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Moderately processed surimi products exhibit better nutrient retention and enhanced gels, and the great potential of microwaves application and changes in the way of chopping meat has been reported by previous research. In this study, a systematic analysis of the novel surimi product was made to explore the heat and mass transfer characteristics. A porous media model combining electromagnetic heat and hygroscopic expansion was developed to evaluate this process, and its accuracy has been verified experimentally. It was found that the dielectric characterization of multiphase mixture system has great influence on the results, the complex refractive index mixture equation was used due to its lowest root-mean-square error value. In addition, the effect of moderate processing on microwave heating was examined in terms of porosity changes. However, nonuniform temperature distributions were found in the higher porous samples, especially when the porosity is greater than 0.81. Moreover, the developed model was coupled with the evaluation for gel properties and the results showed the significant effect of moderate crushing on the gel quality during the microwave heating process.

To provide an insight into the oxidation behavior of cysteines in myofibrillar proteins (MPs) during microwave heating (MW), a quantitative redox proteomic analysis based on the isobaric iodoacetyl tandem mass tag technology was applied in this study. MPs from silver carp muscles were subjected to MW and water bath heating (WB) with the same time-temperature profiles to eliminate the thermal differences caused by an uneven energy input. Altogether, 422 proteins were found to be differentially expressed after thermal treatments as compared to that with no heat treatment. However, MW triggered a larger number of proteins and cysteine sites for oxidation. Myosin heavy chain, myosin-binding protein C, nebulin, α-actinin-3-like, and titin were found to be highly susceptible to oxidation under microwave irradiation. Notably, MW caused such modifications at cysteine site 9 in the head of myosin, revealing the enhancement mechanism of MP gelation by excess cysteine cross-linking during microwave processing. Furthermore, Gene Ontology and functional enrichment analyses suggested that the two thermal treatments resulted in some differences in ion binding, muscle cell development, and protein-containing complex assembly. Overall, this study is the first to report the redox proteomic changes caused by MW and WB treatments, thus providing a further understanding of the microwave-induced oxidative modifications of MPs.

Background Recently, fatty fish have been utilized as a potential approach for the fabrication of surimi products, with the yield of fatty fish surimi being > 10 000 tons in 2019. However, the gelling properties of catfish surimi can be influenced by intermuscular lipid. Lipase could effectively enhance the gel quality of catfish surimi gels, although the chemical forces involved in gel formation and alteration in lipid and protein oxidation status are not well understood. The present study investigated the gelation-enhancing effects of lipase on catfish surimi based on changes in chemical oxidation interactions. Results The addition of 7.5 g kg-1 lipase significantly increased the hydrophobic interactions and disulfide bond contents, both of which facilitated gel formation, in surimi gels. The 2-thiobarbituric acid reactive substance and carbonyl concentrations demonstrated that lipase promoted lipid and protein oxidations. Furthermore, an appropriate dose of malondialdehyde accelerated protein oxidation, thereby resulting in the covalent cross-linking of proteins. Consequently, the gel strength increased from 55.72 to 127.71 g × cm with lipase contents of up to 7.5 g kg-1 , and strong chemical cross-linking and a compact network were observed via sodium dodecyl sulfate polyacrylamide gel electrophoresis and scanning electron microscopy. However, excessive oxidation led to the degeneration of the gel matrix. A schematic mechanism, mainly based on the chemical changes, is proposed. Conclusion The present study revealed the gelation mechanism of catfish surimi gels with lipase, and suggested that lipase treatments may be an effective approach for improving the textural properties of fatty fish surimi gels. © 2021 Society of Chemical Industry.

The objective of this work was to investigate the cryoprotective effects of antifreeze peptides obtained from silver carp scales (ScAFPs) on the freeze-thaw stability of surimi, and to explore the action mechanisms of ScAFPs on frozen surimi. The comprehensive analysis of ice crystal size, myofibril protein oxidation, water retention, surimi gel properties, and rheological properties of surimi after different freeze-thaw cycles were investigated. Results showed that frozen surimi treated with ScAFPs exhibited a higher Ca

The effects of freeze-thaw (F-T) cycles on the shape retention of antifreeze peptides-based surimi ink (ASI) 3D structures were analyzed. The results showed that the ASI 3D structure has good shape retention ability, and the width, height, weight, and water holding capacity were 22.42 mm, 21.07 mm, 9.99 g, and 68.30 % even after F-T 4 times, respectively. The average area and equivalent diameter of ice crystals in ASI 3D structures only expand from 0.001 mm

Freeze denaturation of protein caused by ice crystals is the main motivation for the quality deterioration of surimi during circulation and storage. This investigation aimed to cryoprotect surimi by adding antifreeze peptides from Takifugu obscurus skin (TsAFP) which can inhibit ice recrystallization, and to elucidate regulating mechanism. The comprehensive results showed that 4% TsAFP, half dosage of commercial cryoprotectant, had good cryoprotection on surimi by reducing the moisture variation and maintaining protein solubility of surimi at macro level, as well as inhibiting the degeneration and structure changes of myofibrillar proteins at micro level. Meanwhile, TsAFP could directly bind to the structural cavity of myosin, inhibit protein freezing-induced oxidation, maintain the spatial structure of myosin and water retention ability to preserve the surimi quality. This study helped better comprehend the protective mechanisms of antifreeze peptides in frozen surimi and was expected to provide a promising cryoprotectant for low-sweetness and low-calorie surimi.

Soybean protein pastes were preheated for different times (20, 25 and 30 min) with l-cysteine to improve the printability and self-gelation properties and to explore the relationship between the degree of denaturation and the feasibility of microwave 3D printing. As the pre-denaturation degree increased, ordered secondary structures in proteins gradually decreased, and tertiary structures unfolded. Soybean protein printability, moulding quality increased, and soybean protein, which is not suitable for printing in its natural state, achieved self-gelling after 3D printing. Soybean protein pastes preheated for 25 min with l-cysteine achieved a complete hollow sphere structure compared to other formulations, while pastes preheated for 30 min formed a coarser structure, and blockage occurred during printing. The covalent bond of ε- (γ-glutamine) formed by the synergistic effect of transglutaminase (TGase) and microwaves was the main force driving the gel network structure formation. The most suitable pre-denaturation degree of soybean protein was quantitatively characterized as 57 %.

The aim of this work was to investigate the role of microwave on myosin aggregation during different heating process and to explore the potential relationship between conformation changes and physicochemical properties of myosin. Microwave heating lead to the increasing of turbidity of myosin, but this result was largely influenced by the temperature. Surface hydrophobicity were the dominant binding forces in the formation of myosin aggregation. However, the disulfide bonds play a much more important role in the protein aggregation forming in heat treatment at 60 and 90 °C. Circular dichroism revealed that microwave heating considerably altered the secondary structure of myosin. The gradual disappearance of negative peaks at 202 and 222 nm indicated that a significant decrease in α-helix formation. Particle size distribution and atomic force microscopy analyses demonstrated a more rapid myosin aggregation in response to the microwave treatment at 60 and 90 °C. These results helps to better understand the gel formation mechanism of surimi under microwave field and to improve myosin-based food quality by using microwave treatment.

To better apply microwave technology to surimi industry, surimi gels of different thicknesses were investigated. According to the determination of electromagnetic properties of surimi paste, both the maximum penetration depth and absorption peak are less than 1 cm. The results of temperature distribution shown that the highest temperature point of the surimi shifted from the center to the periphery. The coefficient of variation (COV) was the minimum and the temperature distribution the temperature distribution was the most uniform when the surimi thickness was 2.0 cm. Surimi paste with a thickness of 2.0 cm heated by microwaves (2450 MHz) had higher gel properties (16.42 ± 0.22 MPa) and water holding capacity (73.59 ± 0.26%) compared to that heated by the traditional water bath method. Scanning electron microscopy revealed that an ordered and dense network structure formed at a thickness of 2 cm. The optimum thickness (2 cm) for microwave heating was determined based on the electromagnetic characteristics and the temperature distribution of surimi, which provided basis for the application of microwave in surimi products.

To preserve the quality of frozen food products, the main goal of suitable thawing is to cause the least amount of damage with the shortest possible thawing time. A radiofrequency (RF) system has potential for use in achieving these goals for industrial thawing operations. This study investigated the characteristics of RF thawing, and sought to determine the optimal conditions for RF thawing by clarifying the temperature distributions in blocks of frozen minced fish. The dielectric properties (DPs) of frozen minced fish and the penetration depths (dp) of thawing were measured under differing methods and conditions. The temperatures measured by the probes were plotted in Surfer and verified by COMSOL simulation. A sharp increase in DPs (e′ and e″) was observed at a frequency of 27.12 MHz (from −3 °C to 0 °C), and a striking dp was found from −15 °C to −5 °C, Electromagnetic waves at this frequency could penetrate our samples easily, and the uniformity of heating was improved at both ranges of temperature. For the size of frozen minced fish blocks that are commonly used in the industry (25 × 15 × 5 cm), the most suitable electrode gap for thawing was found to be 16 cm. Unlike in the results obtained with other thawing methods, the cooked gel properties after RF thawing were unaffected, which proved that the RF system is optimal for use in industrial production.

Chilled surimi has become increasingly popular owing to its superior texture and freshness. In this study, changes in the microbiota and gel properties during chilled surimi storage, and the contributions of dominant bacteria to the physicochemical properties of chilled surimi were investigated. The results showed that Pseudomonas gessardii, Aeromonas media, and Acinetobacter johnsonii were the dominant bacteria during chilled surimi storage. P. gessardii was the key bacteria that degraded protein in the process of surimi spoilage, which led to high total volatile base nitrogen (TVB-N), trichloroacetic acid (TCA)-soluble peptides as well as poor gel properties. Both P. gessardii and A. media were high putrescine producers, whereas only A. media produced cadaverine. In this study, spoilage microorganisms in chilled surimi were investigated for the first time, and it was found that P. gessardii had the greatest influence on surimi quality, which provides a research basis for in-depth study on the mechanism of microbial spoilage and the preservation of chilled surimi.

Antifreeze peptides regulate the physiological functions of frozen cells and even their apoptosis; however, the mechanisms by which antifreeze peptides regulate these processes remain unclear, although the interactions between cell membranes and ice are well known to be important in this process.Our study aims to investigate how antifreeze peptides regulate cell physiological functions during the freezing process.We investigated the cryoprotective effect of rsfAFP on the physiological functions of S. thermophilus under freezing stress by measuring cellular metabolism activity, intracellular enzyme activity, cell membrane characterization, and cell apoptosis. The mechanism by which rsfAFP impacts S. thermophilus physiological functions under freezing stress was investigated using multispectral techniques and cryo-TEM.We show that a recombinant antifreeze peptide (rsfAFP) interacts with the extracellular capsular polysaccharides and peptidoglycan of Streptococcus thermophilus and ice to cover the outer layer of the membrane, forming a dense protective layer that regulates the molecular structure of extracellular ice crystals, which results in reduced extracellular membrane damage, depressed apoptosis and increased intracellular metabolic activity. This interaction mechanism was indicated by the fact that S. thermophilus better maintained its permeability barrier, membrane fluidity, membrane structural integrity, and cytoplasmic membrane potential during freezing stress with rsfAFP treatment.These results provide new insights into the mechanism by which rsfAFP regulates frozen cellphysiological functionsand apoptosis under freezing stress.

To provide an insight into the oxidation behavior of cysteines in myofibrillar proteins (MPs) during microwave heating (MW), a quantitative redox proteomic analysis based on the isobaric iodoacetyl tandem mass tag technology was applied in this study. MPs from silver carp muscles were subjected to MW and water bath heating (WB) with the same time-temperature profiles to eliminate the thermal differences caused by an uneven energy input. Altogether, 422 proteins were found to be differentially expressed after thermal treatments as compared to that with no heat treatment. However, MW triggered a larger number of proteins and cysteine sites for oxidation. Myosin heavy chain, myosin-binding protein C, nebulin, α-actinin-3-like, and titin were found to be highly susceptible to oxidation under microwave irradiation. Notably, MW caused such modifications at cysteine site 9 in the head of myosin, revealing the enhancement mechanism of MP gelation by excess cysteine cross-linking during microwave processing. Furthermore, Gene Ontology and functional enrichment analyses suggested that the two thermal treatments resulted in some differences in ion binding, muscle cell development, and protein-containing complex assembly. Overall, this study is the first to report the redox proteomic changes caused by MW and WB treatments, thus providing a further understanding of the microwave-induced oxidative modifications of MPs.

With the aging problems increasing, the discovery of anti-aging compounds has become a popular research direction. Accumulation of free radicals and the consequent oxidative stress are the chief culprit of aging. Given this, cultured crocodile meat peptides-Maillard reaction product (CMP-MRP) with remarkable antioxidant activity was obtained via Maillard reaction of cultured crocodile meat hydrolysates and xylose. The antioxidant activity in vitro and anti-aging activity in vivo of CMP-MRP were investigated. Results indicated that the lifespan and the athletic ability of Drosophila were significantly improved after the administration of CMP-MRP in natural aging, H2O2- and paraquat-induced models. Furthermore, the antioxidant enzyme activities of Drosophila treated with CMP-MRP were enhanced while the levels of malondialdehyde (MDA) and protein carbonyl (PCO) were reduced in three Drosophila models. With the supplement of 5 mg/mL CMP-MRP in natural aging Drosophila model, the maximum lifespan increased from 61 days to 73 days, athletic ability raised by 95.45%, MDA and PCO reduced by 52.72% and 47.43%, respectively. Taken together, CMP-MRP exhibited outstanding antioxidant and anti-aging capacities in Drosophila models, suggesting that CMP-MRP possesses great potential in the health food and biomedicine fields as a food-derived anti-aging agent.

This work was aimed to compare the effect of microwave (MW) heating on the cathepsin L (Cat L)-induced degradation of myofibrillar protein (MP) gels with that of water bath (WB) heating. First, Cat L from silver carp was purified and determined to be 45 kDa. The gel strength of the MW-heated MP gels were significantly higher than those of the WB-heated when Cat L was added (P 0.05). The gel electrophoresis pattern and scanning electron microscopy analysis indicated that MW heating inhibited the Cat l-induced hydrolysis of MP gels. In addition, the number of sulfhydryl groups and surface hydrophobicity of MW-heated gels were lower than those of WB-heated gels when Cat L was added. These results indicated that MW heating could effectively weaken the degradation of Cat L on MP gels by manipulating disulfide bonds and hydrophobic amino acids, resulting in good gel properties and a compact protein network.

To reveal the application potential of microwave heating in the thermal processing of crayfish, this work explored the electromagnetic properties of different parts of crayfish and the patterns of temperature and moisture responses in crayfish during microwave heating. The results of electromagnetic analysis demonstrated that the electromagnetic properties of different parts of crayfish were different, and the tail had higher dielectric properties and reflective loss than other parts, but the maximum thickness of each part of crayfish was almost within their heating depth of microwave. The visual imaging and numerical simulation of temperature and moisture responses showed there were nonuniform temperature and moisture distributions in crayfish during microwave heating. The crayfish tail was selectively heated and rapidly cooked, but its moisture loss was far less than the mass loss of whole crayfish. Furthermore, the immobilized water in crayfish tail meat was continuously converted to free water, while the bound water was relatively stable during microwave heating. This work provided the theoretical references for the assumption that cooking the crayfish by microwave to overcome the shortcomings of boiling. PRACTICAL APPLICATION: In this work, we innovatively applied microwave heating to the heat processing of crayfish, and analyzed the electromagnetic properties of different parts in crayfish and explored its temperature and moisture responses under microwave field. Although this is a basic research, which provided some theoretical references for the assumption that microwave heating of crayfish (Procambarus clarkia) may be a clean and efficient means of overcoming the shortcomings associated with boiling. In particular, the simulation model of crayfish was established according to its real size and shape, which provided an option for the prediction of temperature response of crayfish in the microwave field.

Freezing technology is important for storage of animal products such as surimi. However, mechanical damage caused by ice crystals would lead to quality deterioration. This study aims to investigate the protective effect of antifreeze peptides (AFPs) on the quality of surimi during freezing storage and its possible mechanism. We found that AFPs exhibited a strong inhibition of ice crystal recrystallization, and the molecular weight ranged from 180 to 3000 Da. AFPs can prevent the degeneration of myofibrillar protein by reducing the loss of Ca2+-ATPase activity, slowing oxidation of sulfhydryl groups to disulfide bonds, and maintaining surface hydrophobicity and solubility of myofibrillar protein. Moreover, AFPs can reduce the influence of freezing stress on water mobility, thereby protecting the surimi from losing immobilized water and bound water during frozen storage. These findings indicate that AFPs could potentially serve as a food ingredient with antifreeze functional for the storage of surimi products.

Chopping and stirring methods were used to prepare surimi gels in a way that preserved their inherent characteristics while maintaining or improving their textural properties and microstructures. In samples with the same-salt levels, the stirring process led to a higher gel strength than the chopping process (P

Past studies have reported that microwave heating (MW) usually leads to higher cooking loss and texture deterioration in surimi processing. The objective of this study was to evaluate the effects of different microwave heating methods on surimi gel properties. Compared to traditional two steps water bath heating method (WB), using microwave heating to replace the first step of water bath heating would lead to the deterioration of surimi quality. By contrast, using microwave heating to replace the second step of water bath heating could significantly improve gel strength and water holding capacity. Microwave heating contributed to gelation and promoted the cross-linking of proteins via disulfide and non-disulfide covalent bonds. From scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM), microwave heating coupled to the traditional water heating method resulted in more compact network structures. Although the favorable gel strength was obtained by both the time-dependent mode and temperature preservation mode, CLSM three-dimensional micrographs revealed that the time-dependent mode contributed to shrinkage and rough surfaces. Therefore, the rapid heating rate of microwave results in the aggregation of proteins with superior texture, and the temperature-preservation mode results in desirable morphology and improved texture.

Moisture content plays an important role in aspects of the food processing such as energy transfer, food yield, and quality. This study investigated the effects of the moisture content of surimi on its electromagnetic characteristics. At moisture contents between 78% and 80%, both the dielectric constant and the dielectric loss increased, but gradually decreased with the increase of frequency. The strongest microwave absorption appeared at a thickness of 8 mm at 2.45 GHz. A moisture content of 0.45% was supplied to surimi using steam as an auxiliary heating method. The gel strength was obviously improved by a combination of microwave treatment (35 kW) and steam heating, and scanning electron microscopy showed that the network structure was also denser. In addition, the new heating mode with medium microwave power received the highest score on the comprehensive sensory evaluation after frying. The combination of microwave and steam preparation can save 11.68% ± 1.8% of the energy used in the conventional heating method, even when taking into account the combustion of methane produced during the wastewater treatment process.

In this study, a systematic analysis of the electromagnetic-thermal coupling effect of surimi was performed to develop a novel continuous processing method. A numerical model was established to analyze the heating effect and to predict the gel properties, and the accuracy of the model was verified under different flow rates. The results indicated that the combination of power inputs significantly affected the heating performance of surimi. Moreover, the coefficient of variation of the temperature profile at the outlet first increased and then decreased with the increase in the power input from E-plane (PE). However, a higher PE led to worse temperature control of the surimi near the ports, which was mainly affected by the power density and should be considered because of the high risk of tube fouling. In addition, the effect of the microwave-assisted pre-gel effect can be further improved by adjusting the flow rate of the surimi according to the thermal efficiency.

Lactic acid bacteria as starter cultures can lead to rapid acidification for gel formation in fermented fish sausages. However, there is lack of study on the volatile flavor characteristics after starter culture addition and how they affect the microbial community on the flavor formation in fish sausages. In this work, the changes of volatile compounds and microbial community in the tilapia sausage during fermentation with Pediococcus pentosaceus were respectively studied by the headspace solid-phase microextraction gas chromatography-mass spectrometry and 16S rRNA gene high-throughput sequencing. A total of 83 volatile compounds were identified, among which 32 compounds were selected as the core volatile flavor compounds. The microbial diversity in the sausage significantly decreased as the fermentation time increased. There were 12 main microbial genera in whole fermentation stages. The anaerobes such as Pediococcus, Lactococcus, Enterobacter, and Citrobacter increased obviously after fermentation, especially for Pediococcus and Lactococcus, whose total abundance reached over 95% at the end of fermentation. The correlation network model showed that Pediococcus and Lactococcus contributed most to the volatile flavor formation, followed by Enterobacter, Citrobacter, and Photobacterium. This research provides an effective method to accelerate the volatile flavor formation and inhibit the spoilage microorganisms in the fermented tilapia sausage.

This study investigated the effects of fish mince size on the gelling properties of silver carp surimi gel produced by microwave heating combined with the water bath method. As the mince size increased, the mince protein and fat contents increased, but the moisture content decreased. Although the strength and water holding capacity of the surimi gel obtained from the larger mince were lower, the detrimental effect resulting from this larger size was considerably reduced by microwave heating; this afforded the fast and selective heating of the heterogeneous surimi. A soft textured compact gel structure was obtained from the 4 mm fish mince based on the results of the texture profile analysis and scanning electron microscopy. These results are anticipated to aid in the formulation of a method for reducing the loss in the processing of muscle fibers to realize the accurate and moderate processing of low-value fish.

The aim of this study was to compare the physicochemical properties of chitosan prepared by microwave and water bath heating with an equivalent quantity of heat intake. The structure and physicochemical properties of the chitosan obtained by these two methods were characterized by Fourier transform infrared spectroscopy (FTIR), X‐ray diffractometry (XRD), gel permeation chromatography (GPC), and scanning electron microscopy (SEM). The FTIR and XRD patterns show that there was no significant difference in the structure of chitosan produced by the two heat sources. The results showed that chitosan with 73.86% deacetylation was successfully prepared by microwave heating within 60 min, while a longer time of 180 min was required for the preparation of chitosan with the same deacetylation degree (74.47%) using the conventional heating method under the same heating rate. Even under the same temperature conditions, microwave technology can greatly reduce the reaction time by approximately 1/3, while the chitosan produced by microwaves can obtain relatively low molecular weight and viscosity. These results showed that microwaves may efficiently promote complete chemical reactions by the friction heating mechanism generated by molecular vibration beyond a rapid heating source, turning into a more efficient, energy‐saving, and environmentally friendly method for the further use of rigid shrimp shells and highly crystalline crustacean materials., The physicochemical properties of chitosan prepared by microwave and water bath heating were compared with an equivalent quantity of heat intake. There was no significant difference in the structure of chitosan produced by the two heat sources. Microwave technology can greatly reduce the reaction time by approximately 1/3, while the chitosan produced by microwaves can obtain relatively low molecular weight and viscosity.

To improve the gelation performance of konjac glucomannan (KGM) thermo-irreversible gel in the condition of alkaline, this study investigated the interactions between KGM and curdlan (CUD) in terms of the sol state and gelation process. The apparent viscosity, rheological properties during heating and cooling, thermodynamic properties, gelation properties and water holding capacity of KGM/CUD blend systems in an alkaline environment were studied using physical property testing instruments and methods. The results showed that the viscosity of the KGM/CUD blended solution was greater than the value calculated from the ideal mixing rules in the condition of alkaline (pH = 10.58). As the proportion of CUD in the system increased, the intersection of storage modulus (G&rsquo, ) and loss modulus (G&rdquo, ) shifted to low frequencies, the relaxation time gradually increased, and the degree of entanglement of molecular chains between these two components gradually increased. The addition of CUD helped decrease the gelation temperature of KGM, increased the gelation rate and inhibited the thinning phenomenon of KGM gels at low temperatures (2&ndash, 20 &deg, C). The addition of CUD increased the hardness and gel strength of KGM but did not significantly improve the water holding capacity of the KGM/CUD blend gel. The process of mixing KGM and CUD improved the thermal stability of the gel. In summary, KGM/CUD exhibited excellent compatibility under alkaline conditions, and the blend systems produced a &ldquo, viscosifying effect&rdquo, KC8 and KC5 show better thermal stability, low temperature resistance and gel strength compared to KGM. This blended gel can be used as a structural support material to provide reference for the development of konjac bionic vegetarian products.

Dried minced pork slices (DMPS) have been widely accepted owing to their unique flavor and taste, but traditional roasting (TR) process for making DMPS are time-consuming and complicated. This study presents a microwave heating (MH) method for rapid preparation of DMPS with different fat pork levels. The results indicated that DMPS size significantly affected the MH patterns. As the fat pork content increased, the complex permittivity showed a downward tendency, and the 30% fat pork content improved both the heating rate and uniformity. Fat components significantly altered the texture and color characteristics, but DMPS made by MH possessed a higher hardness and toughness values than TR. Low-field nuclear magnetic resonance analysis demonstrated that the proportion of T21 gradually decreased in MH group, while no distinct changes were observed in the TR group with the increase of fat pork content. In addition, the results of comprehensive sensory evaluation in the MH and TR groups revealed that such a convenient MH technology is alternative for the fabrication of DMPS with acceptable product quality.