Volatile organic compounds profile during milk fermentation by Lactobacillus pentosus and correlations between volatiles flavor and carbohydrate metabolism.

Flavor, as one of the most important properties determining the acceptability and preference of fermented milks, is influenced by compositional and processing factors. In this study, we focused on the volatile organic compounds related to flavor during milk fermentation by Lactobacillus pentosus according to electronic nose analysis. Xylose (1% addition) metabolized by Lb. pentosus strongly affects the flavor of yogurt, with the potent volatile organic compounds of ethanol (3.08%), 2,3-butanedione (7.77%), and acetic acid (22.70%) detected using solid-phase microextraction coupled with gas chromatography-mass spectrometry analysis. Sensoryanalysis also showed skimmed yogurt fermented by Lb. pentosus with 1% xylose had the unique scores of sourness (acetic acid) and butter flavor (2,3-butanedione). Furthermore, α-acetolactate synthase and α-acetolactate decarboxylase in carbohydrate metabolism play important roles in milk fermentation. Under preferable conditions (pH 5.5, 42 °C) for α-acetolactate synthase and α-acetolactate decarboxylase, the relative content of potent flavor compound 2,3-butanedione was 10.13%, which was 2.55% higher than common culture condition (pH 4.5, 37 °C), revealing that xylose metabolized by Lb. pentosus has potential values for the milk product industry, such as the acceptability and preference of fermented milk product.

Antialcoholic liver activity of whey fermented by Lactobacillus casei isolated from koumiss.

Whey fermented liquid (WFL) was studied for its hepatoprotective effects by using chronic alcohol-induced mice. Whey fermented liquid, prepared by inoculating whey with 4% (vol/vol) Lactobacillus casei and then incubating at 41°C for 8h, was used to orally treat alcohol-induced mice at 3 dosages for 5 wk. Ethanol consumption significantly reduced the activity of superoxide dismutase and glutathione peroxidase, while lowering glutathione content and increasing levels of aspartate aminotransferase, alanine aminotransferase, total triglyceride, malondialdehyde, and cytochrome P450 2E1. Treatment with WFL significantly attenuated the increased levels of alanine aminotransferase, aspartate aminotransferase, triglyceride, and cytochrome P450 2E1, while decreasing superoxide dismutase, glutathione peroxidase, malondialdehyde, and glutathione levels. Pathological changes in the livers of mice who had ingested alcohol were improved by the administration of WFL. These results suggest that WFL may exert a protective effect against alcoholic liver disease by increasing antioxidant activity, which supports the use of WFL as an antialcoholic liver disease treatment.

Immunomodulatory and hypoallergenic properties of milk protein hydrolysates in ICR mice.

Approximately 2.5% of young children are allergic to cow milk. In this study, milk protein hydrolysates made from full-cream milk via enzymatic hydrolysis played a positive role in regulating the immune system of ICR mice. Milk protein hydrolysates enhanced immunity in mice by stimulating host immunity, probably by increasing the weight of certain immune system organs, improving the level of hemolysin in serum, and enhancing the phagocytosis of macrophages. Milk protein hydrolysates have the capability to reduce type I hypersensitivity by decreasing IgE levels, IL-4 in serum, and the release of histamine and bicarbonate in peritoneal mast cells, as well as enhancing transforming growth factor-ß levels in the serum of ovalbumin-sensitized mice.

[Status of fungal sepsis among preterm infants in 25 neonatal intensive care units of tertiary hospitals in China].

Objective: To analyze the prevalence and the risk factors of fungal sepsis in 25 neonatal intensive care units (NICU) among preterm infants in China, and to provide a basis for preventive strategies of fungal sepsis. Methods: This was a second-analysis of the data from the "reduction of infection in neonatal intensive care units using the evidence-based practice for improving quality" study. The current status of fungal sepsis of the 24 731 preterm infants with the gestational age of <34+0 weeks, who were admitted to 25 participating NICU within 7 days of birth between May 2015 and April 2018 were retrospectively analyzed. These preterm infants were divided into the fungal sepsis group and the without fungal sepsis group according to whether they developed fungal sepsis to analyze the incidences and the microbiology of fungal sepsis. Chi-square test was used to compare the incidences of fungal sepsis in preterm infants with different gestational ages and birth weights and in different NICU. Multivariate Logistic regression analysis was used to study the outcomes of preterm infants with fungal sepsis, which were further compared with those of preterm infants without fungal sepsis. The 144 preterm infants in the fungal sepsis group were matched with 288 preterm infants in the non-fungal sepsis group by propensity score-matched method. Univariate and multivariate Logistic regression analysis were used to analyze the risk factors of fungal sepsis. Results: In all, 166 (0.7%) of the 24 731 preterm infants developed fungal sepsis, with the gestational age of (29.7±2.0) weeks and the birth weight of (1 300±293) g. The incidence of fungal sepsis increased with decreasing gestational age and birth weight (both P<0.001). The preterm infants with gestational age of <32 weeks accounted for 87.3% (145/166). The incidence of fungal sepsis was 1.0% (117/11 438) in very preterm infants and 2.0% (28/1 401) in extremely preterm infants, and was 1.3% (103/8 060) in very low birth weight infants and 1.7% (21/1 211) in extremely low birth weight infants, respectively. There was no fungal sepsis in 3 NICU, and the incidences in the other 22 NICU ranged from 0.7% (10/1 397) to 2.9% (21/724), with significant statistical difference (P<0.001). The pathogens were mainly Candida (150/166, 90.4%), including 59 cases of Candida albicans and 91 cases of non-Candida albicans, of which Candida parapsilosis was the most common (41 cases). Fungal sepsis was independently associated with increased risk of moderate to severe bronchopulmonary dysplasia (BPD) (adjusted OR 1.52, 95%CI 1.04-2.22, P=0.030) and severe retinopathy of prematurity (ROP) (adjusted OR 2.55, 95%CI 1.12-5.80, P=0.025). Previous broad spectrum antibiotics exposure (adjusted OR=2.50, 95%CI 1.50-4.17, P<0.001), prolonged use of central line (adjusted OR=1.05, 95%CI 1.03-1.08, P<0.001) and previous total parenteral nutrition (TPN) duration (adjusted OR=1.04, 95%CI 1.02-1.06, P<0.001) were all independently associated with increasing risk of fungal sepsis. Conclusions: Candida albicans and Candida parapsilosis are the main pathogens of fungal sepsis among preterm infants in Chinese NICU. Preterm infants with fungal sepsis are at increased risk of moderate to severe BPD and severe ROP. Previous broad spectrum antibiotics exposure, prolonged use of central line and prolonged duration of TPN will increase the risk of fungal sepsis. Ongoing initiatives are needed to reduce fungal sepsis based on these risk factors.

The probiotic properties of Lactobacillus buchneri P2.

AIMS: To isolate new lactobacilli strain with cholesterol-lowering effect and analyse its probiotic properties and possible mechanisms of cholesterol removal. METHODS AND RESULTS: The strain with cholesterol-lowering effect was isolated from pickled juice. The acid and bile tolerance and antimicrobial activity were tested. The free cholalic acid, the cholesterol in supernatant fluid, washing buffer and cell extract, the cholesterol removed by growing, dead and resting cells were quantified. The isolated strain with high cholesterol-reducing rate of 43.95% was identified as Lactobacillus buchneri (Lact. buchneri) P2. It had acid and bile tolerance and antimicrobial activity. Moreover, it could remove cholesterol via coprecipitating with deconjugated bile salts, assimilating and adsorbing by cells. And the assimilation was considered to be the main reason of cholesterol removal. CONCLUSIONS: The isolated Lact. buchneri P2 showed probiotic properties of cholesterol reduction, acid and bile tolerance and antimicrobial activity and could remove cholesterol via different ways. SIGNIFICANCE AND IMPACT OF THE STUDY: A new strain of Lact. buchneri P2 with efficient cholesterol-reducing ability was isolated to provide species diversity of lactobacilli for functional dairy products. And the possible mechanism of cholesterol removal by Lact. buchneri was discussed.

The effect of ultrasound treatments on the tenderizing pathway of goose meat during conditioning.

In order to figure out the effect of ultrasound treatments (UT) on the tenderizing pathway of goose meat, breast muscles of 32 Eastern Zhejiang White Geese were treated with different ultrasound powers (the control, 300 and 600 W) at 40 kHz for 30 min. Shear force, cooking loss, myofibrillar fraction index (MFI), particle size, morphological analysis of actin filaments and the levels of F-actin and G-actin were investigated during 168 h storage. Results showed that 600 W group had the lowest shear force and cooking loss at 24, 48, 96 and 168 h among treatments, while 300 W UT decreased shear force and cooking loss compared to the control. UT increased MFI and induced myofibrillar small particles (D3,2) by disrupting actin filaments for myofibril and transforming of F-actin to G-actin compared to the control. We concluded that UT tenderized goose meat by fragmenting actin filaments and myofibrillar fraction.

The effect of structural change on the digestibility of sarcoplasmic proteins in Nanjing dry-cured duck during processing.

To evaluate the effect of structural change on the digestibility of sarcoplasmic proteins in Nanjing dry-cured duck during processing, carbonyl content, sulfhydryl (SH) group, disulfide (S-S) group, surface hydrophobicity, particle size, secondary structures, and in vitro digestibility were determined. During processing, carbonyl content increased; SH groups turned into S-S groups; α-helix turned into ß-sheet. From marinating to early dry-ripening stage, surface hydrophobicity increased but particle size decreased, whereas these had opposite tendencies at the late dry-ripening stage. The in vitro digestibility of pepsin decreased at drying-curing and drying-ripening stages, whereas the one of pancreatic proteases kept stable until late drying-ripening stage. We concluded that salting, drying, and protein oxidation caused the denaturation and aggregation during processing. The oxidation and aggregation of sarcoplasmic proteins of Nanjing dry-cured duck resulted in a loss of nutritional quality during drying-ripening stage.

The change of volatile compounds of two kinds of vinasse-cured ducks during processing.

Vinasse-cured duck was processed by boiling, salting, and vinasse-dry-curing or vinasse-wet-curing. Volatile compounds, moisture contents, reducing sugars, and thiobarbituric acid reactive substances (TBARS) values during processing were determined. Reducing sugars decreased during boiling and increased after vinasse-curing. TBARS values increased throughout the processing. The volatiles of ducks during processing and vinasse-curing agents (dry vinasse and vinasse sauce) were 125 compounds. The first principal component (PC1) belonged to the flavor of cooked duck, whereas the second principal component (PC2) represented the flavor of yellow rice wine. The 66.49 and 29.61% of typical aroma of vinasse-dry-cured product were from dry vinasse and lipid oxidation, respectively, whereas the 75.58 and 21.89% of aroma of vinasse-wet-cured product were from vinasse sauce and lipid oxidation, respectively. Lipid oxidation products increased after boiling, whereas salting promoted their release. Compared with vinasse-wet-cured duck, vinasse-dry-cured product presented richer aroma of lipid oxidation and weaker flavor of vinasse-curing agents. Besides, protein denaturation which was caused by ethanol could influence the retention and release of flavor. In conclusion, two kinds of vinasse-curing methods influenced the characteristic volatiles of products and their generation during processing.

Effect of pH on the interaction of volatile compounds with the myofibrillar proteins of duck meat.

In order to clarify the influence of curing agents on the flavor of duck, the effect of pH on the surface hydrophobicity, secondary structures, and adsorption capacity of myofibrillar proteins to alcohols, aldehydes, ketones, and esters was assessed using Raman spectroscopy, gas chromatography-mass spectrometer, and other methodologies. The hydrophobicity decreased as pH increased from 5.0 to 8.0; ß-turn turned into α-helix and random coil as pH increased from 5.0 to 7.0, while α-helix and random coil turned into ß-sheet and ß-turn as pH increased from 7.0 to 8.0. With the increase of pH, the decreased adsorbing of alcohols could depend on hydrogen bonds. As pH increased from 5.0 to 8.0, the increase of aldehydes and esters was attributed to the unfolding of myofibrillar proteins and decreased hydrophobicity. The decreased adsorbing of ketones was due to the decreased hydrophobicity as pH increased from 5.0 to 8.0. The present work provided information about the correlation between structure and adsorption capacity of myofibrillar proteins to flavor compounds.

The effect of dry-cured salt contents on accumulation of non-volatile compounds during dry-cured goose processing.

Twenty-four Eastern Zhejiang White Geese were slaughtered, dry-cured by 2 different kinds of salt contents (12 geese with 4% low salt level [LS]; 12 geese with 8% high salt level [HS]) for one d, marinated in brine for one d, and air dry-ripened at 16 °C for 7 d. The effect of dry-curing salt contents on the changes in myofibril proteins, potential proteolysis activities, and total free amino acid (TFAA) in dry-cured goose was investigated. Compared to the raw, cathepsin B+L and calpains activities decreased at the end of dry-curing and the third d of dry-ripening. At the final products, the activities of cathepsin B+L and calpains were about half of those in raw meat. There was no difference in proteolysis activities except for the end of dry-curing (P < 0.05) and the 3 d of dry-ripening (P < 0.05) for cathepsin B+L, and the end of dry-curing (P < 0.05) for calpains (P < 0.05) between groups. Myosin light chain (MLC) and troponin-I were cleaved. Compared to the raw, TFAA increased by 36.64 and 31.82% in the final products for HS (P < 0.001) and LS (P < 0.01), respectively. The increase of TFAA could be attributed to the proteolysis of myofibril proteins and retained proteolysis activities. No significant difference on TFAA and MLC and troponin-I bands was observed between groups in final products. This means that different proteolysis activities during processing did not cause the difference in quality of final products between groups, and that 4% low salt can be used in future applications.

Digital replantation. A ten-year retrospective study.

Eight hundred and two digits (592 complete amputation and 210 incomplete amputations) of 549 patients were replanted. The male to female ratio was 3:1 and the age range 1-63 years. 728 digits survived and 74 digits failed. The overall survival rate was 90.8%. Special varieties of complicated amputation were encountered in this series: (1) distal segment replantation, 139 digits, 131 digits (94%) survived; (2) digital replantation of children, 45 cases, 78 digits, average age 3.8 years, the youngest being 1 year old, 68 digits survived (88.7%); (3) rotational avulsion amputation of thumb, 26 digits, 23 digits (88.4%) survived; (4) bilateral digit amputation, 8 cases, 44 digits amputated, 38 digits replanted, including 9 digits of a ten-digit guillotined case. All the digits were salvaged. We conclude that thorough debridement, meticulous anastomosis of blood vessels and timely management of vascular crisis are keys to high survival rate, while judicious selection of indication, proper internal fixation of bone, anastomosis of as many blood vessels as possible, attentive repair of nerves and tendons, sound rehabilitation program are important measures in improving postoperative function.

Activation of caspase-3 and its correlation with shear force in bovine skeletal muscles during postmortem conditioning.

The study was aimed at exploring the mechanism of tenderization by establishing a correlation between caspase-3 activity and shear force, verifying the activation occurring by analyzing active caspase-3 and cleaved poly (ADP-ribose) polymerase (PARP) fragments, and understanding the pathways involved in activation of caspase-3 by evaluating its correlation with caspase-8 and -9 activities in LM, semitendinosus (STN), and psoas minor (PM) muscles. The results indicated that shear force decreased at 48 h in PM (P < 0.01), LM (P < 0.01), and STN (P < 0.05). We detected p22, p23, p20, and p18 caspase fragments as well as distinctive PARP fragments of 24 kDa by caspase-3 and 36 kDa by µ-calpain. Caspase-3 activity correlated with shear force negatively at 24 and 48 h in STN (P < 0.01 at 24 h; P < 0.01 at 48 h), PM (P < 0.001 at 24 h; P < 0.01 at 48 h), and LM muscles (P < 0.05 at 24 h; P < 0.01 at 48 h). The greatest activities of caspase-8 (P < 0.001 in PM and STN; P < 0.01 in LM) and caspase-9 (P < 0.001 in muscles) appeared at 4 h whereas that of caspase-3 was at 24 h (P < 0.001 in muscles). Caspase-9 activity correlated positively with caspase-3 at 4, 24, and 48 h in STN (P < 0.01 at 4 h; P < 0.05 at 24 h; P < 0.001 at 48 h) and at 4 and 96 h in PM (P < 0.001 at 4 h; P < 0.05 at 96 h) and LM muscles (P < 0.001 at 4 h; P < 0.001 at 96 h). The caspase-8 activity correlated with caspase-3 at 4, 48, and 96 h in STN (P < 0.05 at 4 h; P < 0.001 at 48 h; P < 0.05 at 96 h), at 4 and 24 h in PM (P < 0.001 at 4 h; P < 0.05 at 24 h), and at 4 and 96 h in LM (P < 0.001 at 4 h; P < 0.01 at 96 h). We concluded that caspase-3 was associated with the decline of shear force; the activation of caspase-3 was mediated by caspases -8 and -9 in muscles. However, more detailed studies are needed to define the precise mechanism for the cleavage of pro-caspases -8 and -9 during conditioning.

Internal structure of normal maize starch granules revealed by chemical surface gelatinization.

Normal maize starch was fractionated into two sizes: large granules with diameters more than 5 microns and small granules with diameters less than 5 microns. The large granules were surface gelatinized by treating them with an aqueous LiCl solution (13 M) at 22-23 degrees C. Surface-gelatinized remaining granules were obtained by mechanical blending, and gelatinized surface starch was obtained by grinding with a mortar and a pestle. Starches of different granular sizes and radial locations, obtained after different degrees of surface gelatinization, were subjected to scanning electron microscopy, iodine potentiometric titration, gel-permeation chromatography, and amylopectin branch chain length analysis. Results showed that the remaining granules had a rough surface with a lamella structure. Amylose was more concentrated at the periphery than at the core of the granule. Amylopectin had longer long B-chains at the core than at the periphery of the granule. Greater proportions of the long B-chains were present at the core than at the periphery of the granule.

Transplantation of severed digits to forearm stump for restoration of partial hand function.

Three cases of mutilating injury of the distal end of the forearm, wrist, and palm treated by transplantation of severed digits to the forearm stump are reported. Follow-up examinations made at 1 year and 4 months to 31/2 years postoperatively revealed fair sensory and motor functions. The functional result is better than that obtained after Krukenberg's operation or prosthesis fitting, and is comparable to that of "hand" reconstruction by autotransplantation of toes. Since this procedure can fulfill the basic requirements of hand function by reconstruction, namely, good sensibility; basic motor functions of pinching, grasping, and powerful gripping; and acceptable outward appearance, and can be accomplished in a one-stage operation without sacrificing toes, it should be considered as first choice whenever a suitable case is encountered.