Time-temperature-resolved functional and structural changes of phycocyanin extracted from Arthrospira platensis/Spirulina

Arthrospira platensis, commonly known as Spirulina, gains increasing importance as alternative protein source for food production and biotechnological systems. A promising area is functional high-value algae extracts, rich in phycocyanin, a protein-pigment complex derived from A. platensis. This complex has proven functionality as the only natural blue colorant, fluorescent marker and therapeutic agent. The structure-function relationship is heat sensitive, making thermal processing in its production and its subsequent application a crucial aspect. In continuous high-temperature short-time treatments, it was shown how a purified phycocyanin (mixture of allophycocyanin and c-phycocyanin) disassembled and denatured between 50 and 70 °C. Three characteristic transition temperatures were allocated to specific quaternary aggregates. In contrast to sequential chemical denaturation, phycocyanin's chromophore and protein structure were simultaneously affected by thermal processing. Through a functionality assessment, the findings help optimize the efficiency of raw material usage by defining a processing window, enabling targeted process control resulting in desired product properties.

Understanding water activity change in oil with temperature

Our recent studies and several publications suggest that the low water activity (a_w) of oil in thermal processing might be a major contributing factor towards the increased thermal resistance of bacteria in oils. In this study, we developed a reliable method to measure the water activity of oil by measuring the equilibrium relative humidity in a small headspace. Using this method, water activity of peanut oil was found to decrease exponentially with increasing temperature. A model derived from excess Gibbs free energy was fitted to the observations with an R² = 99.6% and RMSE = 0.01 (a_w). Our results suggest that the sharply reduced water activity of oil resulting from a rise in temperature could cause desiccation of bacteria. This is a possible explanation for the protective effect of oil in thermal processing.

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A method is presented for the measurement of water activity of oil at temperatures up to 85 °C.

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The water activity of peanut oil is found to decrease exponentially as the temperature increases.

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A model is derived to predict the water activity of oil as a function of temperature.

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Desiccation may happen to bacteria in oil during thermal processing, which explains the protective effect of oil.

Factors influencing the release of potentially toxic elements (PTEs) during thermal processing of electronic waste

The release of potentially toxic elements as airborne fine particulates is a significant environmental risk associated with recycling e-waste. Some of these may redeposit near emission sites or be transported over long distances causing wide-spread pollution. With an aim to identify key factors affecting particulate emissions, we report novel investigations on the adsorptive capture of particulate matter (PM) released during low temperature pyrolysis (600 °C; 15 min) of waste printed circuit boards (PCBs). A significant proportion of the released particulates (5.3 to 37%) were captured by adsorbents located downstream and in close proximity to the emitting source. Data was collected for four different PCBs and three adsorbents: alumina, silica-gel and activated carbon. With sizes ranging from nanoparticles to over 10 µm, adsorbed particulates were present as fines, spheres, oblongs, clusters and larger particles with no specific shape. Of the 24 elements identified initially in waste PCBs, only 14 were detected in released particulates: major PTEs- Zn, Sn, Pb and Cu (up to 400 ppm); minor PTEs- Ni, Mn, Cd, Cr and Ba (up to 10 ppm); trace PTEs- Co, In, Bi, Be and Sb (up to 1 ppm). Key factors influencing the release of PTEs during thermal processing were identified as basic elemental characteristics, densities, melting points, vapor pressures, initial concentrations, local bonding and mechanical strength. These results show that the presence of low melting point/high vapour pressure elements (Zn, Pb, Sn) should be minimised for a significant reduction in PTE emissions during e-waste processing.

Physico-chemical characterization of protein fraction from stabilized wheat germ

Wheat germ shows the highest nutritional value of the kernel. It is highly susceptible to rancidity due to high content of unsaturated fat and presence of oxidative and hydrolytic enzymes. In order to improve its shelf life, it is necessary to inactivate these enzymes by a thermal process. In this work the functional properties and some characteristics of the protein fraction of treated wheat germ were evaluated. Sequential extraction of proteins showed loss of protein solubility and formation of aggregates after heating. DSC thermograms showed that wheat germ treated for 20 min at 175 °C reached a protein denaturation degree of ~ 77%. The stabilization process of wheat germ affected significantly some functional properties, such as foaming stability and protein solubility at pH 2 and pH 8. Nevertheless, heating did not affect the water holding, oil holding and foaming capacity of protein isolates.

Effect of process-induced common bean hardness on structural properties of in vivo generated boluses and consequences for in vitro starch digestion kinetics

In the present study, we evaluated the effect of process-induced common bean hardness on structural properties of in vivo generated boluses and the consequences for in vitro starch digestion. Initially, the impact of human mastication on the particle size distribution (PSD) of oral boluses from common beans with different process-induced hardness levels was investigated through a mastication study. Then the effect of structural properties of selected boluses on in vitro starch digestion kinetics was assessed. For a particular process-induced hardness level, oral boluses had similar PSD despite differences in masticatory parameters between participants of the mastication study. At different hardness levels, a clear effect of processing (P<0·0001) was observed. However, the effect of mastication behaviour (P=0·1141) was not significant. Two distinctive fractions were present in all boluses. The first one was a cotyledon-rich fraction consisting of majorly small particles (40-125 µm), which could be described as individual cells based on microscopic observations. This fraction increased with a decrease in process-induced hardness. The second fraction (>2000 µm) mostly contained seed coat material and did not change based on hardness levels. The in vitro starch digestion kinetics of common bean boluses was only affected by process-induced hardness. After kinetic modelling, significant differences were observed between the reaction rate constant of boluses generated from the hardest beans and those obtained from softer ones. Overall this work demonstrated that the in vitro nutritional functionality of common beans is affected to a greater extent by structural properties induced by processing than by mechanical degradation in the mouth.

Crystalline morphology of thermoplastic starch/talc nanocomposites induced by thermal processing

A structural study about the changes induced by plasticization of native corn starch was carried out in this work. The influence of talc nanoparticles presence during starch thermal processing was also evaluated. Macroscopic observation of the granules appearance evolution during melt-mixing and thermo-compression was supported by a theoretical description related to these processing methods. Melt-mixing induced a polymorphic transformation from A- to V_h-type and a reduction in the degree of crystallinity. Homogenous appearance of the plasticized starch was in accordance to the disruption of granules integrity, evidenced by SEM. This observation agreed to the distinctive XRD pattern of plasticized starch from unprocessed granules. Talc incorporation did not require the adjustment of processing parameters in order to obtain a homogenous thermoplastic material, with an adequate particles distribution within the matrix. Regardless talc presence, plasticized starch presented a V_h-type crystalline structure. Thermo-compression led to particles alignment promoted by talc laminar morphology.

Comparative Effects of Thermal, High Hydrostatic Pressure, and UV-C Processing on the Quality, Nutritional Attributes, and Inactivation of Escherichia coli, Salmonella, and Listeria Introduced into Tiger Nut Milk

HIGHLIGHTS

Thermal and nonthermal methods can support a 5-log CFU reduction of model bacteria introduced into tiger nut milk. Thermal treatment of tiger nut milk results in significant loss of protein, antioxidants, and quality properties. HHP or UV-C treatment of tiger nut milk retains quality and nutritional characteristics. HHP or UV-C are suitable for the pasteurization of tiger nut milk.

Brassica-enriched wheat bread: Unraveling the impact of ontogeny and breadmaking on bioactive secondary plant metabolites of pak choi and kale

Consumption of Brassica vegetables is linked to health benefits, as they contain high concentrations of the following secondary plant metabolites (SPMs): glucosinolate breakdown products, carotenoids, chlorophylls, and phenolic compounds. Especially Brassica vegetables are consumed as microgreens (developed cotyledons). It was investigated how different ontogenetic stages (microgreens or leaves) of pak choi (Brassica rapa subsp. chinensis) and kale (Brassica oleracea var. sabellica) differ in their SPM concentration. The impact of breadmaking on SPMs in microgreens (7 days) and leaves (14 days) in pak choi and kale as a supplement in mixed wheat bread was assessed. In leaves, carotenoids, chlorophylls, and phenolic compounds were higher compared to those of microgreens. Breadmaking caused a decrease of SPMs. Chlorophyll degradation was observed, leading to pheophytin and pyropheophytin formation. In kale, sinapoylgentiobiose, a hydroxycinnamic acid derivative, concentration increased. Thus, leaves of Brassica species are suitable as natural ingredients for enhancing bioactive SPM concentrations in bread.

Review on fate of chlorine during thermal processing of solid wastes

Chlorine (Cl) is extensively present in solid wastes, causing significant problems during the thermal conversion of waste to energy or fuels, by combustion, gasification or pyrolysis. This paper introduces the analytical methods for determining the Cl content in solid materials and presents the concentrations of Cl in various types of wastes, as reported in literature. Then, it provides a comprehensive analysis on the Cl emission behavior and Cl species formed during the thermal processing of the inorganic and organic Cl sources. The challenges resulted from the reactions between the formed Cl species and the ferrous metals, the heavy metals and the organic matters are summarized and discussed, e.g., high temperature corrosion, heavy metal evaporation and dioxin formation. The quality degradation of products (oil, char and syngas) by Cl is analyzed. Finally, the available controlling methods of Cl emission, including pre-treatment (water washing, sorting, microwave irradiation and stepwise pyrolysis) and in-furnace (absorbents, co-treatment and catalysts) methods are assessed.

Quantitative and kinetic analyses of peanut allergens as affected by food processing

Peanuts contain four major allergens with differences in allergenic potency. Thermal processing can influence the allergenic properties of peanuts. Until now, a kinetic model has not been reported to assess the changes of soluble allergen (extracted from processed peanuts) content as affected by various thermal processing methods. Our objective is to characterize the reaction kinetics of the thermal processing methods, including wet processing (boiling with/without high-pressure, steaming with/without high-pressure), deep-frying and dry processing (microwaving and roasting) using five time intervals. The relationships between processing time and extractable major allergen content could be explained by a simple linear regression kinetic model (except high-pressure steaming). Among all the methods with optimal processing point, frying for 6 min had a relatively lower IgE binding (linear epitopes) ratio, possibly due to the processing conditions, which caused break down, cross-linking and aggregation of Ara h 2, and a relatively lower solubility.

Edible insects: Cross-recognition of IgE from crustacean- and house dust mite allergic patients, and reduction of allergenicity by food processing

BACKGROUND

Insects have become increasingly interesting as alternative nutrient sources for feeding humans and animals, most reasonably in processed form. Initially, some safety aspects - among them allergenicity - need to be addressed.

OBJECTIVE

To reveal the cross-reactivity of shrimp-, mite- and flies-allergic patients to different edible insects, and further to assess the efficacy of food processing in reducing the recognition of insect proteins by patients' IgE and in skin prick testing of shrimp-allergic patients.

METHODS

IgE from patients allergic to crustaceans, house dust mite or flies was evaluated for cross-recognition of proteins in house cricket Acheta domesticus (AD), desert locust Schistocerca gregaria (SG) and Yellow mealworm Tenebrio molitor (TM). Changes in IgE-binding and SPT-reactivity to processed insect extracts were determined for migratory locust (Locusta migratoria, LM), after different extraction methods, enzymatic hydrolysis, and thermal processing were applied.

RESULTS

IgE from patients with crustacean-allergy shows cross-recognition of AD, SG and stable flies; house dust mite allergics' IgE binds to AD and SG; and the flies-allergic patient recognized cricket, desert locust and migratory locust. Cross-reactivity and allergenicity in SPT to LM can be deleted by conventional processing steps, such as hydrolysis with different enzymes or heat treatment, during the preparation of protein concentrates.

CONCLUSION

The results show that crustacean-, HDM- and stable flies-allergic patients cross-recognize desert locust and house cricket proteins, and crustacean-allergic patients also flies proteins. Furthermore, this study shows that appropriate food processing methods can reduce the risk of cross-reactivity and allergenicity of edible insects.

Hydrophobicity and aggregation, but not glycation, are key determinants for uptake of thermally processed β-lactoglobulin by THP-1 macrophages

The aim of this study is to investigate the immunological relevance of modifications of food protein structure due to thermal processing. We investigated the uptake of β-lactoglobulin, treated with 3 different processing methods, by THP-1 macrophages: wet heating (60 °C in solution) and high- or low-temperature (130 °C or 50 °C, respectively) dry heating, combined with either of 8 types of saccharides or without saccharide. The processing method that was applied significantly affected the uptake of BLG by THP-1 macrophages, while the type of saccharide only had an influence in high-temperature dry heated samples. A set of physicochemical parameters of processed samples was determined, to determine the samples' molecular weight, hydrophobicity, amyloid-like structure, surface charge and secondary structure. Analysis of protein structure alterations indicated the uptake to be linked to the wet heating processing method and percentage of α-helix structure, amyloid-like structures, polymers, and hydrophobicity. We hypothesize that both amyloid-like structures and molecular weight were related to the increased hydrophobicity and therefore postulate that the exposure of hydrophobic regions is the leading physicochemical characteristic for the observed uptake of wet heated BLG samples by THP-1 macrophages. This work demonstrates how differential thermal processing of foods, through protein modification, can have an impact on its interaction with the immune system.

Determination of food allergens by LC-MS: Impacts of sample preparation, food matrix, and thermal processing on peptide detectability and quantification

Food allergies are a growing worldwide concern and the contamination of products with food allergens represents a significant health risk to allergic consumers. With the introduction of reference doses, quantitative methods are needed for the monitoring of allergen levels, and the potential of LC-MS/MS is of hugely growing interest. In this study, we demonstrate that relevant food matrices (bakery products and chocolates) and thermal food processing substantially influence the quantification of 18 marker peptides from various nut and peanut allergens via targeted proteomics. In addition, we characterize the individual release kinetics of marker peptides and provide examples for metastable marker peptide candidates. Matrix recovery rates overall ranged between 15 and 250% with the observed variation being linked to the individual peptide structure as well as to specific matrix interferences. In contrast, thermal processing considerably influences the detectability of allergens on the protein level as different marker peptides from the identical parent allergen are similarly affected, leading to a loss in signal of up to 83% in extreme cases after a 45-min simulated baking. Provided data are finally used for evaluation of different calibrators as well as the overall potential and challenges of LC-MS for the absolute quantification of food allergens. SIGNIFICANCE: With the scientific discussion moving towards a risk-based management of food allergens, including the establishment of threshold doses, robust methods for the absolute quantification of allergens in food samples are urgently needed. Because the currently used antibody- and DNA-based technologies show severe limitations in terms of specificity and reproducibility, LC-MS has emerged as a promising alternative. Its application to absolute quantification, however, first requires an understanding of the various impacts that affect quantification results, including different food matrices, sample preparation, and thermal processing of foodstuffs. Knowledge of these factors, which are assessed as part of a comprehensive survey in this study, is also an important prerequisite to evaluate means of calibration for an LC-MS-based quantification of food allergens.

Physical and thermal processing of Waste Printed Circuit Boards aiming for the recovery of gold and copper

The recovery of electronic waste to obtain secondary raw materials is a subject of high relevance in the context of circular economy. Accordingly, the present work relies on the evaluation of mining separation/concentration techniques (comminution, size screening, magnetic separation and gravity concentration) alone as well as combined with thermal pre-treatment to recover gold and copper from Waste Printed Circuit Boards. For that purpose, Waste Printed Circuit Boards were subjected to physical processing (comminution, size screening in 6 classes from <0.425 mm to > 6.70 mm, magnetic separation and gravity concentration) alone and combined with thermal treatment (200-500 °C), aiming the recovery of gold and copper. Mixed motherboards and graphic cards (Lot 1 and 3) and highly rich components (connectors separated from memory cards, Lot 2) were analyzed. Gold and copper concentrations were determined before and after treatment. Before treatment, concentrations from 0.01 to 0.6 % wt. and from 9 to 20 % wt. were found for gold and copper respectively. The highest concentrations were observed in the size fractions between 0.425 and 1.70 mm. The highest copper concentration was around 35 % wt. (class 0.425-0.85 mm) and when analyzing memory card connectors alone, gold concentrations reached almost 2% in the same class, reflecting the interest of separating such components. The physical treatment alone was more effective for Lot 1/3, compared to Lot 2, allowing recoveries of 67 % wt. and 87 % wt. for gold and copper respectively, mostly due to differences in particles size and shape. The thermal treatment showed unperceptive influence on gold concentration but significant effect for copper concentration, mostly attributed to the size of the copper particles. Concentrations increased in a factor of around 10 when the thermal treatment was performed at 300 °C for the larger particles (1.70-6.70 mm); the best results were obtained at 400 °C for the other sizes, when the highest rate of thermal decomposition of the material occurred.

Profiling the impact of thermal processing on black raspberry phytochemicals using untargeted metabolomics

Clinical and laboratory studies have implicated black raspberries (BRBs) and their associated phytochemicals in the modulation of several chronic diseases. Most research on the health benefits of BRBs is conducted using freeze-dried or otherwise minimally processed products, yet BRBs are typically consumed as thermally processed goods like jams and syrups. The objective of this work was to profile the chemical changes that result from thermal processing of BRB powder into a nectar beverage. Using an untargeted UHPLC-QTOF-MS metabolomics approach, key degradation products of anthocyanins were identified along with several other proposed phenolic degradants. The effects of processing on other key BRB compound groups, including ellagitannins, are also discussed. This work demonstrates the utility of an untargeted metabolomics approach in describing the chemistry of complex food systems and provides a foundation for future research on the impact of processing on BRB product bioactivity.

Effect of various food processing and handling methods on preservation of natural antioxidants in fruits and vegetables

Bioactive compounds from plant sources are generally categorized as natural antioxidants with well-known health benefits. The health-promoting characteristics of natural antioxidants include anti-inflammatory, anti-diabetic, and hepatic effects as well as free radical scavenging. Herein, a comprehensive and comparative review are presented about the effects of conventional (thermal and mechanical) and relatively new (non-thermal) processing methods on phytochemicals and discussed the importance of implementing the use of those methods that could be of very helpful retaining the quality of the bioactive compounds in plant-based foods. Plant-based foods rich in phenolics, vitamin C, carotenoids, and other compounds undergo a range of processing operations before they are consumed. Most of these methods involve thermal treatments of fruits, stems, leaves, and roots. These techniques have varying effects on bioactive compounds and their activities, and the magnitude of these effects depends on process parameters such as temperature, time, and the food matrix. Thermal processing can be detrimental to bioactive compounds while nonthermal procedures may not cause significant deterioration of important health-promoting phytochemicals and in some cases can improve their bio-activity and bio-availability. The detrimental effects of conventional processing on the quality of natural antioxidants have been compared to the effects of innovative nonthermal food treatments such as gamma and ultraviolet irradiation, ultraviolet light, pulsed electric fields, and high hydrostatic pressure.

Effects of thermal and non-thermal processing of cruciferous vegetables on glucosinolates and its derived forms

Brassica vegetables, which include broccoli, kale, cauliflower, and Brussel sprouts, are known for their high glucosinolate content. Glucosinolates and their derived forms namely isothiocyanates are of special interest in the pharmaceutical and food industries due to their antimicrobial, neuroprotective, and anticarcinogenic properties. These compounds are water soluble and heat-sensitive and have been proved to be heavily lost during thermal processing. In addition, previous studies suggested that novel non-thermal technologies such as high pressure processing, pulsed electric fields, or ultraviolet irradiation can affect the glucosinolate content of cruciferous vegetables. The objective of this paper was to review current knowledge about the effects of both thermal and non-thermal processing technologies on the content of glucosinolates and their derived forms in brassica vegetables. This paper also highlights the importance of the incorporation of brassica vegetables into our diet for their health-promoting properties beyond their anticarcinogenic activities.

Boiling and Pressure Cooking Impact on IgE Reactivity of Soybean Allergens

BACKGROUND

Soybean is one of the 8 foods that causes the most significant rate of food allergies in the USA and Europe. Thermal processing may impact on the allergenic potential of certain foods. We aimed to investigate modifications of the IgE-binding properties of soybean proteins due to processing methods that have been previously found to impact on the allergenicity of legumes such as peanut.

METHODS

Soybean seeds were subjected to different thermal processing treatments. To evaluate their impact on the IgE-binding capacity of soybean proteins, individual sera from 25 patients sensitized to soybean were used in in vitro immunoassays. Detection of specific soybean allergens in untreated and treated samples was carried out with specific monoclonal and polyclonal antibodies. In vivo studies of skin prick testing (SPT) were also performed.

RESULTS

The IgE reactivity of soybean was resistant to boiling up to 30 min, and this treatment had a higher impact when applied for 60 min. Treatment that combined heat and pressure produced a fragmentation of proteins in both soluble and insoluble fractions that went along with a decreased capacity to bind IgE and reduced the SPT wheal size. However, allergens such as 7S globulins survived this treatment.

CONCLUSIONS

Thermal-processing methods able to attenuate the capacity of soybean proteins to bind IgE may contribute to the improvement of food safety and could constitute a potential strategy for the induction of tolerance to soybean.

Targeting the middle region of CP4-EPSPS protein for its traceability in highly processed soy-related products

Transgenic components in genetically modified organisms consist not only of the transgenic genes, but also the transgenic protein. However, compared with transgenic DNA, less attention has been paid to the detection of expressed protein, especially those degraded from genetically modified soybean after food processing. In this study, the full length 5-enolpyruvyl-shikimate-3-phosphate synthase (CP4-EPSPS, 47.6 kD) protein was probed with the SC-16 (S19-R33) and the DC-16 (D219-K233) polyclonal antibodies in immunoblots. Both antibodies were able to detect the full length CP4-EPSPS and its residues in soy powder made from Roundup-Ready soybeans after heating and microwaving treatments which also reduced the molecular weight of the protein to 45.8 and 38.7 kD, respectively. Taken together the immunoblot results suggest that the middle region of the CP4-EPSPS protein possessed better stability than its N-terminal during thermal processing. This deduction was further validated by autoclave treatment, where a 37.4 kD residue of the protein was recognized by DC-16. A similar result was obtained in processed smoked sausage containing Roundup Ready soybean protein isolate (as an extender). The additional use of a further polyclonal antibody CK-17 (C372-K388), showed that compared with only the one signal for CP4-EPSPS detected by the SC-16 and CK-17 antibodies, the DC-16 middle region antibody detected four signals for CP4-EPSPS from five market sourced soy protein concentrates. Taken together, the study suggested that the middle region of CP4-EPSPS was more useful than the N- and C-terminal for tracing transgenic CP4-EPSPS protein and its remnants in highly processed soy-related products.

Survival of porcine epidemic diarrhea virus (PEDV) in thermally treated feed ingredients and on surfaces

BACKGROUND

Infection with Porcine Epidemic Diarrhea Virus (PEDV) causes vomiting, diarrhea, and dehydration in young pigs. The virus made its first appearance in the U.S. in 2013, where it caused substantial neonatal mortality and economic losses in the U.S. pork industry. Based on outbreak investigations, it is hypothesized that the virus could be transmitted through contaminated feed or contaminated feed surfaces. This potential risk created a demand for research on the inactivation kinetics of PEDV in different environments. Therefore, the objective of this study was to evaluate the survival of PEDV in 9 different feed ingredients when exposed to 60, 70, 80, and 90 °C, as well as the survival on four different surfaces (galvanized steel, stainless steel, aluminum, and plastic).

RESULTS

Overall, there were no differences (P > 0.05) in virus survival among the different feed matrices studied when thermally processed at 60 to 90 °C for 5, 10, 15, or 30 min. However, the time necessary to achieve a one log reduction in virus concentration was less (P < 0.05) when ingredients were exposed to temperatures from 70 °C (3.7 min), 80 °C (2.4 min), and 90 °C (2.3 min) compared with 60 °C (4.4 min). The maximum inactivation level (3.9 log) was achieved when heating all ingredients at 90 °C for 30 min. There were no differences in the amount of time necessary to cause a one log reduction in PEDV concentration among the different surfaces.

CONCLUSIONS

The results of this study showed that PEDV survival among the 9 feed ingredients evaluated was not different when exposed to thermal treatments for up to 30 min. However, different combinations of temperature and time resulted in achieving a 3 to 4 log reduction of PEDV in all feed ingredients evaluated. Finally, PEDV survival was similar on galvanized steel, stainless steel, aluminum and plastic.

Validation of Thermal Lethality against Salmonella enterica in Poultry Offal during Rendering

Recent outbreaks of human disease following contact with companion animal foods cross-contaminated with enteric pathogens, such as Salmonella enterica, have resulted in increased concern regarding the microbiological safety of animal foods. Additionally, the U.S. Food and Drug Administration Food Safety Modernization Act and its implementing rules have stipulated the implementation of current good manufacturing practices and food safety preventive controls for livestock and companion animal foods. Animal foods and feeds are sometimes formulated to include thermally rendered animal by-product meals. The objective of this research was to determine the thermal inactivation of S. enterica in poultry offal during rendering at differing temperatures. Raw poultry offal was obtained from a commercial renderer and inoculated with a mixture of Salmonella serovars Senftenberg, Enteritidis, and Gallinarum (an avian pathogen) prior to being subjected to heating at 150, 155, or 160°F (65.5, 68.3, or 71.1°C) for up to 15 min. Following heat application, surviving Salmonella bacteria were enumerated. Mean D-values for the Salmonella cocktail at 150, 155, and 160°F were 0.254 ± 0.045, 0.172 ± 0.012, and 0.086 ± 0.004 min, respectively, indicative of increasing susceptibility to increased application of heat during processing. The mean thermal process constant (z-value) was 21.948 ± 3.87°F. Results indicate that a 7.0-log-cycle inactivation of Salmonella may be obtained from the cumulative lethality encountered during the heating come-up period and subsequent rendering of raw poultry offal at temperatures not less than 150°F. Current poultry rendering procedures are anticipated to be effective for achieving necessary pathogen control when completed under sanitary conditions.

Changes in ginsenoside patterns of red ginseng extracts according to manufacturing and storage conditions

Although the pharmacological action of red ginseng is mostly generated by ginsenosides, contents of ginsenosides in manufactured extracts are still varying according to processing and storage conditions. Rg1, Rb1, and Rh1 levels significantly decreased overtime under pH adjustment and thermal treatment during storage, and these changes were exacerbated at lower pH and higher storage temperature. However, Rg3 level showed the opposite pattern compared to other ginsenosides. Rg3 level linearly increased at higher temperature and pH while significantly decreased at pH 2. Furthermore, Rg3 level constantly increased during storage. This is the first combined study on the effects of manufacturing and storage conditions on ginsenoside contents of red-ginseng-extract products. To minimize loss of major marker and bioactive compounds of red ginseng products during manufacturing processes and storage, it is recommended that red-ginseng-extracts be maintained at pH 6-8, sterilized at below 105 °C, and stored at below 25 °C.

Ascorbic acid stability in fruit juices during thermosonication

Thermosonication is an emerging technology useful for inactivating microorganisms and enzymes in fruit juices. However, the effect of the ultrasound processing on the ascorbic acid content is not clear and the results reported in the literature are contradictory. In this work, the impact of sonication and thermosonication on the ascorbic acid content was first evaluated in model systems. Degassed model solutions at four different pH values (3-6) were processed with or without sonication for 60min at two different conditions of temperature (25 and 55°C). In all cases, the ascorbic acid was stable under the treatment. After that, two commercial deaerated fruit juices were processed with and without US at 55°C. The ascorbic acid was also retained in these juices after the ultrasound processing under the most severe conditions studied. In conclusion, previous degassing/deaerating of fruit juices is recommended to prevent ascorbic acid degradation when thermosonication is applied.

Kinetic study of furan and furfural generation during baking of cake models

This study describes the kinetics of furan and furfural generation in a cake model, for the first time. These process-induced compounds impact safety and sensory aspects of baked products. Understanding their generation with regards to process dynamics will serve food quality design. However, the complexity of real products makes this task challenging. This work provides a novel approach to understand and model chemical reactivity by implementing an inert cake model (starch, water and cellulose), specifically designed for mimicking a sponge cake structure. The addition of reaction precursors (glucose and leucine) to follow Maillard and caramelization reactions, resulted in browning and generated considerable levels of furanic compounds (up to 17.61ng/g for furan and 38.99μg/g for furfural, dry basis). Multiresponse data modeling resulted in a kinetic model which adequately describes experimental concentrations and makes it possible to estimate the degradation of precursors and the behavior of two hypothetic intermediates.

Retorting conditions affect palatability and physical characteristics of canned cat food

The effects of different temperature and time conditions during retorting of canned cat food on physicochemical characteristics and palatability were examined. For this purpose, lacquer cans containing an unprocessed loaf-type commercial cat food were heated in a pressurised retorting system at three specified temperature–time profiles (113°C/232 min, 120°C/103 min and 127°C/60 min) to equal a similar lethality (F₀ value = 30). Physicochemical properties (viscosity, texture, particle size, pH) were determined, and a 10 d three-bowl palatability test was performed with ten European shorthair cats. Retorting at 113°C/232 min resulted in differences in all the physical parameters examined (<viscosity, firmness, adhesiveness, and > particle size). Significant pH differences were observed (6·53, 6·63 and 6·66 for T113/232, 120 and 127°C, respectively). Preference ratios were 0·38, 0·31 and 0·31 for T113/232, 120 and 127°C, respectively (P = 0·067). It can be concluded that different retorting temperature–time profiles with equal F₀ value significantly affect physical characteristics and tended to affect palatability of moist cat food.