Qiuqin Zhang

The spoilage of air-packaged broiler meat during storage at normal and fluctuating storage temperatures

Bacterial diversity and the major flora present on air-packaged broiler meat during storage at normal (4°C) and fluctuating storage temperatures (0-4°C and 4-10°C) were investigated using culture-dependent and culture-independent approaches. Culture-dependent analysis revealed that the growth of microflora was retarded when broiler meat was stored at lower temperatures (0-4°C). Denaturing gradient gel electrophoresis profiles showed that Staphylococcus spp., Pseudomonas spp., Acinetobacter spp., Carnobacterium spp., Aeromonas spp., and Weissella spp. were the dominant bacteria throughout all storage conditions. Enterobacteriaceae only appeared in samples subjected to storage with high temperature abuse, whereas Shewanella spp. and Psychrobacter spp. were only detected in samples stored below 4°C. Our results provide evidence that, compared with storage at a standard fixed temperature (4°C), fluctuations in temperatures induce a more complex bacterial diversity in the air-packaged broiler.

Activation of caspase-9 and its influencing factors in beef during conditioning.

To study the activation of caspase-9 and its potential influence in conditioning, longissimus thoracis (LT), semitendinosus (STN) and psoas minor (PMi) muscles were used to analyze the ratio of pro-apoptotic bax to anti-apoptotic bcl-2 in fresh tissues and observe the changes in ATP, cytosolic cytochrome c and caspase-9 activity levels during storage at 4°C. Caspase-9 activity at 5 h is higher than the activity at 0 and 24 h in the muscles (P<0.001). The ATP content decreased between 0 and 3 h, between 8 and 14 h in the PMi and LT muscles (P<0.0001), whereas between 0 and 5 h, between 8 and 14 h in the STN muscle (P<0.0001). There is 60.2%, 55.3% and 43.1% available ATP in the STN, LT and PMi muscles at 5 h, respectively. The cytosolic cytochrome c level increased during 5 and 24 h storage in the LT and PMi muscles (P<0.0001), during 5 and 96 h in the STN muscle (P<0.0001). The cytosolic cytochrome c at 24 h (P<0.001) and ratio of bax to bcl-2 (P<0.05) was higher in the PMi than in other muscles. We concluded that the increase in cytosolic cytochrome c and available intracellular ATP should be responsible for the increase in caspase-9 activity; the activation of caspase-9 could be limited by the subsequent depletion of ATP; the postmortem release level of cytochrome c could be determined by the ratio of bax to bcl-2 in fresh tissues.

Structural characterization and antioxidant property of released exopolysaccharides from Lactobacillus delbrueckii ssp. bulgaricus SRFM-1

Three released exopolysaccharide fractions (r-EPS1, r-EPS2 and r-EPS3) were isolated from the fermented milk of Lactobacillus delbrueckii ssp. bulgaricus SRFM-1 and purified by anion exchange chromatography, and characterizations of the structures were conducted. The r-EPS1 and r-EPS2 were homogenous with the average molecular weights of 3.97×105Da and 3.86×105Da, respectively. Three r-EPS fractions were composed of galactose and glucose with a molar ratio of 1.23: 1.00, 1.33: 1.00 and 1.00: 1.34, respectively. Structural characterization indicated that the r-EPS1 contained a backbone of →6-β-d-Galp-(1→4)-β-d-Glcp-(1→4)-α-d-Galp-(1→4)-β-d-Galp-(1→6)-β-d-Galp-(1→4)-β-d-Glcp-(1→4)-α-d-Galp-(1→4)-β-d-Galp-(1→4)-α-d-Glcp-(1→, and had three branching points which existed in terminal with D-Glcp residues with α/β-d-(1→6) linkages. The r-EPS2 was composed of →6-β-d-Galp-(1→4)-β-d-Glcp-(1→6)-α-d-Galp-(1→ as the backbone chain with a branching point which also existed in terminal D-Glcp residue with β-(1→6) linkage. In addition, three r-EPS fractions exhibited strong scavenging activities on superoxide radical, hydroxyl radical, DPPH radical and chelating activity on ferrous ion, and their antioxidant activities decreased in the order of r-EPS1>r-EPS2>r-EPS3.

The identification of c-Kit-positive cells in the intestine of chicken

The ultrastructure of the interstitial cells of Cajal (ICC) has been examined in birds, but the distribution of these cells remains obscure because a suitable marker is lacking. In the present study, the identification and expression of c-Kit-positive cells in the chicken intestine were demonstrated by means of in situ hybridization histochemistry and the expression of the c-Kit gene by real-time quantitative PCR. Two types of cells stained positive for c-Kit mRNA. The first group consisted of spindle-shaped or bipolar cells identified as ICC. The ICC were found at a variety of locations: at the level of the myenteric plexus between the circular and longitudinal muscle and intermingled with smooth muscle cells within muscle bundles in the circular and longitudinal muscle layers. The ICC were also identified along the submucosal layer. The second group was composed of round-shaped cells, which resembled mast cells. Mast cells were mainly found in the lamina propria region as well as in the submucosal layer. The expression of the c-Kit gene by real-time quantitative PCR revealed the expression of c-Kit mRNA throughout the lamina muscularis and mucosa of the intestine; however, the quantitation was variable in different regions. This study reveals conclusively for the first time the distribution of ICC, quantifies the expression of c-Kit mRNA in the intestine of adult chicken, and also compares the c-Kit-positive cell types morphologically.

Characterization of the ultrastructure in the uterovaginal junction of the hen.

In poultry, the infundibulum is the place of fertilization, eggshell production, and sperm storage, while its uterovaginal junction (UVJ) is regarded as the most important site, which has abundant sperm storage tubules (SST). We examined the ultrastructure of the epithelium with relation to its unique secretory cytology in the UVJ of hens using transmission electron microscopy. The epithelium of the UVJ is lined with ciliated and secretory cells. Ciliated cells are characterized with light and dense secretory granules in supernuclear cytoplasm. Dense secretory granules in ciliated cells are larger in diameter (onexa0μm), surrounded with a transparent rim and concentric layers, whereas the dense granules in the ciliated cells of SST are smaller (0.52xa0μm) in size and not surrounded by any transparent rim or layer. Ciliated cells also are involved in the shedding of exosomes and secretory vesicles in the lumen. Secretory exosomes are in close contact with cilia and directly release from the apical border into the lumen. Cell junctions are widely distributed between these cells. The secretory cells are associated with the release of secretions via apocrine blebs from microvilli and secretory vesicles, which protrude out from the surface of the epithelium. The dense secretory granules in these cells are smaller in size (0.6xa0μm), absent of a transparent rim or layers, and are released into the lumen through secretory vesicles. The intracellular multivesicular body (MVB) also is observed in the supernuclear cytoplasm of secretory cells, which are related to the production of exosomes. In general, the apical protrusion of the epithelium in the form of apocrine secretions, the releasing of exosomes, the identification of intracellular MVB, and the release of dense granules give the epithelium a distinct morphology in the UVJ of the hen oviduct.

Does lactic fermentation influence soy yogurt protein digestibility: a comparative study between soymilk and soy yogurt at different pH: Lactic fermentation influence soy yogurt protein digestibility

BACKGROUNDnLactic acid bacteria fermentation allows soymilk to form a yogurt-like product accompanied by protein acidic coagulation. It is not known whether the coagulation of soy protein during fermentation influences protein digestibility when ingested. In the present study, soymilk (pH 6.3) and soy yogurt (SY) at different pH (6.0, 5.7, 5.4 and 5.1) were subjected to in vitro gastrointestinal digestion (GIS) and a comparison study was conducted.nnnRESULTSnLactic fermentation allowed the pH of soymilk to reduce gradually to 5.1 in 330.0 min. A decline in pH resulted in the volume-weighted mean diameters D[4,3] and D[v,90] increasing from 0.81 to 97 µm and 1.82 to 273 µm, respectively. Predominant proteins lost their solubility between pH 6.0 and 5.7. Application of GIS allowed SY samples, especially SY-5.7, SY-5.4 and SY-5.1, to reveal particles with a predominant peak at approximately 10 µm and also lower soluble proteins compared to soymilk, with reduction percentages of 18%, 28% and 43%. The cleavage pattern of soy protein during GIS was scarcely affected by the sample pH. However, a lower quantity of the band at 33.9 kDa was found in SY-5.7, SY-5.4 and SY-5.1.nnnCONCLUSIONnThe results of the present study demonstrate that lactic fermentation altered soy protein digestibility. With the process of protein coagulation, SY-5.7, 5.4 and 5.1 had a lower bioaccessible protein content compared to that of soymilk.

Ultrasonic-assisted Aqueous Extraction and Physicochemical Characterization of Oil from Clanis bilineata

Ultrasound-assisted aqueous extraction (UAAE) was used to extract oil from Clanis bilineata (CB), a traditional edible insect that can be reared on a large scale in China, and the physicochemical property and antioxidant capacity of the UAAE-derived oil (UAAEO) were investigated for the first time. UAAE conditions of CB oil was optimized using response surface methodology (RSM) and the highest oil yield (19.47%) was obtained under optimal conditions for ultrasonic power, extraction temperature, extraction time, and ultrasonic interval time at 400 W, 40°C, 50 min, and 2 s, respectively. Compared with Soxhlet extraction-derived oil (SEO), UAAEO had lower acid (AV), peroxide (PV) and p-anisidine values (PAV) as well as higher polyunsaturated fatty acids contents and thermal stability. Furthermore, UAAEO showed stronger antioxidant activities than those of SEO, according to DPPH radical scavenging and β-carotene bleaching tests. Therefore, UAAE is a promising process for the large-scale production of CB oil and CB has a developing potential as functional oil resource.

Effects of Cordyceps militaris (L.) Fr. fermentation on the nutritional, physicochemical, functional properties and angiotensin I converting enzyme inhibitory activity of red bean (Phaseolus angularis [Willd.] W.F. Wight.) flour

The effects of solid-state fermentation with Cordyceps militaris (L.) Fr. on the nutritional, physicochemical, and functional properties as well as angiotensin I converting enzyme (ACE) inhibitory activity of red bean (Phaseolus angularis [Willd.] W.F. Wight.) flour were determined. Fermentation increased the amount of small peptides but significantly decreased large peptides. Fermentation also increased proteins and essential amino acids (by 9.31 and 13.89%, respectively) and improved the in vitro protein digestibility (6.54%) of red beans. Moreover, fermentation increased the water holding capacity (from 2.36 to 2.59xa0mL/g), fat absorption capacity (from 84.65 to 114.55%), emulsion activity (from 10.96 to 52.77%), emulsion stability (from 5.43 to 53.82%), and foaming stability (from 11.95 to 20.68%). Fermented red bean flour achieved a lower least gelation concentration of 14% than that of the control (18%). In contrast to the non-fermented red bean, the fermented red bean showed ACE inhibitory activity, with IC50 value of 0.63xa0mg protein/mL. Overall, fermentation improved the nutritional, physicochemical, and functional properties as well as the biological activity of red bean flour. Thus, fermented red bean flour may serve as a novel nutritional and functional ingredient for applications in food design.

Solid-State Bioprocessing with Cordyceps militaris Enhanced Antioxidant Activity and DNA Damage Protection of Red Beans (Phaseolus angularis)

In this study, red beans were bioprocessed by using a novel solid-state fermentation (SSF) with an edible and medical filamentous fungus Cordyceps militaris. The effect of SSF on the total phenolic content (TPC), antioxidant activity, and DNA damage protection of red beans was determined. Furthermore, solvents with different polarities (80% methanol, 80% ethanol, 80% acetone, and deionized water) were used to extract antioxidant compounds from the red bean samples. The results indicated that SSF significantly enhanced TPC, 2,2-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt radical cation scavenging activity, reducing power, and chelating ability of red beans. Furthermore, this study also demonstrated that fermented red beans exhibited greater protection against oxidative DNA damage than nonfermented red beans. Besides, the water extract of fermented red beans showed the highest TPC, antioxidant activity, and DNA damage protection among the various extracts examined. For the specific phen...