Application effects of NaCl substitute on the fermentation profile of Pixian douban (broad bean paste).

The effects of a reduced-salt substitute (composed of NaCl, sodium gluconate, KCl, L-histidine, and L-lysine) applied in the fermentation of traditional Pixian douban (PXDB) were explored in this study according to sensory quality, physicochemical characteristics, color, colony count, and the contents of free amino acids (FAAs), organic acids, and volatile flavor compounds. The results showed that the PXDB with a 15% salt substitution had the most attractive reddish-brown color, a mellow fragrance, and the lowest total colony count of the three pastes. The fermentation quality of the 15% salt substitute PXDB was superior to that of the control groups, its sensory quality was more readily accepted, and the contents of its amino acid nitrogen, FAAs and organic acids had increased by 0.1050, 0.3290, and 3.9068 mg/g, respectively. Moreover, the concentrations of the main aroma compounds in the PXDB containing the salt substitute were higher than those of the control. These included phenylethanol, 3-methylthiopropanol, isoamyl alcohol, furfural, benzaldehyde, phenylacetaldehyde, nonanal, isoamyl aldehyde, 4-ethylphenol, and, particularly, 2,6-dimethylpyrazine, which had increased as much as 100 times. Correlation analysis showed that Glu, Phe, Tyr, Gly, Leu, Val, Asp, Ile, citric acids, and succinic acids were all positively correlated with the main aroma and contributed to the generation of PXDB's characteristic flavor, and main aroma substances in turn positively influence PXDB flavor sensory attributes. Overall, these results showed the application of the 15% salt substitute during PXDB fermentation improved the quality of the paste and, thus, would benefit the development of reduced-salt PXDB.

Effect of dense phase carbon dioxide treatment on the flavor, texture, and quality changes in new-paocai.

This study investigated the effect of dense phase carbon dioxide (DPCD) treatment on the organoleptic properties of new-paocai. Optimal DPCD treatment (25 MPa/40 °C/40 min) was determined by conducting single-factor and orthogonal experiments with the sensory, bactericidal, and electronic eye evaluations. DPCD treatment (25 MPa/40 °C/40 min) did not significantly affect the nitrite, pH, total acid, and organic acid of the new-paocai brine, and the texture of the radish slices did not display substantial changes. Gas chromatography-mass spectrometry (GC-MS) was employed to characterize the new-paocai brine flavor, revealing 63 and 60 respective flavor compounds with and without DPCD treatment. In addition, DPCD treatment significantly reduced the total organic volatile compound content in the paocai from 48.182 µg/mL to 35.952 µg/mL, DPCD has a great influence on volatile flavor substances. The electronic nose (E-nose) effectively distinguished the flavor differences in the new-paocai brine with and without DPCD treatment. This study combined new food processing technology with traditional food production, could provide a new idea for pickle production technology.

HS-SPME-GC × GC/MS combined with multivariate statistics analysis to investigate the flavor formation mechanism of tank-fermented broad bean paste.

With the advancement of industrialization, tank fermentation technology is promising for Pixian broad bean paste. This study identified and analyzed the general physicochemical factors and volatile metabolites of fermented broad beans in a thermostatic fermenter. Headspace solid-phase microextraction (HS-SPME)-two-dimensional gas chromatography-mass spectrometry (GC × GC-MS) was applied to detect the volatile compounds in fermented broad beans, while metabolomics was used to explore their physicochemical characteristics and analyze the possible metabolic mechanism. A total of 184 different metabolites were detected, including 36 alcohols, 29 aldehydes, 26 esters, 21 ketones, 14 acids, 14 aromatic compounds, ten heterocycles, nine phenols, nine organonitrogen compounds, seven hydrocarbons, two ethers, and seven other types, which were annotated to various branch metabolic pathways of carbohydrate and amino acid metabolism. This study provides references for subsequent functional microorganism mining to improve the quality of the tank-fermented broad beans and upgrade the Pixian broad bean paste industry.

Effects of different antioxidants combined with high hydrostatic pressure on the color and anthocyanin retention of a blueberry juice blend during storage.

Blueberry juice has been found to undergo severe browning after treatment and cold storage, such as processing by high hydrostatic pressure (HHP) at 550 MPa/10 min/25 °C followed storage at 4 °C for 4 days. This browning may be due to the degradation of anthocyanin (AC) in the berries. Therefore, in this study, gallic acid (GA), ferulic acid (FA), ascorbic acid (VC), citric acid (CA), tea polyphenol (TP) and α-tocopherol (VE) were compared to determine their ability to improve the stability of the AC in HHP-treated blueberry juice. The juice was combined with the six abovementioned antioxidants at different concentrations, then treated by HHP at 550 MPa/10 min/25 °C and stored at 4 °C for 20 days. Thereafter, the pH levels, degrees °Brix, color parameters, total AC content and polyphenol oxidase (PPO) activity of the blueberry juice blend were measured and compared. Gallic acid at 2 g/L was found to be the most effective antioxidant to protect against AC degradation. After storage at 4 °C for 20 days, the AC content of the juice with no added antioxidants had decreased by 62.27% with a PPO relative activity of 50.78%, while the AC content of juice supplemented with 2 g/L GA had decreased by 13.42% with a PPO relative activity of 28.13%. The results of this study, thus, suggest that GA can stabilize the structure of AC in blueberry juice and reduce PPO activity, which may be beneficial in guiding the production of blueberry juice with high AC retention.

Complex coacervation of soy protein isolate-limited enzymatic hydrolysates and sodium alginate: Formation mechanism and its application.

The complex coacervation of soybean protein isolate and polysaccharide has been widely applied for preparing biopolymer materials like microcapsule. In this study, hydrolytic soy protein isolate (HSPI) was prepared by mild hydrolysis of soy protein isolate (SPI) with fungal protease 400 (F400). The degree of hydrolysis (DH) for the enzymatic products was controlled at 1%-5%. Emulsification, oxidation resistance, and thermal stability were used to evaluate the performances of HSPI with different DH. The results showed that the HSPI with the hydrolysis degree of 2% had the optimal property. Subsequently, the complex polymer of HSPI/SA was prepared by the coalescence reaction of HSPI and sodium alginate (SA). The turbidity curves manifested the optimal complex coacervation occurred at the ratio of 7:1 (HSPI:SA). Fourier transform infrared spectroscopy (FTIR) presented that the reaction involved electrostatic interactions between -NH3 + in HSPI and -COO- in SA. Isothermal titration calorimetry experiments indicated that the complex coacervation reactions of HSPI and SA arose spontaneously. The microencapsulation by complex coacervation of HSPI and SA was further produced for embedding sweet orange oil. The thermogravimetric analysis (TGA) result revealed that the microencapsulation system of HSPI/SA had a better heat resistance than that using the SPI/SA complex polymer.

Insight into the protein degradation during the broad bean fermentation process.

Broad bean fermentation is of vital importance in PixianDouban (PXDB) production, as well as a key process for microorganisms to degrade protein, which lays the foundation for the formation of PXDB flavor. In this study, two fungi and bacteria were screened, and their morphology, molecular biology, growth, and enzyme production characteristics were analyzed, and then they were applied to the broad bean fermentation simulation system. The protein, peptide, amino acid, amino nitrogen, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) in the system were evaluated. The results showed that the four microorganisms were Aspergillus oryzae, Aspergillus jensenii, Staphylococcus gallinarum, and Enterobacter hormaeche. Aspergillus oryzae had the highest protease activity at pH 7.0, while the other three strains had better enzyme activity stability under neutral acidic conditions. And the total protein (F1 and F2 were 18.32 g/100 g, 19.15 g/100 g, respectively), peptides (11.79 ± 0.04 mg/g and 12.06 ± 0.04 mg/g), and amino acids (55.12 ± 2.78 mg/g and 54.11 ± 1.97 mg/g) of the fungus experimental groups (F) were higher than the bacterial experimental groups (B). In addition, the enzyme system produced by fungi exhibited a stronger ability for albumin (20 kDa) and glutenin (<30 kDa) deterioration in neutral conditions, while the bacterial enzyme system was more efficient in degrading albumin (<30 kDa) and glutenin (20-30 kDa) in acidic conditions, as indicated by SDS-PAGE. These findings showed that both bacteria and fungi played an important role in the degradation of protein in different fermentation stages of broad bean fermentation. Practical applications: There is a lack of comprehensive understanding of the protein composition and protein degradation mechanism of broad beans in the fermentation stage of PXDB. This research work explored the differences in the degradation of PXDB fermented protein by different microorganisms, and provided a theoretical basis for optimizing the production of PXDB and improving the quality of PXDB.

Isolation, identification and characterization of taste peptides from fermented broad bean paste.

Pixian broad-bean paste (PBBP) is a famous fermented condiment in China, which may produce abundant flavor peptides during the fermentation process. Herein, the flavor peptides from fermented broad-bean (FB) were separated and identified via ethanol precipitation, macroporous resin, and ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS/MS) methods. The results showed that there were fifteen novel flavor peptides in FB. Among them, six peptides (i.e. ALDELGT, AELTPEP, SAALQAG, SFEAVEAAPT, EQDNDGNNIFSGFKR, QTFNTEEDTAK, and DAPASGN) were perceived umami with threshold values ranging from 0.76 to 1.84 mmol L-1. And they had both salty-enhancing and umami-enhancing abilities. Meanwhile, novel peptides (i.e. GGLRIINPEGQQ, SIITPPERQ, GGLSIITPPERQA, GGLRIINPEG, SIITPPER, RIINPEGQQ, DALNVNRHIV, and LPKILLLQLV) were perceived bitter with threshold values ranging from 0.56 to 2.89 mmol L-1. And the monosodium glutamate (MSG) solution had a certain masking effect on bitter peptides. GFSSEFLA showed a strong sweet taste. From peptide sequence analysis, it was found that Aspergillus oryzae and broad-bean were important taste-active sources of the flavor peptides in FB. Besides, the synthetic peptides showed a much better sensory taste than the mixtures of the corresponding amino acids. It indicated that peptides might play an important role in deciding the taste of FB. Significantly, it is the first time that the isolated flavor peptides were identified from FB.

Determination of aflatoxin B1 in Pixian Douban based on aptamer magnetic solid-phase extraction.

Aflatoxin B1 (AFB1) is considered as the most prevalent and toxic mycotoxin in food, and is the indispensable index in the monitoring of Pixian Douban, a traditional chinese fermented bean paste from Sichuan. However, the effeciency of AFB1 detection in Pixian Douban is influenced by the traditional extraction, which is usually complex and time consuming. Therefore, an aptamer-based magnetic solid-phase extraction method was designed for the pretreatment of AFB1 in this sample, for which Fe3O4 was synthesized via the solvothermal method and then a Fe3O4@SiO2-NH2 with a core-shell structure was prepared, followed by an AFB1-aptamer attachment. The validation was performed via an enzyme-linked immunosorbent assay and compared with HPLC-MS/MS. The linearity range of this method was 0.5-2.0 ng mL -1 with R 2 of 0.981, and recoveries of AFB1 ranged from 80.19% to 113.92% with RSDs below 7.28% with no significant differences compared to HPLC-MS/MS. The three-time reusability efficiencies of aptamer-MNPs were averaged at 78.24%. The results proved that aptamer-MNPs were high-performance adsorbents for extracting and enriching AFB1, facilitating quick and effective detection of AFB1 in Pixian DouBan samples.

Fermentation characteristics of Pixian broad bean paste in closed system of gradient steady-state temperature field.

A closed system of gradient steady-state temperature field (GSTF) was constructed to ferment Pixian broad bean paste (PBP). The contents of physicochemical factors and organic acids in the fermentation under GSTF (FG) were closer to those in the traditional fermentation (TF). The taste intensities of 8 free amino acids in the FG were higher than those in the constant temperature fermentation (CTF), but 14 in the TF showed the highest among the processes of FG, CTF and TF. The FG product had the most volatiles with 87, and its flavor properties were more stable. The FG produced great effects on the microbe evolutions especially improved the fungal diversity. Bacillus were identified as the core microbes in the FG while the roles of Staphylococcus, Lactobacillus and Pantoea were strengthened. The results indicated that the fermentation characteristics in the FG had been further improved compared with the CTF.

Sensory and Volatile Compounds Characteristics of the Sauce in Bean Paste Fish Treated with Ultra-High-Pressure and Representative Thermal Sterilization.

This study investigated the differences between three sterilized samples to reveal the unique aroma characteristics of the sauce in bean paste fish by multiple analysis methodologies. Samples were subjected to pasteurized (PS), high-temperature sterilization (HTS), and ultra-high-pressure treatment (UHP) tests. The UHP had a higher sensory evaluation and could better maintain the original flavor of the sample. A total of 92, 83, 85, and 76 volatile compounds were detected via comprehensive two-dimensional gas chromatography-mass spectrometry (GC×GC-MS) techniques in the control (CT), PS, HTS, and UHP groups, respectively. According to the analysis of gas chromatograph-olfactometry and odor activity value, 7 compounds were considered to have an aromatic influence on the sauces, in which four compounds (1,8-Cineole, Linalool, Hexanal, and Dimethyl trisulfide) exhibited a positive contribution to the aroma of the sauces. PLS-DA results showed that the UHP group positively correlated with volatiles (Isoamylol and 1-Octen-3-ol), color, and gloss. In general, the UHP treatment could retain the original state and flavor of the sauce, showing a high similarity to the control group. The HTS significantly altered the flavor and status of the samples.

Characterization of volatile compounds of Pixian Douban fermented in closed system of gradient steady-state temperature field.

As an essential flavor condiment in Sichuan cuisine, Pixian Douban (PXDB) is usually produced by open fermentation process in strip pools or ceramic vats. In this study, an experiment of PXDB fermentation was conducted for 90 days in a closed system of gradient steady-state temperature field (GSTF). To investigate the characterization of volatile compounds of PXDB in the closed system, the volatiles in three kinds of samples including samples of GSTF (SGT), samples of constant temperature (SCT), and samples of traditional fermentation (STF) were analyzed. The results showed that 75, 67, and 68 volatile compounds were detected in SGT, SCT, and STF, respectively. Compared with the traditional fermentation, the process in the closed system of GSTF was conducive to produce more kinds of esters and alcohols. A total of 22 major aroma active compounds were identified in three samples by combination analyses of gas chromatography-olfactometry (GC-O) and odor activity value (OAV). The appearance, smell, texture, and taste of the three different samples had shown different changes, but the sensory characteristics of the SGT were more similar to those of the STF by quantitative descriptive analysis (QDA) and principal component analysis (PCA). This study indicated that the closed system of GSTF could be applied in PXDB fermentation to obtain higher quality products, which brought a bright prospect of replacing the traditional fermentation process to realize the controllable industrialized production of PXDB.

Simultaneous determination of eight biogenic amines in the traditional Chinese condiment Pixian Douban using UHPLC-MS/MS.

A UHPLC-MS/MS method was developed to simultaneously determine eight biogenic amines (BAs) in Pixian Douban. Under optimal conditions, the linear ranges of determination were 5-1000 µg/L (that of spermine was 8-1000 µg/L). Correlation coefficients ranged from 0.9955 to 0.9987. The limits of detection were 0.11-5.5 µg/L. The matrix effect and analytical performance of the present method were evaluated, and the eight BAs were analyzed by this method in 19 samples, indicating the potential pollution of BAs in chili oil Pixian Douban.

Discrimination of Zanthoxylum bungeanum Maxim through volatile aroma compounds analysis with artificial neural network.

Zanthoxylum bungeanum Maxim (ZBM), a special spice from Chinese different areas, have a widespread variation in quality and price. To avoid the commercial adulteration of ZBM, it is necessary to discriminate them from different areas. As volatile aroma compounds (VAC) have the potential to discriminate ZBM, electronic nose (E-nose) was used to preliminarily discriminate the VAC through sensor response analysis, radar chart analysis, and principal component analysis. Then, Gas chromatography-mass spectrometry (GC-MS) was utilized to identify VAC through hierarchical cluster analysis and quantitative analysis. Finally, artificial neural network (ANN) was employed to assess the accuracy of the discrimination of ZBM. As a result, we found that ZBM could be successfully discriminated between Chinese Sichuan and the other areas. Our findings would provide guidance for evaluating and predicting the variation of VAC of ZBM from different areas in further study. PRACTICAL APPLICATIONS: Zanthoxylum bungeanum Maxim (ZBM) is a traditional and important spice used in Sichuan cuisine especially hotpot, which are famous all over overseas. However, the ZBM from different producing areas bring various flavors, hampering the quality of Sichuan cuisine developing toward to standardization. Therefore, the authors in this work pursuit an effective way to distinguish the ZBM produced in Sichuan rather than in other province. According to the results of the present study, ZBM could be successfully discriminated between Chinese Sichuan and the other producing areas by using E-nose and GC-MS through artificial neural network. These findings would provide the guidance for evaluating the producing areas of ZBM to be whether or not Sichuan, which could offer the practical help in the purchase of the raw material in the supply chain. Besides, these also can be applied to predict the variation of volatile aroma compounds of the ZBM in the further study.

Effect of different superfine grinding technologies on the physicochemical and antioxidant properties of tartary buckwheat bran powder.

The effect of shear crushing, airflow comminution, and wet grinding on the physical and chemical properties of Tartary buckwheat bran (TBB) powder was compared. Superfine grinding significantly reduces the particle size of bran (1.644 µm), while increasing the protein content (23.60%), water-holding capacity (4.38 g g-1), solubility (21.077 g 100 g-1), bulk density (0.34 g mL-1), and tap density (0.53 g mL-1) providing good processing characteristics. The antioxidant properties of bran powder prepared by the three methods mentioned above were compared. The results showed that different bran powders subjected to superfine grinding displayed varying levels of antioxidant capacity. The quercetin content (2.18 g 100 g-1) of the wet-grinding bran powder (WGBP) was twice that of the control group, while no rutin was detected. The total flavonoid content (TFC) and total phenolic content (TPC) were significantly different from those of other groups. The DPPH, ˙OH, and ABTS+ removal rates were 60.74%, 86.62%, and 92.98%, respectively, while that of ˙OH was significantly higher than in the other treatment groups. The control group, shear crushed, and airflow comminution bran exhibited no significant differences in TFC, TPC, and oxidation resistance, except for the ability to remove ˙OH. TBB powder obtained via superfine grinding displayed superior taste and functional characteristics, providing a theoretical reference for the processing of this bran.

Dynamics and correlation of microbial community and flavor in Pixian Douban fermented with closed process of constant temperature.

BACKGROUND: As a Chinese traditional flavor condiment, Pixian Douban (PXDB) is produced using a traditional open fermentation process. In this study, an experimental fermentation of PXDB was conducted at 40 °C for 90 days in a closed system, which has not been applied to PXDB production. The flavor, microbial community and correlations of the samples in the closed system were compared with those in the traditional fermentation. RESULTS: The content of organic acids and free amino acids in the closed fermentation of constant temperature (CFCT) achieved the standards of product quality, although they were lower than those in the traditional fermentation. Of the 140 detected aroma components, 98 were shared in the two fermentation processes. Enterobacter, Bacteroides and Megamonas were the core microbial genera related to 26 flavor components in the traditional fermentation, while Pantoea was the core microbial genus related to 18 flavor components in CFCT. The CFCT has its own unique advantages over traditional fermentation in forming aromas. It produced a greater impact on the succession of fungi than those of bacteria after changing traditional fermentation to CFCT. The influence of microorganisms on the formation of flavor components was relatively more balanced in CFCT, while the changed fermentation process impacted greatly on the functions of Zygosaccharomomyces and Pichia but little on those of Sphingomonas, Megamonas and Parabacteroides. CONCLUSION: The study indicated that it was feasible to ferment PXDB in the closed system, and provides a basis to realize controllable PXDB production. © 2020 Society of Chemical Industry.

Effects of different ozone treatments on the storage quality and stability of fresh peeled garlic.

In order to understand their impacts on the preservation of fresh garlic, varying concentrations of ozone gas and different storage temperatures were tested for this experiment. The results demonstrated that freshly peeled garlic was best preserved by an ozone concentration of 5 ppm and storage at 4 °C compared to other treatment groups. With these optimized conditions, after 25 days of storage, the weight of garlic decreased by only 1.89% and, under the same storage conditions, the water loss rate was only 65.17% that of the control group, with a decay rate of only 12.50%. The rate of decay in the blank control group was three times that of this group. The germination rate was also low: only 30.26%, which was 57.69% that of the blank control group. The hardness was measured at 7.48 kg cm-2, 19.79% higher than that of the blank group. The content of soluble solids was 9.15 g 100 mL-1, which was 10.27% higher than that of the blank group, again proving that the above storage parameters were effective. At the same time, the titratable acid (TA) in the garlic was 15.48%, which was 1.17 times that of the blank group and corresponds to the vitamin C content. Also, the content of diallyl trisulfide only decreased by 3.98% and was 11.2% higher (P < 0.01) than that of the blank group. Finally, the validity of this optimal result was also confirmed by sensory evaluation. These results, for garlic, support the application of ozone as a safe, non-thermal preservation technique benefiting both producers and consumers.

Correlation between microbial communities and key flavors during post-fermentation of Pixian broad bean paste.

Pixian broad bean paste (PBP) is a traditional Chinese condiment, famous for its distinctive flavor. Microbial communities play a vital role in producing the unique flavor of PBP, and a significant accumulation of these volatile flavors occurs during the post-fermentation stage of its production. However, little is known about the relationship between the microbes and flavor compounds in PBP. In this study, high-throughput sequencing (HTS) analysis revealed that Leuconostoc (8.30%), Lactobacillus (7.05%), Weissella (5.80%) and Staphylococcus (4.03%) were the dominant bacterial genera, while the most prevalent yeast genera were Zygosaccharomyces (41.45%) and Pichia (5.83%). Gradual accumulations of free amino acids (glutamic acid and asparagine), organic acids (malic acid and tartaric acid), and unique volatiles (aldehydes, phenols and pyrazines) were evident throughout the post-fermentation process. Analysis of the Pearson's correlation coefficients between 66 key microbes and the key flavors was investigated. Nine core microbes were identified based on the linear discriminant analysis (LDA) scores ≥ 4 (or an average abundance >0.1%) and a high correlation with at least two flavor categories (P < 0.05, |ρ| > 0.8), namely Kosakonia, Kazachstania, Debaryomyces, Lactobacillus, Myroides, Stenotrophomonas, Ochrobactrum, Wohlfahrtiimonas, and Lactococcus genera. These results provide a clearer insight into microbial succession during PBP post-fermentation, thereby contributing to further quality improvement of PBP.

The effect of high-power ultrasound on the rheological properties of strawberry pulp.

This study investigated the effects of high-power ultrasound (HPU, 0-45 °C, 242-968 W/cm2, 2-16 min) on the rheological properties of strawberry pulp. Following the HPU treatment, the strawberry pulp exhibited an increase in apparent viscosity, storage modulus (G'), and loss modulus (G″). The water-soluble pectin (WSP), pectin methylesterase (PME) activity, and free calcium ions (Ca2+) of the strawberry pulp after HPU treatment were investigated to determine a possible reason for this phenomenon. HPU caused a significant decrease in the degree of esterification (DE), molecular weight (Mw), and particle size of strawberry WSP, but no significant changes were evident in the galacturonic acid (GalA) content and the zeta (ζ)-potential (P > 0.05), resulting in decrease in the apparent viscosity. Moreover, the largest reduction of PME activity was 22.6% after HPU treatment at 605 W/cm2 and 45 °C for 16 min, indicating that the PME was resistant to the HPU treatments. The free Ca2+ content in the strawberry pulp was significantly decreased after exposure to HPU (P < 0.05). The maximal reduction of 52.01% in the free Ca2+ was achieved at 605 W/cm2 and 45 °C for 16 min. The overall results indicated that the high residual activity (RA) of PME after HPU might induce the low esterification of WSP, while HPU promoted the interaction of free Ca2+ and low-methylated pectin, to form the network structure of Ca2+-low-methylated pectin, resulting in an increase in viscosity in the complex strawberry system.

Effects of high pressure processing (HPP) on microorganisms and the quality of mango smoothies during storage.

The objective of this study is to investigate the effects of high pressure processing (HPP) on the quality of mango smoothies and the inactivation of microorganisms therein, with heat treatments used as the control. Comparative analysis was conducted on the microbiological changes in the mango smoothies subjected to HPP at 400-600 MPa for 0-15 min. The total plate count (TPC) and the yeast and mold (YM) counts were found to be significantly inactivated through increases in the pressure and treatment time (p < 0.05). Conditions of 90 °C/20 min (HT), 500 MPa/8 min (HPP-500) and 600 MPa/5 min (HPP-600) were, thus, selected as the subsequent treatment for a storage study at 4 °C for 15 days, since these conditions had similar inactivation effects on TPC and YM. After 15 days of storage, the TPC was found to have increased by 3.87, 3.54 and 3.36 log10 cycles in the mango smoothies treated by HT, HPP-500 and HPP-600, respectively, while the YM counts remained at less than 1 log10 cycle in all samples. During storage, compared to the HT and HPP-600 samples, both the color and viscosity at 100 s-1 of samples treated by HPP-500 were found to be better maintained. Carotene content was better retained in storage after the HPP process than after the HT process. However, the different treatments had no effect on the pH nor on the total soluble solids (TSS) in the samples. The study ascertained that HPP-500 is able to ensure both the microbial safety and the quality of mango smoothies more effectively than HT and HPP-600.

Effects of combination treatments of lysozyme and high power ultrasound on the Salmonella typhimurium inactivation and quality of liquid whole egg.

An investigation was conducted into the utilization of treatments combining ultrasound and lysozyme (US + Lys) to deactivate Salmonella typhimurium (S. typhimurium) in the liquid whole egg (LWE). Furthermore, US + Lys and heat treatment (HT) with a similar microbial inactivation effect were comparatively evaluated by examining their impact on the quality attributes of LWE. The LWE was treated with US at 35-45 °C and 605-968 W/cm2 for 5-35 min, and with HT at 58-64 °C for 3-4 min. Lysozyme (Lys) alone achieved a minimal degree of inactivation in S. typhimurium, while it was enhanced with the application of US alone when the treatment temperature, time, and energy were increased. Furthermore, US and US + Lys caused a reduction of 3.31 and 4.26 log10 cycles in S. typhimurium, respectively at 968 W/cm2 and 35 °C for 20 min, indicating a synergistic relationship between US and Lys for the effective inactivation of S. typhimurium. Similarly, HT and HT + Lys achieved a reduction of 4.10 and 4.75 log10 cycles at 64 °C/3 min, respectively. The L* and b* values of the LWE following US and US + Lys application were significantly higher than untreated and heat-treated LWE, indicating that US treated LWE had a brighter and yellower appearance. The protein solubility (PS) slightly decreased after all treatments, while the pH increased. Furthermore, the foaming capacity (FC) and foam stability (FS) were decreased, revealing that LWE had a lower FC and unstable foam after all treatments. Therefore, US and US + Lys could increase the viscosity and gelation temperature (Tg) of LWE, indicating that LWE exhibited higher heat resistance after US treatment. These results indicated that US + Lys might be a promising pasteurization technology in the processing of LWE.