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Editorial

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3 pages, 188 KiB

Open AccessEditorial

Non-Thermal Technologies for Food Processing

by Filipa Vinagre Marques Silva and Indrawati Oey

Appl. Sci. 2023, 13(13), 7734; https://0-doi-org.brum.beds.ac.uk/10.3390/app13137734 - 30 Jun 2023

Cited by 1 | Viewed by 999

Abstract

This Special Issue covers the utilization of non-thermal technologies, specifically high pressure processing (HPP) or high hydrostatic pressure (HHP), pulsed electric field (PEF), ultrasound (US), and ultraviolet (UV) for food processing and preservation [...] Full article

(This article belongs to the Special Issue Non-thermal Technologies for Food Processing)

Research

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11 pages, 831 KiB

Open AccessArticle

Comparison of Thermal and High-Pressure Pasteurization on Immunoglobulins, Lysozyme and Microbial Quality of Donkey Colostrum

by Mafalda S. Gonçalves, Liliana G. Fidalgo, Silvia G. Sousa, Rui P. Queirós, Sónia M. Castro, Carlos A. Pinto and Jorge A. Saraiva

Appl. Sci. 2024, 14(4), 1592; https://0-doi-org.brum.beds.ac.uk/10.3390/app14041592 - 17 Feb 2024

Viewed by 446

Abstract

The effect of thermal pasteurization (TP, 62.5 °C/30 min—conditions similar to those used in milk banks/hospitals, known as Holder pasteurization) and high-pressure pasteurization (HPP: 400–625 MPa/2.5–30 min) was studied on immunoglobulin (IgG, IgM and IgA) content, lysozyme activity and microbial load of donkey [...] Read more.

The effect of thermal pasteurization (TP, 62.5 °C/30 min—conditions similar to those used in milk banks/hospitals, known as Holder pasteurization) and high-pressure pasteurization (HPP: 400–625 MPa/2.5–30 min) was studied on immunoglobulin (IgG, IgM and IgA) content, lysozyme activity and microbial load of donkey colostrum (in this case, after 40 days at 4 °C). IgG level remained unchanged with HPP at 400 MPa, increased up to 4-fold at 625 MPa/10 min and decreased 90% with TP, while IgM decreased progressively with pressure treatment intensity increment to below the detection limit at 625 MPa and decreased 20% with TP. IgA decreased to below the detection limit after TP and all HPP treatments. Lysozyme activity presented overall a higher decrease after TP (37%) compared to HPP (decreasing from 20% at 400 MPa to about 40% at 600 MPa/10 and 30 min). Furthermore, both total aerobic mesophiles and Enterobacteriaceae remained below detection limits after 40 days of refrigerated storage for both TP and HPP. So, HPP can be considered a potential alternative to the conventional TP to preserve donkey colostrum, with overall equal to better retention, particularly for IgG and lysozyme activity. As far as the authors are aware, this is the first study evaluating the effects of HPP on donkey colostrum, and research in this field should be pursued. Full article

(This article belongs to the Special Issue Non-thermal Technologies for Food Processing)

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15 pages, 1701 KiB

Open AccessArticle

High-Pressure Effects on Selected Properties of Pea and Soy Protein Isolates

by Rui Queirós, Rita Ferreira, Jorge A. Saraiva and José A. Lopes-da-Silva

Appl. Sci. 2023, 13(4), 2359; https://0-doi-org.brum.beds.ac.uk/10.3390/app13042359 - 12 Feb 2023

Cited by 3 | Viewed by 1097

Abstract

The use of vegetable proteins has been the focus of research efforts to develop new products and/or to replace other sources of protein. Ergo, there is a need to assess the effects of new processing technologies on this type of protein. This work [...] Read more.

The use of vegetable proteins has been the focus of research efforts to develop new products and/or to replace other sources of protein. Ergo, there is a need to assess the effects of new processing technologies on this type of protein. This work evaluated the influence of high-pressure processing (HPP) (pressure: 200, 400 and 600 MPa; holding time: 5, 10 and 15 min) on selected properties of pea (PPI) and soy (SPI) protein isolates at three pH values (6, 7 and 8). SPI presented a higher percentage of soluble proteins than PPI, still, HPP increased protein solubility of both isolates. This effect was more pronounced on SPI, particularly at pH 7 and 8, where the percentage of soluble proteins almost tripled under some HPP conditions. Similarly, the surface hydrophobicity also increased with HPP for proteins from both sources, increasing, in general, with increasing pressure and holding time. On the contrary, the content of free sulfhydryl groups generally decreased with HPP for proteins from both sources, suggesting a complex balance between protein unfolding and further aggregation under certain conditions. The effects of HPP on the emulsifying properties of the protein isolates were dependent on pH, pressure, holding time and whether the soluble or total fraction of the protein isolates were used. Full article

(This article belongs to the Special Issue Non-thermal Technologies for Food Processing)

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22 pages, 2821 KiB

Open AccessArticle

Understanding the Mechanism of How Pulsed Electric Fields Treatment Affects the Digestibility and Characteristics of Starch in Oat Flour

by Sheba Mae M. Duque, Sze Ying Leong, Dominic Agyei, Jaspreet Singh, Nigel Larsen, Kevin Sutton and Indrawati Oey

Appl. Sci. 2022, 12(20), 10293; https://0-doi-org.brum.beds.ac.uk/10.3390/app122010293 - 13 Oct 2022

Cited by 5 | Viewed by 1515

Abstract

The objective of this study was to evaluate the effect of pulsed electric fields (PEF) on the in vitro starch digestibility properties of oat flour. A wide range of PEF process intensity was investigated (electric field strength between 2.1 and 4.5 kV/cm and [...] Read more.

The objective of this study was to evaluate the effect of pulsed electric fields (PEF) on the in vitro starch digestibility properties of oat flour. A wide range of PEF process intensity was investigated (electric field strength between 2.1 and 4.5 kV/cm and specific energy inputs between 52 and 438 kJ/kg using 20 μs square wave bipolar pulse at 100 Hz). The results revealed that PEF applied at a high electric field strength and energy <216 kJ/kg was favourable in slowing down the rate of starch digestibility (by 48%) during in vitro gastrointestinal digestion. This is accompanied by a significant decrease (from 15% to 7–10%) in the proportion of rapidly digestible starch (RDS) and a significant increase (from 77% to 84–85%) in resistant starch (RS) fraction. The application of PEF at energy level >421 kJ/kg at any field strength intensities raised the RDS (from 15% to 19–20%), but the rate of starch digestion was not affected (maintained at 3.3–3.7 × 10⁻² min⁻¹ vs. untreated at 3.8 × 10⁻² min⁻¹). Further analysis of the structure, particle size, and thermal stability of PEF-treated oat flour through fractionation into three distinct flour segments revealed that PEF could cause major modifications in the particle size, damage and aggregation of starch granules, and destruction of the long- and short-range ordered structures of starch. Data gathered in this study indicate that PEF treatment can be a reliable strategy to modulate the in vitro starch digestibility of oat flour, either by reasonably slowing down the digestion rate or enabling a slightly higher amount of starch to be readily accessible by digestive enzymes without affecting the digestion rate. Full article

(This article belongs to the Special Issue Non-thermal Technologies for Food Processing)

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16 pages, 2948 KiB

Open AccessArticle

Effect of High Hydrostatic Pressure Processing on Starch Properties of Cassava Flour

by Ladie Anne Conde, Biniam Kebede, Sze Ying Leong and Indrawati Oey

Appl. Sci. 2022, 12(19), 10043; https://0-doi-org.brum.beds.ac.uk/10.3390/app121910043 - 06 Oct 2022

Cited by 3 | Viewed by 1863

Abstract

The aim of this study was to utilize high-pressure processing (HPP) to modify cassava flour through altering the starch components. Specifically, the effect of HPP processing variables, i.e., pressure (0.10 or untreated, 300, 400, 500, and 600 MPa), flour concentration (FC; 10, 20, [...] Read more.

The aim of this study was to utilize high-pressure processing (HPP) to modify cassava flour through altering the starch components. Specifically, the effect of HPP processing variables, i.e., pressure (0.10 or untreated, 300, 400, 500, and 600 MPa), flour concentration (FC; 10, 20, and 30%), and holding time (HT; 10 and 30 min) on starch-related properties was studied. Microstructural integrity, thermal properties, and starch susceptibility to digestive enzymes were determined. A three-way ANOVA was performed to identify the interaction effect between these process variables. In general, 600 MPa consistently transformed the crystalline starch into an amorphous one. HPP-induced gelatinization led to enlarged starches with loss of birefringence, reduced relative crystallinity percentage, and changes in short-range order. The three-way interaction between the process variables was evident in the significant progressive rise in onset gelatinization temperature and degree of gelatinization, and the decline in gelatinization enthalpy from 500 to 600 MPa with decreasing FC and increasing HT. These changes caused an increased percentage of rapidly digestible starch and decreased resistant starch fraction. Overall, this study’s results imply the possibility of using HPP to modify the starch component in cassava flour and potentially create flours with varying levels of functionalities. Full article

(This article belongs to the Special Issue Non-thermal Technologies for Food Processing)

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19 pages, 1802 KiB

Open AccessArticle

Physical, Chemical and Microbiological Properties during Storage of Red Prickly Pear Juice Processed by a Continuous Flow UV-C System

by Gabriela Mesta-Vicuña, Armando Quintero-Ramos, Carmen Oralia Meléndez-Pizarro, Tomás Galicia-García, Miguel Ángel Sánchez-Madrigal, Efrén Delgado and Martha Graciela Ruiz-Gutiérrez

Appl. Sci. 2022, 12(7), 3488; https://0-doi-org.brum.beds.ac.uk/10.3390/app12073488 - 30 Mar 2022

Cited by 1 | Viewed by 1724

Abstract

The effects of pH (3.6 and 7.0) and irradiation UV-C dose irradiation (0, 9.81, 15.13, and 31.87 mJ/cm²) on the physicochemical properties and natural microbiota of red prickly pear juice were evaluated during processing and storage. Thermal treatments were used as [...] Read more.

The effects of pH (3.6 and 7.0) and irradiation UV-C dose irradiation (0, 9.81, 15.13, and 31.87 mJ/cm²) on the physicochemical properties and natural microbiota of red prickly pear juice were evaluated during processing and storage. Thermal treatments were used as the control applying high temperatures for a short time (HTST 80 °C/30 s) or ultra-high temperature (UHT 130 °C/3 s). UV-C treatments applied to juices with both pHs inactivated coliforms and mesophiles with the same efficacy as thermal treatments. Yeasts and molds were inactivated at a dose of >15.13 mJ/cm² at both pHs. The UV-C doses showed no differences in betalains, polyphenols, or antioxidant activity. However, a decrease in these compounds was observed during storage. The lowest reductions in betacyanins (11.1–16.7%) and betaxanthins (2.38–10.22%) were obtained by UV-C treatment at pH 3.6. Thermal treatments (HTST and UHT) caused a reduction greater than UV-C irradiation in betacyanins, betaxanthins, polyphenols, and antioxidant activity after treatment. However, after storage at pH 3.6, the contents of these compounds reached those of the UV-C treatments, except for polyphenols. In specific pigments, betanin retention was highest at pH 3.6 (62.26–87.24%), and its retention decreases with UV-C dose increase and storage. The indicaxanthin retentions were higher (75.85–92.27%) than those of betanin, and the reduction was mainly due to storage. The physical properties (pH, acidity, and °Brix) were not affected by treatments, except for the color. The results suggest that a dose of 15.13 mJ/cm² of a continuous UV-C system is a non-thermal alternative for the processing of red prickly pear juice at pH 3.6, preserving its properties. Full article

(This article belongs to the Special Issue Non-thermal Technologies for Food Processing)

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Review

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16 pages, 951 KiB

Open AccessReview

Pasteurization of Food and Beverages by High Pressure Processing (HPP) at Room Temperature: Inactivation of Staphylococcus aureus, Escherichia coli, Listeria monocytogenes, Salmonella, and Other Microbial Pathogens

by Filipa Vinagre M. Silva and Evelyn

Appl. Sci. 2023, 13(2), 1193; https://0-doi-org.brum.beds.ac.uk/10.3390/app13021193 - 16 Jan 2023

Cited by 14 | Viewed by 5952

Abstract

Vegetative pathogens actively grow in foods, metabolizing and dividing their cells. They have consequently become a focus of concern for the food industry, food regulators and food control agencies. Although much has been done by the food industry and food regulatory agencies, foodborne [...] Read more.

Vegetative pathogens actively grow in foods, metabolizing and dividing their cells. They have consequently become a focus of concern for the food industry, food regulators and food control agencies. Although much has been done by the food industry and food regulatory agencies, foodborne outbreaks are still reported globally, causing illnesses, hospitalizations, and in certain cases, deaths, together with product recalls and subsequent economic losses. Major bacterial infections from raw and processed foods are caused by Escherichia coli serotype O157:H7, Salmonella enteritidis, and Listeria monocytogenes. High pressure processing (HPP) (also referred to as high hydrostatic pressure, HHP) is a non-thermal pasteurization technology that relies on very high pressures (400–600 MPa) to inactivate pathogens, instead of heat, thus causing less negative impact in the food nutrients and quality. HPP can be used to preserve foods, instead of chemical food additives. In this study, a review of the effect of HPP treatments on major vegetative bacteria in specific foods was carried out. HPP at 600 MPa, commonly used by the food industry, can achieve the recommended 5–8-log reductions in E. coli, S. enteritidis, L. monocytogenes, and Vibrio. Staphylococcus aureus presented the highest resistance to HPP among the foodborne vegetative pathogens investigated, followed by E. coli. More susceptible L. monocytogenes and Salmonella spp. bacteria were reduced by 6 logs at pressures within 500–600 MPa. Vibrio spp. (e.g., raw oysters), Campylobacter jejuni, Yersinia enterocolitica, Citrobacter freundii and Aeromonas hydrophila generally required lower pressures (300–400 MPa) for inactivation. Bacterial species and strain, as well as the food itself, with a characteristic composition, affect the microbial inactivation. This review demonstrates that HPP is a safe pasteurization technology, which is able to achieve at least 5-log reduction in major food bacterial pathogens, without the application of heat. Full article

(This article belongs to the Special Issue Non-thermal Technologies for Food Processing)

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22 pages, 692 KiB

Open AccessReview

Pasteurization of Foods with Ultrasound: The Present and the Future

by Daniela Bermudez-Aguirre and Brendan A. Niemira

Appl. Sci. 2022, 12(20), 10416; https://0-doi-org.brum.beds.ac.uk/10.3390/app122010416 - 15 Oct 2022

Cited by 7 | Viewed by 3528

Abstract

In the last two decades, much research has been carried out using ultrasound as an alternative for pasteurization. Cavitation, the main effect of ultrasound, can disrupt and perforate cell membranes, generate free radicals, and produce sonoluminescence. Ultrasound in combination with additional hurdles such [...] Read more.

In the last two decades, much research has been carried out using ultrasound as an alternative for pasteurization. Cavitation, the main effect of ultrasound, can disrupt and perforate cell membranes, generate free radicals, and produce sonoluminescence. Ultrasound in combination with additional hurdles such as temperature, pressure, or antimicrobials can achieve a 5-log reduction. Pathogens, spoilage microorganisms, yeast, and molds have been successfully inactivated by this novel technology. Currently, ultrasound is investigated as an option to reduce the content of aflatoxins during pasteurization. Ultrasound can inactivate those enzymes related to the stability of pasteurized food products, extending the shelf-life of the products. New uses of sonication are surging; for example, ultrasound has been studied as an option for pasteurizing plant-based foods. An important area of research is ultrasound’s effect on food’s bioactive compounds. Results exhibit an increase in the concentration of phenolics, carotenoids, anthocyanins, and other nutrients after the use of ultrasound because of an extractive effect. Finally, an area of concern in the early ages of ultrasound has been studied, food quality. In most cases, sonicated products have similar quality parameters to raw products. Lastly, there are some areas of opportunity in ultrasound’s future, such as the equipment improvement, regulation, and toxicology of sonicated products. Full article

(This article belongs to the Special Issue Non-thermal Technologies for Food Processing)

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19 pages, 2397 KiB

Open AccessReview

Thermal, High Pressure, and Ultrasound Inactivation of Various Fruit Cultivars’ Polyphenol Oxidase: Kinetic Inactivation Models and Estimation of Treatment Energy Requirement

by Nur Aribah Fatini Zawawi, Nurul Ashikin Md. Hazmi, Muhammad Syahmeer How, Kevin Kantono, Filipa V. M. Silva and Alifdalino Sulaiman

Appl. Sci. 2022, 12(4), 1864; https://0-doi-org.brum.beds.ac.uk/10.3390/app12041864 - 11 Feb 2022

Cited by 18 | Viewed by 4440

Abstract

Polyphenol oxidase (PPO) catalyses the browning reaction during fruit processing and storage. It is considered a threat to clean labels and minimally processed fruit products. Unwanted changes in fruits’ appearance and quality represent a cost to the industry. High pressure and ultrasound, in [...] Read more.

Polyphenol oxidase (PPO) catalyses the browning reaction during fruit processing and storage. It is considered a threat to clean labels and minimally processed fruit products. Unwanted changes in fruits’ appearance and quality represent a cost to the industry. High pressure and ultrasound, in addition to thermal treatment, are effective in reducing PPO activity and producing high-quality products. PPO from different fruit cultivars behaves differently when submitted to different treatments. A systematic review was conducted, where treatment parameters, PPO inactivation data (≥80% inactivation), and kinetic inactivation parameters (rate constant (k), activation energy (Ea), D-value, and z-value) by different treatments were collected. Additionally, the estimated energy requirements for the inactivation of PPO (≥80%) by different treatments were calculated and compared. Resistance to various treatments varies between fruit cultivars. For the same temperature, the inactivation of PPO by ultrasound combined with heat is more effective than thermal treatment alone, and the high pressure combined thermal process. The majority of the thermal, HPP, and ultrasound inactivation of PPO in fruits followed first-order behaviour. Some fruit cultivars, however, showed biphasic inactivation behaviour. The estimated specific energy requirements calculated based on the mass of processed fruit sample to inactivate ≥80% polyphenol oxidase for the thermal process was 87 to 255 kJ/kg, while for high pressure processing it was 139 to 269 kJ/kg and for ultrasound it was 780 to 10,814 kJ/kg. Full article

(This article belongs to the Special Issue Non-thermal Technologies for Food Processing)

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