Interaction of exopolysaccharide produced by Lactobacillus plantarum YW11 with whey proteins and functionalities of the polymer complex

Exopolysaccharide (EPS)-producing lactic acid bacteria have been widely used in fermented milk, but interaction between the EPS and milk proteins has not been well studied. In this study, interaction between the EPS from Lactobacillus plantarum YW11 (EPS-YW11) and whey proteins (WP), and functional properties of the EPS-YW11/WP were investigated. The results showed that EPS-YW11 tended to encase WP by ζ-potential analysis with a decrease in the surface charge of the protein fraction (from −26.00 mV to 15.30 mV), and an increase in the melting temperature of the protein fraction (from 76.31 °C to 84.48 °C) as shown by differential scanning calorimetry. Circular dichroism spectrometry showed that the EPS could induce structural change of WP, that is, increment in the content of α-helixes and random coils, There was stronger interaction between EPS-YW11 and WP at higher temperatures (60 °C, 90 °C) due to formation of intermolecular H-bonds and OH stretching vibration as indicated by infrared spectral analysis. A significant improvement in the texture (hardness, springiness, gumminess, resilience, cohesiveness, and chewiness) of the EPS-YW11/WP complex was also observed when compared to that of the EPS or WP alone. This was confirmed by microstructural observation of the EPS-YW11/WP complex that formed branched and porous structures, and it became more complex and stable with increased temperature treatment. Due to the strong interaction the EPS-YW11/WP exhibited improved functionality. This study identifies the potential of the EPS-YW11 to serve as a functional agent in the processing of fermented dairy products with enhanced textural stability and bioactivities such as cholesterol-lowering, antioxidant, and antibiofilm.     

Growth and aflatoxin production by Aspergillus parasiticus in a medium at different pH values and with or without pimaricin

A glucose-yeast extract-salt medium containing 0, 5, 7.5, 10, 15 or 20 micrograms pimaricin/ml with an initial pH of 3.5 or 5.5 was inoculated with Aspergillus parasiticus WB 108 and incubated at 15 degrees or 28 degrees C. The pH, weight of mycelium and amount of aflatoxin produced were determined after 3, 7, and 10 days and after 14, 21, and 30 days when incubation was at 28 degrees or 15 degrees C, respectively. Increasing the concentration of pimaricin in the medium with an initial pH of 5.5 decreased the amounts of aflatoxin B1 and G1 produced after 3 days of incubation. When the initial pH of the medium was 3.5, no growth or toxin production occurred after 3 days of incubation in the medium containing 7.5 micrograms or more of pimaricin/ml. The presence of 20 micrograms of pimaricin/ml inhibited growth and toxin production after 7 days of incubation. When cultures were incubated at 15 degrees C, there was a lag phase which extended from 9 to 16 days, and the amounts of aflatoxin produced decreased with an increasing concentration of pimaricin. Pimaricin did not completely inhibit the growth and aflatoxin production by A. parasiticus. Pimaricin, in combination with a low pH, low temperature or 4% or 6% NaCl, initially caused slow mycelial growth and low toxin production, but the mold overcame the inhibitory effects and produced substantial amounts of mycelium and toxin.     

Conservation characteristics of corn ears and stover ensiled with the addition of Lactobacillus plantarum MTD-1, Lactobacillus plantarum 30114, or Lactobacillus buchneri 11A44

The aim of this study was to investigate the effects of inoculating 3 contrasting lactic acid bacteria on the fermentation profile, estimated nutritive value, and aerobic stability of corn ears and stover produced under marginal growing conditions. Ears and stover were separated from whole-crop corn plants obtained from 3 replicate field blocks. Representative subsamples were precision chopped and allocated to 1 of the following treatments: an uninoculated control, Lactobacillus plantarum MTD-1 (LP1), L. plantarum 30114 (LP2), or Lactobacillus buchneri 11A44 (LB). Each bacterial additive was applied at a rate of 1 × 10(6) cfu/g of fresh herbage. Triplicate samples of each treatment were ensiled in laboratory silos at 15°C for 3, 10, 35, or 130 d. No difference was observed between the dry matter recoveries of uninoculated ear or stover silages and silages made with LP1, and the aerobic stability of uninoculated ear and stover silages did not differ from silages made with LB. Stover silages made with LP2 and ensiled for 35 d had a lower proportion of lactic acid in total fermentation products compared with LP1. The aerobic stability and dry matter recovery of ear and stover silages in this study were not improved when made with LB, LP1, or LP2, due to the indigenous highly heterolactic fermentation that prevailed in the uninoculated ear and stover during 130-d ensilage.     

Survival of Lactobacillus casei,Lactobacillus plantarum and Bifidobacterium bifidum in free and microencapsulated forms on Iranian white cheese produced by ultrafiltration

Survival of probiotic strains Lactobacillus casei ( ATCC 39392 ), Lactobacillus plantarum ( ATCC 8014 ) and Bifidobacterium bifidum ( ATCC 29521 ) was investigated either in microencapsulated or in free form in the Iranian white cheese produced by ultrafiltration technique. The results indicated that the survival of encapsulated probiotic bacteria was higher than free cells. Both free and microencapsulated forms were successful in keeping counts of L. casei, L. plantarum and B. bifidum in the cheese high enough for the therapeutic minimum (10⁶–10⁷ cfu/g) after 60 days. Addition of probiotic adjunct also did not alter the chemical composition, but pH was lower in probiotic cheeses.     

Physicochemical,textural and volatile characteristics of fermented milk co-cultured with Streptococcus thermophilus,Bifidobacterium animalis or Lactobacillus plantarum

Fermented milks were prepared with various culture combinations of Lactobacillus plantarum or Bifidobacterium animalis with Streptococcus thermophilus, and the impact of microbes combinations on acidification, proteolysis, lipolysis, texture, volatiles and sensory quality of fermented milk was investigated during 21-day storage at 4 °C. The results showed that products from the co-cultures displayed higher titratable acidity, more peptides, higher proteolytic activity and lipolysis capacity compared with that from the pure strains of S. thermophilus. When L. plantarum and B. animalis combined in a ratio of 2:1 with S. thermophilus, the products maintained relatively more viable cell counts of the 3 strains, strong proteolysis ability and lipolysis capacity during the storage. Milk fermented by co-cultures of the 3 strains exhibited higher cohesiveness, more volatiles and better sensory quality compared with these fermented by S. thermophilus only or in co-cultures with either B. animalis or L. plantarum based on principal component analysis.     

Chemotaxis toward carbohydrates and peptides by mixed ruminal protozoa when fed,fasted, or incubated with polyunsaturated fatty acids

In contrast to the well-characterized chemotaxis and migratory behavior between the dorsal and ventral locations of the rumen by isotrichids, we hypothesized that chemotaxis toward soluble nutrients maintains entodiniomorphid protozoa in the particulate fraction. The objectives of these experiments were to compare the dose-responsive chemotaxis (1) toward different glucose concentrations when ruminal samples were harvested from fed versus fasted cows; (2) toward increasing concentrations of glucose compared with xylose when protozoa were harvested from a fed cow; (3) toward peptides of bacterial, protozoal, and soy origin; and (4) toward glucose when mixed ruminal protozoa were previously incubated for 0, 3, or 6 h in the presence of emulsified polyunsaturated fatty acids (PUFA; Liposyn II, Hospira, Lake Forest, IL). In experiment 1, isotrichid protozoa decreased chemotaxis toward increasing glucose concentration when cows were fasted. Entodiniomorphids exhibited chemotaxis to similar concentrations of glucose as did isotrichids, but to a lesser magnitude of response. In experiment 2, xylose was chemotactic to both groups. Xylose might draw fibrolytic entodiniomorphid protozoa toward newly ingested feed. In contrast, even though isotrichids should not use xylose as an energy source, they were highly chemoattracted to xylose. In experiment 3, entodiniomorphids were not selectively chemoattracted toward bacterial or protozoal peptides compared with soy peptides. In experiment 4, despite isotrichid populations decreasing in abundance with increasing time of incubation in PUFA, chemotaxis to glucose remained unchanged. In contrast, entodiniomorphids recovered chemotaxis to glucose with increased time of PUFA incubation. Current results support isotrichid chemotaxis to sugars but also our hypothesis that a more moderate chemotaxis toward glucose and peptides explains how they swim in the fluid but pass from the rumen with the potentially digestible fraction of particulates.     

Mode of action, purification and amino acid sequence of plantaricin C19, an anti-Listeria bacteriocin produced by Lactobacillus plantarum C19.

Plantaricin C19, an anti-Listeria bacteriocin, was successfully purified by adsorption to and release from producing cells at low pH combined with reverse phase high-performance liquid chromatography (HPLC). The purification resulted in a 900-fold increase in specific activity with a yield of 15% of the original activity. Mass spectrometry analysis gave a molecular weight of 3845.3. Protein microsequencing identified 36 amino acids. Plantaricin C19 is rich in both hydrophobic and basic amino acids in good accordance with its basic and hydrophobic character. Comparison of the amino acid sequence of plantaricin C19, with the sequence of some other anti-Listeria bacteriocins produced with lactic acid bacteria, revealed that plantaricin C19 has in its N-terminal region the consensus sequence--YYGNGL--(uniquely with Valine instead of Leucine as found in all other bacteriocins), identifying plantaricin C19 as a pediocin-like bacteriocin. Plantaricin C19 exerted a bacteriostatic action on sensitive cells of Listeria grayi IP 6818 in BHI broth. No loss of intracellular K+, Mg2+ or UV-absorbing materials was observed. Adsorption of plantaricin C19 on L. grayi CIP 6818 decreased in the presence of salts.     

Isolation and preliminary characterization of a bacteriocin produced by Lactobacillus plantarum N014 isolated from nham, a traditional Thai fermented pork

Lactobacillus plantarum N014 was isolated from nham, a traditional Thai fermented pork, and exhibited antimicrobial activity against Listeria monocytogenes. Its bacteriocin had a broad inhibitory spectrum toward both gram-positive and gram-negative bacteria. The bacteriocin activity was sensitive to all proteolytic enzymes used in this study, including papain, pepsin, pronase E, proteinase K, and trypsin, but was resistant to the other enzymes, such as alpha-amylase, lipase A, and lysozyme. Furthermore, activity was stable over various heat treatments and pH values. The bacteriocin exerted a bacteriolytic mode of action. It was produced during the exponential growth phase and reached its highest level as producer cells entered the stationary phase. Adsorption of the bacteriocin onto producer cells was pH-dependent. No bacteriocin adsorption was detected at pH 1 to 3, whereas 100% bacteriocin adsorption was found at pH 7. Plasmid isolation revealed that L. plantarum N014 contained no plasmids. From Tricine-sodium dodecyl sulfate-polyacrylamide gel electrophoresis and growth inhibition testing against L. monocytogenes, the estimated molecular mass of L. plantarum N014 bacteriocin was 8 kDa.     

Apoptosis in rabbit embryos produced by fertilization or nuclear transfer with fibroblasts and cumulus cells

In this study, we investigated the development, the cell number of the blastocyst, and apoptosis in rabbit nuclear transfer (NT) embryos derived from adult fibroblasts and cumulus cells as compared with embryos derived from in vivo fertilization and in vitro culture. The developmental rate and the total cell number of the blastocyst were significantly lower in NT embryos than in fertilized embryos (FEs). The type of donor cells did not affect the embryonic developmental rate and the total cell number of blastocysts in NT groups. The present study investigated the onset and the frequency of apoptosis in NT embryos and FEs by using a terminal deoxynucleotidyl transferase-mediated dUTP nick and labeling (TUNEL) assay. The earliest positive TUNEL signals were detected at the eight-cell stage in NT embryos and at the morula stage in FEs. The apoptotic index of the total blastocysts, the inner cell mass and the trophoderm was greatly higher in the NT embryos than in FEs. Moreover, the apoptotic index of the blastocyst from fibroblasts was significantly higher than that of the blastocyst from cumulus cells.     

Energy content, sensory properties, and microbiological shelf life of German bologna-type sausages produced with citrate or phosphate and with inulin as fat replacer

ABSTRACT:  The aim of this study was to determine the feasibility of reducing energy content (9% to 48%) in bologna-type sausages by replacing fat with inulin and to study the effects of substituting citrate for phosphate in the traditional sausage formula. German-type mortadella was produced, and fat was replaced with increasing amounts of inulin as a frozen gel to yield 3%, 6%, 9%, and 12% inulin in the final product. In another part of the study, citrate was substituted for the phosphate in the recipe. All sausages produced were sliced, packaged under a modified atmosphere (70% N₂, 30% CO₂), and stored for 23 d at +7 °C. Sausage quality was determined by chemical and instrumental texture profile analyses, color measurement, sensory evaluation, and microbiological testing. Replacing fat with inulin led to significant energy content reductions of up to 47.5% (with 12% inulin). However, the sensory properties of these sausages were also different from those of the control mortadella: fracturability fell, hardness and adhesiveness rose, and color became darker. In general, the substitution of citrate for phosphate significantly reduced the negative effects of inulin. There were no significant differences in microbiological stability between different inulin batches but there were significant differences between phosphate and citrate batches. Overall, the energy content of bologna-type sausages produced with citrate and with up to 6% inulin as a fat replacer was 22% lower than that of the control sausages. Furthermore, the sensory attributes (texture, color) of these 6% inulin–citrate sausages were comparable to the control sausages, and the sausages were microbiologically stable for 23 d of storage.     

HPLC-柱后光化学衍生法检测花生酱中黄曲霉毒素

建立高效液相色谱-在线柱后光化学衍生-荧光检测器检测花生酱中黄曲霉毒素B1、B2、G1、G2的含量。样品以乙腈-水(80∶20)溶液提取,经免疫亲和柱净化后,利用在线柱后光化学衍生-HPLC-FLD进行分析测定。结果:在优化条件下,黄曲霉毒素B1、G1在0.30 mg/L~10 mg/L,黄曲霉毒素B2、G2在0.06 mg/L~3.0mg/L线性关系良好,r0.998,回收率80%~101%,RSD5.9%。黄曲霉毒素B1、B2、G1、G2的检测限(LOD)分别为0.10、0.03、0.15、0.04μg/kg。     

Chemical analysis and sensory evaluation of Cheddar cheese produced with Lactobacillus acidophilus,Lb. casei,Lb. paracasei or Bifidobacterium sp.

The sensory properties of probiotic Cheddar cheeses made using Lactobacillus acidophilus 4962, Lb. casei 279, Bifidobacterium longum 1941, Lb. acidophilus LAFTI^® L10, Lb. paracasei LAFTI^® L26 or B. lactis LAFTI^® B94 were assessed after ripening for 9 months at 4 °C. Probiotic cheeses except those with Lb. acidophilus 4962 were significantly different (P<0.05) from the control without any probiotic organism. Acceptability of probiotic cheese with Lb. casei 279 was significantly lower (P<0.05) than that of the control cheese with bitterness and sour-acid taste as the major defects. Concentration of acetic acid in probiotic cheeses was higher (P<0.05) than the control cheese. Vinegary scores did not influence the acceptability of the cheeses (P>0.05). Increased proteolysis in probiotic cheeses did not influence the Cheddary attribute scores (P>0.05). There were positive correlations (P<0.05) between the scores of bitterness and the level of water-soluble nitrogen.     

Microbial, instrumental color and sensory color and odor characteristics of ground beef produced from beef trimmings treated with ozone or chlorine dioxide

The effects of beef trimming decontamination with ozone and chlorine dioxide on ground beef microbial, color and odor characteristics were studied. Beef trimmings were inoculated with Escherichia coli (EC) and Salmonella Typhimurium (ST), then treated with either 1% ozonated water for 7 min (7O) or 15 min (15O), or with 200 ppm chlorine dioxide (CLO) and compared with a control (C). Trimmings were ground, packaged and sampled at 0, 1, 2, 3 and 7 days of display for EC, ST, coliforms (CO), aerobic plate counts (APC), instrumental color, as well as sensory color and odor characteristics. The 15O and CLO treatments reduced (P<0.05) all bacterial types evaluated, whereas the 7O treatment reduced (P<0.05) APC and ST. All treatments caused ground beef to become lighter (L*) in color (P<0.05); however, the 15O treatment was similar (P>0.05) in redness (a*), percentage discoloration, beef odor and off odor intensities when compared to C.     

Intraspecific diversity of Lactobacillus curvatus, Lactobacillus plantarum, Lactobacillus sakei, and Leuconostoc mesenteroides associated with vacuum-packed meat product spoilage analyzed by randomly amplified polymorphic DNA PCR

The intraspecific diversity of Leuconostoc mesenteroides, Lactobacillus curvatus, Lactobacillus sakei, and Lactobacillus plantarum was analyzed by randomly amplified polymorphic DNA (RAPD) PCR with universal primers M13 and T3. The study included 100 reference strains and 210 isolates recovered from two vacuum-packed Spanish meat products, fiambre de magro adobado and morcilla, previously identified by rDNA-restriction fragment length polymorphism profiles. The RAPD-M13 profiles identified isolates at species level in L. plantarum and L. mesenteroides, while RAPD-T3 provided profiles in L. sakei. The combination of RAPD-M13 and RAPD-T3 fingerprints revealed a total of 17 profiles in L. mesenteroides, 6 in L. sakei, 12 in L. plantarum, and 6 in L. curvatus. Of these, six profiles corresponding to L. mesenteroides and one corresponding to L. sakei were found in both products. The Shannon-Weaver diversity index (H'), calculated according to RAPD-M13 and RAPD-T3 profiles during storage, revealed that most profiles appeared only in single samplings in both products, indicating a high strain substitution rate during chilled storage of vacuum-packed meat products. When bloating appeared, only one profile corresponding to L. mesenteroides subsp. dextranicum was present throughout the storage period.     

Physicochemical Properties,Fatty Acid Profiles,and Sensory Characteristics of Fermented Beef Sausage by Probiotics Lactobacillus plantarum IIA‐2C12 or Lactobacillus acidophilus IIA‐2B4

Probiotics may be used to enhance the functionality and nutritional values of fermented sausages. This study aims to evaluate the physicochemical and sensory properties of beef sausages fermented by lactic acid bacteria of Lactobacillus plantarum IIA‐2C12 and L. acidophilus IIA‐2B4. These strains were isolated from beef cattle and have shown to display probiotic features. While the nutrient contents were not affected by the probiotics, the pH, texture, and color varied among the sausages. Further analysis on fatty acids showed different profiles of saturated (C14:0, C17:0, and C20:0) and unsaturated (C14:1, C18:1n9c, C18:2n6c, and C22:6n3) fatty acids in sausages with probiotics. Gas chromatography–mass spectrometry further revealed some flavor development compounds including acid, alcohols, aldehydes, aromatic, ketones, sulfur, hydrocarbons and terpenes, varied among the sausages. Hedonic test showed no difference in the preference toward aroma, texture, and color for untrained panelists.     

Effects of gassericins A and T, bacteriocins produced by Lactobacillus gasseri, with glycine on custard cream preservation

Lactobacillus gasseri LA39 and LA158 isolated from human-infant feces produce bacteriocins named gassericins A and T, respectively. Both gassericins have high heat stability (121°C, 10 min), good pH tolerance (pH 2-11), and strong bactericidality against many gram-positive bacteria, especially lactic acid bacteria, and thus are expected to be effective food preservatives. A microwell plate assay against 12 strains of custard cream spoilage bacteria showed that the gassericins had broader antibacterial spectra than nisin A. Although the gassericins allowed gram-negative isolates to grow, they successfully inhibited the growth of all tested bacterial strains in microwells with the addition of glycine. Glycine was bacteriostatic against many strains except lactic acid bacteria. For practical use, gassericin A was efficiently produced by cultivation in a food-grade medium improved using cheese whey, nourishing proteose peptone, and surfactant yolk lecithin. The practical preservative effect of gassericin A and glycine was verified from the viability of 4 isolated strains, Bacillus cereus, Lactococcus lactis ssp. lactis, Achromobacter denitrificans, and Pseudomonas fluorescens, in custard creams. Custard cream containing 123 arbitrary units of gassericin A per milliliter entirely growth-inhibited the 2 gram-positive strains. In custard cream containing an insufficient amount of gassericin A (49 arbitrary units/mL), the gram-positive strains gradually grew but were completely inhibited by the addition of 0.5% (wt/wt) glycine. The 2 gram-negative strains did not multiply even in the additive-free custard cream, probably because of the unsuitable growth environment. This is the first report showing the combined effect of bacteriocin and glycine and their application for food preservation, which may be helpful for future use in the food industry.     

Characterization of a 3944 Da bacteriocin, produced by Enterococcus mundtii ST15, with activity against Gram-positive and Gram-negative bacteria

Strain ST15, isolated from soy beans, and identified as Enterococcus mundtii, produces a 3944 Da bacteriocin that inhibits the growth of Lactobacillus sakei, Enterococcus faecalis, Bacillus cereus, Propionibacterium sp., Clostridium tyrobutyricum, Acinetobacter baumanii, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus pneumoniae and Streptococcus caprinus. Bacteriocin ST15 is inactivated by proteinase K, pronase, pepsin, protease and Triton X-114, but not when treated with catalase, alpha-amylase, Triton X-100, SDS, Tween 20, Tween 80, urea and EDTA. No change in activity was recorded after 2 h at pH values between 2.0 and 12.0, and after treatment at 100 degrees C for 90 min. Activity was, however, lost after treatment at 121 degrees C for 20 min. The mode of activity is bactericidal. The highest level of activity (51200 AU ml(-1)) was recorded when cells were grown in MRS broth, pH 6.5. Bacteriocin ST15 differs from other broad-spectrum bacteriocins described for Enterococcus spp. by being active against Gram-negative bacteria and by being smaller.     

Simultaneous Determination of Aflatoxin B1, Bisphenol A,and 4-Nonylphenol in Peanut Oils by Liquid-Liquid Extraction Combined with Solid-Phase Extraction and Ultra-High Performance Liquid Chromatography-Tandem Mass Spectrometry

An analytical method based on liquid-liquid extraction combined with solid-phase extraction and isotope dilution-ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was well developed for simultaneous determination of aflatoxin B1 (AFB1), bisphenol A (BPA), and 4-nonylphenol (4-NP) in peanut oil. After adding isotope internal standards, the samples were firstly diluted by normal hexane and then extracted by acetonitrile and Carb/PSA solid-phase extraction cartridge in sequence to obtain the extracted solution. All the extracted solution was merged and was subsequently dried to near dryness by a mild nitrogen stream. Three target analytes were separated on a Phenomenex Luna C18 chromatographic column, quantified by an internal standard method and detected by ESI positive (ESI⁺) and negative (ESI^?) subsection acquisition modes under multi-reaction monitoring (MRM) conditions. Results demonstrated that the three target analytes exhibited excellent linearity in their corresponding concentration ranges of 0.1–100.0 μg/L with correlation coefficients all greater than 0.998. The corresponding method limits of quantitation (MLOQ, S/N?=?10) of AFB1, BPA, and 4-NP were 0.2, 1.0, and 2.0 μg/kg, respectively. Moreover, the mean recoveries for negative samples spiked at three concentration levels were calculated between 87.7 and 105.1% with relative standard deviation (RSD, n?=?6) ranging from 2.2 to 7.9% and the interday precision (n?=?5) ranging from 5.0 to 8.7%. Finally, the method was successfully applied to analyze 52 peanut oil samples, and AFB1 and 4-NP were detected in 43 samples with the concentrations in the ranges of 0.5–69.4 and 9.3–77.8 μg/kg, respectively. None of BPA was detected in any samples.     

Detection of guaiacol produced by Alicyclobacillus acidoterrestris in apple juice by sensory and chromatographic analyses, and comparison with spore and vegetative cell populations

Spoilage of fruit juice by Alicyclobacillus acidoterrestris is characterized by a distinct medicinal or antiseptic off odor attributed to guaiacol, a metabolic by product of the bacterium. Detection of low populations of A. acidoterrestris that would precede sensory detection of guaiacol would enable juice processors to select appropriate processing and storage conditions that would minimize or eliminate spoilage. The objective of this study was to determine the recognition threshold of guaiacol in apple juice by sensory analysis and the population of A. acidoterrestris and incubation time at 21 and 37 degrees C necessary for chemical detection of guaiacol. Commercially sterilized apple juice (pH 3.54 +/- 0.04, 11.3 +/- 0.3 degrees Brix) was inoculated with a five-strain mixture of A. acidoterrestris spores (2.98 log10 CFU/ml) and stored at 21 or 37 degrees C for up to 61 days. Using an experienced sensory panel and the forced-choice ascending concentration method of limits, the best estimate threshold (BET) for recognition of guaiacol added to uninoculated apple juice was 2.23 ppb. Numbers of A. acidoterrestris spores and cells in inoculated juice remained constant during the 61-day storage period; however, the panel detected (P < or = 0.01) guaiacol in juice stored at 37 degrees C within 8 days. At three of four sampling times ranging from 13 to 61 days at which the sensory panel detected (P < or = 0.001) guaiacol, concentrations of 8.1 to 11.4 ppb were detected by chromatographic analysis. The panel detected (P < or = 0.1 to P < or = 0.01) guaiacol in five samples stored at 21 to 37 degrees C for 8 to 61 days in which the compound was not detected by chromatographic analyses. It appears that guaiacol content in apple juice inoculated with A. acidoterrestris is not always correlated with numbers of cells, and the limit of sensitivity of chromatographic quantitation of the compound is higher than the BET.     

Feed intake and digestion by Holstein steers fed warm or cool season grass hays with corn, dried molasses, or wheat middlings.

This study determined the effects of adding a small amount of dried molasses to supplemental corn and of supplementing with corn, wheat middlings, or corn-wheat middlings mixture on intake and digestion by Holstein steers fed warn or cool season grass hays. Eight steers (175 kg BW), in two simultaneous Latin squares, were fed, once daily, bermuda-grass (72% NDF) or ryegrass-wheat (58% NDF) hay ad libitum, alone or with approximately .05% BW of dried molasses (with 31% roughage), 5% BW of ground corn, or both. Adding dried molasses to corn decreased feed intake but did not affect digestible OM intake. Total tract digestion of fiber from bermudagrass tended to be enhanced by adding dried molasses to corn. Eight steers (193 kg BW) were used in an experiment with the same design in which similar forages were fed alone or with corn (.5% BW), wheat middlings (.63% BW), or .25% BW of corn plus .31% BW of middlings. Feed intake for both grasses was similar among supplements. Wheat middlings depressed total tract fiber digestion more than corn with both forages. Supplementation with corn depressed fiber digestion slightly more with ryegrass-wheat than with bermudagrass, but wheat middlings had a slightly greater depressing effect on fiber digestion with bermudagrass. Associative effects of mixing corn and wheat middlings in OM digestion and digestible OM intake were negative for bermudagrass and positive for ryegrass-wheat. Interaction among characteristics of basal forage and concentrate modulated feed intake and digestion by ruminants.