JOURNAL OF FOOD BIOCHEMISTRY, Issue 1 2009
THUY T. PHAM
ABSTRACT The objective of this study was to assess the potential of pure ,-galactosidase and ,-glucosidase for hydrolyzing isoflavone glycosides to aglycones in soy milk. Both pure ,-galactosidase and ,-glucosidase were added at various concentrations (0.5, 1.0, 2.0 and 4.0 U/mL) to soy milk made from 4% soy protein isolate and incubated at 37C for up to 240 min. Isoflavones were quantified using high-performance liquid chromatography. The isoflavone contents of soy milk before and after autoclaving were also compared. ,-Glucosidase and ,-galactosidase were both able to hydrolyze the ,-glucosidic linkages in isoflavone glycosides. A range of 43.3 to 77.2% of the total isoflavone glycosides was hydrolyzed at various ,-galactosidase concentrations. The ,-glucosidase hydrolyzed isoflavone glycosides more efficiently than ,-galactosidase. At the most diluted ,-glucosidase concentration (0.5 U/mL), 86.6% of isoflavone glycosides were hydrolyzed to aglycones at 240 min. PRACTICAL APPLICATIONS Isoflavone glycosides, which are mainly found in the bean family, are the inactive forms of isoflavones. However, aglycones, which are the nonsugar component of a glycoside molecule that results from hydrolysis of the isoflavone glycosides, are the biologically active forms. Because of their similarity to female hormone, they are considered a "natural way" to relieve the menopausal symptoms as they prevent certain cancers and improve bone health. Only a small amount of the total isoflavones, however, exists in the aglycone forms in nature. A novel method to produce aglycones from natural isoflavones is highly important. ,-Glucosidase has been claimed to be the only enzyme which is able to hydrolyze isoflavone glycosides to aglycones. However, other enzymes could hydrolyze isoflavone glycosides more efficiently and could be easier to produce. This paper investigates the ability of ,-galactosidase to biotransform isoflavone glycosides to aglycones, as the source of the enzyme is abundant. [source]

EFFECT OF HIGH-PRESSURE TREATMENT OF MILK ON LIPASE AND ,-GLUTAMYL TRANSFERASE ACTIVITY

JOURNAL OF FOOD BIOCHEMISTRY, Issue 6 2004
P. K. PANDEY
ABSTRACT High-pressure (HP) treatment (0,180 min at 300,400 MPa) was applied to milk to evaluate the pressure effects on the activities of lipoprotein lipase and ,-glutamyl transferase. Short time pressure exposure resulted in some enhancement in the activity of both enzymes, and for lipase, there was no inactivation during the entire pressure hold time (up to 100 min). With ,-glutamyl transferase, the extent of enhancement in activity was pressure level dependent, with lower pressure resulting in a greater enhancement. Furthermore, longer pressure treatment times resulted in inactivation of ,-glutamyl transferase, following a first order kinetic model. The pressure sensitivity of the inactivation parameters (k and D -values) for ,-glutamyl transferase was adequately described by the pressure death time and Arrhenius models with a zpof 543 MPa and an associated volume of activation, ,V,, of ,3.28 × 10,8 m3/mole. [source]

DETERMINATION OF pH CHANGE KINETICS DURING DIFFERENT STAGES OF KASHAR CHEESE MANUFACTURING FROM RAW AND PASTEURIZED MILK WITH ADDITION OF THERMOPHILIC, MESOPHILIC AND MIXED THERMOPHILIC CULTURE

JOURNAL OF FOOD PROCESS ENGINEERING, Issue 4 2008
AHMET FERIT ATASOY
ABSTRACT The pH change kinetics during Kashar cheese production from raw and pasteurized milk with addition of thermophilic, mesophilic and mixed thermophilic-mesophilic lactic acid bacteria were evaluated. The kinetics of pH change were determined during milk ripening, cooking/holding and pressing/fermentation phases of Kashar cheese. The pH decreased logarithmically, nonlinearly, with time in the milk ripening period, and reduced linearly with time in the cooking/holding and pressing/fermentation stages. Pasteurization of milk retarded the rate of change in pH during the three periods. The highest rate of pH change was determined in the addition of thermophilic culture, followed by mixed thermophilic-mesophilic and then mesophilic ones during milk ripening. The pH change characteristics of cheese made with thermophilic starter were similar to the cheese made with mixed thermophilic-mesophilic culture, but different from mesophilic lactic acid bacteria during cooking/holding and pressing/fermentation stages. PRACTICAL APPLICATIONS One of the important factors in the control of cheese quality is the extent of acid production in the vat. Acid development at a desired rate is important during cheese making. The progress of acidification is monitored by pH change in the industrial Kashar cheese production. Three main stages have been recognized with respect to pH change: milk ripening, cooking/holding and pressing/fermentation. This study evaluated and compared the pH change kinetics during various stages of Kashar cheese making using raw, pasteurized milk with the addition of thermophilic, mesophilic and mixed thermophilic culture. This work may help in the comparison of raw and pasteurized milk, and in the selection of appropriate starter culture for Kashar cheese production. [source]

BAKING PROPERTIES OF MILK PROTEIN-COATED WHEAT BRAN,

JOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 1 2008
CHARLES I. ONWULATA
ABSTRACT Increasing the dietary fiber content of formulated foods will benefit the health and nutrition of consumers. The problem is that it is difficult to add substantial amounts of dietary fiber to formulated foods. Fiber absorbs significant amounts of water from surrounding ingredients creating texture problems such as soggy and dry patches in the foods. In this study, red wheat bran milled and sieved smaller than 140 microns was coated by spraying with a 50/50 emulsion of whey protein isolates (WPIs) and casein. WPI and casein emulsion was produced first by blending and shearing the milk proteins in ice and water and then evaporating under partial vacuum for 75 min at 45C. Cookies and muffins made with the milk protein-coated red wheat (MPCF) bran and the noncoated wheat bran (NCF), replacing 5, 10 and 15 wt % of the flour, were compared to control cookies and muffins made without added fiber. The water-holding capacity (WHC) of the MPCF and NCF was determined along with their moisture, color, hardness, and volume in the baked cookies and muffins. There was a significant (P < 0.01) improvement (250%) in loss of WHC of MPCF over NCF. In cookies, MPCF absorbed significantly less water and was slightly darker at 5 wt % substitution than NCF, but was between 12 to 60% higher in baked volume than the control. MPCF muffins were lighter in color and harder except for the 5 wt % muffins that were softer and higher in percent baked volume. Adding up to 15-g MPCF per 100 g batter can be added to baked cookies and muffins to increase fiber content and improve WHC and volume. PRACTICAL APPLICATIONS This study determined that coating wheat bran with specially treated dairy proteins reduced the amount of water the bran can absorb when added up to 15 wt% to formulations, or in the finished products, helping to maintain textural integrity of products. The intact wheat bran remains available for its functional health enhancing roles when consumed and digested. This knowledge allows the creation of nutritious high-fiber products with desirable texture. [source]

THERMAL INACTIVATION KINETICS OF ALKALINE PHOSPHATASE IN BUFFER AND MILK

JOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 3 2006
S. FADILO
ABSTRACT A detailed kinetic study on the thermal inactivation of alkaline phosphatase (ALP) added into buffer and pasteurized milk and for ALP naturally present in raw cow's milk has been performed. Kinetic parameters (rate constant, k; decimal reduction time, D; activation energy, Ea; and z value) were evaluated based on the first-order rate model at 50,80C. The temperature sensitivity of the kinetic parameters was evaluated considering the Arrhenius-type Ea model. All kinetic behaviors were well described by the first-order model (r2 > 0.91). The D values increased with increasing temperature. Higher temperatures resulted in higher rates of enzyme inactivation as indicated by lower D values and higher k values. There are significant differences (P < 0.01) among the D values for ALP in buffer and milk at treated temperatures. The rate of enzyme inactivation was much more rapid in buffer than in pasteurized milk. The evaluated Ea values for ALP added into the buffer and pasteurized milk, and for ALP naturally present in raw milk were 97.2, 149.9 and 207.8 kJ/mol, respectively. The inactivation kinetics of ALP during heat treatment was found to be dependent on the composition of the medium, and the time and temperature of the heat treatment. [source]

RHEOLOGY AND TEXTURE OF COMMERCIAL QUESO FRESCO CHEESES MADE FROM RAW AND PASTEURIZED MILK

JOURNAL OF FOOD QUALITY, Issue 2010
MICHAEL H. TUNICK
ABSTRACT Queso Frescos made in Mexico from raw milk (RM) were compared with cheeses made in Mexico and the U.S.A. from pasteurized milk (PM) to determine textural and rheological differences. RM cheese, considered the ideal Queso Fresco, contained more moisture than PM cheeses, displayed higher cohesiveness and shear strain and exhibited lower hardness and shear stress. The U.S.-made cheeses were harder and more brittle and crumbly than the Mexican cheeses. The shear stress decreased as fat content increased in all samples, and the shear strain decreased as the pH increased in the Mexican cheeses. An understanding of the differences between the RM and PM versions should allow cheese makers to adjust manufacturing procedures so that PM Queso Fresco cheeses will meet consumer expectations. PRACTICAL APPLICATIONS Hispanic cheeses such as Queso Fresco are gaining in popularity in the U.S.A. The milk for making Queso Fresco in the U.S.A. must be pasteurized, and the resulting cheese is perceived by some consumers to be inferior in flavor and texture to the traditional variety made from raw milk. Queso Fresco samples made in Mexico from both kinds of milk and made in the U.S.A. from pasteurized milk were analyzed to see if there were differences in texture, structure, and the ability to twist and break pieces of the cheese. The cheeses made in the U.S.A. contained less moisture and were too hard, crumbly, and brittle when compared to the raw milk cheeses. The differences observed should enable U.S. companies to make Queso Fresco with properties close to those of the raw milk variety. [source]

OPTIMIZATION OF SPRAY DRYING CONDITIONS FOR PRODUCTION OF BIFIDUS MILK POWDER FROM COW MILK

JOURNAL OF FOOD QUALITY, Issue 4 2006
M. SELVAMUTHUKUMARAN
ABSTRACT Bifidus milk powder was prepared by supplementing cow's milk with predetermined level of additives to obtain slurry of desired concentration. The slurry was sterilized, cooled and inoculated with 24-h-old bulk culture of Bifidobacterium bifidum at 10% and incubated at 37C for 24 h, cooled and dried in SM Scientech Lab model spray dryer with predetermined spray drying conditions. The bifidus milk powder contains bifidobacteria counts from 1.88 × 109 to 15.80 × 109 cells/g dry weight and their percent survival was 4.17,35.11%. Maximum survival was obtained by using the following spray drying conditions: inlet temperature of 164.02C, slurry concentration of 25.62% total soluble solids and air pressure of 2.5 kg/cm2. The high temperature and air pressure of spray drying markedly influenced the color and appearance of final product. The inlet temperature and air pressure showed a significant effect on survival of bifidobacteria in the final product. [source]

DETECTION OF COW MILK IN BUFFALO "MOZZARELLA" BY POLYMERASE CHAIN REACTION (PCR) ASSAY

JOURNAL OF FOOD QUALITY, Issue 6 2004
ANGELA DI PINTO
ABSTRACT The authors used a polymerase chain reaction (PCR) assay on buffalo mozzarella, a typical Italian dairy product, from the Apulia markets to evaluate the presence of cow milk and verification of the mozzarella label. The results obtained from 30 mozzarella samples demonstrated the presence of the cow genome in 22/30 samples, highlighting contamination as probable fraudulent adding of cow's milk or use of the same equipments in both working cycles. [source]

IMPROVED MEDIUM FOR DETECTION OF KLEBSIELLA IN POWDERED MILK

JOURNAL OF FOOD SAFETY, Issue 1 2010
HONG GAO
ABSTRACT The selectivities to pathogenic Klebsiella strains of different isolation media were compared by known standard strains. The modified MacConkey-inositol-carbenicillin (MCIC) medium (Named MCIAC, MacConkey-inositol-adonitol-carbenicillin) supplemented with adonitol gave no false-negative colonies, and exhibited higher selectivity. MCIC and Simmons citrate agar with inositol (SCAI) media gave two false-negative colonies, respectively. These three media all gave two false-positive colonies, respectively. Salmonella Shigella medium gave four false-negative colonies and five false-positive colonies. Violet red bile glucose agar medium gave the most false-positive colonies, although it gave no false-negative colonies. One hundred samples of powdered milk were examined by MCIAC, MCIC and SCAI plates. The typical positive colonies were further identified using Vitek GNI Auto Microbic system and API 20E system. The results showed that the specificity of the MCIAC medium was higher than MCIC and SCAI media. PRACTICAL APPLICATIONS MacConkey-inositol-carbenicillin (MCIC) is the most commonly used selective medium for the detection of Klebsiella. But some inositol-nonfermenting Klebsiella strains would be missed when selected by this medium. We improved the MCIC medium by supplementing with 1% adonitol. The new modified medium (MacConkey-inositol-adonitol-carbenicillin, MCIAC) had advantages over other selective Klebsiella media in having a higher selectivity and an incubation time of only 16,24 h. MCIAC could be routinely used for pathogenic Klebsiella selection of powdered milk and other food samples. [source]

SIDEROPHORE PRODUCTION, SERUM RESISTANCE, HEMOLYTIC ACTIVITY AND EXTENDED-SPECTRUM ,-LACTAMASE-PRODUCING KLEBSIELLA SPECIES ISOLATED FROM MILK AND MILK PRODUCTS

JOURNAL OF FOOD SAFETY, Issue 3 2007
HAN GUNDOGAN
ABSTRACT This study aimed at the isolation and identification of Klebsiella spp. from dairy product to establish their public health significance by determining their virulence factors, antibiotic resistance and extended-spectrum ,-lactamase (ESBL). Klebsiella pneumoniae, Klebsiella oxytoca and Klebsiella rhinoscleromatis were identified in 25 (58%), 11 (26%) and 7 (16%) isolates, respectively. A high prevalence of Klebsiella isolates had virulence factors such as siderophore production (63%), serum resistance (32.5%) and hemolytic activity (58%). ESBL - producing Klebsiella spp. was detected in 35% of the isolates. Resistance to the antimicrobial agents tested was found to be much higher in the ESBL-producing Klebsiella spp. than in non-ESBL-producing isolates. All ESBL-producing Klebsiella spp. showed high-level resistance to cephalosporins and monobactams. The majority of the serum resistant, siderophore, hemolysin and ESBL producers were K. pneumoniae. [source]

PROTECTIVE EFFECT OF LYSOSTAPHIN FROM STAPHYLOCOCCUS SIMULANS AGAINST GROWTH OF STAPHYLOCOCCUS AUREUS IN MILK AND SOME OTHER FOOD PRODUCTS

JOURNAL OF FOOD SAFETY, Issue 3 2007
PIOTR SZWEDA
ABSTRACT The effect of lysostaphin from Staphylococcus simulans expressed in Escherichia coli TOP10 strain on Staphylococcus aureus used for inoculation of milk, ground pork and mayonnaise salad was investigated. The populations of this pathogen in ultrahigh-temperature milk preserved at 4C by lysostaphin added up to concentrations of 1.5 or 3.0 µg/mL were reduced by 0.73 and 0.92 log(cfu/mL) in control samples without enzyme addition. The protective influence of lysostaphin was diminished in case of milk storage (20C) prolonged up to 24 h. Furthermore, a final reduction level by 0.92 log(cfu/mL) was achieved after 24 h of pork storage. The smaller and more dependent on enzyme concentration inactivation of S. aureus was observed in the case of the mayonnaise salad, and it led to the conclusion that some food components or proteolytic enzymes originating from other bacteria caused lysostaphin inactivation. [source]

SIMULTANEOUS RECOVERY AND DETECTION OF FOUR HEAT-INJURED FOODBORNE PATHOGENS IN GROUND BEEF AND MILK BY A FOUR-COMPARTMENT THIN AGAR LAYER PLATE

JOURNAL OF FOOD SAFETY, Issue 2 2006
VIVIAN C.H. WU
ABSTRACT A four-compartment thin agar layer (4-TAL) system was developed to improve operation efficiency and recover injured foodborne pathogens simultaneously. The system consisted of a layer of nonselective agar overlaid on four different selective agars (xylose lysine desoxycholate [XLD], cefsulodin irgasan novobiocin [CIN], modified Oxford medium [MOX] and MacConkey sorbitol agar [MSA]) housed in a four-compartment petri dish. We applied this system to simultaneously recover heat-injured (55C, 10 min) Escherichia coli O157:H7 (MSA), Listeria monocytogenes (MOX), Salmonella Typhimurium (XLD) and Yersinia enterocolitica (CIN) from ground beef and pasteurized milk. No significant difference (P > 0.05) occurred between the single recovery unit (nonselective agar overlaid on one selective agar in a standard petri dish) and the 4-TAL for detecting four heat-injured pathogens in tested samples. Both TAL methods showed greater recovery of four heat-injured pathogens than the pathogen-specific selective media (P < 0.05). The 4-TAL system appears to be efficient for recovery and detection of injured pathogens in food in terms of operation, material and labor costs, and space of incubation. [source]

SENSORY PROFILE OF FLAVOR AND ODOR CHARACTERISTICS IN RONCAL CHEESE MADE FROM RAW EWE'S MILK

JOURNAL OF SENSORY STUDIES, Issue 5 2002
PATRICIA LARRÁYOZ
ABSTRACT Roncal cheese is made from raw ovine milk and is regulated by an Appellation of Origin. This cheese variety is quite popular with consumers because of its special properties, which are unlike those of other ewe's-milk cheeses. To date there have been no studies aimed at characterizing the flavor and odor attributes of Roncal cheese. To remedy this situation, sensory analysis has been performed using Roncal cheese samples collected from artisanal and industrial cheese-making establishments. The cheeses were made at three different times of year (winter, spring, and summer) and were ripened for four or eight months. Sensory descriptors were generated, and after discussion suitable descriptors for describing and discriminating among Roncal cheese samples were selected by multivariate analysis. In all, 19 descriptors were employed, namely: odor: cream, meat broth, olive, toffee, liquid caramel, toasted, acetic acid, sweat, acidified milk, ammonia, leather, stable straw, wool, and odor intensity. flavor: characteristic flavor, acetic acid, sweat, butyric acid, and flavor intensity. [source]

RHEOLOGY OF DOUBLE (W/O/W) EMULSIONS PREPARED WITH SOYBEAN MILK AND FORTIFIED WITH CALCIUM

JOURNAL OF TEXTURE STUDIES, Issue 5 2010
ANDRÉS L. MÁRQUEZ
ABSTRACT The objective of this work was to study the rheological behavior of water-in-oil-in-water (w/o/w) emulsions prepared with soybean milk and sunflower oil, with different calcium solutions as the internal aqueous phase, in order to evaluate them as a vegetable substitute of whipped dairy cream. The obtained systems exhibited a creamy texture, which was attributed to the swelling of w/o droplets because of the osmotic gradient generated by the inclusion of soluble salts in the internal aqueous phase. A secondary factor could be the flocculation of w/o droplets due to the interaction of released calcium with soybean proteins at the interface. Consequently, the increase of calcium chloride content produced emulsions with higher consistency. A pasteurization produced flocculation and coalescence of w/o droplets only at high calcium chloride content. These double emulsions could be a potential alternative to the whipped dairy cream, because of their texture, reduced fat content and calcium contribution. PRACTICAL APPLICATIONS This article deals with the formulation of novel calcium-fortified food emulsions prepared with soybean milk and sunflower oil. Because calcium needs to be isolated from soybean milk components (proteins and phospholipids), we proposed to include calcium salts in the internal aqueous phase of a water-in-oil-in-water (w/o/w) emulsion. The practical applications of this research could include the formulation of low lipid content emulsions and the isolation of a component which is incompatible with the continuous aqueous phase. Particularly, this work leads to the understanding of how the inclusion of calcium salts in the internal aqueous phase of a w/o/w emulsion prepared with soybean milk affects the rheology and microstructure of the system. The results led to the conclusion that these emulsions can work as a whipped dairy cream substitute with vegetal components, low lipid content and important calcium contribution. [source]

MICROSTRUCTURAL AND RHEOLOGICAL PROPERTIES OF LOW-FAT STIRRED YOGHURTS MADE WITH SKIM MILK AND MULTIPLE EMULSIONS

JOURNAL OF TEXTURE STUDIES, Issue 6 2009
C. LOBATO-CALLEROS
ABSTRACT This article focuses on the study of the dynamic rheological and structural properties developed in low-fat stirred yoghurts made with skim milk and multiple emulsions stabilized with carboxymethylcellulose (SYCMC) or amidated low methoxy pectin (SYALMP), in comparison with a full milk-fat stirred yoghurt control (SYMF). The SYALMP yoghurt exhibited greatest Tan,after 14 days of storage than the SYMF and SYCMC yoghurts. The SYALMP yoghurt presented the highest lacunarity value and was characterized by a structure composed of highly clusterized casein aggregates. In contrast, the SYCMC and SYMF yoghurts displayed lower lacunarity values and structures characterized by smaller casein clusters. Lower Tan,values were associated with lower lacunarity values. PRACTICAL APPLICATIONS Limited work has been done on stirred and set-style yoghurts, cheeses and, in general, dairy products, where milk-fat globules are substituted by skim milk combined with multiple emulsions containing polyunsaturated vegetable oils. As a result of this, multicomponent gels formation occurs (made up by milk proteins, polyunsaturated vegetable oils, emulsifiers, hydrocolloids and many possible other ingredients), which give rise to completely different structural arrangements that may display comparable mechanical-sensory properties with those exhibited by their full milk-fat counterparts, paving the way for the development of new healthier foods sensory and texturally acceptable to consumers. [source]

EFFECT OF COLD STORAGE ON CULTURE VIABILITY AND SOME RHEOLOGICAL PROPERTIES OF FERMENTED MILK PREPARED WITH YOGURT AND PROBIOTIC BACTERIA

JOURNAL OF TEXTURE STUDIES, Issue 1 2008
MARIA REGINA DAMIN
ABSTRACT We examined the effect of storage time on culture viability and some rheological properties (yield stress, storage modulus, loss modulus, linear viscoelastic region, structural recuperation and firmness) of fermented milk made with Lactobacillus delbrueckii ssp. bulgaricus, Lactobacillus acidophilus (LA) and Bifidobacterium animalis ssp. lactis in coculture with Streptococcus thermophilus (ST). Acidification profiles and factors that affect viability (postfermentation acidification, acidity and dissolved oxygen) were also studied during 35 days at 4C. Fermented milk prepared with a coculture of ST and Bifidobacterium lactis gave the most constant rheological behavior and the best cell viability during cold storage; it was superior to ST plus LA for probiotic fermented milk production. PRACTICAL APPLICATIONS Probiotic cultures should grow quickly in milk, provide adequate sensory and rheological properties to the product, and remain viable during storage. Commercially, it is very common to use yogurt starter culture (i.e. Streptococcus thermophilus[ST] and Lactobacillus delbrueckii ssp. bulgaricus) in combination with the probiotic bacteria in order to reduce fermentation time. However, LB tends to post acidify fermented milk, which reduces the viability of the probiotic bacteria; thus, it is recommended to use starter cultures devoid of this species. We found that the technological properties and the viability of the probiotic bacterium Bifidobacterium animalis ssp. lactis BL O4 in coculture with ST make it suitable for probiotic fermented milk production; it produces rheological characteristics similar to those of yogurt. [source]

EFFECT OF MANGO PULP AND SOYMILK FORTIFICATION ON THE TEXTURE PROFILE OF SET YOGHURT MADE FROM BUFFALO MILK

JOURNAL OF TEXTURE STUDIES, Issue 3 2003
PRADYUMAN KUMAR
The effect of the fat content in buffalo milk and proportions of buffalo milk, soymilk and mango pulp on textural characteristics of mango soy fortified yoghurt (MSFY) is reported. The TA-XT2 Texture Analyzer was used to measure the textural characteristics of MSFY prepared from blends containing varying proportions of buffalo milk (varying fat content), soymilk (8.2% total solids) and mango pulp (18% total solids). Texture profile data were used to develop regression models for dependent variables,hardness (HD), cohesiveness (CO), adhesiveness (AD), springiness (SP) and gumminess (GU), which were used to optimize the blend formula. The optimized values are 2.95% fat content in buffalo milk, 14.7% soymilk and 7.2% mango pulp in the blend for obtaining MSFY having textural characteristics similar to those of yoghurt having 6% fat. The MSFY prepared using optimized blend had HD (108 - 112 g), CO (0.41 - 0.42), AD (- 70.3 to - 72.9 g.s), SP (0.93 - 0.96) and GU (45.05 - 46.38 g). [source]

INSTRUMENTAL TEXTURE OF SET AND STIRRED FERMENTED MILK.

JOURNAL OF TEXTURE STUDIES, Issue 3 2001
EFFECT OF A ROPY STRAIN OF LACTOBACILLUS DELBRUECKII SUBSP.
Texture profile analysis (TPA) of stirred and set cultured milk were evaluated, using an exopolysaccharide producing strain of Lactobacillus delbrueckii subsp. bulgaricus (NCFB 2772) and a protein enriched substrate (retentate). In both cases, samples were compared respectively with a nonropy strain (NCFB 1489) and reconstituted skim milk substrate. The retentate fermented products were firmer in comparison with skim milk products, both at 10% of total solids. A loss of structure occurred when the retentate products were stirred causing a nine-fold decrease in hardness, whereas in cultured milk products the loss was of around three-fold. The main differences were found in adhesiveness and fracture characteristics. Set retentate ropy product was five times more adhesive than the nonropy one, whereas in stirred retentate and set skim milk products the difference was two-fold. No differences in adhesiveness were detected when skim milk products were stirred using either strain. The fracture force on ropy retentate samples increased after fracture while the nonropy ones showed a decrease, implying more structural breakdown in the latter. On set products, cohesiveness increased slightly due to the ropy strain. Changes in texture observed between ropy and nonropy strains can be attributed to exopolysaccharide attachment to the casein matrix being increased when the protein content is higher. [source]

SENSORY AND INSTRUMENTAL EVALUATIONS OF TEXTURE IN CHEESES MADE FROM OVINE MILKS WITH DIFFERING FAT CONTENTS

JOURNAL OF SENSORY STUDIES, Issue 2 2002
A. IRIGOYEN
ABSTRACT The present study considers the influence of reducing the fat content of ovine milk on the sensory and instrumental texture characteristics of the resulting cheeses. Three manufacturing runs were performed. In each run three cheese batches were manufactured using milks with differing percentage fat contents (8%, 4%, and 2% fat). Analysis of cheese samples was performed at 60, 90, and 120 days of ripening. The instrumental method used to evaluate cheese texture was uniaxial compression at constant speed, taking readings of stress, strain, and modulus of elasticity (E). Statisticalanalysis revealed differences forboth the differentfat contents and the ripening times considered. Instrumental parameter values increased with lower cheese fat contents; with a 20% reduction in the fat to dry matter content from full-fat to reduced-fat cheeses, resulting in a 35% increase in maximum stress and in the slope of the stress-strain curve at the end of ripening. The greatest sensory differences between samples were recorded for firmness. [source]

Evolution of a novel function: nutritive milk in the viviparous cockroach, Diploptera punctata

EVOLUTION AND DEVELOPMENT, Issue 2 2004
Anna Williford
Summary Cockroach species show different degrees of maternal contribution to the developing offspring. In this study, we identify a multigene family that encodes water-soluble proteins that are a major component of nutritive "Milk" in the cockroach, Diploptera punctata. This gene family is associated with the evolution of a new trait, viviparity, in which the offspring receive nutrition during the gestation period. Twenty-five distinct Milk complementary DNAs were cloned and partially characterized. These complementary DNAs encode 22 distinct Milk peptides, each of length 171 amino acids, including a 16-amino acid signal peptide sequence. Southern blot analysis confirms the presence of multiple copies of Milk genes in D. punctata. Northern analysis indicates tissue- and stage-specific Milk gene expression. Examination of the deduced amino acid sequences identifies the presence of structurally conserved regions diagnostic of the lipocalin protein family. The shared exon/intron structure of one of the Milk loci with lipocalin genes further supports a close evolutionary relationship between these sequences. [source]

Milk,Alkali syndrome: broadening the spectrum of causes to allow early recognition

INTERNAL MEDICINE JOURNAL, Issue 6 2004
T. J. Kleinig
No abstract is available for this article. [source]

Interlaboratory Collaborative Studies on Reference Method ISO 1211/IDF 1 for the Determination of Fat Content in Cow Milk, Sheep Milk and Goat Milk

INTERNATIONAL JOURNAL OF DAIRY TECHNOLOGY, Issue 3 2010
Anna Polychroniadou
No abstract is available for this article. [source]

Interlaboratory Collaborative Study on the Kjeldahl Reference Method for Nitrogen Determination in Sheep and Goat Milk according to ISO 8968-1/2,IDF 20-1/2

INTERNATIONAL JOURNAL OF DAIRY TECHNOLOGY, Issue 3 2010
Anna Polychroniadou
No abstract is available for this article. [source]

Probiotic fermented milks: Present and future

INTERNATIONAL JOURNAL OF DAIRY TECHNOLOGY, Issue 4 2009
BORJA SÁNCHEZ
Milk and dairy products have been part of human nutrition since ancient times, constituting an important part of a balanced diet. Fermented dairy products containing living micro-organisms have traditionally been used to restore gut health, being among the pioneers in functional foods. Such utilisation of live micro-organisms forms the basis of the probiotic concept, which constitutes a fast growing market for the development of new products. In this article, we review the current status of fermented milk as a vehicle for delivery of beneficial bacteria and look into future new directions and challenges. [source]

Fat and protein contents, acidity and somatic cell counts in bulk milk of Holstein cows in the Khorasan Razavi Province, Iran

INTERNATIONAL JOURNAL OF DAIRY TECHNOLOGY, Issue 1 2009
MASOUD NAJAF NAJAFI
Relationships between total bulk milk somatic cell score (SCS) and milk fat and protein contents and acidity were investigated in the Khorasan Razavi Province, a region that contributes 6.83% of total milk production in Iran. A total of 1476 samples were analysed. Data were obtained by randomly collecting 123 samples of bulk tank milk from 41 dairy farms during April 2006 to March 2007, every month. Milk was analysed for titratable acidity, protein and fat contents and somatic cell counts (direct microscopic cell count and with Somatos, Russia). Microscopic and Somatos somatic cell counts were comparable. Results showed that the season of raw milk production did not have a significant effect on acidity. Milk fat content increased gradually from spring to winter and there were significant differences (P < 0.05) between spring and other seasons. Higher levels of milk protein fractions were observed during the autumn and winter than in other seasons. The highest total bulk milk somatic cell counts were observed in July. Total bulk milk SCS had significant effects (P < 0.05) on acidity and fat and protein contents. Moreover, the level of acidity and fat in milk decreased with increasing SCS. A significant positive relationship was observed between total bulk milk SCS and the protein content of milk. Elevated SCS were associated with lowered milk quality in Holsteins in the Khorasan Razavi Province. [source]

Payment Systems for Ex-farm Milk

INTERNATIONAL JOURNAL OF DAIRY TECHNOLOGY, Issue 3 2007
John Sumner
No abstract is available for this article. [source]

Food process engineering and dairy technology at the Technical University of Munich

INTERNATIONAL JOURNAL OF DAIRY TECHNOLOGY, Issue 4 2003
Ulrich Kulozik
The Chair for Food Process Engineering and Dairy Technology at the Technical University of Munich in Freising-Weihenstephan has been installed since 1992 in a new building hosting modern and well-equipped laboratories and pilot-plant facilities. Its objectives in terms of research are to participate in the development of the scientific understanding of complex food systems and their constitutive components, and the way they interact with the process during manufacturing. The aim is to allow the production of food products with desired properties, improved quality and optimal safety, while ensuring an efficient use of raw materials and of the energy required for industrial production. The methodology used involves the fractionation of complex systems and the systematic study of their constitutive components taken in isolation as well as in various combinations. Milk, as a naturally complex raw material, receives particular attention, but research activities increasingly extend to other functional food substrates such as eggs. The research activities are organized into three working groups that reflect the core competencies developed at the chair throughout the years: Bio-Processes and Aseptic Processing, Formation of Structures in Food Systems, and Protein Technology. Its key position within the ,Centre of Life and Food Science' of the Technical University of Munich fosters interdisciplinary interactions with many specialized scientists, and therefore provides a broad perspective regarding the comprehension of the complex implications of modern food and pharmaceutical product manufacturing. [source]

Clinical and Economic Outcomes of Infants Receiving Breast Milk in the NICU

JOURNAL FOR SPECIALISTS IN PEDIATRIC NURSING, Issue 1 2001
Amy J. Barton
ISSUES AND PURPOSE. This study compared clinical and economic outcomes for infants who were exclusively fed breast milk and infants who were fed commercial formula. DESIGN AND METHODS. A retrospective medical record review from a regional neonatal intensive care unit (N = 80) using consultation logs from the lactation coordinator and a matched sample of formula-fed infants. RESULTS. Neither clinical (weight gain, length of stay, days of parenteral nutrition) nor economic outcomes (direct variable costs, net revenue) differed significantly between the groups. PRACTICE IMPLICATIONS. While it may not be possible to demonstrate sufficient cost savings while the infant resides within the NICU to justify a lactation coordinator, long-term clinical and economic outcomes may be sensitive to this specialized nursing service. [source]

Application of robust procedures for estimation of breeding values in multiple-trait random regression test-day model

JOURNAL OF ANIMAL BREEDING AND GENETICS, Issue 1 2007
J. Jamrozik
Summary Robust procedures for estimation of breeding values were applied to multiple-trait random regression test-day (TD) model to reduce the influence of outliers on inferences. Robust estimation methods consisted of correcting selected observations (defined as outliers) in the process of solving mixed-model equations in such a way that ,new' observations gave residuals (actual observation minus predicted) within k residual standard deviations for a given day in milk in 305-day lactation. Data were 980 503 TD records on 63 346 Canadian Jersey cows. Milk, fat, protein and somatic cell score in the first three lactations were analysed jointly in the model that included fixed herd-TD effect and regressions within region,age,season of calving, and regressions with random coefficients for animal genetic and permanent environmental effects. All regressions were orthogonal polynomials of order 4. Robust procedures for k = 1.5, 2.0, 2.5, 2.75 and 3.0 were contrasted with the regular best linear unbiased prediction (BLUP) method in terms of numbers and distributions of outliers, and estimated breeding values (EBV) of animals. Distributions of outliers were similar across traits and lactations. Early days in milk (from 5 to 15) were associated with larger frequency of outliers compared with the remaining part of lactation. Several, computationally simple, robust methods (for k > 2.0) reduced the influence of outlier observations in the model and improved the overall model performance. Differences in rankings of animals from robust evaluations were small compared with the regular BLUP method. No clear associations between changes in EBV (rankings) of top animals from different methods and the occurrence of outliers were detected. [source]

Metabolic and luteal function in winter-calving Spanish beef cows as affected by calf management and breed

JOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 3 2010
J. Álvarez-Rodríguez
Summary This experiment aimed at evaluating the effect of calf management and breed on the metabolic and luteal function of post-partum beef cows fed at maintenance. Fifty multiparous cows, 22 Parda de Montaña (PA) and 28 Pirenaica (PI), were assigned to either suckling once-daily for 30 min (RESTR) or ad libitum (ADLIB) from the day after calving. Blood samples were collected to analyse metabolites [non-esterified fatty acids (NEFA), ,-hydroxybutyrate, total protein and urea)], insulin-like growth factor-I (IGF-I) and progesterone (P4) at different intervals. Cows from RESTR maintained their live-weight (LW) over the first 3 months post-partum, whereas ADLIB cows lost nearly 4% LW. Both genotypes showed similar LW gains during this period (p > 0.10). Calf daily gains were lower in RESTR than in ADLIB treatment (p < 0.05), but similar across breeds (p > 0.10). Milk and lactose production were lower in RESTR cows than in ADLIB (p < 0.05). Milk and protein yield were greater in PA than in PI breed (p < 0.05). Serum NEFA, total protein and urea were higher in PI cows suckling ADLIB than in the rest (p < 0.05). Cows from PI breed had greater NEFA values than PA ones on the first week post-partum (p < 0.001). Circulating IGF-I was not affected by suckling frequency, breed nor their interaction (p > 0.10). Suckling frequency, but not breed, affected the interval from calving to first ovulation (p < 0.001), being shorter in RESTR than in ADLIB cows. In conclusion, the ad libitum suckling practice improved cow milk yield and offspring gain compared to once-daily suckling for 30 min from the day after calving, at the expense of impairing the onset of cyclicity. The effect of calf management was confounded with breed on the studied blood biochemical constituents, but any of these metabolites influenced the role of endocrine IGF-I in these genotypes. [source]