Designing Next-Generation Functional Food and Beverages: Combining Nonthermal Processing Technologies and Postharvest Abiotic Stresses

Health Benefits of High Voltage Electrostatic Field Processing of Fruits and Vegetables

High voltage electrostatic field processing (HVEF) is a food preservation procedure frequently used to produce healthy minimally processed fruits and vegetables (F&V) as it reduces the growth of microorganisms and activates or inhibits various enzymes, thus retarding their natural ripening while preserving and even enhancing native nutritional quality and sensory characteristics. HVEF is one of the various nonthermal processing technology (NTPT) regarded as abiotic stress that can activate the antioxidant system of F&V and can also inhibith spoilage enzymes as, polyphenol oxidase (PPO), lipoxygenase (LOX), pectin methylesterase (PME), polygalacturonase (PG), cellulase (Cel), β-xylosidase, xyloglucan and endotransglycosylase/hydrolase, bringing positive effect on hardness, firmness, colour attributes, electric conductivity, antioxidant compounds, microstructure and decreasing electrolyte leakage (EL), malondialdehyde (MDA) contents and browning degree. This technique can also increase the contents of fructose, glucose, and sucrose and decrease the production of CO2 and H2O2. Additionally, it has been reported that HVEF could be used with other treatments, such as modified atmosphere packaging (MAP) and acidic electrolyzed water (AEW) treatment, to enhance its effects. Future works should deepen on elucidating the activation of the antioxidant systems by applying HVEF of critical enzymes related to the synthesis pathways of phenolic compounds (PC) and carotenoids (Car). Holistic approaches to the effects of HVEF on metabolism based on systems biology also need to be studied by considering the overall biochemical, physical, and process engineering related aspects of this technique.

Non-thermal technologies for the conservation of açai pulp and derived products: A comprehensive review

Açai (Euterpe oleracea) is one of the main sustainable extractive crops in the Amazon region, widely consumed by the local population and a significant export product. This review presents the current knowledge regarding nonthermal technologies employed in açai processing. This review aims to discuss and compare the main results attained by the application of HPP, ultrasound, ozone, UV light, cold plasma, and pulsed electric field on microbial inactivation, enzymatic inhibition, and the content of anthocyanin and other bioactive compounds after açai pulp processing. The discussion compares these technologies with pasteurization, the current main technology applied to açai sanitization. This review shows that there are still many gaps to be filled concerning açai processing in thermal and non-thermal technologies. Data analysis allowed the conclusion that pasteurization and HPP are, up to now, the only technologies that enable a 5-log CFU reduction of yeasts, molds, and some bacteria in açai. However, no study has reported the inactivation of Trypanosoma cruzi, which is the major gap found in current knowledge. Other technologies, such as pulsed electric field, cold plasma, and ultrasound, require further development and process intensification studies to be as successful as HPP and pasteurization.

Transforming stressed plants into healthy foods

This paper presents the current status of transforming stressed plants into healthy foods and the future trends in this emerging field. Herein, we describe the three major key elements to advance this field, including a better understanding of the mode of action of oxidative stress on nutraceutical biosynthesis under pre- and postharvest scenarios either converting plants into biofactories of nutraceuticals or creating 'functional fresh produce' while preserving quality. We discuss the need of designing healthy products based on stressed fresh produce and by-products and present a pragmatic strategy to enhance nutraceuticals in plants, and finally we propose designing appropriate studies with stressed plants targeting immunomodulatory properties to determine preventive and therapeutic effects against chronic diseases and the appropriate recommended dose.

Comprehensive review on pulsed electric field in food preservation: gaps in current studies for potential future research

In pulsed electric field (PEF) method sources of high voltage pulses are placed amid two electrodes in to fluid or paste type foods. Electricity is passed between two electrodes to sterilize the food. Almost all PEF technology entails the use of this technology in milk and milk product processing, eggs, poultry, juices and other liquid foods to prevent microorganisms. PEF technology, one of the promising methods of non-thermal preservation of food, can address the biological hazards efficiently. Recently available research papers explored PEF technology not only to facilitate the inactivation of microorganisms but also to alleviate the pressing competence for juice extraction purpose from plants for food application and also to intensify the drying and dehydration process of food. Most of the literatures are available on killing of microorganisms using PEF technology but the reports on influence of PEF technology on quality parameters of food after treatment and about their acceptability are limited. Now the technology is becoming popular and many recent papers reported about better yield and excellent quality of nutrient extracted by using PEF technology.

A comprehensive review of the benefits of drinking craft beer: Role of phenolic content in health and possible potential of the alcoholic fraction

Currently, there is greater production and consumption of craft beer due to its appreciated sensory characteristics. Unlike conventional beer, craft beers provide better health benefits due to their varied and high content of phenolic compounds (PCs) and also due to their alcohol content, but the latter is controversial. The purpose of this paper was to report on the alcoholic fraction and PCs present in craft beers and their influence on health. Despite the craft beer boom, there are few studies on the topic; there is a lot of field to explore. The countries with the most research are the United States > Italy > Brazil > United Kingdom > Spain. The type and amount of PCs in craft beers depends on the ingredients and strains used, as well as the brewing process. It was determined that it is healthier to be a moderate consumer of alcohol than to be a teetotaler or heavy drinker. Thus, studies in vitro, with animal models and clinical trials on cardiovascular and neurodegenerative diseases, cancer, diabetes and obesity, osteoporosis and even the immune system suggest the consumption of craft beer. However, more studies with more robust designs are required to obtain more generalizable and conclusive results. Finally, some challenges in the production of craft beer were detailed and some alternative solutions were mentioned.

Ultrasonic washing as an abiotic elicitor to induce the accumulation of phenolics of fresh-cut red cabbages: Effects on storage quality and microbial safety

Ultrasonic washing has been proved to be an abiotic elicitor to induce the accumulation of phenolics in some fruit and vegetables. However, the feasibility of ultrasonic washing on the accumulation of phenolics in fresh-cut red cabbages has not yet been reported. Therefore, the effects of ultrasonic washing on the phenolics and related phenolic metabolism enzymes of fresh-cut red cabbages, as well as quality and microbial safety during cold storage, were investigated. Firstly, the single-factor tests were used to optimize the ultrasonic processing parameters, including frequency mode, frequency amplitude, power density, frequency cycle time, and ultrasonic washing. Then the activities of the enzymes related to phenolic metabolisms after optimal ultrasound treatment were investigated, including phenylalanine ammonia-lyase (PAL), polyphenol oxidase (PPO), and peroxidase (POD). Additionally, the quality and microbial safety of fresh-cut red cabbages stored at 4°C under the optimal ultrasound treatment were evaluated. The results showed that the content of soluble phenolics (SPs) in fresh-cut red cabbages increased significantly during storage under the optimal conditions (28 ± 2 kHz, 60 W/L, 400 ms, and 20 min) compared with the control (P < 0.05). The PAL activity was activated and the PPO and POD activities were inhibited after ultrasonic washing, which contributed to the increase in the content of SPs. Meanwhile, the storage quality and microbial safety of fresh-cut red cabbages were improved. Ultrasonic washing reduced the weight loss and respiration rate and improved the color and texture characteristics. Additionally, the fresh-cut red cabbages after ultrasonic washing showed more retention of ascorbic acid (AA), total soluble proteins (TSPs), total soluble sugars (TSSs), and total soluble solids (SSs) compared with the control. Finally, ultrasonic washing effectively inhibited the growth of bacteria, molds and yeasts, which is beneficial to the extension of the shelf-life of fresh-cut red cabbages. Therefore, ultrasonic washing can be used as a tool to increase the content of SPs in fresh-cut red cabbages while retaining quality attributes and microbial safety.

High Hydrostatic Pressure to Increase the Biosynthesis and Extraction of Phenolic Compounds in Food: A Review

Phenolic compounds from fruits and vegetables have shown antioxidant, anticancer, anti-inflammatory, among other beneficial properties for human health. All these benefits have motivated multiple studies about preserving, extracting, and even increasing the concentration of these compounds in foods. A diverse group of vegetable products treated with High Hydrostatic Pressure (HHP) at different pressure and time have shown higher phenolic content than their untreated counterparts. The increments have been associated with an improvement in their extraction from cellular tissues and even with the activation of the biosynthetic pathway for their production. The application of HHP from 500 to 600 MPa, has been shown to cause cell wall disruption facilitating the release of phenolic compounds from cell compartments. HPP treatments ranging from 15 to 100 MPa during 10–20 min at room temperature have produced changes in phenolic biosynthesis with increments up to 155%. This review analyzes the use of HHP as a method to increase the phenolic content in vegetable systems. Phenolic content changes are associated with either an immediate stress response, with a consequent improvement in their extraction from cellular tissues, or a late stress response that activates the biosynthetic pathways of phenolics in plants.

Effects of Wounding Stress and Storage Temperature on the Accumulation of Chlorogenic Acid Isomers in Potatoes (Solanum tuberosum)

Wounding stress is an effective strategy to increase the content of bioactive compounds in horticultural crops. Potato tubers subjected to wounding stress accumulate chlorogenic acid (CGA) and CGA isomers (neo-CGA and crypto-CGA), which are phenolics that prevent and treat different chronic and degenerative diseases. In this study, the effects of wounding stress and storage temperature (10 °C and 20 °C for 168 h) on the accumulation of CGA isomers in potatoes were evaluated. Results indicated that CGA accumulation was favored when wounded potatoes were stored at 20 °C for 120 h, obtaining a 1923.1% higher concentration when compared with samples before storage. Furthermore, wounded potatoes stored at 10 °C for 120 h showed the highest neo-CGA increase in concentration (712.2%). Likewise, the highest crypto-CGA concentration (84.9% higher than control samples) was quantified in wounded potatoes stored at 20 °C for 144 h. Based on the results from both the present study and previous reports, a strategy that summarizes effective postharvest stress conditions that induce the accumulation of specific CGA isomers in potatoes is presented. The tissue with an increased content of bioactive compounds could be used as raw material to produce functional foods or could be subjected to downstream processing to produce dietary supplements.

Chocolate as Carrier to Deliver Bioactive Ingredients: Current Advances and Future Perspectives

Consumer demand for healthier foods with improved taste and convenience has urged the food industry to develop functional foods added with bioactive ingredients that can supplement basic nutrition (food supplement) or exert a pharmacological effect (nutraceuticals). Chocolate could be used as an ideal carrier to deliver bioactive ingredients, mainly due to its high acceptability by consumers. However, a drawback of using chocolate as functional food is its high sugar content, which impedes its commercialization with the diabetic population. Therefore, there is need to develop sugar-free chocolate formulations added with bioactive ingredients. Nevertheless, sugar replacement and bioactive ingredients addition is a major technological challenge that affects texture, rheology, and sensory properties of chocolate. This review is designed as a practical guide for researchers and food industries to develop the next generation of functional chocolates. Different functional chocolate formulations, including sugar-free, are reviewed as potential carriers for the delivery of bioactive compounds. The physicochemical properties and sensory acceptability of the functional chocolates presented are also highlighted. Finally, future perspectives, such as the use of nanotechnology to improve the bioaccessibility and bioavailability of active ingredients, as well as the need for clinical trials to validate the pharmacological effect of functional chocolates, are also discussed.

Physicochemical Properties and Sensory Acceptability of a Next-Generation Functional Chocolate Added with Omega-3 Polyunsaturated Fatty Acids and Probiotics

In this study, a milk chocolate formulation was developed to serve as vehicle of Omega-3 (ω3) polyunsaturated fatty acids (PUFAs) and probiotics (L. plantarum 299v and L. rhamnosus GG). Fish oil (FO) was incorporated in chocolate as a source of ω3 PUFAs. Probiotics (Prob) and FO were added during tempering, obtaining chocolates with 76.0 ± 5.2 mg (FO1) or 195.8 ± 6.5 mg (FO2) of ω3 PUFAs, and >1 × 10⁶ CFU of Prob per chocolate portion (12 g). The physicochemical properties (rheological analysis, texture, surface instrumental color, aw, and fatty acid profile), and sensory acceptability of the formulations were determined. Prob and FO generated a decrease in L* and white index (WI) values. Except for Prob + FO2, all treatments showed a decrease in aw. Rheological parameters of FO1 and Prob + FO1 presented the most similar behavior as compared with the control. Prob or FO1 addition did not affect the overall consumer’s acceptability of chocolate; and when both nutraceuticals were combined (Prob + FO1) the product showed adequate overall acceptability. FO2 formulations were not considered adequate to maintain physicochemical properties and sensory acceptability of chocolate. Results indicated that milk chocolate is a suitable vehicle for delivering ω3 PUFAs and Prob, which are essential to enhance cognitive development in children.

High Hydrostatic Pressure Processing of Whole Carrots: Effect of Static and Multi-Pulsed Mild Intensity Hydrostatic Pressure Treatments on Bioactive Compounds

In this study, the effects of static and multi-pulsed mild-intensity high hydrostatic pressure (HHP) treatments (60 or 100 MPa, ~23 °C) on the extractability and accumulation of phenolics and carotenoids in whole carrots were evaluated. HHP treatments were applied for the time needed to reach the desired pressure (come-up-time, CUT) either as a single pulse or multi-pulse (2P, 3P, and 4P). Likewise, a single sustained treatment (5 min) applied at 60 or 100 MPa was evaluated. Individual carotenoids, free and bound phenolics were quantified after HHP treatment and subsequent storage (48 h, 15 °C). As an immediate HHP response, phenolic extractability increased by 66.65% and 80.77% in carrots treated with 3P 100 MPa and 4P 60 MPa, respectively. After storage, CUT 60 MPa treatment accumulated free (163.05%) and bound (36.95%) phenolics. Regarding carotenoids, total xanthophylls increased by 27.16% after CUT 60 MPa treatment, whereas no changes were observed after storage. Results indicate that HHP processing of whole carrots at mild conditions is a feasible innovative tool to enhance the nutraceutical properties of whole carrots by increasing their free and bound phenolic content while maintaining carotenoid levels. HHP treated carrots can be used as a new functional food or as raw material for the production of food and beverages with enhanced levels of nutraceuticals.