Innovative Non-thermal Technologies Research Articles

Effects of Equivalent Processing Conditions for Microbial Inactivation by Innovative Nonthermal Technologies on the Safety, Quality, and Shelf-Life of Reineta Parda Apple Puree

This study aimed to identify equivalent processing conditions using ultrasound (US), pulsed electric fields (PEF), and high-pressure processing (HPP) for shelf-life extension and to ensure the safety and quality of Reineta Parda apple puree (AP) in comparison to conventional thermal pasteurization (72 °C/15 s, CTP). The processing conditions were selected to achieve at least 5 log CFU/g inactivation of Escherichia coli. HPP (400 MPa/1 min), US (60 °C, 20 kHz/12 min), and PEF (57.2 °C, 10 kV/cm, 70 bipolar pulses of 8 µs each) reduced E. coli counts by 6.6, 6.1, and 5.8 log CFU/g, respectively, thus achieving the pasteurization status. After processing, HPP samples showed higher levels of total antioxidant activity (DPPH and ABTS) compared to the other samples. HPP and PEF samples showed lower browning degrees than the CTP samples. All treatments ensured indigenous microbial stability (below 1 log CFU/g) for at least 30 days under refrigeration. Principal component analysis showed that the HPP samples increased their similarity to the untreated fresh AP during storage based on the pH, total soluble content and water activity, retaining its fresh-like qualities. HPP and PEF were found to be potential alternatives to the CTP of AP, resulting in a safe, minimally processed product with improved antioxidant activity.

Recent Advances in Acoustic Technology in Food Processing.

The development of food industry technologies and increasing the sustainability and effectiveness of processing comprise some of the relevant objectives of EU policy. Furthermore, advances in the development of innovative non-thermal technologies can meet consumers' demand for high-quality, safe, nutritious, and minimally processed foods. Acoustic technology is characterized as environmentally friendly and is considered an alternative method due to its sustainability and economic efficiency. This technology provides advantages such as the intensification of processes, increasing the efficiency of processes and eliminating inefficient ones, improving product quality, maintaining the product's texture, organoleptic properties, and nutritional value, and ensuring the microbiological safety of the product. This review summarizes some important applications of acoustic technology in food processing, from monitoring the safety of raw materials and products, intensifying bioprocesses, increasing the effectiveness of the extraction of valuable food components, modifying food polymers' texture and technological properties, to developing biodegradable biopolymer-based composites and materials for food packaging, along with the advantages and challenges of this technology.

Sonoprocessing of freshly squeezed orange juice: Ascorbic acid content, pectin methylesterase activity, rheological properties and cloud stability

Ultrasound performance at low energy densities (9–86 J/mL) on the quality attributes of freshly squeezed orange juice was compared to heat treatment (90 °C/1 min). Mild sonoprocessing improved orange juice's kinetic stability preserving its ascorbic acid (vitamin C) content. The ultrasound energy densities could not promote the inactivation of pectin methylesterase (PME) in the orange juice samples. However, higher energy densities contributed to their cloud stability along cold storage. In contrast, the heat processing inactivated 96.3% of PME, but thermally treated samples lost their cloudiness and had their ascorbic acid content reduced by 7%. Cloud stabilization after sonoprocessing was mainly attributed to acoustic cavitation performance to modulate particle size distribution. Ultrasound processing is a promising technique to solve one of the main technological issues of the freshly squeezed orange juice. However, mild sonoprocessing must be combined with other innovative non-thermal technologies to provide a safe and high-quality orange juice.

Effects of curcumin-mediated photodynamic treatment on lipid degradation of oysters during refrigerated storage.

Oyster's lipid degradation leads to a decrease in edible and nutritional value. Curcumin-mediated photodynamic treatment (PDT) is an innovative non-thermal technology, although evaluation of the oyster's lipid degradation has been scarce. In the present study, we investigated peroxide value, thiobarbituric acid reactive substance, triacylglycerol and free fatty acids to evaluate the effect of curcumin-mediated PDT on lipid degradation of oysters during refrigerated storage. The results showed that curcumin-mediated PDT could delay oyster's lipid degradation. Next, the activities of enzymes were detected to determine the mechanisms behind the effects of curcumin-mediated PDT. It was revealed that the activities of lipase, phospholipase A2 (PLA2 ), phospholipase C (PLC), phospholipase D (PLD) and lipoxygenase (LOX) were significantly inhibited after curcumin-mediated PDT (P < 0.05). Furthermore, 16 s rRNA analysis established that the relative abundances of Pseudoalteromonas and Psychrilyobacter were reduced by 51.58% and 43.82%, respectively, after curcumin-mediated PDT. Curcumin-mediated PDT could delay oyster's lipid degradation by inhibiting the activities of lipase, PLA2 , PLC, PLD and LOX, as well as by changing the oyster's microbial composition, reducing the relative abundance of Pseudoalteromonas and Psychrilyobacter. © 2021 Society of Chemical Industry.

Innovative Non-Thermal Technologies for Recovery and Valorization of Value-Added Products from Crustacean Processing By-Products-An Opportunity for a Circular Economy Approach.

The crustacean processing industry has experienced significant growth over recent decades resulting in the production of a great number of by-products. Crustacean by-products contain several valuable components such as proteins, lipids, and carotenoids, especially astaxanthin and chitin. When isolated, these valuable compounds are characterized by bioactivities such as anti-microbial, antioxidant, and anti-cancer ones, and that could be used as nutraceutical ingredients or additives in the food, pharmaceutical, and cosmetic industries. Different innovative non-thermal technologies have appeared as promising, safe, and efficient tools to recover these valuable compounds. This review aims at providing a summary of the main compounds that can be extracted from crustacean by-products, and of the results obtained by applying the main innovative non-thermal processes for recovering such high-value products. Moreover, from the perspective of the circular economy approach, specific case studies on some current applications of the recovered compounds in the seafood industry are presented. The extraction of valuable components from crustacean by-products, combined with the development of novel technological strategies aimed at their recovery and purification, will allow for important results related to the long-term sustainability of the seafood industry to be obtained. Furthermore, the reuse of extracted components in seafood products is an interesting strategy to increase the value of the seafood sector overall. However, to date, there are limited industrial applications for this promising approach.

Foodborne Viruses and Innovative Non-Thermal Food-Processing Technologies.

In recent years, several foodborne viruses’ outbreaks have been recorded worldwide. Μost of the foodborne viruses have a low infection dose, are stable and can persist and survive in foods for a long time without loss of infectivity. The most important foodborne viruses are: human norovirus (HuNoV), human rotavirus (HRV), hepatitis A virus (HAV), hepatitis E virus (HEV), human astrovirus (HAstV), Aichi virus (AiV), sapovirus (SaV), human adenovirus (HAdV) and enterovirus (EV). In recent years, innovative non-thermal food-processing technologies including high-pressure processing (HPP), cold plasma (CP), ultraviolet light (UV), irradiation and pulsed electric field (PEF) for improving the quality and safety of foods, including foods of animal origin, have been under research. This review presents the recent data on foodborne viruses and reviews the innovative non-thermal technologies for the control of the foodborne viruses in foods.

The potential of violet, blue, green and red light for the inactivation of P. fluorescens as planktonic cells, individual cells on a surface and biofilms

Microbial contaminations are among the major health concerns worldwide. New innovative non-thermal technologies, such as photodynamic inactivation (PDI), are emerging as mild antimicrobial treatments. This research focussed on the effects of four different colours of visible light-emitting diodes (violet, blue, green and red, at 400, 470, 522 and 644 nm) on three different types of P. fluorescens contaminations: planktonic cells, individual cells on a surface and biofilms. The results demonstrated that only violet light inactivates planktonic P. fluorescens in a suspension (0.5-log reduction). Individual cells on a surface could be inactivated (i) effectively by violet light (3.7-log reduction in 30 min) when the cells were at optimal conditions and (ii) below the detection limit by both violet and blue light when salt stress was added to the environment. Finally, for the hydrated biofilms on polystyrene surfaces, no inactivation was achieved with any of the light sources. This study suggests that PDI is a promising technology for decontamination and preservation applications in the food industry where continuous lighting can be easily applied. It is considered more suitable as a technology to prevent microbial proliferation by intensive implementation than as a method to disinfect developed microbial populations.

Thermodynamics, transport phenomena, and electrochemistry of external field-assisted nonthermal food technologies

ABSTRACTInterest in the development and adoption of nonthermal technologies is burgeoning within the food and bioprocess industry, the associated research community, and among the consumers. This is evident from not only the success of some innovative nonthermal technologies at industrial scale, but also from the increasing number of publications dealing with these topics, a growing demand for foods processed by nonthermal technologies and use of natural ingredients. A notable feature of the nonthermal technologies such as cold plasma, electrohydrodynamic processing, pulsed electric fields, and ultrasound is the involvement of external fields, either electric or sound. Therefore, it merits to study the fundamentals of these technologies and the associated phenomenon with a unified approach. In this review, we revisit the fundamental physical and chemical phenomena governing the selected technologies, highlight similarities, and contrasts, describe few successful applications, and finally, identify the gaps in research.

The application of supercritical carbon dioxide for the stabilization of native and commercial polyphenol oxidases and peroxidases in cloudy apple juice (cv. Golden Delicious)

Abstract Supercritical carbon dioxide (SCCD) was applied for the native tissue and commercial enzyme inactivation in cloudy apple juice. The polyphenol oxidases (PPO) and peroxidases (POD) inactivation kinetics significantly depended on process parameters as well as the origin of enzymes. An increase in the temperature and pressure resulted in increasing of the k-value and decrease of D-value for both types of enzymes. POD turned out to be more thermal and pressure resistant compared to PPO. The lowest decimal reduction time (D-value), zT and zP-values were noted at 65 °C and 60 MPa for native PPO: 33.8 min, 90.3 °C and 112.6 MPa, respectively. The activation energy (Ea) generally decreased with increasing the pressure, whereas activation volume (Va) increased with increasing the temperature. Overall, SCCD treatment is a promising technique to obtain high quality apple juices with low enzyme activity. Industrial relevance Apple juice is one of the most frequently consumed juices in the world. It is commonly served as a clear juice, but there is a growing market for cloudy apple juices. Unfortunately, during cloudy juice processing and storage browning is initiated by enzymatic oxidation of polyphenols. Supercritical carbon dioxide (SCCD) is an interesting method among the innovative non-thermal technologies for the inactivation of native and commercial oxidoreductases in cloudy apple juice. In this study, the data proved that SCCD processing is a promising non-thermal technique for stabilization of fresh cloudy juices.

Application of supercritical carbon dioxide for the preservation of strawberry juice: Microbial and physicochemical quality, enzymatic activity and the degradation kinetics of anthocyanins during storage

Abstract Supercritical carbon dioxide (SCCD) was applied for strawberry juice preservation. SCCD under selected parameters was effective for microflora and enzyme inactivation. For storage studies samples preserved at 30 and 60 MPa, at 45 °C for 30 min were selected. Yeasts and moulds were not detected after SCCD treatment in these conditions, whereas TMC was ~ 1.7 log CFU/g. Polyphenol oxidases were inactivated, whereas peroxidases decreased by ~ 85%. SCCD treatment resulted in the hydrolysis of sucrose and ~ 30% losses of vitamin C, which was totally decomposed after the 4th week of storage. Anthocyanins were not affected by the SCCD process and the kinetic rate constant of degradation during storage ranged from 2.12 × 10 − 2 to 3.10 × 10 − 2 (days − 1 ), and the half-time from 22.4 to 32.7 days, depending on the monomer and pressure applied. Overall, SCCD treatment seems to be a promising technique to obtain high quality strawberry juice as a safe alternative to non-pasteurized juices. Industrial relevance Strawberries are highly appreciated for their nutritional quality, colour and taste. Strawberry compounds, i.e. anthocyanins and vitamin C, are heat sensitive. These nutrients as well as colour are degraded when the fruits are processed using high temperature treatment. Supercritical carbon dioxide (SCCD) is an interesting method among the innovative non-thermal technologies for the preservation of fruit products. In this study, the data proved that SCCD processing is a promising non-thermal alternative to pasteurization to preserve fresh cloudy strawberry juice.

High-Power Ultrasound Assisted High-Pressure Carbon Dioxide Pasteurization of Fresh-Cut Coconut: a Microbial and Physicochemical Study

A combined treatment based on high-pressure carbon dioxide and high-power ultrasound (HPCD + HPU) technologies was investigated for the pasteurization of fresh-cut coconut. Inactivation kinetics of both the natural microbiota and Salmonella enterica typhimurium spiked on the product were determined at 12 MPa and 10 W, delivered every 2 min of treatment, as a function of temperature (from 24 to 50 °C) and treatment time (from 5 up to 30 min). Additionally, to study the effect of HPCD + HPU on the quality of the product, physicochemical attributes (total acidity, pH, color, texture, dry matter, fat content, enzymatic activity, antioxidant capacity, phenols, flavonoids, and phenolic acids) were measured after the combined treatment and during a refrigerated shelf life of 4 weeks. The results revealed that HPCD + HPU increased microbial inactivation rates compared with HPCD alone: 8 log reductions of S. typhimurium were achieved with HPCD + HPU at 12 MPa, 40 °C, 20 min, while just a 4 log reduction was achieved with HPCD alone. Similar results were obtained for the natural microbiota; milder conditions of temperature and pressure were sufficient to assure inactivation to undetectable levels even of mesophilic microorganisms, the most resistant ones. Total acidity and pH did not change after the combined treatment and during the entire storage of 4 weeks, while slight differences were observed for the other physicochemical parameters. Overall, the results showed the feasibility and the potential of HPCD + HPU as an innovative non-thermal technology for the pasteurization of fresh-cut fruits.

Effect of pulsed light on structural and physiological properties of Listeria innocua and Escherichia coli

The application of broad-spectrum intense light pulses is an innovative nonthermal technology for the decontamination of packaging materials, liquids or foodstuffs. The objective of this study was the fundamental investigation of the cellular impact of a pulsed light treatment on Listeria innocua and Escherichia coli. Flow cytometry in combination with different fluorescent stains, conventional plate count technique and a viability assay were applied to investigate the effects of a pulsed light treatment on the physiological properties of L.innocua and E.coli. The results showed that loss of cultivability occurred at considerably lower fluences than the shutdown of cellular functions such as the depolarization of cell membranes, the loss of metabolic, esterase and pump activities or the occurrence of membrane damage. Therefore, a considerable proportion of cells appeared to have entered the viable but nonculturable (VBNC) state after the pulsed light treatment. A high percentage of L.innocua was able to maintain certain cellular vitality functions after storage overnight, whereas a further decrease in vitality was observed in case of E.coli. The loss of culturability was on the other hand directly accompanied by the formation of reactive oxygen species (ROS) and DNA damages, which were assessed by the ROS-sensitive probe DCFH-DA and RAPD-PCR, respectively. A significant discrepancy between conventional plate counts and different viability staining parameters was observed, which shows that a pulsed light treatment does not cause an immediate shutdown of vitality functions even when the number of colony-forming units already decreased for more than 6 log10 sample(-1) . Oxidative stress with concomitant damage to the DNA molecule showed to be directly responsible for the loss of cultivability due to pulsed light rather than a direct rupture of cell membranes or inactivation of intracellular enzymes. The presented results suggest an UV light-induced photochemical rather than a photothermal or photophysical inactivation of bacterial cells by pulsed light under the applied experimental conditions. Flow cytometry in combination with different viability stains proved to be a suitable technique to gain deeper insight into the cellular response of bacteria to inactivation processes like a pulsed light treatment.