Short communication: Influence of an aqueous myrrh suspension on yogurt culture bacteria over yogurt shelf life.

Myrrh is an essential oil and natural flavoring approved by the US Food and Drug Administration, and it has antibacterial and antifungal activity against pathogens. Our objective was to determine the effect of an aqueous myrrh suspension on Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus counts in peptone solution and yogurt, as well as pH and titratable acidity of yogurt during 5 wk of storage at 1 to 4°C. The myrrh suspension (10% wt/vol) was prepared and incorporated into a pure culture dilution in peptone and into yogurt mix at a 1% (vol/vol) level. A control with no myrrh was also prepared, and 3 replications were conducted. Streptococcus thermophilus were enumerated using Streptococcus thermophilus agar with aerobic incubation at 37°C for 24 h, and Lactobacillus delbrueckii ssp. bulgaricus were enumerated using de Man, Rogosa, and Sharpe agar adjusted to pH 5.2, with anaerobic incubation at 43°C for 72 h. During the 8-h period after inoculation, S. thermophilus and L. delbrueckii ssp. bulgaricus counts in peptone solution at 37°C and 43°C, respectively, were not significantly different in the presence or absence of the aqueous myrrh suspension. Counts of S. thermophilus in yogurt containing myrrh (mean ± SD; 4.96 ± 0.58 log cfu/mL) were not significantly different from those in the control yogurt (4.87 ± 0.39 log cfu/mL). The log counts for L. delbrueckii ssp. bulgaricus in yogurt containing myrrh (5.04 ± 1.44 log cfu/mL) and those of the control (5.52 ± 1.81 log cfu/mL) did not differ, and the counts remained within 1 log of each other throughout 5 wk of storage. The pH of the yogurts containing the aqueous myrrh suspension was not significantly different from that of the control yogurts, and their pH values were within 0.1 pH unit of each other in any given week. Titratable acidity values remained steady around 1.1 to 1.2% lactic acid for both yogurt types throughout the storage period, with no significant differences between them. Yogurt culture bacteria can survive in the presence of a myrrh suspension in yogurt with no significant change in pH or titratable acidity. Therefore, it may be beneficial to add an aqueous myrrh suspension to yogurt.

Milk and kefir maintain aspects of health during doxorubicin treatment in rats.

Doxorubicin (DOX), a powerful anthracycline antibiotic commonly used to treat a wide variety of cancers, is associated with the production of reactive oxygen species that cause oxidative damage, resulting in cardiac dysfunction. Components of dairy may have protective effects against DOX-induced cardiac damage. Kefir is a naturally fermented milk product containing antioxidants, probiotic bacteria, and yeast in addition to the protective components of dairy. We explored the effects of dietary milk and kefir on DOX-induced cardiotoxicity in rats. We used singly housed, 10-wk-old male Sprague Dawley rats assigned to 1 of 3 isocaloric diets, control (CON n = 24), milk (MLK, n = 24), or kefir (KEF, n = 24), with equivalent macronutrient profiles. After a 9-wk dietary intervention, all animals were given either a bolus injection (15 mg/kg) of DOX (CON-DOX n = 12; MLK-DOX n = 12, KEF-DOX n = 12) or saline (CON-SAL n = 12; MLK-SAL n = 12; KEF-SAL n = 12). Body weight, grip strength, echocardiographic evaluation of cardiac geometry, and cardiac function were evaluated using echocardiography at 5 d postinjection and data were analyzed using ANOVA. Survival at d 5 post-DOX injection was 92 and 100% in KEF-DOX and MLK-DOX, respectively, and 75% in CON-DOX. By the last week of the dietary intervention, and just before injection with saline or DOX, CON weighed significantly (14%) more than the MLK and KEF. The DOX treatment resulted in significant reductions in body weight; however, we found no diet × drug interactions. The DOX treatment reduced peak grip strength compared with SAL; when compared with pre-injection measures, MLK-DOX rats did not experience a significant reduction in peak grip strength compared with CON-DOX and SAL-DOX rats. Heart mass in MLK and KEF was significantly higher when compared with CON. In summary, 9 wk of milk or kefir ingestion resulted in lower body size and higher heart mass after DOX treatment. Additionally, MLK preserved peak grip strength after DOX treatment, whereas KEF or CON did not. We observed no consistent protective effects with respect to heart dimensions and function. These findings suggest that long-term milk or kefir ingestion may be helpful in optimizing health before and during doxorubicin treatment.

Short communication: Sensory analysis of a kefir product designed for active cancer survivors.

Kefir is a fermented milk product that is a good source of protein and health-promoting bacteria. It has the potential to improve recovery from exercise and the health and well-being of cancer survivors. The purpose of this study was to explore cancer survivor attitudes about and acceptance of a kefir recovery beverage made from cultured milk, whole fruit, natural sweeteners, and other natural ingredients. Kefir was made by inoculating and fermenting milk with kefir grains. The kefir was then mixed with a fruit base and given to cancer survivors (n = 52) following a bout of exercise. Participants evaluated the acceptability of the beverage samples (overall appearance, aroma, taste, mouthfeel, and overall liking) using a 9-point hedonic scale, and they evaluated the smoothness using a 3-category just-about-right scale (not enough, just about right, and too much). They also expressed their physical and psychological feelings about the beverage using a 5-point scale (1 = not at all to 5 = extremely) and indicated their purchase intent using a binomial (yes/no) response. The health benefits of kefir were then explained, and participants sampled a second beverage (the same product), answering the same questions related to overall liking, feeling, and intent to purchase. We used a paired Student's t-test to compare beverage liking and emotion scores before and after participants learned about the health benefits of kefir. Data are presented as mean ± standard deviations. The beverage scored significantly higher for overall liking after the health benefits were explained (6.5 ± 1.8 and 7.0 ± 1.7 out of 9 before and after the explanation of health benefits, respectively). Participants showed a high intent to purchase before they learned about the health benefits (75% of participants indicated an intent to purchase, and 89% after they learned about the health benefits). The beverage received high scores overall and, except for an improvement in overall liking, we observed no significant differences in physical and psychological feelings before and after participants learned that it contained kefir and had potential health benefits. We found the beverage to be acceptable for consumption by cancer survivors, and the majority of participants showed an interest in purchasing for after exercise.

Short communication: The effects of frozen storage on the survival of probiotic microorganisms found in traditionally and commercially manufactured kefir.

Kefir is a fermented milk traditionally made from a unique starter culture, which consists of numerous bacteria and yeast species bound together in an exopolysaccharide matrix produced by certain lactic acid bacteria. Many health benefits are associated with traditionally produced kefir; however, bulging and leaking packaging, caused by secondary yeast fermentation during storage, has limited large-scale manufacture. Commercial kefir products have been designed to reduce these effects by using a pure starter culture consisting of a mixture of bacteria and yeast species that give a flavor similar to traditional kefir, but some health benefits may be lost in commercial production due to reduced microbial diversity and lack of beneficial exopolysaccharides. In this study, traditional and commercial kefir was frozen to study the effects of frozen storage on the viability of probiotic bacteria over time. Traditional kefir was prepared by inoculating 1L of pasteurized whole goat milk with approximately 30g of kefir grains. Commercial kefir was prepared by inoculating 1L of full-fat, pasteurized goat milk with a commercial kefir starter. The milk was allowed to ferment at room temperature (24-28°C) until pH 4.6 was reached. Samples were frozen (-8 to -14°C) immediately following the completion of fermentation and were thawed and plated for lactobacilli, lactococci, and yeasts on d 0, 7, 14, and 30 of frozen storage. Lactobacilli, lactococci, and yeasts were significantly reduced in number during frozen storage; however, the traditionally produced kefir was shown to have significantly higher counts of bacteria and yeast at each sampling. We concluded that frozen storage and the development of frozen kefir products could eliminate most packaging concerns associated with the large-scale manufacture of traditionally produced kefir, resulting in increased production and marketability of this healthful product.

The effects of postexercise consumption of a kefir beverage on performance and recovery during intensive endurance training.

This study was designed to determine whether kefir accentuates the positive health benefits assessed by measures in fitness, body composition, or both, as a measure of cardiovascular disease risk as well as the biomarker C-reactive protein (CRP). Sixty-seven adult males and females aged 18 to 24 yr were assigned to 1 of 4 groups: (1) endurance training + control beverage, (2) endurance training +kefir beverage,(3) active control + control beverage, or (4) active control + kefir beverage. The exercise groups completed 15 wk of structured endurancetraining while the active control groups maintained their usual exercise routine. Additionally, each group was assigned to either a kefir or a calorie/macronutrient matched placebo beverage that was consumed twice per week. No significant interactions were found among groups with respect to outcome variables with the exception of serum CRP. The endurance training was effective in improving 1.5-mile (2.41 km) times and kefir supplementation may have been a factor in attenuating the increase in CRP that was observed over the course of the intervention period. This preliminary study suggests that kefir may be involved in improving the risk profile for cardiovascular disease as defined by CRP.

Effect of pH on technological parameters and physicochemical and texture characteristics of the pasta filata cheese Telita.

The objective of this study was to determine the effect of stretching pH on technological parameters and physicochemical and texture characteristics of the pasta filata cheese Telita. A no-brine cheese-making method was used to control both melting and stretching temperatures. Six vats of cheese, each with a different stretching pH (5.2, 5.3, 5.4, 5.5, 5.6, and 5.7), were made in 2h. Cheese-making was replicated using 2 different lots of milk. Differences in stretching pH significantly affected all variables evaluated; stretching temperature and pH were positively correlated. Technological parameters showed an inverse relationship between pH and acidity and a direct relationship between melting and stretching temperature. The yield was highest as the pH increased and ranged from 11.4 to 12.9 kg of cheese/100 kg of milk. Physicochemical characteristics showed the following: moisture 48.1 to 53.5% (soft and semi-hard cheese), fat 46.3 to 54.9% (dry basis, full-fat cheese), minerals 2.8 to 3.5% (dry basis), calcium content 0.5 to 1.0% (dry basis), sodium 0.38 to 0.78% (dry basis), and whiteness index 77.2 to 84.5. Texture parameters showed that as the stretching pH increased, hardness increased, adhesiveness decreased, cohesiveness decreased, springiness increased, and chewiness increased. Samples were grouped based on principal component analysis. Group 1 contained cheeses at pH 5.2 and 5.3 and were better in terms of retention of components. Group 2 contained cheeses at pH 5.6 and 5.7. These cheeses attained the highest yields, were whitest, and presented the highest values for texture parameters except for adhesiveness and cohesiveness. The third group of cheeses at pH 5.4 and 5.5 were considered the best because they showed a good balance among all variables evaluated.

Developing a strawberry yogurt fortified with marine fish oil.

Fortified dairy products appeal to a wide variety of consumers and have the potential to increase sales in the yogurt industry and help increase intake of long-chain n-3 fatty acids. The objectives of this study were to develop a strawberry yogurt containing microencapsulated salmon oil (MSO; 2% wt/vol) and evaluate its characteristics during 1 mo of storage. Unpurified salmon oil (USO) was purified (PSO) and both USO and PSO were analyzed for peroxide value (PV), anisidine value (AV), total oxidation, free fatty acids (FFA), and moisture content. A stable emulsion was prepared with 7% PSO, 22% gum arabic, 11% maltodextrin, and 60% water. The emulsion was spray-dried to produce MSO. The MSO was added to strawberry-flavored yogurt (SYMSO) before pasteurization and homogenization, and a control (SY) without MSO was produced. Both yogurts were stored for 1 mo at 4°C and we determined the quality characteristics including acidity (pH), syneresis, thiobarbituric acid (TBA), fatty acid methyl ester composition, color, and lactic acid bacteria (LAB) count. The entire experiment was replicated 3 times. Total oxidation (unitless) of USO, PSO, and MSO was calculated to be 20.7±1.26, 10.9±0.1, and 13.4±0.25, respectively. Free fatty acid contents were 1.61±0.19%, 0.59±0.02%, and 0.77±0.02% for USO, PSO, and MSO, respectively. Eicosapentaenoic acid and docosahexaenoic acid were the predominant polyunsaturated fatty acids in MSO and in SYMSO, but neither was detected in SY. Fortification of SY with MSO had no significant effect on yogurt pH or syneresis. A decrease in concentration of lactic acid bacteria was observed during the storage of all yogurts. Thiobarbituric acid values significantly increased as storage time increased and SY had a significantly lighter (higher L*) and less yellow (lower b*) color than SYMSO. Although some slight differences were observed in the color and oxidation of SYMSO compared with SY, the study demonstrated that SY could be fortified with salmon oil.

Characteristics of reduced fat milks as influenced by the incorporation of folic acid.

Folic acid plays an important role in the prevention of neural tube defects (e.g., spina bifida and anencephaly), heart defects, facial clefts, urinary abnormalities, and limb deficiencies. Milk and milk products serve as a potential source for folic acid fortification because of the presence of folate-binding proteins that seem to be involved in folate bioavailability. Although milk is not a good source of folic acid, fortification could help in the prevention of the above-mentioned defects. The objective of this study was to examine the physicochemical characteristics of reduced fat milks fortified with folic acid. Reduced fat milks were prepared using 25, 50, 75, and 100% of the recommended dietary allowance of 400 microg of folic acid. Treatments included addition of folic acid at these levels before and after pasteurization. Color, pH, fat, protein, viscosity, folic acid concentration, folate-binding protein concentration, folate-binding protein profile, standard plate count, and coliform counts were determined on d 1, 7, 14, and 21. A consumer acceptability test was conducted on d 7. Data from the consumer panel were analyzed using ANOVA (PROC GLM) with means separation to determine the differences among treatments. Data obtained from the color, pH, fat, protein, viscosity, folic acid concentration, folate-binding protein concentration, standard plate count, and coliform counts were analyzed using the GLM with a repeated measure in time. Significant differences were determined at P < 0.05 using Tukey's Studentized Range Test. There were no differences in the electrophoretic mobility of folate-binding protein in the samples. The concentration of folic acid was significantly higher in reduced fat milks fortified with folic acid after pasteurization compared with the treatments in which folic acid was added before pasteurization. The consumer panelists did not find any significant differences in flavor, appearance, or texture of folic acid fortified reduced fat milks compared with that of the control. Fortification of reduced fat milks with folic acid can be accomplished without adversely affecting the product characteristics.