Extracts From Red Eggplant: Impact of Ohmic Heating and Different Extraction Solvents on the Chemical Profile and Bioactivity

Eggplants contain a multitude of biocompounds with nutritional and/or biological activities. The objective of this work was to study the nutritional, chemical and bioactive value of red eggplant from Rotonda, Italy. Ohmic heating (OH) was compared to conventional heating, as different solvents were used (water, ethanol 30, 50, and 90% and methanol) for biocompounds extraction. Extracts were evaluated for their total phenolic compounds, antioxidant and antibacterial activities, and its toxicity was assessed in cells, L929 and Caco-2. The nutritional characterization of Rotonda's eggplant demonstrated that it is rich in carbohydrates (65%), fiber (12.5%), proteins (13%), lipids (7.6%) and minerals. Potassium is the mineral with the highest concentration in the red eggplant (27.24 mg/g). Phenolic composition of the obtained extracts was dependent on the extraction method, as well as on the solvent. The use of OH method increased the extraction of biocompounds, especially when using 50% of ethanol as solvent. The main phenolic compounds found in the extracts of this eggplant variety were ellagic acid, p-coumaricic acid, epicatechin, narginin, taxifolin and kaempferol. Antioxidant activity was positively correlated with the total amounts of phenolics. Red Eggplant extracts showed activity against Gram-negative bacteria (E. coli and S. enterica), however, they did not demonstrate activity against Gram-positive bacteria. The extracts obtained did not show cytotoxic effects in fibroblast and colorectal studied cells. Ohmic heating is a sustainable technology that increases the extraction yield of biocompounds, with reduced energy consumption and the resulting extracts show low toxicity and high biological activity.

Recovery and virulence factors of sublethally injured Staphylococcus aureus after ohmic heating

Ohmic heating (OH) is an alternative thermal processing technique, which is widely used to pasteurize or sterilize food. However, sublethally injured Staphylococcus aureus induced by OH is a great concern to food safety. The recovery of injured S. aureus by OH and virulence factor changes during recovery were investigated in this study. The liquid media (phosphate-buffered saline, buffered peptone water and nutrient broth (NB)), temperature (4, 25 and 37 °C) and pH (6.0, 7.2 and 8.0) influenced the recovery rate and the injured cells completely repaired in NB at 37 °C, pH 7.2 with the shortest time of 2 h. The biofilm formation ability, mannitol fermentation, hemolysis, and coagulase activities decreased in injured S. aureus and recovered during repair process. Quantitative real-time PCR showed the expression of sek, clfB and lukH involved in virulence factors increased during recovery. The results indicated that the virulence factors of injured S. aureus recovered after repair.

Composition and Biological Activity of Vitis vinifera Winter Cane Extract on Candida Biofilm

Vitis vinifera canes are waste material of grapevine pruning and thus represent cheap source of high-value polyphenols. In view of the fact that resistance of many pathogenic microorganisms to antibiotics is a growing problem, the antimicrobial activity of plant polyphenols is studied as one of the possible approaches. We have investigated the total phenolic content, composition, antioxidant activity, and antifungal activity against Candida biofilm of an extract from winter canes and a commercially available extract from blue grapes. Light microscopy and confocal microscopy imaging as well as crystal violet staining were used to quantify and visualize the biofilm. We found a decrease in cell adhesion to the surface depending on the concentration of resveratrol in the cane extract. The biofilm formation was observed as metabolic activity of Candida albicans, Candida parapsilosis and Candida krusei biofilm cells and the minimum biofilm inhibitory concentrations were determined. The highest inhibition of metabolic activity was observed in Candida albicans biofilm after treatment with the cane extract (30 mg/L) and blue grape extract (50 mg/L). The composition of cane extract was analyzed and found to be comparatively different from blue grape extract. In addition, the content of total phenolic groups in cane extract was three-times higher (12.75 g_GA/L). The results showed that cane extract was more effective in preventing biofilm formation than blue grape extract and winter canes have proven to be a potential source of polyphenols for antimicrobial and antibiofilm treatment.

Continuous pressurized extraction versus electric fields-assisted extraction of cyanobacterial pigments

Cyanobacteria pigments, in special carotenoids and phycobiliproteins, are usually used in industry as raw extracts, although there is still no standard methodology for their extraction. For the co-extraction of carotenoids and phycobiliproteins from the marine cyanobacterium Cyanobium sp., a continuous pressurized solvent extraction (CPSE) system and an electric fields-assisted extraction system based in ohmic heating were optimized using Central Composite Designs, with three factors each: time (t), temperature (T) and, flow (f) for CPSE; and time, temperature and frequency (F) for ohmic heating. The content of pigments and the antioxidant capacity of extracts were evaluated. All tested factors seem to influence the extraction of pigments in different ways: a high temperature (70 °C) had a positive impact on the extraction rate in both methods, while the influence of time depended on the extraction principle. Flow and frequency affected directly the extraction efficiency and these methods are indeed suitable for cyanobacterial pigments extraction, achieving good extraction results. Optimal conditions for co-extraction of carotenoids and phycobiliproteins in CPSE were T = 70 °C, t = 20 min and f = 1.5 mL min^-1, and for ohmic heating they were T = 70 °C, t = 5 min and F = 20 kHz. Both, CPSE and ohmic heating systems allowed obtaining better extraction yields when compared with a previously optimized extraction method (homogenization), used here as a reference. However, ohmic heating was the best methodology for pigments co-extraction from Cyanobium sp.

Grape Canes from Typical Cultivars of Campania (Southern Italy) as a Source of High-Value Bioactive Compounds: Phenolic Profile, Antioxidant and Antimicrobial Activities

The purpose of the current study was to determine the phenolic composition, antioxidant, and antimicrobial activities in grape cane extracts from typical cultivars of Southern Italy. Aqueous extracts at different pHs (1-13) were prepared from "Aglianico", "Fiano", and "Greco" grape canes. The results demonstrated that an alkaline pH (13.00) produced the best polyphenol-rich extracts, as the total phenolic content was more than double when compared to the respective extracts prepared at pH 1.00. "Greco" grape canes gave the highest quantity of phenolic compounds at each pH, ranging from 42.7 ± 0.4 to 104.3 ± 3.0 mg Gallic Acid Equivalents (GAE)/g Dry Extract (DE) from pH 1.00 to 13.00. The Radical Scavenging Activity (RSA) and the Ferric Reducing Antioxidant Power (FRAP) were measured. The highest antioxidant activity was showed by "Greco" extract at pH 7.00. Seventy-five compounds were identified in the extracts by HPLC-MS with six of them described for the first time in grape canes. Procyanidins were highly abundant in extracts at pH 7.00, whereas stilbenoids were the most represented compounds at pH 13.00. Very strong antiviral activity against herpes simplex viruses was recorded for the extracts at pH 7.00 and 13.00 that were active in the early stages of infection by acting directly against the viral particles. The overall results suggest that grape canes, currently underutilized, can be usefully valorised by providing active extracts to use as antioxidant and antiviral agents.

Technological Applications of Natural Colorants in Food Systems: A Review

Natural colorants have emerged as an alternative to their synthetic counterparts due to an existing health concern of these later. Moreover, natural-food colorants are a renewable option providing health benefits and interesting technological and sensory attributes to the food systems containing them. Several sources of natural colorants have been explored aiming to deliver the required wide color range demanded by consumers. This review aimed to compare and discuss the technological applications of the main natural-food colorants into food system in the last six years, giving additional information about their extraction process. Although natural colorants are promising choices to replace synthetic ones, optimization of processing conditions, research on new sources, and new formulations to ensure stability are required to equate their properties to their synthetic counterparts.

Ohmic Heating in the Food Industry: Developments in Concepts and Applications during 2013–2020

Various technologies have been evaluated as alternatives to conventional heating for pasteurization and sterilization of foods. Ohmic heating of food products, achieved by passage of an alternating current through food, has emerged as a potential technology with comparable performance and several advantages. Ohmic heating works faster and consumes less energy compared to conventional heating. Key characteristics of ohmic heating are homogeneity of heating, shorter heating time, low energy consumption, and improved product quality and food safety. Energy consumption of ohmic heating was measured as 4.6–5.3 times lower than traditional heating. Many food processes, including pasteurization, roasting, boiling, cooking, drying, sterilization, peeling, microbiological inhibition, and recovery of polyphenol and antioxidants have employed ohmic heating. Herein, we review the theoretical basis for ohmic treatment of food and the interaction of ohmic technology with food ingredients. Recent work in the last seven years on the effect of ohmic heating on food sensory properties, bioactive compound levels, microbial inactivation, and physico-chemical changes are summarized as a convenient reference for researchers and food scientists and engineers.

Pilot-plant scale extraction of phenolic compounds from grape canes: Comprehensive characterization by LC-ESI-LTQ-Orbitrap-MS

Grape canes, also named vine shoots, are well-known viticultural byproducts containing high levels of phenolic compounds, which are associated with a broad range of health benefits. In this work, grape canes (Vitis vinifera cv. Pinot noir) were extracted in a 750 L pilot-plant reactor under the following conditions: temperature 80 °C, time 100 min, solid/liquid ratio 1:10. The comprehensive characterization of grape cane phenolic compounds was performed by liquid chromatography coupled to high-resolution/accurate mass measurement LTQ-Orbitrap mass spectrometry. A total of 44 compounds were identified and, 26 of them also quantified, consisting of phenolic acids and aldehydes (17), flavonoids (12), and stilbenoids (15). The most abundant class of phenolics were stilbenoids, among which (E)-ε-viniferin predominated. The phenolic profile of grape canes obtained using pilot plant extraction differed significantly from the results of laboratory-scale studies obtained previously. Additionally, we observed a high antioxidant capacity of grape cane pilot-plant extract measured by the radical antioxidant scavenging potential (ABTS⁺) (2209 ± 125 µmol TE/g DW) and oxygen radical absorbance capacity using fluorescein (ORAC-FL) (4612 ± 155 µmol TE/g DW). Grape cane pilot-plant extract for their phenolic profile may be used as a by-product for the development of novel nutraceutical and pharmaceutical products, improving the value and the sustainability of these residues.

Influence of the heating mechanism during the aqueous processing of vine shoots for the obtaining of hemicellulosic oligosaccharides

This work deals with the revalorization of an important winery residue such as the vine shoots by the obtaining of oligosaccharides with potential prebiotic activity. The manufacture of these added-value products was performed by an autohydrolysis treatment assisted with microwaves to make the process less time consuming and more environmentally friendly. The influence of the reaction time (0-40 min) and the temperature (140-200) on the production of oligosaccharides during the microwave-assisted autohydrolysis was evaluated. The highest concentration of oligosaccharides (168.3 g/Kg oven-dried vines shoots) was achieved during the treatment carried out at 180 °C for 20 min. To assess the benefits of the assistance of the autohydrolysis treatment with the microwaves a conventionally heated treatment was performed using conditions (180 °C for 15 min) that provoked similar effects on the solubilisation of the hemicellulosic fraction. This treatment permitted the obtaining of 203.5 g oligosaccharides/Kg oven-dried vines shoots using 61.0% more of the time needed to carry out the microwaves-assisted autohydrolysis. Although the microwave-assisted treatment permitted the manufacture of a lower amount of oligosaccharides, only consumed 28.8% of the energy needed to perform the conventionally heated treatment. The oligosaccharides manufactured by the two treatments were substituted xyloglucans with different polymerization and acetylation degrees, which due to their potential prebiotic activity could be highly appreciated by pharmaceuticals and food industries. Thus, this work demonstrated the environmental sustainability of the microwave-assisted autohydrolysis for the revalorisation of the vine shoots.

Effects of Grape Polyphenols on the Life Span and Neuroinflammatory Alterations Related to Neurodegenerative Parkinson Disease-Like Disturbances in Mice

Functional nutrition is a valuable supplementation to dietary therapy. Functional foods are enriched with biologically active substances. Plant polyphenols attract particular attention due to multiple beneficial properties attributed to their high antioxidant and other biological activities. We assessed the effect of grape polyphenols on the life span of C57BL/6 mice and on behavioral and neuroinflammatory alterations in a transgenic mouse model of Parkinson disease (PD) with overexpression of the A53T-mutant human α-synuclein. C57BL/6 mice were given a dietary supplement containing grape polyphenol concentrate (GPC—1.5 mL/kg/day) with drinking water from the age of 6–8 weeks for life. Transgenic PD mice received GPC beginning at the age of 10 weeks for four months. GPC significantly influenced the cumulative proportion of surviving and substantially augmented the average life span in mice. In the transgenic PD model, the grape polyphenol (GP) diet enhanced memory reconsolidation and diminished memory extinction in a passive avoidance test. Behavioral effects of GP treatment were accompanied by a decrease in α-synuclein accumulation in the frontal cortex and a reduction in the expression of neuroinflammatory markers (IBA1 and CD54) in the frontal cortex and hippocampus. Thus, a GP-rich diet is recommended as promising functional nutrition for aging people and patients with neurodegenerative disorders.

Ohmic Heating Extract of Vine Pruning Residue Has Anti-Colorectal Cancer Activity and Increases Sensitivity to the Chemotherapeutic Drug 5-FU

Vine pruning residues are by-products of the wine industry that have not received much attention in the past, in spite of being rich in bioactive compounds. In this study, we aimed to test whether an ohmic extract of vine pruning residue (VPE) has anti-colorectal cancer (CRC) properties, and whether responses differ according with cell's mutation profile. VPE decreased human CRC cell proliferation, accompanied by DNA effects and cell cycle modulation. VPE also increased cell sensitivity to the chemotherapeutic drug 5-FU. Our results suggest that tumors harboring BRAF mutations may be more responsive to VPE than KRAS mutated tumors. These effects of the extract were not completely reproduced by the most abundant constituents tested individually at the concentrations present in the effective dose of VPE. Globally, our results indicate that VPE, a polyphenol enriched extract produced by ohmic heating of vine pruning residue, has anti-colorectal cancer potential, including sensitizing to a chemotherapeutical drug, and its use in functional foods or nutraceuticals could be exploited in personalized anti colorectal cancer dietary strategies. Valorization of this lignocellulosic residue should encourage bio-waste recycling, adding value to this agricultural by-product and promoting the sustainable use of natural resources.

Vine-Canes as a Source of Value-Added Compounds for Cosmetic Formulations

The majority of works about vine-canes are focused on the evaluation of their chemical composition and antioxidant potential. To the best of our knowledge, the possible applications of produced extracts in cosmetic formulations have never been explored. The aim of the present study was to evaluate the antioxidant properties of vine-canes subcritical water extracts for use as active ingredients in the cosmetic industry. For that, the phenolic content and antioxidant activity of six vine-cane varieties, namely Alvarinho and Loureiro from the Minho region and Touriga Nacional and Tinta Roriz (TR) from both the Douro and Dão regions, were evaluated through spectrophotometric and chromatographic methods. All extracts presented similar antioxidant activity and the highest phenolic content was reported for TR variety from the Douro region (33.7 ± 1.9 mg GAE/g dw). The capacity of vine-cane extracts to capture reactive oxygen species superoxide (O₂^-) was also studied, with the highest IC₅₀ value being obtained for Loureiro variety (56.68 ± 2.60 µg/mL). Furthermore, no adverse effects on HaCaT and HFF-1 dermal cell lines in concentrations below 100 and 1000 µg/mL, respectively, were determined. Finally, Loureiro vine-cane extract was incorporated into a topical formulation, and physical and microbiological properties were within expected values, demonstrating that vine-canes extracts can be successfully incorporated in cosmetic products.

Green and Sustainable Valorization of Bioactive Phenolic Compounds from Pinus By-Products

In Europe, pine forests are one of the most extended forests formations, making pine residues and by-products an important source of compounds with high industrial interest as well as for bioenergy production. Moreover, the valorization of lumber industry residues is desirable from a circular economy perspective. Different extraction methods and solvents have been used, resulting in extracts with different constituents and consequently with different bioactivities. Recently, emerging and green technologies as ultrasounds, microwaves, supercritical fluids, pressurized liquids, and electric fields have appeared as promising tools for bioactive compounds extraction in alignment with the Green Chemistry principles. Pine extracts have attracted the researchers’ attention because of the positive bioproperties, such as anti-inflammatory, antimicrobial, anti-neurodegenerative, antitumoral, cardioprotective, etc., and potential industrial applications as functional foods, food additives as preservatives, nutraceuticals, pharmaceuticals, and cosmetics. Phenolic compounds are responsible for many of these bioactivities. However, there is not much information in the literature about the individual phenolic compounds of extracts from the pine species. The present review is about the reutilization of residues and by-products from the pine species, using ecofriendly technologies to obtain added-value bioactive compounds for industrial applications.

Research Advances in the Use of Bioactive Compounds from Vitis vinifera By-Products in Oral Care

Oral health is considered an important factor of general health and it contributes to the quality of life. Despite the raising awareness of preventive measures, the prevalence of oral health conditions continues to increase. In this context, a growing interest in investigating natural resources like Vitis vinifera (V. vinifera) phenolic compounds (PhCs) as oral health promoters has emerged. This paper aims to review the evidence about the bioactivities of V. vinifera by-products in oral health. Up to date, a high number of studies have thoroughly reported the antimicrobial and antiplaque activity of V. vinifera extracts against S. mutans or in multi-species biofilms. Moreover, the bioactive compounds from V. vinifera by-products have been shown to modulate the periodontal inflammatory response and the underlying oxidative stress imbalance induced by the pathogenic bacteria. Considering these beneficial effects, the utility of V. vinifera by-products in the maintaining of oral health and the necessary steps towards the development of oral care products were emphasized. In conclusion, the high potential of V. vinifera by-products could be valorized in the development of oral hygiene products with multi-target actions in the prevention and progression of several oral conditions.