Journal of Dairy Research (J Dairy Res )

Publisher: Cambridge University Press, Cambridge University Press

Description

Published for the Institute of Food Research and the Hannah Research Institute Journal of Dairy Research publishes original scientific research and reviews on all aspects of dairy science including: animal husbandry; the physiology biochemistry and endocrinology of lactation; milk production composition preservation processing and separation; biotechnology and food science; properties of milk proteins and other components; dairy products such as cheese fermented milks and spreads; relevant studies in bacteriology enzymology and immunology the use of milk products in other foods; and the development of methods relevant to these subjects.

  • Impact factor
    1.34
  • 5-year impact
    0.00
  • Cited half-life
    0.00
  • Immediacy index
    0.27
  • Eigenfactor
    0.00
  • Article influence
    0.48
  • Website
    Journal of Dairy Research website
  • Other titles
    Journal of dairy research (Online)
  • ISSN
    1469-7629
  • OCLC
    41884076
  • Material type
    Document, Periodical, Internet resource
  • Document type
    Internet Resource, Computer File, Journal / Magazine / Newspaper

Publisher details

Cambridge University Press

  • Pre-print
    • Author can archive a pre-print version
  • Post-print
    • Author can archive a post-print version
  • Conditions
    • Author's Pre-print on author's personal website, departmental website, social media websites, institutional repository, non-commercial subject-based repositories, such as PubMed Central, Europe PMC or arXiv
    • Author's post-print for HSS journals, on author's personal website, departmental website, institutional repository, non-commercial subject-based repositories, such as PubMed Central, Europe PMC or arXiv, on acceptance of publication
    • Author's post-print for STM journals, on author's personal website on acceptance of publication
    • Author's post-print for STM journals, on departmental website, institutional repository, non-commercial subject-based repositories, such as PubMed Central, Europe PMC or arXiv, after a 6 months embargo
    • Publisher's version/PDF cannot be used
    • Published abstract may be deposited
    • Pre-print to record acceptance for publication
    • Publisher copyright and source must be acknowledged with set statement, for deposit of Authors Post-print or Publisher's version/PDF
    • Must link to publisher version
    • Publisher last reviewed on 07/10/2014
  • Classification
    ​ green

Publications in this journal

  • [Show abstract] [Hide abstract]
    ABSTRACT: The heat-induced changes in pH, Ca activity and viscosity after heating at 90 °C for 10 min of five modified skim milks were studied as a function of the initial pH of the milks at 25 °C. The milks had (i) different ratios of casein : whey protein (0·03, 1·74, 3·97, 5·27 and 7·25), (ii) the same total solids concentration (9% w/w) and (iii) prior to the adjustment of the pH, similar values of pH (6·67-6·74), concentration of serum calcium, and calcium activity, suggesting that the sera have similar mineral composition. The total protein concentrations of the milks differ (2·8-4·0%, w/w). The pH decrease in situ upon heating from 25-90 °C was similar for all the modified skim milks with the same starting pH, suggesting that the pH changes to milk on heating were primarily mediated by the initial mineral composition of the serum and were unaffected by the casein : whey protein ratio or the total protein content of the milk. The heat-induced changes in pH and calcium activity were largely reversible on cooling. The two milks with the lowest ratios of casein to whey protein gelled on heating to 90 °C for 10 min and cooling to 25 °C when the pH was adjusted to pH = 6·2 prior to heating. The viscosities of all other milks with casein to whey protein ratio of 3·97, 5·27 and 7·25 and/or pH ≥6·7 prior to heating did not change significantly. The effect of casein : whey protein ratio and the pH are the dominant factors in controlling the susceptibility to thickening of the milks on heating in this study.
    Journal of Dairy Research 12/2014;
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    ABSTRACT: Three-year cohort study was carried out to investigate the influence of small ruminant lentivirus (SRLV) infection on cheese yield in goats. For this purpose records of milk yield, milk composition and cheese yield were collected in a dairy goat herd. Cheese yield was recorded as the amount of fresh cheese obtained from 1 kg milk. All goats were serologically tested for SRLV infection twice a year. The analysis included 247 records in total (71 for seropositive and 176 from seronegative individuals) and was carried out with the use of the four-level hierarchical linear model (α = 0·05). SRLV infection proved to be a statistically significant independent factor reducing cheese yield (P = 0·013) - when other covariates were held constant cheese yield was reduced by 4·6 g per each 1 kg milk in an infected goat compared with an uninfected goat. Other statistically significant covariates positively associated with cheese yield were protein contents, fat contents and the 3rd stage of lactation (P < 0·001 for all).
    Journal of Dairy Research 12/2014;
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    ABSTRACT: Often the only way to ensure profitability of Lacaune dairy sheep is intensive management, which requires appropriate dry-period treatment to ensure animal productivity and health. The present study aimed to investigate the effects of intramammary antibiotic dry therapy on the performance and health of Lacaune sheep under intensive management. We recorded data for 5981 complete lactation periods that followed a dry period. A total of 2402 lactation periods were preceded by a dry period involving intramammary administration of 300 mg of cephapirin benzathine (antibiotic group) and 3579 lactation periods were preceded by dry periods with no treatment (control group). The following on-farm yield data were collected for individual lactation periods: length of the subsequent lactation period; total milk yield per lactation period; daily milk yield and length of the subsequent dry period. Data on confounding factors that might affect productivity were also recorded, including the individual ewe, number of lactation periods and length of the previous dry period. Milk quality was assessed using data on somatic cell count (SCC) and content of protein and fat taken from the Spanish National Official Milk Yield Recording System. Antibiotic dry therapy significantly improved total yield per lactation period, which was 429±151·1 l in the antibiotic group and 412±165·5 l in the control group, as well as the daily milk yield, which was 1986±497·0 and 1851±543·2 ml/d, respectively (both P<0·0001). The initial dry period was significantly longer in the antibiotic group than in the control group, and dry period length correlated inversely with yield variables such us total yield per lactation period (r=-0·055; P<0·0001) and yield per day in milk (r=-0·039; P<0·0001). As a result, milk yield records systematically underestimated the positive effects of antibiotic dry therapy. Antibiotic dry therapy also significantly improved milk quality. Milk from the antibiotic group showed 50% lower SCC (573±1326 vs. 1022±2126 cells/ml; P<0·0001) and slightly higher content in fat (7·33±0·91 vs. 7·15±0·87%) and protein (5·63±0·44 vs. 5·44±0·4%). The results of this study suggest that cephalosporin dry therapy of Lacaune dairy sheep increases milk production and improves milk quality during subsequent lactation periods.
    Journal of Dairy Research 12/2014;
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    ABSTRACT: In both conventional and automatic milking systems (AMS), sensitive and reliable mastitis detection is important for profitable milk production. Mastitis detection parameters must be able to detect mastitis when the somatic cell count (SCC) is only slightly elevated. Owing to the pre-milking teat cleaning process in AMS, sampling cannot take place before the occurrence of alveolar milk ejection and importantly, this can affect the ability of parameters to detect mastitis. The aim of the present study was to examine the effect of alveolar milk ejection on l-lactate, lactate dehydrogenase (LDH), serum albumin (SA) and immunoglobulin G (IgG) compared with SCC, a commonly used indicator of mastitis. In this experiment, milk samples were collected every 20 s from one quarter during a 120-s manual teat stimulation in ten cows. Samples were analysed for SCC, l-lactate, LDH, SA and IgG. Quarters were grouped by low (<5·0 log10 cells/ml), mid (5·0-5·7 log10 cells/ml), and high (>5·7 log10 cells/ml) SCC using the sample at t=0 s. Neither l-lactate nor LDH could statistically differentiate between low and mid-SCC quarters, but there were a significant difference in levels between the high-SCC quarters and low and mid-SCC quarters. SA could not differentiate between the low and mid-SCC quarters, but the SA levels for the high SCC quarters remained statistically different compared with low and mid-SCC quarters throughout the experiment. IgG could statistically differentiate between low and mid-SCC, although the high-SCC quarters were not statistically different from the mid-SCC quarters after 60 s. In the high-SCC quarters, a decrease was shown in all parameters during milk ejection, after t=60 s. In conclusion, alveolar milk ejection reduces the effectiveness of detection parameters when compared with SCC. With the exception of IgG, the ability of other tested parameters was not satisfactory to differentiate between quarters with low to mid-SCC levels.
    Journal of Dairy Research 12/2014;
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    ABSTRACT: Very little is known about the udder characteristics, partitioning of milk in the mammary gland and efficiency of machine milking in donkeys. This study aimed to evaluate the characteristics of the udder and teats, milk yield in relation to pulsation rates (90, 120 and 150 cycles/min), milk partitioning in the mammary gland, composition of the spontaneously removed and residual milk fractions and milking efficiency. Forty-one healthy Martina Franca jennies in the third month of lactation and routinely milked twice daily were used in three studies. Udder characteristics were evaluated by direct measurements and ultrasonographic scanning. Residual milk was obtained by milking after an oxytocin administration (40 IU i.m.). The prevalent shapes were 'bowl' for udders and 'conical' for teats. After milking the udder characteristics decreased within a range from -11·6% (udder depth) to -25·7% (diameter of teat at the base). The internal structures of the udder resulted as several pockets of ducts empting directly into the teat. The pulsation rate of 120 cycles/min improved (P<0·05) the milk yield in comparison to the 90 and 150 cycles/min, reduced the residual milk fraction, thus improved (P<0·05) milking efficiency. Residual milk composition had higher (P<0·05) fat content and somatic cell count than the spontaneously removed milk fraction. The udders revealed several pockets of ducts empting into the teat instead of a single cisternal cavity and showed a certain compliance. The use of 120 cycles/min pulsation rate improved milking efficiency.
    Journal of Dairy Research 12/2014;
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    ABSTRACT: Milk fatty acid (FA) synthesis by the mammary gland involves expression of a large number of genes whose nutritional regulation remains poorly defined. In this study, we examined the effect of long-term under- and over-feeding on the expression of genes (acetyl Co A carboxylase, ACC; fatty acid synthetase, FAS; lipoprotein lipase, LPL; stearoyl Co A desaturase, SCD; peroxisome proliferator activated receptor γ2, PPARγ2; sterol regulatory element binding protein-1, SREBP-1c; and hormone sensitive lipase, HSL) related to FA metabolism in sheep mammary tissue (MT). Twenty-four lactating sheep were divided into three homogenous sub-groups and fed the same ration in quantities covering 70% (underfeeding), 100% (control) and 130% (overfeeding) of their energy and crude protein requirements. The results showed a significant reduction of mRNA of ACC, FAS, LPL and SCD in the MT of underfed sheep, and a significant increase on the mRNA of LPL and SREBP-1c in the MT of overfed compared with the control respectively. In conclusion, the negative, compared to positive, energy balance in sheep down-regulates ACC, FAS, LPL, SCD, SREBP-1c and PPARγ2 expression in their MT which indicates that the decrease in nutrient availability may lead to lower rates of lipid synthesis.
    Journal of Dairy Research 12/2014;
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    ABSTRACT: The aim of the current study was to asses the effect of goat or cow milk-based diets, either normal or Fe-overloaded and folic acid supplement on some aspects of hepatic physiology, enzymatic antioxidant defence and lipid peroxidation in liver, brain and erythrocyte of control and anaemic rats after chronic Fe repletion. 160 male Wistar rats were placed on 40 d in two groups, a control group receiving normal-Fe diet and the Fe-deficient group receiving low Fe diet. Lately, the rats were fed with goat and cow milk-based diets during 30 d, with normal-Fe content or Fe-overload and either with normal folic or folic acid supplemented. Fe-overload increased plasma alanine transaminase and aspartate transaminase levels when cow milk was supplied. Dietary folate supplementation reduced plasma transaminases levels in animals fed goat milk with chronic Fe overload. A remarkable increase in the superoxide dismutase activity was observed in the animals fed cow milk. Dietary folate supplement lead to a decrease on the activity of this enzyme in all the tissues studied with both milk-based diets. A concomitant increment in catalase was also observed. The increase in lipid peroxidation products levels in rats fed cow milk with Fe-overload, suggest an imbalance in the functioning of the enzymatic antioxidant defence. In conclusion, dietary folate-supplemented goat milk reduces both plasma transaminases levels, suggesting a hepatoprotective effect and has beneficial effects in situation of Fe-overload, improving the antioxidant enzymes activities and reducing lipid peroxidation.
    Journal of Dairy Research 11/2014;
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    ABSTRACT: The similarity of mare's milk to breast milk makes it an interesting substrate for the creation of dairy beverages. The aim of this study was to determine the immunoreactivity of the digested mare's milk products carried out by lactic acid fermentation with Lactobacillus casei LCY, Streptococcus thermophilus MK10 and Bifidobacterium animalis Bi30. Simulation of digestion with saliva, pepsin and pancreatin/bile salts was carried out. The immunoreactivity of the milk proteins was assessed by competitive ELISA. The separation of proteins was studied using a tricine SDS-PAGE method. It has been demonstrated that lactic acid fermentation significantly decreases the immunoreactivity of β-lactoglobulin, β-casein, κ-casein and bovine serum albumin. The level of reduction was connected to the type of bacterial strain. The simulated digestion processes caused the decline of immunoreactivity, and the decreases obtained in the experiment were as follows: lactoferrin: 95%, β-lactoglobulin: 94%, β-casein: 93%, α-lactalbumin: 82%, α-casein: 82%, bovine serum albumin: 76% and κ-casein: 37%. The results of the study indicated that microbial fermentation with tested strains is a valuable method for reducing the immunoreactivity of mare's milk proteins. However, further studies with other bacterial strains are needed to gain a higher level of elimination or total reduction of mare's milk immunoreactivity to possibly introduce fermented mare's milk into the diet of patients with immune-mediated digestive problems.
    Journal of Dairy Research 11/2014;
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    ABSTRACT: This study was conducted to assess the effect of prebiotic galactooligosaccharides (GOS) on alloxan-induced diabetes in male Sprague-Dawley (SD) rats. Diabetes was induced by administration of alloxan (100 mg/kg) and rats were divided in 4 groups: normal control group (NCG), prebiotic control group (PCG), diabetic control group (DCG) and diabetic prebiotic group (DPG). While PCG and DPG were fed with GOS supplemented (10% w/w) diet, NCG and DCG were administered with basal diet. Rats were sacrificed after 42 d for collection of blood and liver. Faecal samples were collected at the interval of 7 d throughout the study for measurement of lactobacilli and coliform count. Feeding of GOS decreased or delayed the severity of diabetes by amelioration of diabetes associated markers including fasting blood glucose, haemoglobin, glycosylated haemoglobin triglycerides, total cholesterol, low density lipoproteins, creatinine and urea. GOS was also found to improve the levels of antioxidative enzymes (superoxide dismutase, catalase and glutathione peroxidase) in liver and blood. Improvement in lactobacilli count along with a concomitant decrease in coliform count was observed in GOS fed groups.
    Journal of Dairy Research 11/2014;
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    ABSTRACT: This study developed mathematical models in order to evaluate the effect of A w (Water activity) and growth temperature on Staphylococcus aureus kinetic behaviour. The A w levels (0·970, 0·975, 0·983, and 0·991) of cheese were adjusted by NaCl; then, Staph. aureus was inoculated on the cheese, followed by storage at 7-30 °C for 72-720 h. Total bacterial and Staph. aureus cell counts were enumerated on tryptic soy agar and mannitol salt agar, respectively. The Baranyi model was fitted to the Staph. aureus growth data in order to calculate the maximum specific growth rate (μmax; log CFU/g/h), lag phase duration (λ; h), lower asymptote (N 0; log CFU/g) and upper asymptote (N max; log CFU/g). The effects of storage temperature and A w on the kinetic parameters (μmax and λ) were then further analysed with the Ratkowsky-type model and a polynomial equation, respectively. The root mean square error (RMSE) and relative error (RE) were calculated in order to estimate the model performance. No significant effect of A w on Staph. aureus growth was observed at 7 °C; thus, the Baranyi model was fitted to the growth data from 15, 25 and 30 °C. The μmax values (0·011-0·303 log CFU/g/h) increased (P<0·05) as the storage temperature and A w increased. In addition, λ values (2·42-63·48 h) decreased (P<0·05) as storage temperature and A w increased; yet, the effect of A w on λ was observed only at 15 °C. The theoretical minimum storage temperature and A w were 10·15 °C and 0·882, respectively. RMSE (0·010-1·544) and RE values (-0·131 to 0·187) from validation indicated that model performance was appropriate. Hence, these results suggest that the developed models in this study should be useful in describing the effect of temperature and A w on the growth kinetic behaviour of Staph. aureus in cheese along with the exposure assessment of Staph. aureus in cheese as well.
    Journal of Dairy Research 11/2014;
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    ABSTRACT: We recently reported the identification of a peptide from yoghurts with promising potential for intestinal health: the sequence (94-123) of bovine β-casein. This peptide, composed of 30 amino acid residues, maintains intestinal homoeostasis through production of the secreted mucin MUC2 and of the transmembrane-associated mucin MUC4. Our study aimed to search for the minimal sequence responsible for the biological activity of β-CN(94-123) by using several strategies based on (i) known bioactive peptides encrypted in β-CN(94-123), (ii) in silico prediction of peptides reactivity and (iii) digestion of β-CN(94-123) by enzymes of intestinal brush border membranes. The revealed sequences were tested in vitro on human intestinal mucus-producing HT29-MTX cells. We demonstrated that β-CN(108-113) (an ACE-inhibitory peptide) and β-CN(114-119) (an opioid peptide named neocasomorphin-6) up-regulated MUC4 expression whereas levels of the secreted mucins MUC2 and MUC5AC remained unchanged. The digestion of β-CN(94-123) by intestinal enzymes showed that the peptides β-CN(94-108) and β-CN(117-123) were present throughout 1·5 to 3 h of digestion, respectively. These two peptides raised MUC5AC expression while β-CN(117-123) also induced a decrease in the level of MUC2 mRNA and protein. In addition, this inhibitory effect was reproduced in airway epithelial cells. In conclusion, β-CN(94-123) is a multifunctional molecule but only the sequence of 30 amino acids has a stimulating effect on the production of MUC2, a crucial factor of intestinal protection.
    Journal of Dairy Research 10/2014;
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    ABSTRACT: Active films were developed for food coating applications. Entrapped phenol susceptibility to digestion was studied. Sodium caseinate (Na-CN) coatings were formulated with 0, 10, 20% Casein (CN) incorporating selected phenols as model antioxidants. This study investigated phenol/CN/Na-CN interactions, in vitro bioaccessibility of phenols and CN role in phenols retention during in vitro gastric and pancreatic digestion. The antioxidant activity of catechin (CAT), rutin (RUT), chlorogenic acid (CHL), gallic acid (GAL), and tannic acid (TA) in coatings varied with the phenolic compound type and CN concentration and was related to phenol hydrophobic binding to CN. ABTS method gave activities ranged from 412 down to 213, and DPPH method gave values from 291·7 to 190·9. An inverse relationship was found with CN content due to CN/phenol interaction. During digestion, a part of phenols was degraded by alkaline pH of pancreatic fluid. Simultaneously, CN proteolysis led to release of phenols and the bioaccessibility index remained above 80% for all phenols. The results suggested the possibility of protecting phenols against oxidation and digestive alteration by entrapment in CN and Na-CN coating films. These positive results showed the ability to produce antioxidant-enriched edible coatings to increase food protection and phenol nutritional intake.
    Journal of Dairy Research 10/2014;
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    ABSTRACT: The relationship between hydrophobicity and the protective effect of whey protein hydrolysates (WPHs) against oxidative stress was studied. Whey protein was first hydrolysed by pepsin and trypsin to obtain WPHs. After absorbed by macroporous adsorption resin DA201-C, three fractions named as M20, M40, and M60 were eluted by various concentrations of ethanol. The hydrophobicity showed a trend of increase from M20 to M60. Antioxidant ability test in vitro indicated that all the three components of WPHs displayed reasonably good antioxidant ability. Moreover, with the increase of hydrophobicity, antioxidant ability of WPHs improved significantly. Then rat pheochromocytoma line 12 (PC12) cells oxidative model was built to evaluate the suppression of oxidative stress of three components on PC12 cells induced by H2O2. Morphological alterations, cell viability, apoptosis rate, and intracellular antioxidase system tests all indicated that WPHs exert significant protection on PC cells against H2O2-induced damage. Among them, M60 had the highest protective effect by increasing 19·3% cell survival and reducing 28·6% cell apoptosis. These results suggested hydrophobicity of WPHs was contributing to the antioxidant ability and the protective effect against oxidative damage.
    Journal of Dairy Research 10/2014;
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    ABSTRACT: The aim of this study was to investigate the effects of numerous milk compositional factors on milk coagulation properties using Partial Least Squares (PLS). Milk from herds of Jersey and Holstein-Friesian cattle was collected across the year and blended (n=55), to maximise variation in composition and coagulation. The milk was analysed for casein, protein, fat, titratable acidity, lactose, Ca2+, urea content, micelles size, fat globule size, somatic cell count and pH. Milk coagulation properties were defined as coagulation time, curd firmness and curd firmness rate measured by a controlled strain rheometer. The models derived from PLS had higher predictive power than previous models demonstrating the value of measuring more milk components. In addition to the well-established relationships with casein and protein levels, CMS and fat globule size were found to have as strong impact on all of the three models. The study also found a positive impact of fat on milk coagulation properties and a strong relationship between lactose and curd firmness, and urea and curd firmness rate, all of which warrant further investigation due to current lack of knowledge of the underlying mechanism. These findings demonstrate the importance of using a wider range of milk compositional variables for the prediction of the milk coagulation properties, and hence as indicators of milk suitability for cheese making.
    Journal of Dairy Research 10/2014;
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    ABSTRACT: European consumers are more and more aware of the credence attributes of foods, particularly of those of animal origin. The aim of the paper was to assess whether the information about production system may modify the consumer liking of cheese. Montasio PDO cheese (MC), usually made by milk from indoor reared cows of different breeds, was processed from pure milk of Italian Simmental (IS) cows (ISMC) or of IS cows grazing on mountain pasture (ALP-ISMC). A consumer test was carried out in two sessions on 60-d ripened cheeses. In the first, both cheeses were tasted by Montasio consumers in blind condition (Perceived liking, PL). Then the respondents were asked to read information about the breed and the rearing system and to give their Expected liking (EL). Two weeks after, in the second session, the same consumers tasted the two cheeses with the linked information (Actual liking, AL). Despite the similar PL average score (ISMC: 21±2·3 vs.
    Journal of Dairy Research 10/2014;
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    ABSTRACT: In order to protect peroral β-galactosidase from being degraded and hydrolyse milk lactose efficiently in the environments of gastrointestinal tract, a double-capsule delivery system composed of enteric-coated capsule and polylactic acid (PLA) nanocapsules (NCs) was developed for encapsulation of β-galactosidase. β-galactosidase-loaded PLA NCs in the size range of 100-200 nm were prepared by a modified w1/o/w2 technique. During the encapsulation process, dichloromethane/ethyl acetate (1 : 1, v/v) as the solvent composition, high-pressure homogenisation (150 bar, 3 min) as the second emulsification method and polyvinyl alcohol or Poloxamer 188 as a stabiliser in the inner phase could efficiently improve the activity retention of β-galactosidase (>90%). Subsequently, the prepared NCs were freeze-dried and filled in a hydroxypropyl methylcellulose phthalate (HP55)-coated capsule. In vitro results revealed that the HP55-coated capsule remained intact in the simulated gastric fluid and efficiently protected the nested β-galactosidase from acidic denaturation. Under the simulated intestinal condition, the enteric coating dissolved rapidly and released the β-galactosidase-loaded PLA NCs, which exhibited greater stability against enzymatic degradation and higher hydrolysis ratio (∼100%) towards milk lactose than the free β-galactosidase. These results suggest that this double-capsule delivery system represents promising candidate for efficient lactose hydrolysis in the gastrointestinal tract.
    Journal of Dairy Research 09/2014;