Accelerated texture softening of some root vegetables by Ohmic heating

Red Beetroot Fermentation with Different Microbial Consortia to Develop Foods with Improved Aromatic Features

The European culinary culture relies on a wide range of fermented products of plant origin, produced mostly through spontaneous fermentation. Unfortunately, this kind of fermentations is difficult to standardize. Therefore, the use of commercial starter cultures is becoming common to achieve more stable, reproducible, and predictable results. Among plant-based fermentation processes, that of the red beet (Beta vulgaris L. var. conditiva) is scarcely described in the scientific literature. In this work, we compared different types of fermentation methods of beetroot and evaluated the processes' micro-biological, physico-chemical, structural, and volatilome features. A multi-variate analysis was used to match the production of specific VOCs to each starter and to define the correlations between the process variables and volatilome. Overall, the results showed a successful lactic acid fermentation. The analysis of the volatilome clearly discriminated the metabolic profiles of the different fermentations. Among them, the sample fermented with the mixture was the one with the most complex and diversified volatilome. Furthermore, samples did not appear softened after fermentation. Although this work had its weaknesses, such as the limited number of samples and variety, it may pave the way for the standardization of artisanal fermentation procedures of red beetroot in order to improve the quality and safety of the derived food products.

Innovative Preservation Methods Improving the Quality and Safety of Fish Products: Beneficial Effects and Limits

Fish products are highly perishable, requiring proper processing to maintain their quality and safety during the entire storage. Different from traditional methods used to extend the shelf-life of these products (smoking, salting, marinating, icing, chilling, freezing, drying, boiling, steaming, etc.), in recent years, some alternative methods have been proposed as innovative processing technologies able to guarantee the extension of their shelf-life while minimally affecting their organoleptic properties. The present review aims to describe the primary mechanisms of some of these innovative methods applied to preserve quality and safety of fish products; namely, non-thermal atmospheric plasma (NTAP), pulsed electric fields (PEF), pulsed light (PL), ultrasounds (US) and electrolyzed water (EW) are analysed, focusing on the main results of the studies published over the last 10 years. The limits and the benefits of each method are addressed in order to provide a global overview about these promising emerging technologies and to facilitate their greater use at industrial level. In general, all the innovative methods analysed in this review have shown a good effectiveness to control microbial growth in fish products maintaining their organoleptic, nutritional and sensory characteristics. Most of the technologies have also shown the great advantage to have a lower energy consumption and shorter production times. In contrast, not all the methods are in the same development stage; thus, we suggest further investigations to develop one (or more) hurdle-like non-thermal method able to meet both food production requirements and the modern consumers' demand.

Combinations of emerging technologies with fermentation: Interaction effects for detoxification of mycotoxins?

Consumption of foods containing mycotoxins, as crucial groups of naturally occurring toxic agents, could pose significant health risks. While the extensive scientific literature indicates that prevention of contamination by toxigenic fungi is one of the best ways to reduce mycotoxins, detoxifying strategies are useful for improving the safety of food products. Nowadays, the food and pharmaceutical industries are using the concept of combined technologies to enhance the product yield by implementing emerging techniques, such as ultrasound, ohmic heating, moderate electric field (MEF), pulsed electric field (PEF) and high-pressure processing, during the fermentation process. While the application of emerging technologies in improving the fermentation process is well explained in this literature, there is a lack of scientific texts discussing the possibility of mycotoxin degradation through the interaction effects of emerging technologies and fermentation. Therefore, this study was undertaken to provide deep insight into applying emerging processing technologies in fermentation, mechanisms and the prospects of innovative combinations of physical and biological techniques for mycotoxins' detoxification. Among various emerging technologies, ultrasound, ohmic heating, MEF, PEF, and cold plasma have shown significant positive effects on fermentation and mycotoxins detoxification, highlighting the possibility of interactions from such combinations to degrade mycotoxins in foods.

Rheological Behavior of Glycyrrhiza glabra (Licorice) Extract as a Function of Concentration and Temperature: A Critical Reappraisal

In the present study, rheological properties of twelve different licorice root extracts were evaluated using a rotational viscometer as a function of soluble solids content (15–45 °Bx) and temperature (30–70 °C). Response Surface Methodology was used to understand the relationships between the parameters. The experimental data were then fit into mathematical models. The results, for the first time, revealed that the licorice solutions had non-Newtonian shear-thinning behaviors with flow behavior indexes of 0.24 to 0.91, depending on the licorice extract samples, temperature, and °Bx. These observations were different from those reported in the literature and the present study elaborated on reasons for such observations. Further, the shear-thinning behavior generally increased by increasing the °Bx and decreasing the temperature. In addition, the power-law model was found to be suitable for predicting the experimental data. The newly revealed information can be particularly important in designing the unit operations for licorice extract processing.

Ohmic heating as a promising technique for extraction of herbal essential oils: Understanding mechanisms, recent findings, and associated challenges

The applicability of ohmic heating, as a volumetric heating technique, has been explored in various sectors of the food industry. The use of ohmic heating for essential oil extraction is among its emerging applications. This chapter overviews the recent progress in this area of research, discusses the mechanisms involved in ohmic-based essential oil extraction processes, explains the effective process parameters, highlights their benefits, and explains the considerations to address the obstacles to industrial implementation. Ohmic-assisted hydrodistillation (OAHD) and ohmic-accelerated steam distillation (OASD) systems were proposed as alternatives to conventional hydrodistillation and steam distillation, respectively. These techniques have successfully extracted essential oils from several aromatic plants (e.g., thyme, peppermint, citronella, and lavender). Both OAHD and OASD possess a number of benefits, such as reducing the extraction time and energy consumption, compared to classical extraction methods. However, these techniques are in their infancy and further economic and upscaling studies are required for their industrial adaptation.

Evaluating the Feasibility of Ohmic Cooking for Home Meal Replacement Curry: Analysis of Energy Efficacy and Textural Qualities

The feasibility of ohmic heating was tested for cooking instant home meal replacement (HMR) curry mixture. A curry mixture (curry powder, spam, carrot, potato, and water) was ohmically heated to 100 °C using different electric fields (9, 12, 15, and 18 V/cm). Temperature come-up time to 100 °C of curry soup were 5.27 ± 0.63, 3.15 ± 0.39, 2.28 ± 0.19, and 1.67 ± 0.24 min at the electric fields of 9, 12, 15, and 18 V/cm, respectively. The come-up time was decreased as a function of enhanced electric fields (P < 0.05). In terms of energy efficacy, the highest electric field (18 V/cm) resulted in the most efficient system performance coefficient (SPC), with a score of 0.62. In terms of textural qualities, cooking at 15 V/cm of carrot and potato the hardness was 3.41 ± 0.69 N and 1.04 ± 0.18 N, respectively, that resulted in the ideal level of hardness. Our study proposed the positive feasibility of ohmic heating to cook HMR curry soup.

Application of pulsed electric fields in meat and fish processing industries: An overview

The market demand for new meat and fish products with enhanced physicochemical and nutritional properties attracted the interest of the food industry and academia to investigate innovative processing approaches such as pulsed electric fields (PEF). PEF is an emerging technology based on the application of electrical currents between two electrodes thus inducing electroporation phenomena and enabling a non-invasive modification of the tissues' structure. This review provides an overview of the current knowledge on the use of PEF processing in meat and fish to enhance the physicochemical and nutritional changes, as a preservation method, as well as for improving the extraction of high added-value compounds. PEF treatment had the ability to improve several processes such as preservation, tenderization, and aging. Besides, PEF treatment could be used as a useful strategy to increase water holding properties of fish products as well as for fish drying. Finally, PEF could be also used in both meat and fish foods for by-products valorization, due to its potential to enhance the extraction of high added-value compounds. However, more studies are warranted to completely define specific treatments that can be consistently applied in the industry. This review provides the directions for this purpose in the near future.

Solubilization of bovine gelatin using power ultrasound: gelation without heating

The aim of this study was to investigate the efficacy of power ultrasound without using any heating stage in solubilizeing gelatin dispersions, and to characterize the mechanical and microstructural properties of the resulting gels using texture analysis and scanning electron microscopy, respectively. Usually to prepare a gel from gelatin, a primary heating stage of at about 40C or above is required to solubilize gelatin macromolecules. In this study solubilizing gelatin dispersions using power ultrasound without any heating was successfully performed. For solubilising gelatin, an ultrasound equipment with a frequency of 20 kHz, amplitude of 100% and power range of 50-150 W was used. Aqueous gelatin dispersions (4% w/v) were subjected to ultrasound for different times (40-240 s) at a constant temperature of 13C. Applying ultrasound to gelatin dispersions caused increases in water absorption and water solubility of the hydrocolloid. The textural parameters of the resulting gelatin gels, increased with increasing time and power of ultrasound. Moreover, a generalized Maxwell model with three elements was used for calculating relaxation times of the gels. The microstructural observations by SEM showed that the structural cohesiveness of the gels increased by increasing ultrasonication time. Ultrasound-assisted solubilization of gelatin can have emerging implications for industrial uses in pharmaceuticals, food and non-food systems.

PRACTICAL APPLICATIONS

Usually to prepare a gel from gelatin, a primary heating stage of at about 40C or above is required to solubilize gelatin macromolecules. Therefore, the use of gelatin as a hydrocolloid in food processings or pharmaceutical formulations which lack a heating step has been a technological and practical challenge. In this study solubilizing gelatin dispersions using power ultrasound without any heating was successfully performed. Ultrasound-assisted solubilisation of gelatin can have emerging implications for industrial uses in pharmaceuticals, food, and non-food systems, for example, to conserve heat sensitive compounds.