Quality changes in high hydrostatic pressure treated enriched tomato sauce.

BACKGROUND: Use of high hydrostatic pressure (HHP) with reduced processing times is gaining traction in the food industry as an alternative to conventional thermal treatment. In order to enhance functional benefits while minimizing processing losses, functionalized products are being developed with such novel techniques. In this study, changes in quality parameters for HHP treated enriched tomato sauce were evaluated, with the aim to assess its viability as an alternative to conventional thermal treatment methods. RESULTS: HHP treatments at 500 MPa, 30 °C/50 °C significantly increased the total phenolic and lycopene content of the sauce samples, achieving 6.7% and 7.5% improvements over conventionally treated samples. The antioxidant capacity of the HHP-treated samples was also found to match or be better than conventionally treated samples. Furthermore, a T2 relaxation time study revealed that pressure-temperature processing treatments were effective in maintaining the structural integrity of water molecules. Microbiological analyses revealed that 500 MPa/50 °C 5 min treatment can offer 8 logs reduction colony formation, matching the results of conventional thermal treatment. CONCLUSION: Combined pressure-temperature treatments improve results, reduce time consumption. 500 MPa/50 °C treatments provided retention of quality parameters and significant reduction in microbial activity. © 2024 The Author(s). Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Effects of high hydrostatic pressure on antimicrobial protein stability and the rheological and shelf-life properties of donkey milk.

The effects of high hydrostatic pressure (HHP) and heat treatments on antimicrobial protein stability and on the physico-chemical, microbiological, rheological and shelf-life properties of donkey milk were investigated. Although heat treatment at 75°C for 2 min resulted in 1.50 log CFU ml-1 microbial inactivation, losses in activities of lysozyme (58%) and lactoferrin (82%) were observed due to whey protein denaturation. By contrast, HHP application at 400 MPa caused lower enzyme activity losses (22 and 37% respectively) whilst maintaining a significant reduction of microbial load (1.80 log CFU ml-1). Color analyses showed that the lightness values of all samples decreased during storage. Higher flow consistency (viscosity) and lower flow behavior indexes were observed in heat-treated samples compared to untreated and HHP-treated ones, which can be explained by advanced protein denaturation during heat-treatment. The results suggest that HHP is a more suitable process than heat treatment for preservation of donkey milk within the conditions studied.

Improving the Recovery of Phenolic Compounds from Spent Coffee Grounds (SCG) by Environmentally Friendly Extraction Techniques.

The aim of this study was to investigate and compare the effects of different extraction techniques (high hydrostatic pressure-assisted extraction (HHPE), ultrasound-assisted extraction (UAE), and classical solvent extraction (CSE)) on phenolic compounds from spent coffee grounds (SCG). Different HHPE parameters (300, 400 and 500 MPa at 25 °C for 5, 10 and 15 min) and UAE parameters (40%, 50%, and 60% amplitude at 25 °C for 5, 10 and 15 min) were used. These techniques were compared with CSE (at 50 °C for 30 min) according to total phenolic content (TPC), antioxidant activity (AA), high-performance liquid chromatography (HPLC), scanning electron microscopy (SEM), and infrared (IR) spectroscopy. The results showed that eco-friendly techniques increased the TPC and AA compared to CSE and morphological changes were verified by SEM results. Furthermore, chlorogenic and caffeic acid were also quantified by using HPLC. Chlorogenic acid was found as the main phenolic compound in spent coffee grounds (SCG). The highest chlorogenic acid was detected as 85.0 ± 0.6 mg/kg FW with UAE at 60% amplitude for 15 min. In brief, for the extraction of phenolic compounds from waste SCG eco-friendly techniques such as HHPE and/or UAE were more convenient than CSE.

Time domain (TD)-NMR relaxometry as a tool to investigate the cell integrity of tomato seeds exposed to osmotic stress (OS), ultrasonication (US) and high hydrostatic pressure (HHP).

NMR relaxometry was used to investigate the proton relaxation distribution of the tomato seeds and analyze the damages of the three different processes on the cell membrane integrity of the tomato seed. Tomato seeds were subjected to osmotic stress (OS) (10, 20, 30% NaCl solutions), ultrasonication (US) (5, 10 and 20 min) and high hydrostatic pressure (HHP) (300, 400 and 500 MPa for 15 min at 20 °C). Four peaks were observed in the NMR relaxation spectra of tomato seeds due to multiexponential relation behavior of the plant cell. Each peak corresponds to different water proton compartment within the cell. According to the results, all the three treatments resulted in cell permeabilization and disruption of cellular compartmentalization. Among the treatments, HHP at 500 MPa for 15 min at 20 °C resulted in the most detrimental effect in the cell structure and OS treatment with 10% NaCl solution caused the least changes in the cell structure. In order to further analyze the extent of damage to the cell, tomato seeds exposed to OS, US and HHP were also analyzed by scanning electron microscopy (SEM). These results have demonstrated that NMR relaxometry is a useful tool to investigate the cell integrity of tomato seeds subjected to different treatments.

Effect of high hydrostatic pressure on background microflora and furan formation in fruit purée based baby foods.

The baby foods industry is currently seeking technologies to pasteurize products without formation of processing contaminants such as furan. This work demonstrates the applicability of high hydrostatic pressure (HHP) as a non-thermal decontamination intervention for fruit purée based baby foods. HHP processing was evaluated at 200, 300, and 400 MPa pressures, for 5, 10 and 15 min of treatment times at 25, 35 and 45 °C. HHP application at 400 MPa, 45 °C for 15 min ensured complete inactivation (about 6 log10) of total mesophilic aerophiles, as well as yeasts and molds. No furan was detected in HHP processed products. Thus, the key advantage of HHP over thermal processing is the ability to achieve commercially acceptable microbiological inactivation while avoiding the formation of processing contaminants such as furan.

The impact of UV-C irradiation on spoilage microorganisms and colour of orange juice.

The effect of UV-C irradiation on inactivation of spoilage microorganisms and colour of freshly squeezed orange juice were investigated. Orange juice samples were intentionally fermented in order to increase the natural microflora which were mostly composed of yeasts and then exposed to UV-C irradiation at an intensity level of 1.32 mW/cm(2) and sample depth of 0.153 cm for several exposure times by using a collimated beam apparatus. Applied UV dose was in the range of 0 and 108.42 mJ/cm(2). Resistance of yeast to UV light and existence of suspended particles limited the effectiveness of the process. Survival data obtained for yeasts was either described by the Weibull or traditional first-order model and goodness-of-fit of these models was investigated. Weibull model produced a better fit to the data with higher adjusted determination coefficient (R(2) adj) and lower mean square error (MSE) values which were 0.99 and 0.003, respectively. Time and UV dose of first decimal reduction were obtained as 5.7 min and 31 mJ/cm(2), respectively. The data suggests that biodosimetric studies performed by using inoculated microorganisms for assesment of the efficiency of UV irradiation treatment in the shelf life extension of juices must be carefully evaluated. UV-C irradiation had no influence on the colour of orange juice.

Effect of the High Hydrostatic Pressure Process on the Microbial and Physicochemical Quality of Shalgam.

The processing of shalgam requires the use of an appropriate processing technique due to yeast overgrowth. With advancements in processing technology, high hydrostatic pressure (HHP) as nonthermal and nonchemical preservation has gained attention for its potential. Response surface methodology with the Box-Behnken experimental design was used to make sense of the effects of HHP parameters, namely, pressure (100-500 MPa), temperature (20-40 °C), and time (5-15 min), on microbial and physicochemical factors (pH, total soluble solids, titratable acidity, bioactive compounds, color values). The reduction in the counts of total mesophilic aerobic bacteria, lactic acid bacteria, and yeast-mold increased proportionally with the increase of all pressure levels, application temperatures, and pressurization times (p < 0.05). Stability was maintained in pH, total solubility, and some color parameters such as L*, a*, ΔE, yellow color tone, and red color tone. All findings of the bioactive components (phenolic content, flavonoid content, antioxidant activity, and monomeric anthocyanin content) in the RSM design showed a significant change only in proportion to the square of time (p < 0.05). The optimum pressurization parameter combination of shalgam was determined as a pressure of 367 MPa, temperature of 31.9 °C, and process time of 10.5 min. Under these conditions, values of yeast and mold (Y&M) reduction, total flavonoid content (TFC), total monomeric anthocyanin contents (TMACs), titratable acidity (TA), and reducing sugar content (RSC) were obtained as 4.30 log cfu/mL, 192.89 mg QE/100 mL, 11.88 mg/100 mL, 2.41 glactic acid/L, and 6.78 mg/100 mL, respectively. In particular, the findings in the basic color parameters proved that there was no significant change in the saturated red color of the shalgam. Gallic acid, caffeic acid, chlorogenic acid, catechin, cyanidin-3-O-glucoside, malvidin-3-O-glucoside, and peonidin-3-O-glucoside derivatives are dominant phenolic and anthocyanin compounds, which are frequently found in turnip plants. No important losses in bioactive components were observed, despite changes in pressure and temperature parameters. The HHP method can be suggested to have great potential in the processing of shalgam (fermented turnip beverage) in terms of its ability to maintain the flavors, colors, and nutrients, in addition to ensuring microbiological safety when compared to other preservation methods.

Recovery of phenolic compounds from peach pomace using conventional solvent extraction and different emerging techniques.

The study compared high-pressure, microwave, ultrasonic, and traditional extraction techniques. The following extraction conditions were implemented: microwave-assisted extraction (MAE) at 900 W power for durations of 30, 60, and 90 s; ultrasonic-assisted extraction (UAE) at 100% amplitude for periods of 5, 10, and 15 min; and high-pressure processing (HPP) at pressures of 400 and 500 MPa for durations of 1, 5, and 10 min. The highest yield in terms of total phenolic content (PC) was obtained in UAE with a value of 45.13 ± 1.09 mg gallic acid equivalent (GAE)/100 g fresh weight (FW). The highest PC content was determined using HPP-500 MPa for 10 min, resulting in 40 mg GAE/100 g, and MAE for 90 s, yielding 34.40 mg GAE/100 g FW. The highest value of antioxidant activity (AA) was obtained by UAE in 51.9% ± 0.71%. The PCs were identified through the utilization of Fourier transform infrared (FTIR) spectroscopy and high-performance liquid chromatography (HPLC). Utilizing multivariate analysis, the construction of chemometric models were executed to predict AA or total PC of the extracts, leveraging the information from IR spectra. The FTIR spectrum revealed bands associated with apigenin, and the application of HPP resulted in concentrations of 5.41 ± 0.25 mg/100 g FW for apigenin and 1.30 ± 0.15 mg/100 g FW for protocatechuic acid. Furthermore, HPLC analysis detected the presence of protocatechuic acid, caffeic acid, p-coumaric acid, and apigenin in both green extraction methods and the classical method. Apigenin emerged as the predominant phenolic compound in peach extracts. The highest concentrations of apigenin, p-coumaric acid, and protocatechuic acid were observed under HPP treatment, measuring 5.41 ± 0.25, 0.21 ± 0.04, and 1.30 ± 0.15 mg/kg FW, respectively.

High hydrostatic pressure-assisted extraction of lipids from Lipomyces starkeyi biomass.

The purpose of this study is to evaluate the effect of high hydrostatic pressure (HHP) as a novel approach for yeast cell disruption and lipid extraction from Lipomyces starkeyi DSM 70295 grown in glucose medium (40 g/L and C/N:55/1) at initial pH of 5.0, 25°C, and 130 rpm for 8 days. HHP extraction conditions including pressure, time, and temperature were optimized by response surface methodology. The high speed homogenizer-assisted extraction (HSH) was also used for comparison. The biomass subjected to HHP was examined under scanning electron microscopy and light microscope. A maximal lipid yield of 45.8 ± 2.1% in dry cell basis (w/w) was achieved at 200 MPa, 40°C, and 15 min, while a minimum yield of 15.2 ± 0.9% was observed at 300 MPa, 40°C, and 10 min (p < 0.05). The lipid yield decreased with increasing pressure. It was demonstrated that low pressure (200 MPa) collapsed the cells, while high pressure (400 MPa) created protrusions on the cell wall and cell fragments spread in the environment. This study favors HHP as a promising method for Lipomyces oil extraction. PRACTICAL APPLICATION: Single-cell oils are considered future alternatives to plant-based oils as food additives and dietary supplements. Oleaginous microorganisms accumulate oils in their cell plasma, which makes extraction essential. One of the main obstacles with existing methods is the utilization of strong acids to destroy cell walls. This study aims to demonstrate high hydrostatic pressure as a rapid method for lipid extraction from oleaginous yeast Lipomyces starkeyi.

Inactivation of Escherichia coli and Listeria innocua in kiwifruit and pineapple juices by high hydrostatic pressure.

Escherichia coli and Listeria innocua in kiwifruit and pineapple juices were exposed to high hydrostatic pressure (HHP) at 300 MPa for 5 min. Both bacteria showed equal resistance to HHP. Using low (0 degrees C) or sub-zero (-10 degrees C) temperatures instead of room temperature (20 degrees C) during pressurization did not change the effectiveness of HHP treatment on both bacteria in studied juices. Pulse pressure treatment (multiple pulses for a total holding time of 5 min at 300 MPa) instead of continuous (single pulse) treatment had no significant (p>0.05) effect on the microbial inactivation in kiwifruit juice; however, in pineapple juice pulse treatment, especially after 5 pulses, increased the inactivation significantly (p<0.05) for both bacteria. Following storage of pressure-treated (350 MPa, 20 degrees C for 60 s x 5 pulses) juices at 4, 20 and 37 degrees C up to 3 weeks, the level of microbial inactivation further increased and no injury recovery of the bacteria were detected. This work has shown that HHP treatment can be used to inactivate E. coli and L. innocua in kiwifruit and pineapple juices at lower pressure values at room temperature than the conditions used in commercial applications (>400 MPa). However, storage period and temperature should carefully be optimized to increase the safety of HHP treated fruit juices.

Microbial inactivation and evaluation of furan formation in high hydrostatic pressure (HHP) treated vegetable-based infant food.

The inactivation of pathogenic and spoilage bacteria as well as the formation of food processing contaminants (e.g. acrylamide, furan, etc.) in infant foods is of utmost importance for industry, consumers as well as regulatory bodies. In this study, the potential of high hydrostatic pressure (HHP) for microorganism inactivation including total mesophilic aerobic bacteria (TMA) and total yeasts and molds (TYM) at equivalent processing conditions, as well as its effects on furan formation in vegetable-based infant food was evaluated. The process parameters evaluated were combinations of pressures (200, 300, and 400MPa), temperatures (25, 35, and 45°C), and treatment times (5, 10, and 15min). Pressure, time and temperature had a significant influence on both TMA and TYM inactivation of vegetable-based infant foods, observing a significant reduction in both microbial populations when all the factors were increased, although the extent of reduction was clearly influenced by the type of microorganism. A synergism between pressure, time and temperature was observed for the reduction of both TMA and TYM populations and it was found that HHP at 400MPa resulted in a complete inactivation of TMA as well as TYM after 15min of treatment at 45°C. The furan content in all HHP treated samples was found to be below the limit of detection. Thus, HHP treatment could be considered as a potential alternative to thermal processing of vegetable-based infant foods.

Landmarks in the historical development of twenty first century food processing technologies.

Over a course of centuries, various food processing technologies have been explored and implemented to provide safe, fresher-tasting and nutritive food products. Among these technologies, application of emerging food processes (e.g., cold plasma, pressurized fluids, pulsed electric fields, ohmic heating, radiofrequency electric fields, ultrasonics and megasonics, high hydrostatic pressure, high pressure homogenization, hyperbaric storage, and negative pressure cavitation extraction) have attracted much attention in the past decades. This is because, compared to their conventional counterparts, novel food processes allow a significant reduction in the overall processing times with savings in energy consumption, while ensuring food safety, and ample benefits for the industry. Noteworthily, industry and university teams have made extensive efforts for the development of novel technologies, with sound scientific knowledge of their effects on different food materials. The main objective of this review is to provide a historical account of the extensive efforts and inventions in the field of emerging food processing technologies since their inception to present day.

Technological aspects of horse meat products - A review.

Horse meat and its products can be considered as a food with a high nutritional value. However, due to cases of economically motivated food adulteration by the intentional addition of horse meat beef products in recent years, horse meat has become a controversial issue. Consumer confidence in meat products and the meat industry has diminished, although consumers consider the differences between the food content and the label as the major issue rather than the safety and nutritional characteristics of horse meat. The elaboration of meat products from horse meat (e.g. "cecina", dry-cured loin, salami, bressaola and pâté) is also an interesting alternative to other traditional meat products such as dry-cured pork hams, pork sausages and liver pâtés. In this review, the technological aspects, safety and storage stability of meat products elaborated from horse meat will be addressed by highlighting the nutritional and sensory aspects of these meat products. We aim to improve the existing knowledge about horse meat in the view of recent scandals.

Use of the Weibull model for lactococcal bacteriophage inactivation by high hydrostatic pressure.

Four lactococcal bacteriophages (phiLl6-2, phiLl35-6, phiLd66-36 and phiLd67-42) in M17 broth were pressurized at 300 and 350 MPa at room temperature and their survival curves were determined at various time intervals. Tailing (monotonic upward concavity) was observed in all survival curves. The resulting non-linear semi-logarithmic survival curves were described by the Weibull model and goodness of fit of this model was investigated. Regression coefficients (R2), root mean square error (RMSE), residual and correlation plots strongly suggested that Weibull model produced a better fit to the data than the traditional linear model. Hazard plots suggested that the Weibull model was fully appropriate for the data being analyzed. These results have confirmed that the Weibull model, which is mostly utilized to describe the inactivation of bacterial cells or spores by heat and pressure, could be successfully used in describing the lactococcal bacteriophage inactivation by high hydrostatic pressure.

Salmonella surveillance on fresh produce in retail in Turkey.

Although Turkey is one of the major producers of fruits and vegetables in the world, there has been no information available on the prevalence of pathogens in fresh produce. To fill this gap, we collected 503 fresh produce samples including tomato, parsley, iceberg lettuce, green-leaf lettuce and five different fresh pepper varieties (i.e., green, kapya, bell, mazamort and Charleston) from 3 major districts within 9 supermarkets and 3 bazaars in Ankara, Turkey to investigate the presence of Salmonella. Salmonella was detected in 0.8% (4/503) of samples by conventional culturing method with molecular confirmation conducted through polymerase chain reaction (PCR). For further characterization of isolates, serotyping, antimicrobial susceptibility testing, multi-locus sequence typing (MLST; aroC, thrA, purE, sucA, hisD, hemD and dnaN) and pulsed-field gel electrophoresis (PFGE) were performed. Salmonella enterica subsp. enterica serotypes Anatum, Charity, Enteritidis and Mikawasima were isolated from two parsley, one pepper and one lettuce samples, respectively. MLST resulted in 4 sequence types (STs) for each serotype, including one novel ST for serotype Mikawasima. Similarly, PFGE revealed four different XbaI PFGE patterns. The results of this survey, obtained by the most common subtyping methods (i.e. serotyping, MLST and PFGE) worldwide, contributes to the development of a national database in Turkey, which is essential for investigating the evolutionary pathways, geographical distribution and genetic diversity of Salmonella strains.

Modeling the synergistic effect of high pressure and heat on inactivation kinetics of Listeria innocua: a preliminary study.

The survival curves of Listeria innocua CDW47 by high hydrostatic pressure were obtained at four pressure levels (138, 207, 276, 345 MPa) and four temperatures (25, 35, 45, 50 degrees C) in peptone solution. Tailing was observed in the survival curves. Elevated temperatures and pressures substantially promoted the inactivation of L. innocua. A linear and two non-linear (Weibull and log-logistic) models were fitted to these data and the goodness of fit of these models were compared. Regression coefficients (R2), root mean square (RMSE), accuracy factor (Af) values and residual plots suggested that linear model, although it produced good fits for some pressure-temperature combinations, was not as appropriate as non-linear models to represent the data. The residual and correlation plots strongly suggested that among the non linear models studied the log-logistic model produced better fit to the data than the Weibull model. Such pressure-temperature inactivation models form the engineering basis for design, evaluation and optimization of high hydrostatic pressure processes as a new preservation technique.

Efficiency of high pressure treatment for destruction of Listeria monocytogenes in fruit juices.

The objective of this study was to compare high pressure resistance of Listeria monocytogenes strains at 25 degrees C and 50 degrees C at 350 MPa and to use high pressure (250 MPa and 350 MPa) at 30 degrees C and 40 degrees C for the inactivation of the relatively most pressure resistant strain inoculated in pasteurized apple, apricot, cherry and orange juices. L. monocytogenes CA was found to be the relatively most pressure resistant strain and increasing pressurization from 250 MPa to 350 MPa at 30 degrees C had an additional three to four log cycle reduction in viability, still leaving viable cells after 5 min. When 350 MPa at 40 degrees C for 5 min was applied more than eight log cycle reduction in cell population of all fruit juices was achieved. This study demonstrated that low temperature (40 degrees C) high pressure (350 MPa) treatment has the potential to inactivate relatively pressure resistant L. monocytogenes strains inoculated in different fruit juices within 5 min.

Injury recovery of foodborne pathogens in high hydrostatic pressure treated milk during storage.

Bacteria are expected to be injured or killed by high hydrostatic pressure (HHP). This depends on pressure levels, species and strain of the microorganism and subsequent storage. Injured bacteria may be repaired which could affect the microbiological quality of foodstuffs with an important safety consideration especially in low acid food products. In this study two Gram-positive (Listeria monocytogenes CA and Staphylococcus aureus 485) and two Gram-negative (Escherichia coli O157:H7 933 and Salmonella enteritidis FDA) relatively pressure resistant strains of foodborne pathogens were pressurized at 350, 450 and 550 MPa in milk (pH 6.65) and stored at 4, 22 and 30 degrees C. The results of shelf life studies indicated two types of injury, I1 and I2, for all the pathogens studied. It is obvious that I2 type injury is a major injury and after its repair (I2 to I1), the cells can form colonies on non-selective but not on selective agar. The formation of colonies on both selective and non-selective agar occurs only after full recovery of injury (I1 to AC). The results presented in this study show that even if injured cells are not detected immediately after HHP treatment, I2 type injury could be potentially present in the food system. Therefore, it is imperative that shelf life studies must be conducted over a period of time for potential repair of I2 type injury either to detectable injury (I1) or to active cells (AC) to ascertain microbiological safety of low acid food products.

Evaluation of high hydrostatic pressure sensitivity of Staphylococcus aureus and Escherichia coli O157:H7 by differential scanning calorimetry.

Differential scanning calorimetry (DSC) was used to evaluate the relative high hydrostatic pressure (HHP) resistances of bacterial strains from Staphylococcus aureus and Escherichia coli O157:H7 in vivo. The total apparent enthalpy change and thermal stability were two DSC parameters used to compare bacterial strains of untreated control and pressure-treated bacteria. DSC thermograms indicated that ribosomal denaturation appears to be a major factor in cell death by both thermal and high pressure treatments. However, the analysis of calorimetric data for control samples as well as pressure-treated samples clearly showed that the sensitivities of bacteria to various physical stresses can be different. While S. aureus 765 had a relatively higher resistance to thermal treatment in comparison to S. aureus 485, S. aureus 485 was determined to be more resistant to pressure than S. aureus 765. This information can be utilized in the design of processes specific to targeting certain cellular components by using different physical stresses.

Stress response kinetics of two nisin producer strains of Lactococcus lactis spp. lactis.

The purpose of this study is to determine the survival and nisin production behaviors of two strains of Lactococcus lactis under different stress conditions that represent the food ecosystem. In this respect, the survival ratios of two nisin producers were determined under different pH, temperature, NaCl, and bile salt concentrations. Then, nisin production levels of the strains were determined at each stress conditions. Both strains had similar growth or inactivation patterns under the same stress conditions. NaCl and bile salt stresses on the survival ratio of the strains could be successfully described by the exponential decay function, whereas Gaussian function produced good fits for temperature and pH stresses. The nisin activity of two nisin producers (in their mid-exponential and/or early stationary phase) decreased dramatically under all stress conditions, except osmotic (NaCl) and low temperature applications. The results of this study showed that two nisin producers had similar adaptive responses under severe stress conditions, which could be described by appropriate mathematical equations. Moreover, the effect of harsh environment on the nisin activity of L. lactis strains depends on the stress factors applied.