Physicochemical, microbiological, and sensory properties of low-lactose yogurt using Streptococcus thermophilus with high ß-galactosidase activity.

BACKGROUND: Lactose maldigestion or intolerance affects a large number of individuals worldwide. If lactose is hydrolyzed by the ß-galactosidase enzyme during the fermentation process, lactose-intolerant individuals can consume milk products without experiencing diarrhea, flatulence, or other symptoms. RESULTS AND CONCLUSION: We isolated and characterized Streptococcus thermophilus, which exhibits high ß-galactosidase activity. This was then used as a starter culture with Lactobacillus delbrueckii subsp. bulgaricus in yogurt to determine the effects of different starter ratios and fermentation temperatures on its organoleptic and physical properties. The ß-galactosidase activity of the isolated strain was 2.60 units mg-1 . The optimal temperature was 42 °C for St. thermophilus to acidify yogurt faster than at other temperatures and it was effective in hydrolyzing the lactose in the media and yogurt. The lactic acid bacteria (LAB) population in 37 °C fermented yogurt was higher than in the other samples, but the starters St. thermophilus and Lb. bulgaricus with a ratio of 2:1 used lactose more effectively than other sample ratios. The lactose content decreased significantly at 37 °C, where it was ~50% hydrolyzed. The acceptability of the sensory properties of yogurt was unaffected by relative lower fermentation temperatures (30 and 37 °C), despite using different ratios of St. thermophilus and Lb. bulgaricus as starter cultures. © 2023 Society of Chemical Industry.

Corosolic acid ameliorates non-alcoholic steatohepatitis induced by high-fat diet and carbon tetrachloride by regulating TGF-ß1/Smad2, NF-κB, and AMPK signaling pathways.

Hawthorn (Crataegus pinnatifida Bunge. var. major) is an edible and medicinal fruit that is very common in food and traditional Chinese medicine. Corosolic acid (CA), a pentacyclic triterpenoid, which is an active component of hawthorn (Crataegus pinnatifida Bunge. var. major), has been exhibiting various pharmacological activities such as antidiabetic, antibacterial, anticancer, antiinflammatory, and antioxidant effects. The study aimed to evaluate the effect of CA on non-alcoholic steatohepatitis (NASH) in mice induced by 60 kcal% high-fat diet (HFD) and carbon tetrachloride (CCl4 ). CA lowered liver index and serum AST, ALT, TG, and TC levels compared to those in the model group. Histological analyses of the liver tissues of mice treated with CA revealed significantly decreased number of lipid droplets and alleviated inflammation and fibrosis. CA inhibited the transcripts of pro-fibrogenic markers (including α-SMA, collagen I, and TIMP-1) and the levels of pro-inflammatory cytokines (including TNF-α, IL-1ß, caspase-1, and IL-6) associated with hepatic fibrosis, and NF-κB translocation and TGF-ß1/Smad2 and AMPK pathways. In addition, CA reduced lipid accumulation via the regulation of AMPK and NF-κB activation in FFA-induced steatotic HepG2 cells. CA also decreased α-SMA, collagen I expressions, and Smad2 phosphorylation, which were reduced by TGF-ß1 treatment in LX2 cells. Our results suggested that CA ameliorated NASH through regulating TGF-ß1/Smad2, NF-κB, and AMPK signaling pathways, and CA could be developed as a potential health functional food or therapeutic agent for NASH patients.

Improving thermostability of (R)-selective amine transaminase from Aspergillus terreus through introduction of disulfide bonds.

To improve the thermostability of (R)-selective amine transaminase from Aspergillus terreus (AT-ATA), we used computer software Disulfide by Design and Modelling of Disulfide Bonds in Proteins to identify mutation sites where the disulfide bonds were most likely to form. We obtained three stabilized mutants (N25C-A28C, R131C-D134C, M150C-M280C) from seven candidates by site-directed mutagenesis. Compared to the wild type, the best two mutants N25C-A28C and M150C-M280C showed improved thermal stability with a 3.1- and 3.6-fold increase in half-life (t1/2 ) at 40 °C and a 4.6 and 5.1 °C increase in T5010 . In addition, the combination of mutant R131C-D134C and M150C-M280C displayed the largest shift in thermostability with a 4.6-fold increase in t1/2 at 40 °C and a 5.5 °C increase in T5010 . Molecular dynamics simulation indicated that mutations of N25C-A28C and M150C-M280C lowered the overall root mean square deviation for the overall residues at elevated temperature and consequently increased the protein rigidity. The stabilized mutation of R131C-D134C was in the region of high mobility and on the protein surface, and the disulfide bond constraints the flexibility of loop 121-136.

[Isolation, characterization and real-time RT-PCR for relative quantification of gene expression in H+-ATPase-defective mutants from Lactobacillus plantarum].

Objective: The aim of this study was to isolate Lactobacillus plantarum acid-sensitive mutants with lower H+-ATPase activity, and to study the mechanism of H+-ATPase regulation in Lactobacillus plantarum. Methods: We used neomycin to isolate acid-sensitive mutants of L. plantarum, and measured H+-ATPase activity and lactic acid production of wild-type and mutants. Genomic DNA was extracted from the wild-type ZUST and two mutants (ZUST-1, ZUST-2), and used as PCR templates. H+-ATPase genes of the strain were amplified, and the PCR products were sequenced. Sequence similarity of H+-ATPase was analyzed. Real-time RT-PCR was used to evaluate the relative quantification of the H+-ATPase genes expression. Results: The growth of the mutants was characterized in MRS broth, which revealed that their cell biomass and acid production were lower than that of the wild-type. H+-ATPase activity of the mutants ZUST-1 and ZUST-2 was 10.1% and 28.8% lower than that of the wild-type. Results showed that atpA gene of the mutants ZUST-1 and ZUST-2 existed 22 mutations by alignment of the wild-type sequence, and atpC gene of ZUST-2 existed 6 mutations. Mutants ZUST-1 and ZUST-2 atpA gene expression were 41.1% and 35.7% lower than that of the wild-type in exponential phase, 43.6% and 14.2% in stationary phase, respectively. The atpC gene expression of ZUST-1 was similar to that of the wild-type in exponential phase, and was 30% higher than that of the wild-type in stationary phase, and ZUST-2 atpC gene was not expressed. Conclusion: The mutants with lower H+-ATPase activity were found to up-regulate the expression of H+-ATPase genes in stationary phase, except ZUST-2 atpC gene was not expressed. H+-ATPase activity has an important connection with the difference in gene expression of atpA and atpC. The results of this study will pave the way for gaining further insights into the mechanism of the H+-ATPase-defective mutants.

Antioxidant Capacities of Fractions of Bamboo Shaving Extract and Their Antioxidant Components.

This research was conducted for evaluation of antioxidant activities of four fractions from bamboo shavings extract (BSE) and their antioxidant components. The antioxidant capacities of BSE and four fractions on ABTS, DPPH, FRAP and total antioxidant capacity assays exhibited the following descending order: DF > n-butanol fraction (BF) > BSE ≈ ethyl acetate fraction (AF) > water fraction (WF). Among the identified phenolic compounds, caffeic acid exhibited the highest antioxidant capacities on DPPH, FRAP and total antioxidant capacity assays. An extremely significant positive correlation between the antioxidant activities with the contents of total flavonoids, total phenolic acids, or total phenolics was observed in this study. The result indicated that the bamboo shaving extract and its solvent fractions could act as natural antioxidants in light of their potent antioxidant activities.

Study of the rapid detection of γ-aminobutyric acid in rice wine based on chemometrics using near infrared spectroscopy.

Rice wine, in which γ-aminobutyric acid is present, is beneficial to human health and is one of the three most well-known fermented wines in the world, and is very popular in China. The rapid detection of γ-aminobutyric acid was studied in rice wine using near infrared spectroscopy with an optical fibre probe. Through the selection of detection conditions, including a waveband range of 12500-4000 cm(-1), a scanning duration of 16 scans and a resolution of 8 cm(-1), the near infrared spectrum of rice wine was acquired three times, for every wine sample, with an optical fibre probe. The resulting average value of the spectrum was obtained and the corresponding data were analysed via normalization. By adopting a multivariate calibration partial least squares method (PLS) and establishing a calibration model, the highest precision for γ-aminobutyric acid in rice wine was predicted when the factor coefficient was 17. The overall results demonstrating the content of γ-aminobutyric acid in rice wine was predicted to be between 157.6696-317.5813 mg/L, with a relative standard deviation of prediction between 0.01-5 %, as well as the fact that the single sample measuring time was less than 20 s, prove that near infrared spectroscopy is a rapid, accurate and effective method to adopt for detecting the content of γ-aminobutyric acid in rice wine.

Effects of secukinumab and ixekizumab on major adverse cardiovascular events in patients with psoriasis: a meta-analysis of randomized controlled trials.

Introduction: The aims of this study is to analyze the risk of major adverse cardiovascular events (MACEs) in patients with psoriasis treated with secukinumab and ixekizumab. Methodology: We systematically identified randomized controlled trials (RCTs) that focused on the treatment of psoriasis with secukinumab and ixekizumab by conducting computerized searches of PubMed, Embase, and the Cochrane Library databases, spanning from their inception to October 31st, 2022. The search terms used included psoriasis, secukinumab, ixekizumab, and randomized controlled trial. Two independent evaluators conducted literature screening, data extraction, and assessed the quality of included studies based on predetermined inclusion and exclusion criteria. The gather data was subjected to meta-analysis using the statistical software RevMan 5.4. Results: A total of 20 articles, encompassing 23 randomized controlled trials involving 10,746 psoriasis patients were included in the analysis. During the double-blind treatment period, the meta-analysis results indicated the following: There was no significant difference in the incidence of MACEs between the secukinumab and placebo groups [RR = 0.61, 95% CI (0.26, 1.44), p = 0.26]. Similarly, there was no significant difference in the incidence of MACEs with ixekizumab compared to the placebo group [RR = 0.47, 95% CI (0.15, 1.47), p = 0.20]. Furthermore, no significant difference in the incidence of MACEs was observed between secukinumab 300 mg and secukinumab 150 mg treatment groups [RR = 1.00, 95% CI (0.23, 4.35), p = 1.00]. Likewise, there was no significant difference in the incidence of MACEs between the ixekizumab Q4W (every 4 weeks) and ixekizumab Q2W (every 2 weeks) administration groups [RR = 4.01, 95% CI (0.45, 35.89), p = 0.21]. Conclusion: The findings of this study suggest that neither secukinumab nor ixekizumab is significantly associated with the risk of MACEs in patients with psoriasis during double-blind treatment.Systematic review registration: Unique Identifier: CRD42022373756 https://www.crd.york.ac.uk/.

Analysis of non-covalent interaction between ß-lactoglobulin and hyaluronic acid under ultrasound-assisted treatment: Conformational structures and interfacial properties.

Hyaluronic acid (HA) used as a food ingredient is gaining acceptance and popularity. However, the studies available for the effect of HA concentrations on the properties of ß-lactoglobulin (ß-LG) were limited. In this study, we investigated that the molecular characterization and functional properties of the complex formed by the non-covalent binding of ß-LG and HA, as well as the ultrasound-assisted treatment at acidic pH. The optimal pH and ratio of ß-LG/HA were set as 7 and 4:1, respectively. The fluorescence spectroscopy, circular dichroism spectroscopy, and molecular docking results revealed that the addition of HA and ultrasound induced a decrease in random coil and α-helix and an increase in ß-sheet contents in ß-LG. By the complexation with HA, the thermal stability, freezing stability, and antioxidant properties of ß-LG were all improved under ultrasound treatment. The results of the present study can be useful for the modulation of HA based biopolymer complexes and the exploitation as encapsulating or structuring agents in food industry.

Effects of thermal treatment on the formation and properties of whey protein isolate/whey protein hydrolysate-sodium hyaluronate complexes.

In dairy products, the added sodium hyaluronate may form complexes with proteins, thereby affecting product properties. In the present study, the interaction between whey protein isolate (WPI)/ whey protein hydrolysate (WPH) and sodium hyaluronate (SH) was characterized under thermal treatment at different temperatures (25 ℃, 65 ℃, 90 ℃ and 121 ℃) after studying effects of protein/SH ratio and pH on complex formation. The addition of SH reduced the particle size of WPI/WPH and increased potential value in the system, with greater variation with increasing treatment temperature. The structural properties of complexes were studied. The binding with SH decreased the contents of free amino group and free thiol group, as well as the fluorescence intensity and surface hydrophobicity. FTIR results and browning intensity measurement demonstrated the formation of Maillard reaction products. Moreover, the attachment of SH improved the thermal stability of WPI/WPH and decreased their antigenicity.

Effects of ultrasound and thermal treatment on the interaction between hyaluronic acid and lactoferrin: Preparation, structures and functionalities.

Complexes of polysaccharides and proteins have superior physicochemical and functional properties compared to single proteins or polysaccharides. In this study, lactoferrin-hyaluronic acid (LF-HA) complexes were prepared by both ultrasonic and thermal treatment. Appropriate preparation conditions, including ultrasonic and thermal treatment conditions, have been established. The complexes formed by different methods were structurally characterized by sodium dodecyl sulfate polyacrylamide gel electrophoresis, fourier transform infrared spectroscopy, and circular dichroism spectroscopy. Ultrasound formed non-covalent binding, while thermal treatment generated covalent bonding, altering the structure of LF. The LF-HA complexes showed improved heat stability, foaming stability, emulsifying activity and antioxidant capacity, but deceased foaming ability. Iron binding ability could only be improved by HA through thermal treatment. Moreover, the in vitro digestibility of LF-HA complexes decreased to below 80 % compared to LF.

Characterization of ultrasound-assisted covalent binding interaction between ß-lactoglobulin and dicaffeoylquinic acid: Great potential for the curcumin delivery.

The low bioavailability and poor gastrointestinal instability of curcumin hampers its application in pharmaceutical and food industries. Thus, it is essential to explore efficient carrier (e.g. a combination of polyphenols and proteins) for food systems. In this study, covalent ß-lactoglobulin (LG)-dicaffeoylquinic acids (DCQAs) complexes were prepared by combining ultrasound and free radical induction methods. Covalent interactions between LG and DCQAs were confirmed by analyzing reactive groups. Variations in secondary or tertiary structure and potential binding sites of covalent complexes were explored using Fourier transform infrared spectroscopy and circular dichroism. Results showed that the ß-sheet content decreased and the unordered content increased significantly (P < 0.05). The embedding rate of curcumin in prepared LG-DCQAs complexes using ultrasound could reach 49 % - 62 %, proving that complexes could embed curcumin effectively. This study highlights the benefit of ultrasound application in fabrication of protein-polyphenol complexes for delivering curcumin.

The phenolics, antioxidant activity and in vitro digestion of pomegranate (Punica granatum L.) peels: an investigation of steam explosion pre-treatment.

Pomegranate peels, the main byproduct of pomegranate production, are rich in phenolic compounds that are known for their effective antioxidant properties and have vast application prospects. In this study, steam explosion, an environmentally friendly technique, was applied to pretreat pomegranate peels for phenol extraction. We investigated the effects of explosion pressure, duration, and particle size on the content of total and individual phenolics, and antioxidant activity of pomegranate peels before and after in vitro digestion. The optimal conditions for a steam explosion for pomegranate peels in terms of total phenol content were a pressure of 1.5 MPa, a maintenance time of 90 s, and a particle size of 40 mesh. Under these conditions, pomegranate peel extract presented a higher yield of total phenols, gallic acid, and ellagic acid. However, it also had a lower content of punicalin and punicalagin, compared to the unexploded peels. There was no improvement in the antioxidant activity of pomegranate peels after the steam explosion. Moreover, the content of total phenol, gallic acid, ellagic acid, punicalin, and punicalagin, as well as the antioxidant activity of pomegranate peels, all increased after gastric digestion. Nevertheless, there was a large variation in the pomegranate peel processed by different pressure, duration, and sieve fractions. Overall, this study demonstrated that steam explosion pre-treatment could be an efficient method for improving the release of phenolics, especially gallic acid, and ellagic acid, from pomegranate peels.

High efficiency biosynthesis of gardenia blue and red pigment by lactic acid bacteria: A great potential for natural color pigments.

Current production methods of the food colorants, gardenia blue (GB) and red (GR) pigments have low efficiency. One potential approach involves using lactic acid bacteria (LAB), which produce a high level of ß-glucosidase, produce the GB and GR using non-toxic and harmless process. The isolated strain Lactobacillus plantarum S3 and the reference strain Lb. plantarum KCTC3104 showed high ß-glucosidase activity levels of 1.01 and 1.44 unit/mL, respectively. The 12-h bioconversion yield of geniposide to genipin using two strains were 93.4% and 100%, respectively, which are high conversion percentage. For GB, the maximal production yield obtained using Lb. plantarum S3 and Lb. plantarum KCTC3104 under optimal conditions were 2.17 and 2.18 mg/mL, respectively. For GR, glutamic acid (Glu) with Lb. plantarum S3 is the best combination. To the best of our knowledge, this is the first report of an effective alternative method for the production of natural food colorants using LAB.

New Insights into Phospholipid Profile Alteration of Bigeye Tuna (Thunnus obesus) during Daily Cooking Processes Using Rapid Evaporative Ionization Mass Spectrometry.

Bigeye tuna (BET, Thunnus obesus) is one of the most nutritious and luxurious cosmopolitan fish. The cooked BET products are capturing the interests of consumers by enhancing flavor and ensuring microbiological safety; however, the lipidomic fingerprints during daily cooking processes have not been investigated. In this work, lipid phenotypic data variation in BET during air-frying, roasting, and boiling was studied comprehensively using iKnife rapid evaporative ionization mass spectrometry (REIMS). The outstanding lipid ions mainly including fatty acids (FAs) and phospholipids (PLs) were identified structurally. It was demonstrated that the rates of heat transfer and lipid oxidation in air-fried BET were slower than those in roasted and boiled BET by elucidating the lipid oxidation and PL hydrolysis mechanism. Furthermore, multivariate REIMS data analysis (e.g., discriminant analysis, support vector machine, neutral network, and machine learning models) was used to characterize the lipid profile change in different cooked BET samples, among which FAC22:6, PL18:3/22:6, PL18:1/22:6, and others were the salient contributing features for determining the cooked BET samples. These results may provide a potential strategy for a healthy diet by controlling and improving functional food quality in daily cooking.

Sonochemical effects on fabrication, characterization and antioxidant activities of ß-lactoglobulin-chlorogenic acid conjugates.

The ß-lactoglobulin-chlorogenic acid (LG-CA) conjugate was explored to be formed through ultrasonication, redox-pair method and their combination, the ultrasonication used a probe ultrasonic machine with a 6 mm probe at 270 W, and the frequency was 20-25 kHz. The formation of the conjugate was confirmed by SDS-PAGE with a larger molecular weight. Besides, Fourier infrared spectroscopy (FTIR) and Circular dichroism (CD) indicated changes in the secondary structure of the LG-CA conjugate. The α-helix and ß-sheet contents of LG decreased and the unordered content increased significantly after the formation of covalent complexes. In addition, both the ultrasonic treatment and its combination with redox-pair method could significantly improve the antioxidant properties of LG. The former increased to 23.16 µmol Trolox/g sample, the latter 82-106 µmol Trolox/g sample. Therefore, ultrasonication could be used both individually and in combination with the redox-pair method to produce LG-CA conjugates with stronger antioxidant activities.

Lipidomic fingerprinting of plasmalogen-loaded zein nanoparticles during in vitro multiple-stage digestion using rapid evaporative ionization mass spectrometry.

Plasmalogens (Pls) as the hydrophobic bioactive compound have shown potential in enhancing neurological disorders. However, the bioavailability of Pls is limited because of their poor water solubility during digestion. Herein, the hollow dextran sulfate/chitosan - coated zein nanoparticles (NPs) loaded with Pls was prepared. Subsequently, a novel in situ monitoring method utilizing rapid evaporative ionization mass spectrometry (REIMS) coupled with electric soldering iron ionization (ESII) was proposed to assess the lipidomic fingerprint alteration of Pls-loaded zein NPs during in vitro multiple-stage digestion in real time. A total of 22 Pls in NPs were structurally characterized and quantitatively analyzed, and the lipidomic phenotypes at each digestion stage were evaluated by multivariate data analysis. During multiple-stage digestion, Pls were hydrolyzed to lyso-Pls and free fatty acids by phospholipases A2, while the vinyl ether bond was retained at the sn-1 position. The result revealed that the contents of Pls groups were significantly reduced (p < 0.05). The multivariate data analysis results indicated that the ions at m/z 748.28, m/z 750.69, m/z 774.38, m/z 836.58, and etc. were the significant candidate contributors for monitoring the variation of Pls fingerprints during digestion. Results demonstrated that the proposed method exhibited potential for real-time tracking the lipidomic characteristics of nutritional lipid NPs digestion in the human gastrointestinal tract.

Assessing the effect of powder characteristics of infant milk on the compressibility of milk powder compression molding.

Infant formula is an important food for those infants who are deprived of breast milk. However, infant formula powder is prone to fly apart, moisture absorption, sticky spoon, and inaccurate measurement. Block infant formula can solve these problems well. In this study, the characteristics (including particle structure morphology, moisture content, particle size, etc.) of infant formula powder were investigated on the compressive strength and solubility of block infant formula after compression molding with infant formula powder as the object. The results showed that the compressive strength and solubility of the block infant formula made from milk powder with a moisture content of 4.75%, particle size larger than 80 mesh, and morphology of compact grape structure appendages were the best. Therefore, milk powder with this characteristic is the most suitable for the preparation of block infant formula. This study provides referenceable experimental data and theoretical basis for the preparation and application of block infant formula.

Degradation, isomerization and stabilization of three dicaffeoylquinic acids under ultrasonic treatment at different pH.

Dicaffeoylquinic acids (diCQAs) are found in a variety of edible and medicinal plants with various biological activities. An important issue is the low stability of diCQAs during extraction and food processing, resulting in the degradation and transformation. This work used 3,5-diCQA as a representative to study the influence of different parameters in ultrasonic treatment on the stability of diCQAs, including solvent, temperature, treatment time, ultrasonic power, duty cycle, and probe immersion depth. The generation of free radicals and its influence were investigated during the treatment. The stability of three diCQAs (3,5-diCQA, 4,5-diCQA and 3,4-diCQA) under the certain ultrasonic condition at different pH conditions was evaluated and found to decrease with the increase of pH, further weakened by ultrasonic treatment. Ultrasound was found to accelerate the degradation and isomerization of diCQAs. Different diCQAs showed different pattern of degradation and isomerization. The stability of diCQAs could be improved by adding epigallocatechin gallate and vitamin C.

Ultrasound-assisted assembly of ß-lactoglobulin and chlorogenic acid for non covalent nanocomplex: fabrication, characterization and potential biological function.

It is essential to understand the ultrasound-induced changes in assembly of proteins and polyphenols into non covalent nanocomplex. ß-Lactoglobulin (LG) and chlorogenic acid (CA) with various biological activities can be combined to form food-grade nanocomplexes. This study systematically explored the role of high-intensity ultrasound pretreatment on the binding mechanisms of LG and CA, and the potential biological function for embedding curcumin (Cur). The scanning electron microscopy (SEM) revealed that ultrasound treatment could destroy the structure of LG, and the particle size of the protein was reduced to<50 nm. The change in secondary structure of the protein by ultrasound treatment could be revealed by the fourier transform infrared (FTIR) and fluorescence spectra. Besides, it was found that LG and CA were combined to form a complex under the hydrophobic interaction, and CA was bound in the internal cavity of LG with a relatively extended conformation. The result demonstrated that the ratio of Cur embedded in the ultrasonic sample could be effectively increased by 7% - 10%, the particle size in the emulsion was smaller, and the dispersion was more stable. This work contributes to the development of protein-polyphenol functional emulsion systems with the ability to deliver Cur.

Role Medium-Chain Fatty Acids in the Lipid Metabolism of Infants.

Human breastmilk, the ideal food for healthy infants, naturally contains a high concentration of medium-chain fatty acids (MCFAs, about 15% of total fatty acids). MCFAs are an important energy source for infants due to their unique digestive and metabolic properties. MCFA-enriched oils are widely used in an infant formula, especially the formula produced for preterm infants. Recently, there has been a growing interest in the triglyceride structure of MCFAs in human milk, their metabolism, and their effects on infant health. This study summarized the MCFA composition and structure in both human milk and infant formula. Recent studies on the nutritional effects of MCFAs on infant gut microbiota have been reviewed. Special attention was given to the MCFAs digestion and metabolism in the infants. This paper aims to provide insights into the optimization of formulations to fulfill infant nutritional requirements.