Emily Mouton, Olga Cueva, Marvin Moncada, Brad Trammell, Ingrid Osorio, Charles Boeneke and Kayanush Aryana
Functional dairy foods are dairy foods that provide health benefits beyond the traditional nutrients they contain. LSU AgCenter researchers are investigating the effects of numerous health beneficial components — including carotenoids, immune enhancers, antioxidants, probiotics (health-beneficial bacteria), prebiotics (food for health-beneficial bacteria), fibers, omega-3 fatty acids, and vitamins and minerals — on key quality attributes of dairy products such as yogurts, cheeses and ice creams. Findings, in brief, from these studies are as follows:
Probiotics are health-beneficial bacteria that colonize in the lower gastrointestinal tract before they can confer health benefits on the host. Inulin is a prebiotic that increases the activity of the probiotic Lactobacillis acidophilus and increases calcium absorption. It also is a good source of dietary fiber. Yogurts were made with probiotic L. acidophilus and prebiotic inulins of various chain lengths (short, medium and long). Probiotic yogurts containing short-chain inulin had a significantly lower pH than the remaining yogurts, higher flavor scores than the yogurt containing long-chain inulin, and comparable flavor scores with the control. The yogurts containing long-chain inulin had less released serum than the control and better body and texture than the remaining yogurts. Yogurts containing prebiotics of different chain lengths had comparable L. acidophilus counts with each other but higher counts than the control.
Probiotic, fat-free, no-sugar ice creams were manufactured. Vanilla ice creams with intermediate and high levels of probiotics had lower flavor, body and texture scores compared to the lowest amount of probiotic use and the control.
Arabinogalactan is a biopolymer of two monosaccharides, arabinose and galactose. Arabinogalactans contribute to immune-enhancing activities and are important adjuncts to cancer treatment because of their capability to stimulate Natural Killer Cell toxicity, stimulate the immune system and block metastasis of tumor cells to the liver. Arabinogalactans were incorporated into yogurt in varying amounts, and although they made yogurts darker, they did not significantly influence the product thickness, microbial counts, released serum and flavor of the yogurts. Hence, arabinogalactan immune enhancer yogurts can successfully be manufactured.
Colostrum is the first milk produced by mammals. It contains antibodies to protect the newborn against diseases. Because of its immune factors, colostrum helps the body fight off harmful invaders such as viruses, bacteria, yeast and fungi. A lowered immune system function precedes or accompanies the onset of most infectious and degenerative diseases such as cancer. Powerful immune factors, such as immunoglobulins, lactoferrin and cytokines, are present in colostrum and work to restore immune function. Ice creams were manufactured with varying amounts of colostrum. Colostrum increased aerobic microbial counts and thickness (apparent viscosity) of the ice cream mix, but decreased meltdown, resulting in slower melting of the ice creams. Colostrum had no influence on flavor. In an attempt to make healthier ice creams, colostrum incorporation can be recommended in ice cream manufacture.
Six heart-healthy nutrients — thiamine (vitamin B1), riboflavin (vitamin B2), niacin (vitamin B3), folic acid (vitamin B9), manganese and magnesium — were added to yogurt to test the effects on the physico-chemical, microbiological and sensory characteristics. Fiber was added at a constant rate in all the treatments. Total solids in the control were kept constant with nonfat dry milk. Incorporation of the heart healthy nutrients at 30%, 60% and 90% of their respective daily values significantly decreased released serum, pH and lightness. The incorporation of heart healthy vitamins and minerals at any of the studied rates in yogurts did not significantly affect microbial counts, flavor, appearance, body and texture of the product. Although there were subtle yet significant changes in color and viscosity as detected by instruments, these slight changes could not be detected by sensory evaluation. Yogurts can successfully be manufactured with heart healthy nutrients.
Vision loss, especially in elderly people, is commonly caused by age-related macular degeneration (AMD). Onset of AMD can be delayed by the dietary factor lutein, which is an efficient inducer of intercellular gap junction communication. Other protective effects of lutein accumulation are the ability to absorb light in the blue wavelengths that impinge directly on the fovea of the retina, and the special ability of carotenoids to quench singlet oxygen and other reactive oxygen species. Hence, the macular cells get protected during a lifetime of oxidative stress. Nonfat yogurts were prepared with lutein as an ingredient. The lutein was incorporated prior to homogenization of the yogurt mix. Because lutein is a carotenoid, it imparted redness to the plain yogurts, but in strawberry yogurt, it was not noticed. Lutein levels remained above target throughout the five-week storage study. Lutein did not affect viscosity, pH, released serum, lightness and yellowness‐blueness values, flavor, body, texture, appearance and color scores. These results suggested that lutein was suitable for inclusion in yogurts.
Different ingredients influence different characteristics of products in different manners. Just because an ingredient is good for health, use of too much of it in a product can adversely influence the overall quality of the product. Optimum usage levels of health-beneficial ingredients need to be identified for a particular product and process to make a desirable functional dairy food.
Emily Mouton, Cueva Olga, Marvin Moncada, Brad Trammel and Ingrid Osorio are former students of Kayanush Aryana, who holds the Doyle Chambers Professorship in Animal Sciences. Charles Boeneke is now an associate professor in the School of Nutrition and Food Science.
(This article appears in the fall 2019 issue of Louisiana Agriculture.)