Bioavailability of vitamin D from fortified process cheese and effects on vitamin D status in the elderly

We conducted 2 studies to determine the effect of vitamin D-fortified cheese on vitamin D status and the bioavailability of vitamin D in cheese. The first study was designed to determine the effect of 2 mo of daily consumption of vitamin D₃-fortified (600 IU/d) process cheese on serum 25-hydroxyvitamin D (25-OHD), parathyroid hormone (PTH), and osteocalcin (OC) concentrations among 100 older (≥60 yr) men and women. Participants were randomized to receive vitamin D-fortified cheese, nonfortified cheese, or no cheese. Serum levels of 25-OHD, PTH, and OC were measured at the beginning and end of the study. There were no differences in 25-OHD, PTH, or OC after 2 mo of fortified cheese intake. The vitamin D-fortified cheese group had a greater decrease in 25-OHD than other groups, due to higher baseline 25-OHD. A second study was conducted to determine whether the bioavailability of vitamin D₂ in cheese (delivering 5880 IU of vitamin D₂/56.7-g serving) and water (delivering 32,750 IU/250 mL) is similar and whether absorption differs between younger and older adults. The second study was a crossover trial involving 2 groups of 4 participants each (younger and older group) that received single acute feedings of either vitamin D₂-fortified cheese or water. Serial blood measurements were taken over 24 h following the acute feeding. Peak serum vitamin D and area under the curve were similar between younger (23 to 50 yr) and older (72 to 84 yr) adults, and vitamin D₂ was absorbed more efficiently from cheese than from water. These studies demonstrated that vitamin D in fortified process cheese is bioavailable, and that young and older adults have similar absorption. Among older individuals, consuming 600 IU of vitamin D₃ daily from cheese for 2 mo was insufficient to increase serum 25-OHD during limited sunlight exposure.     

农家干酪在中国的发展优势

干酪的营养价值极高,是乳品行业将来发展的方向。从农家干酪的营养和加工特点出发,介绍了农家干酪所具有的发展优势,阐述了农家干酪的研究状况,并对农家干酪在中国的开发提出了一些建议。     

Characterization of cottage cheese using Weissella cibaria D30: Physicochemical,antioxidant, and antilisterial properties

This study aimed to evaluate the potential of Weissella cibaria D30 as an adjunct culture in cottage cheese, including an assessment of antioxidant, antilisterial, and compositional parameters. Cottage cheese samples were manufactured using a commercial starter culture and probiotic strains Lactobacillus rhamnosus GG (GG) or W. cibaria D30 (W) and without probiotic (control). Samples were stored at 4 ± 1°C for 28 d. Bacterial cell counts (log cfu/g) of control, GG, and W samples were counted at 0, 7, 14, 21, and 28 d. Counts of W. cibaria D30 in the W samples remained at 6.85 log cfu/g after 28 d. Total solids, fat, protein, ash, and pH were measured and no significant differences were observed in compositional parameters or pH after 28 d of storage in all cheeses except those inoculated to Listeria monocytogenes. To measure the antilisterial effect, Listeria monocytogenes was inoculated into the cottage cheese samples and bacterial cell counts were obtained at 0, 6, 12, 24, 48, 72, 96, 120, and 144 h. Listeria monocytogenes counts were less than the analytical limit of detection (<10 cfu/g) in the inoculated GG and W samples, whereas the counts of L. monocytogenes in the inoculated control sample remained at 3.0 log cfu/g after 144 h. We used the DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS [2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)] radical scavenging activity assays to assess antioxidant activity: GG and W samples exhibited significant increases in antioxidant activity compared with the control sample. These results indicate that W. cibaria D30 has potential as an adjunct culture in the dairy industry.     

Cottage cheese whey as an ingredient of cottage cheese dressing mixes

The objective of this study was to formulate and develop a good quality cottage cheese dressing using acid whey as the main ingredient. Up to 72% of cottage cheese whey was used in the dressing mixes. The percentage of fat (4.10–5.05%) and total solids (19.41–20.24%) approached the desired level and was within the legal limits for regular cottage cheese. Sensory evaluation scores for flavour, body/texture and appearance were not adversely affected by the use of acid whey. The sensory evaluation scores for all four products made with whey- or skimmed milk-based dressings were higher than the commercial control.     

Evaluation of the efficacy of commercial protective cultures to inhibit mold and yeast in cottage cheese

Biopreservation is defined as using microbes, their constituents, or both to control spoilage while satisfying consumer demand for clean-label products. The study objective was to investigate the efficacy of bacterial cultures in biopreserving cottage cheese against postprocessing fungal contamination. Cottage cheese curd and dressing were sourced from a manufacturer in New York State. Dressing was inoculated with 3 different commercial protective cultures—PC1 (mix of Lacticaseibacillus spp. and Lactiplantibacillus spp.), PC2 (Lacticaseibacillus rhamnosus), and PC3 (Lactic. rhamnosus)—following the manufacturer recommended dosage and then mixed with curd. A control with no protective culture was included. Nine species of yeast (Candida zeylanoides, Clavispora lusitaniae, Debaryomyces hansenii, Debaryomyces prosopidis, Kluyveromyces marxianus, Meyerozyma guilliermondii, Pichia fermentans, Rhodotorula mucilaginosa, and Torulaspora delbrueckii) and 11 species of mold (Aspergillus cibarius, Aureobasidium pullulans, Penicillium chrysogenum, Penicillium citrinum, Penicillium commune, Penicillium decumbens, Penicillium roqueforti, Mucor genevensis, Mucor racemosus, Phoma dimorpha, and Trichoderma amazonicum) were included in the study. Fungi strains were previously isolated from dairy processing environments and were inoculated onto the cheese surface at a rate of 20 cfu/g. Cheese was stored at 6 ± 2°C. Yeast levels were enumerated at 0, 7, 14, and 21 d postinoculation. Mold growth was visually observed on a weekly basis through d 42 of storage and imaged. Overall, the protective cultures were limited in their ability to delay the outgrowth in cottage cheese, with only 8 of the 20 fungal strains showing an effect of the cultures compared with the control. The protective cultures were not very effective against yeast, with only PC1 able to delay the outgrowth of 3 strains: D. hansenii, Tor. delbrueckii, and Mey. guilliermondii. The efficacy of these protective cultures against molds in cottage cheese was more promising, with all protective cultures showing the ability to delay spoilage of at least 1 mold strain. Both PC1 and PC2 were able to delay Pen. chrysogenum and Pho. dimorpha outgrowth, and PC1 also delayed Pen. commune, Pen. decumbens, and Pen. roqueforti to different extents compared with the controls. This study demonstrates that commercial lactic acid bacteria cultures vary in their performance to delay mold and yeast outgrowth, and thus each protective culture should be evaluated against the specific strains of fungi of concern within each specific dairy facility.     

脱脂乳热处理对农家干酪品质及其加工的影响

乳制品生产离不开热处理，用于加工的脱脂乳的品质和微生物数量对农家干酪的品质和生产中关键环节的控制都有重要的影响。针对脱脂原料乳经不同热处理后对乳中蛋白质，农家干酪的产率厦加工品质的影响进行了探讨。     

Short communication: characterization of microflora in Mexican Chihuahua cheese

This work was performed to identify the bacterial species present in 10 Chihuahua cheeses obtained from commercial producers in Mexico using 16S rRNA gene analysis. As expected, some of the agar media initially used for isolation were not very selective, supporting the growth of several unrelated bacterial species. Sequence analysis identified potential pathogens, including Escherichia coli and Staphylococcus aureus, in all raw milk samples and 2 pasteurized milk samples. Streptococcus thermophilus and Lactococcus lactis ssp. lactis were identified in 9 and 6 samples, respectively, and would serve as acidifying agents during cheese production. Lactobacilli were identified in all cheeses, with the most prevalent being Lactobacillus plantarum identified in 7 raw milk and 1 pasteurized milk cheeses. Leuconostoc mesenteroides and Streptococcus macedonicus were identified in 4 raw milk cheeses and both were present in all pasteurized milk samples, suggesting that they may play a role in the development of traditional Chihuahua cheese attributes.     

Short communication: serum and tissue concentrations of vitamin D metabolites in beef heifers after buccal dosing of 25-hydroxyvitamin D3

Sixteen crossbred (British x Continental; average un-shrunk body weight = 507.9 kg; SD = 45.6 kg) beef heifers fed a steam-flaked corn-based finishing diet with melengestrol acetate (0.4 mg/heifer daily) included to suppress estrus were used in a completely random design to evaluate the efficacy of buccal administration of 0, 10, 100, or 1000 mg of 25-hydroxyvitamin D3, (25-OH D3). Serum Ca, P, Mg, 25-OH D3, 1,25-dihydroxyvitamin D [1,25-(OH)2 D3], albumin, and protein were measured 24 h before dosing (-24 h), at dosing (0 h), and 6 and 24 h after dosing, after which the cattle were slaughtered at a commercial facility. Samples of kidneys, liver, longissimus lumborum, and triceps brachii were collected and evaluated for concentrations of 1,25-(OH)2 D3. With -24 and 0 h as baseline covariates, a significant time x treatment interaction was observed for serum 25-OH D3 and Ca concentrations, but not for serum 1,25-(OH)2 D3. Supplemental 25-OH D3 doses of 100 and 1000 mg significantly increased serum 25-OH D3 at 24 h after dosing, 1,25-(OH)2 D3 at 6 and 24 h after dosing, and serum Ca at 24 h after dosing. Similarly, buccal dosing of 1000 mg of supplemental 25-OH D3 significantly increased (approximately 2- to 3-fold) concentrations of 1,25-(OH)2 D3 in the kidney, liver, and longissimus lumborum relative to the other 3 treatments but not in triceps brachii. Serum albumin, protein, P, and Mg were not affected by treatment. Based on these results, buccal administration of 100 and 1000 mg 25-OH D3 increased vitamin D3 metabolites in serum and tissues, and it should be an effective method of delivering the vitamin.     

Short communication: comparison of covered and uncovered Schreiber test for cheese meltability evaluation

Schreiber meltability tests were performed on glass Petri dishes, with and without the Petri dish cover placed over the cheese samples, at 100, 150, and 232 degrees C. Meltability of different process cheese and Cheddar cheese samples was determined based on the melt spread distance and area. At the test temperature of 232 degrees C, the covered Schreiber was significantly superior to the uncovered test because of no crust formation, no browning, and a circular melting pattern, which were attributed to the barrier effect of covering the cheese samples (which inhibits moisture loss during the test). The covered Schreiber test data were statistically more robust as measured by the lower average coefficient of variation than the data from the traditional uncovered Schreiber test.     

Short communication: Technological and seasonal variations of vitamin D and other nutritional components in donkey milk

Vitamin D is an essential nutrient that plays a crucial role in calcium homeostasis and bone metabolism and also acts as a hormone. Although several studies on the content of vitamin D in bovine milk have been conducted, little information is available regarding donkey milk. In the context of the nutritional assessment of donkey milk, the aim of this study was to assess the vitamin D content in donkey milk and its chemical profile, with particular reference to seasonal and technological modifications after pasteurization. The study was conducted on a dairy farm that produces donkey milk for human consumption located in central Italy. At sampling time, an aliquot of total bulk milk production was sampled before and after pasteurization (63°C for 30 min without homogenization) with a total of 20 raw and 20 pasteurized milk samples. The samples were collected for 10 mo, every 15 d, from May to February 2017. All the samples were analyzed for the chemical composition and vitamin D₂ and D₃ content by HPLC after saponification. The donkey milk analyzed showed a higher average vitamin D content (raw milk: vitamin D₂ = 1.68, vitamin D₃ = 0.60 μg/100 mL; pasteurized milk: vitamin D₂ = 1.38, vitamin D₃ = 0.30 μg/100 mL) than reported for bovine and human milk. The results of the effect of pasteurization on milk did not highlight significant differences in the total content of vitamin D. However, vitamin D₃ has a poor thermal stability, which led to a significant reduction in content in pasteurized milk compared with raw milk. The total vitamin D content of donkey milk did not show significant variations between seasons; however, a higher concentration of vitamin D₃ was found in spring and summer. In conclusion, raw and pasteurized donkey milk showed a high content of vitamin D, which could be useful in meeting the deficiencies of this vitamin in humans. Further investigations are needed to improve the vitamin D content in donkey milk by increasing its endogenous synthesis or its transfer in milk and to clarify other variability factors.     

Estimation and fortification of vitamin D3 in pasteurized process cheese

The objective of this study was to develop methods for the estimation and fortification of vitamin D3 in pasteurized Process cheese. Vitamin D3 was estimated using alkaline saponification at 70 degrees C for 30 min, followed by extraction with petroleum ether:diethyl ether (90:10 vol/vol) and HPLC. The retention time for vitamin D3 was approximately 9 min. A standard curve with a correlation coefficient of 0.972 was prepared for quantification of vitamin D3 in unknown samples. In the second phase of the study, pasteurized Process cheeses fortified with commercial water- or fat-dispersible forms of vitamin D3 at a level of 100 IU per serving (28 g) were manufactured. There was no loss of vitamin D3 during Process cheese manufacture, and the vitamin was uniformly distributed. No losses of the vitamin occurred during storage of the fortified cheeses over a 9-mo period at 21 to 29 degrees C and 4 to 6 degrees C. There was an approximately 25 to 30% loss of the vitamin when cheeses were heated for 5 min in an oven maintained at 232 degrees C. Added vitamin D3 did not impart any off flavors to the Process cheeses as determined by sensory analysis. There were no differences between the water- and fat-dispersible forms of the vitamin in the parameters measured in fortified cheeses.     

Microbiological quality of ayib, a traditional Ethiopian cottage cheese

One-hundred samples of ayib, a traditional Ethiopian cottage cheese, were purchased from Awassa market and analysed for their aerobic mesophilic counts, psychrotropic counts, yeasts and molds, coliforms, spore-formers, enterococci, lactic acid bacteria, Listeria monocytogenes, staphylococci and Bacillus cereus. The majority of the samples showed counts of mesophilic aerobic bacteria, yeasts and enterococci of 10⁸, 10⁷ and 10⁷ cfu/g. About 55% of the samples were positive for coliforms and faecal coliforms. Listeria spp. were not detected in any of the samples. B. cereus and S. aureus were isolated at varying frequencies but at low numbers (10²–10³). The pH value of the samples varied between 3.3 and 4.6 with about 40% having pH lower than 3.7.     

改善维生素D3在钙镁D片中的稳定性研究

目的从配方工艺的角度找出钙镁D片中维生素D_3不稳定的原因并解决问题。方法通过样品中维生素D_3的检测情况,开展原、辅材料之间的配伍实验和改善方案实验,通过小试制粒、混合、压片、薄膜包衣和加速考察找出配方的不足之处。结果通过配方的配伍实验排查法,证明所用的原、辅料之间不存在相互反应,不会影响样品中维生素D_3稳定性;且维生素D_3粉全部外加的添加方式制成的产品中维生素D_3的稳定性优于其他添加方式制成的产品。结论将维生素D_3的添加方式改为总混合时添加,即外加,能够提高维生素D_3在钙镁D片中的稳定性。     

Short communication: Composition of coproduct streams from dairy processing: Acid whey and milk permeate

This article provides composition information for 3 abundantly available but little characterized dairy coproduct streams: acid whey from Greek yogurt (GAW), acid whey from cottage cheese (CAW), and milk permeate (MP). Three replicate samples obtained on different dates from several dairy processors were analyzed. The main component in all streams was lactose, with up to 3.5, 2.1, and 11.9% in GAW, CAW, and MP, respectively. Crude protein content ranged from 1.71 to 3.71 mg/g in GAW, 1.65 to 5.05 mg/g in CAW, and 3.2 to 4.35 mg/g in MP, and pH ranged from 4.21 to 4.48, 4.35 to 4.51, and 5.4 to 6.37, respectively. Chemical oxygen demand varied from 52,400 to 62,400 mg/L for GAW, 31,900 to 40,000 mg/L for CAW, and 127000 to 142,000 mg/L for MP; biochemical oxygen demand ranged from 45,800 to 50,500 mg/L (GAW), 32,700 to 40,000 mg/L (CAW), and 110,000 to 182,000 mg/L (MP). The GAW had the lowest pH (4.21–4.48) and highest mineral content of all streams. These data will assist processors and researchers in developing value-added uses of these dairy coproducts.     

Antagonistic action of Lactobacillus delbrueckii ssp. lactis RM2-5 toward spoilage organisms in cottage cheese

Cells of Lactobacillus delbrueckii ssp. lactis RM2-5 were added to cottage cheese stored at 7 degrees C in different amounts to determine if they would inhibit the growth of Pseudomonas fluorescens, also inoculated into the cheese samples. In addition, experiments were conducted in which no spoilage organisms were added to determine the effect of the lactobacilli on the natural background flora in the cottage cheese. For most experiments, as the numbers of lactobacilli increased, the numbers of spoilage organisms were lower than in the control on any given day of storage. In cheese inoculated with P. fluorescens, the numbers of spoilage organisms in the control had increased 5 log cycles by d 7, whereas the treatment containing the highest level of L. delbrueckii ssp. lactis RM2-5 (1.0 x 10(9) cfu/g) had not, and did not, increase over the course of the 21-d study. In the experiments where no spoilage organisms were added, lactobacilli significantly retarded the growth of gram-negative bacteria in the cheese. However, in these experiments, mold growth on the samples became a limiting factor during extended storage. The results of these experiments indicate that lactobacilli could be effective at helping control gram-negative spoilage bacteria in cottage cheese, thus potentially extending its shelf life.     

The stability of vitamin A in fortified palm olein during extended storage and thermal treatment

The stability of vitamin A in Refined Bleached Deodorised Palm Olein (RBDPOL) was studied for 24 months. Vitamin A decreased with time, temperature and thermal treatment (frying/cooking). RBDPOL fortification was observed over several temperature ranges, using PET, nylon and HDPE commercial packaging materials. After 24 months, the following vitamin A contents of 39–43 IU g^?1 (39–45%) at 16–20 °C; 35–40 IU g^?1 (43–49%) at 24–29 °C; and 28–39 IU g^?1 (45–73%) at 24–45 °C were detected at the respective temperature ranges. Results showed stability of vitamin A fortified RBDPOL vegetable oil was not stable over typical shelf life (12 months). Depletion of vitamin A accelerated when the RBDPOL vegetable oil was subjected to high temperature thermal treatment.     

Bioavailability,rheology, and sensory evaluation of mayonnaise fortified with vitamin D encapsulated in protein-based carriers

Vitamin D lost its functionality during processing and storage, thus, encapsulation with proteins is desirable to preserve bioactivity. The aim of the current study was to develop encapsulated vitamin D fortified mayonnaise (VDFM) using whey protein isolates (WPI) and soy protein isolates (SPI) as encapsulating materials in three different formulations, that is, 10% WPI, 10% SPI, and 5/5% WPI/SPI. Increased shear stress decreased the apparent viscosity along with significant effects on the loss modulus of VDFM. WPI encapsulates showed better results as compared to SPI. WPI based VDFM (M₁) depicted the best results in terms of size and dispersion uniformity of oil droplets. Hue angle and total change differed significantly among treatments. The highest value for overall acceptability was acquired by M₃ (5:5%WPI:SPI-encapsulates) thus proceed for in vivo trials. Serum vitamin D level was significantly higher in the encapsulated VDFM rat group (58.14 ± 6.29 nmol/L) than the control (37.80 ± 4.98 nmol/L). Conclusively, WPI and SPI encapsulates have the potential to improve the stability and bioavailability of vitamin D.     

Short communication: utilization of sheep's milk cheese whey in the manufacture of an alkylphenol flavor concentrate

The recovery of species-related conjugated sheep-like flavored alkylphenols from Manchego-type cheese whey by ultrafiltration was investigated. Concentrations of conjugated alkylphenols were similar in the various fractions of whey permeate collected during ultrafiltration, and this was interpreted as a reflection of their high water solubility. About 49 and 62% of conjugated 3- and 4-ethylphenols and p- and m-cresols in sheep's milk cheese whey, respectively, were recovered in the permeate after ultrafiltration with a volume concentration factor of 5.4. Cheese whey retentate correspondingly contained 38 and 28% of conjugated 3- and 4-ethylphenols and p- and m-cresols from the original whey, respectively. Permeate fractions from sheep's milk cheese whey were combined, concentrated by vacuum evaporation, and lactose was partially removed by crystallization and filtration to obtain an aqueous sheep-like flavor precursor concentrate.