Effect of Aqueous Extract of the Seaweed Gracilaria domingensis on the Physicochemical, Microbiological, and Textural Features of Fermented Milks.

The effects of the Gracilaria domingensis seaweed aqueous extract in comparison with gelatin on the physicochemical, microbial, and textural characteristics of fermented milks processed with the mixed culture SAB 440 A, composed of Streptococcus thermophilus, Lactobacillus acidophilus, and Bifidobacterium animalis ssp. lactis, were investigated. The addition of G. domingensis aqueous extract did not affect pH, titratable acidity, and microbial viability of fermented milks when compared with the control (with no texture modifier) and the products with added gelatin. Fermented milk with added the seaweed aqueous extract showed firmness, consistency, cohesiveness, and viscosity index at least 10% higher than those observed for the control product (P < 0.05). At 4 h of fermentation, the fermented milks with only G. domingensis extract showed a texture comparable to that observed for products containing only gelatin. At 5 h of fermentation, firmness and consistency increased significantly (P < 0.05) in products with only seaweed extract added, a behavior not observed in products with the full amount of gelatin, probably due to the differences between the interactions of these ingredients with casein during the development of the gel network throughout the acidification of milk. The G. domingensis aqueous extract appears as a promising gelatin alternative to be used as texture modifier in fermented milks and related dairy products.

Effect of Safflower Oil on Concentration of Conjugated Linoleic Acid of Kefir Prepared by Low-fat Milk.

BACKGROUND: Conjugated linoleic acid (CLA) is a special fatty acid in dairy products with unique antioxidant and anti-cancerous effects. Kefir, a milk product, comprises normalized homogenized cow's milk, the fructose and lactulose syrup as well as a symbiotic starter which has improved probiotic characteristics. The study was aimed to discuss patents and to examine the effect of different safflower oil concentrations on CLA content of the kefir drink prepared by low-fat milk. MATERIAL AND METHODS: Safflower oil was added at 0.1, 0.3 and 0.5% (V/V) to low-fat cow's milk and six formulations of kefir samples were prepared. The CLA content of the kefir products was measured at pH=6.0 and pH=6.8 by gas chromatography. Acid and bile tolerance of bacterial microenvironment in the products were also determined. RESULTS: Substitution of natural fat content of milk with safflower oil resulted in proportional increase in the CLA contents of kefir in a dose dependent manner. The highest concentration of CLA was found under 0.5% (V/V) of safflower oil at pH 6.0 and temperature of 37 °C. Adding the Safflower oil into milk used for kefir production, increased CLA content from 0.123 (g/100 g) in pure safflower free samples to 0.322 (g/100 g) in samples with 0.5% (V/V) of safflower oil. CONCLUSION: The current study revealed that substitution of safflower oil with natural fat of cow's milk may help the production of kefir samples with remarkable increase in CLA content of final product.

Formation of volatile compounds in kefir made of goat and sheep milk with high polyunsaturated fatty acid content.

This article explored the formation of volatile compounds during the production of kefir from goat and sheep milks with high polyunsaturated fatty acids (PUFA) as a result of feeding animals forage supplemented with maize dried distillers grains with solubles (DDGS). The increased PUFA content of the goat and sheep milks resulted in significant changes to the fermentation process. In particular, apart from an increase in the time taken to ferment sheep milk, fermentation yielded less 2,3-butanedione. The highest quantities of this compound were assayed in kefir produced from goat milk with an increased content of PUFA. An increase of PUFA significantly elevated ethanal synthesis during lactose-alcohol fermentation of sheep milk. Neither the origin of milk (sheep or goat) nor the level of PUFA had any statistical effect on the amount of ethanal assayed during the fermentation of milk and within the finished product. The proportion of l(+)-lactic acid was higher in kefirs produced using goat milk compared with sheep milk and did not depend on the content of PUFA in milk fat. The content of PUFA had a significant effect on the aroma profile of the resulting kefirs. An increase in PUFA content resulted in the loss of whey aroma in goat milk kefirs and the animal odor in sheep milk kefirs, and a creamy aroma became more prevalent in kefirs made from sheep milk.

Screening of Lactobacillus strains for their ability to produce conjugated linoleic acid in milk and to adhere to the intestinal tract.

Conjugated linoleic acid (CLA) has been shown to provide beneficial effects on health; however, the amount consumed in food is far from that required for the desired effects. Thus, increasing the CLA content in dairy foods through milk fermentation with specific lactic acid bacteria (LAB) offers an interesting alternative. Moreover, some LAB may be able to adhere to the intestinal mucosa and produce CLA through endogenous synthesis. Therefore, the objective of this study was to screen LAB isolates for their ability to produce CLA in skim milk and in simulated gastrointestinal conditions. Additionally, the ability of selected CLA-producing LAB to adhere to the intestinal mucosa in a murine model was assessed. Results showed that of 13 strains of Lactobacillus tested, only 4 were able to produce CLA in skim milk supplemented with linoleic acid (13.44 ± 0.78 to 50.9 ± 0.26 µg/mL). Furthermore, these 4 Lactobacillus strains were able to survive and produce CLA in simulated gastrointestinal conditions and to adhere to the intestinal mucosa of Wistar rats after 7 d of oral inoculation with fluorescently labeled bacteria. Accordingly, these 4 Lactobacillus strains may be used to manufacture fermented dairy foods to increase CLA content, and consumption of these fermented milks may result in CLA produced endogenously by these LAB.

Study of the effect of different fermenting microorganisms on the Se, Cu, Cr, and Mn contents in fermented goat and cow milks.

The aim of this study was to determine the Se, Cu, Cr, and Mn concentrations of different types of goat- and cow-milk fermented products and evaluate the influence of fermenting bacteria (classical fermenting starters and a probiotic strain) on these concentrations. Atomic absorption spectrometry with hydride generation was used to measure Se and electrothermal atomization to measure Cu, Cr and Mn. Analytical parameters determined in the fermented milks demonstrated that the procedures used were adequate for Se, Cu, Cr, and Mn analyses. Se levels were significantly lower in fermented goat milk products than in fermented cow milk products (p<0.05). Se, Cu, Cr, and Mn levels did not differ as a function of the fermenting bacteria used in commercial fermented goat or cow milks or in the lab-produced goat yoghurt. Given the Se, and Cr intakes for healthy adults, goat and cow yogurts may be important dietary sources.

Evaluation of quality of kefir from milk obtained from goats supplemented with a diet rich in bioactive compounds.

BACKGROUND: The composition of bioactive components in dairy products depends on their content in raw milk and the processing conditions. The experimental material consisted of the milk of dairy goats supplemented with 120 g d(-1) per head of false flax cake. The aim of the study was to evaluate the quality of kefir produced from goat's milk with a higher content of bioactive components resulting from supplementation of the goats' diet with false flax cake. RESULTS: The administration of false flax cake to goats had a positive effect on the fatty acid profile of the raw milk, causing an increase in the proportion of polyunsaturated fatty acids (PUFA), including conjugated linoleic acid (CLA) and n-3 fatty acids. Their increased percentage was detected in the kefir after production as well as after storage. The processing value of the harvested milk did not differ from the qualitative characteristics of milk from goats of the control group. Increasing the proportion of bioactive components in goat's milk did not result in changes in the acidity, texture, colour, flavour, aroma or consistency of the kefir obtained. CONCLUSION: Milk and kefir obtained after the administration of false flax cake to goats contain bioactive components (PUFA including CLA, n-3 and monoenic trans fatty acids) in significant amounts. Kefir from experimental goat's milk did not differ in quality from kefir made from the milk of the control group.

Effect of Aloe vera (Aloe barbadensis Miller) on survivability, extent of proteolysis and ACE inhibition of potential probiotic cultures in fermented milk.

BACKGROUND: In the present investigation, the effect of Aloe vera gel powder on angiotensin-converting enzyme (ACE) inhibitory activity, extent of proteolysis during fermentation and survival of Lactobacillus casei NCDC19 during storage of fermented milk was studied. RESULTS: Among the different cultures screened for ACE inhibitory activity, Lactobacillus casei NCDC 19 exhibited the highest ACE inhibition (approx. 40%) as well as extent of proteolysis (0.37, Abs340). In the presence of Aloe vera (0.5% and 1% w/v) an increase in extent of proteolysis (0.460 ± 0.047 and 0.480 ± 0.027) and percent ACE inhibitory activity (44.32 ± 2.83 and 47.52 ± 1.83) was observed in comparison to control. Aloe vera powder addition also led to an increase in viable counts (>11 log cfu mL⁻¹) of L. casei NCDC 19 in fermented milk during storage for 7 days and the counts were maintained in sufficiently higher numbers. CONCLUSION: The study suggests Aloe vera to be a good functional ingredient which can be further explored for different health attributes.

Analysis of phytostanyl fatty acid esters in enriched foods via UHPLC-APCI-MS.

A method for the analysis of phytostanyl fatty acid esters, the functional ingredients of cholesterol-lowering enriched foods, was developed. The procedure is based on (i) separation of the intact esters via reversed-phase ultrahigh-performance liquid chromatography; (ii) detection by atmospheric pressure chemical ionization-mass spectrometry; and (iii) quantitation using selected ion monitoring (SIM) mode. Employing a C8 column, phytostanyl fatty acid esters sharing the same stanol nucleus could be separated according to the esterified fatty acids while esters with different stanol moieties could be distinguished via SIM based on the formation of an intense fragment ion [M - fatty acid + H](+). The suitability of the approach was demonstrated using different types of enriched foods reflecting the diversity in potential matrices (skimmed milk drinking yogurt, margarine, and soft-cheese-style spread). The developed methodology extends the analytical basis for authenticity and quality assessments of functional foods enriched with phytostanyl fatty acid esters.

Interactions of buttermilk with curcuminoids.

The ability of buttermilk to carry and stabilise a preparation of curcuminoids was examined. The quenching of intrinsic protein fluorescence confirmed that the curcuminoids interacted with proteins in buttermilk. The Stern-Volmer quenching constant was ≥ 9.4 × 10³ M⁻¹. The apparent binding constant of curcuminoids to whole buttermilk was ≥ 2.2 × 104 M⁻¹. Centrifugation of buttermilk (5% total solids, TS)--curcuminoid mixtures demonstrated that curcuminoids were partitioned into the cream (18.0%w/w, 0.64% TS), milk serum (73.3%w/w, 2.86% TS) and the casein-rich precipitate (6.76% w/w, 1.87% TS) fractions in the ratio of 1:3.7:3.5. The interaction of curcuminoids with components in the buttermilk improved its stability, as evidenced by the faster degradation of curcuminoids in phosphate buffer (pH=6.8) than in buttermilk. The ability of buttermilk to carry and stabilise curcuminoids has the potential to enable the delivery of these components into functional foods.

[Biotechnological optimization of nutrient composition of fermented dairy drink].

The receipt based on the results of carried out studies is substantiated and technology of the new fermented dairy drink containing whole milk and whey with inulin (Jerusalem artichoke extract) and optimizing initial mineral composition of raw material has been developed. The starters ascertaining optimal organoleptic properties of the drink have been selected. It has been established that Jerusalem artichoke and its derivatives in the form of syrups and extracts stimulate fermentative processes of technological microflora, with maximum activity observed with Jerusalem artichoke extract. Physical-chemical and microbiological characteristics of the drink have been defined during storage. The possibility to optimize the nutrient composition of fermented dairy product by means of introducing of Jerusalem artichoke extract into milk-protein base has been demonstrated. It has been calculated that consumption of 100 g of fermented dairy drink enriched with Jerusalem artichoke extract makes it possible to satisfy the physiological needs (recommended daily allowance--RDA) for babies from 0 to 3 months in vitamins B1, B2 and B6 by 25-35% and in minerals P, K, and Ca by 20, 68, 34, 26%. For adults receiving 250 g of fermented beverage meets RDA for vitamins B1, B2 and B6 by 10-19% and in the macronutrients P, K, Ca-by 25-35%. Designed fermented dairy drink supplemented with natural plant ingredient possesses increased antioxidant activity and may be recommended for mass consumption without any limitations.

Effects of the kefir and banana pulp and skin flours on hypercholesterolemic rats.

PURPOSE: To investigate the effect of kefir and banana pulp and skin flours on the serum levels of total cholesterol, HDL-c, LDL-c and triacylglycerols in rats fed cholesterol-rich diet. METHODS: Thirty Male Wistar rats were used. In the first 21 days, the animals were fed purified hypercholesterolemic diets, except the standard group. In the next 21 days, the animals were given modified diets: Group GC: standard diet AIN-93G; Group HIP: hypercholesterolemic diet; Group F: hypercholesterolemic diet added of 1% of banana skin flour and 7% of banana pulp flour; Group Q: hypercholesterolemic diet plus kefir suspension by oral infusion (1.5 ml/animal); Group FQ: hypercholesterolemic diet added of 1% banana skin flour and 7% of banana pulp flour plus kefir suspension (1.5 ml/animal). RESULTS: In spite of the high fiber content, the addition of banana pulp (7%) and skin (1%) flour did not alter the plasma levels of total cholesterol, HDL-c and LDL-c. However, they reduced the TG levels in 22%. Already fermented kefir reduced significantly the levels of VLDL, LDL-c and triacylglycerols, in addition to having increased HDL-c. However, it was not possible to verify the symbiotic effect between both. CONCLUSION: The results reinforce the beneficial effects of kefir in reducing the risks of cardiovascular diseases.

Effects of the kefir and banana pulp and skin flours on hypercholesterolemic rats

PURPOSE: To investigate the effect of kefir and banana pulp and skin flours on the serum levels of total cholesterol, HDL-c, LDL-c and triacylglycerols in rats fed cholesterol-rich diet. METHODS: Thirty Male Wistar rats were used. In the first 21 days, the animals were fed purified hypercholesterolemic diets, except the standard group. In the next 21 days, the animals were given modified diets: Group GC: standard diet AIN-93G; Group HIP: hypercholesterolemic diet; Group F: hypercholesterolemic diet added of 1% of banana skin flour and 7% of banana pulp flour; Group Q: hypercholesterolemic diet plus kefir suspension by oral infusion (1.5 ml/animal); Group FQ: hypercholesterolemic diet added of 1% banana skin flour and 7% of banana pulp flour plus kefir suspension (1.5 ml/animal). RESULTS: In spite of the high fiber content, the addition of banana pulp (7%) and skin (1%) flour did not alter the plasma levels of total cholesterol, HDL-c and LDL-c. However, they reduced the TG levels in 22%. Already fermented kefir reduced significantly the levels of VLDL, LDL-c and triacylglycerols, in addition to having increased HDL-c. However, it was not possible to verify the symbiotic effect between both. CONCLUSION: The results reinforce the beneficial effects of kefir in reducing the risks of cardiovascular diseases.

Fermented milk for hypertension.

BACKGROUND: Fermented milk has been suggested to have a blood pressure lowering effect through increased content of proteins and peptides produced during the bacterial fermentation. Hypertension is one of the major risk factors for cardiovascular disease world wide and new blood pressure reducing lifestyle interventions, such as fermented milk, would be of great importance. OBJECTIVES: To investigate whether fermented milk or similar products produced by lactobacilli fermentation of milk proteins has any blood pressure lowering effect in humans when compared to no treatment or placebo. SEARCH METHODS: The Cochrane Central Register of Controlled Trials (CENTRAL), English language databases, including MEDLINE (1966-2011), EMBASE (1974-2011), Cochrane Complementary Medicine Trials Register, Allied and Complementary Medicine (AMED) (1985-2011), Food science and technology abstracts (1969-2011). SELECTION CRITERIA: Randomised controlled trials; cross over and parallel studies evaluating the effect on blood pressure of fermented milk in humans with an intervention period of 4 weeks or longer. DATA COLLECTION AND ANALYSIS: Data was extracted individually by two authors, afterwards agreement had to be obtained before imputation in the review. MAIN RESULTS: A modest overall effect of fermented milk on SBP was found (MD -2.45; 95% CI -4.30 to -0.60), no effect was evident on DBP (MD -0.67; 95% CI -1.48, 0.14). AUTHORS' CONCLUSIONS: The review does not support an effect of fermented milk on blood pressure. Despite the positive effect on SBP the authors conclude, for several reasons, that fermented milk has no effect on blood pressure. The effect found was very modest and only on SBP, the included studies were very heterogeneous and several with weak methodology. Finally, sensitivity and subgroup analyses could not reproduce the antihypertensive effect. The results do not give notion to the use of fermented milk as treatment for hypertension or as a lifestyle intervention for pre-hypertension nor would it influence population blood pressure.

Effects of milk curd on saliva secretion in healthy volunteer compared to baseline, 2% pilocarpine and equivalent pH adjusted acetic acid solutions.

BACKGROUND: Dry mouth is a common clinical problem, and different products have been proposed to improve it. In this investigation, the effects of "milk curd" on the amount of saliva secretion were studied. MATERIALS AND METHODS: A total of 32 patients (aged 20-30) were selected from healthy volunteers. Milk curd concentrations of 0.5, 1, 2 and 4%, and 2% pilocarpine were prepared as drops. The impact of the drugs on the saliva weight was assessed after 1-5 min. To determine the effects of the pH of the milk curd on the amount of saliva secretion, different concentrations of acetic acid were used. RESULTS: At the end of the first minute, the differences between the data for all groups were statistically significant, and the difference between the 2% and 4% milk curd groups was higher than the others (P < 0.0001). The differences in the amount of the saliva secreted at the end of the second minute between the baseline and 4% milk curd groups and between the 0.5% and 4% MC groups were significant (P = 0.006 and P = 0.025, respectively). In total, there was no significant difference between the effect of various pH treatments and the amount of baseline saliva secretion. CONCLUSION: Milk curd has a significant local impact, and the saliva increase depends on the dose. It seems that this effect is not only related to its acidic taste. As a result, factors other than pH are involved in the effect.

High blood pressure-lowering and vasoprotective effects of milk products in experimental hypertension.

Milk casein-derived angiotensin-converting enzyme (ACE)-inhibitory tripeptides isoleucine-proline-proline (Ile-Pro-Pro) and valine-proline-proline (Val-Pro-Pro) have been shown to have antihypertensive effects in human subjects and to attenuate the development of hypertension in experimental models. The aim of the present study was to investigate the effect of a fermented milk product containing Ile-Pro-Pro and Val-Pro-Pro and plant sterols on already established hypertension, endothelial dysfunction and aortic gene expression. Male spontaneously hypertensive rats (SHR) with baseline systolic blood pressure (SBP) of 195 mmHg were given either active milk (tripeptides and plant sterols), milk or water ad libitum for 6 weeks. SBP was measured weekly by the tail-cuff method. The endothelial function of mesenteric arteries was investigated at the end of the study. Aortas were collected for DNA microarray study (Affymetrix Rat Gene 1.0 ST Array). The main finding was that active milk decreased SBP by 16 mmHg compared with water (178 (SEM 3) v. 195 (SEM 3) mmHg; P < 0.001). Milk also had an antihypertensive effect. Active milk improved mesenteric artery endothelial dysfunction by NO-dependent and endothelium-derived hyperpolarising factor-dependent mechanisms. Treatment with active milk caused mild changes in aortic gene expression; twenty-seven genes were up-regulated and eighty-two down-regulated. Using the criteria for fold change (fc) < 0.833 or > 1.2 and P < 0.05, the most affected (down-regulated) signalling pathways were hedgehog, chemokine and leucocyte transendothelial migration pathways. ACE expression was also slightly decreased (fc 0.86; P = 0.047). In conclusion, long-term treatment with fermented milk enriched with tripeptides and plant sterols decreases SBP, improves endothelial dysfunction and affects signalling pathways related to inflammatory responses in SHR.

Kefir improves the efficacy and tolerability of triple therapy in eradicating Helicobacter pylori.

Preliminary evidence has suggested that probiotics may improve eradication rates in patients infected with Helicobacter pylori treated by triple therapy. This study examined the effect of combining triple therapy with kefir, a fermented milk drink containing probiotics. A randomized, double-blind study was carried out on 82 consecutive patients with symptoms of dyspepsia and H. pylori infection confirmed by the urea breath test. Patients were given a two times a day, 14-day course of lansoprazole (30 mg), amoxicillin (1,000 mg), and clarithromycin (500 mg) with either 250 mL of kefir twice daily (triple therapy + kefir, n = 46) or 250 mL of milk containing placebo (triple therapy + placebo, n = 36). Side effects were determined using a standard questionnaire form at 15 days after beginning treatment. Patients returned for urea breath tests 45 days after beginning treatment. Significantly more triple therapy + kefir patients achieved eradication (36 of 46 [78.2%]) compared with triple therapy + placebo patients (18 of 36 [50.0%]) (P = .026, χ(2) test). Side effects were significantly less frequent and less severe in triple therapy + kefir patients than in triple therapy + placebo patients. We conclude that a 14-day regimen of triple therapy with kefir is more effective in achieving H. pylori eradication than is triple therapy alone.

Evaluation of some properties of fermented milk beverages that affect the demineralization of dental enamel.

The aim of this in vitro study was to evaluate the erosive capacity of fermented milk beverages, as well as some of their properties that affect the demineralization of dental enamel (pH, buffering capacity, fluoride, calcium and phosphorus contents). Three different batches of 6 commercial brands of fermented milk beverages were analyzed. pH evaluation was accomplished using a potentiometer. The buffering capacity was measured by adding 1 mol L-1 NaOH. Fluoride concentration was assessed by an ion specific electrode after hexamethyldisiloxane-facilitated diffusion, and calcium and phosphorus concentrations were assessed by a colorimetric test using a spectrophotometer. Sixty specimens of bovine enamel were randomly assigned to 6 groups (n = 10). They were exposed to 4 cycles of demineralization in the fermented milk and remineralization in artificial saliva. Enamel mineral loss was determined by surface microhardness (%SMHC) and profilometric tests. The samples' pH ranged from 3.51 to 3.87; the buffering capacity ranged from 470.8 to 804.2 microl of 1 mol L(-1) NaOH; the fluoride concentration ranged from 0.027 to 0.958 microgF/g; the calcium concentration ranged from 0.4788 to 0.8175 mgCa/g; and the phosphorus concentration ranged from 0.2662 to 0.5043 mgP/g. The %SMHC ranged from -41.0 to -29.4. The enamel wear ranged from 0.15 microm to 0.18 microm. In this in vitro study, the fermented milk beverages did not promote erosion of the dental enamel, but rather only a superficial mineral loss.

Evaluation of some properties of fermented milk beverages that affect the demineralization of dental enamel

The aim of this in vitro study was to evaluate the erosive capacity of fermented milk beverages, as well as some of their properties that affect the demineralization of dental enamel (pH, buffering capacity, fluoride, calcium and phosphorus contents). Three different batches of 6 commercial brands of fermented milk beverages were analyzed. pH evaluation was accomplished using a potentiometer. The buffering capacity was measured by adding 1 mol L-1 NaOH. Fluoride concentration was assessed by an ion specific electrode after hexamethyldisiloxane-facilitated diffusion, and calcium and phosphorus concentrations were assessed by a colorimetric test using a spectrophotometer. Sixty specimens of bovine enamel were randomly assigned to 6 groups (n = 10). They were exposed to 4 cycles of demineralization in the fermented milk and remineralization in artificial saliva. Enamel mineral loss was determined by surface microhardness ( percentSMHC) and profilometric tests. The samples' pH ranged from 3.51 to 3.87; the buffering capacity ranged from 470.8 to 804.2 µl of 1 mol L-1 NaOH; the fluoride concentration ranged from 0.027 to 0.958 µgF/g; the calcium concentration ranged from 0.4788 to 0.8175 mgCa/g; and the phosphorus concentration ranged from 0.2662 to 0.5043 mgP/g. The percentSMHC ranged from -41.0 to -29.4. The enamel wear ranged from 0.15 µm to 0.18 µm. In this in vitro study, the fermented milk beverages did not promote erosion of the dental enamel, but rather only a superficial mineral loss.

Particle stability in dilute fermented dairy drinks: formation of fluid gel and impact on rheological properties.

Fluid gels are known to be very shear-thinning materials with yield stress. In this study, the rheological properties of gellan and gellan-pectin fluid gels in fermented dairy drinks were evaluated using viscometric measurements. Both gellan- and gellan-pectin-containing solutions showed the rheological properties of fluid gels resulting in stabilization of particles; but no evidence of a fluid gel was observed for those with pectin alone and those with no hydrocolloid content. Unlike pectin, gellan gum was capable of creating significant values of yield stress and accordingly stabilized colloidal particles and extrinsic added solid particles in the fermented dairy drink. However, pectin improved the stability in combination with gellan. The origin of fluid gel formation was assumed to be both permanent interactions occurring between gellan and proteins, forming hairy particle gels and transient interactions between the particle gels. The significance of yield stress values for particle stability was demonstrated and two methods, including a noteworthy infinite apparent viscosity method and a conventional Bingham approach, were employed to calculate the values of yield stress. Both the methods showed a good application potential due to their simplicity, reasonable results and also wide availability of the instrument applied.

Lutein bioavailability from lutein ester-fortified fermented milk: in vivo and in vitro study.

We assessed the bioavailability of lutein from lutein-fortified fermented milk using in vivo and in vitro approaches. Twenty-four volunteers were randomized to take lutein-fortified fermented milk at two levels of fortification. Single-dose bioavailability study (2x100 ml, ca. 8 or 16 mg of lutein) was performed using a three-point approach (baseline, 3.5 and 6.5 h). Multiple-dose study consisted of consuming one serving/day (ca. 4 or 8 mg/100 ml) for 14 days. Blood samples for biochemical, hematological and lutein analysis were drawn at baseline, Day 7 and Day 14. In vitro bioaccessibility was assessed by a static gastrointestinal digestion model. Lutein content, in vitro ester hydrolysis and micellarization, and lutein concentrations achieved in serum were analyzed by HPLC. In vivo, post-prandial response was higher using the high content fermented milk, but the percentage of absorption was not different according to the dose consumed. Net increments at Day 7 and Day 14 were significantly higher on consuming the high-dose milk as well. In vitro, lutein ester hydrolysis was incomplete regardless of the amount initially present. Free lutein released was higher using the high-dose fermented milk, but the percentage of hydrolysis was similar at both levels of fortification. In the micellar phase, the percentage of free and total lutein was not different according to the dose. Our results support the suitability of the fermented milk as a carrier of lutein esters and an in vivo dose-dependent effect upon regular consumption and suggest the usefulness of in vitro models to provide relevant information to predict in vivo responses.