Thermal Processing of Foods

A special issue of Foods (ISSN 2304-8158).

Deadline for manuscript submissions: closed (28 February 2014) | Viewed by 50974

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Food Nutrition and Packaging Sciences Department, Clemson University, Clemson, SC 29634, USA
Interests: thermal processing; food packaging; probiotics; food engineering and HACCP and sanitation engineering
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

The thermal processing of foods is a very critical area of importance in the commercial production of preserved foods. In order to render processed foods shelf stable, multiple factors need to be considered in order to assure food safety. Our goal is to publish original papers contributing to the knowledge of thermally processed foods. Scientific works to be accepted include but not limited to the following areas: thermo bacteriology, thermal process designs, food packaging of canned foods, food laws and regulations, validations studies in commercial sterilization and pasteurization, and thermal processing methods.

Prof. Dr. Felix Barron
Guest Editor

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Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Foods is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2900 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Published Papers (6 papers)

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Research

1151 KiB  
Article
An Investigation of the Complexity of Maillard Reaction Product Profiles from the Thermal Reaction of Amino Acids with Sucrose Using High Resolution Mass Spectrometry
by Agnieszka Golon, Christian Kropf, Inga Vockenroth and Nikolai Kuhnert
Foods 2014, 3(3), 461-475; https://doi.org/10.3390/foods3030461 - 07 Aug 2014
Cited by 31 | Viewed by 9920
Abstract
Thermal treatment of food changes its chemical composition drastically with the formation of “so-called” Maillard reaction products, being responsible for the sensory properties of food, along with detrimental and beneficial health effects. In this contribution, we will describe the reactivity of several amino [...] Read more.
Thermal treatment of food changes its chemical composition drastically with the formation of “so-called” Maillard reaction products, being responsible for the sensory properties of food, along with detrimental and beneficial health effects. In this contribution, we will describe the reactivity of several amino acids, including arginine, lysine, aspartic acid, tyrosine, serine and cysteine, with carbohydrates. The analytical strategy employed involves high and ultra-high resolution mass spectrometry followed by chemometric-type data analysis. The different reactivity of amino acids towards carbohydrates has been observed with cysteine and serine, resulting in complex MS spectra with thousands of detectable reaction products. Several compounds have been tentatively identified, including caramelization reaction products, adducts of amino acids with carbohydrates, their dehydration and hydration products, disproportionation products and aromatic compounds based on molecular formula considerations. Full article
(This article belongs to the Special Issue Thermal Processing of Foods)
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444 KiB  
Article
Effect of Technological Treatments on Human-Like Leptin Level in Bovine Milk for Human Consumption
by Damiano Magistrelli and Fabia Rosi
Foods 2014, 3(3), 433-442; https://doi.org/10.3390/foods3030433 - 23 Jul 2014
Viewed by 6365
Abstract
In this experiment, raw milk and commercially available full-cream UHT milk, semi-skimmed UHT milk, skimmed UHT milk, full-cream pasteurized milk, semi-skimmed pasteurized milk and infant formulas for babies between 6 and 12 months of age were analyzed by RIA, with a method using [...] Read more.
In this experiment, raw milk and commercially available full-cream UHT milk, semi-skimmed UHT milk, skimmed UHT milk, full-cream pasteurized milk, semi-skimmed pasteurized milk and infant formulas for babies between 6 and 12 months of age were analyzed by RIA, with a method using an antibody directed against human leptin and human leptin as reference standard. Raw milk and full-cream UHT milk did not differ for human-like leptin. Leptin content of full-cream pasteurized milk was not different to that of full-cream UHT milk, but it was 14% lower (p < 0.05) than that observed in raw milk. Human-like leptin level of semi-skimmed UHT milk was not different to that of semi-skimmed pasteurized milk, but it was 30% lower (p < 0.0001) than those of full-cream UHT and full-cream pasteurized milks. In skimmed UHT milk, leptin was 40% lower (p < 0.0001) than in full-cream UHT milk. Leptin was correlated (p < 0.001) with lipid content. Leptin level of infant formulas was not different to that of skimmed milks. Results suggest that the heat treatment (pasteurization or UHT) is not a modifier of human-like leptin content of edible commercial bovine milks, whereas the skimming process significantly reduces milk leptin level. Full article
(This article belongs to the Special Issue Thermal Processing of Foods)
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917 KiB  
Article
Effect of Radio Frequency Heating on Yoghurt, II: Microstructure and Texture
by Caroline Siefarth, Thi Bich Thao Tran, Peter Mittermaier, Thomas Pfeiffer and Andrea Buettner
Foods 2014, 3(2), 369-393; https://doi.org/10.3390/foods3020369 - 20 Jun 2014
Cited by 18 | Viewed by 9197
Abstract
Radio frequency (RF) heating was applied to stirred yoghurt after culturing in order to enhance the shelf-life and thereby meet industrial demands in countries where the distribution cold chain cannot be implicitly guaranteed. In parallel, a convectional (CV) heating process was also tested. [...] Read more.
Radio frequency (RF) heating was applied to stirred yoghurt after culturing in order to enhance the shelf-life and thereby meet industrial demands in countries where the distribution cold chain cannot be implicitly guaranteed. In parallel, a convectional (CV) heating process was also tested. In order to meet consumers’ expectations with regard to texture and sensory properties, the yoghurts were heated to different temperatures (58, 65 and 72 °C). This second part of our feasibility study focused on the changes in microstructure and texture caused by post-fermentative heat treatment. It was shown that there were always microstructural changes with additional heat treatment. Compared to the dense and compact casein network in the stirred reference yoghurt, network contractions and further protein aggregation were observed after heat treatment, while at the same time larger pore geometries were detected. The changes in microstructure as well as other physical and sensorial texture properties (syneresis, hardness, cohesiveness, gumminess, apparent viscosity, G’, G’’, homogeneity) were in good agreement with the temperature and time of the heat treatment (thermal stress). The RF heated products were found to be very similar to the stirred reference yoghurt, showing potential for further industrial development such as novel heating strategies to obtain products with prolonged shelf-life. Full article
(This article belongs to the Special Issue Thermal Processing of Foods)
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835 KiB  
Article
Effect of Radio Frequency Heating on Yoghurt, I: Technological Applicability, Shelf-Life and Sensorial Quality
by Caroline Siefarth, Thi Bich Thao Tran, Peter Mittermaier, Thomas Pfeiffer and Andrea Buettner
Foods 2014, 3(2), 318-335; https://doi.org/10.3390/foods3020318 - 15 May 2014
Cited by 21 | Viewed by 8130
Abstract
This first part of a two-part study focuses on the technical feasibility of applying radio frequency (RF) heating at different temperatures (58, 65 and 72 °C) to a stirred yoghurt gel after culturing. For comparison, a convectional (CV) heating process was also applied. [...] Read more.
This first part of a two-part study focuses on the technical feasibility of applying radio frequency (RF) heating at different temperatures (58, 65 and 72 °C) to a stirred yoghurt gel after culturing. For comparison, a convectional (CV) heating process was also applied. The aim was to increase the yoghurt shelf-life, by preventing post-acidification and the growth of yeasts and molds. At the same time, the viability of lactic acid bacteria (LAB) was investigated in view of existing legal regulations for yoghurts. Additionally, the yoghurt color, aroma and taste profiles were evaluated. It was found that the application of RF heating was effective for the rapid attainment of homogenous temperatures of 58 and 65 °C, respectively. For RF heating at 72 °C, it was not possible to establish a stable heating regime, since in some cases, there was significant overheating followed by strong contraction of the yoghurt curd and whey separation. Hence, it was decided not to continue with the RF heating series at 72 °C. In the case of CV heating, heat transfer limitations were observed, and prolonged heating was required. Nevertheless, we showed that yeasts and molds survived neither the RF nor CV heat treatment. LAB were found not to survive the CV treatment, but these beneficial microorganisms were still present in reduced numbers after RF heating to 58 and 65 °C. This important observation is most likely related to the mildness of RF treatment. While post-acidification was not observed on yoghurt storage, slight color changes occurred after heat treatment. The flavor and taste profiles were shown to be similar to the reference product. Furthermore, a trained sensory panel was not able to distinguish between, for example, the reference yoghurt and the RF 65 °C sample by triangular testing (α = 5%), showing the potential of novel strategies for further improvements of heat-treated yoghurt. Full article
(This article belongs to the Special Issue Thermal Processing of Foods)
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1257 KiB  
Article
Effect of Particle Orientation during Thermal Processing of Canned Peach Halves: A CFD Simulation
by Adreas Dimou, Nikolaos G. Stoforos and Stavros Yanniotis
Foods 2014, 3(2), 304-317; https://doi.org/10.3390/foods3020304 - 08 May 2014
Cited by 18 | Viewed by 7531
Abstract
The objective of this work was to apply Computational Fluid Dynamics (CFD) to study the effect of particle orientation on fluid flow, temperature evolution, as well as microbial destruction, during thermal processing of still cans filled with peach halves in sugar syrup. A [...] Read more.
The objective of this work was to apply Computational Fluid Dynamics (CFD) to study the effect of particle orientation on fluid flow, temperature evolution, as well as microbial destruction, during thermal processing of still cans filled with peach halves in sugar syrup. A still metal can with four peach halves in 20% sugar syrup was heated at 100 °C for 20 min and thereafter cooled at 20 °C. Infinite heat transfer coefficient between heating medium and external can wall was considered. Peach halves were orderly placed inside the can with the empty space originally occupied by the kernel facing, in all peaches, either towards the top or the bottom of the can. In a third situation, the can was placed horizontally. Simulations revealed differences on particle temperature profiles, as well as process F values and critical point location, based on their orientation. At their critical points, peach halves with the kernel space facing towards the top of the can heated considerably slower and cooled faster than the peaches having their kernel space facing towards the bottom of the can. The horizontal can case exhibited intermediate cooling but the fastest heating rates and the highest F process values among the three cases examined. The results of this study could be used in designing of thermal processes with optimal product quality. Full article
(This article belongs to the Special Issue Thermal Processing of Foods)
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671 KiB  
Article
Comparison of the Digestibility of the Major Peanut Allergens in Thermally Processed Peanuts and in Pure Form
by Soheila J. Maleki, David A. Schmitt, Maria Galeano and Barry K. Hurlburt
Foods 2014, 3(2), 290-303; https://doi.org/10.3390/foods3020290 - 07 May 2014
Cited by 21 | Viewed by 8802
Abstract
It has been suggested that the boiling or frying of peanuts leads to less allergenic products than roasting. Here, we have compared the digestibility of the major peanut allergens in the context of peanuts subjected to boiling, frying or roasting and in purified [...] Read more.
It has been suggested that the boiling or frying of peanuts leads to less allergenic products than roasting. Here, we have compared the digestibility of the major peanut allergens in the context of peanuts subjected to boiling, frying or roasting and in purified form. The soluble peanut extracts and the purified allergens were digested with either trypsin or pepsin and analyzed by gel electrophoresis and western blot. T-cell proliferation was measured for the purified allergens. In most cases, boiled and raw peanut proteins were similarly digestible, but the Ara h 1 protein in the boiled extracts was more resistant to digestion. Most proteins from fried and roasted peanuts were more resistant to digestion than in raw and boiled samples, and more IgE binding fragments survived digestion. High-molecular-weight fragments of Ara h1 were resistant to digestion in fried and roasted samples. Ara h 1 and Ara h 2 purified from roasted peanuts were the most resistant to digestion, but differed in their ability to stimulate T-cells. The differences in digestibility and IgE binding properties of the major allergens in roasted, fried and boiled peanuts may not explain the difference between the prevalence of peanut allergy in different countries that consume peanut following these varied processing methods. Full article
(This article belongs to the Special Issue Thermal Processing of Foods)
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